Diisopropylethylamine → 3-methyl-6-[2-(tetrahydropyran-2-yloxy) ethyl]-5,6,7,8-tetrahydro-1H-pyrido[4,3-d]pyrimidine-2,4-dione

Participants

Reaction Conditions

Reaction Steps

40 g of ethyldiisopropylamine and 52.5 g of 2-(2-chloroethoxy)tetrahydropyran (96% pure according to GC) were added to 54.5 g of 3-methyl-5,6,7,8-tetrahydro-1H-pyrido[4,3-d]pyrimidine-2,4-dione in 1.5 l of dimethylformamide, with stirring, and the mixture was heated for 30 h at 70° C. It was concentrated under vacuum, the residue was worked up by extraction with dichloromethane and water and the combined dichloromethane phases were dried and concentrated to give 25 g of 3-methyl-6-[2-(tetrahydropyran-2-yloxy) ethyl]-5,6,7,8-tetrahydro-1H-pyrido[4,3-d]pyrimidine-2,4-dione, which was purified by bulb-tube distillation at a bath temperature of 80° C. and 0.1 mbar and by column chromatography on aluminum oxide (activity grade III) and elution with dichloromethane/ethanol (volume ratio 95:5).

Provenance & Evidence