GB589730A - Improvements in or relating to the preparation of benzenesulphonyl thiourea derivatives - Google Patents

Abstract

A metal sulphydrate is reacted with an N-benzenesulphonylisothiourea substituted on the sulphur atom by an alkyl or aralkyl group, and the product treated with an acid to form benzenesulphonylthiourea. In examples: (1) N - p - amino - benzenesulphonyl - S - methyl - iso - thiourea is mixed with an alcoholic solution of sodium sulphydrate and the product dissolved in water and hydrolysed with acetic acid to form p-aminobenzenesulphonyl thiourea; (2) N - p - acetylaminobenzenesulphonylthiourea is prepared similarly from N - p - acetylamino - benzenesulphonyl - S - methyl - isothiourea using hydrochloric acid instead of acetic acid in the hydrolysis; (3) N-benzenesulphonylthiourea is prepared from N-benzene-sulphonyl-S-methylisothiourea by the method of the first example; and (4) N-p-acetylaminobenzene-sulphonyl-S-benzyl-isothiourea is heated with sodium sulphydrate, the benzyl mercaptan removed by extraction with benzene, the residue hydrolysed with hydrochloric acid, and the N - p - acetylaminobenzenesulphonylthiourea obtained is de-acetylated. N - p - Aminobenzenesulphonyl - S - methyl - iso - thiourea is obtained by de-acetylation of N-p-acetylaminobenzenesulphonyl - S - methyl - iso - thiourea prepared by condensing p-acetylaminobenzenesulphonyl chloride with a salt of S-methyl-isothiourea in presence of alkali in dilute acetone. N - p - Acetylaminobenzenesulphonyl - S - methyl - isothiourea is made by condensing p-acetylaminobenzenesulphonyl chloride with the hydrochloride of S-benzylisothiourea in presence of caustic soda in aqueous acetone.