Selective cyclization of S‐substituted pyrimidinethione: Synthesis and antimicrobial evaluation of novel polysubstituted thiazolopyrimidine and thiazolodipyrimidine derivatives

Abstract

The synthetic strategy is based on alkylation of 4-aryl-N-(4-chlorophenyl)-6-methyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxamide derivatives IV a-g, with some alkyl halides and α-haloketones, namely, methyl iodide, chloroacetonitrile, and phenacyl bromide to give the corresponding S-substituted derivatives Va-c. Treatment of IVa-c with ethyl bromoacetate in ethanol under reflux in the presence of potassium hydroxide solution led to the forma-On the other hand, compound IVa reacted with α-halo carbonitriles, namely, chloro acetonitrile, and monobromo malononitrile, to produce directly thiazolo[3,2-a]pyrimidine derivatives Xa and Xb, respectively, Compound Xb also reacted with each of formic acid, formamide, and ammonium thiocyanate to form thiazolodipyrimidine derivatives XI-XIII, respectively. Compound VIIIa-c coupled with arenediazonium salts in pyridine to give the corresponding 2-arylhydrazo derivatives XVIa-e. Compounds IV a-g and VIIIa-c were resynthesized under microwave irradiation. Some of the newly synthesized compounds were tested for their antimicrobial activities.

Diarylation of thiazolopyrimidines by laccase and their in vitro evaluation as antitumor agents

“…Thiazolopyrimidines and their derivatives possess various pharmacological properties such as anticancer 22 , antibacterial 23 , anti-inflammatory 24 . Thiazolo [3,2-a] pyrimidin-3(2H)-ones, due to the active methylene carbon at C-2, have been used as starting materials for synthesizing various organic compounds such as thioindigo-like compounds 25 , 2-benzylidene 26 , 2-arylhydrazono 27 and 2-oxyimino 28 derivatives. Up to now, application of laccases in preparation of new thiazolo [3,2-a] pyrimidin-3(2H)-one’s derivatives which include a gem-dicatechol has not been reported.…”