Synthesis and antipicornavirus activity of (R)- and (S)-1-[5-(4'-chlorobiphenyl-4-yloxy)-3-methylpentyl]-3-pyridin-4-yl-imidazolidin-2-one

The new pyridyl imidazolidinone derivative, 1-[5-(4'-chlorobiphenyl-4-yloxy)-3-methylpentyl]-3-pyridin-4-yl-imidazolidin-2-one (+/-)-1a, was synthesized and found to have an excellent antiviral activity against EV71 (IC50 = 0.009 microM). Therefore, both the enantiomers, (S)-(+)-1a and (R)-(-)-1a, have been prepared starting from readily available monomethyl (R)-3-methylglutarate (7) as a useful chiral building block and their antiviral activity was evaluated in a plaque reduction assay. Interestingly, we observed that the enantiomer (S)-(+)-1a was 10-fold more active against enterovirus71 (EV71) (IC50 = 0.003 microM) than the corresponding enantiomer (R)-(-)-1a (IC50 = 0.033 microM). Similar results were found against all five strains (1743, 2086, 2231, 4643, and BrCr) of EV71 tested. This demonstrated that the absolute configuration of the chiral carbon atom at the 3-position of the alkyl linker considerably influenced the anti-EV71 activity of these pyridyl imidazolidinones.     

Cytotoxic and antivascular 1-methyl-4-(3-fluoro-4-methoxyphenyl)-5-(halophenyl)-imidazoles

A series of 1-methyl-4,5-diphenylimidazoles 6 with various patterns of m-halogen substitution at the 5-phenyl ring were tested for cytotoxicity in cancer and nonmalignant cell lines and for their capacity to prevent tube formation in HUVEC cultures. Unlike the monofluoro and difluoro derivatives 6a and 6e, the monobromo and diiodo analogs 6c and 6h were strongly cytotoxic and inhibited the polymerization of tubulin and the tube formation by HUVEC. The dibromo derivative 6g displayed a unique selectivity for KB-3-1 cervix and PC-3 prostate cancer cells. It also inhibited the tube formation by HUVEC and the polymerization of tubulin which is indicative of its potential antiangiogenic activity in solid tumors.     

Diastereoselective reduction of 1-(4-fluorophenyl)-3(R)-[3-oxo-3-(4-fluorophenyl)-propyl]-4(S)-(4-hydroxyphenyl)azetidin-2-one to Ezetimibe by the whole cell catalyst Rhodococcus fascians MO22

The asymmetric microbial reduction of 1-(4-fluorophenyl)-3(R)-[3-oxo-3-(4-fluorophenyl)-propyl]-4(S)-(4-hydroxyphenyl)azetidin-2-one to 1-(4-fluorophenyl)-3(R)-[3(S)-hydroxy-3-(4-fluorophenyl)-propyl]-4(S)-(4-hydroxyphenyl)azetidin-2-one (Ezetimibe) by Rhodococcus fascians MO22 is described. The catalytic capability of the microorganism for reduction has been examined also with protected ketone, an intermediate from chemical synthesis of Ezetimibe. Various parameters of the bioreduction have been optimized: the strain converted 94.8% of ketone and 63% of protected ketone into Ezetimibe with the same de of 99.9%. In the later case, two chemical steps are replaced with a single biotransformation.     

1-(4-Methane(amino)sulfonylphenyl)-3-(4-substituted-phenyl)-5-(4-trifluoromethylphenyl)-1H-2-pyrazolines/pyrazoles as potential anti-inflammatory agents

2-Pyrazolins 14a–l and pyrazoles 15a–l were designed as celecoxib analogs for the evaluation of their in vitro COX-1/COX-2 inhibitory activity and the in vivo anti-inflammatory activity. Compounds 14i, 15a, 15d and 15f were the most COX-2 selective derivatives (S.I. = 5.93, 6.08, 5.03 and 5.27 respectively) while the pyrazoline derivatives 14g and 14i exhibited the highest AI activity (ED₅₀ = 190.5 and 160.1 μmol/kg po, respectively).     

