Water → 3-(4-tert-butyl-phenyl)-7-fluoro-2H-pyrrolo[1,2-a]pyrazin-1-one

Participants

Reaction Steps

A solution of 52.4 mg (0.165 mmol) 1-[2-(4-tert-butyl-phenyl)-2-oxo-ethyl]-4-fluoro-1H-pyrrole-2-carboxylic acid methyl ester and 382 mg (4.95 mmol) ammonium acetate in 0.5 ml acetic acid is stirred for 18 hours at 110° C. The reaction mixture is allowed to cool to room temperature and excess water is added. The resulting precipitate is filtered off, washed with water and dried. It is chromatographed on a silica gel column with cyclohexane/ethyl acetate as eluent to give 3-(4-tert-butyl-phenyl)-7-fluoro-2H-pyrrolo[1,2-a]pyrazin-1-one as light brown crystals; HPLC/MS 2.88 min (B), [M+H] 285; 1H NMR (400 MHz, DMSO-d6) δ [ppm] 10.97 (s, 1H), 7.61 (s, 1H), 7.58 (d, J=8.5, 2H), 7.48 (m, 3H), 6.75 (d, J=1.6, 1H), 1.31 (s, 9H).

Provenance & Evidence