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A series of new 17-cyanopyridine derivatives of pregnenolone have been synthesized, and their anti-proliferative activities against different human cancer cell lines were tested. The extensive structure-activity relationship (SAR) data suggested that the introduction of 2-amino-4-aryl-3-cyanopyridine to the D ring of pregnenolone may increase the anti-cancer activity. Among the products, the most potent compound 4j exhibited good growth inhibition against all the tested cells especially for PC- 3 cells with an IC 50 value of 2.0 μM. Further mechanistic studies showed that 4j inhibited the formation of cell colonies and migration, increased the level of reactive oxygen species (ROS) in PC-3 cells in a concentration-dependent manner, and induced necroptosis through the phosphorylation of receptor interacting protein 1/3 (P-RIP1/3) and phosphorylation of mixed lineage kinase domain-like protein (P-MLKL) pathway. The 17-pregnenolone cyanopyridine derivatives hold promising potential as anti-proliferative agents, and the most potent compound could be used as a starting point for the development of new steroidal heterocycles with improved anticancer potency and selectivity., (Copyright © 2021. Published by Elsevier Inc.)

Steroids are polycyclic compounds and are broadly exist in the natural world and display various biological activities. Many steroidal compounds have been used as traditional medicines, for example, antibacterial and few as hormone like medication. The introduction of heterocycle or heteroatom in the steroidal moiety has a significant biological impact. These derivatives have widespread biological activities such as anticancer, anti-inflammatory, anti-ulcer and antimicrobial. The present article is a brief review of the recent development of synthesis and biological activities of pregnenolone derivatives., (Copyright © 2021 Elsevier Inc. All rights reserved.)

In current study, we synthesized chalcone derivatives (13a-c) via base-catalyzed Claisen-Schmidt condensation reaction. We further treated diamino compounds with synthesized chalcones to produce 3,4-dihydropyrimidin-2(1H)-one (18a-c), 3,4-dihydropyrimidin-2(1H)-thione (19a-c) and 2-aminopyrimidine (20a-c) derivatives of pregnenolone by cyclization reaction. Cell viability test of synthesized steroidal chalcones and their pyrimidine and thiopyrimidine derivatives against human breast (MCF-7), human lung (A549) and human prostate (PC-3) cancer cell lines was performed using (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), assay. Compounds were further evaluated for their inhibition potential against recombinant human DHFR (rhDHFR). All compounds showed activity from low micromolar to submicromolar range. Compound 20b with IC 50 value of 180 nM emerged as most potent compound against rhDHFR. Interaction of the newly synthesized pregnenolone derivatives with hDHFR and estrogen receptor alpha (ERα) were also explored via docking simulations. The overall results of hDHFR inhibition have shown that these analogues can be further optimized and developed as potent anticancer agents., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Aromatase, a cytochrome P450 hemoprotein that is responsible for estrogen biosynthesis by conversion of androgens into estrogens, has been an attractive target in the treatment of hormonedependent breast cancer. Design of new steroidal aromatase inhibitors becomes imperative., Objective: Synthesis and biological evaluation of two classes of structurally and functionally diverse D-ring pregnenolone pyrazoles as type I aromatase inhibitors and antiproliferative agents., Methods: Pregnenolone (1) was converted to 3β-hydroxy-21-hydroxymethylidenepregn-5-en-20-one (2), which upon cyclization with phenylhydrazine generated regioisomeric pairs of pyrazoles 4 and 5. Further, Knoevenagel condensation of pregnenolone (1) with 3-oxo-3-phenylpropanenitrile (6) produced 2-benzoyl-3-(3b-hydroxyandrostan- 5-ene-20-ylidene)-but-2-enenitrile (7), which upon cyclization with hydrazine or phenylhydrazine generated the pyrazoles 8 and 9. All new steroidal derivatives were tested for their aromatase inhibition activity using Dibenzylfluorescein (DBF) based fluorescence assay developed by Stresser et al. Antiproliferative activities were measured using Sulforhodamine B assay. The activities were promising and there was a coherence between aromatase inhibitory and antiproliferative activities., Results: The study reveals the immense potential of pregnenolone pyrazoles as aromatase inhibitors for the treatment of breast cancer. Molecular docking studies proved efficient binding of the new steroidal analogs on human placental aromatase., Conclusion: In the overall study, most of the compounds exhibited potential activity for the treatment of hormone dependent breast cancer. Compounds 4c and 4d were found to be the most promising pharmacons. Furthermore, compounds 4c and 4d were applied for their molecular docking study on human placental aromatase to predict their possible binding modes with the enzyme. These studies revealed that such molecules have high scope and potential for further investigation towards the treatment of estrogen dependent breast cancer., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

