- Solvent role in the lipase-catalysed esterification of cinnamic acid and derivatives. Optimisation of the biotransformation conditions
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The esterification of cinnamic acid has been deeply investigated using ethanol as nucleophile and Candida antarctica lipase type B (CAL-B) as suitable biocatalyst. Special attention has been paid to the role that the solvent plays in the production of ethyl cinnamate. Therefore, volatile organic solvents and deep eutectic mixtures were employed in order to find optimal reaction conditions. Once that hexane was selected as the solvent of choice, other parameters that affect the enzyme activity were investigated in order to produce ethyl cinnamate with excellent yield. The CAL-B loading, nucleophile equivalents, temperature and reaction time have been identified as key parameters in the enzyme efficiency, and the potential of lipase-catalysed esterification has been finally exploited to produce a series of ethyl esters with different pattern substitutions on the aromatic ring.
- Suárez-Escobedo, Laura,Gotor-Fernández, Vicente
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- Hypervalent iodine(iii) induced oxidative olefination of benzylamines using Wittig reagents
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We have developed hypervalent iodine(iii) induced oxidative olefination of primary and secondary benzylamines using 2C-Wittig reagents, which provides easy access to α,β-unsaturated esters. Mild reaction conditions, good to excellent yields with high (E) selectivity, and a broad substrate scope are the key features of this reaction. We have successfully carried out the gram-scale synthesis of α,β-unsaturated esters.
- Ramavath, Vijayalakshmi,Rupanawar, Bapurao D.,More, Satish G.,Bansode, Ajay H.,Suryavanshi, Gurunath
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p. 8806 - 8813
(2021/05/26)
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- 1,3-Diphenyldisiloxane Enables Additive-Free Redox Recycling Reactions and Catalysis with Triphenylphosphine
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The recently reported chemoselective reduction of phosphine oxides with 1,3-diphenyldisiloxane (DPDS) has opened up the possibility of additive-free phosphine oxide reductions in catalytic systems. Herein we disclose the use of this new reducing agent as an enabler of phosphorus redox recycling in Wittig, Staudinger, and alcohol substitution reactions. DPDS was successfully utilized in ambient-temperature additive-free redox recycling variants of the Wittig olefination, Appel halogenation, and Staudinger reduction. Triphenylphosphine-promoted catalytic recycling reactions were also facilitated by DPDS. Additive-free triphenylphosphine-promoted catalytic Staudinger reductions could even be performed at ambient temperature due to the rapid nature of phosphinimine reduction, for which we characterized kinetic and thermodynamic parameters. These results demonstrate the utility of DPDS as an excellent reducing agent for the development of phosphorus redox recycling reactions.
- Buonomo, Joseph A.,Cole, Malcolm S.,Eiden, Carter G.,Aldrich, Courtney C.
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p. 3583 - 3594
(2020/09/15)
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- Extended architectures constructed of thiourea-modified SBA-15 nanoreactor: A versatile new support for the fabrication of palladium pre-catalyst
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We designed and synthesized a novel catalyst consisting of ordered mesoporous silica (SBA-15) functionalized with bis(thiourea) (BTU) linker. The regular and unique pore channels of BTU-SBA-15 ensure proper control of the size and homogeneous distribution of palladium nanoparticles. The physiochemical properties of the hybrid Pd?BTU-SBA-15 pre-catalyst were investigated using various techniques. The proposed catalyst is found to be very active, reusable, stable and scalable, and has excellent reactivity and selectivity for Suzuki and Heck coupling reactions under very mild and sustainable reaction conditions.
- Alamgholiloo, Hassan,Noroozi Pesyan, Nader,Rostamnia, Sadegh
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- Synthesis of Nitrogen-Containing Goniothalamin Analogues with Higher Cytotoxic Activity and Selectivity against Cancer Cells
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Two series of racemic goniothalamin analogues displaying nitrogen-containing groups were designed and synthesized. A total of 19 novel analogues were evaluated against a panel of four different cancer cell lines, along with the normal prostate cell line PNT2 to determine their selectivity. Among them, goniothalamin chloroacrylamide 13 e displayed the lowest IC50 values for both MCF-7 (0.5 μm) and PC3 (0.3 μm) cells, about 26-fold more potent than goniothalamin (1). Besides its higher potency, compound 13 e also displayed much higher selectivity than goniothalamin. In contrast, goniothalamin isobutyramide 13 c was the most potent analogue against Caco-2 cells (IC50=0.8 μm), about 10-fold more potent and 17-fold more selective than 1. These results reveal the potential of compounds 13 c and 13 e for further in vivo studies, representing the first goniothalamin analogues with IC50 values in the low micromolar range and high selectivity against MCF-7, Caco-2, and PC3 cancer cell lines.
- Meirelles, Matheus A.,Braga, Carolyne B.,Ornelas, Catia,Pilli, Ronaldo A.
