METHOD FOR PRODUCING SULFONAMIDE

摘要

PROBLEM TO BE SOLVED: To provide an economical and efficient method for producing a specific N-carbamate type protected benzenesulfonamide derivative which is suitable for industrial production, the specific benzenesulfonamide derivative and its salt derived from the aforesaid derivative and a method for producing a crystal of the benzenesulfonamide derivative salt. SOLUTION: An N-carbamate type protectedβ-aminoalcohol or an N- carbamate type protectedβ-aminoepoxide is reacted with N-isobutyl-3- nitrobenzenesulfonamide in the presence of a base to obtain the N-carbamate type protected benzenesulfonamide derivative. In the benzenesulfonamide derivative in which a protecting group of the amino group is benzyloxycarbonyl group, the protecting group is removed by reacting methanesulfonic acid. An impurity is efficiently separated and removed into the mother liquor by crystallizing a methanesulfonate of the benzenesulfonamide derivative containing at least a diastereomer thereof as the impurity from an alcohol or an alcoholic mixed solvent.