Preparation of the HIV Attachment Inhibitor BMS-663068. Part 5. Selective C‑7 Bromination of the 6‑Azaindole Core

We report research focused on the preparation of an advanced intermediate in the synthesis of a novel antiretroviral. This manuscript describes the development of an efficient oxidation of a 6-azaindole derivative, the bromination of the resulting N-oxide using PyBroP, the removal of the protecting group, and the isolation of the brominated azaindole product. The work reported herein has been successfully implemented in the multikilogram scale to fund development and clinical activities of BMS-663068.