- Synthesis of 2-phenylethyl acetate in the presence of Yarrowia lipolytica KKP 379 biomass
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Increasing demand for natural products in the food industry has encouraged significant efforts toward the development of biotechnological processes for the production of flavour compounds. The aim of the present study was to synthesise 2-phenylethyl acetate, an essential aroma component for the food and cosmetic industries, by acetate ester alcoholysis with 2-phenylethanol in the presence of Yarrowia lipolytica KKP 379 biomass. Optimisation of reaction conditions were conducted, inter alia, by selection of the proper acyl donor and determination of optimal permeabilisation conditions for the yeast cell wall. Optimal reaction conditions enabled synthesis of the desired ester with an efficiency comparable to commercial enzymes, but at considerably lower cost.
- Bialecka-Florjanczyk, Ewa,Krzyczkowska, Jolanta,Stolarzewicz, Izabela,Kapturowska, Agata
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- Convenient tetrahydropyranylation of alcohols and phenols by catalytic ferric sulfate hydrate (Fe2(SO4)3· xH2O)
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Ferric sulfate hydrate (Fe2(SO4)3· xH2O) is found to be an efficient heterogeneous catalyst for the tetrahydropyranylation of alcohols and phenols at ambient or near ambient temperature. In addition, selective monotetrahydropyranylation of symmetrical diols is achieved under similar conditions. The deprotection of THP ether and direct transformation of THP ether to the corresponding acetate by Fe 2(SO4)3·xH2O is also studied. The simplicity of manipulation, mild conditions, reusable catalyst, good selectivity, and environment benign characters make this method a good alternative way for the THP protection of alcohols.
- Li, Lingjun,Zhu, Lizhi,Zhang, Xinying,Zhang, Guisheng,Qu, Guirong
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- Facile catalyzed acylation of heteroatoms using BiCl3 generated in situ from the procatalyst BiOCl and acetyl chloride
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Acylation of a variety of alcohols, phenols, aliphatic and aromatic amines, a thiol and a thiophenol proceeds efficiently using BiCl3 generated in situ from the procatalyst BiOCl and acetyl chloride in a solvent or under solventless conditions, furnishing the corresponding acylated derivatives in very good to excellent yields.
- Ghosh, Rina,Maiti, Swarupananda,Chakraborty, Arijit
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- Expanding ester biosynthesis in Escherichia coli
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To expand the capabilities of whole-cell biocatalysis, we have engineered Escherichia coli to produce various esters. The alcohol O-acyltransferase (ATF) class of enzyme uses acyl-CoA units for ester formation. The release of free CoA upon esterification with an alcohol provides the free energy to facilitate ester formation. The diversity of CoA molecules found in nature in combination with various alcohol biosynthetic pathways allows for the biosynthesis of a multitude of esters. Small to medium volatile esters have extensive applications in the flavor, fragrance, cosmetic, solvent, paint and coating industries. The present work enables the production of these compounds by designing several ester pathways in E. coli. The engineered pathways generated acetate esters of ethyl, propyl, isobutyl, 2-methyl-1-butyl, 3-methyl-1-butyl and 2-phenylethyl alcohols. In particular, we achieved high-level production of isobutyl acetate from glucose (17.2 g l -1). This strategy was expanded to realize pathways for tetradecyl acetate and several isobutyrate esters.
- Rodriguez, Gabriel M,Tashiro, Yohei,Atsumi, Shota
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- Efficient liquid phase acylation of alcohols over basic ETS-10 molecular sieves
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Acylation of alcohols with acetic acid can be carried out efficiently in the liquid phase over microporous titanosilicate ETS-10-type catalysts. The reaction was studied over ETS-10 exchanged with, Li, Na, K, Rb, Cs, Ba and H ions. Activity for acylation of primary alcohols depends on the exchanged alkali ion and increases in the order LiNaKBa～H～Rb～Cs-ETS-10. These molecular sieves are also suitable for the acylation of secondary alcohols and esterification with long chain carboxylic acids.
- Waghmode, Suresh B.,Thakur, Vinay V.,Sudalai, Arumugam,Sivasanker, Subramanian
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- Alkylchlorotins grafted to cross-linked polystyrene beads by a -(CH 2)n spacer (n-4, 6, 11): Selective, clean and recyclable catalysts for transesterification reactions
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Insoluble polystyrene grafted compounds of the type (P-H) (1-t)(P-(CH2)nSnBupCl 3-p,}t, (P-H)(1-t){P-(CH2) nSnBuO)t and (P-H)(1-t)[(P-(CH 2)nSnBuCl}2O]t/2, in which (P-H) is a cross-linked polystyrene; n=4, 6, and 11; p=0 and 1; and t the degree of functionalisation, were synthesised from Amberlite XE-305, a polystyrene cross-linked with divinylbenzene. The compounds were characterised by using elemental analysis, and IR, Raman, solid-state 117Sn NMR, and 1H and 119Sn high-resolution MAS NMR spectroscopy. The influence of the spacer length and the tin functionality on the catalytic activity of these compounds, as well as their recycling ability, was assessed in the transesterifica tion reaction of ethyl acetate with various alcohols. These studies showed significant differences in the activity of the catalysts interpreted in terms of changes in the mobility of the catalytic centres. Some of the supported catalysts could be recycled at least seven times without noticeable loss of activity. The residual tin content in the reaction products was found to be as low as 3 ppm.
- Camacho-Camacho, Carlos,Biesemans, Monique,Van Poeck, Manu,Mercier, Frederic A. G.,Willem, Rudolph,Darriet-Jambert, Karine,Jousseaume, Bernard,Toupance, Thierry,Schneider, Uwe,Gerigk, Ursula
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- Structural and catalytic characterization of a fungal baeyer-villiger monooxygenase
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Baeyer-Villiger monooxygenases (BVMOs) are biocatalysts that convert ketones to esters. Due to their high regio-, stereo- and enantioselectivity and ability to catalyse these reactions under mild conditions, they have gained interest as alternatives to chemical Baeyer-Villiger catalysts. Despite their widespread occurrence within the fungal kingdom, most of the currently characterized BVMOs are from bacterial origin. Here we report the catalytic and structural characterization of BVMOAFL838 from Aspergillus flavus. BVMOAFL838 converts linear and aryl ketones with high regioselectivity. Steady-state kinetics revealed BVMOAFL838 to show significant substrate inhibition with phenylacetone, which was more pronounced at low pH, enzyme and buffer concentrations. Para substitutions on the phenyl group significantly improved substrate affinity and increased turnover frequencies. Steady-state kinetics revealed BVMOAFL838 to preferentially oxidize aliphatic ketones and aryl ketones when the phenyl group are separated by at least two carbons from the carbonyl group. The X-ray crystal structure, the first of a fungal BVMO, was determined at 1.9 A and revealed the typical overall fold seen in type I bacterial BVMOs. The active site Arg and Asp are conserved, with the Arg found in the ginh position. Similar to phenylacetone monooxygenase (PAMO), a two residue insert relative to cyclohexanone monooxygenase (CHMO) forms a bulge within the active site. Approximately half of the gvariableh loop is folded into a short ?-helix and covers part of the active site entry channel in the non-NADPH bound structure. This study adds to the current efforts to rationalize the substrate scope of BVMOs through comparative catalytic and structural investigation of different BVMOs.
- Ferroni, Felix Martin,Tolmie, Carmien,Smit, Martha Sophia,Opperman, Diederik Johannes
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- Organic Reducing Agents. Reduction of Electron Deficient Bromides by 1,2,2,6,6-Pentamethylpiperidine (PMP)/Mercaptoethanol
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1,2,2,6,6-pentamethylpiperidine (PMP) is shown to be an effective reducing agent for the radical chain conversion of primary bromoesters in these reactions to the corresponding esters.The problem of inefficient reduction of tertiary bromoesters in these reactions has been overcome by the addition of an alkyl thiol which mediates the hydrogen atom transfer between the two hindered alkyl centers.
- Amoli, Maryam,Workentin, Mark S.,Wayner, Danial D. M.
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- Silphos [PCl3-n(SiO2)n]: A heterogeneous phosphine reagent for formylation and acetylation of alcohols and amines with ethyl formate and acetate
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Alcohols and amines are formylated and acetylated in the presence of Silphos [PCl3-n(SiO2)n] in ethyl formate and ethyl acetate in high to excellent yields. This procedure provides a method to separate the product by a simple filtration.
- Iranpoor, Nasser,Firouzabadi, Habib,Jamalian, Arezu
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- Acetylation and formylation of alcohols in the presence of silica sulfuric acid
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Alcohols are converted to esters in a mild, clean, and efficient reaction with acetic and formic acids in the presence of silica sulfuric acid. All reactions were performed under mild and completely heterogeneous conditions in refluxing n-hexane.
