Showing papers in "Journal of Medicinal Chemistry in 2002"
TL;DR: Reduced molecular flexibility, as measured by the number of rotatable bonds, and low polar surface area or total hydrogen bond count are found to be important predictors of good oral bioavailability, independent of molecular weight.
Abstract: Oral bioavailability measurements in rats for over 1100 drug candidates studied at SmithKline Beecham Pharmaceuticals (now GlaxoSmithKline) have allowed us to analyze the relative importance of molecular properties considered to influence that drug property. Reduced molecular flexibility, as measured by the number of rotatable bonds, and low polar surface area or total hydrogen bond count (sum of donors and acceptors) are found to be important predictors of good oral bioavailability, independent of molecular weight. That on average both the number of rotatable bonds and polar surface area or hydrogen bond count tend to increase with molecular weight may in part explain the success of the molecular weight parameter in predicting oral bioavailability. The commonly applied molecular weight cutoff at 500 does not itself significantly separate compounds with poor oral bioavailability from those with acceptable values in this extensive data set. Our observations suggest that compounds which meet only the two cr...
5,191 citations
TL;DR: High-throughput and virtual screening is widely used to discover novel leads for drug design, and aggregate formation appears to explain the activity of many nonspecific inhibitors and may account for theActivity of many promiscuous screening hits.
Abstract: High-throughput and virtual screening are widely used to discover novel leads for drug design. On examination, many screening hits appear non-drug-like: they act noncompetitively, show little relationship between structure and activity, and have poor selectivity. Attempts to develop these peculiar molecules into viable leads are often futile, and much time can be wasted on the characterization of these “phony” hits. Despite their common occurrence, the mechanism of action of these promiscuous molecules remains unknown. To investigate this problem, 45 diverse screening hits were studied. Fifteen of these were previously reported as inhibitors of various receptors, including β-lactamase, malarial protease, dihydrofolate reductase, HIV Tar RNA, thymidylate synthase, kinesin, insulin receptor, tyrosine kinases, farnesyltransferase, gyrase, prions, triosephosphate isomerase, nitric oxide synthase, phosphoinositide 3-kinase, and integrase; 30 were from an in-house screening library of a major pharmaceutical co...
1,029 citations
TL;DR: Using Daylight fingerprints, this report shows that for IC(50) values determined as a follow-up to 115 high-throughput screening assays, there is only a 30% chance that a compound that is > or = 0.85 (Tanimoto) similar to an active is itself active.
Abstract: To design diverse combinatorial libraries or to select diverse compounds to augment a screening collection, computational chemists frequently reject compounds that are ≥0.85 similar to one already chosen for the combinatorial library or in the screening set. Using Daylight fingerprints, this report shows that for IC50 values determined as a follow-up to 115 high-throughput screening assays, there is only a 30% chance that a compound that is ⩾ 0.85 (Tanimoto) similar to an active is itself active. Although this enrichment is greater than that found with random screening and docking to three-dimensional structures, this low fraction of actives within similar compounds occurs not only because of deficiencies in the Daylight fingerprints and Tanimoto similarity calculations but also because similar compounds do not necessarily interact with the target macromolecule in similar ways. The current study emphasizes the statistical or probabilistic nature of library design and that perfect results cannot be expected.
794 citations
TL;DR: 6alpha-ethyl-chenodeoxycholic acid (6-ECDCA) was shown to be a very potent and selective FXR agonist and to be endowed with anticholeretic activity in an in vivo rat model of cholestasis.
Abstract: A series of 6α-alkyl-substituted analogues of chenodeoxycholic acid (CDCA) were synthesized and evaluated as potential farnesoid X receptor (FXR) ligands. Among them, 6α-ethyl-chenodeoxycholic acid (6-ECDCA) was shown to be a very potent and selective FXR agonist (EC50 = 99 nM) and to be endowed with anticholeretic activity in an in vivo rat model of cholestasis.
720 citations
TL;DR: A new structural class of nonpeptidic inhibitors employing a 1,2,5-trisubstituted benzimidazole as the central scaffold is designed and the double-prodrug 31, which showed strong oral activity in different animal species, was chosen for clinical development.
