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The total synthesis of (+)-03219A, a rare Δ8,9-pregnene isolated from the marine-derived Streptomyces sp. SCSIO 03219, is described that is based on a series of transformations that enable progression from epichlorohydrin to an ent-estrane, then conversion to a nat-androstane, and finally establishment of the natural product target. Key to the success of these studies was implementation of two rearrangement processes to formally invert the quaternary center at C13 and establish the C10 quaternary center.

To prepare new type of estrane hybrid molecules, we chose 3-methoxy- and 3-benzyloxy-17β,16β-epoxymethylene-estra-1,3,5(10)-trienes as starting materials (2 and 5). These steroid oxetanes were transformed with ethylene glycol in the presence of BF3.OEt2 into 3-methoxy- and 3-benzyloxy-16β-(2′-oxa-4′-hydroxy)butyl-17β-hydroxy-estra-1,3,5(10)-trien-17β-ols (3a and 6a). Iodination of the terminal hydroxy group afforded iodo derivatives 3b and 6b, which underwent one-pot 3-O-alkylation with unprotected ascorbic acid to yield 3c and 6c. The same process with salicylic acid led to 2-O-alkylated salicylic acid derivatives 3d and 6d. Iodo derivatives 3b and 6b underwent nucleophilic exchange reaction with NaN3 furnishing the corresponding azido compounds 3e and 6e. These compounds were subjected to azide–alkyne CuAAC reactions with phenylacetylene and their p-substituted derivatives to form 1,4-substituted triazoles 3f-h and 6f-h. The reduction of 3e and 6e with hydrazine hydrate in the presence of Raney Ni provided the corresponding amino derivatives 3i and 6i. These compounds were reacted further with varied substituted benzoic acids to deliver terminal benzamido derivatives 3j-m and 6j-m. We determined the in vitro antiproliferative activities of compounds 2, 5, 3a-m and 6a-m by means of MTT assays on a panel of human adherent cancer cell lines A2780, MCF-7, MB-231 and SiHa.

In this study, eighteen novel steroidal-furoxan derivatives with 3-glycosyl or 3-methoxy moiety (12a-c, 13a-c, 17a-c, 26a-c, 27a-c and 28a-c) were synthesized and their anti-proliferative activity was evaluated against eight drug-sensitive and three drug-resistant cancer cell lines HeLa, A2780, LNCaP, PC-3, MDA-MB-231, MCF-7, SW480, A549, MCF-7/ADR, A2780/CDDP and A2780/T. Most of them displayed significant anti-cancer potency in vitro with IC50 values at the nanomole level. Among them, 3-methoxy steroidal-furoxan hybrids expressed much better activity than that of 3-glycosyl substitute ones, while estrane and 5α-H-androstane scaffold were slightly more favorable to the improvement of anti-proliferative activity. Especially, compounds 27c and 28b showed the strongest cytotoxicity with IC50 values of 0.0007–0.034 and 0.0011–0.008 µM, respectively in five drug-sensitive cancer cell lines. Furthermore, 3-glycoconjugates 13a, 13c, 17b and 3-methoxy compounds 27a, 27c, 28b displayed lower toxicity in nontumorigenesis cells HOSEC and expressed a good selectivity against malignant cells in vitro. Preliminary study of pharmacology showed that the introduction of glucose at 3-position in steroidal core seems unable to use glucose transporters to improve the selectivity against proliferation of malignant cells, while the NO-releasing capacity might explain the potent anti-neoplastic activity of these compounds. And compound 28b could induce the apoptosis and hardly affected the cell cycle of A2780. Then, the further study of these steroidal-furoxan hybrids merits to explore and develop a desirable anti-cancer candidate.

17β-Hydroxysteroid dehydrogenase type 1 (17β-HSD1) is a promising therapeutic target known to play a pivotal role in the progression of estrogen-dependent diseases such as breast cancer, and endometriosis. This enzyme is responsible for the last step in the biosynthesis of the most potent estrogen, estradiol (E2) and its inhibition would prevent the growth of estrogen-sensitive tumors. Based on molecular modeling with docking experiments, we identified two promising C3-oxiranyl/oxiranylmethyl-estrane derivatives that would bind competitively and irreversibly in the catalytic site of 17β-HSD1. They have been synthesized in a short and efficient route and their inhibitory activities over 17β-HSD1 have been assessed by an enzymatic assay. Compound 15, with an oxiranylmethyl group at position C3, was more likely to bind the catalytic site and showed an interesting, but weak, inhibitory activity with an IC50 value of 1.3 µM (for the reduction of estrone into E2 in T-47D cells). Compound 11, with an oxiranyl at position C3, produced a lower inhibition rate, and the IC50 value cannot be determined. When tested in estrogen-sensitive T-47D cells, both compounds were also slightly estrogenic, although much less than the estrogenic hormone E2.

