Sodium Carbonate → 5-(4-Cyano-2-fluoro-phenyl)-isoxazole-3-carboxylic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

A mixture of 5-chloro-isoxazole-3-carboxylic acid ethyl ester (600 mg), 4-cyano-2-fluorophenylboronic acid (665 mg), and aqueous Na2CO3 solution (2 M; 4.41 mL) in 1,4-dioxane (15 mL) is purged with argon for 15 min prior to the addition of Pd(PPh3)4 (276 mg). The reaction mixture is heated under an argon atmosphere to 140° C. for 20 min in a microwave oven. The solvent is evaporated in vacuo and the residue is mixed with water and ethyl acetate. The aqueous phase is extracted with ethyl acetate and the combined extracts are washed with brine, dried over MgSO4 and concentrated in vacuo. The crude product is purified by silica gel chromatography (cyclohexane/ethyl acetate 80:20→50:50). LC (method 3): tR=1.50 min; Mass spectrum (ESI+): m/z=261 [M+H]+.

Provenance & Evidence