Reaction of 3-Amino-2H-azirines with Diphenylcyclopropenethione : 3-Dimethylamino-2H-azirines (4a, 4b) react with diphenylcyclopropenethione (8) to give 4(3H)-pyridinethione derivatives of type 10 (Scheme 3). The reaction mechanism for the formation of 10 is given in Scheme 3 by analogy with a previous reported one  . Hydrolysis of the 4(3H)-pyridinethione 10a yields 2-oxo-2,3-dihydro-4(1H)-pyridinethione (11) and reduction of 10a with sodium borohydride leads to the 2,3-dihydro-4(1H)-pyridinethione 12 (Scheme 4). The results of the reaction of 4a, 4b and the thione 8 demonstrate ihe similarity to the reaction of 4a, 4b and 2  (cf. Scheme 1). In contrast, the reactions of imines of type 7a with 2 and 8, respectively, lead to different products (cf. ).