Synthesis of 4-acetylcolchicine

The synthesis of 4-acetylcolchicine ( 1 ) by Swern dehydrogenation of the corresponding mixture of 4-(R)-1-hydroxyethyl]- and 4-(S)-1-hydroxyethyl]colchicine ( 3a and 3b , respectively) is described (cf. Scheme). The X-ray analysis of 1 (cf. Fig.), crystallized from MeOH, showed the presence of MeOH in the crystals.