Abstract: The clinical syndromes of thromboembolism are evoked by an excessive stimulation of the coagulation cascade. In this context, the serine protease thrombin plays a key role. Considerable efforts have therefore been devoted to the discovery of safe, orally active inhibitors of this enzyme. On the basis of the X-ray crystal structure of the peptidelike thrombin inhibitor NAPAP complexed with bovine thrombin, we have designed a new structural class of nonpeptidic inhibitors employing a 1,2,5-trisubstituted benzimidazole as the central scaffold. Supported by a series of X-ray structure analyses, we optimized the activity of these compounds. Thrombin inhibition in the lower nanomolar range could be achieved although the binding energy mainly results from nonpolar, hydrophobic interactions. To improve in vivo potency, we increased the overall hydrophilicity of the molecules by introducing carboxylate groups. The very polar compound 24 (BIBR 953) exhibited the most favorable activity profile in vivo. This zwitter...
477 citations
TL;DR: The diversity of both hit lists and their dissimilarity from each other suggest that docking and HTS may be complementary techniques for lead discovery.
Abstract: High-throughput screening (HTS) of compound libraries is used to discover novel leads for drug development. When a structure is available for the target, computer-based screening using molecular docking may also be considered. The two techniques have rarely been used together on the same target. The opportunity to do so presented itself in a project to discover novel inhibitors for the enzyme protein tyrosine phosphatase-1B (PTP1B), a tyrosine phosphatase that has been implicated as a key target for type II diabetes. A corporate library of approximately 400 000 compounds was screened using high-throughput experimental techniques for compounds that inhibited PTP1B. Concurrently, molecular docking was used to screen approximately 235 000 commercially available compounds against the X-ray crystallographic structure of PTP1B, and 365 high-scoring molecules were tested as inhibitors of the enzyme. Of approximately 400 000 molecules tested in the high-throughput experimental assay, 85 (0.021%) inhibited the enz...
460 citations
TL;DR: The synthesis, biological evaluation, and SAR of the small heterocyclic thiadiazolidinones (TDZD) are described as the first non-ATP competitive inhibitor of GSK-3beta, based on the reactivity of sulfenyl chlorides.
Abstract: Glycogen synthase kinase 3 beta (GSK-3beta) has a central role in Alzheimer's disease (AD). Selective inhibitors which avoid tau hyperphosphorylation may represent an effective therapeutical approach to the AD pharmacotherapy and other neurodegenerative disorders. Here, we describe the synthesis, biological evaluation, and SAR of the small heterocyclic thiadiazolidinones (TDZD) as the first non-ATP competitive inhibitor of GSK-3beta. Their synthesis is based on the reactivity of sulfenyl chlorides. In GSK-3beta assays, TDZD derivatives showed IC(50) values in the micromolar range, whereas in other protein kinases assays they were devoid of any inhibitory activity. SAR studies allowed the identification of the key structural features. Finally, a possible enzymatic binding mode is proposed.
447 citations
TL;DR: A potent, selective, orally active LXR agonist was identified from focused libraries of tertiary amines and will be a valuable chemical tool to investigate the role of LXR in the regulation of reverse cholesterol transport and lipid metabolism.
Abstract: A potent, selective, orally active LXR agonist was identified from focused libraries of tertiary amines. GW3965 (12) recruits the steroid receptor coactivator 1 to human LXRα in a cell-free ligand-sensing assay with an EC50 of 125 nM and profiles as a full agonist on hLXRα and hLXRβ in cell-based reporter gene assays with EC50's of 190 and 30 nM, respectively. After oral dosing at 10 mg/kg to C57BL/6 mice, 12 increased expression of the reverse cholesterol transporter ABCA1 in the small intestine and peripheral macrophages and increased the plasma concentrations of HDL cholesterol by 30%. 12 will be a valuable chemical tool to investigate the role of LXR in the regulation of reverse cholesterol transport and lipid metabolism.
422 citations
TL;DR: 4,5-Disubstituted imidazole was found to be the best for the replacement of the cis double bond in CA-4 and Medicinal chemistry efforts led to the discovery of compounds 24h and 25f that were finding to be 32 and 82% bioavailable, respectively, in rat.