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supporting information
p. 1403 - 1417
(2019/08/01)
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- Biocatalytic dynamic kinetic reductive resolution with ketoreductase from: Klebsiella pneumoniae: The asymmetric synthesis of functionalized tetrahydropyrans
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Ketoreductase from growing cells of Klebsiella pneumoniae (NBRC 3319) acts as an efficient reagent for converting racemic α-benzyl/cinnamyl substituted-β-ketoesters to the corresponding β-hydroxy esters with excellent yields and stereoselectivities (ee and de >99 %). The reactions described herein followed a biocatalytic dynamic kinetic reductive resolution (DKRR) pathway, which is reported for the first time with such substrates. It was found that the enzyme system can accept substituted mono-aryl rings with different electronic natures. In addition, it also accepts a substituted naphthyl ring and heteroaryl ring in the α-position of the parent β-ketoester. The synthesized enantiopure β-hydroxy esters were then synthetically manipulated to valuable tetrahydropyran building blocks.
- Barik, Rasmita,Halder, Joydev,Nanda, Samik
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supporting information
p. 8571 - 8588
(2019/10/02)
-
- Gold catalyzed Heck-coupling of arenediazonium o-benzenedisulfonimides
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Diazonium salts, and precisely arenediazonium o-benzenedisulfonimides, have been used for the first time as efficient electrophilic partners in gold catalyzed Heck-coupling reactions. The synthetic protocol was general, easy and gave the target products in satisfactory yields. Mechanistic insights revealed the fundamental roles of the o-benzenedisulfonimide anion as an electron transfer agent thath promotes a radical pathway that does not require the presence of photocatalysts or external oxidants.
- Barbero, Margherita,Dughera, Stefano
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p. 295 - 301
(2018/01/12)
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- Stepwise post-modification immobilization of palladium Schiff-base complex on to the OMS-Cu (BDC) metal–organic framework for Mizoroki-Heck cross-coupling reaction
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Palladium ions were successfully immobilized within the pores of open metal site (OMS) metal organic frameworks (MOFs) with Schiff-base (2-Py-SI) grafted in OMS-Cu (BDC) using the hydrothermal method. This Schiff-base complex on the Cu (BDC) greatly increased catalytic activity and acted as an efficient stabilizer of Pd ions. The hydrothermal method was a more efficient method for generating small metal ions in the MOF structures. The results revealed that the PdII@Cu (BDC)/2-Py-SI is a promising catalyst for the Mizoroki-Heck coupling reaction. The proposed catalyst has better recyclability and can be reused several times without apparent loss of activity.
- Alamgholiloo, Hassan,Rostamnia, Sadegh,Hassankhani, Asadollah,Khalafy, Jabbar,Baradarani, Mehdi M.,Mahmoudi, Ghodrat,Liu, Xiao
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- Catalytic Diastereo- and Enantioselective Fluoroamination of Alkenes
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The stereoselective synthesis of syn-β-fluoroaziridine building blocks via chiral aryl iodide-catalyzed fluorination of allylic amines is reported. The method employs HF-pyridine as a nucleophilic fluoride source together with mCPBA as a stoichiometric oxidant, and affords access to arylethylamine derivatives featuring fluorine-containing stereocenters in high diastereo- and enantioselectivity. Catalyst-controlled diastereoselectivity in the fluorination of chiral allylic amines enabled the preparation of highly enantioenriched 1,3-difluoro-2-amines bearing three contiguous stereocenters. The enantioselective catalytic method was applied successfully to other classes of multifunctional alkene substrates to afford anti-β-fluoropyrrolidines, as well as a variety of 1,2-oxyfluorinated products.
- Mennie, Katrina M.,Banik, Steven M.,Reichert, Elaine C.,Jacobsen, Eric N.
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supporting information
p. 4797 - 4802
(2018/04/17)
-
- Silver-Catalyzed Cross-Olefination of Donor and Acceptor Diazo Compounds: Use of N-Nosylhydrazones as Diazo Surrogate
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The cross-olefination reaction of donor and acceptor diazo compounds was explored. The use of N-nosylhydrazones as diazo surrogates and the dependence on silver catalysis were crucial for the reaction development. A variety of (hetero)aryl N-nosylhydrazones and α-diazo esters, amides, and phosphonates were compatible, and the functionalized alkene products were afforded in good to high yields with moderate (Z)/(E) selectivities. The experimental and DFT calculation results suggest that the cross-selectivity is due to selective activation of the silver catalyst for donor diazo compounds.
- Liu, Zhaohong,Liu, Binbin,Zhao, Xue-Feng,Wu, Yan-Bo,Bi, Xihe
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supporting information
p. 928 - 932
(2017/02/15)
-
- Synthesis of hybrid interfacial silica-based nanospheres composite as a support for ultra-small palladium nanoparticle and application of PdNPs/HSN in Mizoroki-Heck reaction
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The silica based hollow nanosphere (silica-HNS) containing polymer of polyaniline was synthesized and chosen as a promising support for PdNPs. Then it was applied as a green catalyst in the reaction of Heck coupling with high yield. TEM and SEM-EDX/mapping images were used to study the structure and morphology. FT-IR spectroscopy, Thermal gravimetry analysis (TGA), and BET were used to characterize and investigate the catalyst. Also, the amounts of Pd loading were characterized by ICP-AES technique. Catalyst recyclability showed 5 successful runs for the reaction.