The interest in the introduction of the oxime group in molecules aiming to improve their biological effects is increasing. This work aimed to develop new steroidal oximes of the estrane series with potential antitumor interest. For this, several oximes were synthesized by reaction of hydroxylamine with the 17-ketone of estrone derivatives. Then, their cytotoxicity was evaluated in six cell lines. An estrogenicity assay, a cell cycle distribution analysis and a fluorescence microscopy study with Hoechst 3358 staining were performed with the most promising compound. In addition, molecular docking studies against estrogen receptor α, steroid sulfatase, 17β-hydroxysteroid dehydrogenase type 1 and β-tubulin were also accomplished. The 2-nitroestrone oxime showed higher cytotoxicity than the parent compound on MCF-7 cancer cells. Furthermore, the oximes bearing halogen groups in A-ring evidenced selectivity for HepaRG cells. Remarkably, the Δ9,11-estrone oxime was the most cytotoxic and arrested LNCaP cells in the G2/M phase. Fluorescence microscopy studies showed the presence of condensed DNA typical of prophase and condensed and fragmented nuclei characteristic of apoptosis. However, this oxime promoted the proliferation of T47-D cells. Interestingly, molecular docking studies estimated a strong interaction between Δ9,11-estrone oxime and estrogen receptor α and β-tubulin, which may account for the described effects.

A simple and efficient synthesis of novel estrone 16α,17α-oxazoline derivatives substituted at the D ring (compounds 6a-g) is described. The reduction of 16α-azido-3-methoxyestra-1,3,5-trien-17-one (1) in methanol in the presence of CeCl3 under the condition of the Luche reaction produced two epimeric azido alcohol (16α-azido-17α-hydroxy and 16α-azido-17β-hydroxy) derivatives of estra-1,3,5(10)-triene-3-methyl ether (compounds 2 and 3) in a yield of 90% and 7.6%. The reaction of the sterically unhindered 16α-azido-17α-hydroxy-estra-1,3,5(10)-triene-3-methyl ether (2) with a range of benzaldehydes under the condition of the Schmidt rearrangement yielded d -ring substituted estrone 16α,17α-oxazoline derivatives 6a-g. The in vitro antiproliferative activities of compounds 1, 2, 3, 6a-g were also determined by means of MTT assays on a panel of human cancer cell lines HeLa, SiHa, C-33 A, A2780, MCF-7, MDA-MB-231 and T47D.

Organic anion-transporting polypeptide 2B1 (OATP2B1) is a multispecific membrane transporter mediating the cellular uptake of various exo- and endobiotics, including drugs and steroid hormones. Increased uptake of steroid hormones by OATP2B1 may increase tumor proliferation. Therefore, understanding OATP2B1′s substrate/inhibitor recognition and inhibition of its function, e.g., in hormone-dependent tumors, would be highly desirable. To identify the crucial structural features that correlate with OATP2B1 inhibition, here we designed modifications at four positions of the estrane skeleton. 13α- or 13β-estrone phosphonates modified at ring A or ring D were synthesized. Hirao and Cu(I)-catalyzed azide–alkyne click reactions served in the syntheses as key steps. 13β-Derivatives displayed outstanding OATP2B1 inhibitory action with IC50 values in the nanomolar range (41–87 nM). A BODIPY-13α-estrone conjugate was additionally synthesized, modified at C-3-O of the steroid, containing a four-carbon linker between the triazole moiety and the BODIPY core. The fluorescent conjugate displayed efficient, submicromolar OATP2B1 inhibitory potency. The newly identified inhibitors and the structure–activity relationships specified here promote our understanding about drug recognition of OATP2B1.

Steroid sulfatase (STS) is an important enzyme regulating the conversion of sulfated steroids into their active hydroxylated forms. Notably, the inhibition of STS has been shown to decrease the levels of active estrogens and was translated into clinical trials for the treatment of breast cancer. Based on quantitative structure-activity relationship (QSAR) and molecular modeling studies, we herein report the design of fluorescent inhibitors of STS by adding a dansyl group on an estrane scaffold. Synthesis of 17α-dansylaminomethyl-estradiol (7) and its sulfamoylated analog 8 were achieved from estrone in 5 and 6 steps, respectively. Inhibition assays on HEK-293 cells expressing exogenous STS revealed a high level of inhibition for compound 7 (IC50 = 69 nM), a value close to the QSAR model prediction (IC50 = 46 nM). As an irreversible inhibitor, sulfamate 8 led to an even more potent inhibition in the low nanomolar value (IC50 = 2.1 nM). In addition, we show that the potent STS inhibitor 8 can be employed as an optical imaging tool to investigate intracellular enzyme sub-localization as well as inhibitory behavior. As a result, confocal microscopy analysis confirmed good penetration of the STS fluorescent inhibitor 8 in cells and its localization in the endoplasmic reticulum where STS is localized.

