Chlorine as an activating group in an electrophilic substitution. The Friedel–Crafts acetylation of 1-chloronaphthalene

Abstract

In the Friedel–Crafts acetylation of 1-chloronaphthalene all the seven monoketone isomers are formed, with 1-acetyl-4-chloronaphthalene usually predominating. In nitrobenzene solution the 2-, 6-, and 7-isomers are obtained in substantial amounts (10–30%). From competitive acetylations at 20 °C, and each reactant at 0.062 5 mol dm^–3, relative reactivities of naphthyl positions could be determined : in chloroform, 1- 1.00, 2- 0.45, 1-chloro-2- 0.23, 1-chloro-3- 0.16, 1-chloro-4- 5.1, 1-chloro-5- 0.28, 1-chloro-6- 0.31, 1-chloro-7- 0.28, and 1-chloro-8- 0.039; or, in nitromethane, 1.00, 4.1, 4.5, 0.011, 13, 0.76, 1.5, 1.5, and 0.65, respectively. This provides an example of activation towards electrophilic substitution by a chloro-substituent.