Studies on Steroidal Enol Ethers: Antigonadotrophic Activity of Cyclopentyl Derivatives of Some Orally Active Progestins

Abstract

Cyclopentyl enol ethers of some orally active progestational steroids have been compared with their parent compounds for their ability to inhibit hypersecretion of pituitary gonadotrophin in parabiotic rats (intact female\p=m-\ castrated male). Although in previous experiments enolic etherification altered the 'antioestrus' activity it did not change the antigonadotrophic potency either of 6\g=a\-methyl-17\g=a\-acetoxyprogesterone or 17\g=a\-ethynyl \x=req-\ 19-nortestosterone acetate. The lack of parallelism between antigonadotrophic and 'antioestrus' activities is discussed.

Biological Profile of Quingestanol Acetate

“…One of these compounds, 17~-ethynyl-19-nor-testosterone acetate 3-cyclopentyl enol ether3 belongs to the norandrostane series of progestational steroids and was found to be a potent antiestrual and contraceptive agent in rats (5) and as effective as its parent ketone, 1 7~e t h ynyl-19-nor-testosterone acetate (ENTA) in suppressing pituitary gonadotropin hypersecretion (4). The present paper presents data on other biological properties of this orally active progestogen.…”

The Biological Profile of Three 19-Nortestosterone-3-Cyclopentyl Enol Ethers

“…Though many studies on enol ether analogues of progesterone (2)(3)(4)(5)(6)(7) and certain androgens (2,7,(8)(9)(10)(11) have been reported, little is known about similar derivatives of 19-nortestosterone. Experiments with the 3-cyclopentyl enol ether of 17aethynyl-19-nortestosterone-l7p-acetate [ quingestanol acetate (QA)] showed that enol etherification generally enhances most biological activities as compared with its parent ketone (2,4,5,7,12). Substitution of a methyl or ethyl group for the ethynyl group and replacement of the acetate by a hydroxyl group has provided two additional enol ethers, 17a-methyl-19-nortestosterone-3-cyclopentyl enol ether (MCPE) and 17a-ethyl-19nortestosterone-3-cyclopentyl enol ether (EC PE) for this comparative study.…”