Abstract
A new synthesis of 1-alkyl-9, 10-dimethoxy-1, 2, 3, 4, 6, 7-hexahydro-11bH-benzo [a] quinolizin-2-ones (VIII) (5 specimens) was described. 3-(3, 4-Dimethoxyphenethylamino) propionitrile was acylated with the chloride of various ethyl alkylhydrogenmalonates followed by esterification to yield the corresponding diester-amides (V), which were cyclized by refluxing with phosphoryl chloride alone. The products were reduced to afford α-alkyl-2-(2-ethoxycarbonylethyl)-6, 7-dimethoxy-1, 2, 3, 4-tetrahydro-1-isoquinoline acetates (VI). The latter were cyclized with sodium hydride in boiling toluene according to Dieckmann's method and the products were submitted to ketonic fission to yield the ultimate products in rather a poor yield. 6, 7-Dimethoxy-3, 4-dihydroisoquinoline was the common by-product produced during the ketonic fission reaction.