20-hydroxycholesterol is a signaling oxysterol with immunomodulating functions and, thus, structural analogues with reporter capabilities could be useful for studying and modulating the cellular processes concerned. We have synthesized three new 20-hydroxycholesterol-like pregn-5-en-3β-ol derivatives with fluorescent 7-nitrobenzofurazan (NBD) or Raman-sensitive alkyne labels in their side-chains. In silico computations demonstrated the compounds possess good membrane permeability and can bind within active sites of known 20-hydroxycholesterol targets (e.g. Smoothened and yeast Osh4) and some other sterol-binding proteins (human LXRβ and STARD1; yeast START-kins Lam4S2 and Lam2S2). Having found good predicted membrane permeability and binding to some yeast proteins, we tested the compounds on microorganisms. Fluorescent microscopy indicated the uptake of the steroids by both Saccharomyces cerevisiae and Yarrowia lipolytica, whereas only S. cerevisiae demonstrated conversion of the compounds into 3-O-acetates, likely because 3-O-acetyltransferase Atf2p is present only in its genome. The new compounds provide new options to study the uptake, intracellular distribution and metabolism of sterols in yeast cells as well as might be used as ligands for sterol-binding proteins., Competing Interests: Declaration of Competing Interest Authors claim no conflict of interests., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Four series of pregnenolone derivatives having one or two α,β-unsaturated carbonyls and an ester moiety at C-21 or C-3 were synthetized to compare their cytotoxicity effect. The final compounds were evaluated on three human cancer cell lines: PC-3 (prostate cancer), MCF-7 (breast cancer), SKLU-1 (lung cancer) and a noncancerous cell line HGF (human gingival fibroblast). Two steroids with a 4-fluorinated benzoic acid ester at C-21 were the most active against lung cancer cell line with IC 50 of 13.1 ± 1.2 and 12.8 ± 0.5 μM and showed a low percentage of cytotoxicity for noncancerous cells (27.63 ± 2.3 and 18.39 ± 1.2% in the screening at 50 μM)., (Copyright © 2018. Published by Elsevier Inc.)

Background: The potential of steroids for development into lead pharmacological molecules lies in the regulation of a variety of biological processes by these molecules and also because of these being a fundamental class of signaling molecules. Steroid based scaffolds have been extensively used as active pharmaceutical agents for the treatment of various diseases including the deadly disease of cancer which despite the recent advances in the early diagnosis, prevention and therapy, remains a clinical challenge affecting millions of people world over and is one of the leading causes of death. It thus warrants the development of new drugs against this dreadful disease through exploitation of emerging molecularly defined targets., Methods: The present study explores the effect of novel steroidal pyrazolines as presumed inhibitors of 5α- reductase (5AR) and 17α-hydroxylase-C 17,20 -lyase as a target for treatment of prostate cancer. A series of 1,5- diaryl pyrazoline pregnenolones were synthesized and screened for 5α-reductase inhibitory activities. Synthesis of the analogs is multistep and proceeds in good overall yields. The key step in the synthesis of 1,5- disubstituted pyrazolinyl pregnenolones is the heterocyclization of bezylidine derivatives (3) in presence of phenylhydrazines (4) through the initial formation of the phenylhydrazones, which undergo concomitant cyclization to generate the stable pyrazoline derivatives., Results: All the synthesised D-ring 1,5-disubstituted pyrazolinyl pregnenolone derivatives (5a-l) were screened for prostate cancer cell inhibitory, 5α-reductase and 17α-hydroxylase-C 17,20 -lyase inhibitory activity. Amongst all the compounds screened for their 5α-reductase inhibitory activities, compound 5c, 5e, 5g and 5l were found to be the most active. Further, compounds 5g and 5h were found to have moderate 17α-hydroxylase-C 17,20 -lyase inhibitory activities., Conclusion: A series of D-ring 1,5-disubstituted pyrazolinyl pregnenolone derivatives (5a-l) were synthesized and screened for their prostate cancer cell inhibitory, 5a-reductase and 17α-hydroxylase-C17,20-lyase inhibitory activity. Amongst all the compounds screened for their 5α-reductase inhibitory activities, compound 5c, 5e, 5g and 5l were found to be the most active whereas compounds 5g and 5h were found to have moderate 17α- hydroxylase-C 17,20 -lyase inhibitory activities., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Aza-Michael addition of 16-dehydropregnenolone was studied in the presence of a basic ionic liquid, [DBU][OAc] as catalyst and solvent. The reaction was carried out using different primary and secondary amines as N-nucleophiles. The products were obtained in moderate to good yields and were characterized by 1 H and 13 C NMR, MS and IR. The ionic liquid was found to be an efficient and recyclable catalyst that was reused five times. The products were investigated for the inhibition of in vitro C 17,20 -lyase activity and displayed moderate inhibitory effect., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Testosterone (T) plays a crucial role in prostate growth. In androgen-dependent tissues T is reduced to dihydrotestosterone (DHT) because of the presence of the 5α-reductase enzyme. This androgen is more active than T, since it has a higher affinity for the androgen receptor (AR). When this mechanism is altered, androgen-dependent diseases, including prostate cancer, could result. The aim of this study was to synthesize several 16-dehydropregnenolone acetate derivatives containing a triazole ring at C-21 and a linear or alicyclic ester moiety at C-3 of the steroidal skeleton. These steroids were designed as potential inhibitors of the activity of both types (1 and 2) of 5α-reductase. The cytotoxic activity of these compounds was also evaluated on a panel of PC-3, MCF7, and SK-LU-1 human cancer cell lines. The results from this study showed that with the exception of steroids 20-oxo-21-(1H-1,2,4-triazole-1-yl)pregna-5,16-dien-3β-yl-propionate and 20-oxo-21-(1H-1,2,4-triazole-1-yl)pregna-5,16-dien-3β-yl-pentanoate, the compounds exhibit a lower inhibitory activity for both isoenzymes of 5α-reductase than finasteride. Furthermore the 3β-hydroxy-21-(1H-1,2,4-triazole-1-yl)pregna-5,16-dien-20-one and 20-oxo-21-(1H-1,2,4-triazole-1-yl)pregna-5,16-dien-3β-yl-acetate derivatives display 80% cytotoxic activity on the SK-LU-1 cell line. These results also indicated that the triazole derivatives, which have a hydroxyl or acetoxy group at C-3, could have an anticancer effect, whereas the derivatives with a alicyclic ester group at C-3 do not show biological activity., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

