Anomalies in the Reduction of the Schiff Bases 5-(Diethylamino)-2-(phenyliminomethyl)phenol and 2-[(4-Diethylaminophenyl)iminomethyl]-phenol and Their Crystal Structures

Abstract

Two intermediate Schiff bases, 5-( diethylamino )-2-( phenyliminomethyl )phenol(1) and 2-[(4-diethylaminophenyl) iminomethyl ]phenol(2), were encountered which proved difficult to reduce to their corresponding secondary amines with sodium borohydride . X-Ray crystallographic analyses showed that the molecules are virtually planar with intramolecular hydrogen bonding between the imino nitrogen and the phenolic oxygen. Bond lengths in the phenyl rings with the diethylamino substituents indicate a significant contribution from the quinonoid form for these ring systems.