A new route to papaverine analogs via photocyclization of substituted N-acyl-alpha-dehydrophenylalaninamides

摘要

(Z)-N-Phenylacetyl-alpha-dehydro(3,4-dimethoxyphenyl)alaninamide derivatives [(Z)-1] were prepared in satisfactory yields, starting from 3,4-dimethoxybenzaldehyde. On irradiation in methanol, regioselective photocyclization of these derivatives proceeded to give papaverine analogs in good yields. Substituents introduced into (Z)-1 were found to exert only a minor effect on the conversion of the starting isomers (1) as well as on the selectivity of the analogs which were formed along with 1-azetines.