Studies of Heterocyclic Compounds. V. Synthesis of 5, 6-Dihydrothiazolo-[2, 3-b] thiazolium Salts and Their Reactions with Amines. A New Synthesis of 2-Aminothiazoles

Abstract

5, 6-Dihydrothiazolo [2, 3-b] thiazolium salts (1a-d) were synthesized from 2-mercapto-thiazoline and α-haloketones. The reaction of 1 with a secondary amine gave 2-aminothiazole (7a-1) with the liberation of thiirane (9) via an unstable adduct, 7a-amino-2, 3, 5, 6-tetrahydrothiazolo [2, 3-b] thiazole (8a-g). The reaction of 1 with a primary amine afforded 3-(2-mercaptoethyl)-4-thiazolin-2-imine (10) and/or its disulfide (11). The reaction of 1 with an amine was concluded to be initiated by the attack of the reagent on C-7a.