α Thioureidoalkylation of urea heteroanalogs such as thiosemicarbazide, amino guanidine, sulfamide, and sulfonamides with 4,5 dihydroxyimidazolidine 2 thiones has been studied. Previously unknown 4,5 bis[thiosemicarbazido(guanidinoamino)]imidazolidine 2 thiones, 5,7 dialkylperhydroimidazo[4,5 e] [1,2,4]triazine 3,6 dithiones, 4,6 diethyl 5(3H) thioxotetrahydro 1H imidazo[4,5 c][1,2,5]thiadiazole 2,2 dioxide, and 1,3 dialkyl 4 [guanidinoimino(arylsulfonylimino)]imidazolidine 2 thiones have been synthesized. Key words: α thioureidoalkylation, thiosemicarbazide, aminoguanidine, sulfamide, 4,5 dihydroxyimidazolidine 2 thiones, 4,5 bis[thiosemicarbazido(guanidinoamino)]imidazol idine 2 thiones, 5,7 dialkylperhydroimidazo[4,5 e][1,2,4]triazine 3,6 dithiones, 4,6 diethyl 5(3H) thioxotetrahydro 1H imidazo[4,5 c][1,2,5]thiadiazole 2,2 dioxide, 1,3 dialkyl 4 [guanidinoimino(arylsulfonylimino)]imidazolidine 2 thiones.α Ureidoalkylation of ureas and their analogs with 4,5 dihydroxyimidazolidin 2 ones have been carefully studied in our laboratories. 1-5 α Ureidoalkylation of thiosemicarbazide, aminoguanidine, and sulfamides yielded 5,7 dialkyl 3 thioxoperhydroimidazo[4,5 e][1,2,4]tri azin 6 ones (1), 2 4,5 bis(thiosemicarbazido) and 4,5 bis (guanidinoamino)imidazolidin 2 ones (2, 3), 2 4 (guani dinoamino) and 4 (sulfonylimino)imidazolidin 2 ones (4-6), 2-4 and 5(3H) thioxotetrahydro 1H imidazo[4,5 c] [1,2,5]thiadiazole 2,2 dioxides (7). 5 Only few examples of the synthesis of glycoluril heteroanalogs by condensation of ureas with 4,5 dihydroxy imidazolidine 2 thiones (DHIT) have been published. 6,7The present work is devoted to α thioureidoalkylation of urea heteroanalogs (thiosemicarbazide, aminoguani dine, sulfamide, and sulfonamides) with DHIT 8a-c and development of the synthetic methods towards novel imidazolidine 2 thione derivatives.Thioureidoalkylation of thiosemicarbazide with DHIT 8a-c under conditions described previously 2 for the syn thesis of compounds 2 (water, pH 2, 80 °C, DHIT : thio semicarbazide = 1 : 2) resulted in 4,5 bis(thiosemi carbazido)imidazolidine 2 thiones 9a-c in 70-75% yields and perhydroimidazo[4,5 e][1,2,4]triazine 3,6 di thiones 10a-c (Scheme 1). Imidazotriazines 10b,c were isolated in 5-15% yields. Together with signals of the main product 9a, the signals that were attributed to com X = S (2), NH 2 + Cl -(3)pound 10a (4.94 and 5.25 (both d, each 1 H, CH-CH, J = 8.5 Hz); 5.69 (br.s, 1 H, NH); 7.29 (br.s, 2 H, 2 NH);