Resolution, molecular structure and biological activities of the D- and L-enantiomers of potent anti-implantation agent, DL-2-[4-(2-piperidinoethoxy)phenyl]-3-phenyl-2H-1-benzopyran

Compound 1 (DL-2-[4-(2-piperidinoethoxy)phenyl]-3-phenyl-2H-1-benzopyran, C DRI 85/287) a potent anti-estrogen and anti-implantation agent has been suc cessfully resolved into its pure D- and L-enantiomers. Biological studies s howed L-enantiomer to be the active form, exhibiting a fivefold higher rece ptor affinity for the rat uterine cytosolic estrogen receptor, 100% contrac eptive efficacy at 1.3 mg/kg dose in single day schedule and 89% inhibition of estradiol induced increase of uterine weight at its contraceptive dose. The absolute stereochemistry determined by X-ray crystallographic analysis showed that the L-enantiomer has 2R configuration at its asymmetric centre . (C) 1999 Elsevier Science Ltd. All rights reserved.