Crystal structure of doisynolic acid and the structure of other products formed during its synthesis

Base promoted air oxidation of 13beta-ethyl-11-methylenegon-4-en-17-one

The structure of 13-ethyl-11-methylene-18,19-dinor-17alpha-pregn-4-en-20-yn-16beta,17-diol (3, 16beta-OH desogestrel), a by-product obtained in the last step of the synthesis of desogestrel (1) by reaction of monolithium acetylide-ethylenediamine complex with 13beta-ethyl-11-methylenegon-4-en-17-one (2), is here reported. The structural assignments were supported by NMR 1H-, 13C-, 1H-1H COSY, 1H-13C HSQC, COLOC) and mass spectroscopy, and the configuration at the C-16 and C-17 stereocentres was established by X-ray crystallography. When the same 17-ketoderivative 2 was treated with a non-alkylating base, such as potassium tert-butoxide, instead of the expected 16-hydroxylated ketone, a dimeric product, 13beta-ethyl-16-[2'-(des-D-13"-carboxy-13"beta-ethyl-11"-methylenegon-4"-en-14"-yl)-ethyliden]-11-methylenegon-4-en-17-one (4), was isolated in good yield; it was characterized by NMR, mass, ultraviolet spectroscopy, and chemical transformations. Compounds 3 and 4 originate from the high reactivity of the 16-methylenic position of the 17-keto substrate (2) toward molecular oxygen under basic conditions.

Absolute structure determination of the highly biologically active bisdehydrodoisynolic acids

In a project designed to relate the unexpected in vivo and in vitro properties exhibited by (+)- and (-)-bisdehydrodoisynolic acid with their absolute stereochemical structure, an X-ray crystal-structure analysis was undertaken of the highly estrogenic, poorly binding (-) enantiomer. (1) and (13)C NMR spectra are also reported for the first time. The crystal structure shows the cis juxtaposition of the carboxyl and ethyl groups, which are separated by a large torsion angle, and that only the carbon atom holding the carboxyl group is out of the plane in which the remainder of the fused three-ring moiety lies. The crystal structure, which unequivocally characterizes the (-) enantiomer as cis-13(S),14(R) and, implicitly, the (+) enantiomer as cis-13(R),14(S), will be useful in continued studies aimed at explaining the selective estrogen receptor modulation (SERM) of these enantiomers which, in some cases, produces significantly different end-organ effects compared to those of estradiol, in both males and females, affording the promise of a variety of therapeutic and pharmacologic applications.

Ergosteroids III. Syntheses and biological activity of seco-steroids related to dehydroepiandrosterone

The unusual activity of some D-ring-seco estrogens led us to prepare several seco steroids related to dehydroepiandrosterone (DHEA) and to test for their ability to mimic thyroid hormone and 7-oxo-DHEA (1) as inducers of thermogenic enzymes in rats' livers. Only one, 3 beta-acetoxy-17a-oxa-androst-5-ene-7,17-dione (17), was capable of inducing both mitochondrial glycerophosphate dehydrogenase and malic enzyme. The closely related 3 beta-hydroxy-17a-oxa-androsta-5,15-diene-7,17-diones (both 14 alpha and 14 beta, 14 and 15) induce the formation of malic enzyme but not of glycerophosphate dehydrogenase. The 3 beta-propionyl ester of the above 14 alpha steroid was not active, presumably because it was not deacylated in vivo. The 16,17 dicarboxylic acid (9) produced by opening the D-ring also induced the formation of malic enzyme but not of glycerophosphate dehydrogenase. 3 beta-Acetoxyandrost-5-ene-7,16,17-trione, an intermediate in the synthesis of D-ring seco compounds enhanced the formation of both enzymes. Twelve other D-ring seco compounds were not active. Seco androstanes oxygenated at position 7 and with expanded A or B rings were not active.

Synthesis, estrogen receptor binding, and tissue distribution of [18F]fluorodoisynolic acids

Doisynolic acids, D-ring seco-steroids derived from alkaline fusion of estrones, are hormonal curiosities: Their binding affinity for the estrogen receptor is low (ca. 1-2% that of estradiol), but their in vivo potency is high and they have a long duration of action. To study the in vivo behavior of the doisynolic acids, we prepared fluorine-substituted analogs of both trans-doisynolic acid (with the natural 14 alpha-hydrogen configuration, trans-FDA) and the more active cis-doisynolic acid (with the unnatural 14 beta-hydrogen configuration, cis-FDA) from estrone and 14 beta-estrone, respectively. Modification of the D-ring haloform cleavage approach of Meyers allowed us to introduce fluorine (or fluorine-18) on the carbon atom derived from C-16 in the estrones. Fluorine substitution had little effect on the estrogen receptor binding affinity of the doisynolic acids. Tissue distribution of the fluorodoisynolic acids (trans-[18F]FDA and cis-[18F]FDA) was unusual and very different from that of typical, high-affinity ligands for the estrogen receptor. At 1-3 h in immature female rats, trans-[18F]FDA shows low and rather nonselective uptake in the principal estrogen target tissue (uterus) and slow clearance. By contrast, cis-[18F]FDA shows high uptake in nearly all tissues, with significant uterine uptake that continues to increase over the 1-6-h period. The uterine uptake of this isomer was blocked at the later times by a sufficiently high dose of unlabeled cis-FDA. After administration of the trans-[18F]FDA, a more polar metabolite slowly accumulates in the blood. The cis-[18F]FDA, however, showed no apparent metabolism, with 84% of the blood activity at 5 h assigned as the unmetabolized radioligand. After 5 h, only limited clearance from blood, liver, and kidneys has occurred. No metabolite from this isomer accumulates in the uterus. Although fluorodoisynolic acids will not be useful breast-tumor imaging agents, their behavior was found to be interesting as it deviates from that of other F-18 estrogens. Further long-term studies of cis-doisynolic acid, labeled with tritium, may be needed to explicate fully its unusual distribution properties and high in vivo activity.