Structure of Colchicine

Abstract

IN view of the remarkable physiological properties of colchicine its chemical nature is of some interest. Until recently, the structure (I) proposed by Windaus¹ has been generally accepted, although the stability of colchicine did not suggest a 9-amino-9: 10-dihydrophenanthrene system, and although the salicylaldehyde enol structure of ring C appeared fantastic. Cohen, Cook and Roe² have now provided evidence that ring B must be 7-membered, but the exact location of the acetamido group remains uncertain; the isolation by Windaus of 4-methoxyphthalimide from the oxidation product of acetylcolchinol methyl ether suggested that the group was adjacent to ring C, but Lettré and Fernholz³ have found that only β-anisylethylamine derivatives act as mitosis poisons.