Regioselective synthesis of C-2 substituted imidazo[4,5-b]pyridines utilizing palladium catalysed C–N bond forming reactions with enolizable heterocycles

A Highly Efficient Catalyst for the Suzuki Cross-coupling Reaction of 3-Chloro-5-oxadiazol-2-yl Pyridine

“…Prepared from 3a and 4c using the general procedure, purification by flash column chromatography (50-55% ethyl acetate in petroleum ether) yielded product as white solid (40 mg 1, 150.4, 149.3, 146.1, 134.1, 133.1, 130.6, 127.5, 124.8, 119.3, 118.5, 114.9, 48.7, 16.9 For C 15 H 11 N 5 O: C,64.97;H,4.00;N,25.26%. Found: C,64.79;H,4.18;N,3, ,71.34;H,4.90;N,15.13%. Found: C,71.26;H,4.98;N,3,pyridin-3-yl)-N-(thiazol-2-yl)benzamide (5g).…”

“…Found: C,64.79;H,4.18;N,3, ,71.34;H,4.90;N,15.13%. Found: C,71.26;H,4.98;N,3,pyridin-3-yl)-N-(thiazol-2-yl)benzamide (5g).…”

“…For C 16 H 9 F 6 N 3 O: C,51.49;H,2.43;F,30.54;N,11.26%. Found: C,51.64;H,2.38;F,30.34;N,3,-5-(4-(5-methyl-1,3,4oxadiazol-2-yl)phenyl)pyridine (5l).…”

“…For C 17 H 13 N 5 O 2 : C,63.94;H,4.10;N,21.93%. Found: C,63.77;H,4.25;N,3,pyridin-3-yl)phenyl) (piperidin-1-yl)methanone (5m).…”

“…And among the various cross-coupling reactions, Suzuki-Miyaura reaction [2] has been considered as one of the effective methods in generating carboncarbon bonds. The cores of many types of polymers, ligands, natural products and pharmaceuticals contain biaryl rings [3]. The Suzuki-Miyaura coupling has many advantages over other methods for constructing these moieties due to their mild conditions, high tolerance towards functional groups, the commercial availability and stability of its reagents and the ease of handling and separating by-products from its reaction mixtures.…”