Synthesis and biological evaluation of some 17-picolyl and 17-picolinylidene androst-5-ene derivatives

Starting from dehydroepiandrosterone (1) 17-picolyl (2), 17-picolinylidene (7), 17-picolinylidene-16-one (10 and 11), and 17-picolyl-16-one (15) derivatives of androst-5-ene were synthesized in one, two, four and five steps respectively. By the Oppenauer oxidation or dehydration of 2, 7, 10, and 11 with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), the corresponding A and B ring modified derivatives 3, 5, 6, 8, 9, and 12-14 were obtained. The structure of 2 was unambiguously proved by the appropriate X-ray structural analysis. Compounds 3, 5, 9, 12-14 showed inhibitory activity against the enzyme aromatase. Antibacterial activity, toxicity to brine shrimp Artemia salina, antitumor activity against three tumor cell lines (human cervix carcinoma HeLa cells, human melanoma FemX cells, and human myelogenous leukemia K562 cells) and toxicity against peripheral blood mononuclear cells were evaluated. Three tested compounds, namely 11, 13, and 15, showed strong activity against all three cell lines, the IC(50) values being in the range of 4-10 microM.

Structure-activity relationship study of androstene steroids with respect to local anti-inflammatory activity

A sex hormone, 3beta-acetoxy-17beta-hydroxy-androst-5-ene (1) (CAS 1639-43-6), was isolated from aerial parts of Acacia nilotica. This compound is reported to have anti-inflammatory activity. In view of this, considering this molecule as a lead molecule different androstene compounds were synthesized to study their potency and structure-activity relationship with respect to local anti-inflammatory activity. The experiments indicated that 17 ketonic compounds were more active towards inflammation than their oxime analogues. Similarly, for the compounds containing an acetyl group fixed at C-3 position a decreasing trend of activity was observed in the order of ketonic, hydroxyl, oxime and acetyl group, respectively, when these groups are at C-17 position.

Structure elucidation of new compounds from acidic treatment of the progestins gestodene and drospirenone

Gestodene acidic treatment afforded a single rearrangement product, namely 13-beta-ethyl-18,19-dinorpregna-4,14,16-trien-3,20-dione 3, which was originated through HCl-catalyzed Rupe rearrangement. Drospirenone acidic treatment yielded two epimeric lactones by addition of HCl to the 6beta,7beta-cyclopropane ring, namely 7beta-(chloromethyl)-15beta,16beta-methylene-3-oxo-17beta-pregn-4-ene-21,17-carbolactone 4 and 7beta-(chloromethyl)-15beta,16beta-methylene-3-oxo-17alpha-pregn-4-ene-21,17-carbolactone 5. The structure of the compounds was assessed by spectroscopic and crystallographic methods.

A versatile synthesis of 17-heteroaryl androstenes via palladium-mediated Suzuki cross-coupling with heteroaryl boronic acids

Suzuki coupling of 17-iodoandrosta-5,16-dien-3beta-ol (1) and 17-iodoandrosta-4,16-dien-3-one (2) with nine heteroaryl boronic acids (mainly 2- or 3-furanyl, thienyl, benzofuranyl and benzothienyl boronic acid derivatives) were carried out under normal Suzuki condition (Pd(PPh(3))(4), 2M Na(2)CO(3) and MeOH), generally yielded C(17)-heteroaryl steroids in moderate (10-60%) yields, but furanyl-2- and 5-chlorothienyl-2-boronic acid did not give any coupling product.

Molecular cloning and regulation of porcine SULT2A1: relationship between SULT2A1 expression and sulfoconjugation of androstenone

Hydroxysteroid sulfotransferase (SULT2A1) is a key enzyme in the testicular and hepatic metabolism of 5alpha-androstenone, which is a major component of the off-odor and off-flavor in pork known as boar taint. The goals of this study were to determine the role of testicular and hepatic SULT2A1 activity on plasma 5alpha-androstenone sulfate levels, the accumulation of 5alpha-androstenone in adipose tissue, and to gain insight into the regulatory control of SULT2A1. Testicular SULT2A1 activity was negatively correlated (r = -0.57; P < 0.01) with 5alpha-androstenone concentrations in fat. The differences observed in SULT2A1 activity warranted investigation into potential genetic variation within porcine SULT2A1. The cDNA sequence of porcine Sult2A1 was determined to be > 82% homologous to the human, mouse, and rat Sult2A1 genes. A single nucleotide polymorphism was detected within the coding region of the Sult2A1 from individual testes and liver samples; however, this did not affect the amino acid sequence of the enzyme. Western blot analysis determined that animals with high concentrations of 5alpha-androstenone in fat and low SULT2A1 activity had corresponding low levels of SULT2A1 protein compared with animals with low levels of 5alpha-androstenone in fat. Real-time PCR analysis indicated that Sult2A1 mRNA was increased 2.8-fold in animals with high levels of the protein relative to animals with low levels of the protein. Furthermore, we demonstrated the positive role of the nuclear receptors constitutive androstane receptor and pregnane X receptor, as well as the possible role of farnesoid X receptor in the regulation of testicular SULT2A1 activity. Together, the results of this study suggest that differences in SULT2A1 expression can influence 5alpha-androstenone accumulation in fat.

Ring-B functionalized androst-4-en-3-ones and ring-C substituted pregn-4-en-3-ones undergo differential transformation in Aspergillus tamarii KITA: Ring-A transformation with all C-6 substituted steroids and ring-D transformation with C-11 substituents

The fungus Aspergillus tamarii transforms progesterone 1 into testololactone 5 in high yield through a four-step enzymatic pathway which is flexible to a range of steroidal substrates. To date, no studies have investigated the fate of C-6 (ring-B) and C-11 (ring-C) functionalized steroidal substrates on metabolism. Remarkably all of the C-6 functionalized substrates underwent reductive metabolism on ring-A in contrast to C-11 functionalized steroids where only ring-D oxidative or reductive transformation occurred. In order to discern the precise role of the functional groups in directing metabolism 6-ketoprogesterone 10 with functionality at C-6 and the ring-D methyl ketone underwent reductive and oxidative transformation on both terminal A and D rings showing that this functionality was directing metabolism. Androst-4-en-3,6-dione 12 devoid of ring-D functionality underwent reductive metabolism on ring-A proving that the C-6 functionality was directing metabolism to this ring with the ring-D methyl ketone responsible for generating transformation at this position. Functionality at C-11 exclusively controlled entry into and degree of metabolism on the lactonization pathway. These novel findings may have important bearing in the future understanding of structure activity relationships in revealing new metabolic pathways and further affords a unique opportunity for generation of novel bioactive steroidal compounds.

