Studies on the synthesis and biological evaluation of the metabolite of clausenamide CM₂ and its stereoisomers.

The synthesis and biological evaluation of 5-hydroxy clausenamide (CM₂), one of the major metabolites of clausenamide, and its stereoisomers have been carried out. The absolute configurations of (-)- and (+)-CM₂ were assigned as 3S,4S,5S,6S and 3R,4R,5R,6R respectively based on (1)H NMR spectroscopic investigation and their chemical correlation to (-)- and (+)-clausenamidone (3). Electrophysiological assay showed that compound (+)-CM₂ and its C₆ epimer (+)-8a had significant effects on synaptic transmission and thus induced the long-term potentiation of the dentate gyrus.