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

Participants

Reaction Steps

A suspension of 6-fluoropyrido[3,4-d]pyrimidine-4(3H)-one (U.S. patent application Ser. No. 08/358,352, 1994) (1.65 g) in 50 mL thionyl chloride and several drops of dimethyl formamide was heated under reflux until a clear solution was obtained (20 minutes), and then for a further 30 minutes. The volatiles were removed under reduced pressure, and the residue was dissolved in dichloromethane and washed with aqueous Na2CO3. The solvent was dried and removed to give crude 4-chloro-6-fluoropyrido[3,4-d]pyrimidine which was dissolved in 2-propanol (50 mL) containing 3-bromoaniline (2.1 g). The mixture was heated under reflux for 15 minutes to give a precipitate, which was redissolved by the addition of triethylamine. After the addition of water, the solution was concentrated and cooled to give 4-[(3-bromophenyl)amino]-6-fluoropyrido[3,4-d]-pyrimidine, (2.29 g), mp (MeOH) 219.5-221° C.

Provenance & Evidence