STUDIES ON NEW DERIVATIVES OF EPSILON-CAPROLACTAM

β-Carboxymethylcaprolactam has been synthesized by a sequence of reactions that comprised dehydrobromination of α-bromocaprolactam, Michael reaction with diethyl malonate with the product of this dehydrobromination, hydrolysis of the resulting β-(dicarbethoxymethyl)caprolactam, and decarboxylation of the β-(dicarboxymethyl)caprolactam. The dehydrobromination yielded a mixture of 1,3,6,7-tetrahydro-2H-azepin-2-one and 1,5,6,7-tetrahydro-2H-azepin-2-one. The structures of these compounds were investigated and verified by spectral studies. Both isomers participated as an acceptor in typical 1,4 additions that resulted in identical reaction products. These results have been explained by a shift of the double bond from the β,γ to the α,β position under the employed reaction conditions. A mechanism for the formation of the two isomers has been suggested. © 1969, American Chemical Society. All rights reserved.