M. V. Sigalov

Synthesis of 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazepines and 4-amino-3-acylvinylthio-1,2,4-triazoles by reaction o acylacetylenes with 4-amino-3-mercapto-1,2,4-triazole

Abstract1,2,4-Triazolo[3,4-b]-1,3,4-thiadiazepines have been prepared by treating α-acetylenic ketones with 4-amino-3-mercapto-1,2,4-triazole in glacial acetic acid. Terminal acetylenic ketones react with the triazole to form 4-amino-3-acylvinylthio-1,2,4-triazoles. Heating the latter with hydrazine hydrate in alcohol yields substituted pyrazoles.

Synthesis of 1,3,4-thiadiazole derivatives by the reaction of thiosemicarbazide or its 1- or 4-substituted derivatives with some 1-bromo-2-acylacetylenes

The reaction of thiosemicarbazide, 4-methyl-, 4-phenyl-, or 1-phenylthiosemicarbazides with 1-bromo-2-benzoyl(thenoyl-2)acetylenes in acetonitrile or glacial acetic acid yielded 2-acylmethylene- and 2-acylmethyl-5-amino-1,3,4-thiadiazoles. Heating of the latter in alcohol or aqueous alcohol gave the free bases.

Interaction of thermal acylacetylenes with thiosemicarbazide and 4-methyl- and 4-phenylthiosemicarbazides

By the reaction of thiosemicarbazide and 4-methyl- and 4-phenylthiosemicarbazides with terminal α-acetylenic ketones, depending on the conditions, thiosemicarbazones of acylacetic aldehyde, 1,1-bis(acylvinyl)thiosemicarbazides,and5-phenylamino-2-acylmethyl-3-acylvinyl-1,3,4-thiadiazolinesareobtained. Ring-chain tautomerism of the 1,1-bis(acylvinyl)thiosemicarbazides has been investigated.

The reaction of terminal α-acetylenic ketones with thiosemicarbazones

The reaction of terminal α-acetylenic ketones with thiosemicarbazones gives a series of 5-amino-and 5~anilino-3-acylvinyl-Δ4-1,3,4-thiadiazolines. These products react with perchloric acid to give the corresponding perchlorates.

Synthesis of 1,3,4-thiazole derivatives by the reaction of thiobenzhydrazide with some acylacetylenes

Abstract2-Acylmethyl-5-phenyl- and 3-acylvinyl-2-acylmethyl-5-phenyl-1,3,4-thiadiazol-4-ines were obtained by the reaction of terminal α-acetylenic ketones with thiobenzhydrazide. Substituted acetylenic ketones react with thiobenzhydrazide in alcohol to give N,S-bis(acylvinyl)thiobenzhydrazides.

Reaction of 1-bromo-2-acylacetylenes with thiobenzhydrazide

ConclusionsThe reactions of 1-bromo-2-acylacetylenes with thiobenzhydrazide at from −10 to −30°C in ether, acetonitrile, methanol without catalyst, or methanol in the presence of triethylamine gave 2-acylmethyl-5-phenyl-1,3,4-thiadiazoles and their hydrobromide salts.

Reaction of methyl propiolate with thiosemicarbazones

Methyl propiolate reacts with thiosemicarbazones in methanol in the presence of triethylamine to give 2-benzylidene(thenylidene, or furfurlidene)azino-3H-1,3-thiazin-4-ones.

Reaction of 1-acyl-2-phenylacetylenes with thiosemicarbazide

ConclusionsThe reaction of 1-acyl-2-phenylacetylenes with thiosemicarbazide in methanol at 60‡C gives 2-amino-7-hydroxy-6,7-dihydro-1,3,4-thiadiazepines which, upon heating in -vacuum fragment with the formation of 3,5-disubstituted pyrazoles.