- Shirini, Farhad,Zolfigol, Mohammad Ali,Mohammadi, Kamal
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- Characterization of a new Baeyer-Villiger monooxygenase and conversion to a solely N-or S-oxidizing enzyme by a single R292 mutation
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Background Ar-BVMO is a recently discovered Baeyer-Villiger monooxygenase from the genome of Acinetobacter radioresistens S13 closely related to medically relevant ethionamide monooxygenase EtaA (prodrug activator) and capable of inactivating the imipenem antibiotic. Methods The co-substrate preference as well as steady-state and rapid kinetics studies of the recombinant purified protein were carried out using stopped-flow spectroscopy under anaerobic and aerobic conditions. Kd values were measured by isothermal calorimetry. Enzymatic activity was determined by measuring the amount of product formed using high pressure liquid chromatography or gas chromatography. Site-directed mutagenesis experiments were performed to decipher the role of the active site arginine-292. Results Ar-BVMO was found to oxidize ethionamide as well as linear ketones. Mechanistic studies on the wild type enzyme using stopped-flow spectroscopy allowed for the detection of the characteristic oxygenating C4a-(hydro)peroxyflavin intermediate, which decayed rapidly in the presence of the substrate. Replacement of arginine 292 in Ar-BVMO by glycine or alanine resulted in greatly reduced or no Baeyer-Villiger activity, respectively, demonstrating the crucial role of this residue in catalysis of ketone substrates. However, both the R292A and R292G mutants are capable of carrying out N- and S-oxidation reactions. Conclusions Substrate profiling of Ar-BVMO confirms its close relationship to EtaA; ethionamide is one of its substrates. The active site Arginine 292 is required for its Baeyer-Villiger activity but not for heteroatom oxidation. General significance A single mutation converts Ar-BVMO to a unique S- or N-monooxygenase, a useful biocatalyst for the production of oxidized metabolites of human drug metabolizing enzymes.
- Catucci, Gianluca,Zgrablic, Ivan,Lanciani, Francesco,Valetti, Francesca,Minerdi, Daniela,Ballou, David P.,Gilardi, Gianfranco,Sadeghi, Sheila J.
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- A simple and practical method for large-scale acetylation of alcohols and diols using bismuth triflate
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A practical method for large-scale acetylation of 1° and 2° alcohols as well as diols has been developed. The acetylation proceeds smoothly in MeCN with as little as 0.1 mol% bismuth triflate in good yields.
- Carrigan,Freiberg,Smith,Zerth,Mohan
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- Preparation of acetates catalyzed by boric acid and/or tungstophosphoric acid-modified zirconia obtained employing polyethylene glycols as pore-forming agents
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Zirconia modified with boric acid and/or tungstophosphoric acid calcined at 320 °C were prepared, characterized and used as catalysts in the production of acetates from diverse alcohols and phenols. Polyethylene glycol (PEG) of different molecular weight (400, 2000, 6000 Da) were added as low cost pore-forming agents during zirconia synthesis using zirconyl chloride as precursor and ammonium hydroxide as precipitating agent. The zirconias were impregnated with aqueous solutions of boric acid and/or tungstophosphoric acid (TPA). The borated zirconias, zirconias modified with TPA and zirconias doped with both boron and TPA were amorphous mesoporous materials with very strong acid sites, and specific surface areas SBET of around 200, 100, and 150 m2/g, respectively. The FT-IR spectra of borated zirconias exhibited the bands of boron species, while the zirconias modified with TPA presented the characteristic bands of tungstophosphate anion, and the zirconias doped with both boron and TPA showed a degradation of the TPA anion, confirmed by 31P MAS-NMR. The borated zirconias and the zirconias modified with TPA gave excellent selectivity and yield in the 2-phenylethanol esterification with acetic acid. The use of these materials allows obtaining higher or similar results than those reported in the literature. Zirconias doped with both boron and TPA gave lower values, due to the transformation of the [PW12O40]3? Keggin anion in to the [P2W21O71]6? and [PW11O39]7? species. The reactivity towards acetylation with acetic acid of different alcohols and phenols using the best catalyst was ordered according to: primary alcohols > secondary alcohols > phenols. The reactivity difference of the alcohols and phenols was correlated with the electronic density on the oxygen atom and steric effects.
- Osiglio, Lilian,Sathicq, Gabriel,Pizzio, Luis,Romanelli, Gustavo,Blanco, Mirta
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- Pentafluorophenylammonium triflate as a mild and new organocatalyst for acylation of alcohols, phenols, and amines under solvent-free condition
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A simple, inexpensive, environmentally friendly and efficient route for the acylation of a number of alcohols, phenols and amines using pentafluorophenylammonium triflate (PFPAT) as a catalyst is described. PFPAT organocatalyst is air-stable, cost-effective, easy to handle, and easily removed from the reaction mixtures.
- Khaksar, Samad,Zakeri, Hasan
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- Perchloric acid adsorbed on silica gel as a new, highly efficient, and versatile catalyst for acetylation of phenols, thiols, alcohols, and amines
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Perchloric acid adsorbed on silica gel efficiently catalyses acetylation of structurally diverse phenols, alcohols, thiols, and amines under solvent free conditions.
- Chakraborti, Asit K.,Gulhane, Rajesh
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- Highly Selective Acylation of Alcohols Using Enol Esters Catalyzed by Iminophosphoranes
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The iminophosphorane bases PhCH2N=P(MeNCH2CH2)3N and PhCH2N=P(NMe2)3 catalyze the acylation of primary alcohols with enol esters in excellent yields and in high selectivity. It was found that acid labile groups such as acetal and epoxide survive under the reaction conditions. Groups such as TBS and disulfide, which undergo cleavage in the presence of Ac2O and the Lewis acid Sc(OTf)3, are also unaffected. Diene, conjugated acetylene, oxazoline, nitro, and benzodioxane groups are also compatible with our catalyst/reagent system. Because secondary alcohols do not react under our conditions, our methodology is attractive for the selective acylation of primary alcohols. Polymer-supported iminophosphorane catalysts are also shown to be useful in these reactions, thus opening the possibility of wider applications.
- Ilankumaran, Palanichamy,Verkade, John G.
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- Catalytic esterification of alcohols, carboxylic acids and transesterification reactions with cerium(IV) triflate
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Esterification reactions of alcohols with acetic, chloroacetic, trifluoroacetic, propionic, stearic, and benzoic acids were catalyzed with Ce(OTf)4 in a solvent or under solvent-free conditions with high yields. The formylation and acetylation of primary and secondary alcohols were also easily achieved in ethyl formate and ethyl acetate. A high retention of the configuration was observed in the acetylation and formylation of (-)-menthol.
- Iranpoor, Nasser,Shekarriz, Marzieh
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- A facile and efficient one-step conversion of alcohol triphenylmethyl ethers to the corresponding acetates
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Alcohol triphenylmethyl (trityl) ethers were readily and efficiently transformed into the corresponding acetates by reaction with acetyl bromide. Triphenylmethyl ethers can also be transformed into the corresponding substituted acetates in high yields by the use of various substituted acetyl chlorides combined with sodium iodide.
- Kobayashi, Kumiko,Watahiki, Tsutomu,Oriyama, Takeshi
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- Bi(III) salts as new catalysts for the selective conversion of trimethylsilyl and tetrahydropyranyl ethers to their corresponding acetates and formates
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Bi(III) salts such as BiCl3, Bi(TFA)3 and Bi(OTf)3 were found to be efficient catalysts for the transformation of trimethylsilyl (TMS) and tetrahydropyranyl (THP) ethers to their corresponding acetates and formates with acetic acid and ethyl formate. Selective acetylation and formylation of TMS and THP ethers of alcohols in the presence of phenolic TMS and THP ethers make this method a useful and practical procedure in organic synthesis.
- Mohammadpoor-Baltork,Khosropour
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- A mechanistic insight into the organocatalytic properties of imidazolium-based ionic liquids and a positive co-solvent effect on cellulose modification reactions in an ionic liquid
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Detailed insights into the organocatalytic properties of imidazolium-based ionic liquids (Im-ILs) for transesterification of cellulose with isopropenyl acetate (IPA) are presented. According to model transesterification reactions and their computational analysis, acetate anions of Im-ILs play an essential role in the promotion of the reactions. Mechanistic considerations in the optimization of the protocol of IL-catalyzed transesterification reactions have enabled a significant improvement in reaction conditions and a positive co-solvent effect for cellulose modifications in an imidazolium acetate ionic liquid.
- Kakuchi, Ryohei,Ito, Ryo,Nomura, Shuhei,Abroshan, Hadi,Ninomiya, Kazuaki,Ikai, Tomoyuki,Maeda, Katsuhiro,Kim, Hyung J.,Takahashi, Kenji
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- Efficient approach for the chemoselective acetylation of alcohols catalyzed by a novel metal oxide nanocatalyst CuO-ZnO
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A new method has been developed for the chemoselective acetylation of alcohols with acetic anhydride in the presence of phenols using a novel, recyclable CuO-ZnO nanocatalyst. The catalyst was synthesized using the co-precipitation method and characterized by N2 adsorption-desorption, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersion scanning analyses. Furthermore, this catalyst could be recycled up to six times without significant loss in its activity.
- Albadi, Jalal,Alihosseinzadeh, Amir,Mardani, Mehdi
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- N,N′-dibromo-N,N′-1,2-ethanediylbis(benzene sulfonamide) as an efficient catalyst for acetylation and formylation of alcohols under mild conditions
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An efficient method for the acylation and formylation of alcohols and phenols by using an acylating/formylating agent (acetic anhydride and formic acid) in the presence of a catalytic amount of N,N′-dibromo-N,N′-1, 2-ethanediylbis(benzene sulfonamide) under mild and solvent-free conditions at room temperature in good to excellent yields is described. The use of protic acids and metal Lewis acids is avoided.
