Assignment of configurations to adducts of 2-substituted anthracene with maleic anhydride by N.M.R. spectroscopy

Abstract

Isomeric adducts of 2-methylanthracene and maleic anhydride and of 2-aminoanthracene and maleic anhydride were prepared and their configurations determined by N.M.R. spectroscopy. The adducts were transformed into their N-aminoimide derivatives. N'-Substituents on the amino group were chosen so as to permit, because of their restricted rotation and non-planarity about the N-N' bond, an investigation into the magnetic effects of the cage moiety. When both the dienyl parts of the Diels-Alder adducts are almost identical, the N'-acetyl-N'-phenyl group has been found to be a diagnostic probe for the configurational studies. In N-(N'-acetyl-N'-aroy1amino)imide derivatives, the N'-aroyl group has been found to prefer an anti conformation while in the N?-acetyl- N'-phenyl group the N'-phenyl prefers the syn conformation.