Condensation of 5-Acetyl-3,4-dihydropyrimidin-2(1H)-ones with Hydrazine

Resumo

3,4-Dihydropyrimidines obtained by the Biginelli reaction react with hydrazine to give a mixture of N-[(3,5-dimethyl-1H-pyrazol-4-yl)(R)methyl]ureas and 4-R-3,7a-dimethyl-1,3a,4,5,7,7a-hexahydro-6H-pyrazolo[3,4-d]pyrimidin-6-ones. The latter transform into N-[(3,5-dimethyl-1H-pyrazol-4-yl)(R)methyl]ureas in an acidic medium.