Abstract: The synthesis and structure-activity relationship study of a series of compounds with heterocycles in place of the cis double bond in combretastatin A-4 (CA-4) are described. Substituted tosylmethyl isocyanides were found to be the key intermediates in construction of the heterocycles. Cytotoxicities of the heterocycle-based CA-4 analogues were evaluated against NCI-H460 and HCT-15 cancer cell lines. 3-Amino-4-methoxyphenyl and N-methyl-indol-5-yl were the best replacements for the 3-hydroxy-4-methoxyphenyl in CA-4. 4,5-Disubstituted imidazole was found to be the best for the replacement of the cis double bond in CA-4. Medicinal chemistry efforts led to the discovery of compounds 24h and 25f that were found to be 32 and 82% bioavailable, respectively, in rat. Evaluation of 24h and 25f against murine M5076 reticulum sarcoma in mice revealed that both compounds were orally efficacious with an increase in life span of 38.5 and 40.5%, respectively.
405 citations
TL;DR: A series of pyrazine and quinoxaline derivatives have been synthesized and their activity against M. tuberculosis (Mtb) and Mycobacterium avium (MAC) are reported.
Abstract: A series of pyrazine and quinoxaline derivatives have been synthesized, and their activity against M. tuberculosis (Mtb) and Mycobacterium avium (MAC) are reported. The 4-acetoxybenzyl ester of pyrazinoic acid and 4‘-acetoxybenzyl 2-quinoxalinecarboxylate showed excellent activity against Mtb (MIC ranges of less than 1−6.25 μg/mL) but only modest activity against MAC (MICs of 4−32 μg/mL).
403 citations
TL;DR: A series of water-soluble L-lysyl- and L-alanyl-amide prodrugs of the lipophilic antitumor 2-(4-aminophenyl)benzothiazoles has been synthesized to address formulation and bioavailability issues related to the desired parenteral administration of the chosen clinical candidate.
Abstract: A series of water-soluble L-lysyl- and L-alanyl-amide prodrugs of the lipophilic antitumor 2-(4-aminophenyl)benzothiazoles has been synthesized to address formulation and bioavailability issues related to the desired parenteral administration of the chosen clinical candidate. The prodrugs exhibit the required pharmaceutical properties of good water solubility (in weak acid) and stability at ambient temperature and degradation to free base in vivo. The lysyl-amide of 2-(4-amino-3-methylphenyl)-5-fluorobenzothiazole (NSC 710305, 6d) has been selected for phase 1 clinical evaluation.
TL;DR: A key binding domain that is distinct from the adenosine 5'-triphoshate (ATP) binding site is exposed when the conserved activation loop adopts a conformation permitting lipophilic and hydrogen bonding interactions between this class of inhibitors and the protein.
Abstract: We report on a series of N-pyrazole, N'-aryl ureas and their mode of binding to p38 mitogen activated protein kinase. Importantly, a key binding domain that is distinct from the adenosine 5'-triphoshate (ATP) binding site is exposed when the conserved activation loop, consisting in part of Asp168-Phe169-Gly170, adopts a conformation permitting lipophilic and hydrogen bonding interactions between this class of inhibitors and the protein. We describe the correlation of the structure-activity relationships and crystallographic structures of these inhibitors with p38. In addition, we incorporated another binding pharmacophore that forms a hydrogen bond at the ATP binding site. This modification affords significant improvements in binding, cellular, and in vivo potencies resulting in the selection of 45 (BIRB 796) as a clinical candidate for the treatment of inflammatory diseases.
TL;DR: This study led to the identification of a new series of highly efficient molecular transporters that performed almost without exception better than heptaarginine itself, suggesting that spacing between residues is also important for transport.
Abstract: Short oligomers of arginine, either alone or when conjugated to therapeutic agents or large biopolymers, have been shown to cross readily a variety of biological barriers (e.g., lipid bilayers and epithelial tissue). Molecular modeling suggests that only a subset of the side chain guanidinium groups of these transporters might be required for transport involving contact with a common surface such as a plasma membrane or cell surface receptor. To evaluate this hypothesis, a series of decamers were prepared that incorporated seven arginines and three nonarginine residues. Several of these mixed decamers were comparable to the all arginine decamer in their ability to enter cells. More significantly, these decamers containing seven arginines performed almost without exception better than heptaarginine itself, suggesting that spacing between residues is also important for transport. The influence of spacing was more fully evaluated with a library of oligomers incorporating seven arginines separated by one or m...
