- Ring Contraction of 2-Azidoquinoline and Quinoxaline 1-Oxides
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Thermal ring contraction of 2-azidoquinoline 1-oxide with loss of nitrogen did not lead to the desired 2-cyano-1-hydroxyindole.Instead, 2-cyanoisatogen (9), 2,2'-dicyano-3,3'-bis (10), and 2-aminoquinoline 1-oxide (7) were formed.The mechanism is believed to involve an intermolecular addition to the intermediate cis-o-nitrosocinnamonitrile formed in a concerted ring-opening nitrogen loss, i.e., not involving a nitrene intermediate.In accord with this, both 2-azido-4-methylquinoline 1-oxide and 2-azidoquinoxaline 1-oxide give the expected 2-cyano-1-hydroxy-3-methylindole (18) and 2-cyano-1-hydroxybenzimidazole (26), respectively.
- Abramovitch, Rudolph A.,Cue, Berkeley W.
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p. 5316 - 5319
(2007/10/02)
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