Synthesis of fluorescent derivatives of wortmannin and demethoxyviridin as probes for phosphatidylinositol 3-kinase

Fluorescent analogs were synthesized of the potent PI 3-kinase inhibitors, wortmannin and demethoxyviridin. The esterification of 11-deacetylwortmannin, 17-hydroxywortmannin, and demethoxyviridin with the fluorescent carboxylic acids NBD-sarcosine and 7-dimethylaminocoumarin-4-acetic acid generated six novel fluorescent esters. Potent inhibition of PI 3-kinase-alpha was observed for the derivatives of 11-desacetylwortmannin and demethoxyviridin.

Quantitative analysis of androst-4-ene-3,6,17-trione and metabolites in human urine after the administration of a food supplement by liquid chromatography/ion trap-mass spectrometry

6-OXO, a new nutritional supplement commercially available on the internet, is sold as an aromatase-inhibitor and contains androst-4-ene-3,6,17-trione as active ingredient. This anabolic steroid is a prohibited substance in sports. Androst-4-ene-3,6,17-trione is metabolised to androst-4-ene-6alpha-ol-3,17-dione and androst-4-ene-6alpha,17beta-diol-3-one. A fast, sensitive and accurate LC/MS method was developed and validated for the quantification of androst-4-ene-3,6,17-trione and its metabolites in urine. The method is capable of determining the stereochemical position of the hydroxy-group at C-6 of the metabolites and consists of a liquid-liquid extraction step with diethylether after enzymatic hydrolysis, followed by separation on a reversed phase column. Ionisation of the analytes is carried out using atmospheric pressure chemical ionisation. The limit of quantification of the method was 5 ng/mL for all compounds. The accuracy ranged from 14.8 to 1.3% for androst-4-ene-3,6,17-trione, 9.4 to 1.6% for androst-4-ene-6alpha-ol-3,17-dione and 4.1 to 3.2% for androst-4-ene-6alpha,17beta-diol-3-one in the range of 5-1000 ng/mL. Using this method androst-4-ene-6alpha-ol-3,17-dione was identified as a major urinary metabolite, whereas androst-4-ene-6alpha,17beta-diol-3-one as a minor metabolite. While the parent compound is predominantly excreted in conjugated form, both metabolites are solely excreted as conjugates.

Comparison of effects of U18666A and enantiomeric U18666A on sterol synthesis and induction of apoptosis

Treatment of animals or cells with the amphipathic tertiary amine U18666A {3beta-[2-(diethylamino) ethoxy]androst-5-en-17-one} provides models for several human diseases (e.g., cataracts, Niemann-Pick disease, and epilepsy). Although U18666A can inhibit several enzymes in the cholesterol synthesis pathway, we hypothesized that induction of these varied conditions was due to physical effects of the amine rather than to inhibition of specific proteins. To test this possibility we compared the capacity of U18666A and its enantiomer, ent-U18666A, to inhibit net sterol synthesis and induce apoptosis in cultured bovine lens epithelial cells. Nonenantiospecific actions dependent on the physical properties of these mirror image molecules would be identical, but effects dependent upon enantiospecific interactions would be different for the enantiomers. At the same concentrations, both forms of the compound equally inhibited sterol synthesis and induced apoptosis. These observations supported a generalized mechanism of enzyme inhibition such as perturbation of the microenvironment of endoplasmic enzymes and alteration of membrane order, perhaps of the mitochondrial membrane, to explain induction of apoptosis.

Quantitative analysis of gene regulation by seven clinically relevant progestins suggests a highly similar mechanism of action through progesterone receptors in T47D breast cancer cells

Progesterone (P4) is an essential reproductive steroid hormone required for many aspects of female reproductive physiology. Progestins are compounds that demonstrate progesterone-like activity and are used in oral contraception, hormone therapy, and treatment of some reproductive disorders, but differ widely in their chemical structures, potency, and pharmacokinetics. While numerous studies have assessed progestins on specific endpoints, little is known about the activation of global gene expression by progestins. We used Affymetrix GeneChip U133A expression arrays to examine the action of P4 and six clinically relevant synthetic progestins (3-ketodesogestrel, drospirenone, levonorgestrel, medroxyprogesterone acetate, norethindrone acetate, and trimegestone) on the progesterone receptor (PR)-positive T47Dco and the PR-negative T47D-Y breast cancer cell lines. Excluding drospirenone, one or more of the progestins-regulated 329 genes, with 30 genes regulated by at least 2.0-fold by all progestins in the T47Dco cells. The synthetic progestins show a high degree of similarity in their transcriptional responses, and each progestin regulates between 77 and 91% of the genes regulated by P4. Independent quantitative RT-PCR analysis confirmed a similar regulation for S100P, PPL, IL20RA, NET1, ATP1A1, HIG2, and CXCL12 (SDF-1) by all seven progestins. Attempts to find differentially regulated genes by any progestin compared to all other treatments failed, suggesting any differences are quantitative, not qualitative. This analysis demonstrates a high degree of similarity among these progestins on PR-regulated gene expression in T47D cells, suggesting a similar and fairly specific mode of action.

Etienic etienate as synthon for the synthesis of steroid oligoester gelators

Linear oligoesters based on etienic acid (3beta-hydroxyandrost-5-ene-17beta-carboxylic acid) containing four steroid units were prepared using a 2+2 synthetic strategy in a successful synthesis of 3beta-{[3beta-({3beta-[(3beta-hydroxyandrost-5-ene-17beta-carbonyl)oxy]androst-5-ene-17beta-carbonyl}oxy)androst-5-ene-17beta-carbonyl]oxy}androst-5-ene-17beta-carboxylic acid. The main problems with deprotection were overcome by using orthogonal groups as O-nitrates and 2-(trimethylsilyl)ethyl ethers.

HPTLC chromatography of androstene derivates. Application of normal phase thin-layer chromatographic retention data in QSAR studies

The chromatographic behavior of seven 16-oximino derivatives of 3beta-hydropxy-5-androstene have been investigated using the normal-phase (NP) HPTLC chromatographic mode of the type silica-non-polar diluent (benzene)-polar modifier (acetonitrile, ethyl acetate, or dioxane). The linear relationship between the retention constants (R(M)) and the logarithm of the organic modifier content in the mobile phase allowed for the calculation of R(M)0 values. The influence of substituent in the molecule on extrapolated retention data is discussed. To better understand the retention mechanism in the separation of androstene compounds, the functional group contributions (tauX) were compared with Hansch substituent constants (pi). An attempt to quantitate the lipophilicity of the investigated compounds using normal phase thin-layer chromatographic R(M)0 value was made. Also, the relative lipophilicity values determined previously by RPC as well as activity were compared with NPC data.