A new class of steroids is being synthesized for its ability to prevent intratumoral androgen production by inhibiting the activity of CYP17 hydroxylase enzyme. The scheme involved the synthesis of chalcone derivative of pregnenolone 5 which was further modified to the corresponding biaryl-chalcone pregnenolone analogs 16-25 using Suzuki-Miyaura cross-coupling reaction. The synthesized compounds were tested for activity using human CYP17α hydroxylase expressed in Escherichia coli. Compounds 21 was the most active inhibitor in this series, with IC50 values of 0.61μM and selectivity profile of 88.7% inhibition of hydroxylase enzyme. Molecular docking study of 21 was performed and showed the hydrogen bonds and hydrophobic interaction with the amino acid residues of the active site of CYP17., (Copyright © 2015 Elsevier Inc. All rights reserved.)

A new series of 17-(N-(arylimino)-5-pregnen-3β-ol derivatives 19-32 as well as carboxylate and acrylate analogues of pregnenolone 37-40 were synthesized and evaluated for their inhibitory activity against human CYP17 hydroxylase expressed in Escherichia coli. Compounds 32 and 37 were the most potent analogues in this series, showing inhibition activity with IC50 = 2.11 and 1.29 μM, respectively. However, the analogue 37 revealed a better selectivity profile (83.21% inhibition of hydroxylase), which is a leading candidate for further development. Molecular docking study of 37 showed binding with the amino acid residues of CYP17 through hydrogen bonds and hydrophobic interaction., (Copyright © 2015. Published by Elsevier Inc.)

A series of novel C21-alkynylaryl derivatives of pregnenolone were synthesized and screened for anticancer activity against a panel of seven human cancer cell lines (LNCaP, A549, MCF7, HeLa, A431, HepG2, HT29). The data revealed that these compounds can be potential antitumour agents against the specific cell models. Compound 6f bearing a 2-trifluoromethylphenyl group displayed improved cytotoxicity towards all cancer cell lines used. A431 cells were the most sensitive with derivatives 6e-6h bearing electron withdrawing substituents exhibiting high potency with IC50 values ranging between 2.18 and 0.54μM and drastic inhibition of the prosurvival PI3K-Akt/PKB pathway., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

