The o-cyanocinnamonitriles and related compounds

Abstract

Ring-scission reactions of 1-nitroso-2- and 2-nitroso-1-naphthol have been re-examined to obtain satisfactory routes to the o-cyanocinnamonitriles. New observations are made concerning these reactions and the different geometric stabilities of the various o-substituted cinnamic products. A coplanar anti-conformation for the o-substituted cis-cinnamonitriles is indicated by proton magnetic resonance results. In related experiments, ring-opening of phthalidyl-acetic acid and -acetonitrile is effected with base under mild conditions to give, respectively, o-carboxy-trans-cinnamic acid and a mixture of o-carboxy-cis- and -trans-cinnamonitriles, from which the cis-product is readily separated. The reason for these findings is discussed.