- Khazaei, Ardeshir,Rostami, Amin,Rosta, Zahra,Alavi, Ali
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- Synthesis of sulfonic acid containing ionic-liquid-based periodic mesoporous organosilica and study of its catalytic performance in the esterification of carboxylic acids
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A new sulfonic acid containing ionic-liquid-based periodic mesoporous organosilica (PMO-IL-SO3H) material was prepared and its catalytic application was investigated in the esterification of carboxylic acids with alcohols. The PMO-IL-SO3H nanocatalyst was first characterized with diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and nitrogen sorption analysis. Then, the catalytic performance of this material was studied in the esterification of carboxylic acids with short- and long-chain aliphatic alcohols, cyclic alcohols, and benzylic alcohols under solvent-free conditions. The results showed that the catalyst has superior activity for the conversion of several alcohols to afford the corresponding ester products in excellent yields and high purity. Moreover, the catalyst could be recovered and reused several times without a significant decrease in activity and product selectivity. Copyright
- Elhamifar, Dawood,Karimi, Babak,Moradi, Abbas,Rastegar, Javad
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- Liquid phase acylation of alcohols with acetic acid over zeolites
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The liquid phase acylation of primary and secondary alcohols were carried out with acetic acid in the presence of zeolites. LaY zeolite is found to be the best catalyst.
- Narender,Srinivasu,Kulkarni,Raghavan
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- Efficient acetylation of alcohols, phenols, and amines catalyzed by melamine trisulfonic acid (MTSA)
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Melamine trisulfonic acid (MTSA) was easily prepared by the reaction of melamine with neat chlorosulfonic acid at room temperature. This reagent can be used as an efficient catalyst for the acetylation of alcohols, phenols, and amines with Ac2O under mild and completely heterogeneous reaction conditions.
- Shirini, Farhad,Zolfigol, Mohammad Ali,Aliakbar, Ali-Reza,Albadi, Jalal
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- Alcohol acetylation with acetic acid using borated zirconia as catalyst
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The use of zirconium oxide doped with boron (borated zirconia) as catalyst in the acetylation of alcohols and phenol was studied. The catalysts were obtained by employing different preparation conditions, in order to observe the effect of the concentration of the precursor in the solution used to obtain the oxide, the concentration of the boron precursor, and the calcination temperature. All the solids showed amorphous characteristics and strong acidity. Boron addition increased the temperature range of the hydrated oxide stability, which depends on the boron concentration in the sample. Besides, the characterization by infrared spectroscopy showed an effect on the boron species present in the solid depending on the added concentration. The three preparation conditions under study affected the textural properties of the catalysts, as well as their acid strength. It was observed that in the acylation of alcohols using acetic acid as acylating agent and toluene as reaction solvent, at reflux temperature, the yield of acetylated product correlated with the acid strength of the catalysts, which depended on the preparation conditions. The best yield was achieved with a catalyst obtained using a high solution concentration of the oxide precursor (0.56 mmoles Zr/cm3), an intermediate boron concentration (15 g B2O3/100 g support) and a relatively low calcination temperature (320 °C).
- Osiglio, Lilian,Romanelli, Gustavo,Blanco, Mirta
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- Lanthanide bis[bis(1,1,1,3,3,3-hexafluoro-2-propoxy)sulfonyl]amide as a novel effective acylation catalyst
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Lanthanide complexes Ln(BHFPSA)3 {BHFPSA = N[SO2OCH(CF3)2]2} catalyse the acylation of alcohols or phenols under very mild conditions to afford esters in high yields.
- Nie, Jin,Zhao, Zhongming,Xu, Jun,Liu, Dafan
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- The effect of solvents on the thermal degradation products of two Amadori derivatives
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To enrich the flavor additives of the Maillard reaction, two Amadori analogs, N-(1-deoxy-d-fructosyl-1-yl)-l-phenylalanine ester (Derivative 1) and di-O-isopropylidene-2,3:4,5-?-d-fructopyranosyl phenylalanine ester (Derivative 2), were chemically synthes
- Li, Rui,Zhang, Shiyi,Zhang, Yudan,Zhao, Mingqin
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- Microwave oven synthesis of esters promoted by imidazole
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Using imidazole as promotion agent, primary, secondary and phenolic alcohol compounds were esterified with aliphatic and aromatic carboxylic acid anhydrides. Heating a ternary mixture of alcohol, anhydride and imidazole in an unmodified microwave oven produced esters in low to high yields, depending on the steric bulk of the alcohol.
- Hirose, Takuji,Kopek, Benjamin G.,Wang, Zhao-Hui,Yusa, Ritsuko,Baldwin, Bruce W.
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- Facile esterification of alcohols with 2-Acyl-4,5-dichloropyridazin-3(2 H)-ones under Friedel-Crafts conditions
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This paper describes the esterification of aromatic and aliphatic alcohols by using 2-acyl-4,5-dichloropyridazin-3(2H)-ones as an acyl source under Friedel-Crafts conditions. Twelve alcohols were reacted with four 2-acyl-4,5-dichloropyridazin-3(2H)-ones in the presence of AlCl3 in tetrahydrofuran at room temperature to give the corresponding esters in moderate to excellent yields. Thus, 2-acylpyridazin-3(2H)-ones serve as good and atom-economic acyl sources for the esterification of aromatic alcohols under Friedel-Crafts conditions, representing a rapid, practical, and efficient method of esterification. Georg Thieme Verlag Stuttgart. New York.
- Kim, Bo Ram,Sung, Gi Hyeon,Ryu, Ki Eun,Yoon, Hyo Jae,Lee, Sang-Gyeong,Yoon, Yong-Jin
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- Polyvinylpolypyrrolidone-bound boron trifluoride: A highly efficient catalyst for acylation of alcohols, phenols and trimethylsilyl ethers by acetic anhydride
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A highly efficient method for the acylation of alcohols, phenols and trimethylsilyl ethers with acetic anhydride is described using polyvinylpolypyrrolidone-bound boron trifluoride (PVPP-BF3) under mild and heterogeneous conditions at room temperature in good to excellent yields. The polyvinylpolypyrrolidone-boron trifluoride complex shows more water tolerant, non-corrosive and stable solid catalyst elevated Lewis acid properties.
- Mokhtary, Masoud,Qandalee, Mohammad,Najafizadeh, Faranak
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- Electron-deficient [TiIV(salophen)(OTf)2]: A new and highly efficient catalyst for the acetylation of alcohols and phenols with acetic anhydride
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In the present work, a highly efficient method for acetylation of alcohols and phenols with acetic anhydride catalyzed by high-valent [Ti IV(salophen)(OTf)2] is reported. Under these conditions, primary, secondary and tertiary alcohols as well as phenols were acetylated with short reaction times and high yields. The catalyst was reused several times without loss of its catalytic activity.
- Yadegari, Maryam,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj
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- Bismuth(III) salts as convenient and efficient catalysts for the selective acetylation and benzoylation of alcohols and phenols
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Efficient acetylation and benzoylation of alcohols and phenols with acetic and benzoic anhydrides have been carried out under catalysis of bismuth(III) salts including BiCl3, Bi(TFA)3 and Bi(OTf)3. Selective acetylation and benzoylation of alcohols in the presence of phenols is an additional advantage of this procedure.
- Mohammadpoor-Baltork, Iraj,Aliyan, Hamid,Reza Khosropour, Ahmad
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- Mild and practical acylation of alcohols with esters or acetic anhydride under distannoxane catalysis
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Distannoxane catalysts effect acylation of alcohols by action of esters and acetic anhydride. In particular, use of enol esters provides an extremely useful method. Primary alcohols are acylated in preference to secondary ones as well as phenol. Both acid- and base-sensitive functional groups remain intact. Especially unique is the discrimination of thio function which is completely tolerant under the present reaction conditions. This method is highly practical since operation is quite simple. Esters and solvents can be used without purification and no inert atmosphere is necessary. The products can be isolated simply by column chromatography or distillation without aqueous workup.
- Orita, Akihiro,Sakamoto, Katsumasa,Hamada, Yuji,Mitsutome, Akihiro,Otera, Junzo
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- Acetoxyselenation of olefins with selenium dioxide-acetic anhydride reagent system
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Olefins react with selenium dioxide-acetic anhydride reagent system to form acetoxyselenated compounds in fair yields which could be deselenised with Raney nickel to obtain the corresponding acetates. In one case the selenium product is resolved enzymatically to obtain optically pure sec. phenethyl alcohol.
- Pitre,Reddy,Vankar,Madhusudanan
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- Rapid and efficient method for acetylation of alcohols and phenols with acetic anhydride catalyzed by silica sulfate
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A rapid and efficient method is described for acetylation of a series of alcohols and phenols with acetic anhydride catalyzed by silica sulfate solid acid at room temperature or at refluxing temperature in excellent yield. Copyright Taylor & Francis Group, LLC.