A new series of pregnenonlone analogs were synthesized and evaluated for their inhibitory activity against cytochrome P450 (CYP17 hydroxylase enzyme). In general, the 5-aryl-1,3,4-thiadiazol-2-yl)-imino-pregnenolone derivatives 11-15 were more active than the sulfonate 24-31 and the ester 37-41 analogs. Derivative 12 showed optimal activity in this series, with IC50 values of 2.5 µM compared with the standard abiraterone (IC50  = 0.07 µM). However, the analogs 11 and 25 showed a better selectivity profile (81.5 and 82.7% inhibition of hydroxylase, respectively), which may be a useful lead in CYP17 inhibition studies. Molecular docking studies demonstrated quite similar binding patterns of all new pregnenolone derivatives at the active site of CYP17 through hydrogen bonding and hydrophobic interaction., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The present study reveals the anticancer activity of benzylidine pregnenolones and their oxime derivatives. The synthesis of the analogs of both series is very simple and involves aldol condensation in the first step followed by nucleophillic addition of hydroxylamine across carbonyl in the second step. Quantitative yields of more than 80% are obtained in both the steps. All the compounds were tested for their cytotoxic activities against a panel of six human cancer cell lines. Amongst all the compounds of both the series screened for their cytotoxic activity, compound 3e, 3f and 4e are very potent especially against HCT-15 and MCF-7 cancer cell lines., (Copyright © 2014 Elsevier Inc. All rights reserved.)

The free radical nitric oxide (NO), a main member of neuroinflammatory cytokine and a gaseous molecule produced by activated microglia, has many physiological functions, including neuroinflammation. In the present study, we evaluated the effects of serial 16-dehydropregnenolone-3-acetate derivatives on lipopolysaccharide (LPS)-induced NO production and inducible nitric oxide synthase (iNOS) expression in BV-2 microglial cells. Among the six derivatives tested, the increases in NO production and iNOS expression observed in BV-2 microglial cells after LPS stimulation were significantly inhibited by treatment with 16α, 17α-epoxypregnenolone-20-oxime. Moreover, the inhibitory effect of 16α,17α-epoxypregnenolone-20-oxime on NO production was similar to that of S-methylisothiourea sulfate (SMT), an iNOS inhibitor. Further studies showed that 16α,17α-epoxypregnenolone-20-oxime inhibited c-Jun N-terminal kinase (JNK) phosphorylation but not inhibitor kappa B (IκB)-α degradation. Our data in LPS-stimulated microglia cells suggest that 16α,17α-epoxypregnenolone-20-oxime might be a candidate therapeutic for treatment of NO induced neuroinflammation and could be a novel iNOS inhibitor.

For the first time, [3α-(3) H] 17α-hydroxy pregnenolone (1) was synthesized through a multiple step sequence. The presence of [3β-(3) H] isomer in RP-HPLC purified product was identified by tritium NMR. The [3β-(3) H] isomer was then separated from [3α-(3) H] 17α-hydroxy pregnenolone with chiralPAK AD-H column. [3α-(3) H] pregnenolone (2) was synthesized from commercial available 5-pregnen-3,20-dione in one step with an improved procedure., (Copyright © 2013 John Wiley & Sons, Ltd.)

The reaction of pregnenolone with either 2-aminoprop-1-ene-1,1,3-tricarbonitrile or 3-oxo-3-phenylpropanenitrile gave the Knoevenagel condensation products 3 and 6, respectively. Separation of the E and Z isomeric compounds of 3 and 6 together with their structure elucidation were carried out. Some chemical transformations of the latter products were carried out and the cytotoxicity of the newly obtained products was evaluated against some cancer cell lines and a human normal cell line. The results indicated that compounds 15, 17a, 18 and 20e among the tested compounds showed the highest cytotoxicity against the cancer cell lines., (Copyright © 2013 Elsevier Inc. All rights reserved.)

A novel class of chalconoyl pregnenolones has been prepared via Claisen-Schmidt condensation under microwave activation and solvent free reaction conditions. The compounds were screened for antimicrobial activity against two bacterial strains Bacillus subtilis and Escherichia coli and two fungal strains Aspergillus niger and Candida albicans. Some of the compounds exhibited significant inhibitory activity against the microbial strains. Presence of the α,β-unsaturated carbonyl moiety in the synthesized compounds was found to be essential for the activity as manipulation of the same through epoxidation of the double bond diminished the activity., (Copyright © 2013 Elsevier Inc. All rights reserved.)

