Radiolabeled 5-iodo-3'-O-(17beta-succinyl-5alpha-androstan-3-one)-2'-deoxyuridine and its 5'-monophosphate for imaging and therapy of androgen receptor-positive cancers: synthesis and biological evaluation.

High levels of androgen receptor (AR) are often indicative of recurrent, advanced, or metastatic cancers. These conditions are also characterized by a high proliferative fraction. 5-Radioiodo-3'-O-(17beta-succinyl-5alpha-androstan-3-one)-2'-deoxyuridine 8 and 5-radioiodo-3'-O-(17beta-succinyl-5alpha-androstan-3-one)-2'-deoxyuridin-5'-yl monophosphate 13 target AR. They are also degraded intracellularly to 5-radioiodo-2'-deoxyuridine 1 and its monophosphate 20, respectively, which can participate in the DNA synthesis. Both drugs were prepared at the no-carrier-added level. Precursors and methods are readily adaptable to radiolabeling with various radiohalides suitable for SPECT and PET imaging, as well as endoradiotherapy. In vitro and in vivo studies confirm the AR-dependent interactions. Both drugs bind to sex hormone binding globulin. This binding significantly improves their stability in serum. Biodistribution and imaging studies show preferential uptake and retention of 8 and 13 in ip xenografts of human ovarian adenocarcinoma cells NIH:OVCAR-3, which overexpress AR. When these drugs are administered at therapeutic dose levels, a significant tumor growth arrest is observed.

New steroidal derivatives synthesized using 3beta-hydroxyandrosten-17-one as starting material.

In this study, we synthesized some new substituted steroidal derivatives using 3beta-hydroxyandrosten-17-one (dehydroepiandrosterone) as starting material. The synthesized steroidal derivatives 1-11 were evaluated for their androgenic-anabolic activities compared to testosterone as positive control. Details of the synthesis, spectroscopic data and toxicity (LD50) of synthesized compounds are reported.

Novel 17beta-substituted conformationally constrained neurosteroids that modulate GABA A receptors.

The goal of this study was to develop a series of allopregnanolone analogues substituted by conformationally constrained 17beta side chains to obtain additional information about the structure-activity relationship of 5alpha-reduced steroids to modulate GABA(A) receptors. Specifically, we introduced alkynyl-substituted 17beta side chains in which the triple bond is either directly attached to the 17beta-position or to the 21-position of the steroid skeleton. Furthermore, we investigated the effects of C22 and C20 modification. The in vitro binding affinity for the GABA(A) receptor of the new analogues was measured by allosteric displacement of the specific binding of [(3)H]4'-ethynyl-4-n-propyl-bicycloorthobenzoate (EBOB) to GABA(A) receptors on synaptosomal membranes of rat cerebellum. An allosteric binding model that has been successfully applied to ionotropic glycine receptors was employed. The most active derivative is (20R)-17beta-(1-hydroxy-2,3-butadienyl)-5alpha-androstane-3-ol (20), which possesses low nanomolar potency to modulate cerebellar GABA(A) receptors and is 71 times more active than the control compound allopregnanolone. Theoretical conformational analysis was employed in an attempt to correlate the in vitro results with the active conformations of the most potent of the new analogues.

Modified gamma-cyclodextrins and their rocuronium complexes.

A series of per-6-substituted cyclodextrin derivatives was synthesized as synthetic host molecules for rocuronium, a steroidal muscle relaxant. By forming host-guest complexes with rocuronium, these cyclodextrin derivatives reverse the muscle relaxation induced by rocuronium in vitro and in vivo. The isothermal microcalorimetry data are consistent with the biological data supporting the encapsulation mechanism of action. Binary and biphasic complexes are reported with NMR experiments clearly showing free and bound rocuronium. [structure: see text]

Synthesis and optimization of a new family of type 3 17 beta-hydroxysteroid dehydrogenase inhibitors by parallel liquid-phase chemistry.