- Jin, Tong-Shou,Zhao, Ying,Liu, Li-Bin,Chen, Zhuo,Li, Tong-Shuang
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- Bismuth Oxide Perchlorate as a Highly Efficient Catalyst for Heteroatom Acylation under Solvent-Free Conditions
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Bismuth oxide perchlorate efficiently catalyzes the acetylation of structurally diverse phenols, alcohols, thiols, and amines under solvent free conditions. Sterically hindered and electron deficient phenols are acetylated in excellent yields with stoichiometric amounts of Ac2O at room temperature. Acylation of acid-sensitive alcohols is carried out efficiently without competitive side reactions. Optically active substrates are acetylated without any detrimental effect on the optical purity.
- Chakraborti, Asit K.,Gulhane, Rajesh,Shivani
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- Preparation of Polydopamine Sulfamic Acid-Functionalized Silica Gel as Heterogeneous and Recyclable Nanocatalyst for Acetylation of Alcohols and Amines Under Solvent-Free Conditions
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To fabricate SiO2/PDA–SO3H nanocatalyst, a suitable method is designed for the loading of sulfonic acid groups on the surface of polydopamine (PDA)-encapsulated SiO2 nanoparticles. To bridge the gap between heterogeneous and homogeneous catalysis, surface functionalization of silica gel is an elegant procedure. The morphology, structure, and physicochemical features were specified using different analytical techniques including field emission scanning electron microscopy (FESEM), Fourier transformed infrared spectroscopy (FT-IR), high resolution-transmission electron microscopy (HR-TEM), energy dispersive X-ray spectroscopy (EDS), wavelength-dispersive X-ray spectroscopy (WDX), X-ray photoelectron spectroscopy (XPS), and back titration. The SiO2/PDA–SO3H nanoparticles are efficient nanocatalysts for the acetylation of many alcohols, phenols, and amines with acetic anhydride under solvent-free conditions in good to excellent yields. Moreover, the reuse and recovery of the catalyst was shown seven times without detectible loss in activity. Graphical Abstract: [Figure not available: see fulltext.]
- Veisi, Hojat,Vafajoo, Saba,Bahrami, Kiumars,Mozafari, Bita
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- Sequence-Based Prediction of Promiscuous Acyltransferase Activity in Hydrolases
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Certain hydrolases preferentially catalyze acyl transfer over hydrolysis in an aqueous environment. However, the molecular and structural reasons for this phenomenon are still unclear. Herein, we provide evidence that acyltransferase activity in esterases highly correlates with the hydrophobicity of the substrate-binding pocket. A hydrophobicity scoring system developed in this work allows accurate prediction of promiscuous acyltransferase activity solely from the amino acid sequence of the cap domain. This concept was experimentally verified by systematic investigation of several homologous esterases, leading to the discovery of five novel promiscuous acyltransferases. We also developed a simple yet versatile colorimetric assay for rapid characterization of novel acyltransferases. This study demonstrates that promiscuous acyltransferase activity is not as rare as previously thought and provides access to a vast number of novel acyltransferases with diverse substrate specificity and potential applications.
- Badenhorst, Christoffel P. S.,Becker, Ann-Kristin,Berndt, Leona,Bornscheuer, Uwe T.,Godehard, Simon P.,Lammers, Michael,Müller, Henrik,Palm, Gottfried J.,Reisky, Lukas
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- Direct dehydrative esterification of alcohols and carboxylic acids with a macroporous polymeric acid catalyst
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A macroporous polymeric acid catalyst was prepared for the direct esterification of carboxylic acids and alcohols that proceeded at 50-80 C without removal of water to give the corresponding esters with high yield. Flow esterification for the synthesis of biodiesel fuel was also achieved by using a column-packed macroporous acid catalyst under mild conditions without removal of water.
- Minakawa, Maki,Baek, Heeyoel,Yamada, Yoichi M. A.,Han, Jin Wook,Uozumi, Yasuhiro
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- Enhancement of activity and stability of lipase by microemulsion-based organogels (MBGs) immobilization and application for synthesis of arylethyl acetate
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Lipase from Candida rugosa (CRL) was immobilized in microemulsion-based organogels (MBGs) and subsequently applied in large scale synthesis of arylethyl acetate in organic solvents as a more stable and efficient catalyst. Various reaction parameters (solvent, temperature, substrate concentration) were investigated for enhancement of ester production. Thermal and operational stabilities were improved compared with free CRL showing its potential for continuous applications. They were more stable at 50-60 °C and showed good recovery activity, which retained 70% of their initial activity after 16 recycles in organic media and remained constant at that level thereafter. Moreover, the immobilized lipase can maintain high catalytic activity in a variety of organic solvents, while free lipase was easily inactivated in polar solvent. A series of alcohols with different substitution groups were successfully applied in CRL MBGs-catalyzed transesterification, affording higher conversions than those with the free enzyme.
- Zhang, Wei-Wei,Wang, Na,Zhou, Yu-Jie,He, Ting,Yu, Xiao-Qi
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- Highly efficient and versatile acetylation of alcohols, phenols and amines catalyzed by methylenediphosphonic acid (MDP) under solvent-free conditions
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Methylenediphosphonic Acid (MDP) was found to be a simple, cheap and reusable heterogeneous catalyst for the acetylation of structurally diverse alcohols, phenols and amines with acetic anhydride under solvent-free conditions at room temperature. This method showed preferential selectivity for the acetylation of the amino group in the presence of hydroxyl group. The method is very mild and the yields were in excellent.
- Xie, Minhao,Wang, Hongyong,Wu, Jun,He, Yongjun,Liu, Yaling,Zou, Pei
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- Molybdenum-modified mesoporous SiO2as an efficient Lewis acid catalyst for the acetylation of alcohols
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A suitable, expeditious and well-organized approach for the acetylation of alcohols with acetic anhydride in the presence of 5%MoO3-SiO2 as an optimum environmentally benign heterogeneous catalyst was developed. The high surface area obtained for 5%MoO3-SiO2, 101 m2 g-1 compared to other catalysts, 22, 23, and 44 m2 g-1 for 5%WO3-ZrO2, 5%WO3-SiO2, and 5%MoO3-ZrO2, respectively, appears to be the driving force for better catalytic activity. Amongst the two dopants used, molybdenum oxide is the better dopant compared to its tungsten oxide counterpart. High yields of up to 86% were obtained with MoO3 doping while WO3 containing catalysts did not show any activity. Other reaction parameters such as reactor stirring speed, and solvent variation were studied and revealed that the optimum stirring speed is 400 rpm and cyclohexane is the best solvent. Thus, the utilization of affordable and nontoxic materials, short reaction times, reusability, and producibility of excellent yields of the desired products are the advantages of this procedure.
- Hlatshwayo, Xolani S.,Ndolomingo, Matumuene Joe,Bingwa, Ndzondelelo,Meijboom, Reinout
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- Exploring the catalytic activity of Lewis-acidic uranyl complexes in the nucleophilic acyl substitution of acid anhydrides
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The catalytic activities of several uranyl complexes, such as N,N′-disalicylidene-o-phenelyenediaminato(ethanol)dioxouranium(vi) (UO2(salophen)EtOH), bis(dibenzoylmethanato)(ethanol)dioxouranium(vi) (UO2(dbm)2EtOH), pentakis(N,N-dimethylformamide)dioxouranium(vi) ([UO2(DMF)5]2+), and tetrakis(triphenylphosphine oxide)dioxouranium(vi) ([UO2(OPPh3)4]2+), were examined in the nucleophilic acyl substitution of acid anhydrides. Among them, [UO2(OPPh3)4]2+ was the most efficient to give ethyl acetate and acetic acid from acetic anhydride (Ac2O) and ethanol, and was resistant towards decomposition during the catalytic reaction. Several nucleophiles were also subjected to the catalytic acylation reaction using acetic and pivalic anhydride. Kinetic and spectroscopic studies suggested that [UO2(OPPh3)4]2+ interacts with Ac2O to form [UO2(Ac2O)(OPPh3)3]2+. Interaction of this actual catalyst with additional Ac2O determines the rate of the overall nucleophilic acyl substitution reaction.
- Takao, Koichiro,Akashi, Shin
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- Fluoroboric acid adsorbed on silica gel as a new and efficient catalyst for acylation of phenols, thiols, alcohols, and amines
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Fluoroboric acid supported on silica gel efficiently catalyzes acylation of structurally diverse phenols, alcohols, thiols, and amines under solvent free conditions. Acid-sensitive alcohols are smoothly acylated without competitive side reactions.
- Chakraborti, Asit K.,Gulhane, Rajesh
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- Bioproduction of Natural Phenethyl Acetate, Phenylacetic Acid, Ethyl Phenylacetate, and Phenethyl Phenylacetate from Renewable Feedstock
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Natural phenethyl acetate (PEA), phenylacetic acid (PAA), ethyl phenylacetate (Et-PA), and phenethyl phenylacetate (PE-PA) are highly desirable aroma chemicals, but with limited availability and high price. Here, green, sustainable, and efficient bioproduction of these chemicals as natural products from renewable feedstocks was developed. PEA and PAA were synthesized from l-phenylalanine (l-Phe) via novel six- and five-enzyme cascades, respectively. Whole-cell-based cascade biotransformation of 100 mm l-Phe in a two-phase system (aqueous/organic: 1 : 0.5 v/v) containing ethyl oleate or biodiesel as green solvent gave 13.6 g L?1 PEA (83.1 % conv.) and 11.6 g L?1 PAA (87.1 % conv.), respectively. Coupled fermentation and biotransformation approach produced 10.4 g L?1 PEA and 9.2 g L?1 PAA from glucose or glycerol, respectively. The biosynthesized PAA was converted to natural Et-PA and PE-PA by esterification using lipases with ethanol or 2-phenylethanol derived from sugar, affording 2.7 g L?1 Et-PA (83.1 % conv.) and 4.6 g L?1 PE-PA (96.3 % conv.), respectively.
