Benzotriazole-1-oxides

A new type of rearrangement has been reported for certain l-(o-nitrophenyl)pyrazoles (169), giving cis- and trans-benzotriazole 1-oxides (170 Scheme 12) (73TL891). The reaction was rationalized in terms of an intermediate azo compound (171 formed in turn either from the diradical species (172) or from the intramolecular 1,4-adduct (173). Subsequently... 

Dinitrohydroxykenzophenyltriazole, C, 2H7NgOg mw 301.22, N 23.25% not found in Beil, but its isomer 2-Phenyl-4,6-dinitro-benzotriazole- 1-oxide, It yel crysts, mp 195 6°, is listed in Beil 26,50... 

Oxidation of 1-hydroxybenzotriazole (446) in the absence of oxygen gave the benzotriazole 1-oxide radical (447), which, on reaction with DMAD, evolved nitrogen and formed the new radical 448.235... 

Although the possibility of anthranil-A-oxide formation may be recognized, there are certain difficulties in the way of accepting at least one of the foregoing examples. The two generalized systems (181 and 182) differ, in certain conformations, only in their electron distribution, and interconversion would be expected to occur so readily as to preclude isolation of other than the energetically more stable form. Several examples may be cited to bear this out. Thus, 2-phenyl-benzotriazole-1-oxide (181, X = N, Y = NPh) is well-known,320 but no evidence for the independent existence of o-nitrosoazobenzene (182, X = N, Y=NPh) is available. The rapid tautomerism of benzofuroxan (181, X = N, Y = 0) from the 1- to the 3-oxide structure, through... 

N-oxides can also be reduced. For example, the microbial deoxygenation of a series of aromatic and heteroaromatic N-oxide compounds, including quinoline N-oxides, isoquinoline N-oxides, 2-aryl-2H-benzotriazole 1-oxides, benzo[c]cinnoline N-oxide and azoxybenzene, has performed with bakers yeast-NaOH to afford quinolines and pyridines (291l... 

This study reports on the reactions of ambident nucleophiles with electron-deficient nitroaromatic and heteroaromatic substrates anionic complex formation or nucleophilic substitution result. Ambident behavior is observed in the case of phenoxide ion (O versus C attack) and aniline (N versus C attack). O or N attack is generally kinetically preferred, but C attack gives rise to stable thermodynamic control. Normal electrophiles such as 1,3,5-trinitrobenzene or picryl chloride are contrasted with superelectrophiles such as 4,6-dinitrobenzofuroxan or 4,6-dinitro-2-(2,4,6-trinitrophenyl)benzotriazole 1-oxide (PiDNBT), which give rise to exceptionally stable a complexes. Further interesting information was derived from the presence in PiDNBT of two electrophilic centers (C-7 and C-l ) susceptible to attack by the ambident nucleophilic reagent. The superelectrophiles are found to exhibit lesser selectivity toward different nucleophilic centers of ambident nucleophiles compared with normal electrophiles. 

Dinitro-2-(2,4,6-trinitrophenyl)benzotriazole 1-Oxide (PiDNBT) as an Ambident Superelectrophile... 

Photochemistry of N-heterocyclics Benzotriazole 1-oxide from pyrazole ring... 

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