Hydrogen Bromide → 5-(4-Aminophenyl)-2(1H)-pyrazinone hydrobromide

Participants

Reaction Steps

A solution of 5-(4-benzyloxycarbonylaminophenyl)-2(1H)-pyrazinone (1.1 g) in 15% w/v hydrogen bromide in acetic acid solution (30 ml) was refluxed for 30 min. The yellow precipitate which formed was filtered off and it was washed with a little 1-propanol and then recrystallised from ethanol-water containing 2 drops of concentrated hydrobromic acid to give 5-(4-aminophenyl)-2(1H)-pyrazinone hydrobromide (1.03 g m.p.>300° C.). This is converted to 5-(4-aminophenyl)-2(1H)-pyrazinone by neutralising.

Provenance & Evidence