- Li, Xirui,Li, Zhi,Sekar, Balaji Sundara
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- Discovery and Design of Family VIII Carboxylesterases as Highly Efficient Acyltransferases
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Promiscuous acyltransferase activity is the ability of certain hydrolases to preferentially catalyze acyl transfer over hydrolysis, even in bulk water. However, poor enantioselectivity, low transfer efficiency, significant product hydrolysis, and limited substrate scope represent considerable drawbacks for their application. By activity-based screening of several hydrolases, we identified the family VIII carboxylesterase, EstCE1, as an unprecedentedly efficient acyltransferase. EstCE1 catalyzes the irreversible amidation and carbamoylation of amines in water, which enabled the synthesis of the drug moclobemide from methyl 4-chlorobenzoate and 4-(2-aminoethyl)morpholine (ca. 20 % conversion). We solved the crystal structure of EstCE1 and detailed structure–function analysis revealed a three-amino acid motif important for promiscuous acyltransferase activity. Introducing this motif into an esterase without acetyltransferase activity transformed a “hydrolase” into an “acyltransferase”.
- Müller, Henrik,Godehard, Simon P.,Palm, Gottfried J.,Berndt, Leona,Badenhorst, Christoffel P. S.,Becker, Ann-Kristin,Lammers, Michael,Bornscheuer, Uwe T.
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supporting information
p. 2013 - 2017
(2020/11/30)
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- ZWITTERIONIC CATALYSTS FOR (TRANS)ESTERIFICATION: APPLICATION IN FLUOROINDOLE-DERIVATIVES AND BIODIESEL SYNTHESIS
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An amide/iminium zwitterion catalyst has a catalyst pocket size that promotes transesterification and dehydrative esterification. The amide/iminium zwitterions are easily prepared by reacting aziridines with aminopyridines. The reaction can be applied a wide variety of esterification processes including the large-scale synthesis of biodiesel. The amide/iminium zwitterions allow the avoidance of strongly basic or acidic condition and avoidance of metal contamination in the products. Reactions are carried out at ambient or only modestly elevated temperatures. The amide/iminium zwitterion catalyst is easily recycled and reactions proceed in high to quantitative yields.
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Paragraph 0013; 0028
(2021/01/29)
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- Method for promoting acylation of amine or alcohol by carbon dioxide
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The invention relates to a method for promoting acylation of amine or alcohol by carbon dioxide, which comprises the following steps of: mixing an amine compound, carboxylate or thiocarboxylate compound and a reaction solvent under the action of carbon dioxide, and reacting to obtain an amide compound, or under the action of carbon dioxide, mixing the alcohol compound, the thiocarboxylate compound and the reaction solvent [gamma]-valerolactone, and reacting to obtain the ester compound. According to the invention, under the promotion action of carbon dioxide, carboxylate or thiocarboxylate is used as an acylation reagent, and amine and alcohol are converted into amide and ester compounds in the absence of a transition metal catalyst, so that acylation reagents such as acyl chloride or anhydride with irritation and corrosivity are avoided; and the method has the advantages of simple operation, mild reaction conditions, high tolerance of substrate functional groups, strong applicability and high yield, and provides an efficient, reliable and economical preparation method for synthesis of amide and ester compounds.
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Paragraph 0034-0035
(2021/05/29)
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- Evaluation of gem-Diacetates as Alternative Reagents for Enzymatic Regio-and Stereoselective Acylation of Alcohols
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Geminal diacetates have been used as sustainable acyl donors for enzymatic acylation of chiral and nonchiral alcohols. Especially, it was revealed that geminal diacetates showed higher reactivity than vinyl acetate for hydrolases that are sensitive to acetaldehyde. Under optimized conditions for enzymatic acylation, several synthetically relevant saturated and unsaturated acetates of various primary alcohols were obtained in very high yields up to 98% without E/Z isomerization of the double bond. Subsequently, the acyl donor was recreated from the resulting aldehyde and reused constantly in acylation. Therefore, the developed process is characterized by high atomic efficiency. Moreover, it was shown that acylation using geminal diacetates resulted in remarkable regioselectivity by discriminating among the primary and secondary hydroxyl groups in 1-phenyl-1,3-propanediol providing exclusively 3-acetoxy-1-phenyl-propan-1-ol in good yield. Further, enzymatic kinetic resolution (EKR) and chemoenzymatic dynamic kinetic resolution (DKR) protocols were developed using geminal diacetate as an acylating agent, resulting in chiral acetates in high yields up to 94% with enantiomeric excesses exceeding 99%.
- Koszelewski, Dominik,Brodzka, Anna,Madej, Arleta,Trzepizur, Damian,Ostaszewski, Ryszard
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p. 6331 - 6342
(2021/05/06)
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- IrIII-Catalyzed direct syntheses of amides and esters using nitriles as acid equivalents: A photochemical pathway
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An unprecedented IrIII[df(CF3)ppy]2(dtbbpy)PF6-catalyzed simple photochemical process for direct addition of amines and alcohols to the relatively less reactive nitrile triple bond is described herein. Various amides and esters are synthesized as the reaction products, with nitriles being the acid equivalents. A mini-library of different types of amides and esters is made using this mild and efficient process, which uses only 1 mol% of photocatalyst under visible light irradiation (λ = 445 nm). The reaction strategy is also efficient for gram-scale synthesis.
- Talukdar, Ranadeep
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supporting information
p. 5303 - 5308
(2020/04/17)
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- KMnO4-catalyzed chemoselective deprotection of acetate and controllable deacetylation-oxidation in one pot
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A novel and efficient protocol for chemoselective deacetylation under ambient conditions was developed using catalytic KMnO4. The stoichiometric use of KMnO4 highlighted the dual role of a heterogeneous oxidant enabling direct access to aromatic aldehydes in one-pot sequential deacetylation-oxidation. The reaction employed an alternative solvent system and allowed the clean transformation of benzyl acetate to sensitive aldehyde in a single step while preventing over-oxidation to acids. Use of inexpensive and readily accessible KMnO4 as an environmentally benign reagent and the ease of the reaction operation were particularly attractive, and enabled the controlled oxidation and facile cleavage of acetate in a preceding step. This journal is
- Gurawa, Aakanksha,Kumar, Manoj,Rao, Dodla S.,Kashyap, Sudhir
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supporting information
p. 16702 - 16707
(2020/10/27)
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- Amide/Iminium Zwitterionic Catalysts for (Trans)esterification: Application in Biodiesel Synthesis
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A class of zwitterionic organocatalysts based on an amide anion/iminium cation charge pair has been developed. The zwitterions are easily prepared by reacting aziridines with aminopyridines. They are catalytically applicable to transesterifications and dehydrative esterifications. Mechanistic studies reveal that the amide anion and iminium cation work synergistically in activating the reaction partners, with the iminium cationic moiety interacting with the carbonyl substrates through nonclassical hydrogen bonding. The reaction can be applied to large-scale synthesis of biodiesel under mild conditions.
- Lam, Ying-Pong,Ng, Wing-Hin,Tan, Fei,Tse, Ying-Lung Steve,Wang, Xinyan,Yeung, Ying-Yeung
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p. 8083 - 8092
(2019/08/26)
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- Efficient Enzymatic Preparation of Flavor Esters in Water
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A straightforward biocatalytic method for the enzymatic preparation of different flavor esters starting from primary alcohols (e.g., isoamyl, n-hexyl, geranyl, cinnamyl, 2-phenethyl, and benzyl alcohols) and naturally available ethyl esters (e.g., formate, acetate, propionate, and butyrate) was developed. The biotransformations are catalyzed by an acyltransferase from Mycobacterium smegmatis (MsAcT) and proceeded with excellent yields (80-97%) and short reaction times (30-120 min), even when high substrate concentrations (up to 0.5 M) were used. This enzymatic strategy represents an efficient alternative to the application of lipases in organic solvents and a significant improvement compared with already known methods in terms of reduced use of organic solvents, paving the way to sustainable and efficient preparation of natural flavoring agents.
- Perdomo, Igor Chiarelli,Gianolio, Stefania,Pinto, Andrea,Romano, Diego,Contente, Martina Letizia,Paradisi, Francesca,Molinari, Francesco
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p. 6517 - 6522
(2019/06/20)
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- 'Clean' hydrolase reactions using commercial washing powder
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We report the use of commercial laundry powder as a biocatalyst for a range of lipase-catalysed reactions including (trans)esterification, ester hydrolysis and chemoenzymatic epoxidation reactions. The enzymatic laundry powder exhibited excellent stability and recyclability, making it a readily available and cheap biocatalyst for chemical transformations.
