Development of Privileged Groebke-Blackburn-Type 4-(3-aminoimidazo [1,2-a]pyridin-2-yl)benzoic Acid Core into a Combinatorial Library on Solid Phase

A library of 4-(3-acyl- or carbamoylaminoimidazo[1,2-a]pyridin-2-yl)benzamides (8) was synthesized on solid phase. A suitably protected core acid (1) was synthesized in multigram quantity using previously published procedure and used as the acylating reagent for modifying a set of AMEBA resins. Subsequent liberation of the amino group (using a novel hydrazine procedure) and its acylation or carbamoylation provided, after cleavage, final products in higher chemical yields and purities compared to known protocols that include formation of the imidazo[1,2-a]pyridine core on solid support.