Water → 6-bromo-3-(4-methoxy-phenyl)-2H-pyrrolo[1,2-a]pyrazin-1-one

Participants

Reaction Conditions

Reaction Steps

A mixture of 5-bromo-1-[2-(4-methoxy-phenyl)-2-oxo-ethyl]-1H-pyrrole-2-carboxylic acid methyl ester (0.15 g, 0.43 mmol) and ammonium acetate (170 mg, 2.21 mmol) in glacial acetic acid (2 mL) was heated at 130° C. overnight. The reaction was stopped, and the recovered starting material was suspended in 1,4-dioxane (2 mL), treated with ammonium acetate (170 mg, 2.21 mmol) and then was heated in a sealed tube at 120° C. for 5 h. At this time, the reaction was treated with additional ammonium acetate, and the mixture continued stirring at 120° C. overnight. At this time, the reaction was treated with water. The resulting precipitate was collected by filtration, washed with water (2×) and dried in vacuo to afford 6-bromo-3-(4-methoxy-phenyl)-2H-pyrrolo[1,2-a]pyrazin-1-one (78 mg, 55%) as red solid. 1H NMR (DMSO-d6) δ ppm 7.54-7.63 (m, 4H), 7.03 (d, J=9.0 Hz, 2H), 6.96 (d, J=1.3 Hz, 1H), 3.80 (s, 3H). LC-MS calcd. for C14H12BrN2O2 [(M+H)+] 319, obsd. 319.0.

Provenance & Evidence