cas 141-12-8, NERYL ACETATE | Articles data

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Epoxy-Tethered Diels-Alder Reaction toward the Tricyclic Core of Kalihinols
A chiral-template-driven intramolecular Diels-Alder reaction has been used to build the tricyclic core of kalihinols, a group of antimalarial marine natural products. The key starting materials are commercially available nerol and sulcatone.
Krishna Chaitanya, Nandikolla,Dinda, Shrabani,Mainkar, Prathama S.,Chandrasekhar, Srivari
p. 3557 - 3560
(2020)
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Synthetic studies on the DEF-rings of FR182877 and hexacyclinic acid
A synthesis of model DEF-rings of the polyketide anti tumor natural products FR182877 and hexacyclinic acid has been achieved. The key steps in the synthesis are an intramolecular Pd(0) catalyzed allylic substitution reaction, which was used to generate a 9-membered carbocycle, and a novel transannular iodocyclization reaction which furnished the DF-rings of both natural products.
Clarke, Paul A.,Grist, Matthew,Ebden, Mark,Wilson, Claire,Blake, Alexander J.
p. 353 - 363
(2005)
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Synthesis of a model DEF-ring core of hexacyclinic acid
The first synthesis of a DEF-ring system of hexacyclinic acid is reported. The key steps being an intramolecular Pd(0) π-allyl substitution reaction, followed by a transannular iodocyclisation with acetyl hypoiodite.
Clarke, Paul A.,Grist, Matthew,Ebden, Mark,Wilson, Claire
p. 1560 - 1561
(2003)
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Iridoid Sex Pheromone Biosynthesis in Aphids Mimics Iridoid-Producing Plants
Biosynthesis of (1R,4aS,7S,7aR)-nepetalactol (1) and (4aS,7S,7aR)-nepetalactone (2) in plants involves iridoid synthase (ISY), an atypical reductive cyclase that catalyses the reduction of 8-oxogeranial into the reactive enol of (S)-8-oxocitronellal, and cyclization of this enol intermediate, either non-enzymatically or by a nepetalactol-related short chain dehydrogenase enzyme (NEPS) that yields the nepetalactols. In this study, we investigated the biosynthesis in vivo of 1 and 2 in the pea aphid, Acyrthosiphon pisum, using a library of isotopically-labelled monoterpenoids as molecular probes. Topical application of deuterium-labelled probes synthesized from geraniol and nerol resulted in production of 2H4?lactol 1 and 2H4?lactone 2. However, deuterium incorporation was not evident using labelled probes synthesized from (S)-citronellol. These results suggest that iridoid biosynthesis in animals, specifically aphids, may follow a broadly similar route to that characterised for plants.
Partridge, Suzanne J.,Withall, David M.,Caulfield, John C.,Pickett, John A.,Stockman, Robert A.,Oldham, Neil J.,Birkett, Michael A.
supporting information
p. 7231 - 7234
(2021/04/21)

New neryl esters from Helichrysum italicum (Roth) G. Don (Asteraceae) essential oil
Helichrysum italicum (immortelle) is a dwarf aromatic shrub native to the Mediterranean region. The typical subspecies (italicum) produces an essential oil rich in neryl acetate and characteristic β-diketones, italidiones, highly valued in the perfume industry. As esters are an important group of aroma-active volatiles, herein the composition of the ester fraction of this immortelle chemotype essential oil was studied in detail. Chromatographic separation of Corsican immortelle essential oil enabled the discovery of numerous potentially olfactory-interesting esters of nerol and/or angelic acid, undetectable by direct GC-MS analyses of the unfractioned oil. Four esters of nerol and medium-chain branched fatty acids represent new natural products, while several other esters have a rather restricted occurrence in the Plant Kingdom.
?or?evi?, Miljana R.,?ivkovi? Sto?i?, Milena Z.,Aksi?, Jelena M.,Gen?i?, Marija S.,Mladenovi?, Marko Z.,Radulovi?, Niko S.
supporting information

(2020/11/02)

Total Synthesis of Isohericenone J via a Stille Coupling Reaction
The first total synthesis of isohericenone J is reported. Key features of this synthetic strategy are a Friedel-Crafts reaction to construct the isobenzofuranone unit and a Pd-catalyzed Stille coupling reaction for the formation of the C5-C1′ bond, generating the natural product, as well as one of its isomers, in 6.0% overall yield in eight steps. This strategy provides a foundation for the synthesis of challenging isobenzofuranone and isoindolinone-type derivatives.
Cao, Wei,Chen, Ping,Tang, Yu
p. 1701 - 1705
(2020/06/08)

Method for synthesizing acetate perfume
The invention provides a method for synthesizing acetate by alcohol esterification, which comprises the following steps: by using enol acetate as an esterification reagent, esterifying a primary alcohol, secondary alcohol or tertiary alcohol substrate at high selectivity and high yield under the action of an acidic catalyst to obtain the corresponding acetate products. The method has the main advantages that the synthesis method is novel, enol acetate is used as an esterification reagent, reaction byproducts are micromolecular acetaldehyde or acetone and the like, and the micromolecular compounds do not show acidity and are low in boiling point, so that rearrangement side reaction of an alcohol substrate cannot be caused; and the small molecule byproduct can be conveniently removed from the reaction solution, so that the esterification reaction is promoted to be completely carried out, the reaction stability is good, and the yield is high.
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Paragraph 0060-0062

