Phosphorus oxychloride → 4-Chloro-6-fluoropyrido[3,2-D]pyrimidine

Participants

Reaction Steps

A suspension of 6-fluoro-3H-pyrido[3,2-d]pyrimid-4-one (0.20 g, 1.21 mmol) in POCl3 (30 mL) is heated under reflux with stirring until homogeneous (2 h), and then for a further 1 h. Excess POCl3 is removed under reduced pressure, and the residue is partitioned between CH2Cl2 and saturated aqueous NaHCO3. Workup of the organic portion gives crude 4-chloro-6-fluoropyrido[3,2-d]pyrimidine (100%) as an unstable white solid which is used directly in the next step.

Provenance & Evidence