Triazol-3-ones

3-Triazol-4-ones (Anhydro-4-hydroxy-l,2,3-triazolium Hydroxides) (176) 

Four methods have been described for the synthesis of meso-ionic 

3- triazol-4-ones (176). Alkylation of either 1-substituted 4-hydroxy- 

Scarpati, D. Sica, and A. Lionetti, Gazz. Chim. Ital. 93, 90 (1963). 

Begtrup, K. Hansen, and C. Pedersen, Acta Chem. Scand. 21, 1234 (1967). 

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A number of general methods for the synthesis of meso-ionic 1,2,4-triazol-3-ones are available. Sodium ethoxide-catalyzed cyclization of 1-benzoyl-l,4-diphenylsemicarbazide (201, R = R = R = Ph, X = O) yielded anhydro-3-hydroxy-1,4,5-triphenyl-1,2,4-triazolium hydroxide (200, R = R = R = Ph). A general route to meso-ionic 1,2,4-triazol-3-ones (200) is exemplified by the formation of the 1,4,5-triphenyl derivative (200, R = R = R = Ph) from A-amino-MA -diphenylbenzamidine (202, R = R = R = Ph) and phosgene. In contrast with this ready meso-ionic compound formation, the corresponding reaction of the iV-methylbenzamidine (202, R = Me, R = R = Ph) did not yield the meso-ionic 1,2,4-triazol-3-one (200, R = Me, R = R = Ph). The product was in fact 3,4-diphenyl-2-methyl-l,2,4-triazol-5-onium chloride (203), which on heating gave 3,4-diphenyl-1,2,4-triazol-5-one (204, R = Ph). The formation of the A-methyl derivative (200, R = Me, R = R = Ph, yield 79%) by heating the 7V-thiobenzoyl semicarbazide (201, R = Me, R = R = Ph, X = S) with potassium carbonate in methyl cyanide has been reported. Another synthesis of A-methyl derivatives (200, R = Me) involves methylation of 3-methyl-4-phenyl-l,2,4-triazol-5-one (204,... 

NTO is synthesised in a two step process by reacting semicarbazide HCI with formic acid to obtain 1,2,4 triazole-5-one and followed by nitration to NTO. 

Nitro-4,6-bis-(3-nitro-lH-l,2,4-triazol-l-yl)pyiimidine 3-Nitro-1,2,4-triazole-5-one (NTO)... 

TRIAZOL-5-ONE, 3-NITRO- see NMP620 (l,2,4)TRIAZOLO(4,3-a)PYRIMIDINE see THT280 TRIAZOTION (RUSSIAN) see EKNOOO... 

LAH reduces 1,2,4-triazol-5-ones (267) to both triazoles (268) and triazolines (270). The course of the reaction depends on the nature of the N-substituent thus when R = H triazoles are formed in modest yield (15-30%), but when R = alkyl triazolium salts (269) are produced as intermediates and these are then reduced to triazolines (270 Scheme 22). ... 

Hydrazidoyl halides react with 2-amino[l,2,4]triazole to give 5-substituted 6-arylhydrazono-6//-imidazo[l,2-i][l,2,4]triazoles (350) and 6-arylhydrazono-5,6-dihydro-4//-imidazo[l,2-/>][ 1,2,4]-triazol-5-ones (351), respectively the latter products are not determined with respect to the tautomeric structures of the H-, 3H-, or 4/7-form (Scheme 32) <83JHC639>. 

K. -Y. Lee and M. M. Stinecipher, Propellants, Explosives, and Pyrotechnics, 14, 241 (1989). Handrick (Reference 2b) spoke of a salt link or correction of ca 67 kJmol associated with the formation of a salt from the reaction of an acid and base. From the enthalpy of formation of ethylenediamine from Pedley and of the ethylenediammonium salt of 3-nitro-l,2,4-triazol-5-one from the current reference, and the suggested salt link (x2), the enthalpy of formation of 3-nitro-1,2,4-triazol-5-one is predicted to be —135 kJ mol". This is in wonderful agreement with that reported in Reference 103. 

Xue, H., Gao, H., Twamley, B. and Shreeve, J.M., Energetic salts of 3-nitro-1,2,4-triazole-5-one, 5-nitroaminotetrazole, and other nitro-substituted azoles, Chem. Mater. 19 (7), 1731-1739 (2007). 

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