Collect. Czech. Chem. Commun. 1985, 50, 984-990

The synthesis of 2,3,7,8-bismethylenedioxy-11-methoxy-5-methylbenzo[c]phenanthridinium chloride

Jan Šmidrkala, Jiří Holubekb and Jan Trojánekb

a Research Institute for the Fat Industry, 269 01 Rakovnik
b Research Institute for Pharmacy and Biochemistry, 194 04 Prague 9


Acylation of 3-methoxy-6,7-methylenedioxy-l-methylaminonaphthalene (VI) with 6-bromo-2,3-methylenedioxybenzoyl chloride gave N-(3-methoxy-6,7-methylenedioxynaphth-l-yl)-N-methylamide of 6-bromo-2,3-methylenedioxybenzoic acid (IIIa) the irradiation of which with ultraviolet light in acetonitrile and triethylamine gave N-methyl-2,3-methylenedioxy-l-(3'-methoxy-6',7'-methylenedioxynaphth-l-yl)benzamide (Xa) in low yield in addition to 2,3,7,8-bismethylenedioxy-11-methoxy-5-methyl-6-oxobenzo(c)phenanthridine (Va). The last compound was converted to dihydro derivative VIa from which 2,3,7,8-bismethylenedioxy-11-methoxy-5-methylbenzo[c]-phenanthridinium chloride (Ia) was prepared. Chloride Ia differs from the alkaloid chelirubine (IIa) to which the structure Ia was assigned originally. Under analogous conditions irradiation of N-(3-methoxy-6,7-methylenedioxynaphth-l-yl)-N-methylamide of 6-bromo-2,3-dimethoxybenzoic acid (IIIb) leads to debrominated starting amide XIIIb on the one hand and to N-methyl-2,3-dimethoxy-l-(3'-methoxy-6',7'-methylenedioxynaphth-l-yl)benzamide (Xb) on the other. The expected phenanthridone derivative Vb could not be detected in the reaction mixture.