Synthesis of 1-aryl-3-phenethylamino-1-propanone hydrochlorides as possible potent cytotoxic agents

1-Aryl-3-phenethylamino-1-propanone hydrochlorides 1-10, which are potential potent cytotoxic agents, were synthesized via Mannich reactions using paraformaldehyde, phenethylamine hydrochloride as the amine component and acetophenone, 4'-methyl-, 4'methoxy-, 4'-chloro-, 4'-fluoro-, 4'-bromo-, 2',4'-dichloro-, 4'-nitro-, 4'-hydroxyacetophenone or 2-acetylthiophene as the ketone component. Yields were in the 87-98 % range. Of the compounds synthesized, compounds 2, 6-8 and 10 were new. The optimum reaction conditions were investigated by changing the mol ratios of the reactants, the solvents and the acidity levels using 1 and 10 as representative targets. It was observed that the best mol ratio of the ketone, paraformaldehyde and phenethylamine hydrochloride was 1:1.2:1 (compared with a 2:2.1 ratio), and the most suitable reaction medium was ethanol containing concentrated hydrochloric acid (compared with only ethanol or no solvent). This study may serve as a guide for the conditions of the reactions to synthesize compounds having similar chemical structures.