TL;DR: A pharmacophore for QT-prolonging drugs, along with a 3D QSAR (CoMFA) study for a series of very structurally variegate HERG K(+) channel blockers, and a theoretical screening tool able to predict whether a new molecule can interact with the HERG channel and eventually induce the long QT syndrome.
Abstract: In this paper, we present a pharmacophore for QT-prolonging drugs, along with a 3D QSAR (CoMFA) study for a series of very structurally variegate HERG K(+) channel blockers. The blockade of HERG K(+) channels is one of the most important molecular mechanisms through which QT-prolonging drugs increase cardiac action potential duration. Since QT prolongation is one of the most undesirable side effects of drugs, we first tried to identify the minimum set of molecular features responsible for this action and then we attempted to develop a quantitative model correlating the 3D stereoelectronic characteristics of the molecules with their HERG blocking potency. Having considered an initial set of 31 QT-prolonging drugs for which the HERG K(+) channel blocking activity was measured on mammalian transfected cells, we started the construction of a theoretical screening tool able to predict whether a new molecule can interact with the HERG channel and eventually induce the long QT syndrome. This in silico tool might be useful in the design of new drug candidates devoid of the physicochemical features likely to cause the above-mentioned side effect.
TL;DR: A novel series of potent thio semicarbazone small-molecule inhibitors of the Trypanosoma cruzi cysteine protease cruzain have been identified and it is suggested that this is a promising direction for the development of new antitrypanosome chemotherapy.
Abstract: American trypanosomiasis, or Chagas' disease, is the leading cause of heart disease in Latin America. Currently there is an urgent need to develop antitrypanosomal therapy due to the toxicity of existing agents and emerging drug resistance. A novel series of potent thio semicarbazone small-molecule inhibitors of the Trypanosoma cruzi cysteine protease cruzain have been identified. Some of these inhibitors have been shown to be trypanocidal. We initially discovered that 3'-bromopropiophenone thio semicarbazone (1i) inhibited cruzain and could cure mammalian cell cultures infected with T. cruzi. 3'-Bromopropiophenone thio semicarbazone showed no toxicity for mammalian cells at concentrations that were trypanocidal. Following this lead, more than 100 compounds were designed and synthesized. A specific structure-activity relationship (SAR) was established, and many potent analogues with IC(50) values in the low nanomolar range were identified. Eight additional analogues were trypanocidal in a cell culture assay, and this indicates that aryl thio semicarbazone is a productive scaffold for killing the parasites. Kinetic studies show that these are time-dependent inhibitors. Molecular modeling studies of the enzyme-inhibitor complex have led to a proposed mechanism of interaction as well as insight into the SAR of the thio semicarbazone series. The nonpeptide nature of this series, small size, and extremely low cost of production suggest this is a promising direction for the development of new antitrypanosome chemotherapy.
TL;DR: A novel subseries of 4-anilinoquinazolines that possess basic side chains at the C-7 position of the quinazoline nucleus have been synthesized, and one of the compounds demonstrated highly significant, dose-dependent, antitumor activity in athymic mice.
