نتایج جستجو برای: 4 michael addition
تعداد نتایج: 1922593 فیلتر نتایج به سال:
Even an \elementary" intelligence for control of the physical world will require very many kinds of knowledge and ability. Among these are ones related to perception, action, and reasoning about \near space": that region comprising one's body and the portion of space within reach of one's eeectors; chief among these are individuation and categorization of objects. These in turn are made useful ...
An efficient synthesis of chromenylphenylpropanone derivatives as warfarine-like analogues was developed by the Michael addition of 4-hydroxycoumarin to α,β-unsaturated compounds in the presence of polyvinylpolypyrrolidone supported antimony(III) chloride (PVPP-SbCl3) as a new polymeric Lewis acid catalyst in chloroform at reflux conditions without formation of 2,4-...
Tandem reactions involving Rh-catalyzed intermolecular hydroacylations of alkynes with salicylaldehydes followed by intramolecular oxo-Michael additions are described for the diastereoselective synthesis of 2,3-disubstituted chroman-4-ones. The tandem hydroacylation/oxo-Michael additions occur to form 2,3-disubstituted chroman-4-ones in high yields from a range of 1,2-disubstituted acetylenes a...
We have recently reported that retro Michael-type addition reactions can be employed for producing labile chemical linkages with tunable sensitivity to physiologically relevant reducing potentials. We reasoned that such strategies would also be useful in the design of glutathione-sensitive hydrogels for a variety of targeted delivery and tissue engineering applications. In this report, we descr...
Thiourea-modified cinchona alkaloids as bifunctional catalysts and a base could catalyze a stepwise [5+1] cyclization of divinyl ketones with nitromethane via double Michael additions, furnishing optically active 4-nitro-cyclohexanones with good yields, excellent diastereoselectivities (>20 : 1) and high enantiomeric ratios (up to 97 : 3).
Herein, we describe a short synthesis of 3-methyl-4-nitro-5-alkylethenyl isoxazoles and their reactivity as Michael acceptors. The title compounds reacted with nitromethane under phase-transfer catalysis to provide highly enantioenriched adducts (up to 93% ee) which were then converted to the corresponding γ-nitroacids.
The thioethers, S-(4-amino-2,4-dicarboxybutyl)cysteamine, S-(4-amino-2,4dicarboxybutyl)cysteine and S-(4-amino-2,4-dicarboxybuty’)glutathione, were synthesized by a Michael addition between 4-methyleneglutamic acid and the respective thiol. In dilute aqueous solution, the reactions exhibit second order kinetics; glutathione reacts much slower than cysteine or cysteamine. The adducts were charac...
Phase-transfer catalyzed asymmetric alkylation and Michael addition of 5-silylalkynyl-1,3-dioxolan-4-one were developed as a novel strategy to provide highly modular tertiary α-alkyl-α-hydroxy acids bearing an alkyne moiety.
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید