3-Amino-6-hydrazino-l,2,4-triazin-5-one

Azido-2H-l,2,4-triazin-3-ones (56a) also cyclize to give the tetrazolo[5,l-d]-[l,2,4]triazin-3-ones (56b) (71RRC135, 71RRC311). Nitrosation of 3-amino-6-hydrazino-l,2,4-triazin-5-one (57) affords a compound which exhibits an intense absorption at 2140cm-1, showing that the 6-azido tautomer (58a) was isolated. When this compound was stirred for a few minutes in a polar solvent it quantitatively formed the tetrazole tautomer (58b) (79JHC555). 

Coupling of [2-(benzoyloxy)ethoxy]acetic acid (809) or [2-(l,3-diben-zoyloxy)propoxy]acetic acid 829 with 3-amino-6-hydrazino-l,2,4-triazin-5-one gave the two amides 827 and 830, respeetively. Thermal cyclodehydration of 827 and 830 and subsequent deprotection gave the two truncated-sugar acyclo C-nucleosides 828 (84JHC697) and 831 (95MI6) (Scheme 217). 

Equation (36)) <84JHC697>. Similarly, 3-Amino-6-hydrazino-l,2,4-triazin-5-ones (311) condense with carboxylic acids to give l,2,4-triazolo[3,4-/][l,2,4]triazin-8(7//) Ones (312) (Equation (37)) <84JHC697>. 

Reaction of 3-amino-6-hydrazino-l,2,4-triazin-5(2/f)-one (368) with nitrous acid has produced (369) as a representative of this class of compounds (79JHC555). 

The reaction of 3-amino-6-bromo-l,2,4-triazin-5-one with hydrazines results in 6-hydrazino-substituted l,2,4-triazin-5-ones (Scheme 57). No indication for substitution at C-5 has been observed (75CCC2680). 

The IR spectra of Co(ll,lll) and Cu(ii) complexes of hydrazones obtained by the reaction of 5,6-diphenyl-3-hydrazino-l,2,4-triazine with furfural <2002TML398> and 2-acetylpyridine <2004JCR105> have been studied to determine the coordination sites of these ligands. In addition, Mn(ii), Ni(ii), and Cu(ll) complexes of hydrazones derived from 4-amino-3-mercapto-6-methyl-l,2,4-triazin-5(4//)-one were elucidated by IR spectra <2000SRI979>. 

Reaction of 6-amino-5-hydrazino-l,2,4-triazin-3-one (321) with orthocarboxylates affords the... 

Amino-5-hydrazino-[l, 2,4]-triazin-3(2H)-one (242) reacts with orthoesters and concentrated acid to give a mixture of ring-closed and open—chain derivatives which are converted in warm acid to the s-triazolotriazines (244) by a regiospecific ring-closure at N-4 of the [1,2,4]-triazine ring and subsequent Dimroth-type... 

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