Addition reactions of diketene. IV. Reaction of diketene with thioureas, thioamide, and aminothiol.

Abstract

The reaction of benzimidazoline-2-thione (2) with diketene (1) gave the oxazine derivative 3 and the thiazine derivative 4. However, the reaction of 2-indolinethione (6) with diketene afforded only the thiazine derivative 7. On the other hand, no cyclized compound was obtained from 2-indolinone (8) and diketene. The reactions of N, N'-diphenylthiourea (11) and 2-aminobenzothiol (14) with diketene were also studied ; 11 and 14 gave the thiouracil 12 and the benzothiazine 16, respectively.