New Amides of 5-Acylamino-3-Methyl-4-Isothiazolecarboxylic Acid and their Immunotropic Activity

Several new amides 4 of 5‐substituted 3‐methyl‐4‐isothiazolecarboxylic acid were obtained. These compounds have acetylamino or benzoylamino groups in position 5 of the isothiazole ring. In position 4, the carboxylic group was transformed in the amides using amino‐acid esters. Activities of the obtained derivatives were checked in the humoral immune response and delayed type hypersensitivity reaction to sheep red blood cells (SRBCs) in vivo.