Optically active maytansinoids and maytansinoid production method

摘要

Maytansinoid compounds are produced by (a) treating a compound of the formula <IMAGE> wherein alk is <IMAGE> -CH2CH2CH3 or <IMAGE> under conditions of reductive hydrolysis to yield maytinsinol; and (b) contacting the maytansinol with an acid of the formula <IMAGE> wherein R is lower alkyl, in the presence of a carbodiimide to yield a maytansinoid. In accordance with a second aspect of the invention there is provided a D-form maytansinoid with respect to the asymmetric center at the 2'-position having the formula: <IMAGE> wherein R is a lower alkyl group.