Testicular sulfoconjugation of the 16-androstene steroids by hydroxysteroid sulfotransferase: Its effect on the concentrations of 5α-androstenone in plasma and fat of the mature domestic boar1

This study examined the relationship between sulfoconjugation and the degree to which 5alpha-androstenone can accumulate in fat. Analysis of the unconjugated and sulfoconjugated fractions of peripheral plasma from 25 mature Yorkshire boars and testicular vein plasma from an additional 20 mature Yorkshire boars revealed that the majority of 5alpha-androstenone is present as a sulfoconjugate, reaching levels up to 69 +/- 4.3 and 72 +/- 6.2%, respectively, relative to its unconjugated form. The presence of this steroid in the sulfoconjugate fraction was confirmed by gas chromatography-mass spectrometry. Plasma concentrations of 5alpha-androstenone in the sulfoconjugate fraction were negatively correlated (r = -0.36; P < 0.01) with the concentrations of 5alpha-androstenone in fat. High concentrations of 5alpha-androstenone in the sulfate fraction were only associated with animals that had fat androstenone concentrations < 0.5 microg/g. In addition, there was a positive correlation (r = 0.31; P < 0.01) between the concentrations of unconjugated 5alpha-androstenone in plasma and 5alpha-androstenone in fat. These findings indicate that the levels of the sulfoconjugated form present in the peripheral plasma influence the accumulation of 5alpha-androstenone in fat. The specific sulfotransferase enzyme involved in sulfoconjugating these steroids was identified by incubating Leydig cells with specific sulfotransferase inhibitors for 8 h. It was discovered that the enzyme responsible for the sulfoconjugation of the 16-androstene steroids is hydroxysteroid sulfotransferase. Hydroxysteroid sulfotransferase may play a significant role in determining the levels of sulfated 16-androstene steroids present in plasma. The results of this study indicate that sulfoconjugation may serve to regulate the quantity of unconjugated 5alpha-androstenone present in the circulation and thus available for accumulation. Animals with a decreased ability to sulfoconjugate 5alpha-androstenone would have a subsequent increase in the levels of unconjugated 5alpha-androstenone in circulation, allowing for the accumulation of high levels in fat and thereby potentially leading to the development of boar taint.

Detection of androst-4-ene-3,6,17-trione (6-OXO®) and its metabolites in urine by gas chromatography-mass spectrometry in relation to doping analysis

The metabolism and excretion of androst-4-ene-3,6,17-trione after administration of the 'nutritional' supplement 6-OXO was investigated by gas chromatography-mass spectrometry (GC-MS) in full-scan mode. The parent drug androst-4-ene-3,6,17-trione and androst-4-ene-6alpha,17beta-diol-3-one and androst-4-ene-6alpha-ol-3,17-dione were detected in the post-administration urine samples. Because androst-4-ene-3,6,17-trione is an anabolic steroid and an aromatase inhibitor, this substance is regarded as a doping agent. Hence, a selective and sensitive GC-MS method in selected ion monitoring mode for the detection of the TMS-enol-TMS-ether derivatives of these substances was developed and validated for doping control purposes. The limit of detection (LOD) of the investigated compounds ranged from 5 to 10 ng/mL. Using this method, the detection time for androst-4-ene-3,6,17-trione and androst-4-ene-6alpha,17beta-diol-3-one was 24 h, while androst-4-ene-6alpha-ol-3,17-dione could be detected up to 37 h after administration of the dose recommended by the manufacturer.

The allylic 7-ketone at the steroidal skeleton is crucial for the antileukemic potency of chlorambucil’s active metabolite steroidal esters

We have investigated the role of the allylic 7-ketone in oxidized Delta5-steroids on antileukemic activity. We synthesized and studied a series of oxidized and non-oxidized steroidal esters of p-N,N-bis(2-chloroethyl)aminophenylacetic acid (PHE), chlorambucil's active metabolite. In a comparative study of these 7-keto derivatives, on a molecular basis, regarding their ability to induce sister chromatid exchanges (SCEs) and to inhibit cell proliferation in normal human lymphocytes in vitro, the results with these 7-keto derivatives, on a molecular basis, correlated well with their antileukemic potency against leukemia P388- and L1210-bearing mice, which proved to be significantly increased compared to that of the non-oxidized derivatives. Our results indicate that the role of the steroidal skeleton it is not only for the transportation of the alkylating agent into the cell, but also contributes directly to the mechanism of antileukemic action, by an as-yet unknown way. The main conclusion from this study is that the existence of the allylic 7-keto group in the skeleton of the Delta5-steroidal esters impressively enhances their antileukemic activity, while the toxicity remains at clinically acceptable levels, suggesting that this structural modification should be further investigated.

Structure–activity relationships in 4- and 5-androstene: 3β-acetoxy-17-methyl-17-oxo-16,17-seco-5-androstene-16-carbonitrile and 17-methyl-3,17-dioxo-16,17-seco-4-androstene-16-carbonitrile

The title compounds, C22H31NO3 and C20H27NO2, have similar conformations except in the molecular geometry and the bonding of two of the rings. These differences lead to marked differences in the biological activities of these compounds. Molecules of both compounds are linked by weak C-H...O hydrogen bonds in the crystal structures.

Synthesis and biological evaluation of synthetic viridins derived from C(20)-heteroalkylation of the steroidal PI-3-kinase inhibitor wortmannin

A series of viridin analogs was prepared from wortmannin by nucleophilic ring opening at C(20) and evaluated against the signaling kinases PI-3-kinase and mTOR. Several subnanomolar enzyme inhibitors with orders of magnitude selectivity for PI-3-kinase and strong cytotoxic activity against four cancer cell lines were identified. Among the ten most promising derivatives, six demonstrated lower liver toxicity and greater promise for inhibition of tumor cell growth than the lead structure wortmannin.

[Biotransformation of dehydroepiandrosterone by hairy root cultures of Anisodus tanguticus]

AIM

To modify the structure of dehydroepiandrosterone (DHEA).

METHODS

Using hairy root cultures of Anisodus tanguticus to perform biotransformation of DHEA, using chromatographic and spectral techniques to isolate and identify the products.

RESULTS

(1) The MS medium without plant hormone was suitable for the growth of the hairy root. (2) DHEA was converted into five products: androst-4-ene-3, 17-dione (I); 6alpha-hydroxyandrost-4-ene-3, 17-dione (II); 6alpha, 17beta-dihydroxyandrost-4-ene-3-one (III); androst-4-ene-3, 6, 17-trione (IV) and 17beta-hydroxyandrost-4-ene-3-one (V).

CONCLUSION

It is the first time to use hairy root cultures of Anisodus tanguticus for the biotransformation of DHEA and five DHEA-related compounds were obtained.