(2021/01/15)

Preparing method and application of aminopyridine derivative
The invention provides an aminopyridine derivative and a preparing method and application thereof. The structural formula of the aminopyridine derivative is shown in the description, wherein R represents substitute groups and is selected from one or more of alkyl groups of C1-C20, phenyl groups, naphthyls, methoxy groups, benzyloxy groups, fluorine, chlorine, bromine, trifluoromethyl, methoxycarbonyl groups. The preparing method comprises the steps of conducting benzylation on 4-aminopyridine and benzylic halides under action of an alkaline reagent. The aminopyridine derivative is used for catalyzing esterification reaction, and is especially suitable for catalyzing acetic acid esterification reaction with alcohol as the substrate; the reaction speed is high, the yield is high, and the reaction effect and the reaction speed are almost equal to those of 4-dimethylamino pyridine. The aminopyridine derivative has large molecular weight and a high boiling point and accordingly can be separated from primary products and auxiliary products through distillation or rectification and can be reused cyclically ten times or more, the cost of the catalyst is greatly reduced, and the aminopyridine derivative has good industrial application prospects.
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Paragraph 0101-0103; 0113

(2019/07/16)

Manganese-mediated acetylation of alcohols, phenols, thiols, and amines utilizing acetic anhydride
Manganese(II) chloride-catalyzed acetylation of alcohols, phenols thiols and amines with acetic anhydride is reported. This method is environment-friendly and economically viable as it involves inexpensive, relatively benign catalyst, mild reaction condition, and simple workup. Acetylation is performed under the solvent-free condition at ambient temperature and acetylated products obtained in good to excellent yields. Primary, secondary heterocyclic amines, and phenols with various functional groups are smoothly acetylated in good yields. This method exhibits exquisite chemoselectivity, the amino group is preferentially acetylated in the presence of a hydroxyl/thiol group.
Jain, Isha,Sharma, Ramandeep,Malik, Payal
supporting information
p. 2952 - 2960
(2019/09/13)

PREPARATION OF ACETATE COMPOUNDS VIA A KETENE COMPOUND
The present invention relates to a method for preparing acetate compounds using ketene.
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Page/Page column 20

(2019/07/13)

Lipase-mediated selective acetylation of primary alcohols in ethyl acetate
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.
supporting information
p. 287 - 290
(2017/12/29)

MANUFACTURING METHOD OF CARBOXYLIC ACID PRENYL AND PRENOL USING OXOVANADIUM COMPLEX
PROBLEM TO BE SOLVED: To provide an industrially and economically advantageous manufacturing method of carboxylic acid prenyl and prenol in a high yield under a mild condition. SOLUTION: In a manufacturing method, allyl alcohol represented by the formula (1) is reacted with carboxylic acid anhydride represented by the formula (2) in a presence of an oxovanadium complex prepared by reacting trialkoxy oxovanadium and a pyridinecarboxylic acid derivative, thereby obtaining allyl ester represented by the formula (3). Further, carboxylic acid prenyl is subjected to solvolysis, thereby obtaining prenol represented by the formula (4). SELECTED DRAWING: None COPYRIGHT: (C)2017,JPO&INPIT
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Paragraph 0069

(2017/10/07)

Unravelling transition metal-catalyzed terpenic alcohol esterification: A straightforward process for the synthesis of fragrances
Iron nitrate is a simple and commercially available Lewis acid and is demonstrated to be able to catalyze β-citronellol esterification with acetic acid, achieving high conversion and ester selectivity (ca. 80 and 70%, respectively), within shorter reaction times than those reported in the literature. To the best of our knowledge, this is the first report of a terpenic alcohol esterification reaction catalyzed by Fe(NO3)3. This process is an attractive alternative to the slow and expensive enzymatic processes commonly used in terpenic alcohol esterification. Moreover, it avoids the undesirable steps of neutralizing the products, which are always required in mineral acid-catalyzed reactions. We have performed a study of the activity of different metal Lewis acid catalysts, and found that their efficiency is directly linked to the ability of the metal cation to generate H+ ions from acetic acid ionization. The measurement of pH as well as the conversions achieved in the reactions allowed us to obtain the following trend: Fe(NO3)3 > Al(NO3)3 > Cu(NO3)2 > Ni(NO3)2 > Zn(NO3)2 > Mn(NO3)2 > Co(NO3)2 > LiNO3. The first three are recognized as stronger Lewis acids and they generate more acidic solutions. When we carried out reactions with different iron salts, it was possible to conclude that the type of anion affects the solubility of the catalyst, as well as the conversion and selectivity of the process. Fe2(SO4)3 and FeSO4 were insoluble and less active. Conversely, though they were equally soluble, Fe(NO3)3 was more selective for the formation of β-citronellyl acetate than FeCl3. We assessed the effects of the main reaction variables such as reactant stoichiometry, temperature, and catalyst concentration. In addition to citronellol, we investigated the efficiency of the iron(iii) catalyst in the solvent free esterification of several terpenic alcohols (geraniol, nerol, linalool, α-terpineol) as well as other carboxylic acids.
Da Silva,Ayala
p. 3197 - 3207
(2016/05/24)