Type 3 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) transforms 4-androstene-3,17-dione (Delta(4)-dione) into the androgen testosterone. To produce potent inhibitors of this key steroidogenic enzyme, we performed parallel liquid-phase synthesis of 3beta-substituted androsterone (ADT) libraries (A-D) in good yields and average high-performance liquid chromatography (HPLC) purities of 92-94%. The first library (A) of 3 beta-amidomethyl-ADT derivatives (168 members), including two levels of molecular diversity on the amide (R(1) and R(2)), was synthesized with a parallel liquid-phase method (method I) in less time than with the classic chemistry method. The screening of library A revealed that relatively small hydrophobic chains at R(1) (5-8 carbons) and small hydrophobic substituents at R(2) (1-4 carbons) provided the most potent inhibitors. In accordance with these inhibition results, a second library (B) of 3 beta-amidomethyl-ADT derivatives (56 members) was generated in a very short time using an improved method based on scavenger resins and liquid-phase parallel chemistry. Library B produced more potent inhibitors than library A and provided useful structure-activity relationships that directed the design of a third library (C) of 49 members. Once again, very potent inhibitors were identified from library C and 3 beta-[(N-adamantylmethyl-N-butanoyl)aminomethyl]-3 alpha-hydroxy-5 alpha-androstan-17-one (C-7-3) was identified as the most potent inhibitor of the three libraries with an inhibitory activity (IC(50) = 35 nM) 18-fold higher than that of the natural substrate of the enzyme, Delta(4)-dione, (IC(50) = 650 nM) used itself as inhibitor. Finally, we designed a library (D) of 3-carbamate-ADT derivatives (25 members) using the efficient parallel liquid-phase method III, which allowed the synthesis of more rigid molecules with two levels of molecular diversity (R(1)/R(2) and R(3)) in the local area occupied by the adamantane group of C-7-3. Interestingly, one of the most potent inhibitors of library D, the 3R-spiro-[3'-[3' '-N-morpholino-2' '-(3' "-cyclopentyl-propionyloxy)propyl]-2'-oxo-oxazolidin-5'-yl]-5 alpha-androstan-17-one (D-5-4), showed an inhibitory activity on type 3 17 beta-HSD similar to that of compound C-7-3, while exhibiting a nonandrogenic profile.

17 alpha-O-(aminoalkyl)oxime derivatives of 3 beta,14 beta-dihydroxy-5 beta-androstane and 3 beta-hydroxy-14-oxoseco-D-5 beta-androstane as inhibitors of Na(+),K(+)-ATPase at the digitalis receptor.

The synthesis and binding affinities to the digitalis Na(+),K(+)-ATPase receptor of a series of 3 beta,14 beta-dihydroxy-5 beta-androstane and 3 beta-hydroxy-14-oxoseco-D-5 beta-androstane derivatives bearing a 17 alpha-(aminoalkoxy)imino chain are reported; some derivatives were also studied for their inotropic activity. Our recently proposed model of interaction of molecules with the digitalis receptor was used to design these compounds. On that basis, the possibility to design novel potent inhibitors of Na(+),K(+)-ATPase without being constrained by the stereochemistry of the classical digitalis skeleton in the D-ring region was predicted. The binding affinities of the most potent compounds in the two series, (EZ)-17 alpha-[2-[(2-aminoethoxy)imino]ethyl]-5 beta-androstane-3 beta,14 beta-diol (6f) and (EZ)-3 beta-hydroxy-17 alpha-[2-[(2-aminoethoxy)imino]ethyl]-14,15-seco-5 beta-androstan-14-one (24c) are higher than that of the potent natural compound digitoxigenin, despite the unusual alpha-exit of the substituent in position 17 of 6f or the disruption of the D-ring in 24c. These results further support the validity of our recently proposed model of binding at the digitalis receptor. Results of the inotropic tests on guinea pig atrium deserve further investigation on the pharmacological profile of these derivatives.

Neighboring group participation. Part 14. The preparation of the four stereoisomers of 16-hydroxymethyl-5alpha-androstane-3beta,17-diol.

16alpha-Hydroxymethyl-5alpha-androstane-3beta,17beta-diol and 16beta-hydroxymethyl-5alpha-androstane-3beta,17beta-diol, were obtained from reduction of 16-acetoxymethylene-5alpha-androstan-17-one. The corresponding 16alpha,17alpha- and 16beta,17alpha-hydroxymethyl isomers were obtained by neighboring group participation of the 16- and 17-acetates, respectively. The reactions involving carbocation formation also led to ring D rearrangement products.

