Letters in Drug Design & Discovery

Identification of novel and selective anticancer agents remains an important and challenging goal in pharmacological research. The indole nucleus, frequently encountered as a molecular fragment in natural products and pharmaceutically active compounds, was employed as the initial building block for the synthesis of a series of pyrazino[1,2-a]indoles 1a-k, variably substituted at the 6, 7, 8 and 9-positions. Compound 1e, bearing the methoxy group at the 8-position of the pyrazino[1,2-a]indole nucleus was identified as a novel potent antiproliferative agent against the human chronic myelogenous leukemia K562 cell line, but it was much less active against several other cancer cell lines. Comparison of positional isomers indicated that moving the methoxy group from the 8- to the 7- or 6-position, to furnish compounds 1f and 1g, respectively, yielded inactive compounds. The analysis of structure-activity relationships observed in the series of investigated compounds may represent the basis for the design of more active molecules.

A series of N,N'-Bis(2-hydroxylbenzyl)-1,2-ethanediamine derivatives and its schiff bases were synthesized, characterized and screened for in vitro antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella enterica. Result indicated that the ethylenediamine derivatives, N,N'-Bis(2-hydroxy-5-bromobenzyl)-1,2-ethanediamine (21), and N,N'-Bis(2-hydroxy-5-chlorobenzyl)-1,2-ethanediamine (22) showed the most favorable antimicrobial activity exhibiting LC(50) of 11.6 and 8.79 muM against S.enterica, 86 and 138 muM against P. aeruginosa, and 140 and 287 muM against S. aureus, respectively. These compounds displayed highest level of resistance with S. aureus. Thus, the high level of activity seen with the compounds (21, 22) suggests that these compounds could serve as the leads for development of novel synthetic compounds with enhanced antimicrobial activity.

In order to investigate the SAR of Ezetimibe analogs for cholesterol absorption inhibitions, amide group and electron-deficient pyridine ring were introduced to the C-(3) carbon chain of Ezetimibe. Eight new derivatives of the 2-azetidinone cholesterol absorption inhibitors have been synthesized, and all of them were enantiomerically pure. All the new compounds were evaluated for their activity to inhibit cholesterol absorption in hamsters, and most of them showed comparable effects in lowering the levels of total cholesterol in the serum.

Human E1 is a key player in protein ubiquitination, however the E1 structure is not available. In this paper, we describe the derivation of a human E1 structure using molecular modelling based on the crystal structure of S. cerevisiae E1 and M. Musculus E1. Key interactions between our E1 model and ubiquitin are also discussed.

In this paper we review and discuss three of the most exciting and promising cytokines for therapeutic intervention and immunomodulation of immune responses including those on mucosal surfaces. The main properties of IL-12, IL-15 and IL-7 are described and the studies utilizing these cytokines as immunomodulators and vaccine adjuvants discussed.

3-N-alkyloxyestradiol derivatives were synthesized, characterized and tested for activity in MCF-7 human breast cancer cells. Among the compounds, the diisopropyl and piperidinyl derivatives were found to be more active than 4-hydroxytamoxifen (HO-Tam), the active metabolite of tamoxifen based upon IC(50) values. The IC(50)s were correlated with structures using molecular modeling.

Identification of novel and selective anticancer agents remains an important and challenging goal in pharmacological research. In search of new compounds with strong antiproliferative activity and simple molecular structure, we have synthesized three different series of compounds in which different substituents were linked to the 3-amino position of the 2-(3', 4', 5'-trimethoxybenzoyl)-benzo[b]furan or benzo[b]thiophene ring system. These substituents, corresponding to acetyl/haloacetyl, α-bromoacryloyl and nitrooxyacetyl moieties had different electrophilic properties. The benzoheterocycle parent structures were selected because of their reported bioactivities. Compounds bearing a methoxy group at the 6-position of the benzo[b]furan skeleton, were identified as potent antiproliferative agents against the human chronic myelogenous K562 and murine L1210 leukemia cell lines. Comparison of positional isomers indicated that moving the methoxy group from the 6- to the 5- or 7-position yielded inactive compounds. The effects of a selected series of compounds on cell cycle progression correlated well with their strong antiproliferative activity and inhibition of tubulin polymerization. The analysis of structure-activity relationships observed in the series of compounds described here may represent a platform for the design of more active molecules.

