Microwave assisted Biginelli cyclocon densation for the synthesis of dihydropyrimidinones catalysed by H2SO4Clay NPs and their applications

Abstract The Acid Modification of Bentonite clay (AMC) process was firstly reported and has been developed in one pot by ionic exchange of inorganic interlayer clay combined with different concentrations of acid (H2SO4) under Microwave irradiation. The maximum basal spacing of 28 A was found in 2M AMC clay confirmed PXRD analysis. EDAX micrographs of raw and AMCs showed the percentage of elemental analysis (H%=38.21 for 2M). Further, it was successfully applied in the Biginelli reaction of Dihydropyrimidinones (DHPMs) synthesis by cyclocondensation reaction under microwave irradiation and structurally confirmed by spectral techniques such as HNMR, C13NMR, FT-IR, Mass and UV-Visible absorption spectra. The yields of DHPMs are 88%, 90%, 92% and 92.6 % for EMDHPM, EMNDHPM, EMMDHPM and EMHMDHPM respectively. The antimicrobial activity of synthesized dihydropyrimidinones was examined using Gram-positive (Staphylococcus aureus) and Gram-negative (E. coli) bacterial species showed efficiently inhibited the bacterial growth activities at 4 mg/mL concentration. The results confirmed that the newly prepared DHPMs compounds act as efficient antimicrobial agent and synthesized AMC material as potential catalyst.