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

Participants

Reaction Steps

27 g of ethyldiisopropylamine, 18 g of lithium bromide and 46 g of 2-(4-chlorobutoxy) tetrahydropyran (86.3% pure according to GC) were added to 36.3 g of 3-methyl-5,6,7,8-tetrahydro-1H-pyrido[4,3-d]pyrimidine-2,4-dione in 1 l of dimethylformamide, with stirring, and the mixture was stirred for 5 h at 70° C. It was concentrated under reduced pressure and 34.5 g of crude 3-methyl-6-[4-(tetrahydropyran-2-yloxy)butyl]-5,6,7,8-tetrahydro-1H-pyrido[4,3-d]pyrimidine-2,4-dione were obtained after working-up of the residue by extraction with dichloromethane and water and after drying and concentration of the combined dichloromethane phases, and this crude product was purified by column chromatography on aluminum oxide (actiVity grade III) and elution with dichloromethane/ethanol (volume ratio 90:10).

Provenance & Evidence