O-Cyanophenols

Electron impact fragmentation studies on 1,2-benzisoxazoles and benzoxazole indicate that isomerization takes place before degradation. Shape analysis and metastable ion abundances in the mass spectra indicate that isomerization to o-cyanophenols occurred prior to degradation by loss of CO or NCH (75BSB207). 

K. Gewald and H. J. Jiinsch, J. Prakt. Chem. 315, 779 (1973). (novel general synthesis of 3-aininobenzofurans Gewakl s benzofuran synthesis, extended Rap method to o-cyanophenols). 

It is known that 3-aminobenzo[6]furan can be prepared from o-cyanophenols and a-halogenocarbonyl compounds with subsequent Thorpe cyclization (73JPR779). The extension of this synthesis to heteroatom substituted benzo[6]furans is straightforward (76JPR313). The reaction of potassium salts of 3-cyano-2-pyridones (e.g. 27) with a-halogenocarbonyl compounds (esters, ketones) yields 2-alkoxy-3-cyanopyridines which can be cyclized in the presence of sodium ethoxide to give 3-aminofuro[2,3-6]pyridines (Scheme 6). 

Thermolysis of 2-azidotropone (248) in boiling cyclohexane gave o-cyanophenol, whereas in protic solvents (methanol, water, aniline) the ring-opened products 250 were obtained Both may be... 

Analysis of metastable ion abundancies and shape has demonstrated that indoxazene isomerizes into o-cyanophenol prior to fragmentation in the mass spectrometer.37... 

In aqueous solution indoxazene-3-carboxylic acid undergoes slow but quantitative decarboxylation and ring cleavage to o-cyanophenol (t1/2 at 30°C, 7 days).53 From a careful study of substituent and solvent effects on the rate of decarboxylation, and on tritium labeling studies, it is concluded that the reaction involves an intermediateless, concerted loss of carbon dioxide via a transition state conveniently represented as 38, rather than by a stepwise process through carbanion 39 (Scheme 3).8,53... 

Potassium cyanide o-Cyanophenols from nitro compds. 

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