New compounds from an extract of Vernonia colorata leaves with anti-inflammatory activity

Bioassay-directed fractionation of an anti-inflammatory CHCl(3)-MeOH (9:1) extract of leaves of Vernonia colorata, using a carrageenan-induced rat paw model, led to the isolation of six new compounds (1-6). These were assigned as two new androst-8-en glycosides, 3-O-[beta-d-galactopyranosyl-(1-2)-[beta-d-glucopyranosyl-(1-->6)]-beta-d-glucopyranoside]-5alpha,14alpha-androst-8-ene (1) and 3-O-[beta-d-glucopyranosyl-(1-->6)-beta-d-glucopyranoside]-5alpha,14alpha-androst-8-ene (2), two new stigmastane-type glycosides, 3beta,21,24-trihydroxy-21,23;22,28;26,28-triepoxy-5alpha-stigmasta-8(9),14(15)-dien-3-O-beta-d-galactopyranosyl-(1-->2)-beta-d-glucopyranoside (3) and 3beta,21,24-trihydroxy-21,23;22,28;26,28-triepoxy-5alpha-stigmasta-8(9),14(15)-dien-3-O-beta-d-galactopyranosyl-(1-->2)-beta-d-(6-acetyl)glucopyranoside (4), and two new stigmastane-type steroids, 3beta,25,29-trihydroxy-5alpha-stigmasta-8(9),14(15),24Z(28)-triene (5) and 3beta,23,25-trihydroxy-24,28-epoxy-5alpha-stigmasta-8(9),14(15)-diene (6). The structures of 1-6 were elucidated by spectral and chemical studies. Compounds 1-6 were tested for the anti-inflammatory activity, but all were inactive or weakly inactive as anti-inflammatory agents.

The steroidal analog GW707 activates the SREBP pathway through disruption of intracellular cholesterol trafficking

Recently, a new class of lipid-lowering agents has been described that upregulate LDL receptor (LDLr) activity. These agents are proposed to activate sterol-regulated gene expression through binding to the sterol regulatory element binding protein (SREBP) cleavage-activating protein (SCAP). Here, we show that the steroidal LDLr upregulator, GW707, induces accumulation of lysosomal free cholesterol and inhibits LDL-stimulated cholesterol esterification, similar to that observed in U18666A-treated cells and in Niemann-Pick type C1 (NPC1) mutants. Moreover, we demonstrate that induction of the NPC-like phenotype by GW707 is independent of SCAP function. We find that treatment with GW707 does not increase SREBP-dependent gene expression above that observed in lipoprotein-starved cells. Rather, we show that the apparent increase in SREBP-dependent activity in GW707-treated cells is attributable to a failure to appropriately suppress sterol-regulated gene expression, as has been shown previously for U18666A-treated cells and NPC mutant fibroblasts. We further demonstrate that cells treated with either GW707 or U18666A fail to appropriately generate 27-hydroxycholesterol in response to LDL cholesterol. Taken together, these findings support a mechanism in which GW707 exerts its hypolipidemic effects through disruption of late endosomal/lysosomal sterol trafficking and subsequent stimulation of LDLr activity.

Two androst-5-ene derivatives: 16-[4-(3-chloropropoxy)-3-methoxybenzylidene]-17-oxoandrost-5-en-3 beta-ol and 16-[3-methoxy-4-(2-pyrrolidin-1-ylethoxy)benzylidene]-3 beta-pyrrolidinoandrost-5-en-17 beta-ol monohydrate

In the steroidal nucleus of 16-[4-(3-chloropropoxy)-3-methoxybenzylidene]-17-oxoandrost-5-en-3 beta-ol, C(30)H(29)ClO(4), (I), the outer two six-membered rings are in chair conformations, while the five-membered ring and the central six-membered ring of the steroidal nucleus adopt half-chair and envelope conformations, respectively. In 16-[3-methoxy-4-(2-pyrrolidin-1-ylethoxy)benzylidene]-3 beta-pyrrolidinoandrost-5-en-17 beta-ol monohydrate, C(37)H(54)N(2)O(3).H(2)O, (II), one C atom of one of the outer six-membered rings of the steroid nucleus and the four C atoms of the ethoxypyrrolidine ring are disordered over two sites. The five-membered ring, and the central and one of the outer six-membered rings of the steroidal nucleus exhibit distorted half-chair, chair and envelope conformations, respectively. In (I), intermolecular O-H...O hydrogen bonds link the molecules into chains via a co-operative O-H...O-H...O-H pattern. In (II), intermolecular O-H...O and O-H...N hydrogen bonds link the steroid and water molecules alternately into extended chains.

Newly identified steroid hormone in urine of patients with Cushing's syndrome: 3alpha,11 beta-dihydroxy-4-androsten-17-one

We have previously reported that the urine of patients with Cushing's syndrome, including pituitary adenoma cases and adrenal adenoma cases, consistently show a conspicuous peak in the chromatographical analysis of 17-ketosteroid fraction but not in the urine of control subjects. The substance emerges just before 11beta-hydroxy-androsterone (11beta-OH-A) in capillary gas chromatography. In the present study, we have identified an "unknown peak substance" observed in the urine of Cushing's syndrome patients using gas chromatography-mass spectrometry (GC/MS). Trimethylsilylether (TMS)-derivative of the substance was found to have a molecular weight (MW) of 448, which is similar to that of 11-OH-A (MW: 450). From these findings, we hypothesized that the substance had the structure of a C-19 steroid with two hydroxyl groups at positions C-3 and C-11, one keto-group at C-17 and a double bond between C-4 and C-5 of the A ring. We hypothesized that the unknown peak substance was 3alpha,11beta-dihydroxy-4-androsten-17-one (3alpha,11beta-DH-A). To confirm this speculation we synthesized 3alpha,11beta-DH-A and compared the elution pattern of it with that of the "unknown peak substance" using GC and GC/MS. We found that both substances were indistinguishable by GC and GC/MS analysis. These results suggest that the unknown substance observed in the urine of patients with Cushing's syndrome is 3alpha,11beta-DH-A.

Synthesis, X-ray crystal structures and biological activity of 16-amino-17-substituted-D-homo steroid derivatives

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.

Photoinduced intramolecular electron transfer and triplet energy transfer in a steroid-linked norbornadiene-carbazole dyad

Bichromophoric compound 3 beta-((2-(methoxycarbonyl)bicyclo[2.2.1]hepta-2,5-diene-3-yl)carboxy)androst-5-en-17 beta-yl-[2-(N-carbazolyl)acetate] (NBD-S-CZ) was synthesized and its photochemistry was examined by fluorescence quenching, flash photolysis, and chemically induced dynamic nuclear polarization (CIDNP) methods. Fluorescence quenching measurements show that intramolecular electron transfer from the singlet excited state of the carbazole to the norbornadiene group in NBD-S-CZ occurs with an efficiency (Phi SET) of about 14 % and rate constant (kSET) of about 1.6 x 10(7) s-1. Phosphorescence and flash photolysis studies reveal that intramolecular triplet energy transfer and electron transfer from the triplet carbazole to the norbornadiene group proceed with an efficiency (TET + TT) of about 52 % and rate constant (kTET + kTT) of about 3.3 x 10(5) s-1. Upon selective excitation of the carbazole chromophore, nuclear polarization is detected for protons of the norbornadiene group (emission) and its quadricyclane isomer (enhanced absorption); this suggests that the isomerization of the norbornadiene group to the quadricyclane proceeds by a radical-ion pair recombination mechanism in addition to intramolecular triplet sensitization. The long-distance intramolecular triplet energy transfer and electron transfers starting both from the singlet and triplet excited states are proposed to proceed by a through-bond mechanism.