A series of 21-arylidenepregnenolone derivatives and their corresponding epoxides were synthesized. The neuroprotective effects of these steroidal compounds against amyloid-β(25-35) (Aβ(25-35))- and hydrogen peroxide (H(2)O(2))-induced neurotoxicity in PC12 cells, and oxygen-glucose deprivation (OGD)-induced neurotoxicity in SH-SY5Y cells were evaluated. The bioassay results indicated that several 3β-pregn-21-benzylidene-20-one derivatives displayed potent in vitro neuroprotective effects in different screening models, for example, compounds 2b, 3a, 3b, and 3s showing significant activities against Aβ(25-35)-induced neurotoxicity in PC12 cells, 2b showing significant activities against H(2)O(2)-induced neurotoxicity in PC12 cells, and 2g, 3b, and 3e showing potent protection against OGD insult. The results suggested that introduction of an arylidene group into steroidal nucleus played an important role in neuroprotective activity, while the formation of epoxy group at C-5,6 could be also important for the neuroprotective activity in some degree. The pharmacological data reported here are helpful for the design of novel steroidal neuroprotective candidates., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Pregnenolone (1) was used as a template to develop new anticancer compounds. Ring-D modification of 1 resulted in the synthesis of benzylidenes 2-17, pyrazolines 18-76, pyrazoles 85-91, hydrazones 77-84, and oximes 92-107 derivatives. The structure of compound 107 was also deduced through single crystal X-ray diffraction studies. The inclusion of furanyl and pyridyl rings to pregnenolone skeleton increases the cytotoxicity of all compounds significantly. Among benzylidene derivatives, only heterocyclic enone 8 (IC50=0.74 μM/mL against HepG2), and 17 (IC50=4.49 μM/mL against HepG2, IC50=5.01 μM/mL against MDA-MB-230 cancer cell line) exhibited a significant activity. The cytotoxicity data of pyrazoline derivatives 18-76 revealed that only furanyl bearing pyrazolines 40, 42-44, 48, and 49 exhibited significant activities. While all (O-carboxymethyl) oximes, hydazones, and pyrazoles derivatives of pregnenolone did not show any significant activity against both the cell lines. Thus the furanyl bearing enone 8 (IC50=0.74 μM/mL against HepG2), and its pyrazoline derivative 48 (IC50=0.91 μM/mL against MDA-MB-230 cancer cell lines) were identified as the most active compounds in all derivatives of pregnenolone., (Copyright © 2011 Elsevier Inc. All rights reserved.)

16-Dehydropregnenolone undergoes a smooth annulation with propan-1-amine and aromatic aldehydes. Several amine derivatives of 16- dehydropregnenolone were synthesized and evaluated as inhibitors of DPP-IV. The structures of compounds were confirmed by (1)H, (13)C, NMR and mass spectral analysis. Among 17 compounds evaluated only five compounds 1, 9, 13, 15 and 16 demonstrated significant inhibition of DPP. This study suggest that introduction of appropriate substituents in the 16-dehydropregnenolone plays an important role in DPP-IV inhibitory activity., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

An efficient and facile synthesis of 17-pyrazolinyl derivatives of pregnenolone and their evaluation as potential anticancer agents against various human cancer cell lines are reported. The scheme involves the transformation of the starting pregnenolone acetate into pregnenolone, conversion of pregnenolone to the corresponding benzylidine derivatives and finally the conversion of this derivative to the stable steroidal 17-pyrazoline. Various compounds 4b, 4c, 4e, 4f, 4h and 4j showed significant cytotoxic activity especially against HT-29, HCT-15, 502713 cell lines., (Copyright 2010 Elsevier Inc. All rights reserved.)

Reaction of 17alpha-bromo-21-iodo-3beta-acetoxypregn-5-en-20-one with ammonia, primary, and secondary amines is simple and convenient method for preparation of [17(20)E]- and [17(20)Z]-pregna-5,17(20)-dien-21-oylamides. Synthesis and characteristics of 12 related amides are presented. Primary testing on cells proliferation indicated differing effects of synthesized compounds on androgen insensitive MCF-7 cells and androgen sensitive LNCaP cells., (Copyright (c) 2010. Published by Elsevier Ltd.)

A series of novel 3beta, 7alpha, 11alpha-trihydroxy-pregn-21-benzylidene-5-en-20-one derivatives were synthesized and characterized by NMR, HRMS. The pregnenolone (1) was first biotransformed by Mucor circinelloides var lusitanicus to 3beta, 7alpha, 11alpha-trihydroxy-pregn-5-en-20-one (3), then 3 was treated with various benzaldehydes to produce 3beta, 7alpha, 11alpha-trihydroxy-pregn-21-benzylidene-5-en-20-one derivatives. These derivatives showed remarkable activity against EC109 cells. The absolute configuration of 3 was also confirmed by signal-crystal X-ray analysis.

