Unambiguous structural assignment of monoanils of 3,4-pyridinedi- amine via regioselective synthesis

Abstract

Condensation of 3,4-pyridinediamine 1 with aromatic aldehydes results in the selective formation of the regioisomer 4-amino-3-benzylideneamino pyridine 2, which on reduction with NaBH 4 affords 3-benzylamino-4-aminopyridine 4. The structure of the compound 4 was established by an unambiguous synthesis of another regioisomer 3-amino-4-benzylaminopyridine 5 via another sequence of reactions. Based on the Regiospecific chemical synthesis of 5, the structures of 2 and 4 were established. The structures of all the new compounds have been confirmed by spectral studies (IR, 1 H NMR and Mass spectroscopy).