Sodium Carbonate → Ethyl 7-chloropyrazolo[1,5-a]pyrimidine-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a stirred suspension ethyl 7-hydroxypyrazolo[1,5-a]pyrimidine-3-carboxylate (0.95 g, 4.6 mmol) in POCl3 (8.0 mL, 86 mmol) was added dimethyl aniline (0.8 μL, 0.006 mmol) and the mixture was heated at 80° C. for 2 hours. The mixture was slowly poured onto ice, and the pH was carefully adjusted to ˜7 with 1N NaOH, then to pH 10 with solid Na2CO3. The mixture was then extracted with dichloromethane (3×). The organics were combined, washed with brine, dried (MgSO4) and evaporated to dryness. Trituration of the solids with hexanes gave ethyl 7-chloropyrazolo[1,5-a]pyrimidine-3-carboxylate (260 mg, 25%) as a tan solid. ESI-MS m/z calc. 225.0, found 226.5 (M+1)+; Retention time: 0.87 minutes (3 min run).

Provenance & Evidence