An efficient and green synthesis of dihydrothiazolo [3,2-a] purine-2 (1H)-one derivatives using bleaching earth clay (BEC) as a recyclable catalyst and study of antibacterial potency

The present work described the one-pot multicomponent green and novel protocol for the synthesis of dihydrothiazolo [3,2-a] purine-2(1H)-one derivatives from novel purines and substituted 2-amino-thiazoles using BEC (pH 12.5, 10% by weight) as a recyclable heterogeneous catalyst in environmentally sustainable reaction medium PEG-400. The antibacterial potency was studied using a disc diffusion assay against two bacterial strains such as Staphylococci aureus (MTCC 1430) and Escherichia coli (MTCC 1573). The results of biological tests of newly synthesized derivatives 4a, 4b, 4d, 4g, and 4h display marked antibacterial potency against tested pathogens. The biological relevance of these synthesized derivatives is due to the presence of thiazole nucleus in combination with a purine ring. Further, structure conformation of synthesized titled compounds was presented with different spectroscopic methods such as ¹H-NMR, ¹³C-NMR, IR, and GCMS. Numerous benefits of the current method include the catalyst's recyclability, clean reaction conditions, a quick reaction rate, increased product yield, and the lack of dangerous reagents.