BILN2061 synthesis: Development of practical processes for the synthesis of the quinoline subunit and its coupling to the macrocyclic core

ORGN 410

Rogelio P. Frutos, rfrutos@rdg.boehringer-ingelheim.com, Pierre Beaulieu, Vittorio Farina, Michael Johnson, Nizar Haddad, Ioannis Houpis, Nathan Yee, and Chris Senanayake. Department of Chemical Development, Boehringer Ingelheim Pharmaceuticals, Inc, P.O. Box 368, 900 Ridgebury Rd., Ridgefield, CT 06877-0368
An integral part of our program to develop a practical, convergent and safe process for the synthesis of HCV (Hepatitis C Virus) protease inhibitor BILN2061 (1) was the development of suitable processes for the multi-kilogram preparation of its individual components, such as quinoline 3. Herein, we describe the development of an efficient, safe and practical process for the synthesis of 7-Methoxy-2-(2-amino-4-thiazolyl)-quinoline (3) and its coupling to macrocycle (2). Our new process for the synthesis of 3 allowed for a more convergent approach to BILN2061 (1) and eliminated the use of potentially dangerous reagents such as diazomethane used in the Medicinal Chemistry approach. Key aspects of the work described here are the optimization of the reaction conditions for the acetylation of m-anisidine via a Sugasawa reaction, as well as the optimization of the coupling of 2 and 3 by means of a brosylate displacement. Development of a process for the efficient synthesis of 3 allowed for the subsequent preparation of BILN2061 (1) in multi-kilogram amounts for toxicology, formulation and clinical studies.