Triethylamine → 5-bromo-N-[4-methoxy-3-(4-methyl-1-piperazinyl)phenyl]thiophene-2-carboxamide

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Reaction Steps

5-Bromo-2-thiophenecarboxylic acid (0.375;1.8 mmol) was heated at reflux in thionyl chloride (8 ml) for 30 minutes, cooled, evaporated in vacuo and the residue azeotroped with toluene. The residue was redissolved in CH2Cl2 (10 ml) and treated with dry triethylamine (0.25 ml;1.81 mmol) and 4-methoxy-3-(4-methyl-1-piperazinyl)benzenamine (0.4 g;1.81 mmol). The solution was stirred under Ar (18 hours), evaporated in vacuo and partitioned satd. K2CO3 (aq)/EtOAc. The organic phases were combined, dried over Na2SO4, filtered and the filtrate evaporated in vacuo to a brown gum. The gum was purified by flash silica-gel chromatography and eluted with 3%MeOH/CHCl3 to yield the title compound as a brown gum which crystallised on standing (0.388 g;52%), and was converted to the oxalate salt, mp=114°-115° C.

Provenance & Evidence