Heteropoly acid catalysts for the synthesis of fragrance compounds from bio-renewables: Acetylation of nopol and terpenic alcohols
The cesium salt of tungstophosphoric heteropoly acid, Cs2.5H0.5PW12O40, is an active and environmentally friendly heterogeneous catalyst for the liquid-phase acetylation of nopol and several biomass-derived terpenic alcohols (i.e., α-terpineol, nerol, geraniol, linalool, menthol, isoborneol, perillyl alcohol, carveol, isopulegol, carvacrol and nerolidol) with acetic anhydride. The resulting flavor and fragrance acetic esters, which are widely used in perfumery, household and food products, are obtained in good to excellent yields. The reactions occur at room temperature with low catalyst loadings without substantial catalyst leaching and can be performed with stoichiometric amounts of an acetylating agent in solvent free systems.
Costa, Vinicius V.,Da Silva Rocha, Kelly A.,Oliveira, Luiz C. A.,Kozhevnikova, Elena F.,Kozhevnikov, Ivan V.,Gusevskaya, Elena V.
p. 43217 - 43222
(2016/05/24)

METHOD FOR PRODUCING PRENYL ESTERS AND PRENOLS
PROBLEM TO BE SOLVED: To provide an industrially and economically advantageous method for geometrically selectively producing prenol under a mild condition. SOLUTION: Provided is a method for producing prenyl ester (3) in which allyl alcohol (1) is reacted with vinyl ester (2) under the presence of an oxovanadium complex and a hydrolytic enzyme. Further provided is a method for producing prenol (4) by hydrolyzing prenyl ester (3). SELECTED DRAWING: None COPYRIGHT: (C)2017,JPOandINPIT
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Paragraph 0080

(2017/01/17)

Green bioprocesses in sponge-like ionic liquids
Abstract Ionic liquids (ILs) are a new class of liquid solvent, whose use has led to a green chemical revolution because of their unique array of physico-chemical properties, headed by their negligible vapour pressure and their exceptional ability to stabilize biocatalysts. Hydrophobic ILs based on cations with long alkyl side-chains, e.g. N,N,N,N-hexadecyltrimethylammonium bis(trifluoromethylsulfonyl)imide ([C16tma][NTf2]), are temperature switchable ionic liquid/solid phases that behave as sponge-like systems (sponge-like ionic liquid, SLILs). Based on this new property, SLILs have been used to develop straightforward and clean approaches for producing nearly pure synthetic compounds with added value (e.g. geranyl acetate, anisyl acetate, methyl oleate, etc.) in two steps: an enzymatic synthetic step as liquid phase, and then a product separation step involving simple centrifugation as a solid phase.
Lozano, Pedro,Bernal, Juana M.,Gómez, Celia,García-Verdugo, Eduardo,Isabel Burguete,Sánchez, Gregorio,Vaultier, Michel,Luis, Santiago V.
p. 54 - 59
(2015/08/06)

Ligand-controlled regiodivergent Ni-catalyzed reductive carboxylation of allyl esters with CO2
A novel Ni-catalyzed regiodivergent reductive carboxylation of allyl esters with CO2 has been developed. This mild, user-friendly, and operationally simple method is characterized by an exquisite selectivity profile that is dictated by the ligand backbone.
Moragas, Toni,Cornella, Josep,Martin, Ruben
supporting information
p. 17702 - 17705
(2015/02/19)

Selective allylic hydroxylation of acyclic terpenoids by CYP154E1 from Thermobifida fusca YX
Allylic alcohols are valuable precursors in the synthesis of pharmaceutical intermediates, agrochemicals and natural products. Regioselective oxidation of parental alkenes is a challenging task for chemical catalysts and requires several steps including protection and deprotection. Many cytochrome P450 enzymes are known to catalyse selective allylic hydroxylation under mild conditions. Here, we describe CYP154E1 from Thermobifida fusca YX that enables this type of oxidation. Several acyclic terpenoids were tested as possible substrates for CYP154E1, and the regio- and chemoselectivity of their oxidation was investigated. Using a previously established bioinformatics approach we identified position 286 in the active site of CYP154E1 which is putatively involved in substrate binding and thereby might have an effect on enzyme selectivity. To tune regio- and chemoselectivity of the enzyme three mutants at position 286 were constructed and used for substrate oxidation. All formed products were analysed with GC-MS and identified using chemically synthesised authentic samples and known compounds as references. Best regioselectivity towards geraniol and nerol was observed with the wild type enzyme mainly leading to 8-hydroxy derivatives (8-hydroxygeraniol or 8-hydroxynerol) with high selectivity (100% and 96% respectively). Highest selectivities during the oxidation of geranylacetone and nerylacetone were observed with the following variants: V286F led mainly to 7-hydroxygeranylacetone (60% of the total product) and V286A produced predominantly 12-hydroxynerylacetone (75% of total product). Thus, CYP154E1 and its mutants expand the tool-box for allylic hydroxylation in synthetic chemistry.
Bogazkaya, Anna M.,Von Buehler, Clemens J.,Kriening, Sebastian,Busch, Alexandrine,Seifert, Alexander,Pleiss, Juergen,Laschat, Sabine,Urlacher, Vlada B.
supporting information
p. 1347 - 1353
(2014/07/22)

