Preparation of α‐(aminoalkyl) acrylic esters and their phthalimido substituted derivatives

Synthesis of α‐(aminoalkyl) acrylates has proceeded along the conventional malonic ester route. The amino structure was protected by the use of phthalimido derivatives with subsequent removal of the phthalate moiety to produce the desired esters. Ethyl α‐alkyl acrylates with phthalimido, phthalimidoethyl and phthalimidobutyl groups as the α‐substituent were prepared together with the phthalimidoethoxyethyl derivative. The esters were prepared in substantial purity but with some difficulty owing to their ease of polymerisation. Infra‐red spectra and polymerisability studies were carried out on the new α‐phthalimidoalkyl acrylates and are presented here. Hydrolysis (with hydrazine hydrate) of these intermediate esters to their corresponding α‐(aminoalkyl) acrylates was shown qualitatively using a modified ninhydrin test. It was necessary to develop a modified test procedure since excess hydrazine from the hydrolysis was found to interfere with the ninhydrin colour reaction.