Conversion of Substituted Thiosemicarbazide and 1,3,4- Oxadiazole to 5- Substituted / 4,5- Di substituted -1,2,4- Triazole-3-thiol

In this paper substituted 1,2,4-triazoles were synthesized from ethylglycinate, the synthesis route pass through substituted thiosemicarbazidesor 1,3,4-oxadiazoles. Ethyl glycinate prepared from glycine, which wastreated with HCl gas in absolute ethanol to give ethyl glycinatehydrochloride, which then treated with dry ammonia in methylene chloride to give the free glycine ester. Treatment of ethyl glycinate with substituted benzaldehyde gave the corresponding Schiff base, which were converted to hydrazide by their reaction with hydrazine hydrate in ethanol. The hydrazides were treated with carbon disulfide in ethanolic potassium hydroxide to give substituted 1,3,4-oxadiazole. Treatment of the oxadiazoles with primary amines or hydrazine hydrate gave 3,4,5- trisubstituted 1,2,4-triazole. Hydrazides were converted to substituted thiosemicarbazides by their reaction with ammonium thiocyanate, which then treated with sodium hydroxide solution to give 3,5 -disubstituted- 1,2,4-triazole. The structures of the synthesized compounds were established by physical and spectral methods.