Determination of reactivity constants of 5-substituted 2-indolyl groups by means of13C NMR

A series of 5-substituted 2-phenylindoles has been synthesized; the13C chemical shifts have been measured for these compounds in acetone, and these data have been used to determine the σI and σRO constants of the 5-substituted 2-indolyl groups. Relationships have been found for the estimation of the σ constants of any 5-substituted 2-indolyl group.