- Rostamnia, Sadegh,Kholdi, Saba
-
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- 5,6-dihydropyrrolo[2,1-a]isoquinolines as alternative of new drugs with cytotoxic activity
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In this study, the pyrrolo[2,1-a]isoquinolines 4a–n were synthesized in good yields in a three steps synthesis from the corresponding α,β-unsaturated esters starting materials. These compounds were tested on six human cancer cells lines to measure the cyt
- Chávez-Santos, Rosa María,Torres-Ochoa, Rubén Omar,Ramírez-Apan, María Teresa,Martínez, Roberto,Reyes-Gutiérrez, Paul Eduardo
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p. 973 - 981
(2018/11/02)
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- NOVEL PROCESS FOR THE PREPARATION OF BELINOSTAT
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The present invention provides a novel and commercially viable process with high yield for the preparation of (E)-N-hydroxy-3-(3-phenylsulfamoyl-phenyl)-acrylamide, also known as Belinostat (I). The invention also provides process for purification and nov
- -
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Page/Page column 22; 23
(2017/12/16)
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- N-heterocyclic carbene-catalysed Peterson olefination reaction
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N-heterocyclic carbenes (NHCs) have been utilised as highly efficient organocatalysts to catalyse Peterson olefination reaction of aldehydes with trimethylsilylketene ethyl trimethylsilyl acetal or fluoro(trimethylsilyl)ketene ethyl trimethylsilyl acetal to produce the corresponding functionalized olefines in 34-93% yields with excellent stereoselectivities.
- Wang, Ying,Du, Guang-Fen,Gu, Cheng-Zhi,Xing, Fen,Dai, Bin,He, Lin
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p. 472 - 478
(2015/12/31)
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- Solvent-free, one-pot synthesis of α,β-unsaturated esters in the presence of a C3-symmetric arsine
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An efficient synthesis of α, β-unsaturated esters is achieved via a one-pot reaction in the presence of a C3-symmetric arsine. The key advantages are the short reaction time, simple workup, mild reaction conditions, and high yields.
- Wang, Changqing,Yang, Liu,Zhou, Rong,Mei, Guangquan
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supporting information
p. 1074 - 1079
(2016/07/16)
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- Synthesis of fluorescent molecular probes based on cis-cinnamic acid and molecular imaging of lettuce roots
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We synthesized azo dye- and fluorescence-labeled cis-cinnamic acid analogues possessing inhibitory activity against lettuce root growth and a trans-isomer without bioactivity as a control probe. The radicles incubated with the azo dye-labeled analogue were stained red, with their tips especially deeply dyed. The fluorescent images of the radicles incubated with each of these molecular probes depicted that the root cap was fluorescence-stained. However, images of the control radicles prepared by staining with the trans-isomer fluorescent probe did not show emission at the root cap. These contrasts suggest specific localization of the cis-cinnamate analogue at the columella cells.
- Fukuda, Hiroshi,Nishikawa, Keisuke,Fukunaga, Yukihiro,Okuda, Katsuhiro,Kodama, Kozue,Matsumoto, Kenji,Kano, Arihiro,Shindo, Mitsuru
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supporting information
p. 6492 - 6498
(2016/09/23)
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- Tandem oxidation–Wittig reaction using nanocrystalline barium manganate (BaMnO4); an improved one-pot protocol
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A one-pot, tandem oxidation–Wittig procedure has been developed in which the reacting components are generated in situ from alcohols, triphenyl phosphine, and ethyl bromoacetate using barium manganate as a mild oxidizing agent without the addition of an external base.
- Gholinejad, Mohammad,Firouzabadi, Habib,Bahrami, Maedeh,Nájera, Carmen
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supporting information
p. 3773 - 3775
(2016/07/26)
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- BF3·OEt2-mediated: Syn -selective Meyer-Schuster rearrangement of phenoxy propargyl alcohols for Z -β-aryl-α,β-unsaturated esters
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Synthesis of Z-β-aryl-α,β-unsaturated esters from readily available 1-aryl-3-phenoxy propargyl alcohols is achieved via a BF3-mediated syn-selective Meyer-Schuster rearrangement under ambient conditions. The reaction mechanism is postulated to involve an electrophilic borylation of an allene intermediate as the key step to kinetically control the stereoselectivity.
- Puri, Surendra,Hari Babu, Madala,Sridhar Reddy, Maddi
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p. 7001 - 7009
(2016/07/30)
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- Iron(IV)-Corrole Catalyzed Stereoselective Olefination of Aldehydes with Ethyl Diazoacetate
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Iron(IV)-corrole complexes were first investigated as catalysts for olefination of aldehydes with ethyl diazoacetate in the presence of triphenylphosphine. Efficient olefination of aromatic aldehydes with high trans-selectivity was observed, showing iron corrole is a new kind of promising catalyst for olefination reaction. Transformation of the phosphazine to ylide by iron(IV) corrole was proved to be the key step in the present system.