- Zhang, Jie,Tonin, Fabio,Zhang, Wuyuan,Hagedoorn, Peter-Leon,Mallée, Lloyd,Hollmann, Frank
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p. 24039 - 24042
(2019/08/15)
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- Application of Yttrium Iron Garnet as a Powerful and Recyclable Nanocatalyst for One-Pot Synthesis of Pyrano[2,3-c]pyrazole Derivatives under Solvent-Free Conditions
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The application of yttrium iron garnet (YIG) superparamagnetic nanoparticles as a new recyclable and highly efficient heterogeneous magnetic catalyst for one-pot synthesis of pyrano[2,3-c]pyrazole derivatives under solvent-free conditions, as well as etherification and esterification reactions are described. The advantages of the proposed method include the lack of organic solvents, clean reaction, rapid removal of the catalyst, short reaction times, excellent yields, and recyclability of the catalyst.
- Sedighinia,Badri,Kiasat
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p. 1755 - 1763
(2020/01/11)
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- Cycloaddition of CO2 with epoxides and esterification reactions using the porous redox catalyst Co-POM@MIL-101(Cr)
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The catalytic activity of the recently reported Co-POM@MIL-101(Cr) composite, synthesized from K5[CoW12O40] (Co-POM) and chromium(iii) terephthalate (MIL-101), was studied in the solvent-free cycloaddition of CO2 with epoxides and esterification of acetic acid with various alcohols. The materials containing varying amounts of Co-POM were synthesized using a one-pot HF-free method in a "bottle around ship" strategy. The material was thoroughly characterized using several methods such as powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance spectroscopy (EPR). Temperature programmed desorption (TPD) of NH3 and CO2, and the CO2 adsorption capacity (adsorption isotherms) were used to study the acid-base properties of the materials. The combination of the electron-transfer character of Co(iii)-POM and ordered mesopores in MIL-101(Cr) creates an efficient catalytic system with mild conditions (90 °C and 20 bar CO2 pressure) for solvent-free cycloaddition of CO2 to various epoxides. Esterification of acetic acid with alcohols was also carried out using the Co-POM@MIL-101 catalysts and high yields were achieved for different alcohols. The catalysis experiments also clearly show that the active site in this heterogeneous catalyst is the Co(iii) center in the Keggin anion structure. It presumably conducts both the cycloaddition of CO2 to epoxides and the esterification reaction via an outer-sphere electron transfer mechanism using the Co(iii)/Co(ii) redox pair. The heterogeneous Co-POM@MIL-101 catalysts were separated by simple filtration and reused five times in the cycloaddition of CO2 with styrene epoxide and seven times for the esterification of acetic acid with benzyl alcohol with negligible leaching of Co-POM and no considerable loss of activity.
- Marandi, Afsaneh,Bahadori, Mehrnaz,Tangestaninejad, Shahram,Moghadam, Majid,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj,Frohnhoven, Robert,Mathur, Sanjay,Sandleben, Aaron,Klein, Axel
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p. 15585 - 15595
(2019/10/19)
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- Acylation of Phenols, Alcohols, Thiols, Amines and Aldehydes Using Sulfonic Acid Functionalized Hyper-Cross-Linked Poly(2-naphthol) as a Solid Acid Catalyst
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Abstract: The hyper-cross-linked porous poly(2-naphthol) fabricated by the Friedel–Crafts alkylation of 2-naphthol has been functionalized with sulfonic acid to obtain a solid acid catalyst. The catalyst is applied for the protection of phenol, alcohols, thiols, amines and aldehydes with acetic anhydride at room temperature. The catalytic protection using the new solid acid is featured by achieving high yield at neat condition, needing no aqueous work-up and/or chromatographic separation, and showing excellent recycling efficiency, suggesting the potential of this sulfonated porous polymers as a new protection protocol in a wide range of sustainable chemical reactions. Graphical Abstract: [Figure not available: see fulltext.].
- Kalla, Reddi Mohan Naidu,Reddy, Sirigireddy Sudharsan,Kim, Il
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p. 2696 - 2705
(2019/05/28)
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- Fe3O4@PEG core/shell nanoparticles as magnetic nanocatalyst for acetylation of amines and alcohols using ultrasound irradiations under solvent-free conditions
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Abstract: Ultrasound irradiation was used to prepare one-pot Fe3O4@PEG core/shell nanostructure for the first time. The morphology, structure, and physicochemical properties were specified by different analytical techniques including field emission scanning electron microscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray powder diffraction, and vibrating sample magnetometer. For acetylation of phenols, alcohols, and amines, the synthesized Fe3O4@PEG core/shell nanoparticles were used as an efficient heterogeneous and green catalyst with acetic anhydride under sonication applying mild reaction conditions. Different electron-withdrawing and electron-donating substrates indicate a prominent yield of desired products with the merit of reusability of Fe3O4@PEG nanocatalyst and magnetic separation. Graphical Abstract: [Figure not available: see fulltext.].
- Veisi, Hojat,Nikseresht, Ahmad,Rostami, Afsaneh,Hemmati, Saba
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p. 507 - 520
(2018/10/24)
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- Synthesis method of p-hydroxyphenethyl alcohol
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The invention discloses a method for synthesizing p-hydroxyphenethyl alcohol from phenethyl alcohol as a raw material. The method comprises the steps as follows: firstly, phenethyl alcohol and acid anhydride are subjected to an esterification reaction to obtain phenethyl alcohol ester; then, phenethyl alcohol ester and acid anhydride are subjected to an electrophilic substitution reaction under the action of a catalyst and a catalyst promoter to obtain 4-acryl phenethyl alcohol ester; next, 4-acryl phenethyl alcohol ester and hydrogen peroxide are subjected to a Baeyer-Villiger oxidation reaction under the action of organic acid and an oxidation catalyst to obtain 4-acyloxy phenethyl alcohol ester; finally, the 4-acyloxy phenethyl alcohol ester is subjected to a hydrolysis reaction in alkaline water to obtain p-hydroxyphenethyl alcohol. The process for synthesizing p-hydroxyphenethyl alcohol has the advantages that raw materials are widely sourced, the yield is high, the process is concise, few three wastes are produced and industrialization is easy to realize.
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Paragraph 0038; 0039; 0040
(2019/09/17)
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- Protection of COOH and OH groups in acid, base and salt free reactions
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We report an iron-catalyzed general functional group protection method with inexpensive reagents. This environmentally benign process does not use acids or bases, and does not produce waste products. Further purification beyond filtration and evaporation is, in most cases, unnecessary. Free COOH and OH groups can be protected in a one-pot reaction.
- Zhu, Xiaotao,Qian, Bo,Wei, Rongbiao,Huang, Jian-Dong,Bao, Hongli
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supporting information
p. 1444 - 1447
(2018/04/12)
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- Lipase-mediated selective acetylation of primary alcohols in ethyl acetate
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An environmental friendly process to selectively acetylate primary alcohols was demonstrated. The esterification process consists of treatment of a primary alcohol in the presence of immobilized C. antarctica lipase (Novozyme-435) in ethyl acetate at room temperature. Primary alcohols were acetylated in the presence of secondary alcohols and phenols.
- de Souza, Ernane C.,Romero-Ortega, Moises,Olivo, Horacio F.
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supporting information
p. 287 - 290
(2017/12/29)
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- Ester Synthesis in Water: Mycobacterium smegmatis Acyl Transferase for Kinetic Resolutions
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The acyl transferase from Mycobacterium smegmatis (MsAcT) catalyses transesterification reactions in aqueous media because of its hydrophobic active site. Aliphatic cyanohydrin and alkyne esters can be synthesised in water with excellent and strikingly opposite enantioselectivity [(R);E>37 and (S);E>100, respectively]. When using this enzyme, the undesired hydrolysis of the acyl donor is an important factor to take into account. Finally, the choice of acyl donor can significantly influence the obtained enantiomeric excesses. (Figure presented.).
- de Leeuw, Nicolas,Torrelo, Guzman,Bisterfeld, Carolin,Resch, Verena,Mestrom, Luuk,Straulino, Emanuele,van der Weel, Laura,Hanefeld, Ulf
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p. 242 - 249
(2017/11/16)
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- Synthetic method of phenethyl acetate
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The invention discloses a synthetic method of phenethyl acetate. Phenethyl alcohol, acetic anhydride, Na2SiO3.9H2O, SiO2, H2PtCl6 and NaBH4 are used as main raw materials; and the traditional method for preparing the phenethyl acetate generally adopts sulfuric acid, phosphoric acid and other strong acid catalyst, so that not only is the quality of a product low due to more side reactions, but alsothe equipment is severely corroded. The synthetic process of the invention adopts the phenethyl alcohol and acetic anhydride to have nucleophilic substitution reaction in the presence of the catalystPt/SiO2 to obtain phenethyl acetate, the esterification of the phenethyl alcohol adopts the high-performance catalyst, the dichloroethane is selected to substitute the aromatic hydrocarbon as the reaction solvent, the esterification reaction effect is good, and the yield and purity can be greatly improved.