AIMS: One promising approach for treatment of Alzheimer's disease (AD) is use of anti-amyloid therapies, based on the hypothesis that increases in amyloid-beta (Aβ) deposits in brain are a major cause of AD. Several groups have focused on Aβ immunotherapy with some success. Small molecules derivatives of Congo red have been shown to inhibit Aβ aggregation and protect against Aβ neurotoxicity in vitro. The agents described here are all small molecule Aβ-binding agents (SMAβBA's) derivatives of Congo red. MAIN METHODS: Here, we have explored the anti-amyloid properties of these SMAβBA's in mice doubly transgenic for human prensenilin-1 (PS1) and APP gene mutations that cause early-onset AD. Mice were treated with either methoxy-X04, X:EE:B34 and X:034-3-OMe1. After treatment, brains were examined for Aβ-deposition, using histochemistry, and soluble and insoluble Aβ levels were determined using ELISA. KEY FINDINGS: A range of anti-amyloid activity was observed with these three compounds. PS1/APP mice treated with methoxy-X04 and X:EE:B34 showed decrease in total Aβ load, a decrease in Aβ fibril load, and a decrease in average plaque size. Treatment with methoxy-X04 also resulted in a decrease in insoluble Aβ levels. The structurally similar compound, X:034:3-OMe1, showed no significant effect on any of these measures. The effectiveness of the SMAβBA's may be related to a combination of binding affinity for Aβ and entry into brain, but other factors appear to apply as well. SIGNIFICANCE: These data suggest that SMAβBA's may significantly decrease amyloid burden in brain during the pathogenesis of AD and could be useful therapeutics alone, or in combination with immunotherapy.

There is still an urgent need to develop nonnucleoside reverse transcriptase (RT) inhibitors (NNRTI) with a high-genetic barrier to resistance that facilitate patient adherence and allow durable suppression of HIV-1 replication. In this study, we describe the synthesis of a novel series of N-aminoimidazole (NAIM) analogs. Each of the NAIM analogs display potent activity against wild-type recombinant purified HIV-1 RT as well as RTs containing the K103N or Y181C resistance mutations. The analogs, however, do not exhibit significant antiviral activity in cell culture and were, in general, cytotoxic. Nevertheless, these data suggest that the NAIM backbone may provide a suitable scaffold from which inhibitors active against NNRTI-resistant HIV-1 could be developed.

Drug discovery in the field of oncology has been advanced mainly through the targeting of receptor tyrosine kinases. Both antibodies and small molecule inhibitors have been found to have successful applications in blocking the proliferative functions of these cell surface receptors. Based on these early successes, additional kinases within the cytoplasm have been found to promote cancer and, as such, have been recognized as feasible targets for additional modes of therapies. Unlike these oncogene targets, most tumor suppressors are irreversibly altered during cancer progression and therefore are not feasible targets for therapy. However, a subset of these genes is reversibly epigenetically suppressed. One such gene is BRM, and when it is re-expressed in cancer cells, this gene halts their growth. Moreover, as the key catalytic subunit of the SWI/SNF complex, BRM is centrally important to a host of anticancer pathways and cellular mechanisms, and its status may serve as a biomarker. Restoring its expression will both reconnect a number of growth-controlling pathways and affect cellular adhesion, DNA repair, and immune functions. For these reasons, restoring BRM expression is not only feasible, but potentially a potent form of anticancer therapy. To identify BRM-restoring compounds, we developed a cell-based luciferase assay. In this review, we discuss some of the challenges we encountered, issues related to this type of drug discovery, and our future ambitions. We hope this review will provide insight to this type of endeavor and lead to more investigations pursuing this type of drug research.

The syntheses and cytotoxic activity of coumarin-estrogen conjugates are described. In vitro results indicated that conjugates 10, 11 and 13 show growth inhibitory activities at 5-dose concentration (100, 10, 1, 0.1, 0.01 muM) against the following NCI-7- human breast cancer cell lines: BT-549, HS 578T, MCF 7, MDA-MB-231/ATCC, MDA-MB-435, NCI/ADR-RES, and thus serve as new leads for further development of antibreast cancer agent.

Cholinesterases (ChEs) play a vital role in the regulation of cholinergic transmission. The inhibition of ChEs is considered to be involved in increasing acetylcholine level in the brain and thus has been implicated in the treatment of Alzheimer’s disease. We have designed and synthesized a series of novel indole derivatives and screened them for inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Most of the tested compounds exhibited inhibitory activity against AChE and BChE. Among them 4f and 6e showed the highest AChE inhibitory activity with IC50 91.21±0.06 and 68.52±0.04 μM, respectively. However compound 5a exhibited the highest inhibitory activity against BChE (IC50 55.21±0.12 μM).

