SEROTONIN 5-HT4 RECEPTOR AGONISTIC ACTIVITY OF THE OPTICAL ISOMERS OF(+ O-2,3-DIHYDRO-2-METHYLBENZO[B]FURAN-7-CARBOXAMIDE/

The enantiomers, (R)-(-)-1 and (S)-(+)-1, of ro-2,3-dihydro-2-methylbe nzo[b]furan-7-carboxamide [(+/-)-1] were prepared from optically activ e benzyl no-2,3-dihydro-2-methylbenzo[b]furan-7-carboxylate [(R)-(+)-6 , (S)-(-)-6], respectively. The requisite (R)-(+)-6 and (S)-(-)-6 were prepared by large-scale preparative HPLC on chiral stationary phases (CSPs). The absolute configuration of (S)-(+)-1 was determined by sing le crystal X-ray analysis. The serotonin 5-HT4 receptor agonistic acti vity of (S)-(-)-1 hemifumarate (SK-951) which was hemifumarate of (S)- (+)-1 was about twice that of the other enantiomer (R)-(+)-1 hemifumar ate which was hemifumarate of (R)-(-)-1.