1.2.4- Benzotriazin-7-ones

From the above discussion it is evident that alkylation of 1,2,3-benzotriazin-4-one results almost entirely in substitution at Nj and/or Nj, and that alkylation on oxygen is at most a minor reaction. Alkylation of l,2,3-benzotriazine-4(3//)-thione (39, R = H), on the other hand, leads to predominant or exclusive substitution on sulfur, presumably as a result of the greater nucleophilicity of sulfur compared to oxygen. This difference in reactivity between the oxygen (10, R = H) and sulfur (39, R = H) compounds has been elegantly demonstrated by Murray and Vaughan. Treatment of the sodium salt of 10, R = H, with phenacyl bromide gives the Nj-substituted derivative 127, which, on... 

A-Aminopyridones can be oxidized to nitrenes. Thus, 3-amino-1,2,3-benzotriazin-4-ones (977) with lead tetraacetate lead to an intermediate nitrene (978), which can lose one or two molecules of nitrogen. 

Smalley and co-workers obtained the pyrido[2,l- i]quinazolin-l l-one 286 through the thermal decomposition of 3-(2-pyridyl)-1,2,3-benzotriazin-4-one (284) in 1-methylnaphthalene. The pyrido[2,l-i]quinazolinone 286 probably arises from the benzazetinone-iminoketene intermediate 285. Photodecomposition of the benzotriazinone 284 in tetrahydrofuran was very slow. Irradiation for 72 hr furnished the pyridoquinazolinone 286 in less than 5% yield along with the unchanged benzotriazinone 284. 

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