The reaction of imidazole (I) with phosgene (II) in hot benzene gives carbonyldiimidazole (III), which is condensed with 5-sulfamoyl-2-methoxybenzoic acid (IV) in THF yielding 1-(5-sulfamoyl-2-methoxybenzoyl)imidazole (V). Finally this compound is condensed with 1-methyl-2-aminomethylpyrrolidine (VI) in THF at room temperature
A new procedure for the synthesis of sulmepride has been reported: 5-chlorosulfonyl-2-methoxybenzoic acid (I) reacts with 2-(aminomethyl)-1-methylpyrrolidine (II) and thionyl chloride to give 5-chlorosulfonyl-N-[(1-methyl-2-pyrrolidinyl)methyl]-2-methoxybenzamide (III) which is treated with ammonia