Abstract: We have previously shown that 4-anilinoquinazolines can be potent inhibitors of vascular endothelial growth factor (VEGF) receptor (Flt-1 and KDR) tyrosine kinase activity. A novel subseries of 4-anilinoquinazolines that possess basic side chains at the C-7 position of the quinazoline nucleus have been synthesized. This subseries contains potent, nanomolar inhibitors of KDR (median IC(50) 0.02 microM, range 0.001-0.04 microM), which are comparatively less potent vs Flt-1 tyrosine kinase (median IC(50) 0.55 microM, range 0.02-1.6 microM). The compounds also retain some inhibitory activity against the tyrosine kinase associated to the endothelial growth factor receptor (EGFR) (median IC(50) 0.2 microM, range 0.075-0.8 microM) but demonstrate selectivity vs that associated to the FGF receptor 1 (median IC(50) 2.5 microM, range 0.9-19 microM). This selectivity profile is also evident in a growth factor-stimulated human endothelial cell (HUVEC) proliferation assay (i.e., inhibition of VEGF > EGF > FGF), with inhibition of VEGF-induced proliferation being achieved at nanomolar concentrations (median IC(50) 0.06 microM). Further examination of compound 2 (ZD6474) in recombinant enzyme assays revealed excellent selectivity for the inhibition of KDR tyrosine kinase (IC(50) 0.04 microM) vs the kinase activity of erbB2, MEK, CDK-2, Tie-2, IGFR-1R, PDK, PDGFRbeta, and AKT (IC(50) range: 1.1 to >100 microM). Anilinoquinazolines possessing basic C-7 side chains exhibited markedly improved aqueous solubility over previously described anilinoquinazolines possessing neutral C-7 side chains (up to 500-fold improvement at pH 7.4). In addition, aqueous solubility of the neutral fraction present at pH 7.4 of the basic subseries of anilinoquinazoline proved to be higher than that of the neutral analogue 1 (ZD4190). Oral administration of representative compounds to mice (50 mg/kg) produced plasma levels between 0.2 and 3 microM at 24 h after dosing. Our development candidate 2 demonstrated a very attractive in vitro profile combined with excellent solubility (330 microM at pH 7.4) and good oral bioavailability in rat and dog (> 80 and > 50%, respectively). This compound demonstrated highly significant, dose-dependent, antitumor activity in athymic mice. Once daily oral administration of 100 mg/kg of compound 2 for 21 days inhibited the growth of established Calu-6 lung carcinoma xenografts by 79% (P < 0.001, Mann Whitney rank sum test), and substantial inhibition (36%, P < 0.02) was evident with 12.5 mg/kg/day.
TL;DR: Optimization of the triarylimidazole hit 8 gave the selective inhibitor 14, which inhibits TGF-beta1-induced fibronectin mRNA formation while displaying no measurable cytotoxicity in the 48 h XTT assay.
Abstract: Screening of our internal compound collection for inhibitors of the transforming growth factor β1 (TGF-β1) type I receptor (ALK5) identified several hits. Optimization of the dihydropyrroloimidazole hit 2 by introduction of a 2-pyridine and 3,4-methylenedioxyphenyl group gave 7, a selective ALK5 inhibitor. With this information, optimization of the triarylimidazole hit 8 gave the selective inhibitor 14, which inhibits TGF-β1-induced fibronectin mRNA formation while displaying no measurable cytotoxicity in the 48 h XTT assay.
TL;DR: The results of the clinical trials indicate that low doses of Zoledronic acid are both efficacious and safe for the treatment of tumor-induced hypercalcemia, Paget's disease of bone, osteolytic metastases, and postmenopausal osteoporosis.
Abstract: Bisphosphonates (BPs) are pyrophosphate analogues in which the oxygen in P−O−P has been replaced by a carbon, resulting in a metabolically stable P−C−P structure. Pamidronate (1b, Novartis), a second-generation BP, was the starting point for extensive SAR studies. Small changes of the structure of pamidronate lead to marked improvements of the inhibition of osteoclastic resorption potency. Alendronate (1c, MSD), with an extra methylene group in the N-alkyl chain, and olpadronate (1h, Gador), the N,N-dimethyl analogue, are about 10 times more potent than pamidronate. Extending one of the N-methyl groups of olpadronate to a pentyl substituent leads to ibandronate (1k, Roche, Boehringer-Mannheim), which is the most potent close analogue of pamidronate. Even slightly better antiresorptive potency is achieved with derivatives having a phenyl group linked via a short aliphatic tether of three to four atoms to nitrogen, the second substituent being preferentially a methyl group (e.g., 4g, 4j, 5d, or 5r). The mos...
TL;DR: Kratz et al. as discussed by the authors proposed a macromolecular prodrug strategy for improved cancer chemotherapy based on two features: rapid and selective binding of thiol-reactive prodrugs to the cysteine-34 position of endogenous albumin after intravenous administration and release of the albumin-bound drug in the acidic environment at the tumor site due to the incorporation of an acidsensitive bond between the drug and the carrier.