The aminosteroid (AM) RM-581 is built around a mestranol backbone and has recently emerged as this family’s lead candidate, showing in vitro and in vivo potency over different types of cancer, including high fatality pancreatic cancer. To extend the structure-activity relationships (SAR) to other estrane analogs, we synthesized a focused series of RM-581 derivatives at position C3 or C2 of its steroidal core. These new AM derivatives were first tested on a large selection of prostate, breast, pancreatic and ovarian cancer cell lines. The impact of these modifications on metabolic stability (human liver microsomes) was also measured. A SAR study revealed a fine regulation of anticancer activity related to the nature of the substituent. Indeed, the addition of potential prodrug groups like acetate, sulfamate or phosphate (compounds 8, 9 and 10) at C3 of the phenolic counterpart provided better antiproliferative activities than RM-581 in breast and pancreatic cancer cell types while maintaining activity in other cancer cell lines. Also, the phosphate group was highly beneficial on water solubility. However, the bulkier carbamate prodrugs 6 (N,N-dimethyl) and 7 (N,N-diethyl) were less active. Otherwise, carbon homologation (CH2) at C2 (compound 33) was beneficial to metabolic stability and, in the meantime, this AM conserved the same anticancer activity as RM-581. However, the replacement of the hydroxy or methoxy at C3 by a hydrogen or an acetyl (compound 17 or 21b) was detrimental for anticancer activity, pointing to a crucial molecular interaction of the aromatic oxygen atom at this position. Overall, this work provided a better knowledge of the structural requirements to maintain RM-581’s anticancer activity, and also identified minor structural modifications to increase both metabolic stability and water solubility, three important parameters of pharmacological development.

Fluorination of 13-epimeric estrones and their 17-deoxy counterparts was performed with Selectfluor as the reagent. In acetonitrile or trifluoroacetic acid (TFA), 10&beta, fluoroestra-1,4-dien-3-ones were formed exclusively. Mechanistic investigations suggest that fluorinations occurred via SET in acetonitrile, but another mechanism was operative in TFA. Simultaneous application of N-chlorosuccinimide (NCS) and Selectfluor in TFA led to a 1.3:1 mixture of 10&beta, fluoroestra-1,4-dien-3-one and 10&beta, chloroestra-1,4-dien-3-one as the main products. The potential inhibitory action of the 10-fluoro- or 10-chloroestra-1,4-dien-3-one products on human aromatase was investigated via in vitro radiosubstrate incubation. The classical estrane conformation with trans ring anellations and a 13&beta, methyl group seems to be crucial for the inhibition of the enzyme, while test compounds bearing the 13&beta, methyl group exclusively displayed potent inhibitory action with submicromolar or micromolar IC50 values. Concerning molecular level explanation of biological activity or inactivity, computational simulations were performed. Docking studies reinforced that besides the well-known Met374 H-bond connection, the stereocenter in the 13 position has an important role in the binding affinity. The configuration inversion at C-13 results in weaker binding of 13&alpha, estrone derivatives to the aromatase enzyme.

Unique derivatives of androstene and estrane series containing N-sulfonylimidate pendants were prepared from 17α-ethynyl steroids via Cu-catalyzed azide–alkyne cycloaddition to tosyl azide in the presence of alcohols. The synthesized compounds were screened for cytotoxicity against human breast cancer cell lines and ERα agonist activity. The hit compound 3,17β-dimethoxy-17α-[iso-propyl-2′-N-tosylacetimidate]estra-1,3,5(10)-triene (4n) had no ERα-mediated hormonal activity and was found to exhibit potent cytotoxic effect in an ERα-positive breast cancer cell line. N-Sulfonylimidate 4n displayed high antiproliferative potency against triple-negative MDA-MB-231 breast cancer cells, while it was non-toxic towards normal mammary epithelial cells. Compound 4n was found to alter activity of various signaling pathways (NF-κB, Slug, cyclin D1, ERK) supporting the growth and invasiveness of tumor cells.

Inhibition of cytochrome P450 (CYP) 1B1 is a promising therapeutic strategy, as such an inhibitor could modulate the bioactivation of procarcinogens while reducing drug resistance. Based on docking studies, the synthesis of 12 estra-1,3,5(10)-triene derivatives containing a pyridin-3-/4-yl moiety at position C2, C3, or C4 was performed, and we measured their inhibitory activity on CYP1B1 using the ethoxyresorufin-O-deethylase (EROD) assay. The position of the nitrogen atom in the aromatic ring has little influence on their inhibition potency, but compounds with a pyridinyl at C2 of the steroid nucleus are more potent CYP1B1 inhibitors than those with a pyridinyl at C3 or C4. Estradiol derivatives (OH at C17β) are also 10-fold more potent inhibitors than estrone derivatives (carbonyl at C17). Thus, 2-(pyridin-3-yl)-estradiol (4a) is the best CYP1B1 inhibitor (IC50 = 0.011 μM) from this series of compounds, and the best steroid inhibitor reported until now. It is also 7.5-fold more potent than the well-know...