Solid phase transition of CS-891 enantiotropes during grinding

The physical properties of N-[1-(4-methoxyphenyl)-1-methylethyl]-3-oxo-4-aza-5a-androst-1-ene-17beta-carboxamide (CS-891), a novel and orally effective testosterone 5-reductase inhibitor, were investigated by differential scanning calorimetry, powder X-ray diffraction at elevated temperature and single crystal X-ray crystallography. CS-891 was revealed to exist as two enantiotropic forms, a low-temperature stable form (Form A) and a high-temperature stable form (Form B) which reversibly transforms to Form A at around 58 degrees C. The effect of grinding temperature on the transition of CS-891 between the amorphous and the crystalline state during grinding of the eantiotropes was examined. Form A transformed into an amorphous form during the grinding process while the product temperature was kept below the transition temperature. On the other hand, when the product temperature during grinding reached above the transition temperature, Form A transformed into an amorphous form and some of the amorphous form converted back to Form B. Form B crystallized from the amorphous form was physically stable even at below the transition temperature. The amorphous form in equilibrium with Form B exhibited remarkable physical stability in comparison with the amorphous form obtained by continued grinding below the transition temperature.

Progress Toward a High-Affinity Allosteric Enhancer at Muscarinic M1 Receptors

Loss of forebrain acetylcholine is an early neurochemical lesion in Alzheimer's disease (AD). As muscarinic acetylcholine receptors are involved in memory and cognition, a muscarinic agonist could therefore provide a "replacement therapy" in this disease. However, muscarinic receptors occur throughout the CNS and the periphery. A selective locus of action of a muscarinic agonist is therefore crucial in order to avoid intolerable side effects. The five subtypes of muscarinic receptors, M1-M5, have distinct regional distributions with M2 and M3 receptors mediating most of the peripheral effects. M1 receptors are the major receptor subtype in the cortex and hippocampus-the two brain regions most associated with memory and cognition. This localization has led to a, so far unsuccessful, search for a truly M1-selective muscarinic agonist. However, acetylcholinesterase inhibitors, such as donepezil (Aricept), which potentiate cholinergic neurotransmission, do have a therapeutic role in the management of AD and so the M1 receptor remains a viable therapeutic target. Our approach is to develop muscarinic allosteric enhancers-compounds that bind to the receptor at an "allosteric" site, which is distinct from the "primary" site to which ACh binds, and which enhance ACh affinity (or efficacy). Having discovered that a commercially available compound, WIN 62577, is an allosteric enhancer with micromolar potency at M3 receptors, we report here some results of a chemical synthesis project to develop this hit. Modification of WIN 62577 has led to compounds with over 1000-fold increased affinity but, so far, none of these extremely potent compounds are allosteric enhancers.

Syntheses and advanced NMR structure determination of androsteno-[17,16-d]-pyrimidine derivatives

Reactions of 16-hydroxymethylene- and 16-aminomethylene-3beta-hydroxy-5-androsten-17-one with formamide and guanidine were carried out resulting in the formation of [16,17-d]-pyrimidine rings. Advanced two-dimensional NMR methods were used to investigate the structure of the products. Homonuclear-, and heteronuclear chemical shift correlation experiments yielded the complete 1H-, 13C- and 15N signal assignment for these compounds.

Selective uptake from LDL is stimulated by unsaturated fatty acids and modulated by cholesterol content in the plasma membrane: role of plasma membrane composition in regulating non-SR-BI-mediated selective lipid transfer

We previously reported that unsaturated fatty acids stimulated low-density lipoprotein (LDL) particle uptake in J774 macrophages by increasing LDL receptor activity. Since free fatty acids (FFA) also change plasma membrane properties, a putative cholesteryl ester (CE) acceptor for selective uptake (SU), we questioned the ability of FFA to modulate SU from LDL. Using [(3)H]cholesteryl ether/(125)I-LDL to trace CE core and whole particle uptake, we found that oleic acid and eicosapentaenoic acid, but not saturated stearic acid, increased SU by 30% over control levels. An ACAT inhibitor, Dup128, abolished FFA effects on SU, indicating that increased SU by FFA was secondary to changes in cell-free cholesterol (FC). Consistent with these observations, ACAT inhibition increased cell FC and reduced LDL SU by half. The important role of plasma membrane composition was further demonstrated in that beta-cyclodextrin- (beta-CD-) mediated FC removal from the plasma membrane increased SU from LDL and was further stimulated by U18666A, a compound that inhibits FC transport between lysosomes and the plasma membrane. In contrast, cholesterol-saturated beta-CD markedly reduced LDL SU. In contrast to LDL SU, oleic acid, ACAT inhibition, U18666A, or beta-CD had no effects on HDL SU. Moreover, HDL SU was inhibited by antimouse SR-BI antibody by more than 50% but had little effect on LDL SU. In C57BL/6 mice fed a high fat diet, plasma FFA levels increased, and SU accounted for an almost 4-fold increased proportion of total cholesterol delivery to the arterial wall. Taken together, these data suggest that LDL SU is mediated by pathways independent of SR-BI and is influenced by plasma membrane FC content. Moreover, in conditions where elevated plasma FFA occur, SU from LDL can be an important mechanism for cholesterol delivery in vivo.

X-ray and deuterium labeling studies on the abnormal ring cleavages of a 5 beta-epoxide precursor of formestane

A new convergent synthesis of the antitumor steroid formestane (4-OHA) 5 has been performed from the easily available epimeric mixture of 5 alpha- and 5 beta-androst-3-en-17-one 1a and 1b in order to attempt a yield improvement. A two-step oxidative route followed by base-catalyzed isomerization was applied to the 5 alpha- and 5 beta-epimers 1a and 1b, either as a mixture or separately, leading to the title compound 5. From epimer 1a an efficient process was attained to prepare the desired aromatase inhibitor formestane. Epimer 1b led to the formation of the same compound 5. Additionally, 1b have also been converted in 5 beta-hydroxyandrostane-3,17-dione 12 and androst-4-ene-3,17-dione 13, revealing an unexpected reactivity of the 3 beta,4 beta-epoxy-5 beta-androstan-17-one intermediate 6 formed from 1b during the first oxidative step with performic acid. Cleavage of the epoxide 6 led to the trans-diaxial and the trans-diequatorial vic-diols 7 and 8 and to the 1,3-diol 9. The formation of the abnormal products 8 and 9 were investigated through X-ray and deuterium labeling studies. Diol 8 was formed through a trans-diequatorial epoxide ring opening and the 1,3-diol 9 was formed through an intramolecular rearrangement involving a 1,2-hydride shift. All the vic-diols 3, 7 and 8 formed, proved to be good precursors for the synthesis of the target compound 5.

