PREPARATION OF 17-AMINO-22-(4'-AZIDO-3'-125IODOPHENACYL)-17-DEMETHOXYGELDANAMYCIN .1. AN ANSAMYCIN FOR PHOTOAFFINITY-LABELING

An azido-125iodo-ansamycin (1) in the geldanamycin family was prepared in two steps in one reacton vessel from 17-amino-22-(4'-aminophenacyl)-17-demethoxygeldanamycin (3). The title compound was suitable for photoaffinity labeling proteins that interacted with ansamycins. A alternative synthesis is reported for preparation of unlabeled title compound in order to afford practical amounts of (1) for conventional biochemical studies.