- RING-CHAIN AND RING-LINEAR-RING TAUTOMERISM IN THIOCARBONOHYDRAZONES
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The structure of the thiocarbonohydrazones of monocarbonyl compounds was studied by 1H and 13C NMR spectroscopy in solutions and by mass spectrometry in the gas phase. In solutions, irrespective of the substitution in the aromatic ring and in the hydrazine fragment, the thiocarbonohydrazones of aromatic aldehydes exist in the linear form, whereas the 2- and 5-substituted thiocarbonohydrazones of ketones are susceptible to ring-chain tautomerism: Thiocarbonohydrazone - 4-amino-1,2,4-triazolidine-3-thione. Those not having substituents at the nitrogen atoms are susceptible to ring-linear-ring equilibria: Hexahydro-1,2,4,5-tetrazine-3-thione - thiocarbonohydrazone - 4-amino-1,2,4-triazolidine-3-thione. In the gas phase under conditions of high vacuum, according to the mass spectra, the coexistence of four tautomeric forms (linear, tetrazine, triazolidine, and 2-hydrazino-1,3,4-thiadiazolidine) is possible in individual cases.
- Alekseev, V. V.,Zelenin, K. N.,Terent'ev, P. B.,Lashin, V. V.,Khorseeva, L. A.,Bulakhov, G. A.
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p. 491 - 501
(2007/10/02)
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- Investigation on the reaction of 4-anilino-5-mercapto-s-triazoles with pyrazolines and barbituric acids
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Synthesis of new 4-anilino-5-mercapto-3-substituted-1,2,4-triazoles (III) has been described.Reaction of III with 4,4-dibromo-substituted-pyrazolin-5-ones (VIII) affords 3,3'-substituted-5-phenyl-s-triazolothiadiazolidin-spiropyrazolin-5-ones
- Chande, Madhukar S.,Bhandari, Jayesh D.,Joshi, Vishwas R.
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p. 1218 - 1228
(2007/10/02)
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- Derives de la dihydro-2,4 triazole-1,2,4 thione-3 et de l'amino-2 thiadiazole-1,3,4 a partir de nouvelles thiosemicarbazones d'esters
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A new general synthesis of 4,5-disubstituted 2,4-dihydro-1,2,3-triazole-3-thiones is proposed.These heterocycles are obtained by the action of primary amines, aralhydrazines or aroylhydrazines on the thiosemicarbazones of esters.These last compounds are prepared by action of chlorhydrates of iminoesters on thiosemicarbazide in dimethylformamide.These thiosemicarbazones react also with strong acids, acid anhydrides and chlorides; by thermolysis and they give 2-amino-1,3,4-thiadiazole derivatives.Also, two derivatives of 1,2,4-triazolo-1,3,4-thiadiazole have been prepared.
- Malbec, Frederique,Milcent, Rene,Barbier, Geo
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p. 1689 - 1698
(2007/10/02)
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