The reaction of t-butyl hypochlorite with different thiocarbonyl compounds has been studied. Primary thioamides 1a-c give 1, 2, 4-thiadiazole derivatives. N-Phenylthiourea 4a gives 5- imino-4-phenyl-3-phenylamino-4, 5-dihydro-1, 2, 4-thiadiazoline 15. Secondary and tertiary thioamides 2a-d, N-methyl-2-thiopyrrolidinone 3, N, N'-dicyclohexylthiourea 4b, N, N, N'-tri- methylthiourea 4c, 5-ethyl-5-phenylthiobarbituric acid 5, xanthione 7a, Michler's ketone ...