The synthesis of 2-phenyl-3-aminopyridine, a key intermediate in the preparation of 2-phenyl-3-aminopiperidine, from 2-chloro-3-aminopyridine is described using an imine as a protecting group for an aminopyridine. The in situ protection of 2-chloro-3-aminopyridine with benzaldehyde followed by Suzuki coupling with phenylboronic acid and subsequent acid hydrolysis provided the titled compound in a single, high-yielding step from inexpensive and commercially available starting materials.

An Efficient and Cost-Effective Synthesis of 2-Phenyl-3-aminopyridine (III). -(III) is a potent synthon of biologically active compounds. -(CARON, STEPHANE; MASSETT, STEVE S.; BOGLE, DAVID E.; CASTALDI, MICHAEL J.; BRAISH, TAMIM F.; Org. Process Res. Dev. 5 (2001) 3, 254-256; Pfizer Global Res. Dev., Pfizer Inc., Groton, CT 06340, USA; EN)