| Abstract: | Stobbe condensation of 2,3-dimethoxybenzaldehyde with diethyl succinate, followed by reduction and cyclization, gave 3-carbethoxy-5,6-dimethoxy-l-tetralone (7a). Subsequent reduction, aromatization and side chain conversion yielded the key intermediate 7,8-dimethoxy-2-naphthalenecarboxaldehyde (8c). 6,7-Dimethoxybenzg]isoquinoline (1) was prepared from 8c via condensation with nitromethane, reduction, formylation, cyclization, and aromatization reactions; the isomeric 8,9-dimethoxybenzg]isoquinoline (2) was obtained by the condensation of 8c with the diethyl acetal of aminoacetaldehyde (12) followed by reduction, tosylation, cyclization and aromatization. The methiodides of both compounds were also prepared. |
