Hydrochloric Acid → 2-butyl-1H-imidazo[4,5-b]pyridine

Participants

Reaction Conditions

Reaction Steps

A mixture of 2-amino-3,5-dinitropyridine (5.32 g, 28.9 mmol), THF (100 mL), methanol (250 mL) and Raney-nickel (3 mL of a 1:1 suspension in H2O) was stirred under H2 (1 atm.) was stirred for 5 h. The reaction mixture was quickly filtered into a receiving flask containing 5 mL of conc. HCl and the solvent was removed in vacuo at r.t. To this crude 2,3,5-triaminopyridine.HCl was added valetic acid (9.43 mL, 86.7 mmol) and polyphosphoric acid (100 mL) and this mixture was heated to 95° C. for 6 h. The warmed mixture was poured into stirred ice-H2O (200 mL) and this mixture was cooled and neutralized (to pH 4) by the addition of conc. NH4OH. Extraction with EtOAc (3×75 mL), concentration, and purification (SiO2, 5% MeOH/EtOAc) gave 6-[(1-oxopentyl)amino)]-2-butylimidazo[4,5-b]pyridine as a solid. Step 3: Preparation of 2-butyl-3-[2'-(N-tert-butylaminosulfonyl)[1,1']-biphenyl-4-yl]methyl-6-[(1-oxopentyl)amino)]-3H-imidazo[4,5-b]pyridine

Provenance & Evidence