- Zou, Huai-Bo,Yang, Hong,Liu, Ze-Yu,Mahmood, Mian H.R.,Mei, Guang-Quan,Liu, Hai-Yang,Chang, Chi-Kwong
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supporting information
p. 2791 - 2795
(2015/06/30)
-
- Development of second-generation small-molecule RhoA inhibitors with enhanced water solubility, tissue potency, and significant in vivo efficacy
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RhoA, a member of the Rho GTPases, is involved in a variety of cellular functions and could be a suitable therapeutic target for the treatment of cardiovascular diseases. However, few small-molecule RhoA inhibitors have been reported. Based on our previously reported lead compounds, 32 new 2-substituted quinoline (or quinoxaline) derivatives were synthesized and tested in biological assays. Six compounds showed high RhoA inhibitory activities, with IC50 values of 1.17-1.84 μM. Among these, (E)-3-(3-(ethyl(quinolin-2-yl)amino)phenyl)acrylic acid (26b) and (E)-3-(3-(butyl(quinolin-2-yl)amino)phenyl)acrylic acid (26d) demonstrated noticeable vasorelaxation effects against phenylephrine-induced contraction in thoracic aorta artery rings, and compound 26b had good water solubility and showed significant in vivo efficacy, which was similar to that of 5-(1,4-diazepane-1-sulfonyl)isoquinoline (fasudil) in a subarachnoid hemorrhage-cardiovascular model. To the best of our knowledge, compound 26b is the first example of a small-molecule RhoA inhibitor with potent in vivo efficacy, which could serve as a good lead for designing cardiovascular agents.
- Ma, Sheng,Deng, Jing,Li, Baoli,Li, Xiujiang,Yan, Zhaowei,Zhu, Jin,Chen, Gang,Wang, Zhong,Jiang, Hualiang,Miao, Liyan,Li, Jian
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p. 193 - 206
(2015/03/13)
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- Quantitative Structure-Property Relationship (QSPR) models for a local quantum descriptor: Investigation of the 4- and 3-substituted-cinnamic acid esterification
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In this work, the theoretical description of the 4- and 3-substituted-cinnamic acid esterification with different electron donating and electron withdrawing groups was performed at the B3LYP and M06-2X levels, as a two-step process: the O-protonation and the nucleophile attack by ethanol. In parallel, an experimental work devoted to the synthesis and characterization of the substituted-cinnamate esters has also been performed. In order to quantify the substituents effects, quantitative structure-property relationship (QSPR) models based on the atomic charges, Fukui functions and the Frontier Effective-for-Reaction Molecular Orbitals (FERMO) energies were investigated. In fact, the Fukui functions, f+C and f-O, indicated poor correlations for each individual step, and in contrast with the general literature, the O-protonation step is affected both by the FERMO energies and the O-charges of the carbonyl group. Since the process was shown to not be totally described by either charge- or frontier-orbitals, it is proposed to be frontier-charge-miscere controlled. Moreover, the observed trend for the experimental reaction yields suggests that the electron withdrawing groups favor the reaction and the same was observed for Step 2, which can thus be pointed out as the determining step.
- Rodrigues-Santos, Cláudio E.,Echevarria, Aurea,Sant'Anna, Carlos M.R.,Bitencourt, Thiago B.,Nascimento, Maria G.,Bauerfeldt, Glauco F.
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supporting information
p. 17493 - 17510
(2015/12/01)
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- Ethyl cinnamate derivatives as promising high-efficient acaricides against Psoroptes cuniculi: Synthesis, bioactivity and structure-activity relationship
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This paper reported the synthesis, structure-activity relationship (SAR) and acaricidal activity in vitro against Psoroptes cuniculi, a mange mite, of 25 ethyl cinnamate derivatives. All target compounds were synthesized and elucidated by means of MS, 1H- and 13C-NMR analysis. The results showed that 24 out of 25 tested compounds at 1.0 mg/mL demonstrated acaricidal activity in varying degrees. Among them, 6, 15, 26, 27 and 30 showed significant activity with median lethal concentration values (LC50) of 89.3, 119.0, 39.2, 29.8 and 41.2 μg/mL, respectively, which were 2.1- to 8.3-fold the activity of ivermectin (LC50=247.4 μg/mL), a standard drug in the treatment of Psoroptes cuniculi. Compared with ivermectin, with a median lethal time value (LT50) of 8.9 h, 27 and 30 showed smaller LTM50 values of 7.9 and 1.3 h, respectively, whereas 6, 15 and 26 showed slightly larger LT50 values of 10.6, 11.0 and 10.4 h at 4.5 μmol/mL. SARs showed that the presence of o-NO2 or m-NO2 on the benzene ring significantly improved the activity, whereas the introduction of a hydroxy, methoxy, acetoxy, methylenedioxy, bromo or chloro group reduced the activity. (E)-Cinnamates were more effective than their (Z)-isomer. Nevertheless, the carbon-carbon double bond in the acrylic ester moiety was proven not to be essential to improve the activity of cinnamic acid esters. Thus, the results strongly indicate that cinnamate derivatives, especially their dihydro derivatives, should be promising candidates or lead compounds for the development of novel acaricides for the effective control of animal or human acariasis.