Effect of acyclic monoterpene alcohols and their derivatives on TRP channels
A series of thirty-six geraniol, nerol, citronellol, geranylamine, and nerylamine derivatives was synthesized and tested on TRPA1, TRPM8, and TRPV1 channels. Most of them acted as strong modulators of TRPA1 channels with EC50 and/or IC50 values 1 μM. None was able to significantly activate TRPM8 channels, while thirteen of them behaved as 'true' TRPM8 antagonists. Little or no effect was generally observed on TRPV1 channels. Some of the compounds examined, that is, compounds 1d,g,n, 2c,d,h,i,o, 3b,e exhibited an appreciable selectivity for TRPA1 subtype.
Ortar, Giorgio,Schiano Moriello, Aniello,Morera, Enrico,Nalli, Marianna,Di Marzo, Vincenzo,De Petrocellis, Luciano
p. 5507 - 5511
(2015/01/08)

Electrogenerated N-heterocyclic carbenes in the room temperature parent ionic liquid as an efficient medium for transesterification/acylation reactions
N-Heterocyclic carbenes (NHCs), generated by electrochemical reduction under galvanostatic control of 1,3-dialkylimidazolium-based ionic liquids, were employed as catalysts in transesterification reactions in the parent, room temperature ionic liquids (RTILs) as solvents, without the utilisation of any volatile organic solvent or base. The reaction between isopropenyl or ethyl acetate and an alcohol (not efficient in the absence of catalyst) was induced by the presence of an electrogenerated NHC, which seems to assist the proton transfer from the alcohol to the ester, yielding the corresponding acetate. The reaction also proceeds with methyl nicotinate as starting ester and 2-(diethylamino)ethanol or benzyl alcohol as alcohols and leads to the corresponding biologically active compounds, nicametate and benzyl nicotinate, in good yields. All products were isolated in good to excellent yields and complete recyclability of the ionic liquid as solvent has been demonstrated.
Chiarotto, Isabella,Feroci, Marta,Sotgiu, Giovanni,Inesi, Achille
supporting information
p. 326 - 331
(2013/02/25)

A clean enzymatic process for producing flavour esters by direct esterification in switchable ionic liquid/solid phases
A clean biocatalytic approach for producing flavour esters using switchable ionic liquid/solid phases as reaction/separation media has been developed. The phase behaviour of different IL/flavour acetyl ester (geranyl acetate, citronellyl acetate, neryl acetate and isoamyl acetate) mixtures was studied at several concentrations, resulting for all cases in fully homogeneous liquid media at 50 °C, and solid systems at room temperature. By using an iterative centrifugation protocol on the solid IL/flavour ester mixtures at controlled temperatures, the solid IL phase and the liquid flavour ester phase can be easily separated. The excellent suitability of an immobilized Candida antarctica lipase B (Novozym 435) catalyst in the esterification reaction between an aliphatic carboxylic acid (acetic, propionic, butyric or valeric) and a flavour alcohol (isoamyl alcohol, nerol, citronellol or geraniol) in N,N′,N′′,N′′′-hexadecyltrimethyl-ammonium bis(trifluoromethylsulfonyl)imide ([C16tma][NTf2])IL has been demonstrated, the product yield being improved up to 100% under appropriate reaction conditions (enzyme amount, dehydrating molecular sieves, etc.) at 50 °C. The enzymatic synthesis of sixteen different flavour esters was carried out in [C16tma][NTf2] by means of this approach, providing products of up to 0.757 g mL-1 concentration after IL separation. The residual activity of the enzyme/IL system during seven consecutive operation cycles was shown to be practically unchanged after reuse.
Lozano, Pedro,Bernal, Juana M.,Navarro, Alicia
p. 3026 - 3033
(2013/01/15)

The synthesis of (Z)-trisubstituted allylic alcohols by the selective 1,4-hydrogenation of dienol esters: Improved synthesis of (-)-β-santalol
(E)-Trisubstituted allylic alcohols are commonly prepared from the corresponding (E)-enals, themselves readily accessible by a simple aldol condensation reaction. We demonstrate that these very same (E)-enals can be converted into (Z)-trisubstituted allylic acetates (and thus alcohols) by a ruthenium-catalyzed 1,4-hydrogenation of the corresponding dienol acetates. This simple solution to a long-lasting problem was applied to an industrially feasible synthesis of (-)-β-santalol.
Fehr, Charles,Magpantay, Iris,Vuagnoux, Magali,Dupau, Philippe
scheme or table
p. 1257 - 1260
(2011/04/16)

