Dimethylformamide → 3-(4-(N-((dimethylamino)methylene)sulfamoyl)phenyl)-N-methoxy-5-(4-methoxyphenyl)-N,4-dimethylthiophene-2-carboxamide

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Reaction Steps

Oxalyl chloride (1.77 g, 1.2 ml, 13.9 mmol) was added drop wise at 0° C. to a solution of 5-(4-methoxyphenyl)-4-methyl-3-(4-sulfamoylphenyl)thiophene-2-carboxylic acid (compound 7e, 2.8 g, 6.94 mmol) in a mixture of dichloromethane (75 ml) and DMF (1.01 g, 1.1 ml, 13.89 mmol). The so obtained mixture was allowed to come at room temperature and stirred for 1.5 hr under a nitrogen atmosphere. The progress of the reaction was monitored by TLC. The reaction mixture was then concentrated under reduced pressure. The residue so obtained was dissolved in dry dichloromethane (75 ml) and to this was added triethylamine (2.8 g, 3.9 ml, 27.76 mmol) followed by the addition of N, O-dimethylhydroxylamine hydrochloride (1.35 g, 13.89 mmol) under stirring. The reaction mixture was then stirred at room temperature for 2 hr. The progress of the reaction was monitored by TLC. The reaction mixture was then washed with water (2×25 ml) and the organic layer so obtained was dried over anhydrous sodium sulphate and concentrated under reduced pressure to obtain crude product. The crude product was further purified by column chromatography over silica gel (100-200 mesh) using 80% ethyl acetate in hexane as an eluent to obtain the title compound (2.73 g, 78%).

Provenance & Evidence