Thiosemicarbazide 4-aryl derivatives

If ammonium thiocarbazate or alkyl thiocarbazates are used in place of the thiosemicarbazides, then 6//-l,3,4-thiadiazin-2(3//)-ones (279 X = O) are obtained <83EUP85227, 84USP4489074,9UHC1365, 91JHC1525,92JMC163,93GEP4134893), the 5-aryl derivatives of which are valuable cardiotonics (Section... 

Thiol compounds 252, 254 Thione compounds 252, 254 Thiosemicarbazides, N-aryl- 248 Thiourea 107, 246,254, 269, 337 -, derivatives 322, 323 Thorium cations 144 Threonine 246 Thymol 153, 197, 198 -, derivatives 288 Tigogenin 59, 195 -, acetate 63 Tigogenone 59,60 Tillmans reagent 256 Tin, cations 144,311,398 -, organic derivatives see Organotin compounds... 

Amino-substituted 1,2,3,4-thiatriazoles 87 were first prepared by a similar reaction starting from the readily available thiosemicarbazides <1895CB74>. In subsequent work this method has been widely used to prepare a variety of derivatives <1981JIC1087>. A modification of this method is to use the aza transfer reaction between aryl diazonium salts and 4-substituted thiosemicarbazide 139 (Equation 10) <19780PP59>. 

Triazolinones and triazolinethiones with alkyl or aryl substituents have been prepared by the cyclization of appropriate semicarbazide or thiosemicarbazide derivatives in 84% of 500 papers in 14% of such preparations, preformed triazoles were alkylated or arylated. 

Compounds 98 are converted relatively easily to five-membered heterocycles. 1,2,4-Triazoles 102 are obtained in high yield by reactions of 98 with hydrazine derivatives (aryl hydrazines, semicarbazide, thiosemicarbazide, benzhy-drazide, and aminoguanidine) (Scheme 7). The corresponding reaction with hydroxylamine hydrochloride affords... 

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