Et2SBr.SbCl5Br: An effective reagent for direct bromonium-induced polyene cyclizations
It's all about reactivity: Although bromonium-induced cation-π cyclizations are commonly utilized by nature to fashion six-membered rings from a diverse set of polyene precursors, no general laboratory method exists that can achieve the same breadth of substrate scope. An easily synthesized and handled reagent is described (see scheme) that is capable of directly, broadly, and rapidly effecting such reactions in good yield with a variety of geraniol, farnesol, and nerol derivatives.
Snyder, Scott A.,Treitler, Daniel S.
supporting information; experimental part
p. 7899 - 7903
(2010/04/02)

Fumigant antitermitic activity of plant essential oils and components from ajowan (Trachyspermum ammi), allspice (Pimenta dioica), caraway (Carum carvi), dill (Anethum graveoiens), geranium (Pelargonium graveoiens), and litsea (Litsea cubeba) oils against Japanese termite (Reticulitermes speratus kolbe)
Plant essential oils from 26 plant species were tested for their insecticidal activities against the Japanese termite, Reticulitermes speratus Kolbe, using a fumigation bioassay. Responses varied with source, exposure time, and concentration. Among the essential oils tested, strong insecticidal activity was observed with the essential oils of ajowan (Trachyspermum ammi), allspice (Pimenta dioica), caraway (Carum carvi), dill (Anethum graveoiens), geranium (Pelargonium graveoiens), and litsea (Litsea cubeba). The composition of six essential oils was identified by using gas chromatographymass spectrometry. The compounds thus identified were tested individually for their insecticidal activities against Japanese termites. Responses varied in a dose-dependent manner for each compound. Phenol compounds exhibited the strongest insecticidal activity among the test compounds; furthermore, alcohol and aldehyde groups were more toxic than hydrocarbons. The essential oils and compounds described herein merit further study as potential fumigants for termite control. 2009 American Chemical Society.
Seo, Seon-Mi,Kim, Junheon,Lee, Sang-Gil,Shin, Chang-Hoon,Shin, Sang-Chul,Park, Il-Kwon
experimental part
p. 6596 - 6602
(2010/08/19)

o-benzenedisulfonimide as a soft, efficient, and recyclable catalyst for the acylation of alcohols, phenols, and thiols under solvent-free conditions: Advantages and limitations
o-Benzenedisulfonimide turns out to be a highly efficient Bransted acid catalyst for the acylation of a number of alcohols, phenols, and thiols under a metal- and solvent-free procedure; reaction conditions are mild and yields very good. After the workup, the catalyst can be easily recovered and purified, ready to be reused, with economic and ecological advantages. Georg Thieme Verlag Stuttgart · New York.
Barbero, Margherita,Cadamuro, Silvano,Dughera, Stefano,Venturello, Paolo
scheme or table
p. 3625 - 3632
(2009/07/04)

Synthesis of the macrocyclic core of (-)-pladienolide B
(Chemical Equation Presented) An efficient synthesis of the macrocyclic core of (-)-pladienolide B is disclosed. The concise route relies on a chiral auxiliary-mediated asymmetric aldol addition and an osmium-catalyzed asymmetric dihydroxylation to install the three oxygenated stereocenters of the macrocycle. This purely reagent-controlled and flexible strategy sets the stage for future analogue syntheses and structure-activity relationship plotting of the appealing anticancer lead structure pladienolide B.
Skaanderup, Philip R.,Jensen, Thomas
supporting information; experimental part
p. 2821 - 2824
(2009/05/27)

PROCESS FOR THE ACYLATION OF ORGANIC HYDROXY COMPOUNDS
A process for acylating organic hydroxy compounds, characterized in that the acylation is effected in the presence of a metal oxide which does not carry a catalyst and the use of such metal oxides for acylating organic hydroxy compounds.
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(2008/12/06)

Molecular iodine catalyzed selective acetylation of alcohols with vinyl acetate
Molecular iodine is found to catalyze the acetylation of alcohols efficiently with vinyl acetate. The reaction is mild and selective with good to high yields. Molecular iodine displays significant functional group tolerance, being compatible with methoxy, double bonds, spiroketals, ketals and phenolic hydroxyl functions.
Bosco, J.W. John,Agrahari, Aditya,Saikia, Anil K.
p. 4065 - 4068
(2007/10/03)

