REACTION OF PHENOLS WITH ETHYL AZODICARBOXYLATE

The thermal reaction of some 2,4-, 2,6-, and 2,4,6-substituted phenols with ethyl azodicarboxylate has been studied. In general, both C-C coupling products derived from the phenoxy radicals as well as coupling products from the phenoxy and the hydrazodicarboxylate radicals are formed. The latter compounds were independently prepared by the acid-catalyzed addition of ethyl azodicarboxylate to the phenols. 2,4,6-Tri-t-butylphenol reacts with ethyl azodicarboxylate under surprisingly mild conditions with loss of a 2-t-butyl group to yield 1- (2-hydroxy-3,5-di-t-butyl)phenyl 1,2-ethyl hydrazodicarboxylate. No reaction is observed between azodicarboxylate and phenols of high oxidation potential such as 2-chloro-, 2,6-dichloro-, 2,6-dinitro-, or 2-chloro-6- phenylphenol. © 1969, American Chemical Society. All rights reserved.