Synthesis of (5alpha)-17-azaandrostan-3-ols and (5alpha)-17-aza-D-homoandrostan-3-ols and their N-acylated derivatives.

Two groups of N-acylated D-azasteroids (4 and 5) were synthesized to explore structure-activity relationships for steroid modulation of GABA(A) receptor function. The target compounds were prepared conveniently from (5alpha)-3-hydroxyandrostan-17-ones (6 and 7) via the intermediate (5alpha)-17-aza-D-homoandrostan-3-ols (14 and 15) or (5alpha)-17-azaandrostan-3-ols (18 and 19) precursors in high overall yields. A Beckmann rearrangement and a Hofmann rearrangement were employed as two key steps in the synthetic sequences.

Conformationally constrained anesthetic steroids that modulate GABA(A) receptors.

Various cyclic ether and other 3 alpha-hydroxyandrostane derivatives bearing a conformationally constrained hydrogen-bonding moiety were prepared. Their anesthetic potency and their binding affinity for GABA(A) receptors, measured by intravenous administration to mice and inhibition of [(35)S]TBPS binding to rat whole brain membranes, were compared with that of known anesthetic 3 alpha-hydroxypregnan-20-ones. Synthetic steroids with similar in vitro and in vivo activities to the endogenous 3 alpha-hydroxypregnan-20-ones all had an ether oxygen on the beta-face of the steroid D-ring. These results suggest that for optimal GABA(A) receptor modulation, the hydrogen bond-accepting substituent should be near perpendicular to the plane of the D-ring on the beta-face of the steroid.

17beta-O-Aminoalkyloximes of 5beta-androstane-3beta,14beta-diol with digitalis-like activity: synthesis, cardiotonic activity, structure-activity relationships, and molecular modeling of the Na(+),K(+)-ATPase receptor.

A series of digitalis-like compounds with a 17-aminoalkoxyiminoalkyl or -alkenyl substituent was synthesized and evaluated for inhibition of Na(+),K(+)-ATPase and for inotropic activity. The highest inhibition was found with compounds having the substituent in configuration 17beta and the amino group at a distance of 6 or 7 bonds from C(17) of the digitoxigenin skeleton. The presence of the oxime function strengthens the interaction with the receptor, more if alpha,beta-unsaturated, thus mimicking the electronic situation of the unsaturated lactone in natural digitalis compounds. The most active compounds showed Na(+),K(+)-ATPase inhibitory potencies (IC(50)) 17-25 times higher than the standards digitoxigenin and digoxin and 3-11 times higher inotropic potencies (EC(50)) in isolated guinea pig left atria. These features are supported by a molecular model suggesting the possible interactions of the groups described above with particular amino acid residues in the H1-H2 domains of Na(+),K(+)-ATPase. Some interactions are the classical ones already described in the literature; a new, very strong interaction of the basic group with the Cys138 was found and adds new possibilities to design compounds interacting with this region of the receptor. The most interesting compounds were also studied in vivo in the anesthetized guinea pig for evaluating their inotropic effect versus the lethal dose. Compounds 9 and 12 showed a slightly higher safety ratio than digoxin and deserve further evaluation.

The 16,17-double bond is needed for irreversible inhibition of human cytochrome p45017alpha by abiraterone (17-(3-pyridyl)androsta-5, 16-dien-3beta-ol) and related steroidal inhibitors.