Magnesium bistrifluoromethanesulfonimide as a new and efficient acylation catalyst
Magnesium bistrifluoromethanesulfonimide catalyzed the acetylation of phenols, alcohols, and thiols under solvent-free conditions at room temperature and in short times. Electron-deficient and sterically hindered phenols provided excellent yields. The catalyst was found to be general for acylation with other anhydrides, such as propionic, isobutyric, pivalic, chloroacetic, and benzoic anhydrides. The rate of acylation was influenced by the electronic and steric factors associated with the anhydride. The reaction with less electrophilic anhydrides (e.g., chloroacetic and benzoic anhydrides) required higher temperature (～80 °C). Chemoselective acetylation, pivalation, and benzoylation took place with acid-sensitive alcohols without any competitive dehydration/rearrangement.
Chakraborti, Asit K.,Shivani
p. 5785 - 5788
(2007/10/03)

Practical synthesis of allylic silanes from allylic esters and carbamates by stereoselective copper-catalyzed allylic substitution reactions
The first copper-catalyzed allylic substitution reactions of allylic acetates and carbamates employing a bis(triorganosilyl)zinc reagent are reported. This novel procedure avoids the use of stoichiometric amounts of copper salts which are usually mandatory with this chemistry. Application of this methodology to standard model substrates substantiates a high diastereoselectivity for the double bond geometry (E:Z) as well as the relative configuration (syn:anti).
Oestreich, Martin,Auer, Gertrud
p. 637 - 640
(2007/10/03)

PROCESSES FOR SYNTHESIZING ESTERS BY 1,4-ADDITION OF ALKANOIC ACIDS TO MYRCENE OR ISOPRENE
Processes are disclosed for synthesizing esters useful in flavorings and fragrances from ?-pinene, myrcene and/or isoprene. The esters can be used in the manufacture of citral, precursors to citral and other products or precursors such as vitamins, nutritional supplements, flavorings, fragrances and other products. The process includes a 1,4-addition of an alkanoic acid to the conjugated diene of myrcene (which can be generated from ?-pinene) or the conjugated diene of isoprene to produce esters thereof.
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(2008/06/13)

Zirconiuni(IV) chloride as a new, highly efficient, and reusable catalyst for acetylation of phenols, thiols, amines, and alcohols under solvent-free conditions
Zirconium(IV) chloride has been found to be a new, highly efficient, and reusable catalyst for acetylation of structurally diverse phenols, thiols, amines, and alcohols under solvent-free condtions. Acetylation of sterically hindered and electron deficient phenols is achieved in excellent yields with stoichiometric amounts of Ac2O at room temperature. Acid-sensitive alcohols undergo acetylation with excellent chemoselectivity without competitive side reactions such as dehydration or rearrangement. The mild Lewis acid property of the catalyst enables the acetylation to be carried out with optically active substrates without any detrimental effect on the optical purity.
Chakraborti, Asit K.,Gulhane, Rajesh
p. 627 - 630
(2007/10/03)

Copper(II) Tetrafluoroborate-Catalyzed Acetylation of Phenols, Thiols, Alcohols, and Amines
Copper(II) tetrafluoroborate efficiently catalyzes acetylation of structurally diverse phenols, alcohols, thiols, and amines with stoichiometric amounts of Ac2O under solvent-free conditions at room temperature. Acid-sensitive alcohols are smoothly acetylated without competitive side reactions. The reaction is influenced by the steric and electronic factors associated with the substrate as well as the anhydride. Acetylation of a sterically hindered substrate requires excess of anhydride and longer time. Acylation with less electrophilic anhydrides affords poor to moderate yields.
Chakraborti, Asit K.,Gulhane, Rajesh,Shivani
p. 111 - 115
(2007/10/03)

Microwave-assisted NiCl2 promoted acylation of alcohols
A microwave oven acylation of alcohols by carboxylic acid anhydrides has been developed. NiCl2 has been proven an efficient catalyst for the acylation of primary, secondary, and tertiary alcohols and phenols under microwave conditions.
Constantinou-Kokotou, Violetta,Peristeraki, Anna
p. 4227 - 4232
(2007/10/03)

Fluoroboric acid adsorbed on silica gel as a new and efficient catalyst for acylation of phenols, thiols, alcohols, and amines
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
p. 3521 - 3525
(2007/10/03)

Bismuth Oxide Perchlorate as a Highly Efficient Catalyst for Heteroatom Acylation under Solvent-Free Conditions
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
p. 1805 - 1808
(2007/10/03)

Electrostatic catalysis by ionic aggregates: Scope and limitations of Mg(ClO4)2 as acylation catalyst
Alkali and alkaline earth metal perchlorates exhibit electrostatic catalysis in the activation of anhydrides for the acylation reaction. Perchlorates with higher values of the charge-size function of the metal ion exhibit better catalytic activity following the order Mg(ClO4) 2>Ba(ClO4)2>LiClO4. Acylation of structurally diverse phenols, thiols, alcohols, and amines have been carried out with stoichiometric amounts of anhydride at room temperature under solvent free conditions in the presence of catalytic amount of Mg(ClO4) 2. Sterically hindered and electron deficient phenols are efficiently acylated. Acylation with sterically hindered anhydrides such as iso-butyric, pivalic, and benzoic anhydrides are carried out with phenols and alcohols in excellent yields. Acid-sensitive alcohols are acylated in excellent yields without any competitive side reactions.
Chakraborti, Asit K.,Sharma, Lalima,Gulhane, Rajesh,Shivani
p. 7661 - 7668
(2007/10/03)