Anticancer structure–activity relationship studies on aminosteroid (5α-androstane) derivatives have emerged with a promising lead candidate: RM-133 (2β-[1-(quinoline-2-carbonyl)pyrrolidine-2-carbonyl]-N-piperazine-5α-androstane-3α,17β-diol), which possesses high in vitro and in vivo activities against several cancer cells, and selectivity over normal cells. However, the relatively weak metabolic stability of RM-133 has been a drawback to its progression toward clinical trials. We investigated the replacement of the androstane backbone by a more stable mestranol moiety. The resulting compound, called RM-581 ({4-[17α-ethynyl-17β-hydroxy-3-methoxyestra-1,3,5(10)-trien-2-yl]piperazin-1-yl}[(2S)-1-(quinolin-2-ylcarbonyl)pyrrolidin-2-yl]methanone), was synthesized efficiently in only five steps from commercially available estrone. In comparison with RM-133, RM-581 was found to be twice as metabolically stable, retains potent cytotoxic activity in breast cancer MCF-7 cell culture, and fully blocks tumor growth in a mouse xenograft model of breast cancer. Advantageously, the selectivity over normal cells has been increased with this estrane version of RM-133. In fact, RM-581 showed a better selectivity index (15.3 vs. 3.0) for breast cancer MCF-7 cells over normal breast MCF-10A cells, and was found to be nontoxic toward primary human kidney proximal tubule cells at doses reaching 50 μm.

Inhibition of cytochrome P450 1B1 (CYP1B1) represents a promising therapeutic strategy, because it would enable action at three different levels: (1) by inhibiting the formation of mutagenic 4-hydroxy-estradiol, (2) by inhibiting the bioactivation of procarcinogens, and (3) by reducing drug-resistance. Surprisingly, few steroids were reported as inhibitors of CYP1B1. From a screening performed with 90 steroid derivatives, we identified thioestrone (B19) as an inhibitor (IC50=3.4μM) of CYP1B1. Molecular modeling studies showed that the 3-SH group of B19 is closer (3.36A) to the iron atom of the heme system than the 3-OH group of enzyme substrates estrone and estradiol (4.26A and 3.58A, respectively). B19 also produced a better docking GOLD score that correlated with the inhibitory results obtained. The estrane derivative B19 represents an interesting lead compound that can be easily modified to extend the structure-activity relationship study and to provide a next generation of more powerful CYP1B1 inhibitors.

An elegant approach to unknown steroidal imidazo[1,2- a ]pyridine hybrids is disclosed. Unique derivatives of androstene and estrane series containing imidazo[1,2- a ]pyridine motifs were prepared from 17-ethynyl steroids in good yields via copper-catalyzed cascade aminomethylation/cycloisomerization with imines. The synthesized compounds were screened for cytotoxicity against human breast (MCF-7, MDA-MB-231, HBL-100, MDA-MB-453) and prostate (LNCaP-LN3, PC-3, DU 145) cancer cell lines. The majority of tested compounds showed activities at μM level in breast cancer cells. The hormone-responsive breast cancer cells MCF-7 were more sensitive to novel compounds than ERα-negative cells; in particular, compounds 6a , b exhibited promising cytotoxicity against this cell line with the IC 50 values in the range of 3–4 μM. Furthermore, compound 4a showed remarkable effects as a selective ERα receptor modulator.

3,17-Dioxo-Δ4-androsten-19-al (II) is a suitable starting material for the preparation of estrane derivatives. Autoxidation gives the corresponding 10β-hydroperoxide III, which can be converted to estrone (V) by reduction and aromatization. Treatment with alkaline reagents under various conditions can produce 3-oxo-Δ4- (VI), 3-oxo-Δ5(10) - (VII) and 2-hydroxymethylene-3-oxo-Δ5(10) - estrene (VIII) derivatives.

An intramolecular cyclization of 17β‐acetoxy‐3‐methoxy‐9,11‐seco‐1,3,5(10)‐estratriene‐11‐oic acid under different Friedel–Crafts reaction conditions is described.

Organocerium compounds are the reagents of choice for the introduction of side chains onto estrone methyl ether. A 19-norcholestane derivative was prepared as a model for a geochemical biomarker by subsequent dehydration and C-C double-bond hydrogenation.