Abiraterone (17-(3-pyridyl)androsta-5,16-dien-3beta-ol, 1) is a potent inhibitor (IC50 4 nM for hydroxylase) of human cytochrome P45017alpha. To assist in studies of the role of the 16,17-double bond in its mechanism of action, the novel 17alpha-(4-pyridyl)androst-5-en-3beta-ol (5) and 17beta-(3-pyridyl)-16,17alpha-epoxy-5alpha-androst-3beta-ol (6) were synthesized. 3beta-Acetoxyetienic acid was converted in three steps into 5 via photolysis of the thiohydroxamic ester 8. Oxidation of an appropriate 16,17-unsaturated precursor (21) with CrO3-pyridine afforded the acetate (23) of 6. Inhibition of the enzyme by 1, the similarly potent 5,6-reduced analogue 19 (IC50 5 nM), and the 4, 16-dien-3-one 26 (IC50 3 nM) and by the less potent (IC50 13 nM) 3,5, 16-triene 25 is slow to occur but is enhanced by preincubation of the inhibitor with the enzyme. Inhibition following preincubation with these compounds is not lessened by dialysis for 24 h, implying irreversible binding to the enzyme. In contrast under these conditions the still potent (IC50 27 nM) 17alpha-(4-pyridyl)androst-5-en-3beta-ol (5) showed partial reversal after 5 h of dialysis and complete reversal of inhibition after 24 h. This behavior was also shown by the less potent 16,17-reduced 3-pyridyl compounds 3 and 24. Further, in contrast to the compounds (1, 19, 25, 26) with the 16,17-double bond, the inhibition of the enzymic reaction was not enhanced by preincubation either with 5 or with the 17beta-pyridyl analogues 3, 4, and 24 which also lack this structural feature. The results show that the 16,17-double bond is necessary for irreversible binding of these pyridyl steroids to cytochrome P45017alpha. However oxidation to an epoxide is probably not involved since epoxide 6 was only a moderately potent inhibitor (IC50 260 nM).

Synthesis and quantitative structure-activity relationship of 17 beta-(hydrazonomethyl)-5 beta-androstane-3 beta,14 beta-diol derivatives that bind to Na+,K(+)-ATPase receptor.

A series of 17 beta-(hydrazonomethyl)-5 beta-androstane-3, beta,14 beta-diol derivatives was synthesized and evaluated in the displacement of [3H]ouabain binding from Na+,K(+)-ATPase. The data were explored with multiple linear regression and partial least-squares to find possible quantitatives structure-activity relationships. Good correlations were found between binding to the receptor and van der Waals volumes or molar refractivities of the 17 beta-hydrazonomethyl substituents and pKa values of the compounds. Equivalent results were obtained using the proton affinity (calculated using MOPAC) of the hydrazone residues instead of experimental pKa. As basicity or related electronic factors of the substituents explain a significant portion of the observed changes in the activity, an ion-pair interaction between a carboxylate residue of the enzyme and the protonated 17 beta-hydrazonomethyl group, as postulated by Thomas, plays an important role in the interaction of the ligand to the Na+,K(+)-ATPase receptor.

Aromatase inhibitors: effect of ring A and ring B unsaturation on aromatase inhibition by 4-thiosubstituted derivatives of 4-androstene-3,17-dione.

The synthesis and biological evaluation of 4-thiosubstituted derivatives of 1,4-androstadienedione, 4,6-androstadienedione, and 1,4,6-androstatrienedione as inhibitors of aromatase are described. Inhibitory activity of synthesized compounds was assessed using a human placental microsomal preparation as the enzyme source and [1 beta-3H]androstenedione as substrate. Under initial velocity assay conditions of low product formation, the inhibitors demonstrated potent inhibition of aromatase, with apparent Kis ranging from 9.8 to 137 nM and with Km for androstenedione being 38 nM. However, unlike other 1,4-androstadienediones and 1,4,6-androstatrienediones in which time-dependent inactivation was observed, the 4-thiosubstituted analogs were found to be competitive inhibitors and did not produce any time-dependent inactivation of aromatase.

Synthesis and biological activity of bile acid-derived HMG-CoA reductase inhibitors. The role of 21-methyl in recognition of HMG-CoA reductase and the ileal bile acid transport system.

To increase hepatoselectivity of HMG-CoA reductase inhibitors by using the specific bile acid transport systems, deoxycholic acid-derived inhibitors 9 and 11 have been synthesized, on the basis of the concept of combining in one molecule structural requirements for specific inhibition of the HMG-CoA reductase and specific recognition by the ileal bile acid transport system. The 1-methyl-3-carboxylpropyl subunit of deoxycholic acid was replaced by the 3,5-dihydroxyheptanoic acid lactone of lovastatin, and position 12-OH was esterified with 2-methylbutyric acid. Compounds 9 and 11 were evaluated for their inhibitory activity on rat liver HMG-CoA reductase, cholesterol biosynthesis in HEP G2 cells, and [3H]taurocholate uptake in rabbit brush border membrane vesicles and compared with methyl derivatives 8 and 10. The steroidal 21-CH3 group affects both activity on HMG-CoA reductase and recognition by the ileal bile acid transport system.

