3-Acetyl-5,6-dimethoxy-2(3H)-benzothiazolone → 5,6-dimethoxybenzo[d]thiazol-2(3H)-one

Participants

Reaction Steps

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.

Provenance & Evidence