The acylation of an excess of racemic spirolactone 1 (6,9-divinyl-1-oxaspiro[4.4]nonan-2-one) enolate by protected methyl (S)-lactate or (–)-bornyl carbonate occurs with a kinetic resolution. The resulting lactones were alkylated with 1-iodobenzocyclobutenes to afford compounds that serve as precursors to nonracemic steroids such as 11α-alkyloxycarbonyl-11β,13β-(γ-carbolactone)-17β-vinylgonatri-1,3,5(10)-enes. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

The estrane analogue of OSW-1, a potent antitumor natural saponin, was efficiently synthesized from estrone in 12 steps. The cytostatic activity of the compound against several human malignant tumor cells was examined and compared to those of the natural OSW-1 and cisplatin, the results suggesting that the modification of the steroidal component could be an effective approach in the search for new candidates of anticancer drugs. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Various steroidal oxime ether derivatives in androstene and estrane series have been synthesized and evaluated for the antineoplastic activity at National Cancer Institute, Bethesda, Maryland, USA. O-alkylation of the oximes by various alkylaminoethyl halides gave the oxime ether derivatives. The 17alpha-ethynylandrostene derivatives 29 (DPJ-684), 30 (DPJ-685), 31 (DPJ-686) and estrane derivatives 35 (DPJ-531) and 36 (DPJ-532) were among the small percentage of compounds, which have been screened by NCI for in vivo hollow fiber assay by virtue of their activity against one or more human tumour cell lines in 60 cell line in vitro prescreen. The preliminary in vivo reports of hollow fiber assays have been referred to the Biological Evaluation Committee for Cancer Drugs for considering these compounds for further detailed in vivo testing.

Four new estrone derivatives were isolated after treatment of estrone 3-methyl ether (3-methoxyestra-1,3,5(10)-trien-17-one (3) with tert-butyl hydroperoxide and cobalt acetate. Three of the four steroidal compounds − the 9α-(tert-butylperoxy)-6-one 4, the 9α-hydroxy-6-one 5, and the 9β-hydroxy-6-one 7 − originated from oxidation at the 6- and 9-positions. In contrast, oxidation of 3 to a 9β-(tert-butylperoxy) compound afforded the 8-hydroxy-9-cyclodecanone derivative 6 through a molecular rearrangement involving the cleavage of the 8−9 bond. The structures of the compounds were secured by spectroscopic evidence including COSY, HSQC, and NOESY experiments combined with X-ray crystallographic analysis and molecular modeling studies. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Two series of compounds, benzyl alkylated at position 17alpha and 20 of androstane and pregnane, respectively, were synthesised and tested for steroid sulphatase inhibition. We compared the ability of the compounds to inhibit steroid sulphatase obtained from two different sources (homogenates of transfected HEK-293 cells and Jeg-3 cells) and with two types of substrate (DHEAS or E(1)S). The inhibitory activity of 17alpha-benzyl-5alpha-androstane-3beta,17beta-diol (7), 17alpha-benzyl-5-androstene-3beta,17beta-diol (9), 17alpha-benzyl-4,17beta-dihydroxy-4-androsten-3-one (15) and 20-benzyl-5-pregnene-3beta,20alpha-diol (16) has proven to be superior to that of danazol, the first steroid sulphatase inhibitor to be reported, but still lower than that of the potent inhibitor estrone-3-O-sulphamate. The inhibitory activity of compound 7 was as potent as that of its previously reported estrane analogue, 17alpha-benzyl estradiol. Benzyl alkylated compounds with no OH group on the A-ring (with a 4-OCH(3), 4-Cl, or 4-H and their precursor epoxides), as well as a series of basic steroids without a benzyl group (ADT, epi-ADT, 3alpha-diol, 3beta-diol, DHEA, Delta(5)-diol, DHT, T, Preg and Prog), did not show steroid sulphatase inhibition. We have thus demonstrated that the steroid sulphatase inhibitory effect of a benzyl group, previously observed for an estrane nucleus, can be extended to certain androstane and pregnane nuclei bearing a 3beta-OH or a 4-OH group. Inhibitors 7, 9, 15 and 16 did not induce any proliferative effect on androgen-sensitive Shionogi cells. However, when tested on oestrogen-sensitive ZR-75-1 cells, a proliferative effect was observed for 7 and 9, but not for 15 and 16.

Reaction of (η 6 -p-chlorotoluene)(η 5 -cyclopentadienyliron)(II) hexafluorophosphate with the phenolic hydroxy group of estrane steroids, under mild conditions, leads to the formation of 3-O-p-tolyle thers of steroids, with an iron(Cp) marker. Employing this reaction, estrone, estradiol and 17-α-ethynylestradiol have been marked in high yield. The utility of such marked steroids in metalloimmunoassay has been examined. Steroids marked in such a way show no measurable affinity for the estradiol receptor. The 3-O-p-tolyestrone complex is stable at room temperature for 24 h, in water solutions of buffers at pH 2.0 and 7.41, as well as in a THF solution in the presence of pyrrolidine. The marker fragment may be removed at room temperature upon the action of pyrrolidine in a 1:1 water-THF solution or potassium hydroxide in water for 24 h with the efficient recovery of steroid. Treatment of marked estrone with an excess of potassium t-butoxide leads to demetallation and the formation of 3-O-p-tolylestrone. Attempts to mark estrone and testosterone via the carbonyl group or estradiol and cholesterol via the secondary hydroxyl group, under mild conditions, have been unsuccesful.