- Zhang, Bingyu,Lv, Chao,Li, Weibo,Cui, Zhiming,Chen, Dongdong,Cao, Fangjun,Miao, Fang,Zhou, Le
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p. 255 - 262
(2015/04/22)
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- Identification of novel phenyl butenonyl C-glycosides with ureidyl and sulfonamidyl moieties as antimalarial agents
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A new series of C-linked phenyl butenonyl glycosides bearing ureidyl(thioureidyl) and sulfonamidyl moieties in the phenyl rings were designed, synthesized, and evaluated for their in vitro antimalarial activities against Plasmodium falciparum 3D7 (CQ sensitive) and K1 (CQ resistant) strains. Among all the compounds screened the C-linked phenyl butenonyl glycosides bearing sulfonamidyl moiety (5a) and ureidyl moiety in the phenyl ring (7d and 8c) showed promising antimalarial activities against both 3D7 and K1 strains with IC50 values in micromolar range and low cytotoxicity offering new HITS for further exploration.
- Ramakrishna, K. Kumar G.,Gunjan, Sarika,Shukla, Akhilesh Kumar,Pasam, Venkata Reddy,Balaramnavar, Vishal M.,Sharma, Abhisheak,Jaiswal, Swati,Lal, Jawahar,Tripathi, Renu,Anubhooti,Ramachandran, Ravishankar,Tripathi, Rama Pati
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supporting information
p. 878 - 883
(2014/09/17)
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- Oxidative alkoxycarbonylation of terminal alkenes with carbazates
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A range of terminal alkenes smoothly underwent palladium-catalyzed oxidative alkoxycarbonylation with carbazates under an oxygen atmosphere to afford structurally diverse α,β-unsaturated esters in moderate to good yields with excellent regioselectivity and E selectivity.
- Su, Yu-Han,Wu, Zhao,Tian, Shi-Kai
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p. 6528 - 6530
(2013/07/26)
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- Catalytic enantioselective dibromination of allylic alcohols
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A new dibromination reaction involving the combination of dibromomalonate as the bromonium source and a titanium bromide species as the bromide source has been developed. Enantioselective catalysis has been achieved through apparent ligand acceleration by a tartaric acid-derived diol.
- Hu, Dennis X.,Shibuya, Grant M.,Burns, Noah Z.
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supporting information
p. 12960 - 12963
(2013/09/24)
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- A newly-designed PE-supported arsine for efficient and practical catalytic Wittig olefination
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A newly designed PE-supported arsine has been developed as an excellent catalyst for catalytic Wittig-type olefination. Simple ketones, in particular inactive ketones prove to be suitable substrates for the first time. This reaction provides an easy access to di-, tri-, and tetra-substituted olefins in high yield.
- Wang, Peng,Liu, Chun-Rong,Sun, Xiu-Li,Chen, Shuai-Shuai,Li, Jun-Fang,Xie, Zuowei,Tang, Yong
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supporting information; experimental part
p. 290 - 292
(2012/01/06)
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- Magnetic nanoparticles-supported palladium: A highly efficient and reusable catalyst for the Suzuki, Sonogashira, and heck reactions
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A highly efficient, air- and moisture-stable and easily recoverable magnetic nanoparticle-supported palladium catalyst has been developed for the Suzuki, Sonogashira and Heck reactions. A wide range of substrates was coupled successfully under aerobic conditions. In particular, the performance of the magnetic separation of the catalyst was very efficient, and it is possible to recover and reuse it at least eight times without significant loss of its catalytic activity. Copyright
- Li, Pinhua,Wang, Lei,Zhang, Lei,Wang, Guan-Wu
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supporting information; experimental part
p. 1307 - 1318
(2012/06/15)
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- Compositions Including 6-Aminohexanoic Acid Derivatives As HDAC Inhibitors
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This invention relates to compounds of Formula (I) wherein Cy1, L1, Y, R1, L2, and Ar2 are defined herein, for the treatment of cancers, inflammatory disorders, and neurological conditions.
