SELECTIVE AND POTENT MONOAMINE-OXIDASE TYPE-B INHIBITORS - SUBSTITUTED SEMICARBAZONES AND ACYLHYDRAZONES OF AROMATIC-ALDEHYDES AND KETONES

The synthesis and the evaluation of the monoamine oxidase A and B inhi bitory activities of 21 new substituted acylhydrazones of various arom atic aldehydes and 4-(benzyloxy)acetophenone, and four substituted sem icarbazones of benzaldehyde and 4-(benzyloxy)benzaldehyde, are describ ed. The 4-(benzyloxy)phenyl group contributing to a high lipophilicity led to the most active compounds. One of these, compound 3g (IC50 = 3 nM, MAO A/MAO B selectivity > 33 000), was found to act as a reversib le and probably tight-binding inhibitor. The studied acyclic hydrazone s and semicarbazones are structurally related to other reversible and potent inhibitors, eg, heterocyclic compounds such as 1,3,4-oxadiazol- 2(3H)-one derivatives in which the hydrazono group is intracyclic. Som e of these new inhibitors might find use in the symptomatic treatment of neurodegenerative processes.