New Aromatase Inhibitors. Synthesis and Biological Activity of Pyridyl-Substituted Tetralone Derivatives

J Med Chem. 1991 Sep;34(9):2685-91. doi: 10.1021/jm00113a004.

Abstract

The (E)-2-(4-pyridylmethylene)-1-tetralones 1-7 (1, H; 2, 5-OCH3; 3, 6-OCH3; 4, 7-OCH3; 5, 5-OH; 6, 6-OH; 7, 7-OH) were obtained by aldol condensation of the corresponding 1-tetralones with 4-pyridinecarboxaldehyde, and in the case of the OH compounds 5 and 7 subsequent ether cleavage of the OCH3-substituted 2-(4-pyridylmethylene)-1-tetralones. Catalytic hydrogenation of 1-4 gave the 2-(4-pyridylmethyl)-1-tetralones 8-11 (8, H; 9, 5-OCH3; 10, 6-OCH3; 11, 7-OCH3). Subsequent ether cleavage of 9-11 led to the corresponding OH compounds 12-14 (12, 5-OH; 13, 6-OH; 14, 7-OH). The enantiomers of 11 and 12 were separated semipreparatively by HPLC on triacetylcellulose. All compounds (1-14) showed an inhibition of human placental aromatase exhibiting relative potencies from 2.2 to 213 [compounds 6 and (+)-12, respectively; aromatase inhibitory potency of aminoglutethimide (AG) = 1]. The compounds exhibited no or only a weak inhibition of desmolase [cholesterol side chain cleavage enzyme; maximum activity shown by 12, 23% inhibition (25 microM); AG, 53% inhibition (25 microM)]. In vivo, however, the compounds were not superior to AG as far as the reduction of the plasma estradiol concentration and the mammary carcinoma (MC) inhibiting properties are concerned (PMSG-primed SD rats as well as DMBA-induced MC of the SD rat, pre- and postmenopausal experiments, and the transplantable MXT-MC of the BD2F1 mouse). This is due to a fast decrease of the plasma E2 concentration inhibiting effect as could be shown by a kinetic experiment. In addition, select compounds inhibited rat ovarian aromatase much less than human placental aromatase (12, factor of 10). Estrogenic effects as a cause for the poor in vivo activity of the test compounds could be excluded, since they did not show affinity for the estrogen receptor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aromatase Inhibitors*
  • Chromatography, High Pressure Liquid
  • Female
  • Humans
  • Lyases / antagonists & inhibitors
  • Magnetic Resonance Spectroscopy
  • Mammary Neoplasms, Experimental / drug therapy
  • Mice
  • Ovary / drug effects
  • Ovary / metabolism
  • Placenta / enzymology
  • Pregnancy
  • Pyridines / chemical synthesis
  • Pyridines / pharmacology*
  • Rats
  • Tetrahydronaphthalenes / chemical synthesis
  • Tetrahydronaphthalenes / pharmacology*

Substances

  • Aromatase Inhibitors
  • Pyridines
  • Tetrahydronaphthalenes
  • Lyases