Thiophene → 2-Amino-5-benzoylbenzamide

Participants

Reaction Steps

A mixture of 7.76 parts of intermediate 14, namely 5-benzoyl-2-nitrobenzamide, 2 parts of a solution of thiophene in methanol 4% and 198 parts of methanol was hydrogenated overnight at normal pressure and at 50° C. with 2 parts of palladium-on-charcoal catalyst 10%. The catalyst was filtered off and washed with tetrahydrofuran. The combined filtrates were evaporated and the residue was co-evaporated with methylbenzene. The residue was purified by column chromatography (silica gel; CHCl3 /CH3OH/CH3OH(NH3) 90:5:5). The eluent of the desired fraction was evaporated and the residue was taken up in methanol. This solution was concentrated and the product was filtered off, washed with methanol and 2,2'-oxybispropane and dried in vacuo at 60° C., yielding 2.84 parts (41.0%) of 2-amino-5-benzoylbenzamide; mp. 225.2° C. (interm. 15).

Provenance & Evidence