dihydropyrimidinones derivatives were synthesized in high yields by one pot three component Biginelli condensation from aldehyde, β keto ester and urea in ethanol,while cobalt chloride hexahydrate was used as a catalyst.This modified Biginellis reaction not only makes the reaction period short,the operation simple,but also gives high yields. dihydropyrimidinones derivatives were synthesized in high yields by one pot three component Biginelli condensation from aldehyde, β keto ester and urea in ethanol, while cobalt chloride hexahydrate was used as a catalyst. This modified Biginellis reaction not only makes the reaction period short, the operation simple, but also gives high yields.