The reductive amination of carbonyl compounds to the corresponding amines by reaction with excess ammonium formate (Leuckart reaction) is a very useful procedure for the preparation of N-formyl derivatives of amines.
Ammonium carbonate and formic acid generate ammonium formate in situ, which in turn can dehydrate to furnish formamide. This can react with the carbonyl group of the 1-phenyl-2-propanone to form the imine, which can be reduced by formic acid, formamide and/or ammonium formate to form the N-formyl derivative of the corresponding amine.