Chemical Catalysis Guides Structural Identification for the Major Metabolite of the BET Inhibitor JQ1.

The bromodomain inhibitor (+)-JQ1 is a highly validated chemical probe; however, it exhibits poor pharmacokinetics. To guide efforts toward improving its pharmacological properties, we identified the (+)-JQ1 primary metabolite using chemical catalysis methods. Treatment of (+)-JQ1 with tetrabutylammonium decatungstate under photochemical conditions resulted in selective formation of an aldehyde at the 2-position of the thiophene ring [(+)-JQ1-CHO], which was further reduced to the 2-hydroxymethyl analog [(+)-JQ1-OH].