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Paragraph 0009; 0011-0023; 0030
(2019/01/04)
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- Overriding Traditional Electronic Effects in Biocatalytic Baeyer-Villiger Reactions by Directed Evolution
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Controlling the regioselectivity of Baeyer-Villiger (BV) reactions remains an ongoing issue in organic chemistry, be it by synthetic catalysts or enzymes of the type Baeyer-Villiger monooxygenases (BVMOs). Herein, we address the challenging problem of switching normal to abnormal BVMO regioselectivity by directed evolution using three linear ketones as substrates, which are not structurally biased toward abnormal reactivity. Upon applying iterative saturation mutagenesis at sites lining the binding pocket of the thermostable BVMO from Thermocrispum municipale DSM 44069 (TmCHMO) and using 4-phenyl-2-butanone as substrate, the regioselectivity was reversed from 99:1 (wild-type enzyme in favor of the normal product undergoing 2-phenylethyl migration) to 2:98 in favor of methyl migration when applying the best mutant. This also stands in stark contrast to the respective reaction using the synthetic reagent m-CPBA, which provides solely the normal product. Reversal of regioselectivity was also achieved in the BV reaction of two other linear ketones. Kinetic parameters and melting temperatures revealed that most of the evolved mutants retained catalytic activity, as well as thermostability. In order to shed light on the origin of switched regioselectivity in reactions of 4-phenyl-2-butanone and phenylacetone, extensive QM/MM and MD simulations were performed. It was found that the mutations introduced by directed evolution induce crucial changes in the conformation of the respective Criegee intermediates and transition states in the binding pocket of the enzyme. In mutants that destabilize the normally preferred migration transition state, a reversal of regioselectivity is observed. This conformational control of regioselectivity overrides electronic control, which normally causes preferential migration of the group that is best able to stabilize positive charge. The results can be expected to aid future protein engineering of BVMOs.
- Li, Guangyue,Garcia-Borràs, Marc,Fürst, Maximilian J. L. J.,Ilie, Adriana,Fraaije, Marco W.,Houk,Reetz, Manfred T.
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supporting information
p. 10464 - 10472
(2018/08/03)
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- B2pin2-Mediated Palladium-Catalyzed Diacetoxylation of Aryl Alkenes with O2 as Oxygen Source and Sole Oxidant
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A novel palladium-catalyzed alkene diacetoxylation with dioxygen (O2) as both the sole oxidant and oxygen source is developed, which was identified by 18O-isotope labeling studies. Control experiments suggested that bis(pinacolato)diboron (B2pin2) played a dominant intermediary role in the formation of a C-O bond. This method performed good functional group tolerance with moderate to excellent yields, which could be successfully applied to the late-stage modification of natural products. Furthermore, an atmospheric pressure of dioxygen enhances the practicability of the protocol.
- Huang, Jiuzhong,Ouyang, Lu,Li, Jianxiao,Zheng, Jia,Yan, Wuxin,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 5090 - 5093
(2018/09/12)
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- Sulfonium Salts as Alkylating Agents for Palladium-Catalyzed Direct Ortho Alkylation of Anilides and Aromatic Ureas
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A novel method for the ortho alkylation of acetanilide and aromatic urea derivatives via C-H activation was developed. Alkyl dibenzothiophenium salts are considered to be new reagents for the palladium-catalyzed C-H activation reaction, which enables the transfer of methyl and other alkyl groups from the sulfonium salt to the aniline derivatives under mild catalytic conditions.
- Simkó, Dániel Cs.,Elekes, Péter,Pázmándi, Vivien,Novák, Zoltán
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supporting information
p. 676 - 679
(2018/02/09)
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- Zirconocene-catalyzed direct (trans)esterification of acyl acids (esters) and alcohols in a strict 1:1 ratio under solvent-free conditions
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A highly efficient way for the direct (trans)esterification of acyl acids (esters) and alcohols in a strict 1:1 ratio using a zirconocene complex (1, 1 mol%), a strong Lewis acid of good water tolerance, as a catalyst under solvent-free conditions has been developed. A wide range of acid and alcohol (esters) substrates undergo (trans)esterification to produce carboxylic ester motifs in moderate to good or excellent yields with good functional tolerance, such as that towards C-Br as well as CC and CC bonds. And complex 1 can be recycled six times without showing a significant decline in catalytic efficiency. It was demonstrated that cyclandelate, which is used to treat high blood pressure as well as heart and blood-vessel diseases, can be directly synthesized on a gram scale with 81% yield (6.70 g) using complex 1.
- Tang, Zhi,Jiang, Qiutao,Peng, Lifen,Xu, Xinhua,Li, Jie,Qiu, Renhua,Au, Chak-Tong
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supporting information
p. 5396 - 5402
(2017/11/22)
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- Ethyl acetate as an acetyl surrogate for the iodine catalyzed acetylation of alcohols
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The use of readily available ethyl acetate in the presence of iodine as an alternative acetylating agent is reported. Amines and phenols were unreactive under the examined reaction conditions, indicating that the method is highly chemoselective.
- Basumatary, Grace,Bez, Ghanashyam
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supporting information
p. 4312 - 4315
(2017/10/13)
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- Reusable and efficient polyvinylpolypyrrolidone-supported triflic acid catalyst for acylation of alcohols, phenols, amines, and thiols under solvent-free conditions
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Abstract: A triflic acid-functionalized polyvinylpolypyrrolidone was prepared and fully characterized by FT-IR, TGA, and SEM. This super acidic solid catalyst shows high catalytic activity for selective acylation of alcohols, phenols, amines, and thiols with anhydrides under solvent-free conditions at room temperature. In addition, this method features an easy to handle solid super acid catalyst and an operationally simple procedure, affording the desired acylated products in excellent yields. Graphical abstract: [Figure not available: see fulltext.].
- Tajbakhsh, Mahgol,Tajbakhsh, Mahmoud,Khaksar, Samad,Gazvini, Helia Janatian,Heidary, Marzieh
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p. 1117 - 1122
(2017/05/10)
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- Highly Active Manganese-Mediated Acylation of Alcohols with Acid Chlorides or Anhydrides
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To explore further the practical uses of highly active manganese (Mn?), a variety of alcohols were treated with Mn?, and the resulting complexes were coupled with acid chlorides and/or acetic anhydride in the absence of any extra catalyst. The subsequent reactions took place smoothly under mild conditions, providing the corresponding O-acylation products in good to excellent isolated yields.
- Joo, Seong-Ryu,Youn, Young-Jin,Hwang, Young-Ran,Kim, Seung-Hoi
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p. 2665 - 2669
(2017/10/07)
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- Selective C-H bond electro-oxidation of benzylic acetates and alcohols to benzaldehydes
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A chemical oxidant-free and mediator-free, direct electro-oxidation of both benzylic alcohols and benzylic esters are reported. The scope of the reaction is explored as a function of both steric and electronic effects. Expansion of the scope to non-benzylic and heteroaryl substrates is investigated. Functionalisation of esters and alcohols selectively to the aldehyde oxidation level using a traceless electron approach is reported.
- Barone, Mateus R.,Jones, Alan M.
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p. 10010 - 10015
(2017/12/26)
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- Selective acetylation of primary alcohols by ethyl acetate
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A KOtBu and ethyl acetate mediated efficient methodology has been developed for the acetylation of primary and secondary alcohols where ethyl acetate is the source of acetyl group. The reaction is fast, mild, efficient, and highly selective towards the primary alcohols.
- Singha, Raju,Ray, Jayanta K.
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supporting information
p. 5395 - 5398
(2016/11/11)
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- Efficient O-Acylation of Alcohols and Phenol Using Cp2TiCl as a Reaction Promoter
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A method has been developed for the conversion of primary, secondary, and tertiary alcohols, and phenol, into the corresponding esters at room temperature. The method uses a titanium(III) species generated from a substoichiometric amount of titanocene dichloride together with manganese(0) as a reductant, as well as methylene diiodide. It involves a transesterification from an ethyl ester, or a reaction with an acyl chloride. A radical mechanism is proposed for these transformations.
- Durán-Pe?a, María Jesús,Botubol-Ares, José Manuel,Hanson, James R.,Hernández-Galán, Rosario,Collado, Isidro G.
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supporting information
p. 3584 - 3591
(2016/07/28)
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- Development and Applications of Transesterification Reactions Catalyzed by N-Heterocyclic Olefins
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A novel method to utilize N-heterocyclic olefins (NHOs), the alkylidene derivatives of N-heterocycic carbenes, as organocatalysts to promote transesterification reactions has been developed. Because of their strong Br?nsted/Lewis basicity, NHOs can enhance the nucleophilicity of alcohols for their acylation reactions with carboxylic esters. This transformation can be employed in industrially relevant processes such as the production of biodiesel, the depolymerization of polyethylene terephthalate (PET) from plastic bottles for recycling purposes, and the ring-opening polymerization of cyclic esters to form biodegradable polymers such as polylactide (PLA) and polycaprolactone (PCL).
- Blümel, Marcus,Noy, Janina-Miriam,Enders, Dieter,Stenzel, Martina H.,Nguyen, Thanh V.
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supporting information
p. 2208 - 2211
(2016/06/01)
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- Proton-gradient-transfer acid complexes and their catalytic performance for the synthesis of geranyl acetate
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Special proton-gradient-transfer acid complexes (PGTACs) in which the bonded protons are not equivalent and have gradients in transfer ability, acidity, and reactivity were reported. The acidity gradient of the protons gave the PGTACs excellent catalytic activity and selectivity in the esterification of terpenols. These PGTACs are “reaction-induced self-separation catalysts” and can be easily reused. The kinetics with PGTACs as catalyst in the esterification of geraniol were also studied for use in engineering design.