Abstract: We have recently proposed a macromolecular prodrug strategy for improved cancer chemotherapy based on two features (Kratz, F.; et al. J. Med. Chem 2000, 43, 1253−1256.): (a) rapid and selective binding of thiol-reactive prodrugs to the cysteine-34 position of endogenous albumin after intravenous administration and (b) release of the albumin-bound drug in the acidic environment at the tumor site due to the incorporation of an acid-sensitive bond between the drug and the carrier. To investigate this therapeutic strategy in greater depth, four (maleinimidoalkanoyl)hydrazone derivatives of doxorubicin were synthesized differing in the length of the aliphatic spacer (1, −(CH2)2−; 2, −(CH2)3−; 3, −(CH2)5−; 4, −(CH2)7−). The albumin-binding doxorubicin prodrugs, especially the (6-maleimidocaproyl)hydrazone derivative of doxorubicin (3), are rapidly and selectively bound to the cysteine-34 position of endogenous albumin. 3 was distinctly superior to the parent compound doxorubicin in three animal tumor models (R...
TL;DR: In this article, a RP-HPLC method for the determination of EIogD oct values for chemical compounds from retention time of each sample of the compound using (EQ1) drop in equation is presented.
Abstract: A RP-HPLC method for the determination of EIogD oct values for chemical compounds from retention time of each sample of the compound using (EQ1) drop in equation. This method has been shown to be effective on a set of 90 molecules.
TL;DR: Novel antidiabetic arylsulfonamidothiazoles are presented that exert action through selective inhibition of the 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) enzyme, thereby attenuating hepatic gluconeogenesis.
Abstract: Novel antidiabetic arylsulfonamidothiazoles are presented that exert action through selective inhibition of the 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) enzyme, thereby attenuating hepatic gluconeogenesis. The diethylamide derivative 2a was shown to potently inhibit human 11beta-HSD1 (IC(50) = 52 nM), whereas the N-methylpiperazinamide analogue 2b only inhibited murine 11beta-HSD1 (IC(50) = 96 nM). Both compounds showed >200-fold selectivity over human and murine 11beta-HSD2. 2b was subsequently shown to reduce glucose levels in diabetic KKA(y) mice, substantiating the 11beta-HSD1 enzyme as a target for the treatment of type 2 diabetes.
TL;DR: Structural modification of the prototype EUK-8 yields compounds with enhanced catalase activity and, in turn, biological effectiveness, which supports the concept that salen-manganese complexes represent a class of SOD andCatalase mimetics potentially useful against ROS-associated diseases.
Abstract: Synthetic catalytic scavengers of reactive oxygen species (ROS) may have broad clinical applicability. In previous papers, two salen−manganese complexes, EUK-8 and EUK-134, had superoxide dismutase (SOD) and catalase activities and prevented ROS-associated tissue injury. This study describes two series of salen−manganese complexes, comparing catalytic ROS scavenging properties and cytoprotective activities. The compounds vary widely in ability to scavenge hydrogen peroxide, with this activity most influenced by salen ring alkoxy subsitution and aromatic bridge modifications. In contrast, all compounds show comparable SOD activities. The most active alkoxy-substituted catalase mimetics protected cultured cells from hydrogen peroxide, and a subset of these were also neuroprotective in a rodent stroke model. Thus, structural modification of the prototype EUK-8 yields compounds with enhanced catalase activity and, in turn, biological effectiveness. This supports the concept that salen−manganese complexes repr...
TL;DR: Quantitative structure-activity relationship (QSAR) analysis showed that, besides the essential pharmacophore (-NHCONHOH), hydrophobicity, molecular size/polarizability, and the presence of an oxygen-containing group at the ortho position (I) were important determinants for the antitumor activities.
Abstract: Thirty Schiff bases of hydroxysemicarbazide (Ar−CHNNHCONHOH) have been synthesized and tested against L1210 murine leukemia cells. The IC50 values were found to be in a range from 2.7 × 10-6 to 9.4 × 10-4 M. A total of 17 out of the 30 compounds had higher inhibitory activities than hydroxyurea (an anticancer drug currently used for the treatment of melanoma, leukemia, and ovarian cancer) against L1210 cells. Six compounds with IC50 values in micromolar range were 11- to 30-fold more potent than hydroxyurea (IC50 = 8.2 × 10-5 M). The partition coefficient (log P) and ionization constants (pKa) of a model compound [1-(3-trifluoromethylbenzylidene)-4-hydroxysemicarbazide, 1] were measured by the shake-flask method, and the measured log P was used to derive Hansch−Fujita π constant of −CHNNHCONHOH. On the basis of the newly derived π and those of other moieties, the partition coefficients (SlogP) of the other 29 compounds were calculated by the summation of π values. Quantitative structure−activity relations...