A concept of first choice for the synthesis of the title compounds had been proposed by Dane in the late 1930s. It was soon turned down, because the opening move–a chirogenic Diels-Alder reaction – did not work. With Lewis acids as mediators, however, a successful start has been achieved now. With Ti complexes of chelating ligands (Seebach's TADDOLs (= α,α,α′,α′-tetraaryl-1,3-dioxolane-4,5-dimethanols)), enantioselective formation of the desired adducts does occur. Efficient total syntheses of 2 and 3a have been accomplished.

The synthesis of 11α-methyl-11β-(arylethynyl) substituted 19-norsteroids of 13, 14, and 15 is described. The preparation of these compounds opens for the first time an approach to 11-disubstituted antiprogestins.

A spirolactone 2 , obtained in two steps from 1,3-butadiene (ca. 50 %), was methoxycarbonylated (LiHMDS / dimethylcarbonate) and alkylated with iodo

o-Carboranylmethyl ethers of steroids were synthesized by insertion of steroidal 2-propynyloxy derivatives into 6,9-bis(acetonitrile)decaborane (12). This reaction afforded compounds with estrane and androstane skeleton, potentionally useful in boron neutron capture therapy of hormone-sensitive forms of cancer: 17β-o-carboranylmethyl ether of estradiol IXb (yield 14%) and 3β- and 17β-carboranylmethyl ethers of androstenediol Vb and VIIb (yield 12% and 13%, respectively). Jones oxidation afforded carboranyl derivative of androsten-17-one VIb in 75% yield. As shown by a study of insertion of 3β-(2-propynyloxy)cholest-5-ene (IVa), the low yields of the insertion reaction cannot be increased by change in the reaction conditions. The relative binding affinity of compound IXb to estrogen receptor from rat uterine and human breast tumor cytosol was 3.0 and 0.29% respectively, of that of estradiol.

Incubation of estrone ( 1a ) with Streptomyces roseochromogenes ATCC 13400 yielded a mixture of 3,16α-dihydroxyestra-1,3,5(10)-trien-17-one ( 3a ) and 3,17β-dihydroxyestra-1,3,5(10)-trien-16-one ( 4a ). Transformation of 3-methoxyestra-l,3,5(10)-trien-17-one ( 1b ), 3-hydroxyestra-1,3,5(10),9(11)-tetraen-17 -one ( 2a ), and 3-methoxyestra-1,3,5(10),9(11)-tetraen-17-one ( 2b ) with the same microorganism gave the corresponding mixtures of 16α-hydroxy-17-ketones and 17β-hydroxy-16-ketones ( 3b and 4b , 6a and 7a , 6b and 7b , respectively). In addition, in these three last experiments, the 16β-17β-dihydroxy derivatives 5b , 8a , and 8b , respectively, were also isolated. The complete assignments of the 3 C nuclear magnetic resonance spectra of these compounds are given. (Steroids 55 :390–394, 1990)

tert-Butyl hydroperoxide catalyzed by (5,10,15,20-tetramesitylporphyrinate) osmium(II) carbonyl [Os(TMP)CO] complex was found to be a highly efficient versatile oxidant for C-H carbons in steroid substrates. When reacted with representative steroids with an estrane, pregnane, 5beta-cholane, or 5alpha-cholestane structure, regioselective oxyfunctionalization and/or oxidative degradation occurred to give a variety of novel and uncommon derivatives in one step.

18-Nor-16-azaestrane derivatives with 8β, 13β, and 14β orientation were isolated from Diels-Alder reactions between maleimides or citraconimide and 1-(1-siloxyvinyl)naphthalene derivatives. (8RS)-13,14,16-Triazaestrane derivatives were synthesized from 1,2,4-triazolin-3,5-diones. The parent 11-oxo derivatives were obtained by desilylation, and they were transformed into 11-hydroxyimino derivatives. 3-Hydroxy derivatives, finally were synthesized by cleavage of the 3-methoxy group with BBr3. During these transformations the stereochemistry of the steroidal skeleton was not changed. The stereochemistry of these “unnatural” steroids was elucidated by spectroscopic methods, and compared with results from calculations, and with the configuration of natural estrane derivatives. Finally, an improved method for the synthesis of the starting material, 6-methoxy-1-[(1-trialkylsiloxy)-vinyl]-3,4-dihydronaphthalene was developed.

