Heterocycles from Nitrile Oxides. Part IV. 1,2,4,5-Oxatriazines

Reaction of Nitrilimines and Nitrile Oxides with Hydrazines, Hydrazones and Oximes

“…A similar reaction was reported for the reaction of nitrile oxides with methylhydrazine to yield 11 [6,8].…”

“…Nitrilimines undergo 1,3-additions with phenyl-, acetyl-and benzoylhydrazines 7 leading to the acyclic adducts 8a or 8b [5]. The reaction of nitrile oxides with hydrazine hydrate was similarly reported to give hydrazidoximes [6].…”

“…The reaction with methylhydrazones of aromatic aldehydes and ketones 47 gave "ring-chain" tautomerism, where the tautomeric ratio was found to be dependent on the steric and electronic effects of the substituent at C-3, C-6 and N-4 [21]. The reaction of nitrile oxides with methylhydrazones 45 in chloroform was found to constitute a convenient synthetic route to the novel 4,5-dihydro-6H-1,2,4,5-oxatriazines 49 [6]. Risitano and coworkers obtained the triazoles directly from the appropriate monomethylhydrazones of aryl aldehydes in refluxing ether for 2 hours [22].…”

Reactions of N-alkylhydrazones of aliphatic ketones

“…Натомість при генерації нітрилоксидів in situ з гідроксамоїлхлоридів 110 під дією триетиламі-ну вони взаємодіють з метилгідразоном цикло-гексанону 19 із отриманням похідних тетрагід-рооксотриазину 111 [65] (схема 38).…”

Novel Syntheses of 5-Aminothieno[2,3-c]pyridazine, Pyrimido[4',5':4,5]thieno[2,3-c]pyridazine, Pyridazino[4',3':4,5]thieno-[3,2-d][1,2,3]triazine and Phthalazine Derivatives

“…In addition, 1,2,3triazine systems condensed with carbocycles or heterocycles are known to exhibit antiallergic activity. 9 On the basis of these reports and in continuation in the synthesis of novel condensed pyridazine derivatives, [10][11][12][13][14] we reported here the synthesis of 5-aminothieno [2,3-c]pyridazine, pyrimido [4',5': 4,5]thieno [2,3-c]pyridazine, pyridazino [4',5':4,5]thieno [3,2-d]- [1,2,3]triazine and phthalazine from 4-cyano-3-mercapto-6methyl-5-styryl-pyridazine 4 as starting material.…”