Pyrazolo benzotriazines

Cyclization of pyrazole 220 (R = NH2), obtained from the reaction of 2-nitophenylhydrazine with 219 and subsequent hydrogenation, gave (81USP4260751) pyrazolo[l,2-al[l,2,4]benzotriazines 221, a useful antiinflammatory agent (Scheme 49). 

CN 5-(dimethylamino)-9-methyl-2-propyl-l/7-pyrazolo[ 1,2-a][ 1,2,4]benzotriazine-1,3(2//)-dione... 

Pyrazolo[l,2- ][l,2,4]triazolo[3,4-f][l,2,4]benzotriazines 485-487, containing the title substmcture, can be prepared by application of a well-known strategy using 1,3-dipolar cycloaddition to suitable azomethine imines... 

Cycloaddition of 4-phenyl-1,2,3-benzotriazine (94) to diphenylcyclo-propenone gave, among other products, the pyrazolo[l,5-a]quinazoline (95) (80CC808). 

Reactions which can be considered as cycloadditions are rare in the 1,2,3-triazine field. 4-Substituted 1,2,3-benzotriazines (2) react with diphenylcyclopropenone to give one, two or three of the following products pyrazolo[l,2-a][l,2,3]benzotriazin-l-ones (69), pyrazolo[l,2-a][l,2,3]benzotriazin-3-ones (70) or pyrazolo[2,3-a ]quinazolines (71) (80CC808). 

Chemical Name 5-(Dimethylamino)-9-methyl-2-propyl-lH-pyrazolo[l,2-a][l,2,4]benzotriazine-l,3(2H)-dione... 

With diphenylcyclopropenone 17,1,2,3-benzotriazines 16 gave one, two or three of the following cycloadducts pyrazolo[l,2- ][l,2,3]benzotriazin-1-ones 18, pyrazolo[l,2- ][l,2,3]benzotri-azin-3-ones 19, or pyrazolo[2,3- ]quinazolin-3-ones 20. The latter products require rearrangement of a [3 + 2] cycloadduct resulting from addition of the 1,2,3-benzotriazine to the 2,3-bond of 17.292... 

Only benzo derivatives of pyrazolo[l,2-a][l,2,3]triazine are known. 4-Phenyl-l,2,3-benzotriazine reacts with diphenylcyclopropenone to give several possible products, two of them being of this type (Equation (61)) <80CC808>. 

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