Studies on anabolic steroids. 10. Synthesis and identification of acidic urinary metabolites of oxymetholone in a human.

Two major unconjugated acidic metabolites of oxymetholone (17 beta-hydroxy-2-hydroxymethylene-17 alpha-methyl-5 alpha-androstan-3-one, 1), namely, 17 beta-hydroxy-17 alpha-methyl-2,3-seco-5 alpha-androstane-2,3-dioic acid (2) and 3 alpha,17 beta-dihydroxy-17 alpha-methyl-5 alpha-androstane-2 beta-carboxylic acid (6a), were detected by gas chromatography/mass spectrometry in urine samples collected after oral administration of 1 to a human volunteer. Reference steroid 2 was synthesized and identified. The identification of urinary metabolite 6a was based on the synthesis of its stereoisomers and the isomerization of the methyl ester 6b to its 2-epimer, 3 alpha,17 beta-dihydroxy-17 alpha-methyl-5 alpha-androstane-2 alpha-carboxylic acid methyl ester (9b). The mechanisms accounting for the formation of these acidic metabolites are discussed.

Peptidyl aminosteroids as potential new antiarrhythmic agents.

The synthesis of peptidyl derivatives of the aminosteroid, amafalone (Am), is described. Six analogs were synthesized: the hydrochloride salts of Gly-Am (2) Ala-Gly-Am (3), D-Ala-Gly-Am (4), Pro-Am (6), Pro-Pro-Am (7), and D-Ala-Pro-Am (8). The peptide bonds were formed by the polymeric reagent method using polymeric hydroxybenzotriazole as the activating polymer. Peptidyl aminosteroids 2, 6, 7, and 8, when administered to rats intravenously, had protective antiarrhythmic effects similar to those of amafalone. By the oral route, less marked protection, in comparison to amafalone, was observed with 6, while 7 and 8 were disappointingly inactive.

Synthesis of 5 alpha-androstane-3 alpha,17 beta-diol 3- and 17-glucuronides.

The glucuronidation of 5 alpha-androstane-3 alpha,17 beta-diol (3 alpha-diol) was carried out by three different methods: The Koenigs-Knorr reaction using methyl-2,3,4-tri-O-acetyl-1 alpha-bromo-1-deoxy-beta-D-glucuronate, by employing methyl-2,3,4-tri-O-acetyl-1-O-(trichloroacetimidoyl)-alpha-D-gl ucopyranuronate (imidate procedure), and by the reaction of 2,3,4-tri-O-acetyl-alpha-D-glucopyranuronate catalyzed by trimethylsilyl trifluoromethanesulfonate (triflate method). The Koenigs-Knorr method gave the beta-anomers of both the 3- and 17-glucuronides. The imidate procedure also resulted in the beta-anomers of the 3- and 17-glucuronides, but in lower yield. The triflate method, however, yielded only the alpha-anomers of the 3- and 17-glucuronides. The structural assignments of these compounds were made from NMR spectral data obtained with a 500 mHz instrument.

Synthesis of 5 alpha-androstane-3 alpha, 16 alpha, 17 beta-triol from 3 beta-hydroxy-5-androsten-17-one.

5 alpha-Androstane-3 alpha, 16 alpha, 17 beta-triol was synthesized from 3 beta-hydroxy-5-androsten-17-one. The procedure involved catalytic hydrogenation of 3 beta-hydroxy-5-androsten-17-one to 3 beta-hydroxy-5 alpha-androstan-17-one. This was followed by conversion of the 3 beta-hydroxy group to 3 alpha-benzoyloxy group by the Mitsunobu reaction. Further treatment with isopropenyl acetate yielded 5 alpha-androsten-16-ene-3 alpha, 17-diol 3-benzoate 17-acetate. This was then converted to 3 alpha, 17-dihydroxy-5 alpha-androstan-16-one 3-benzoate 17-acetate via the unstable epoxide intermediate after treatment with m-cloroperoxybenzoic acid. LiA1H4 reduction of this compound formed 5 alpha-androstane-3 alpha, 16 alpha, 17 beta-triol. 1H and 13C NMR of various steroids are presented to confirm the structure of this compound.