A Simple Method of Protecting a Secondary Amine with Tert Butyloxycarbonyl (Boc) in the Presence of a Primary Amine

A simple method for chemically differentiating primary and secondary amines is described in which the primary amine is condensed with benzaldehyde to form an imine leaving the secondary amine available to be protected with BOC. The imine is then hydrolyzed to provide the free primary amine.