New 2-methylisothiazolones

Article abstract of DOI:10.1002/jhet.5570370610

New N,N′-bis(alkoxycarbonyl)-L-cystine bis(methylamides) 4a, 4b and N,N′-bis(benzyloxycarbonyl)-L-cystine bis(methylamide) 4c have been synthesized by mixed anhydride method from the essential amino acid L-cystine 1 in good yield. These cystine bis(methylamides) 4a,b,c have been cyclized with sulfuryl chloride. New 2-methyl-4-amino-3-isothiazolone and 5-chloro-2-methyl-4-amino-3-isothiazolone hydrobromide salts 7, 8 have been obtained by deacylation of 2-methyl-4-(benzyloxycarbonyl)amino-3-isothiazolone 5c and 5-chloro-2-methyl-4-(benzyloxycarbonyl)amino-3-isothiazolone 6c with hydrogen bromide in acetic acid. The microbicidal effect of the new 2-methyl-3-isothiazolones 5a,b,c; 6a,b,c; 7 and 8 compounds obtained by the above method has been investigated.