A rapid and efficient protocol for the synthesis of novel nitrothiazolo[3,2-c]pyrimidines via microwave-mediated Mannich cyclisation

A rapid access to novel and diverse 3-oxothiazolo[3,2- $$c$$ c ]pyrimidine-8-carboxylates using multicomponent Mannich cyclisation reactions

“…Also, the use of triethylamine or potassium carbonate in acetonitrile did not increase product yields (63-65%) (entry 8-9, Table 1). As opposed to the results in our previous work [2], the use of water as a solvent did not provide any increase in product yields (40-48%) in the current study (entry 5-6, Table 1). Although we also applied microwave irradiation (in dynamic mode, 80-90 • C) at different reaction times (2-10 min), no product 4 was detected by TLC analysis of the crude reaction mixture, only some decomposition reactions were obtained in most of the trials (entry 7 and 11, Table 1).…”

“…Product 4j was purified by flash column chromatography and the structure assigned on the basis of proton NMR chemical shifts of two methylenic groups in the tetrahydropyrimidine recorded at 3.63 and 4.51 ppm, consistent with the NMR data and X-ray structures of their analogs described in our previous work [2].…”

“…They are formed by different combinations of thiazole and pyrimidine rings [2]. Especially, thiazolo [4,5-d]pyrimidines are the thiaanalogs of purine bases (adenine, guanine) and so they have received great attention by the pharmaceutical industry and researchers working on the development of new therapeutics in the field of medicinal chemistry for many years.…”

“…We recently reported a rapid synthesis of novel 6-substituted nitrothiazolo[3,2-c]pyrimidines bearing variety of aryl or alkyl groups through Mannich cyclisations of nitroenamine and different amines in the presence of formaldehyde under microwave conditions (Scheme 1)[2].Some examples with enamine compounds or intermediates are known for the generation of various heterocycles…”

Cytotoxic Effects of Thiazolo[3,2-C]Pyrimidines Against Mcf-7 And Hepg2/C3a Carcinoma Cell Lines

“…Reactions were monitored with precoated TLC plates (Merck 5735) and column chromatography were performed for purifications of title compounds by using silica gel 60 (Merck 109385). Starting materials, 2-(nitromethylene)thiazolidine (1a) and (Z)-ethyl 2-(5-methyl-4-oxothiazolidin-2-ylidene) acetate (1b), were prepared and characterized according to reported methods [14,24].…”