2396-84-1Relevant articles and documents
Tandem regio- And stereoselective organocuprate-mediated bis-allylic substitutions
Dieter, R. Karl,Guo, Fenghai
, p. 2087 - 2090 (2008)
anti-5-Acetoxy-4-halo-α,β-enoates undergo sequential or tandem reactions with two different magnesium cuprate reagents to afford anti-2,3-dialkyl-4,5-enoates in high chemical yield and with excellent diastereoselectivity. The one-pot tandem procedure can be achieved with 30 mol % of CuCN and affords a rapid stereoselective combinatorial approach to vicinal disubstituted γ,λ-enoates containing functionality a either end of the carbon chain for subsequent functional group elaboration. The methodology should provide a powerful practical strategy for acyclic stereoselection.
FACILE SYNTHESIS OF (2E,4E)-DIENOIC ESTERS VIA STEREOSELECTIVE ISOMERIZATION OF 2-YNOIC ESTERS
Ma, Dawei,Lu, Xiyan
, p. 843 - 844 (1989)
(2E,4E)-Dienoic esters were synthesized stereoselectively from the corresponding 2-ynoic esters in high yield under the catalysis of an iridium hydride or ruthenium hydride complex.
Z-Selective phosphine promoted 1,4-reduction of ynoates and propynoic amides in the presence of water
Drikermann, Denis,Kupfer, Stephan,Seifert, Fabian,Steinmetzer, Johannes,Vilotijevic, Ivan,Zi, You
supporting information, p. 6092 - 6097 (2021/07/21)
Phosphine-mediated reductions of substituted propynoic esters and amides in the presence of water yield the partially reduced α,β-unsaturated esters and amides with highZ-selectivity. The competitivein situ ZtoE-isomerization of the product in some cases lowers theZtoEratios of the isolated α,β-unsaturated carbonyl products. Reaction time and the amounts of phosphine and water in the reaction mixture are the key experimental factors which control the selectivity by preventing or reducing the rates ofZ- toE-product isomerization. Close reaction monitoring enables isolation of theZ-alkenes with high selectivities. The computational results suggest that the reactions could be highlyZ-selective owing to the stereoselective formation of theE-P-hydroxyphosphorane intermediate.
Regioselective and Stereospecific Copper-Catalyzed Deoxygenation of Epoxides to Alkenes
Yu, Jingxun,Zhou, Yu,Lin, Zhenyang,Tong, Rongbiao
supporting information, p. 4734 - 4737 (2016/09/28)
Two copper salts (Cu(CF3CO2)2 and IMesCuCl) were identified as earth-abundant, inexpensive, but effective metal catalysts together with diazo malonate for chemo-/regioselective and stereospecific deoxygenation of various epoxides with tolerance of common functional groups (alkene, ketone, ester, p-methoxybenzyl, benzyl, tert-butyldimethylsilyl, and triisopropylsilyl). In particular, the unprecedented regioselectivity allowed for the first time monodeoxygenation of diepoxides to alkenyl epoxides. Density functional theory mechanistic studies showed that the deoxygenation occurred by collapsing the free ylide, unfavoring the possible intuitive pathway via cycloreversion of possible oxetane.
OMS-2 for aerobic, catalytic, one-pot alcohol oxidation-wittig reactions: Efficient access to α,β-unsaturated esters
Kona, Jagadeswara R.,King'Ondu, Cecil K.,Howell, Amy R.,Suib, Steven L.
, p. 749 - 752 (2014/03/21)
Manganese oxide octahedral molecular sieve (OMS) materials with well-defined pores have been extensively studied over two decades due to their intriguing chemical and physical properties. OMS-2, the synthetic cryptomelane form of manganese oxide, was synthesized by a modified reflux method and was found to be highly active for obtaining α,β-unsaturated esters (up to 95 % yield and with high diastereoselectivities) from a variety of benzyl, heteroaryl, allyl and alkyl alcohols via one-pot alcohol oxidation-Wittig reaction. The transformation utilizes air as the stoichiometric oxidant, and the inexpensive catalyst can be recovered and reused. Filter and use again! Porous manganese oxide molecular sieve based catalysts were found to efficiently promote the oxidation of a variety of alcohols to the aldehydes, which reacted insitu with stabilized Wittig reagent, providing almost exclusively E-α,β-unsaturated esters in good to excellent yields. The heterogeneous catalyst used was made from inexpensive starting materials, and the recovered catalyst was found to be reusable with a modest loss in activity.
