CYCLOADDITION ELIMINATION-REACTIONS OF PHENYLISOCYANATE WITH OXO AND THIONO DERIVATIVES OF ALIPHATIC SUBSTITUTED 5-IMINO-1,2,4-DITHIAZOLIDINES AND 3-THIONO-1,2,4-THIADIAZOLIDINES (MUSTARD OIL OXIDES AND SULFIDES)

5-Imino-1,2,4-dithiazolidin-3-ones 1 and -3-thiones 3 react with phenylisocyanate to afford 5-imino-1,2,4-thiadiazolidin-3-ones 6. In comparison isomeric 3-thiono-1,2,4-thiadiazolidin-5-ones 2, 5, and -5-thiones 4 yield 3-imino-1,2,4-thiadiazolidin-5-ones 8, 10, and -5-thiones 7. Thermolyses of thiadiazolidines 5 and 10 afford further 1,2,4-thiadiazolidines 9, 11. Compounds 8 - 11 are available also by reaction of substituted guanidines with chlorocarbonyl sulfenylchloride.