Derivatives of saquayamycins A and B. Regio- and diastereoselective addition of alcohols to the L-aculose moiety.

Abstract

In continuation of our structure-activity investigations on angucycline antibiotics we prepared derivatives of saquayamycins A (1) and B (4) by regio- and diastereoselective nucleophilic addition of different alcohols to the L-aculose moiety. Reversible protection of the 4'-hydroxy group in 1 by silylation allowed a derivatization at both L-aculose moieties without cyclization towards cinerulose B. The in vitro cytotoxic activity remained almost unchanged after variation at the L-aculose moieties whereas a change in the aglycone structure led to a total loss of the biological activity.