Antimicrobial evaluation of 4-methylsulfanyl benzylidene/3-hydroxy benzylidene hydrazides and QSAR studies
Kumar, Davinder,Narang, Rakesh,Judge, Vikramjeet,Kumar, Devinder,Narasimhan, Balasubramanian
experimental part, p. 382 - 394 (2012/08/27)
A series of 4-methylsulfanyl benzylidene/3-hydroxy benzylidene hydrazides (1-20) was synthesized and tested for in vitro antimicrobial activity against S. aureus, B. subtilis, E. coli, C. albicans and A. niger. The results of antimicrobial studies indicated that 3-phenylacrylic acid-(3-hydroxybenzylidene) -hydrazide, 16, was the most effective as it showed both bactericidal and fungicidal properties and other compounds possessed bacteriostatic/fungistatic activity. The multi-target QSAR model demonstrated that the topological parameter, Balaban topological index (J) is effective in describing the antimicrobial activity of synthesized substituted hydrazides. Springer Science+Business Media, LLC 2010.
Synthesis, antimicrobial evaluation and QSAR studies of 3-ethoxy-4-hydroxybenzylidene/4-nitrobenzylidene hydrazides
Kumar, Davinder,Kapoor, Archana,Thangadurai, Ananda,Kumar, Pradeep,Narasimhan, Balasubramanian
experimental part, p. 1293 - 1296 (2012/01/07)
A series of 3-ethoxy-4-hydroxybenzylidene/4-nitrobenzylidene hydrazides (1-20) was synthesized and tested for in vitro antimicrobial activity. The results of antimicrobial studies indicated that the compounds having dinitro, methoxy, hydroxy and nitro substituents on phenyl ring of the aromatic acids were most active ones. The QSAR investigation indicated the importance of the topological parameter, third order molecular connectivity index ( 3χ) in describing the antimicrobial activity of synthesized hydrazides.
Phosphane-catalyzed [3+2] annulation of allenoates with aldehydes: A simple and efficient synthesis of 2-alkylidenetetrahydrofurans
Xu, Silong,Zhou, Lili,Ma, Renqin,Song, Haibin,He, Zhengjie
supporting information; experimental part, p. 8698 - 8702 (2010/03/25)
A phosphane-catalyzed [3 +2] annulation of γ-methyl allenoates with aromatic aldehydes has been reported. This annulation provides a convergent and efficient synthesis of 2-alkylidenetetrahydrofurans, which are versatile synthetic building blocks for a vast array of 5-membered oxygenated heterocycle derivatives. The EIZ isomers of 2-(ethoxycarbonylmethylene) tetrahydrofurans, was separated by column chromatography on silica gel and their structural assignments were confirmed by H and C NMR spectroscopy data and X-ray crystallographic analysis. The nature of the substituent, as well as the reaction conditions, has a significant influence on the reactivity patterns of γ-substituted allenoates with aldehydes. The phosphorus ylide, generated from the phosphonium dienolate 8 by an overall 1,4-hydrogen shift, is believed to be the key intermediate responsible for the [3 + 2] annulation and other transformations of γ-methyl allenoates with aldehydes.
Direct conversion of polyconjugated compounds into their corresponding carboxylic acids by Acetobacter aceti
Pini, Elena,Bertacche, Vittorio,Molinari, Francesco,Romano, Diego,Gandolfi, Raffaella
, p. 8638 - 8641 (2008/12/21)
The conversion of polyconjugated aldehydes or alcohols into their corresponding acids was carried out using Acetobacter aceti. The analytical results were compared with those of the acids chemically obtained using a Horner-Wittig reaction.
Quantitative structure-activity relationship studies for prediction of antimicrobial activity of synthesized 2,4-hexadienoic acid derivatives
Narasimhan, Balasubramanian,Judge, Vikramjeet,Narang, Rakesh,Ohlan, Ruchita,Ohlan, Sucheta
, p. 5836 - 5845 (2008/03/18)
A new series of 2,4-hexadienoic acid derivatives (S1-S42) has been synthesized and evaluated as antimicrobial agents against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Candida albicans, and Aspergillus niger. Quantitative structure-activity relationship (QSAR) investigation using Hansch analysis was applied to find out correlation between antimicrobial activities with physicochemical properties of the synthesized compounds. Various physicochemical descriptors and experimentally determined minimum inhibitory concentration values for different microorganisms were used as independent and dependent variables, respectively. The QSAR revealed that topological parameters especially molecular connectivity indices (χ2, 0χv, 2χv) were found to have overall significant correlation with antimicrobial activity of 2,4-hexadienoic acid derivatives. The statistical results of training set, cross-validated r2 and conventional r values gave reliability to the prediction of molecules with activity using QSAR models.