Anti-inflammatory and anti-arthritic effects of new synthetic 3-(4-hydroxyphenyl)-4-(4-thiomethoxyphenyl)-1H-pyrrole-2,5-dione

We previously reported that 3-(4-hydroxyphenyl)-4-(4-thiomethoxyphenyl)-1H-pyrrole-2,5-dione (1, HMP) has a strong inhibitory effect on prostaglandin E(2) (PGE(2)) production. In this study, the anti-inflammatory and anti-arthritic effects of HMP were evaluated on LPS-induced RAW 264.7 macrophages and rats with carrageenan-induced paw edema and adjuvant-induced arthritis (AIA). The attenuation of PGE(2) production by HMP was found to be caused by the inhibition of cyclooxygenase-2 (COX-2) activity, but not COX-1 activity. However, HMP did not affect COX-2 at the protein or mRNA levels, whereas it suppressed the releases and expressions of inflammatory cytokines, such as, interleukin-1β (IL-1β) and IL-6 in LPS-induced macrophages. Furthermore, HMP suppressed LPS-induced nitric oxide (NO) production by down regulating the protein and mRNA expressions of inducible nitric oxide synthase (iNOS). In rats with carrageenan-injected acute inflammation, oral administration of HMP (25 or 50mg/kg, po) reduced paw swelling, and PGE(2) release and myeloperoxidase (MPO) activity in tissue. Furthermore, HMP (25 or 50mg/kg, po) significantly reduced paw swelling, arthritic indices and plasma PGE(2) concentrations in rat with AIA. These results show that HMP reduces swelling in a model acute inflammation and inhibits arthritic responses in a model of chronic inflammation via the inhibition of PGE(2) production. These results suggest that HMP is a potential therapeutic agent for the treatment of arthritis and associated disorders.     

Anticancer potential of 3-(arylideneamino)-2-phenylquinazoline-4(3H)-one derivatives

Different quinazoline derivatives have showed wide spectrum of pharmacological activities. Some 3-(arylideneamino)-phenylquinazoline-4(3H)-ones have been reported to possess antimicrobial activity. The present study has been undertaken to evaluate the anticancer effect of these quinazolinone derivatives. The quinazolinone derivatives were synthesized as reported earlier. Compounds containing NO(2), OH, OCH(3), or OH and OCH(3) as substituent(s) on the arylideneamino group were named as P(3a), P(3b), P(3c), and P(3d) respectively. Out of these, P(3a) and P(3d) showed better cytotoxic activity than P(3b) and P(3c) on a panel of six cancer cell lines of different origin, namely, B16F10, MiaPaCa-2, HCT116, HeLa, MCF7, and HepG2, though the effect was higher in B16F10, HCT116, and MCF7 cells. P(3a) and P(3d) induced death of B16F10 and HCT116 cells was associated with characteristic apoptotic changes like cell shrinkage, nuclear condensation, DNA fragmentation, and annexin V binding. Also, cell cycle arrest at G1 phase, alteration of caspase-3, caspase-9, Bcl-2 and PARP levels, loss of mitochondrial membrane potential, and enhanced level of cytosolic cytochrome c were observed in treated B16F10 cells. Treatment with multiple doses of P(3a) significantly increased the survival rate of B16F10 tumor bearing BALB/c mice by suppressing the volume of tumor while decreasing microvascular density and mitotic index of the tumor cells.     

Design, synthesis and anticonvulsant activities of novel 1-(substituted/unsubstituted benzylidene)-4-(4-(6,8-dibromo-2-(methyl/phenyl)-4-oxoquinazolin-3(4H)-yl)phenyl) semicarbazide derivatives

Novel quinazolinone derivatives 5a-5n were designed, synthesized and screened for antiepileptic activity using MES and scPTZ seizures tests. Neurotoxicity study was performed by rotorod test. Compounds 5c, 5d, 5g, 5j and 5k were found active in the preliminary screening in MES model and/or scPTZ model. Further all these five compounds were administered to rats, 5c and 5d showed better activity than Phenytoin in oral route. Among all the title compounds tested, the most active one was 5c that revealed protection in MES at a dose of 30 mg/kg (ip) after 0.5 and 4h. This molecule also provided protection in the scPTZ at a dose of 100mg/kg (0.5h) and 300 mg/kg (4h).     

Kinetic mechanism of dopamine transporter interaction with 1-(2-(bis-(4-fluorophenyl)methoxy)ethyl)-4-(3-phenylpropyl)piperazine (GBR 12909)

Interaction of piperazine-based dopamine transporter inhibitor GBR12909 with rat dopamine transporters has been studied by means of competition kinetics analysis, employing [(3)H]PE2I as the reporter ligand. It has been found that GBR12909 is capable of inducing so-called "slow isomerization step" upon binding to DAT, probably consisting of a conformational change in the transporter protein. The mechanism exhibited by GBR12909 appears to be similar to the mechanism of PE2I that has been reported earlier and also confirms previous observations for GBR12783 made by Do-Rego and co-workers using dopamine uptake data. It appears that the isomerization phenomenon previously described for PE2I is not limited to tropane-based DAT inhibitors, but is, in fact, a general property of dopamine transporter protein, similar to "isomerization" process reported previously for G-protein coupled receptors. The rapid first step of association of the GBR 12909 is characterized by the equilibrium constant K(L)=34+/-11nM and the second slow step by k(i)=0.033+/-0.005s(-1).     