The enzyme 5alpha-reductase is responsible for the conversion of testosterone (T) to its more potent androgen dihydrotestosterone (DHT). This steroid had been implicated in androgen-dependent diseases such as: benign prostatic hyperplasia, prostate cancer, acne and androgenic alopecia. The inhibition of 5alpha-reductase enzyme offers a potentially useful treatment for these diseases. In this study, we report the synthesis and pharmacological evaluation of several new 3-substituted pregna-4, 16-diene-6, 20-dione derivatives. These compounds were prepared from the commercially available 16-dehydropregnenolone acetate. The biological activity of the new steroidal derivatives was determined in vivo as well as in vitro experiments. In vivo experiments, the anti-androgenic effect of the steroids was demonstrated by the decrease of the weight of the prostate gland of gonadectomized hamster treated with T plus finasteride or the new steroids. The IC50 value of these steroids was determined by measuring the conversion of radio labeled T to DHT. The results of this study carried out with 5alpha-reductase enzyme from hamster and human prostate showed that four of the six steroidal derivatives (5, 7, 9, 10) exhibited much higher 5alpha-reductase inhibitory activity, as indicated by the IC50 values than the presently used Proscar 3 (finasteride). The comparison of the weight of the hamster's prostate gland indicated that compound 5 had a comparable weight decrease as finasteride. The overall data of this study showed very clearly those compounds 5, 7, 9, 10 are good inhibitors for the 5alpha-reductase enzyme.

Deuterated analogs of pregnenolone and pregnenolone sulfate with three atoms of deuterium in position 19 were prepared. The synthetic approach was developed on derivatives of dehydroepiandrosterone, where initial intermediates were well characterized, and then applied to the pregnenolone series. Starting 19-hydroxy compounds were transformed into 3alpha,5-cycloderivatives to simplify the Jones oxidation into the corresponding 19-oic acids. After oxidation, rearrangement to 3-hydroxy-5-enes, and suitable protection, two deuterium atoms were introduced by lithium aluminum deuteride reduction. Mesylate exchange by iodide in the presence of zinc and deuterium oxide added third deuterium atom. Deprotection gave title analogs with about 93-95% content of d3-derivative, the rest was mainly not fully deuterated d2-analogue as followed from the mass spectra analysis. Thus, 3beta-hydroxy[19-2H3]androst-5-en-17-one was prepared in 14 steps from 19-hydroxy-17-oxoandrost-5-en-3beta-yl acetate in 8.9% yield, the analogous sequence in the pregnenolone series gave 3beta-hydroxy[19-2H3]pregn-5-en-20-one in 7.3% yield. Corresponding sulfates were prepared via pyridinium salts in 53 and 57% yields, respectively. Fully assigned NMR data of selected pregnenolone derivatives were given.

In the search for potent inhibitors of P450 17, the key enzyme in androgen biosynthesis, a series of steroidal inhibitors were synthesized and tested toward rat and human P450 17. Small aliphatic heterocycles (aziridine, oxirane, thiirane, diaziridine, diazirine, azetidine) were introduced into the 17beta-position of anstrost-5-en-3beta-ol. After identifying that aziridine is the most suitable functional group to coordinate with the heme iron, modifications of the steroidal skeleton were performed for further optimization. A wide range of inhibitory potencies toward P450 17 were found for the 21 test compounds. The most potent inhibitors toward the human and rat enzyme were aziridine compounds 3 (IC(50) rat: 0.21 microM, K(i) = 3 nM; IC(50) human: 0.54 microM, K(i) = 8 nM), 5 (IC(50) rat: 0.43 microM, K(i) = 7 nM; IC(50) human: 0.29 microM, K(i) = 4 nM), and 8 (21R:21S = 1:1; IC(50) rat: 0.53 microM, K(i) = 9 nM; IC(50) human: 0.40 microM, K(i) = 6 nM) which were more potent than the reference ketoconazole (IC(50) rat: 67 microM; IC(50) human: 0.74 microM). The inhibitory potency depends markedly on the stereochemistry at C20 of the inhibitors. This effect is more pronounced for the rat enzyme. Tested for selectivity, the highly potent inhibitors show poor inhibitory activity toward P450 arom, P450 scc, P450 TxA(2), and 5alpha-reductase. Tested for in vivo activity, 3 and 8 (0.019 mmol/kg) decreased the plasma testosterone concentration in rats by 81% and 84% after 2 h.