4-(3,17-Dioxoandrost-4-en-16-ylidenemethyl)benzonitrile

The title compound, C(27)H(29)NO(2), has the outer six-membered ring in a sofa conformation, while the central rings are in chair conformations. The five-membered ring adopts a slightly distorted 13 beta,14 alpha-half-chair conformation. The cyanobenzylidene moiety has an E configuration with respect to the carbonyl group at position 17.

Bioactivation of the carcinogen 11-methoxy-16, 17-dihydro-15H-cyclopenta[a]phenanthrene

The title compound is a more potent carcinogen than would be anticipated from its simple phenanthrene structure lacking further D-ring conjugation. In vitro it undergoes microsomal metabolism to yield as major metabolites its 15- and 17-alcohols and its 16, 17-diol; other minor metabolites are also derived from attack at the 5-membered ring, but no evidence of aromatic oxidation is apparent. The title compound is a weak mutagen in the Ames' test with Salmonella typhimurium TA100, but only with microsomal bio-activation. The 17-ol and 16,17-diol are inactive, with or without biological activation. By contrast the 15-alcohol, a rather reactive compound, is a strong mutagen both in the presence and absence of the bio-activation system. This, therefore, may be the proximate carcinogen, and its structural analogy to the naturally occurring hepato-carcinogen safrole is noted.

Steroid transformations with Fusarium oxysporum var. cubense and Colletotrichum musae

The utility of two locally isolated fungi, pathogenic to banana, for steroid biotransformation has been studied. The deuteromycetes Fusarium oxysporum var. cubense (IMI 326069, UAMH 9013) and Colletotrichum musae (IMI 374528, UAMH 8929) had not been examined previously for this potential. In general, F. oxysporum var. cubense effected 7alpha hydroxylation on 3beta-hydroxy-delta5-steroids, 6beta, 12beta, and 15alpha hydroxylation on steroidal-4-ene-3-ones, side-chain degradation on 17alpha,21-dihydroxypregnene-3,20-diones, and 15alpha hydroxylation on estrone. Both strains were shown to perform redox reactions on alcohols and ketones.

The effect of 4beta and 19 ester functionalities on some electrophilic addition reactions of delta5-steroids

The reactions of 3beta-acyloxyandrost-5-enes with bromine/silver acetate (Petrow reaction) and mercury(II) trifluoroacetate (modified Treibs oxidation) have been used previously to effect allylic oxidation on these substrates en route to biologically active compounds. In both these reactions, which involve electrophilic addition to the delta5-bond, the 3-acyloxy substituent plays a significant role. In this report, the effect of introducing other substituents proximate to the delta5-bond has been studied by using derivatives of 3beta-acetoxyandrost-5-en-17-one (1), namely, 3beta,4beta-diacetoxyandrost-5-en-17-one (13), 3beta,19-diacetoxyandrost-5-en-17-one (14), 3beta-acetoxyandrost-5-ene-7,17-dione (15), and 3beta-acetoxy-4,4-dimethylandrost-5-en-17-one (17). Our results indicate that in both sets of reactions the effect of the introduced functional groups was pronounced. In the Petrow reaction, electrophilic addition rather than allylic oxidation on the diacetates was observed. With the Treibs reaction, allylic oxidation on the diacetates occurred. The 7-keto and 4,4-dimethyl steroids proved to be poor substrates in both reactions.

Isolation and characterization of viridin, a new 65 kDa antifungal protein from the mould Trichoderma viride

A new extracellular antifungal protein with a yield of 10 mg per liter was isolated from the culture medium of the mould Trichoderma viride. The protein, which we named viridin, was purified by carboxymethyl-cellulose cation-exchange chromatography and Superose 12 HR 10/30 high-performance liquid chromatography. Viridin, a basic protein of approximately 65 kDa as determined by SDS-PAGE, inhibits the growth of the cotton pathogen Verticillum dahliae, the IC50 being 6 microM.

Use of the steroid derivative RPR 106541 in combination with site-directed mutagenesis for enhanced cytochrome P-450 3A4 structure/function analysis

RPR 106541 (20R-16alpha,17alpha-[butylidenebis(oxy)]-6al pha, 9alpha-difluoro-11beta-hydroxy-17beta-(methylthio)androst a-4-en-3-one) is an airway-selective steroid developed for the treatment of asthma. Two metabolites produced by human liver microsomes were identified as R- and S-sulfoxide diastereomers based on liquid chromatography/mass spectrometry analysis, proton nuclear magnetic resonance, and cochromatography with standards. Sulfoxide formation was determined to be cytochrome P-450 (CYP) 3A4-dependent by correlation with CYP3A4-marker nifedipine oxidase activity, inhibition by cyclosporin A and troleandomycin, and inhibition of R- (70%) and S- (64%) sulfoxide formation by anti-3A antibody. Expressed CYP2C forms catalyzed RPR 106541 sulfoxidation; however, other phenotyping approaches failed to confirm the involvement of CYP2C forms in these reactions in human liver microsomes. Expressed CYP3A4 catalyzed the formation of the sulfoxide diastereomers in a 1:1 ratio, whereas CYP3A5 displayed stereoselectivity for formation of the S-diastereomer. The high rate of sulfoxidation by CYP3A4 and the blockage of oxidative metabolism at the electronically favored 6beta-position provided advantages for RPR 106541 over other substrates as an active site probe of CYP3A4. Therefore, oxidation of RPR 106541 by various CYP3A4 substrate recognition site (SRS) mutants was assessed. In SRS-4, A305V and F304A showed dramatically reduced rates of R-diastereomer formation (83 and 64% decreases, respectively), but S-diastereomer formation was affected to a lesser extent. A370V (SRS-5) showed decreased formation of the R-sulfoxide (52%) but increased formation of the S-diastereomer. In the SRS-2 region, the most dramatic change in sulfoxide ratios was observed for L210A. In conclusion, the structure of RPR 106541 imposes specific constraints on enzyme binding and activity and thus represents an improved CYP3A4 probe substrate.