Imidazopyridines and imidazopyrimidines have been prepared and tested for their antibacterial activity in vitro. Structure activity relationship studies indicate (SAR) that a modulation of both natures of arm in position 3 and atom in position 8 of these compounds has a direct impact on the antibacterial activity.

The ability of the docking program AutoDock in studying the binding of small molecules to DNA is examined. Herein, we report molecular dynamic studies with the relaxed complex method applied to DNA, and viscosimetric titration results, performed to investigate a possible DNA-binding mode of a model compound of the previously reported “two armed” class of binders.

A number of new derivatives of monoterpenoid with a para-menthane framework 3-methyl-6-(prop-1-en-2- yl)cyclohex-3-ene-1,2-diol (-)-3 were synthesized. The antiviral activity of (-)-3 and its derivatives against the pandemic influenza virus A/California/07/09 (H1N1)v was studied in vitro. Compound (-)-3 was found to be active against this virus (selectivity index 7.5); for mononicotinate (+)-6 the selectivity index was 17. The absolute configuration of compound 6 was shown to be critical for its antiviral activity.

Several 6H-indeno[1,2-c]isoquinolin-5,11-diones and 5H-dibenzo[c,h][1,6]naphthyridin-6-ones were synthesized and evaluated for their relative topoisomerase I-targeting activity and cytotoxicity. Comparative studies were performed in P388, RPMI8402, and U937 tumor cell lines, as well as their camptothecin-resistant variants, i.e. P388 / CPT45, CPT-K5, and U937 / CR, respectively. The relative cytotoxic activity of these compounds in cell lines known to overexpress efflux transporters that are associated with multidrug resistance or are known to be resistant to topoisomerase II-targeting agents was also determined. Our results suggest that some of these compounds are highly potent TOP1-specific poisons with cytotoxic activity rivaling that of camptothecin and different drug-resistant profiles.

Ten 1-benzenesulfonyl-1,2,3,4-tetrahydroquinoline (BSTHQ) were synthesized and characterized and their antiprotozoal activities were investigated. This small library was designed by combining two chemical moieties that are known to be biologically active by itself. The BS group seems to be favorable for the antiparasitic activity, since the derivatives presented lower IC50 value than the precursor heterocycle. Most compounds were moderately active against T cruzi, but 3 showed a promising IC50 value (9.76μM) with low cytotoxicity (L6). Also, 3, 6 and 9 showed interesting activity and reasonable selectivity against P. falciparum. These derivatives are considered as lead scaffolds and merit further exploration through structure optimization.

High anticonvulsive and anxiolytic activities of 8-trifluoromethyl-6-amino-benzopentathiepin 5, which can be synthesized by new simple and effective method, have been found. The transformation of the amino group in compound 5 to the amide group drastically changed the biological activity of the compounds.

A series of nitric oxide-donating derivatives of [1,2,4]triazol-5(4H)-one (9a-f and 15a-f) as a novel class of angiotensin II receptor AT1 antagonists have been designed and synthesized by coupling furoxan and nitric oxide with lead compound 1. The synthesized compounds were evaluated for their antagonism of AT1 receptor with induced contraction in the rabbit thoracic aortic ring and the results showed that compounds 9b, 15b and 15d exhibited potent antagonistic activity of AT1 receptor. Moreover 9b, 15b, 15d, 15e had good maximum NO release amount of this series.

The docking study on a series of 7H-thiazolo[3,2-b]-1,2,4-triazin-7-one derivatives with acetylcholinesterase has been demonstrated. The synthesis and characterization of a series of 7H-thiazolo[3,2-b]-1,2,4-triazin-7-one derivatives were described. All target compounds were evaluated in vitro for the inhibitory activities against AChE via Ellman colorimetric assay. Most of the target compounds possessed anti-acetylcholinesterase activity. The preliminary structure-activity relationships were discussed.

In exploring for templates to devise novel antagonists for the integrins α4β1 and α4β7, was a series of compounds identified possessing a 1,2,4-triazolo[2,3-a]pyrrole structural subunit. Compound 11, for example, was found to antagonize α4β1-VCAM-1 and α4β7-MAdCAM-1 adhesion with IC50 values of 80 and 20 nM, respectively.