17 alpha-Hydroxylase/C17-20-lyase (P450 17, CYP 17) and 5 alpha-reductase are the key enzymes in androgen biosynthesis and targets for the treatment of prostate cancer and benign prostatic hyperplasia. In the search of inhibitors for both enzymes, 23 pregnenolone- or progesterone-based steroids were synthesized bearing an oxime group connected directly or via a spacer to the steroidal D-ring. Tested for inhibition of human and rat P450 17, some pregnenolone (9, 11, 14) and a series of progesterone compounds (17-20) turned out to be highly active inhibitors of the human enzyme. The most active compound was Z-21-hydroxyiminopregna-5, 17(20)-dien-3 beta-ol (9) showing K(i) values of 44 and 3.4 nM for the human and rat enzymes, respectively, and a type II UV-difference spectrum indicating a coordinate bond between the oxime group and the heme iron. In contrast to the pregnenolones which showed no inhibition of 5 alpha-reductase isozymes 1 and 2, the progesterones 16, 17, 20, 21, and 23 showed marked inhibition, especially toward the type 2 enzyme. Compounds 17 and 20 were identified as potent dual inhibitors of both P450 17 and 5 alpha-reductase. Tested for selectivity, the most potent P450 17 inhibitors 9, 10, and 14 showed no or only marginal inhibition of P450 arom, P450 scc, and P450 TxA(2). Selected compounds were tested for inhibition of the target enzymes using whole-cell assays. Compounds 9-11 strongly inhibited P450 17 being coexpressed with NADPH-P450 reductase in E. coli cells, and 16, 20, and 23 markedly inhibited 5 alpha-reductase expressed in HEK 293 cells. Tested for in vivo activity, 9 (0.019 mmol/kg) decreased the plasma testosterone concentration in rats after 2 and 6 h by 57% and 44%.

For the purpose of applying the particular antibodies as a new diagnostic procedure for atherosclerosis and related diseases, we successfully achieved the synthesis of the fatty sterol with a linker, then linked the target protein to this sterol. Synthesis was started from pregnenolone and achieved by the Grignard reaction with pentenyl magnesium bromide, regioselective photoaddition of thiolacetic acid toward the 25-double bond, esterification of 3-OH with linoleic anhydride, in situ conjunction of the cross-linker (MBS) to the thiol group after selective deprotection from its acetyl ester, and finally by the reaction with protein such as KLH or albumin through this linker.

The unnatural enantiomers of dehydroepiandrosterone sulfate (1), pregnenolone sulfate (2), and (3alpha,5beta)-3-hydroxypregnan-20-one sulfate (3), compounds 4-6, respectively, were prepared by total steroid synthesis. The enantioselectivity of the compounds as negative modulators of the GABAA receptors present in cultured rat hippocampal neurons was examined using electrophysiological methods. Enantioselectivity was found for the inhibitory actions of the dehydroepiandrosterone enantiomers. The IC50s for compounds 1 and 4 were 11 +/- 1 and 80 +/- 14 microM, respectively. Little, if any, enantioselectivity was found for the other two pairs of steroid sulfate inhibitors. The IC50s for compounds 2 and 5 were 82 +/- 12 and 76 +/- 27 microM, respectively. The IC50s for compounds 3 and 6 were 39 +/- 7 and 46 +/- 2 microM, respectively. The results suggest that the sites of action for the androstane and pregnane series of steroid sulfate blockers of GABA-mediated current are different. The observed enantioselectivity for the actions of dehydroepiandrosterone sulfate indicates that its inhibitory actions are mediated via a chiral recognition site and provides new evidence in support of the earlier hypothesis that there is a binding site for this compound on GABAA receptors. Conversely, the failure to observe enantioselectivity for the actions of pregnenolone sulfate and steroid sulfate 3 indicates that a chiral recognition site for these steroids does not exist on GABAA receptors and suggests that the effects of these compounds on this receptor's function may arise indirectly as a consequence of steroid-induced membrane perturbation.