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Page/Page column 45
(2012/04/23)
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- Binaphthyl-bridged bis-imidazolinium salts as N-heterocyclic carbene ligand precursors in the palladium-catalyzed Heck reaction
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Two new bis-imidazolinium salts (4a, 4b) have been synthesized as precursors of N-heterocyclic carbenes (NHCs) from the commercially available (R)-2,2′-dihydroxy-1,1′-binaphthalene. The two bis-imidazolinium salts were used as efficient precursor of NHC ancillary ligands in the palladium-catalyzed Heck reaction. Good to excellent yields and high stereoselectivities were obtained with ethyl acrylate, acrylonitrile, and acrylamide as starting materials. The structure of bis-imidazolinium salt 4b was further characterized by single crystal X-ray diffraction analysis. Science China Press and Springer-Verlag Berlin Heidelberg 2011.
- Wu, Hui,Jin, Can,Huang, Guoli,Wang, Lianjun,Jiang, Juli,Wang, Leyong
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experimental part
p. 951 - 956
(2012/02/05)
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- New and facile approach for the synthesis of (E)-α,β-unsaturated esters and ketones
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A general and practical synthesis of (E)-α,β-unsaturated esters and ketones was achieved by the reaction of carbonyl compounds with ethyl-4,4,4-trifluoroacetoacetate and trifluoro-substituted 1,3-diketones in the presence of piperidine in dichloromethane at raoom temperature (≈40°C) with excellent stereoselectivity (see scheme).
- China Raju, Bhimapaka,Suman, Pathi
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supporting information; experimental part
p. 11840 - 11842
(2011/01/12)
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- Exploration of amino-functionalized ionic liquids as ligand and base for heck reaction
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A kind of amino-functionalized ionic liquid has been prepared and investigated as ligand and base for the Heck reactions between aryl iodides and bromides with olefins in the presence of a catalytic amount of Pd submicron powder in [Bmim]PF6. The reaction
- Liu, Jie,Liu, Hongqiang,Wang, Lei
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experimental part
p. 386 - 391
(2010/07/05)
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- Pd-porphyrin functionalized ionic liquid-modified mesoporous SBA-15: An efficient and recyclable catalyst for solvent-free Heck reaction
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The Pd-porphyrin functionalized ionic liquid could be covalently anchored in the channels of mesoporous SBA-15 through ion-pair electrostatic interaction between imidazolium-cationic and Pd-porphyrin-anionic moieties. Such modified SBA-15 materials were prepared successfully via a post-synthesis (surface sol-gel polymerization) or a one-pot sol-gel procedure, which were characterized by powder X-ray diffraction, UV-visible spectroscopy, Fourier transform infrared spectroscopy, N2 sorption, elemental analysis, and transmission electron microscopy. The modified SBA-15 materials are efficient and recyclable catalysts for cross-coupling of aryl iodides or activated aryl bromides with ethyl acrylate without activity loss and Pd leaching even after 9 runs.
- Zhang, Jing,Zhao, Guo-Feng,Popovi?, Zora,Lu, Yong,Liu, Ye
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experimental part
p. 1648 - 1653
(2011/01/11)
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- Ruthenium-catalyzed synthesis of allylic alcohols: Boronic acid as a hydroxide source
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Secondary allylic alcohols were synthesized from linear allylic halides or carbonates using a catalytic amount of a ruthenium complex in the presence of boronic acid. The effects of solvent, base, ruthenium precursor, and boronic acid were fully explored, and the scope of the reaction was extended to various sub-strates. We also describe a preliminary investigation towards an enantioselective process.
- Bouziane, Asmae,Helou, Marion,Carboni, Bertrand,Carreaux, Francois,Demerseman, Bernard,Bruneau, Christian,Renaud, Jean-Luc
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experimental part
p. 5630 - 5637
(2009/05/27)
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- Synthesis of catechins via thiourea/AuCl3-catalyzed cycloalkylation of aryl epoxides
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(Chemical Equation Presented) A diversity-oriented approach for the synthesis of structurally diverse catechins was achieved in good yields via thiourea/AuCl3/AgOTf-catalyzed annulations of aryl epoxides under mild conditions. This new protocol provides a highly efficient entry to a library of catechins-derived natural products, notably anti-HIV agent 8-C-ascorbyl-(-)-epigallocatechin.
- Liu, Yongxiang,Li, Xiben,Lin, Guang,Xiang, Zheng,Xiang, Jing,Zhao, Mingzhe,Chen, Jiahua,Yang, Zhen
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p. 4625 - 4629
(2008/09/20)
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- Highly efficient, recyclable palladium catalyst immobilized on organic-inorganic hybrid material: Application in the heck reaction
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Palladium immobilized on organic-inorganic (silica gel) hybrid materials behaves as a very efficient heterogeneous catalyst in Heck reactions. Iodoarenes, bromoarenes, as well as activated chloroarenes react smoothly with olefins to afford the corresponding cross-coupling products in good to excellent yields under phosphine- and amine-free reaction conditions in the presence of palladium immobilized on 3-[(2-aminoethyl)amino]propyl-functionalized silica gel (Silica-AAPTS-Pd) or palladium immobilized on 3-aminopropyl-functionalized silica gel (Silica-APTS-Pd) as catalyst. The silica-supported palladium catalyst could be recovered and recycled by simple filtration of the reaction solution, and used for more than ten consecutive trials without significant loss of catalytic activity. Georg Thieme Verlag Stuttgart.