TL;DR: A computer-based method was developed for rapid and automatic identification of potential "frequent hitters" that will be a valuable tool for the prioritization of compounds from large databases, for compound purchase and biological testing, and for building new virtual libraries.
Abstract: A computer-based method was developed for rapid and automatic identification of potential "frequent hitters". These compounds show up as hits in many different biological assays covering a wide range of targets. A scoring scheme was elaborated from substructure analysis, multivariate linear and nonlinear statistical methods applied to several sets of one and two-dimensional molecular descriptors. The final model is based on a three-layered neural network, yielding a predictive Matthews correlation coefficient of 0.81. This system was able to correctly classify 90% of the test set molecules in a 10-times cross-validation study. The method was applied to database filtering, yielding between 8% (compilation of trade drugs) and 35% (Available Chemicals Directory) potential frequent hitters. This filter will be a valuable tool for the prioritization of compounds from large databases, for compound purchase and biological testing, and for building new virtual libraries.
TL;DR: The observed SAR offers insight into the requirements of the active sites on these enzymes, and is likely that these compounds will be metabolized to the corresponding phenols, with inhibitory activities against AChE and/or MAO-A or -B, different from those of the parent carbamates.
Abstract: Carbamate derivatives of N-propargylaminoindans (Series I) and N-propargylphenethylamines (Series II) were synthesized via multistep procedures from the corresponding hydroxy precursors. The respective rasagiline- and selegiline-related series were designed to combine inhibitory activities of both acetylcholine esterase (AChE) and monoamine oxidase (MAO) by virtue of their carbamoyl and propargylamine pharmacophores. Each compound was tested for these activities in vitro in order to find molecules with similar potencies against each enzyme. Compounds with such dual AChE and MAO inhibitory activities are expected to have potential for the treatment of Alzheimer's disease. The observed SAR also offers insight into the requirements of the active sites on these enzymes. A carbamate moiety was found to be essential for AChE inhibition, which was absent in the corresponding hydroxy precursors. The propargyl group caused 2-70-fold decrease in AChE inhibitory activity (depending on the position of the carbamoyl group) of Series I, but had little or no effect in Series II. Thus, the 6- and 7-carbamyloxyphenyls in Series I were either equipotent to, or slightly (2- to 5-fold) less active as AChE inhibitors than, the corresponding compounds in Series II, while the 4-carbamyloxyphenyls were more potent. The presence of the carbamate moiety in 6- and 7-carbamyloxyphenyls of Series I, considerably decreased MAO-A and -B inhibitory activity, compared to that of the parent hydroxy analogues, while the opposite was true for Series II. Thus, the 6- and 7-carbamyloxyphenyls in Series I were 2-3 orders of magnitude weaker MAO inhibitors while the 4- carbamyloxyphenyls were equipotent with the corresponding compounds in Series II. In both series, N-methylation of the propargylamine enhanced the MAO (A and B equally) inhibitory activities and decreased the AChE inhibitory activity. Two candidates belonging to the indan and tetralin ring systems (24c, 27b) and one phenethylamine (53d) were identified as possible leads for further development based on the following criteria: (a) comparable AChE and MAO-B inhibitory activities, (b) good to moderate AChE inhibitory activity, and (c) lack of strong MAO-A selectivity. However, it is likely that these compounds will be metabolized to the corresponding phenols, with inhibitory activities against AChE and/or MAO-A or -B, different from those of the parent carbamates. Thus, the apparent enzyme inhibition will be a result of the combined inhibition of all of these individual metabolites. The results of our ongoing in vivo screening programs will be published elsewhere.
TL;DR: Ultrafiltration experiments showed that binding of these gold(III) complexes to DNA is weak and reversible, and the mechanistic implications of these findings are discussed.