1,3-dioxane carboxylic acid derivatives were prepared based on our previous studies directed towards identifying novel pharmacophore for the development of PPAR α/γ dual agonists. Based on the typical topology of PPAR agonists we focused our design approach on modifying lipophilic tail and prepared a series of compounds by replacing the oxazole moiety of our previously reported compound with optimized lipophilic groups. Compound 8a was found to be a weak PPAR activator but exhibited potent hypolipidemic and anti-hyperglycemic activities in vivo due to superior bioavailability, whereas 8f exhibited potent in vitro and invivo effects. The activity of 8f is further supported by molecular docking study.

A series of some newer 2, 5-disubstituted-1, 3, 4-oxadiazole derivatives (5a-5j) were synthesized and evaluated for anticancer activity. Compound 5f showed excellent activity in majority of the cell lines.

In this paper we report the synthesis and the inhibition on Human Leucocyte Elastase (HLE) of a new series of thieno[2,3-d][1,3]oxazin- or thioxazin-4-ones 3a-o and thieno[3,2-d][1,3]oxazin- or thioxazin-4-ones 6a-d. New derivatives have inhibitory activity in the micromolar range and among them, 2-(3- trifluoromethylphenylamino)-4H-thieno[2,3-d][1,3]oxazin-4-one 3h and 5,6-dimethyl-2-(4-nitrophenylamino)- 4H-thieno[2,3-d][1,3]thioxazin-4-one 3o were the most interesting.

Tandem cyclizations to [2,5'] bis-1,3-azoles provided simplified and stable models of biological active marine natural products. The cytotoxic activity in HCT-15 cells and the effect on the L4 larvae of Nippostrongylus brasiliensis of the heterocycles were evaluated and provided data that serve for the preparation of bioselective new therapeutic agents.

Fifteen new heterocyclic thiazolidinones have been synthesized from one-pot reactions of piperonylamine, arenealdehydes and mercaptoacetic acid. These compounds plus ten 2-aryl-3-(benzyl)-1,3-thiazolidin-4-ones which had been previously synthesized, were evaluated as antibacterial agents against Mycobacterium tuberculosis H37Rv using the Alamar Blue susceptibility test and their activity expressed as the minimum inhibitory concentration (MIC) in μg/mL. Six of the series exhibited modest activity when compared to the first line drugs such as isoniazid (INH) and rifampicin (RIP). Therefore this class of compounds could be a good starting point to develop new lead compounds in the treatment of multi-drug resistant tuberculosis.

A series of new 1,3-disubstituted-1H-pyrazol-5-ols (3) which are the analogues of known radical scavenger `edaravone' are synthesized, characterized and evaluated for DPPH scavenging capacity. The docking studies are carried out for these compounds in the enol form and also in the respective keto form against the proteins and peptides involved in Alzhemier disease signal cascade. Some of them showed good radical scavenging capacity and molecular binding.

Synthesis, biological evaluation and structure-activity relationships for a series of 8-sulfamoyl-1,3- dioxo-4-methyl-2,3-dihydro-1H-pyrrolo[3,4-c]quinolines are described. These compounds represent a new chemotype of nonpeptide small molecule inhibitors of caspase-3. Among the studied compounds, several potent inhibitors have been identified. The most active compounds within this series inhibited caspase-3 with IC50 in the range of 23-30 nM.

Using different heterocycle formation methodologies (Deoxo-Fluor, DAST, POCl3, TosMIC), [2,5']bis-1,3- azoles were prepared as stable analogs of bengazoles, a family of potent anthelmintic marine natural products. The cytotoxic activity of these heterocycles and their precursors on HCT-15 cells and the effect on the L4 larvae of Nippostrongylus brasiliensis were evaluated.

In this work we report the tuberculostatic profile of a series of 5-phenyl-1,3,4-thiadiazole-2-arylhydrazone derivatives (1a-m). The evaluation of their in vitro antibacterial activity against Mycobacterium tuberculosis H37Rv was expressed as the minimum inhibitory concentration (MIC) in μg/mL. The compounds 1g and 1h exhibited inhibitory activity of 6.25 μg/mL and 1.25 μg/mL respectively, and can be considered as a good start point for the discovery of new lead compounds in the field of multi-drug resistant tuberculosis.

In this work we reported the design, synthesis and evaluation of the anti-inflammatory, analgesic, and antiplatelet properties of new 1,3,4-thiadiazole derivatives, structurally planed by exploiting the molecular hybridization approach between diuretic drug acetazolamide and a 1,3-benzodioxole COX-2 inhibitor, previously developed. The in vivo pharmacological evaluation of these new compounds lead us to identify the para-fluoro-substituted derivative 8b as a new prototype, more active that celecoxib at the same molar concentration.

