Comparative study of chemical synthesis of dihydropyrimidine (DHPMS) derivatives by Biginelli Reaction using microwave irradiation and conventional method

The majority of the drugs on the market today are entirely chemically synthesized in the laboratory. Several scientists had synthesized dihydropyrimidine (DHPMs) derivatives showing a wide spectrum of biological actions as antibacterials, antivirals as well as antitumor agents. This activity is principally due to presence of steriogenic carbon C4 in their structure. The current investigation is comparative study of chemically synthesis of two DHPMs derivatives by Biginelli Reaction using microwave irradiation and conventional method. The synthesis of DHPMs derivative involves a multicomponent reaction (aldehyde derivative, urea /thiourea and 1,3-dicarbonyl compounds) in presence of HCl / NH4Cl as a catalyst. Two derivative viz. 3,4-dihydropyrimidin-2-(1H)-ones and 3,4-dihydropyrimidin-2-(1H)-thiones were synthesized and characterized using IR. The melting points were obtained are 203 °C and 211 °C respectively. Microwave irradiation was easy and gave more yield than conventional method. This study will help to develop easy protocol for the synthesis of many more DHPMs derivative with high yield.