- Li, Hongji,Wang, Lei,Li, Pinhua
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p. 1635 - 1642
(2008/02/05)
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- Functionalized ionic liquid as an efficient and recyclable reaction medium for phosphine-free palladium-catalyzed heck reaction
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A functionalized ionic liquid, 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate ([HEmim][BF4]), was found to be as an efficient and recyclable reaction medium for palladium-catalyzed Heck reaction. The olefination of iodoarenes and bromoarenes with olefins generated the corresponding products in good to excellent yields under phosphine-free reaction conditions. The reaction involved the use of [HEmim][BF4] as the solvent, potassium phosphate as the base, and palladium acetate as the catalyst. In addition, palladium and ionic liquid could be recovered and recycled for six consecutive trials without significant loss of its reactivity. Georg Thieme Verlag Stuttgart.
- Zhou, Li,Wang, Lei
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p. 2653 - 2658
(2008/02/05)
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- Tricyclohexylphosphine-cyclopalladated ferrocenylimine complexes: Synthesis, crystal structures and application in Suzuki and Heck reactions
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A series of novel tricyclohexylphosphine (PCy3)-cyclopalladated ferrocenylimine complexes 2c-2g have been easily synthesized. These new palladacycles are thermally stable and are not sensitive to air and moisture. Their detailed structures have been determined by single-crystal X-ray analysis and six different types of intermolecular hydrogen bonds are found to be existed in the crystals of these complexes. The use of 2c-2g as catalysts for Suzuki and Heck reactions was examined. They were found to be very efficient for the Suzuki reaction of aryl chlorides with phenylboronic acid. Typically, using 0.1 mol% of catalyst in the presence of 1.5 equivalent of Cs2CO 3 as base in dioxane at 100 °C provided coupled products in excellent yields. These complexes also displayed good activity in the Heck reaction of a range of aryl bromides with acrylic acid ethyl ester although they were not particularly useful for the activation of aryl chlorides. The Royal Society of Chemistry 2006.
- Xu, Chen,Gong, Jun-Fang,Yue, Su-Fang,Zhu, Yu,Wu, Yang-Jie
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p. 4730 - 4739
(2007/10/03)
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- A versatile approach toward the ansamycin antibiotics
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The ansamycin antibiotics contain metacyclophanic macrolactams, many of which possess potent antitumor activity. Only a few total syntheses of this family of natural products have been reported, and modifications to increase potency have not been describe
- Peng, Weimin,Blagg, Brian S. J.
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p. 975 - 978
(2007/10/03)
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- Anti-inflammatory medicaments
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Novel compounds and methods of using those compounds for the treatment of inflammatory conditions are provided. In a preferred embodiment, modulation of the activation state of p38 kinase protein comprises the step of contacting the kinase protein with the novel compounds.
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- Fused imidazopyridine derivatives as antihyperlipidemic agents
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A novel compound of the formula: wherein ring Q is an optionally substituted pyridine ring; One of R0, R1and R2is —Y0—Z0, and the other tow groups are a hydrogen, a halogen, an optionally substituted hydroxy group, a hydrocarbon group that may be an optionally substituted hydrocarbon group or an acyl group; Y0is a bond or an optionally substituted bivalent hydrocarbon group; Z0is a basic group which may be bonded via oxygen, nitrogen, —CO—, —CS—, —SO2N(R3)— (where R3is hydrogen or an optionally substituted hydrocarbon group), or S(O)n(wherein n is to 0, 1 or 2); .........is a single bond or a double bond, or a salt thereof, which has an excellent LDL receptor up-regulating, blood-lipids lowering, blood-sugar lowering and diabetic complication-ameliorating activity.
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- A fast and mild method for the nitration of aromatic rings
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The use of N2O5 and a Fe(III) catalyst for the nitration of aromatic rings is described. This methodology is compatible with most functional groups and results in near quantitative yields in 4 min. The reaction conditions are non-oxidising: benzaldehyde and benzyl alcohols are readily nitrated with little or no oxidation (4%) occurring. The addition of the iron catalyst activates the system to such an extent that nitration of an activated aromatic ring, such as toluene, occurs quantitatively at -100°C. This high activity allows compounds with sensitive functional groups such as alkenes to be smoothly nitrated.
- Bak, Radoslaw R.,Smallridge, Andrew J.
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p. 6767 - 6769
(2007/10/03)
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- Addition of silyl ketene acetals to nitrones catalyzed by lanthanide triflates
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α-Aryl-N-phenyl nitrones reacted with silyl ketene acetals mediated by lanthanum trifloromethanesulfonate (triflate) to afford the addition product in excellent yield under mild conditions. α-Aryl-N-tert-butyl nitrone reacted with ethyl trimethylsilylacetate to yield the unexpected α,β-unsaturated ester in a 100% E-form. A possible mechanism for the process is discussed. (C) 2000 Elsevier Science Ltd.