- Chen, Yongle,Ding, Shiya,Zheng, Wentao,Zhang, Yiyang,Wu, Youting,Hu, Xingbang
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p. 2114 - 2121
(2017/01/16)
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- Graphite oxide-catalyzed acetylation of alcohols and phenols
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Graphite oxide (GO) was used as a catalyst for the reactions of alcohols and phenols with acetic anhydride. The acetates of primary and secondary alcohols were prepared in good to excellent yields in short reaction time under mild conditions. Electron deficient phenols could be converted to the corresponding acetates steadily. As an efficient catalyst, GO is easily available, cheap, moderately toxic and weakly acidic.
- Liu, Yuan-Yuan,Qi, Jun-Mei,Bai, Li-Sha,Xu, Yue-Long,Ma, Ning,Sun, Fei-Fei
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supporting information
p. 726 - 730
(2016/05/19)
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- A process for the preparation of acetate
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The invention relates to an acetate preparation method. The method comprises the following steps: carrying out a contact reaction of sec-butyl acetate and alcohol in the presence of an ester exchange catalyst under an ester exchange reaction condition, adding products obtained after the contact reaction into a separation tower, controlling the tower top temperature to separate unreacted sec-butyl acetate and sec-butyl alcohol generated after the reaction from the tower top, and carrying out normal-pressure or reduced-pressure flash evaporation to separate acetate generated after the reaction from a tower bottom fraction, wherein the alcohol is alcohol having a general formula of R(OH)n and/or polyol alkylether having at least one hydroxy group, R is a C5-C20 n-valence alkyl group, a C5-C20 n-valence alkenyl group, a C5-C12 n-valence cycloalkyl group or a C7-C20 n-valence aryl group, and n is an integer in a range of 1-5. The method has the advantages of high conversion rate of the alcohol as a reaction raw material, and high acetate selectivity.
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Paragraph 0035; 0036; 0037; 0038
(2017/01/26)
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- Synthesis and characterization of ionic liquid immobilized on magnetic nanoparticles: A recyclable heterogeneous organocatalyst for the acetylation of alcohols
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Herein, we describe a simple and efficient procedure for the preparation of 3-((3-(trisilyloxy)propyl)propionamide)-1-methylimidazolium chloride ionic liquid supported on magnetic nanoparticle (TPPA-IL-Fe3O4). The structure of this magnetic ionic liquid is fully characterized by FT-IR, TGA, XRD, VSM, SEM, EDX and DLS techniques. TPPA-IL-Fe3O4 is employed as a catalyst for the acetylation of alcohols with acetic anhydride under mild and heterogeneous conditions at room temperature with good to excellent yields. The magnetic catalyst could be readily separate from the reaction media by simple magnetic decantation, and reused several times without significant loss of its catalytic activity.
- Ghorbani-Choghamarani, Arash,Norouzi, Masoomeh
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p. 832 - 840
(2015/11/16)
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- Synthesis of lipase nano-bio-conjugates as an efficient biocatalyst: Characterization and activity-stability studies with potential biocatalytic applications
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In the present study, we have synthesized lipase-nano-bio-conjugates via immobilization of various lipases on multiwall carbon nano-tubes (MCNT), in order to construct an efficient and recyclable biocatalytic system. In a screening study lipase Pseudomonas fluorescens (PFL) acted as an efficient biocatalyst (lipase-nano-bio-conjugates) which showed higher retention of lipase activity and protein loading. Consequently the immobilization support : lipase (MCNT : PFL) composition was screened in which MCNT : PFL (2 : 1) was calculated as a robust biocatalyst composition which showed higher activity retention and protein loading. This nano-bio-conjugate was then characterized in detail with physical and biochemical techniques using SEM, TEM, FTIR, Km, Vmax, catalytic efficiency and (%) water content analysis. This developed biocatalyst was further used for practical biocatalytic applications such as O-acylation reactions. Various reaction parameters were optimized in detail like reactant molar ratio (2 : 3.5), solvent, MCNT : PFL biocatalyst amount (36 mg), temperature (50°C) etc. The developed biocatalytic protocol was then extended to synthesize several (twenty-two) industrially important acylated moieties with an excellent yield, these products are well characterized by 1HNMR, 13CNMR and GCMS analysis. Moreover in the present study, we have reviewed the potential industrial applications of various synthesized compounds. Also, we have studied the thermodynamic aspect which demonstrated more feasibility of use of immobilized MCNT : PFL lipase over free lipase. Interestingly, immobilized MCNT : PFL lipase showed 2.3 fold higher catalytic activity than free PFL. Besides this, the biocatalyst was efficiently recycled for up to five cycles. Thus the present protocol demonstrated, (i) synthesis of nano-bio-conjugates as a bio-catalyst, (ii) detailed physical-biochemical characterization of nano-bio-conjugates, (iii) optimization of the biocatalytic protocol (iv) practical biocatalytic applications along with a mechanistic study (v) a thermodynamic feasibility study and (vi) recyclability study. 2015
- Badgujar, Kirtikumar Chandulal,Sasaki, Takehiko,Bhanage, Bhalchandra Mahadeo
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p. 55238 - 55251
(2015/07/07)
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- Liquid carbon dioxide as an effective solvent for immobilized Candida antarctica lipase B catalyzed transesterification
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The transesterification of alcohols catalyzed by immobilized Candida antarctica lipase B (Novozym 435) was found to be effectively enhanced using a liquid CO2 medium when it was compared with that using organic solvents. The large-scale kinetic-resolution of secondary alcohol by the immobilized lipase was also successfully performed with a continuous packed-column reactor that stably afforded corresponding enantiopure products. Herein, liquid CO2 was proved for the first time to be superior to conventional organic solvents for biotransformation.
- Hoang, Hai Nam,Matsuda, Tomoko
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p. 639 - 641
(2015/02/19)
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- Sulfonic acid-functionalized periodic mesoporous organosilicas in esterification and selective acylation reactions
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The application of sulfonic acid-functionalized periodic mesoporous organosilicas (PMOs) having either phenyl (1a) or ethyl (1b) bridging groups was investigated in the esterification of a variety of alcohols and fatty acids. It was found that 1b consistently exhibited higher catalytic performance than 1a in the described reaction. In particular, it was proposed that the superior catalytic activity of 1b in esterification of fatty acids with methanol is a result of adequate hydrophobic-hydrophilic surface balance in the ethyl PMO catalyst. In addition, the study of chemoselective acylation of 1,3-butanediol with dodecanoic acid with varied mesoporous silica-supported solid sulfonic acids including both 1a and 1b implies that there is a compromise between the reaction selectivity and the surface physicochemical properties of the employed catalyst. Our results clearly show that the catalyst having high surface hydrophilic nature gives high selectivity toward the formation of mono-acylated products whereas those with relatively high hydrophobic characteristics showed enhanced selectivity toward the formation of di-acylated products.
- Karimi, Babak,Mirzaei, Hamid M.,Mobaraki, Akbar,Vali, Hojatollah
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p. 3624 - 3631
(2015/07/01)
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- Catalytic Aerobic Oxidation of Arylhydrazides with Iron Phthalocyanine
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A convenient method for the synthesis of 2-arylazocarboxylates from 2-arylhydrazinecarboxylates by aerobic oxidation with iron phthalocyanine is described. The reaction is applicable to oxidative activation of 1-acyl-2-phenylhydrazines. Some preliminary experiments suggest Michaelis-Menten kinetics and participation of radical species in the reaction mechanism.
- Hashimoto, Takuma,Hirose, Daisuke,Taniguchi, Tsuyoshi
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supporting information
p. 3346 - 3352
(2015/11/03)
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- Thermodynamically leveraged tandem catalysis for ester RC(O)O-R′ bond hydrogenolysis. scope and mechanism
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Rapid and selective formal hydrogenolysis of aliphatic ester RC(O)O-R′ linkages is achieved by a tandem homogeneous metal triflate + supported palladium catalytic system. The triflate catalyzes the mildly exothermic, turnover-limiting O-R′ cleavage process, whereas the exothermic hydrogenation of the intermediate alkene further drives the overall reaction to completion.
- Lohr, Tracy L.,Li, Zhi,Assary, Rajeev S.,Curtiss, Larry A.,Marks, Tobin J.
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p. 3675 - 3679
(2015/06/16)
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- Polystyrene trimethyl ammonium chloride impregnated Rh(0) (Rh@PMe3NCl) as a catalyst and methylating agent for esterification of alcohols through selective oxidation of methanol
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Rhodium(0) nanoparticle (NP)-impregnated polystyrene trimethyl ammonium chloride (PMe3NCl) resin (Rh@PMe3NCl) under basic conditions acts as a cross-dehydrogenative coupling-methylating (CDCM) agent for the selective oxidation of methanol and its in situ reaction with benzyl/alkyl alcohols allowing methyl group transfer for acetate ester synthesis in a tandem approach. The redox property of methanol which restricts the oxidation of benzyl/alkyl alcohols for product formation is critically investigated.
- Guha, Nitul Ranjan,Bhattacherjee, Dhananjay,Das, Pralay
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p. 2575 - 2580
(2015/06/30)
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