Dimethylformamide → 4-CHLORO-6-FLUOROPYRIDO[3,4-D]PYRIMIDINE

Participants

Reaction Steps

A stirred suspension of 30.0 g (182 mmol) of 6-fluoropyrido[3,4-d]pyrimidin-4(3H)-one in 182 mL of 1,2-dichloroethane was treated successively with 182 mL of thionyl chloride, then ca. 1 mL of N,N-dimethyl-formamide. The mixture was heated at reflux for 2.5 hours, then concentrated to a solid that was coevaporated twice with 1,2-dichloroethane. The residual dark brown solids were dissolved in dichloromethane, and the solution was filtered through a short pad of silica gel eluting with dichloromethane. Concentration of product fractions afforded 30.5 g (91%) of pure product after drying. Crystallization of a small sample from tert-butyl methyl ether gave product of mp 75-76° C. 1H NMR (CDCl3): δ9.29 (s, 1H, 9.16 (s, 1H), and 7.65 (dd, J=0.7 Hz, 2.0 Hz, 1H).

Provenance & Evidence