N,N-Diethylaniline → Methyl 8-fluoro-2H-1-benzopyran-5-carboxylate

Participants

Reaction Conditions

Reaction Steps

Methyl 4-fluoro-3-propargyloxybenzoate (14.0 g, 67.2 mmol) was mixed with N,N-diethylaniline and the reaction was heated to 220° C. for 5 hours. The black reaction mixture was allowed to cool, dissolved in diethyl ether (600 mL) and washed with 2 M HCl in portions (1 L). The aqueous washings were re-extracted with diethyl ether, the combined ether phases were washed with H2O until neutral, treated with brine, dried with MgSO4, filtered, and the solvent was removed in vacuo to give a dark brown crude residue. The crude solid was chromatographed on silica (eluent: methylene chloride/carbon tetrachloride 1:1) to give 11.9 g (85% yield) of a tannish yellow solid as the title compound (mp 73.5-74.5° C.). EIMS (70 eV) m/z (relative intensity) 208 (65, M+), 207 (42), 194 (12), 193 (100), 177 (32), 149 (10), 148 (12).

Provenance & Evidence