نتایج جستجو برای: tetrasubstituted imidazoles
تعداد نتایج: 4152 فیلتر نتایج به سال:
Studies with C-2-labelled glycine and alanine in model systems containing 2,3-butanedione, glyceraldehyde or glyoxal have indicated that imidazoles and oxazoles can be formed from a-dicarbonyl compounds through Strecker reaction and subsequent formation of a-amino carbonyl reactive intermediates. These intermediates can react with any aldehyde in the reaction mixture to form an imine which in t...
The configurational and conformational behavior of some new 3,3,9,9-tetrasubstituted-2,4,8,10-tetraoxaspiro[5.5]undecane derivatives with axial chirality was investigated by conformational analysis and variable temperature NMR experiments.
An imidazole moiety is often found as an integral part of fluorophores in a variety of fluorescent proteins and many such proteins display pH-dependent light emission. In contrast, synthetic fluorescent compounds with incorporated imidazoles are rare and have not been studied as pH probes. In this report, the richness of imidazole optical properties, including pH sensitivity, was demonstrated b...
Anthelmintic resistance creates a major hitch over the decades throughout the world. As per WHO only few drugs are frequently used in the treatment of helminth infestations in human beings. In view of this, an attempt has been made to study the anthelmintic activity of some newly synthesized 1-substituted imidazoles (1a-1d, 2a-2d) were synthesized and characterized by their spectral data. All t...
The kinetics of the reactions of some imidazoles, benzimidazoles and benzotriazoles with benzhydrylium ions (diarylcarbenium ions) have been studied photometrically in DMSO, acetonitrile, and aqueous solution at 20 degrees C. The resulting second-order rate constants have been used to determine the nucleophile-specific parameters N and s of these azoles according to the linear-free-energy relat...
Two simple protocols for the synthesis of 1, 2, 4, 5- tetrasubstitutedimidazoles using nano-SPA as a reusable, eco- friendly, inexpensive, and efficient catalyst are reported. Short reaction times, high yields, scale-up and easy workup are the advantages of these protocols.
A new class of 4H-imidazoles was synthesized starting from fused-ring aromatic dinitriles. Strong bathochromic shifts of the longest wavelength absorptions were observed in the corresponding UV/vis spectra due to a conversion of the merocyanine chromophores into cyanines/(aza)oxonoles upon protonation/deprotonation of the 4H-imidazoles. Novel boratetraazapentalenes were synthesized via a cycliz...
Room temperature zinc-mediated diastereoselective allylation or propargylation of isatin-derived N-tert-butanesulfinyl ketimines for synthesis of highly enantiomerically enriched tetrasubstituted 3-aminooxindoles is described.
An alternative strategy for the synthesis of 1-aryl- and 1-alkyl-2-methylsulfanyl-4-(4-fluorophenyl)-5-(pyridin-4-yl)imidazoles as potential p38α mitogen-activated protein kinase inhibitors is reported. The regioselective N-substitution of the imidazole ring was achieved by treatment of α-aminoketones with different aryl or alkyl isothiocyanates. In contrast to previously published synthesis ro...
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