反应详情

2.533 gm (0.01 mol) of 3-acetyl-5,6-dimethoxy-2(3H)-benzothiazolone were refluxed for 2 hours in a mixture of 40 ml of ethanol and 50 ml of concentrated ammonia. The mixture was concentrated to one-fourth of its original volume, allowed to cool and filtered. The dried residue was purified by chromatography on silica gel, using 1,2-dichloroethane/acetone (volume ratio 9:1) for elution. The residues of the evaporated eluates were recrystallized from methanol in the presence of activated charcoal, yielding 1.78 gm (84% of theory) of the desired product having a melting point of 192°-193° C.

1. concentrationThe mixture was concentrated to one-fourth of its original volume
2. temperatureto cool
3. filtrationfiltered
4. customThe dried residue was purified by chromatography on silica gel
5. washfor elution
6. customThe residues of the evaporated eluates were recrystallized from methanol in the presence of activated charcoal