反应详情

6.5 g of 3-benzy1-5,6,7,8-tetrahydro-1H-pyrido[4,3-d]-pyrimidine-2,4-dione hydrochloride were added at 0° C. to a mixture of 5.5 ml of 90% formic acid and 4 ml of 37% formaldehyde, with stirring. After heating for 8 h at the reflux temperature, 26.5 ml of i N hydrochloric acid were added at room temperature and the mixture was then concentrated under reduced pressure. After recrystallization from isopropanol/water, 3-benzyl-6-methyl-5,6,7,8-tetrahydro-1H-pyrido[4,3-d]pyrimidine-2,4-dione hydrochloride was obtained from the residue.

1. additionwere added at room temperature
2. concentrationthe mixture was then concentrated under reduced pressure
3. customAfter recrystallization from isopropanol/water