Indoles. V. Syntheses and Reactions of Cycloalkanon-[c, d] indole Derivatives

抄録

A convenient synthetic method for cycloalkanon [c, d] indoles (1 and 8) and some of their reactions were examined. The Friedel-Crafts reaction of 1-acetylindol-3-ylpropionic acids (4b and 4c) gave cyclopent [b] indoles (5b and 5c). This result indicates the general tendency of cyclization of 1-acetylindol-3-ylalkanoic acid, different from only one example reported previously by Szmuszkovicz, who prepared benz [c, d] indole derivative (3) from 1-acetylindol-3-ylsuccinic anhydride (2). The Friedel-Crafts reaction of 2-ethoxycarbonylindol-3-ylalkanoic acids (7b, 7c, and 7b), which were obtained in a good yield from easily available starting materials, gave cycloalkanon [c, d] indoles (8a, 8c, and 8e) in 24, 66, and 73% yield, respectively. Saponification and decarboxylation of 8a and 8e gave Uhle's ketone (1a) and a new ketone (1b), respectively. The Beckmann rearrangement of oximes (9a and 9b) with polyphosphoric acid gave lactams (10a and 10b) resulting from aryl migration. This is different from Bowman's example, in which lactams (11a and 11b) resulting from alkyl migration are obtained by the Beckmann rearrangement of oximes (9c and 9b) with thionyl chloride. Saponification and decarboxylation of 10a and 10b gave azepino [c, d] indolone (10c) and azocino-[c, d] indolone (10d) in 50 and 55% yield, respectively. 5-(3-Ethoxycarbonyl-5-oxo-2-pyrrolin-1-yl)-6 (1H)-oxo-3, 4, 5, 6-tetrahydrocyclohept-[c, d] indole (15b) was obtained from 1b by Stoll's method and its structure was elucidated from its nuclear magnetic resonance and mass spectra.