Process for the preparation of imidazo 4,5-b pyridine derivatives.

摘要

The invention provides a novel chemical process for the manufacture of certain imidazo[4,5-b]pyridine derivatives of the formula I wherein R<1>, R<2>, R<3> and R<4> have the various meanings defined herein, and their non-toxic salts, which are angiotensin II inhibitors. The process involves the removal of an electron-deficient phenyl group or a pyridyl or pyrimidyl group from a compound of the formula II as defined herein. Certain of the intermediates are novel and are provided as a further feature of the invention. <CHEM> a