In searching for better anticonvulsant drug and the importance of semicarbazones and 2,5-disubstituted 1,3,4- oxadiazoles as anticonvulsant pharmacophore, a series of novel substituted semicarbazones were designed, synthesized and evaluated for their anticonvulsant activity. Among all the synthesized compounds, N1-(5-{2-[(2,6- dichlorophenyl)amino]benzyl}-1,3,4-oxadiazol-2-yl)-N4-[1-(4-hydroxyphenyl)(phenyl) methanone]-semicarbazone 12 emerged out as the most potent compound, showing considerable activity in maximal electroshock seizure (at 100 mg/kg after 0.5 h and at 300 mg/kg after 4.0 h) and subcutaneous pentylenetrtrazole model (at 300 mg/kg after 4.0 h) without any neurotoxicity (up to 300 mg/kg after 4.0 h). The results of the present study validated that the pharmacophore model with four binding sites is essential for anticonvulsant activity.

A new series of 5-[N-(3-(5-substituted)-1,3,4-thiadiazolyl)]amino-1-methyl-4-nitroimidazoles (6ah) has been designed, synthesized and examined for their ability against Trypanosoma cruzi. The compounds were prepared by nucleophilic aromatic substitution. Several bases were investigated as proton scavengers, and lithium diisopropylamide (LDA) was found to be the best base giving products in good yields.

Some alkylthio, alkylsulfinyl and alkylsulfonyl-5-(5-nitro-2-thienyl)-1,3,4-thiadiazoles were synthesized and evaluated against Helicobacter pylori. The antibacterial data indicated that most compounds exhibited significant inhibitory activity against H. pylori- more potent than standard drug metronidazole. Among them, 2-ethylsulfinyl-5-(5-nitro-2- thienyl)-1,3,4-thiadiazole was the most potent compound tested against clinical isolates of H. pylori. Generally the SAR of this series of compounds indicated that both the structure of the alkyl pendent and the S, SO or SO2 linker dramatically impact the antibacterial activity against H. pylori.

1,4-dihydropyridines are the emerging class of antitubercular agents. In this protocol we present, the syntheses, characterization details for the conformation of structures, antitubercular and anticancer activity results for some novel 1,4-dihydropyridines. The comparative molecular field analysis (CoMFA) model for 1,4-dihydropyridines was derived. The 3D QSAR model demonstrated good ability to predict activity of studied compounds (r2 = 0.97, q2 = 0.81). Based on the CoMFA steric and electrostatic contour maps, structure activity relationships were established for antitubercular activity.

The anticancer activities of six imido-substituted 2-chloro-1,4-naphthoquinone derivatives on one androgendependent, LNCaP, and two androgen-independent, PC3 and DU145, human prostate cancer cell lines are reported. The open chain imides (2-4) showed more potency in all three cell lines. In addition the microwave-assisted synthesis of five of these compounds is reported.

Vicinal 1-(4-methylsulfonyl)benzene-5-(3-pyridyl) substituted pyrazole compound containing a nitric oxide (NO)-donating group at the 3-position of the pyrazole ring was synthesized and evaluated for its ability to inhibit COX isozymes in human whole blood. We report here the synthesis of 4-{3-[(1Z)-4- (nitrooxy)but-1-enyl]-5-(3-pyridyl)pyrazolyl}-1-(4-methylsulfonyl)benzene (9) and its COX-2 inhibitory potency.

A series of enediyne prodrugs with (E)- or (Z)-3-hydroxy-4-(arylmethylidene)cyclodeca-1,5- diyne scaffolds have been synthesized via an intramolecular Nozaki-Hiyama-Kishi reaction as the key step. Cytotoxicity in micro molar range against P388 cancer cell line was observed for selected compounds and a structure-activity relationship is discussed.

The leishmanicidal and trypanocidal activities of chlorinated 1,7- and 1,8-naphthyridines were evaluated against cultured of L. amazonensis promastigote and T. cruzi epimastigote forms. Active compounds were also tested against blood trypomastigotes and their toxicity to Vero cells. Among the compounds evaluated 10 was the most active against L. amazonensis promastigotes and T. cruzi epimastigotes, IC50= 8.6 μM and IC50 =20.4 μM, respectively.

A series of new thiourea derivatives of 1,7,8,9-tetramethyl-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5-dione have been prepared. The compound 6 was tested for pharmacological activity on animal central nervous system (CNS). The data suggest that compound 6 significantly interacts with 5-HT2 receptors in the brain. The activities of synthesized compounds were evaluated for their cytotoxicity and anti-HIV-1 activity in MT-4 cells. Elementary analysis, MS, 1H NMR spectra confirmed the identity of the products. The molecular structure of 12 was determined by an X-ray analysis.

