Imidazo -1,2,3-triazines

Diazoimidazoles coupled with )8-dicarbonyl compounds to give the azo compounds that, upon heating, cyclized to imidazo-triazine (76JMC517). 4-Diazoimidazole-5-carboxamide (9a) (Scheme 63) reacted with /3-dicarbonyl compounds, but the cyclization to 2-azahypoxanthine... 

The IC50 values found for the 5 -0-triphosphate derivatives of two other C-nucleosides i.e. imidazotriazine adenosine (21) and imidazo-triazine guanosine (22) show they are also well recognised by the NS5B polymerase. 

The formal derivation of the analogs, described in the foregoing, represents, from the point of view of systematic organic chemistry, a shift to the derivatives of other heterocyclic systems. In the case of pyrimidine aza analogs we arc dealing with derivatives of symmetrical or asymmetrical triazine in the case of purine aza analogs, the derivatives produced are those of imidazo[4,5]-i -triazine and z -triazolo [4,5-d] pyrimidine. 

The systematic nomenclature used originally the term imidazo-1,2,3-triazine. The Chemical Abstracts indexes use the more accurate name imidazo[4,5-d]-Z -triazine (141). The numbering of the substituents is different in the two systems of nomenclature as may be seen in the formulas. 

Imidazo[l,2-6]acenaphtheno[l,2-e][l,2,4]triazines 423 and 424 were prepared (78KGS1565) in a manner similar to that used for simple com-... 

The absorption and luminescence spectra of imidazo[ 1,2,4]triazines and related compounds were recorded. The phenyl groups on both the 6-and the 7-positions quenched the luminescence. An acceptor substituent such as CHO in position-7 sharply reduced the luminescence quantum yield (82MI4). A detailed study of the infrared spectra of imidazotriazines was carried out (75T433). 

Imidazo[l,2-c/][l,2,4]triazines 488 were prepared (78USP4096257) from the reaction of 2-imidazocarboxylic acid hydrazide 487 with orthoesters. They inhibited cyclic-AMP phosphodiesterase in the mouse skin phosphodiesterase test and had antiasthina. 

Imidazo[l,5-t/)[l, 2,4]triazin-l(2//)-ones 504 were prepared (78-USP4115572 79JHC277 88USP4743586) by the cyclization of hydrazide 503 with triethyl orthoesters. l,2,3,4-Tetrahydro-2,4,4-trimethyl-8-nitroimidazo[ 1,5-t/J[ 1,2,4]triazin-1 -one 506 was isolated as a byproduct during the course of purification of hydrazide 505, whose structure was determined (91MI4) by crystal structure analysis. They had antiasthmatic... 

Triphenylphosphoranylidenamino)-arylidineamino]imidazoles 546 with alkyl or arylisocyanates gave (89S843) imidazo[5,l-/][l,2,4]triazines 547 (Scheme 113). 

Imidazo[4,S-J]l,2,3-triazines and pyrazolo[3,4-Similar reactions have been used to obtain imidazopytidazines <95JHC1417, 1423 >. 

The oxazolotriazinone 88 undergoes ring transformation when treated with ammonia or with primary amines to give imidazo[l,2-f>][l,2,4]triazines 89. SimUar treatment with hydrazine yields triazino[4,3-ft][l,2,4]triazines 90 <95MI07 96CA(125)202176>. 

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