نتایج جستجو برای: β unsaturated compounds
تعداد نتایج: 410276 فیلتر نتایج به سال:
An environmentally benign, clean and general protocol was developed for the synthesis of aryl and heteroaryl trans-chalcones. This method involved solvent-free reaction conditions under microwave irradiation in the presence of a clay-based catalyst, and afforded the target compounds in good yields and short reaction times. Furthermore, the same conditions allowed the synthesis of symmetrical, d...
A mild and metal-free regiodivergent addition of carbon nucleophiles to α,β-unsaturated electrophiles was developed. Total 1,2-regioselectivity was observed in the addition of nitrobenzyl chloride derivative 1 to α,β-unsaturated aldehydes 2 in the presence of TDAE. Moreover, the reaction between p-nitrobenzyl chloride 1a and α,β-unsaturated iminium salts 4 led to the formation of the 1,4-adduct...
A Simple and efficient method for Michael addition of pyrrole and indole to α,β- un saturated compounds has been developed in the presence of oxalic acid under refluxing reaction condition was achieved.
In this study, we assessed the antileishmanial activity of 126 α,β-unsaturated ketones. The compounds NC901, NC884, and NC2459 showed high leishmanicidal activity for both the extracellular (50% effective concentration [EC50], 456 nM, 1,122 nM, and 20 nM, respectively) and intracellular (EC50, 1,870 nM, 937 nM, and 625 nM, respectively) forms of Leishmania major propagated in macrophages, with ...
Enantioselective organocatalysis has become a field of central importance within asymmetric chemical synthesis and appears to be efficient approach toward the construction of complex chiral molecules from simple achiral materials in one-pot transformations under mild conditions with high stereocontrol. This review addresses the most significant synthetic methods reported on chiral-amine-catalyz...
Electrophilic Epoxidation of α,β-Unsaturated Oximes with Dioxiranes and Ring Opening of the Epoxides
α,β-Unsaturated oximes underwent electrophilic epoxidation with in-situ-generated dimethyldioxirane to give the corresponding epoxides in good yields. This reaction is an example of “carbonyl umpolung” by transformation α,β-unsaturated ketones their oximes. Nucleophilic ring-opening reactions afforded α-substituted products. Shi asymmetric proceeded moderate enantioselectivity.
Naturally occurring polyhydroxylated amines such as (+)-1-deoxynojirimycin, polyoxamic acid, anisomycin, (-)swainsonine, and alexine stereoisomers, which have interesting biological activities including glucosidase- and mannosidase-inhibitory activity, immunoregulatory activity, and antibacterial effects, were synthesized stereoselectively starting from (S)-pyroglutamic acid derivatives. α,β-Un...
The synthesis of new α,β-unsaturated furanuronic acid derivatives of α-gluco-, β-gluco- and β-manno-chloraloses via a convenient one pot procedure using the Knoevenagel-Doebner reaction approach are described. The dialdofuranose derivatives were reacted with malonic acid under Knoevenagel-Doebner reaction conditions and (E)-α,β-unsaturated furanuronic acid derivatives were obtained.
β'-Chloro and β',γ'-unsaturated trichlorotitanium enolates, which were formed in situ by titanium(IV) chloride-mediated ring cleavage of 3,3-dialkylcyclobutanones and 3-[(trimethylsilyl)methyl]cyclobutanones, reacted with enones to give Michael adducts with keeping a labile β'-chloro or β',γ'-unsaturated group.
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