Facile Methods for Preparation of Thiazolopyridine and Tetrahydro-thiazolopyridine Derivatives

The improved routes to prepare tetrahydrothiazolo[5,4-c]-pyridine-2-carboxylic acid lithium salts (2 and 3) were developed. Route A is consisted of the improved preparation of thiazolopyridine intermediates, and Route B is applicable for a large scale synthesis of tetrahydrothiazolo[5,4-c]pyridine-2-carboxylic acid derivatives. The methods we developed may serve as facile means for preparing thiazolopyridine and tetrahydrothiazolopyridine derivatives.