Abstract: Gold(III) compounds generally exhibit significant cytotoxic effects on cancer cell lines and are of potential interest as antitumor drugs. We report here on the solution chemistry, the cytotoxicity, and the DNA binding properties of two new bipyridyl gold(III) compounds: [Au(bipy)(OH)2][PF6] (1) and the organometallic compound [Au(bipyc-H)(OH)][PF6] (2) (bipyc = 6-(1,1-dimethylbenzyl)-2,2‘-bipyridine). Both compounds are sufficiently soluble, and stable for hours, within a physiological buffer at 37 °C; [Au(bipy)(OH)2][PF6], at variance with [Au(bipyc-H)(OH)][PF6], is quickly and quantitatively reduced by ascorbate. Both compounds showed relevant cytotoxic effects toward the A2780S, A2780R, and SKOV3 tumor cell lines; lower effects were detected on the CCRF-CEM/S and CCRF-CEM/R lines. In most cases the mechanisms of resistance to CDDP are only marginally effective against these gold(III) complexes. The interactions of [Au(bipy)(OH)2][PF6] and [Au(bipyc-H)(OH)][PF6] with calf thymus DNA were investigated ...
TL;DR: 9-benzyl-2-chloro-6-(2-furyl)purine exhibited relatively low cytotoxicity, and it was active against several singly drug-resistant strains of M. tuberculosis.
Abstract: 6-Arylpurines carrying a variety of substituents in the 9-position were prepared by Stille coupling between appropriately substituted 6-chloropurines and aryl(tributyl)tin, and the compounds were screened for antibacterial activity against Mycobacterium tuberculosis H37Rv. The lowest minimum inhibitory concentration value, 0.78 μg/mL, was found for 9-benzyl-2-chloro-6-(2-furyl)purine. This compound exhibited relatively low cytotoxicity, and it was active against several singly drug-resistant strains of M. tuberculosis.
TL;DR: Curcumin analogues, compounds 4, 20, 22, 23, and 39 have been identified as a new class of antiandrogen agents, and they could be developed into clinical trial candidates to control androgen receptor-mediated prostate cancer growth.
Abstract: A number of curcumin analogues were prepared and evaluated as potential androgen receptor antagonists against two human prostate cancer cell lines, PC-3 and DU-145, in the presence of androgen receptor (AR) and androgen receptor coactivator, ARA70. Compounds 4 [5-hydroxy-1,7-bis(3,4-dimethoxyphenyl)-1,4,6-heptatrien-3-one], 20 [5-hydroxy-1,7-bis[3-methoxy-4-(methoxycarbonylmethoxy)phenyl]-1,4,6-heptatrien-3-one], 22 [7-(4-hydroxy-3-methoxyphenyl)-4-[3-(4-hydroxy-3-methoxyphenyl)acryloyl]-5-oxohepta-4,6-dienoic acid ethyl ester], 23 [7-(4-hydroxy-3-methoxyphenyl)-4-[3-(4-hydroxy-3-methoxyphenyl)acryloyl]5-oxohepta-4,6-dienoic acid], and 39 [bis(3,4-dimethoxyphenyl)-1,3-propanedione] showed potent antiandrogenic activities and were superior to hydroxyflutamide, which is the currently available antiandrogen for the treatment of prostate cancer. Structure-activity relationship (SAR) studies indicated that the bis(3,4-dimethoxyphenyl) moieties, the conjugated beta-diketone moiety, and the intramolecular symmetry of the molecules seem to be important factors related to antiandrogenic activity. The data further suggest that the coplanarity of the beta-diketone moiety and the presence of a strong hydrogen bond donor group were also crucial for the antiandrogenic activity, which is consistent with previous SAR results for hydroxyflutamide analogues. When the pharmacophoric elements of dihydrotestosterone (DHT) and compound 4 are superposed, the resulting construct implies that the curcumin analogues may function as a 17alpha-substituted DHT. Compounds 4, 20, 22, 23, and 39 have been identified as a new class of antiandrogen agents, and these compounds or their new synthetic analogues could be developed into clinical trial candidates to control androgen receptor-mediated prostate cancer growth.