Collect. Czech. Chem. Commun. 1985, 50, 861-868

Attempts at the synthesis of 11-methoxysubstituted benzo[c]phenantridines

Jan Šmidrkal, Jiří Holubek, Jiří Šlanger and Jan Trojánek

Research Institute for Pharmacy and Biochemistry, 194 04 Prague 9


Experiments aimed at the synthesis of so far unknown 11-methoxybenzo[c]phenanthridines (IIa,b,c) are described. In the first approach 2,3,7,8-tetramethoxybenzo[c]phenanthridine-11-carboxylic acid (IIIb) was synthesized using a procedure for the preparation of 2,3,7,8-bis-methylenedioxybenzo[c]phenanthridine-11-carboxylic acid (IIIa). Attempts to convert the carboxyl group of these acids to the methoxyl group were not successful. In the second approach 3-methoxy-6,7-methylenedioxy-l-methylaminonaphthalene (XX) was prepared from l-(3,4-rnethylenedioxyphenyl)-2-propanone (IX) by a multistep synthesis. On acylation of the product with 2,3-dimethoxy-6-nitrobenzoic acid and subsequent hydrogenation N-(3-rnethoxy-6,7-methylenedioxynaphth-l-yl)-N-methylamide of 6-amino-2,3-dimethoxybenzoic acid (XXII) was obtained. The attempts at its cyclization according to Pschorr were unsuccessful.