The thioxylation of the potent Neurokinin A antagonist MEN 10627 by Lawesson's reagent showed to be potentially useful for the post-synthetic manipulation of the related family of structurally peculiar bicyclic hexapeptides, whose synthesis in combinatorial manner has been recently described.

These diterpenes (1) and (2) were synthesized via epoxidation and rearrangements of (-)-Kaur-9(11), 16-dien-19-oate (7) isolated from Venezuelan species of espeletia (frailejon), and their antimicrobial and antitumoral activity were evaluated. Compound (1) showed GI50 values of 51.6 nM against CNS SF-539, LC50 = 100 M, log10 GI50 = -7.29; compound (2) showed GI50 at 4.17 M against breast cancer T47D, LC50 = 39 M and Log10 GI50 = -5.38. Our results suggest that these compounds are highly cytotoxic and cytostatic against human cancer cell lines.

New organotin (IV) based on 2-(thiophene-2-yl)acetic acid and 1-H-pyrazole-3-carboxylic acid derivatives 1-ae and 2a-e was prepared and characterized by IR, 1H and 13C NMR spectroscopy. These reactions were carried out under refluxing conditions using CHCl3 / EtOH (3:1) as solvents and 2:1 / 1:1 acid / metal oxide rations. The tin products were recuperated with moderate and good yields (55-85%). The Compounds (1b, 1e and 2e) were screened for their antitumor activities against two human tumor cell lines: HeLa, an epithelial cell from a fatal cervical carcinoma and HEK293, an embryonic kidney tumor. All three materials show an activity in vitro against these cell lines.

The synthesis of some steroidal dioximes (22-29) and their in vitro antineoplastic activity are described in this report. The oximino functionality was incorporated at position 3 and 17 of the 16- benzylidene substituted steroidal nucleus to study the importance of dioximino moiety on anticancer activity. The synthesized compounds were screened for their in vitro antitumor activity against the cell panel consisting of three lines (breast, brain and lungs) at NCI, Bethesda, USA. After selective analysis, compounds 23-28 indicated statistically significant antineoplastic activity for further studies.

We present the SAR study that led us to identification of the first inhibitors of type 7 17- hydroxysteroid dehydrogenase (17-HSD). The conversion of E1 into E2 is reduced by nearly 90 % by 17-(Nalkylformamido)- 4-methyl-4-aza-5-androstan-3-one compounds bearing a side chain containing 7 to 10 carbon atoms when tested at 0.3 M.

We report the synthesis and evaluation of a range of 2-, 3- and 4-substituted derivatives of benzyl imidazole as probes of the active site of the enzyme 17α-hydroxylase/17,20-lyase (P45017α). In conclusion, the positioning and nature of the substituent appears to play an important role in the inhibition of this enzyme complex.

We report the synthesis and evaluation of a range of triazole-based inhibitors of the two components of 17α-hydroxylase/17,20-lyase (P45017α). The results show that the compounds were poor inhibitors of 17α- OHase in comparison to lyase; they are therefore good lead compounds in the search for selective inhibitors of P45017α.

We report the preliminary results into the synthesis and evaluation of triazole-based compounds against the components of 17α-hydroxylase/17,20-lyase (P45017α), namely 17α-hydroxylase (17α-OHase) and 17,20-lyase (lyase). The results show that the compounds are weaker than ketoconazole but are good lead compounds in the search for inhibitors of P45017α, in particular, lyase.

17β-Hydroxysteroid dehydrogenase type 2 (17β-HSD2) catalyzes the oxidation of the potent estradiol (E2) to the less active estrogen estrone (E1). Inhibitors of this enzyme should maintain the local level of E2 in bone tissue when the E2 concentration in the circulation drops and therefore might be useful for the treatment of osteoporosis. In this work, novel non-steroidal spiro-δ-lactone compounds designed as 17β-HSD2 inhibitors were synthesized and their physicochemical and biological properties were investigated. These new spiro-δ-lactones are not sufficiently stable for further development and show low inhibition of the enzyme.

We report the synthesis, evaluation and rationalisation of the inhibitory activity of a series of compounds as probes of the active site of the type 3 of 17β-hydroxysteroid dehydrogenase (17β-HSD3). Results have provided invaluable insight into the active site (as well as supporting the previously reported model) of 17β-HSD3.