Lithium perchlorate catalyzed acetylation of alcohols under mild reaction conditions
Lithium perchlorate is found to efficiently catalyze the acetylation of alcohols and phenols with acetic anhydride in good to excellent yields.
Nakae,Kusaki,Sato
p. 1584 - 1586
(2007/10/03)

Conversion of trimethylsilyl ethers to acetyl or formyl esters with TiCl4
A simple method is described for the efficient conversion of trimethylsilyl ethers to their corresponding acetyl and formyl esters in refluxing ethyl acetate or ethyl formate in the presence of TiCl4.
Iranpoor, Nasser,Zeynizadeh, Behzad
p. 2123 - 2128
(2007/10/03)

Enhanced diastereoselectivity in the addition of ester enolate to optically active α,β-epoxyaldehydes obtained from nerol and geraniol
Optically active α,β-epoxyaldehydes obtained from nerol and geraniol were allowed to react with lithium tert-butylacetate. The diastereofacial preference of the aldolisation reaction was always anti ('Si' face attack of the carbonyl). The best diastereoselectivity ever observed in these series (>99: 1 anti:syn) was obtained for the α,β-epoxyneral aldolisation.
Nacro, Kassoum,Baltas, Michel,Escudier, Jean-Marc,Gorrichon, Liliane
p. 9047 - 9056
(2007/10/03)

The aphid sex pheromone cyclopentanoids: Synthesis in the elucidation of structure and biosynthetic pathways
Identification of a range of aphid sex pheromones as comprising the cyclopentanoids (4aS,7S,7aR)-nepetalactone, (1R,4aS,7S,7aR)-nepetalactol and the (1S)- and (1R,4aR,7S,7aS)-nepetalactols required samples authenticated by 1H and 13C NMR. These and related compounds were provided by small scale synthesis and extraction from plants in the genus Nepeta (Lamiaceae). The subsequent discovery that the synthetic sex pheromones could attract males, and also parasitic wasps that attack aphids, has created a need for large scale syntheses of the cyclopentanoids. This is afforded by cyclisation of the 8-oxo-1-enamine of citronellal as originally developed by Schreiber and co-workers (1986). Investigation into the biosynthesis of the cyclopentanoids by plants for exploiting aphid sex pheromones in crop protection by means of molecular biology required synthesis of putative biosynthetic intermediates, some with radioactive isotopic labelling, particularly 8-oxidised monoterpene alcohols and aldehydes.
Dawson, Glenn W.,Pickett, John A.,Smiley, Diane W. M.
p. 351 - 361
(2007/10/03)

COBALT(II) CHLORIDE CATALYSED CONVERSION OF ALLYLIC ALCOHOLS TO REARRANGED ALLYLIC AMIDES
Secondary and tertiary allylic alcohols can be converted to the corresponding allylically rearranged amides and acetates in presence of a catalytic quantity of cobalt(II) chloride and acetic anhydride in acetonitrile.Tertiary alcohols undergo complete rearrangement whereas the secondary ones yield a mixture of regioisomers.
Nayyar, Naresh K.,Reddy, M. Madhava,Iqbal, Javed
p. 6965 - 6968
(2007/10/02)

Highly S(N)2'-, (E)-, and antiselective alkylation of allylic phosphates. Facile synthesis of coenzyme Q10
Treatment of secondary allylic chlorides or allylic phosphates in tetrahydrofuran with prenyl Grignard reagent in the presence of CuCN · 2 LiCl gave geraniol or farnesol derivatives with high S(N)2' selectivity. Phosphate leaving groups were highly transstereoselective for the formation of (E,E)-farnesol derivatives. Furthermore, complete anti-S(N)2' selectivity was observed in the alkylation of optically active allylic phosphates. The present method appears to be an excellent carbon-carbon coupling reaction with high regio-, (E)-, and enantioselectivity. Coenzyme Q10 (ubiquinone 10) was efficiently synthesized using this methodology.
Yanagisawa,Nomura,Noritake,Yamamoto
p. 1130 - 1136
(2007/10/02)

Micellar-Induced Selectivity and Rate Enhancement in the Acid-Catalyzed Cyclization and Rearrangement of Monoterpenes. The Solvolysis of Linalyl and Geranyl Acetates
The monoterpene linalyl acetate (1) undergoes acid-catalyzed solvolysis/cyclization at pH 3 in HCl/citrate buffer to yield three major acyclic alcohols, geranol (2), linalool (3), and nerol (4), and one cyclic alcohol, α-terpineol (5).The acyclic/cyclic alcohol ratio is 2.7 in no sodium dodecyl sulfate (SDS) controls after ca. 3 half-lives, compared to 8.5 when the reaction is carried out in a SDS micelle.No micellar rate effect was observed.The SDS-induced selectivity is explained in terms of the micelle-favoring acyclic conformers of linalyl acetate.In contrast to linalyl acetate, solvolysis of geranyl acetate (6) in the SDS micelle at pH 2 gives little product selectivity but yields a 7-fold rate effect relative to no SDS controls.This rate effect results in very different product distributions after 90percent completion of the reaction.The observed SDS rate effect for geranyl acetate is compatible with a difference in solvolysis mechanism for linalyl and geranyl acetate.
Clark, Benjamin C.,Chamblee, Theresa S.,Iacobucci, Guillermo A.
p. 1032 - 1036
(2007/10/02)