Dihydroxycholesterol and pregnenolone were clearly detected on HPLC when 22R-hydroxycholesterol was incubated with a reconstituted P450scc system containing equimolar amounts of P450scc and adrenodoxin. The dihydroxycholesterol, which has been accepted to be an intermediate in the conversion of 22R-hydroxycholesterol to pregnenolone, accumulated when adrenodoxin was at a subsaturating level with respect to P450scc. The formation of the intermediate increased with increasing pH in the range of 7.2 to 8.1, and the ratio of the intermediate to the product, pregnenolone, increased with increasing pH. When the binding of P450scc to adrenodoxin was weakened by elevation of the ionic strength, the formation of the intermediate relative to the product increased. The apparent Km for dihydroxycholesterol at a subsaturating level of adrenodoxin was about 7 microM, in contrast to 4 microM at a saturating level of adrenodoxin, implying that the affinity of dihydroxycholesterol is lower at a subsaturating level of adrenodoxin than at a saturating one. These results suggest that a subsaturating level of adrenodoxin weakened the binding of dihydroxycholesterol to P450scc and thus the intermediate, dihydroxycholesterol, was released. An intermediate other than dihydroxycholesterol, obtained when cholesterol was used as the substrate, was identified as 22R-hydroxycholesterol by HPLC and mass spectroscopic analysis. The intermediate obtained when 22R-hydroxycholesterol was used as the substrate was identified as 20R,22R-dihydroxycholesterol by HPLC, mass, and 1H-NMR spectroscopic analyses. These results provide direct evidence that cholesterol is metabolized to pregnenolone by way of 22R-hydroxycholesterol and 20R,22R-dihydroxycholesterol by P45 scc.

Radioiodinated benzoyl esters and amides of epimeric 20-hydroxy- and 20-aminopregn-5-en-3 beta-ols were synthesized in an effort to find an agent that would be rapidly and selectively taken up by adrenal cortical tissue. Achievement of such a goal would provide a basis for the development of adrenal imaging agents superior to those currently available for clinical use. The iodobenzoyl derivatives were obtained by treating the appropriate epimer with 2-iodobenzoic acid in the presence of dicyclohexylcarbodiimide and 4-(dimethylamino)pyridine. The resulting esters and amides were readily labeled with radioiodine by isotope exchange with sodium iodide-125 in pivalic acid. Tissue distribution studies in female rats revealed that only the esters displayed appreciable adrenal specificity, and the ester having the same configuration at C-20 as cholesterol was significantly better than the corresponding C-20 epimer.

3 beta, 11 alpha, 15 beta-Trihydroxy-5-pregnen-20-one, an intermediate required for the synthesis of the oogoniols, has been prepared from 15 alpha-hydroxy-11-oxoprogesterone in an overall yield of 16%. The three isomers (at C-11, C-15) of the pregnene were also prepared.

A series of radioiodinated benzoate and carbamate esters of cholesterol and pregnenolone wherein the acyl moiety served as the carrier for radioiodine was synthesized and evaluated as potential imaging agents for the adrenal cortex. 2,6-Dimethyl-3-iodobenzoyl and N-(4-iodophenyl) carbamoyl groups were chosen as the acyl functionality in an attempt to provide esters resistant to in vivo hydrolysis. Tissue disposition studies in rats revealed that their biodistribution was determined by the attached sterol carrier-the cholesterol esters demonstrated significant uptake at 24 h in the adrenal whereas the corresponding pregnenolone derivatives showed only slight affinity for steroid-secreting tissues at this time.

The geometry of the condensation products between ethyl cyanoacetate and 20-ketosteroids (5 alpha-pregnane-20-one, 3 beta-hydroxypregn-5-en-20-one and 3 beta-acetoxypregn-5-en-20-one) was established by NMR spectra. Reduction of these steroid C-20 alkylidene cyanoacetates was shown to afford one of the two possible 20-C epimers, which seen to correspond to the 20 beta-methyl configuration.

A series of radioiodinated pregnenolone esters was prepared in an effort to find an agent that would be rapidly and selectively taken up by adrenal cortical tissue. Achievement of such a goal would provide the basis for the development of an adrenal imaging agent having several advantages over those agents currently available for clinical use. The radioiodinated esters for this study were readily prepared by treating pregnenolone with the appropriate iodobenzoic acid in the presence of dicyclohexylcarbodiimide (DCC) and 4-dimethylamino-pyridine (DMAP). The resulting esters were readily labeled with radioiodine by isotope exchange with sodium iodide-125 in pivalic acid. Subsequent tissue distribution studies in rats revealed that those esters displaying the most stability towards hydrolysis achieved the highest concentration in adrenal cortical tissue. For example, the 2,3,5-triiodobenzoate (6) showed an adrenal uptake of 23% of administered dose per gram of tissue at 0.5 hours. The achievement of high levels of radioactivity in the adrenal with this agent at early time periods warrants further evaluation of this agent in other animals.

We have discovered novel delta selective opiate antagonists of a non-peptide nature. Our lead compound at the present time is the mixed azine between estrone and naloxone, the compound named EH-NAL. In this paper we describe the stereochemistry of EH-NAL and an EH-NAL analog, the mixed azine between pregnenolone and naltrexone, the compound named PH-NX. The stereochemical assignments are based on the high-resolution 13C-NMR studies and on the X-ray structural determinations.