- Qian, Changtao,Wang, Longcheng
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p. 7193 - 7197
(2007/10/03)
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- N-phenyl-N-acetamidoglycinamides, their preparation and medicaments containing them
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Compounds of formula: STR1 in which R1 represents a hydrogen atom or an alkyl, alkoxycarbonyl or an unsubstituted or substituted phenyl radical, R2 represents a hydrogen atom or an unsubstituted or substituted alkyl radical, R3 represents an alkyl, phenylalkyl, indanyl, cycloalkylalkyl or an unsubstituted or substituted phenyl radical, or R2 and R3 form a heterocycle together with the nitrogen atom to which they are attached, and R4 represents an unsubstituted or substituted phenyl radical, a naphthyl, indolyl or quinolyl radical or a phenylamino radical in which the phenyl ring is unsubstituted or substituted, their preparation and medicaments containing them.
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- The Wittig reaction of stable ylide with aldehyde under microwave irradiation: Synthesis of ethyl cinnamates
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The Wittig reaction of stable ylide, triphenyl-carbethoxymethylene phoshorane, with aldehydes was performed within 5-6 minutes under microwave irradiation. Remarkable rate enhancements and dramatic reductions of reaction times have been observed. Thus, the Wittig reaction of stable ylide with aldehyde is optimized.
- Xu,Chen,Fu,Huang
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p. 2229 - 2233
(2007/10/02)
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- Reaction of phenyl- and alkoxycarbonylmethanesulfonyl fluoride with activated haloalkanes
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Arylmethanesulfonyl fluorides condense with α-bromoketones by attacking at the methylenyl carbon instead of the carbonyl bond to give α,β-conjugated ketones.They also condense with other activated haloalkanes in a similar manner.The preparation of FSO2CH2R (R = CO2Me, CO2Et, CN) is described.Fluorosulfonyl acetate reacts with the carbonyl bonds of aldehydes to give alkenes, whereas it attacks the phenacyl bromide exclusively at the α-carbon.The reaction mode of these sulfonyl fluorides is discussed on the basis of kinetic data. Key words: α-Fluorosulfonylcarbanions; α,β-conjugated ketone; α,β-conjugated ester; alkene formations.
- Kagabu, S.,Shimizu, C.,Takahashi, J.,Hara, K.,Koketsu, M.,Ishida, M.
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p. 435 - 439
(2007/10/02)
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- Ba(OH)2 AS CATALYST IN ORGANIC REACTIONS - PART XIX - STRUCTURE-CATALYTIC ACTIVITY RELATIONSHIP IN THE AdN OF SEVERAL YLIDS TO CH=O GROUP, CATALYZED BY ACTIVATED BARIUM HYDROXIDE CATALYST
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The reactivity of several products R1R2CH-X(1+), 1, (X=N,P,S), which can produce ylids by reaction with bases, has been tested using the activated barium hydroxide catalysts, C-200.Wittig-Horner, Wittig, Corey-Chaykovsky and Kroehnke type reactions have been analyzed.The pKa of 1, and the structure of active sites control the process.When 1 has a strong acid character, the process takes place - dissolving the solid - in homogeneous phase.When 1, has pKa values 11.7), that control the reaction mechanism and the reactivity of adsorbed ylids.
- Sinisterra, J. V.,Marinas, J. M.,Riquelme, F.,Arias, M. S.
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p. 1431 - 1440
(2007/10/02)
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- Barium Hydroxide as Catalyst in Organic Reactions; V. Application in the Horner Reaction under Solid-Liquid Phase-Transfer Conditions
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A new application of a barium hydroxide catalyst for the Horner reaction is described.The scope of the synthetic method is shown; furthermore, the yields are higher and the reaction times shorter than those previously reported for similar experimental conditions (solid-liquid).Ethyl 3-(1'-pyrenyl)-acrylate and the 3-(1'-pyrenyl)-acrylonitrile are described for the first time.
- Sinisterra, J. V.,Mouloungui, Z.,Delmas, M.,Gaset, A.
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p. 1097 - 1100
(2007/10/02)
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- KINETIC STUDY OF THE HORNER-REACTION. I
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The rates of the Horner-reaction of five phosphonates (I-V) with sodium ethoxide and various p- and m-substituted benzaldehydes, and ethanol as solvent, are reported.The kinetics of the reactions are overall third order, first order in phosphonate, ethoxide, and aldehyde, respectively.The reaction is accelerated by electron-withdrawing substituents in the benzaldehyde, giving a reaction constant, ρ, of approximately +2.0.The five-membered cyclic phosphonate (IV) is found to react about 20 times faster than its acyclic analogue (I).The rate difference is attributed to a considerable release in ring strain upon passing from the tetrahedral to the pentacoordinate state in the intermediate of the cyclic phosphonate.
- Larsen, Rolf Olaf,Aksnes, Gunnar
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p. 219 - 228
(2007/10/02)
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