Oxidation of 4-nitro-17beta-estradiol (1) with the peroxidase/H(2)O(2) system gave the symmetric C(2)-linked dimer (3) through phenoxy radical coupling. Similar oxidation of 2-nitro-17beta-estradiol (2), in which the nitro group is coplanar with the aromatic ring, yielded 9alpha- and 9beta-hydroxy-2-nitro-17beta-estradiol (4a,b), (17beta)-2-nitroestra-1(10),2,4,9(11)-tetraene-3,17-diol (5), and (12alpha,17beta)-2-nitroestra-1(10),2,4,9(11)-tetraene-3,12,17-triol (6). With higher concentrations of H(2)O(2), the novel secoestra-1(10),2,4-trien-9-one derivative 7 was obtained from 2. Theoretical calculations suggested that the peculiar behavior of 2 may be due to the generation of a relatively stable radical intermediate at C(9), which would then be converted to the reactive quinone methide 8. The chemistry described in this paper appears to be an intriguing example of control of the site of substitution over evolution of phenoxy radicals, and opens new vistas toward selective oxyfunctionalization of the estrane skeleton.

D-Homo derivatives in the androstane and estrane series, 12-19, were synthesized by a fragmentation-cyclization reaction of 16-oximino-17-hydroxy-17-substituted derivatives 3-9, or by cyclization of the corresponding D-seco derivatives 20-26. The structures were confirmed by X-ray analysis of compounds 12 and 16. Preliminary assessment of inhibitory effects of D-homo derivatives from androstane series towards aromatase, 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), 17 alpha-hydroxylase/C17-20 lyase (P450c17) and 17 beta-HSD indicated much lower inhibitory potential compared to previously tested activity of another type of D-modified steroids, namely D-seco derivatives. Also, assessment of potential antiestrogenic activity of derivatives from estrane series showed absence of such an activity.

5α-Estrane-3β,17α-diol is the major metabolite of nandrolone in horse urine. The presence of 5α-estrane-3β,17α-diol in female and gelding urines is prohibited by Racing Rules and its natural presence in male urine led regulation authorities to establish a concentration threshold of 45 ng/mL. This paper describes a rapid, simple and stereoselective synthesis of 5α-estrane-3β,17α-diol, providing horseracing laboratories with an essential reference material for their antidoping performance.

A successful approach in the synthesis of 3 beta-acetoxy-17a-selena-D-homo-1,3,5(10)-estratrien-17 -one (5), 3 beta-acetoxy-17a tellura-D-homo-1,3,5(10)-estratrien-17-one (6), and 3 beta-acetoxy-17a-thia-D-homo-1,3,5(10)-estratrien-17-one (7) was achieved from 3 beta-acetoxy-1,3,5(10)-estratrien-17-one (1). The Baeyer-Villiger reaction of 3 beta-acetoxy-1,3,5(10)-estratrien-17-one (1) with perbenzoic acid afforded 3 beta-acetoxy-17a-oxa-D-homo-1,3,5(10)-estratrien-17-one (2), which on reaction with hydrobromic acid gave 3 beta-acetoxy-seco-13-bromo-1,3,5(10)-estratrien-16-oic acid (3). Treatment of bromo acid (3) with thionyl chloride gave 3 beta-acetoxy-seco-13-bromo-1,3,5(10)-estratrien-17 acid chloride (4), whose reaction with Se and Te in the presence of sodium borohydride gave the desired products 5 and 6. Reaction of 3 beta-acetoxy-seco-13-bromo-1,3,5(10)-estratrien-17 acid chloride (4) with sodium sulfide gave the thia lactone derivative (7).

By a novel “one pot” fragmentation-cyclization reaction 17β-hydroxy-17α-substituted-16-oximino derivatives in the androstane and estrane series were converted to a new type of D-homo derivative.

By the action of acidic titanium trichloride upon 16-oximino-17α-benzyl-17β-hydroxy derivatives in the androstane and estrane series the 16-oxo-17β-benzyl-17α-hydroxy derivatives 6 and 7 with inversed configuration at C 17 were obtained. A mechanism for this novel rearrangement is proposed.

An efficient new synthesis of 17-azasteroids in the estrane and androstane series was developed from readily available 16,17-seco 17-carboxylic acid precursors by means of a diphenylphosphoryl azide-mediated Curtius rearrangement as the key step. Several novel N-chloro-17-aza- and N-chloro-17a-aza-17a-homosteroids were prepared from the corresponding lactams with N-chlorosuccinimide

Novel 15-oxa-D-homosteroids related to pregnane and estrane derivatives have been prepared.

Racemic 14 beta-hydroxy-3-methoxy-8 alpha,9 alpha-1,3,5(10)-estratriene-17-one (I), obtained by total synthesis, was converted into a derivative with alkoxycarbonyl-ethylenic side chain, rac-(20E)-21-methoxycarbonyl-19-nor-8 alpha,9 alpha-pregna- 1,3,5(10),20-tetraene-3,14 beta-diol 3-methyl ether (XII) using two Wittig reactions. Analogous derivatives of 5 alpha-androstane were prepared as synthetic models. In the estrane series the stereochemistry of attachement of the side chain in position 17, biological activity of some compounds, and their chromatographic properties were investigated.

