Cascade Transformation of the Ansamycin Benzoquinone Core into Benzoxazole Influencing Anticancer Activity and Selectivity
Natalia Skrzypczak, Krystian Pyta, Wiktor Bohusz, Aleksandra Leśniewska, М. Gdaniec, Piotr Ruszkowski, Wojciech Schilf, Franz Bartl, Piotr Przybylski
Abstract
High Resolution Image Download MS PowerPoint Slide The metal-free cascade transformation of geldanamycin benzoquinone core is proposed at relatively mild conditions. This approach yields new benzoxazole ansamycin antibiotics and enables their functionalization in an atom-economic manner, irrespective of the type of amine used. The analysis of the heterocyclization course reveals the dependence of its rate on the nature of the para -substituent within the benzylamine moiety (EDG/EWG) and the strength of the base. The reduction of the ansamycin core enables an increase in anticancer potency and selectivity.