Utility of Activated Nitriles in the Synthesis of Isoquinoline Derivatives

Abstract

γ-Cyano-γ-(4-pyridyl) pimelonitrile (2) has been prepared by cyanoethylation of 4-pyridyl-acetonitrile (1). Hydrolysis of (2) using dil. HCl afford γ- amido-γ-(4-pyridyl) pimelic acid (3) which cyclized to the corresponding 3-(4-pyridyl)-2, 6-piperidindione-3-propionic acid (4) by continuos heating in hydrochloric acid solution. Ring closure of (4) takes place in the presence of conc. sulphuric acid to give spiroisoquinoline derivative (5). Spiroisoquinoline derivatives (8) - (11) have been also prepared. Structure of all the products have been established by elemental and spectral analyses.