The scope and limitations of the reaction of delta 5-steroids with mercury(II) trifluoroacetate

The effect of the C-3 substituent on the reaction of androst-5-enes with mercury(II) trifluoroacetate in dichloromethane (modified Treibs oxidation) was investigated. 3 beta-Acyloxyandrost-5-en-17-ones gave 3 beta-acyloxy-6 beta-hydroxyandrost-4-en-17-ones accompanied by 3 beta-acyloxy-6-chloromercuriandrost-5-en-17-ones. 3 beta-Acetoxy-6 beta-trifluoroacetoxyandrost-4-en-17-one and 3 beta-acetoxy-4 beta-trifluoroacetoxyandrost-5-en-17-one were revealed to be intermediates in the reaction. The formation of the chloromercury steroids indicated participation in the reaction by the solvent. With 3 alpha-acetoxyandrost-5-en-17-one as substrate, a complete reversal in the product distribution was observed. 3 beta-Haloandrost-5-en-17-ones gave mainly products that reflected SN1 substitution of the halide. 3 beta-Hydroxy- and 3 beta-trifluoroacetoxyandrost-5-en-17-ones were formed. 3 beta-Methoxyandrost-5-en-17-one afforded in nearly identical yields androst-4-ene-3,17-dione, 3 beta-methoxy-6 beta-hydroxyandrost-4-en-17-one, 3 beta-methoxy-6-chloromercuriandrost-5-en-17-one and 6 beta-hydroxyandrost-4-ene-3,17-dione while androst-5-en-17-one yielded 3 beta,6 beta-dihydroxyandrost-4-en-17-one, androst-5-ene-7,17-dione and androst-4-ene-3,17-dione. The effects of solvent and other mercury salts on the reaction were also studied. Treibs oxidation was successful in chloroform, carbon tetrachloride, and dibromomethane, but not in other solvents tested. 3 beta-Acetoxy-6-bromomercuriandrost-5-en-17-one was obtained in dibromomethane. Replacement of the reagent by mercury(II) trichloroacetate altered the intermediates formed but not the products. Mercury(II) tribromoacetate was unreactive, however.

Heck reactions of steroidal alkenyl iodides

Heck reactions of some steroid derivatives possessing iodo-alkenyl moiety (17-iodo-androst-16-ene, 1, 17-iodo-4-aza-4-methyl-androst-16-en-3-one, 2, 17-iodo-4-aza-androst-16-en-3-one, 3) were carried out in the presence of palladium catalysts using various olefins (methyl acrylate, ethyl methacrylate, allyl alcohol and allyl acetate) as coupling partners. With methyl acrylate, a side reaction was observed: the coupling product underwent a Diels-Alder reaction with the excess of methyl acrylate resulting in a six-membered carbocyclic E-ring. Reaction conditions of the synthesis of the Heck-product were optimized. Although the coupling with allyl alcohol led to the formation of 21-formyl-16-pregnene derivatives, the synthesis of the corresponding steroidal unsaturated alcohol could be achieved only via hydrolysis of the coupling product of the alkenyl iodide with allyl acetate.

A simple two-step method for the conversion of [3H]cortisol to [3H]-11-ketotestosterone

Despite the existence of several protocols, problems appear to persist in the small scale chemical synthesis of radiolabeled 11-ketotestosterone from cortisol. We investigated the possibilities of using the mild oxidant pyridinium dichromate for the oxidative cleavage of the dihydroxyacetone side chain of cortisol and 17 beta-hydroxysteroid dehydrogenase for the subsequent reduction of the resulting 17-keto group. Our protocol has resulted in consistently high yields of both the intermediate, adrenosterone (70-80%), and the product, 11-ketotestosterone (up to 60%). This, taken together with the convenience and relatively low cost of our method, recommends the protocol for its use for the synthesis of [3H]-11-ketotestosterone for endocrine studies.

17-Imidazolyl, pyrazolyl, and isoxazolyl androstene derivatives. Novel steroidal inhibitors of human cytochrome C17,20-lyase (P450(17 alpha)

We recently described a number of inhibitors of P450(17 alpha), the key enzyme of androgen biosynthesis. Here, we report the synthesis and activity of novel 17-imidazolyl, pyrazolyl, and isoxazolyl androstene derivatives as potential agents for the treatment of prostatic cancer. A number of 17-(4'-Imidazolyl) derivatives were prepared by condensing the corresponding 17-ketol acetate side chain with aldehyde and ammonium hydroxide. The 17 beta-(4'imidazolyl) derivatives (2a, 2e, 4a, 4c) were found to be potent inhibitors of human testicular P450(17 alpha), with greater activity than ketoconazole. The juxtaposition between the imidazole ring and the steroid D ring appears to be important in contributing inhibitory properties, Compounds having a 17 beta-(2'-imidazolyl) ring (9a, 10) or a 20 beta-(2'-imidazolyl) ring (12), instead of the 17 beta-(4'-imidazolyl) ring (2a, 4a), are weak inhibitors. Among the 17-(4'-imidazolyl) derivatives, introduction of the 17 alpha-hydroxy group (4b) and 16 alpha,17 alpha-epoxide group (2d) diminished potency (2a-->2d; lC50 66-->430 nM; 4a-->4b; lC50 58-->1200 nM), while the 16,17 double bond increased the inhibitory activity by almost three times in the 5-en-3 beta-ol inhibitors (2a-->2e; lC50 60-->24 nM). There was virtually no difference in the inhibitory activity in the 4-en-3-one inhibitors (4a-->4c; IC50 58-->50 nM). The introduction of a methyl (2b) or phenyl group (2c) on the 2'-position of 4'-imidazolyl ring caused a dramatic decrease in the potency. As to modification of the A,B rings, the 3-acetate (2f, 2g) decreased the potency almost 3-fold compared with the 3-alcohol (2e-->2f, IC50 24-->75 nM; 2a-->2g, 66-->199 nM) and the conversion from the 5-en-3 beta-ol into the 4-en-3-one hardly affected the potency. As expected, 4c was more potent than 2e for the rat p450(17 alpha). 17-(3'Pyrazolyl)-(14b) and 17-(5'-isoxazolyl)-androsta-5,16-dien-3 beta-ol (15b) were also potent inhibitors of P450(17 alpha), whereas the 17-(2'-imidazolyl) compound (9b) was one of the most potent inhibitor in this series. However, their 16-saturated counterparts (9a, 14a, 15a) were weak inhibitors. The 17 beta-(3'-isoxazolyl)- (16) and 17 beta-(5'-methyl-3'-oxazolyl)androst-5-en-3 beta-ol (18) were also inactive. The introduction of a methyl of phenyl group on the nitrogen of the pyrazolyl ring of 14b [see 14c, 14d, and 14e] also caused some loss of inhibition for P450(17 alpha). Compounds 2e, 4a, 4c, 9b, 14d, 17a, and 17b are among the most potent inhibitors of human P450(17 alpha) so far reported.

