Electrochemical oxidation of aromatic ethers. Part 11. The synthesis of phenanthropyrrolidines

Abstract

7a,8-Dihydro-3,10,11-trimethoxyphenanthro[8a,9-c]furan-2,7(5H)dione (5), obtained by electrochemical oxidation of 6,7-dimethoxy-4-(3,4-dimethoxybenzyl)isochroman-3-one, has been converted by reduction, treatment with propylamine, and further reduction into 2,3,4,5,6,7a,8,12b-octahydro-3,10,11-trimethoxy-6-propyl-1H-phenanthro[8a,9-c]pyrrol-2-ol (12). Anodic oxidation of 6,7-dimethoxy-4-(3,4-dimethoxyphenethyl)isochroman-3-one (18) affords 8,9-dihydro-2,11,12-tri-methoxybenzo[c]naphtho[1,2-d]pyran-3,7(5H,7aH)dione (26) which on reaction with methylamine yields 4a,5,7,8-tetrahydro-4a-hydroxymethyl-2,10,11-trimethoxy-5-methylnaphth[2,1-c]indole-3,6(4H,6aH)dione.