Selective 1,5-Diene Synthesis. A Radical Approach
A new synthetic route to 1,5-dienes is described.Irradiation of a mixture of allyl bromides and allyl sulfides in the presence of hexamethylditin gives the cross-coupled products selectively.
Yanagisawa, Akira,Noritake, Yoshiyuki,Yamamoto, Hisashi
p. 1899 - 1902
(2007/10/02)

A MILD AND STEREOSPECIFIC CONVERSION OF VICINAL DIOLS INTO OLEFINS VIA 2-METHOXY-1,3-DIOXOLANE DERIVATIVES
An efficient and practical method for the stereospecific synthesis of olefins from vicinal diols via the corresponding 2-methoxy-1,3-dioxolanes is reported.
Ando, Masayoshi,Ohhara, Hiroshi,Takase, Kahei
p. 879 - 882
(2007/10/02)

Vakuum UV Photolyses of Some Bichromophoric Alkenes Possesing Hydroxyl or Methoxycarbonyl Group
The direct photolyses at 185 nm of some naturally occuring and related bichromophoric alkenes possesing hydroxyl or methoxycarbonyl group at an allylic, homoallylic, or remote position gave the geometrical isomers as the major photoproducts detectable on gas chromatography.The isomerization yield was highly sensitive to the functional group introduced and its position; allylic alkenols gave poor yields, while both functionalization at a remote position and esterification of the hydroxyl group improve the photoisomerization yield.
Inoue, Yoshihisa,Goan, Kazuyoshi,Hakushi, Tadao
p. 2217 - 2220
(2007/10/02)

Chemical Tranformation of Terpenoids. V. Acidic Conversions of 10-Hydroxygeraniol and 10-Hydroxynerol Derivatives Leading to Cyclic Monoterpenoids
Acid treatment of 1-O-acetyl-10-hydroxygeraniol (5a), 1-O-methyl-10-hydroxygeraniol (5b), 1-O-acetyl-10-hydroxynerol (6a), and 1-O-methyl-10-hydroxynerol (6b) was investigated under various conditions.It was found that treatment of 5a and 6a with HCOOH gave menth-1-ene-8,9-diol (7), while treatment of 5a, 5b, 6a, or 6b with BF3-etherate in CH2Cl2 furnished two menthofuran-type compounds (9, 10) and two bicyclooct-2-ene derivatives (17, 24).Both 9 and 10 were successfully converted to menthofuran (16) and 17 was converted to a bicyclooctenone derivative (23) which was a key intermediate for a synthesis of juvabione (27).Keywords - geraniol; nerol; 10-hydroxygeraniol; 10-hydroxynerol; 10-hydroxygeraniol derivative; 10-hydroxynerol derivative; uroterpenol; menthofuran; bicyclooct-2-ene derivative
Kitagawa, Isao,Tsujii, Shinji,Nishikawa, Fumiko,Shibuya, Hirotaka
p. 2639 - 2651
(2007/10/02)

A New Synthesis of Geranyl Acetate
A new route to geranyl acetate starting from isohexenyl chloride (VIII) and 3,4-dichlorobutan-2-one (IX) is described.The route involves stereoselective reactions giving products with the desired configuration.Preparation of VIII by a new method is also described.
Mathew, K. K.,Raman, P. S.,Antharjanam, T. G. Bhargavi
p. 340 - 342
(2007/10/02)

α-NITRO SULFONES. 2. CONVENIENT NEW SYNTHESIS AND SELECTED FUNCTIONAL GROUP TRANSFORMATIONS
(Phenylsulfonyl)nitromethane (1) is preferentially C-alkylated by benzylic halides and primary alkyl iodides, affording secondary α-nitro sulfone products. α-Nitro sulfones are also obtained from the corresponding C-alkylation of allylic acetates in the presence of catalytic tetrakis(triphenylphosphine)palladium.The palladium(0)-catalyzed reaction is stereospecific for geranyl and neryl acetates and is also regioselective.Desulfonation of α-nitro sulfones is readily accomplished by light-induced reduction with 1-benzyl-1,4-dihydronicotinamide (BNAH).Reduction of secondary α-nitro sulfones with 20percent aqueous titanium(III) chloride affords nitriles.Oxidation with alkaline permanganate affords carboxylic acids.
Wade, Peter A.,Hinney, Harry R.,Amin, Nayan V.,Vail, Peter D.,Morrow, Scott D.,et al.
p. 765 - 770
(2007/10/02)