Synthesis and structure-activity relationships of 6-substituted androst-4-ene analogs as aromatase inhibitors

Series of 6 alpha- and 6 beta-alkyl-substituted androst-4-en-17-ones (18 and 19) and their 17 beta-reduced derivatives (14 and 15)(alkyl: methyl, ethyl, n-propyl, n-pentyl, n-octyl) were synthesized and evaluated as aromatase inhibitors. Androst-4-en-17-ones having an oxygen function (hydroxy, acetoxy, or methoxy group) at C-6 alpha and C-6 beta (4 and 5) were also tested for their abilities to inhibit aromatase. All of the steroids studied inhibited human placental aromatase in a competitive manner. The inhibitory activities of the 6 alpha- and 6 beta-methyl-17-keto steroids 18a and 19a (Ki = 3.1 and 5.3 nM, respectively) as well as the 6 beta- alcohol 5a (Ki = 6.0 nM) were high, and their apparent Ki values were lower than that of the parent 6-unsubstituted 3-deoxy steroid 1 (Ki = 6.8 nM). Elongation of the methyl group decreased affinity for aromatase in relation to carbon number of the alkyl chain in each series, in which the 6 alpha- alkyl steroids 18 essentially had higher affinity for the enzyme than the corresponding 6 beta- isomers 19. The inhibitory activities of the 17 beta-hydroxy analogs 14 and 15 were less potent than those of the corresponding 17-keto steroids. The 6 alpha-ethyl compound 18b, the 6 alpha-oxygenated derivatives 4, and the 6 beta-acetoxy and 6 beta-methoxy analogs 5b and 5c were powerful inhibitors (Ki = 12-24 nM). The methyl steroids (18a and 19a) produced "type I" difference spectra upon interaction with aromatase. These results along with molecular modeling with the PM3 method suggest that compounds 18a and 19a may produce a thermodynamically stable enzyme-inhibitor complex in the hydrophobic binding pocket with a limited accessible volume. A carbonyl group at C-17 of the 6-alkylandrost-4-enes is essential for the tight binding. Moreover, the binding pocket also tolerates a polar hydroxy group at the 6 beta-position rather than at the 6 alpha-position.

The role of perceptual and structural similarity in cross-adaptation

Cross-adaptation, the decrease in sensitivity to one odorant following exposure to a different odorant, is affected by odorant similarity, both perceptual and structural, but the precise relationship is obscure. The present series of studies was designed to explore various aspects of perceptual and structural similarity as they relate to cross-adaptation. In Experiment 1, cross-adaptation was assessed between androstenone and five odorants that share a common urinous note with androstenone, but retain unique perceptual characteristics; only the compound judged most perceptually similar to androstenone cross-adapted it. In Experiment 2, odorants both perceptually and structurally similar (androstenone and androstanone) displayed significant, mutual cross-adaptation. Furthermore, magnitude estimates for androstanone were significantly reduced following exposure to 3-methylidene-5 alpha-androstane (3M5A), a structurally similar, perceptually odorless compound. This finding appears to be the first demonstration that an odorless compound can affect, via cross-adaptation, the perception of an odorous compound. Finally, in Experiment 3, significant, asymmetric cross-adaptation was observed between compounds that are perceptually and structurally dissimilar (4-cyclohexylcyclohexanone [4-CHCH] and androstenone). These findings indicate that the role of similarity in cross-adaptation is difficult to quantify and emphasize the numerous odorant characteristics that can affect cross-adaptation.

Vinyl fluoride as a mimic of the "intermediate' enol form in the 5 alpha-reductase transformation: synthesis and in vitro activity of (N-1',1'-dimethylethyl)-3-haloandrost-3,5-diene-17 beta-carboxamides

(N-1',1'-Dimethylethyl)-3-haloandrost-3,5-diene-17 beta-carboxamides (9-11) and the methyl ester 8 were prepared from 3-chloro/bromoandrost-3,5-diene-17 beta-carboxylic chloride/bromide (6/7), which were obtained from pregnenolone. In comparison with finasteride and 4-MA, compounds 8-11 showed very weak inhibitory activity ( < or = 10% inhibition) on human type I 5 alpha-reductase (transfected 293 cells) at 100 and 1000 nM concentrations. Against the type II enzyme, chloro compounds 8 and 9, and bromo 10 had no effect at 100 nM concentration, however, they were weak inhibitors of the type II (6.0% < inhibition < 30%) at a higher concentration. The best activity (IC50 = 480 nM) was observed with the 3-vinyl fluoride analogue 11.

Steroidal alkenylphosphonates via palladium-catalyzed coupling reactions

The palladium-catalyzed coupling of various 17-iodo-delta 16 steroids (17-iodo-androst-16-ene, 17-iodo-4-methyl-4-aza-androst-16-en-3-one, and 17-iodo-4-aza-androst-16-en-3-one) with dialkyl phosphites (dimethyl phosphite, diethyl phosphite, and diisopropyl phosphite) was examined in detail. The only successful condition for homogeneous coupling involved carrying out the reaction in the absence of any solvents. A large excess of dialkyl phosphite was used, which means that the phosphite itself acted as a solvent. Eight new androst-16-ene derivatives with phosphonate groups at C-17 were synthesized and characterized. These steroids are of pharmacological interest as potential 5 alpha-reductase inhibitors. Under the same conditions, methylation of lactam NH was observed using dimethyl phosphite.

Homogeneous catalytic dehalodimerization of 17-iodo-delta 16 steroids

17-Iodo-delta 16 steroids undergo selective dimerization and carbonylative dimerization in the presence of palladium catalysts in dimethylformamide which result in 16-17'-coupled dienes and 17-carboxylic anhydrides, respectively. Moderate to good yields have been obtained for both types of dimers.

Palladium-catalyzed homogeneous coupling reactions of steroids with organostannanes

Direct and carbonylative coupling reactions of various steroid derivatives possessing iodo- and bromo-alkenyl moiety (17-iodo-androst-16-ene, 1, 17-bromoandrost-2,16-diene, 2, 17-iodo-4-aza-4-methylandrost-16-en-3-one, 3, 17-iodo-4-azaandrost-16-en-3-one, 4) with vinyltributylstannane and ethynyltributylstannane were carried out in the presence of various palladium catalysts. While carbonylation took place only with vinyltributylstannane, 17-vinyl-, and 17-ethynyl-delta 16 steroids were produced via direct coupling with vinyltributylstannane and ethynyltributylstannane, respectively. Activities of some catalysts based on Pd(0) and Pd(II) precursors were compared, and Pd(PPh3)4 was found to be superior to other complexes in most cases. In the coupling of 17-iodoandrost-16-ene with organostannanes Pd2(dba)3 + 8 AsPh3 in situ catalyst was found to be even more effective.

Direct and carbonylative vinylation of steroidal triflates in the presence of homogeneous palladium catalysts

The palladium-catalyzed vinylation of several steriod 2-enyl- and 3,5-dienyl-3 triflates and estrone-3-triflate was systematically examined using vinyltributylstannane as a vinylating agent. In carbon monoxide atmosphere the insertion of a CO molecule took place and unsaturated ketones were obtained. In this way new steroid derivatives containing unsaturated side chain were produced, which can serve as starting material for further functionalization of the steroid skeleton.