Synthesis of Two Aromatic Methylenedioxy-Substituted Colchicine Congeners: Elucidation of the Structure of Cornigerine as 2,3-(Methylenedioxy)-2,3-Didemethoxycolchicine

Article abstract of DOI:10.1021/jo00331a021

Treatment of colchicine with concentrated sulfuric acid at 80-90 deg C afforded besides 2-demethylcolchicine a mixture of catecholic colchicines which could be separated and identified.Similar treatment of 1-demethyl- and 3-demethylcolchicine gave predominantly the 1,2-catechol or its 2,3 isomer.Methylenation of these catechols afforded the colchicine congeners 1 and 10.A comparison with natural cornigerine revealed that the alkaloid was identical with the 2,3-methylenedioxy compound 10 and not with 1, as formerly proposed.