Die Kristallstrukturen von zwei 11β-(4-Fluorphenyl)-substituierten Steroiden mit unterschiedlicher Konfiguration an C-13 wurden bestimmt. Auf der Basis der rontgenanalytischen Daten wurde der Versuch unternommen, Ahnlichkeiten und Unterschiede im biologischen Verhalten beim Ubergang von der Ostran-Reihe zur 13α-Gonan-Serie zu deuten. X-ray Analyses and Structure-Activity Relations of Antiprogestins The crystal structures of two 11α-(4-fluorophenyl)-substituted steroids with adverse configurations at position C-13 were determined. Based on the X-ray data, an attempt was made to interpret similarities and diversities in biological behaviour between the estrane and the 13α-gonane series.

New, potential aldosterone blocking 17-spiro-oxazolidinone derivatives with androstane, estrane and 13β-ethyl-gonane ring system were synthesized. 17S-Spiro-oxiranes were used as starting compounds and the oxazolidinone ring was built up in different ways. All compounds but one were devoid of considerable endocrine activities. 3-Oxo-13β-ethyl-gona- -4,9(10), 11-triene-17S-spiro-5′-(2′-oxo-3′-methyl)oxazol-idine shows significant antiandrogen activity on s.c., but none on p.o. administration.

C-Homosteroide der Androstan-, Pregnan- und Ostran-Reihe lassen sich partialsynthetisch aus Hecogenin (2) herstellen. Die C-Homoostratriene zeigen pharmakologische Wirksamkeit im Tierversuch. C-Homosteroids, II Partial Synthesis of C-Homosteroids C-Homosteroids in the androstane, pregnane, and estrane series can be prepared from hecogenine (2) following partial synthetic methods. The C-homoestratrienes exhibit pharmacological activity in animal experiments.

Inhibition of 5alpha-reduction of testosterone by an anti-androgen TSAA-291 (16beta-ethyl-17beta-hydroxy-4-estren-3-one) was studied in rat ventral prostates and the metabolic conversion of 3H-TSAA-291 was examined both in vitro and in vivo. In the in vitro experiment using nuclear 5alpha-reductase of the prostate, 5alpha-dihydrostestosterone formation from 3H-testosterone was inhibited in a competitive manner by the anti-androgen. In the in vitro experiment using 3H-TSAA-291, 5alpha-reduction of the anti-androgen occurred. One, 2 and 4 hr after an intravenous administration of 140 muCi/rat of 3H-TSAA-291 to castrated rats, the unchanged TSAA-291 accumulated in higher amounts in the ventral prostate than in the plasma, skeletal muscle and levator ani muscle, thereby indicating the selective uptake of the anti-androgen by the androgen target organ. No appreciable amounts of the 5alpha-reduced metabolite of TSAA-291 were detected in the prostate, thus suggesting that TSAA-291 itself may be responsible for the anti-androgenic properties. The inhibitory potency of the 5alpha-reductase activity of several other 16beta-substituted androstane and estrane analogues was also examined.

A series of 7alpha- and 7beta- alkyl derivatives of steroidal 4-en- and 5-en-3-ones were prepared by 1,6-conjugate addition of organocopper reagents to various steroidal 4,6-dien-3-ones of the androstane, estrane and gonane series. Biological study of these and related compounds revealed that 17beta-hydroxy-7alpha-methyl-5-androsten-3-one (2), 17beta-hydroxy-7alpha-methyl-5-estren-3-one acetate and 17beta-hydroxy-7alpha-methyl-4-estren-3-one acetate had significant anti-implantational and antidecidual activities. The contragestative effects were associated with the latter anti-hormonal properties, and not with the androgenicity of these compounds.

Structural modifications of testosterone and 19-nortestosterone have led to the synthesis of over 60 androstane and estrane derivatives whose sensory evaluation has allowed molecular parameters to be established for release of a ‘steroid-type’ scent. Odor perception with O-containing compounds in both classes has been found to be regioselective1. Osmophoric groups at C(3) were found to be the most active and specific. Functionality at C(2) is accompanied to a large extent by anosmic defects, and O-containing substituents at C(1) and C(4) appear to affect the receptor membrane in exceptional cases. A further characteristic of the ‘steroid-type’ scent is diastereoselectivity. The odor intensity of axial 2- and 3-hydroxysteroids is far greater than that of the equatorial epimers, and epimeric hydroxy-groups in the 1-, 4-, and 5-positions lead to almost complete absence of odor. In addition, only steroids with ‘normal’ ring junctions and configuration were found to be odorants, whereas compounds with cis-junctions between rings A and B, or C and D, were found to be practically inactive, Steroids therefore folow the ‘triaxial rule of odor sensation’. The most remarkable feature of our findings with steroid odorants is enantioselectivity1 . Whereas with C 19 -steroids of the ‘natural’ enantiomeric series the perception threshold is extremely low (