Facile route for the synthesis of the iminosugar nucleoside (3R,4R)-1-(pyren-1-yl)-4-(hydroxymethyl)pyrrolidin-3-ol

N-(Pyren-1-yl)-(3R,4S)-4-[(1S,2R)-1,2,3-trihydroxypropyl]pyrrolidin-3-ol (4) was obtained in 36% yield from 3-deoxy-3-C-formyl-1,2:5,6-di-O-isopropylidene-α-d-allofuranose (3) by combined hydrolysis and aminoalkylation reactions with 1-aminopyrene in a one-pot reaction. Cleavage reactions of the exocyclic triol chain in 4 with NaIO₄ and NaBH₄ resulted in iminosugars 7 and 8, which are analogues of the furanose forms of 2-deoxy-d-allose and of 2-deoxy-d-ribose, the latter analogue N-(pyren-1-yl)-(3R,4R)-4-(hydroxymethyl)pyrrolidin-3-ol (8) being formed in 83% yield.     

Potential antitumour and pro-oxidative effects of (E)-methyl 2-(7-chloroquinolin-4-ylthio)-3-(4-hydroxyphenyl) acrylate (QNACR)

Context: Characterization of the pro-oxidant activity of QNACR.

Objectives: Reactive oxygen species (ROS) induce cellular damage and represent unique opportunities to kill malignant cells. In this study, we synthesized and evaluated the new compound, (E)-methyl 2-(7-chloroquinolin-4-ylthio)-3-(4-hydroxyphenyl) acrylate (QNACR) as potential pro-oxidative agent against breast cancer.

Methods: Oxidative stress biomarkers such as ROS, thiobarbuturic acid reactive species (TBARs) and different antioxidant enzyme activities were determined in cell lysates.

Results: QNACR showed cytotoxic and more selective effects to tumour MCF7 cells (IC₅₀ < 25 µM) compared to antitumour controls, inducing ROS and TBARs parallel to inhibitions of catalase (CAT), glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH). Longer exposures to QNACR triggered adaptive effects increasing the overall activities of CAT, glutathione reductase, G6PDH and 6PGDH, but eventually the adaptation changes faded and cells died.

Conclusion: QNACR led to remarkable modifications in the oxidative status of tumour cells, proposing this compound as potential alternative for antitumour therapy.     

Non-thiol farnesyltransferase inhibitors: N-(4-acylamino-3-benzoylphenyl)-3-[5-(4-nitrophenyl)-2-furyl]acrylic acid amides

We have designed the nitrophenylfurylacryl-substituted benzophenone 4f as a non-thiol farnesyltransferase inhibitor utilizing a novel aryl binding site of farnesyltransferase. Variation of the 2-acylamino substituent at the benzophenone core structure of our initial lead 4f yielded several non-thiol farnesyltransferase inhibitors with improved activity. These compounds display activity in the low nanomolar range.     

Dual DAT/sigma1 receptor ligands based on 3-(4-(3-(bis(4-fluorophenyl)amino)propyl)piperazin-1-yl)-1-phenylpropan-1-ol

Ester analogs of (+/-)3-(4-(3-(bis(4-fluorophenyl)amino)propyl)piperazin-1-yl)-1-phenylpropan-1-ol were synthesized and evaluated for binding at DAT, SERT, NET, and sigma1 receptors, and compared to GBR 12909 and several known sigma1 receptor ligands. Most of these compounds demonstrated high affinity (K(i)=4.3-51 nM) and selectivity for the DAT among the monoamine transporters. S- and R-1-(4-(3-(bis(4-fluorophenyl)amino)propyl)piperazin-1-yl)-3-phenylpropan-2-ol were also prepared wherein modest enantioselectivity was demonstrated at the DAT. However, no enantioselectivity at sigma1 receptors was observed and most of the ester analogs of the more active S-enantiomer showed comparable binding affinities at both DAT and sigma1 receptors with a maximal 16-fold DAT/sigma1 selectivity.     

Reversal of multidrug resistance by 4-chloro-N-(3-((E)-3-(4-hydroxy-3-methoxyphenyl)acryloyl)phenyl)benzamide through the reversible inhibition of P-glycoprotein

Overexpression of P-glycoprotein (P-gp) is one of the major obstacles to successful cancer chemotherapy. In this study, we examined the ability of 4-chloro-N-(3-((E)-3-(4-hydroxy-3-methoxyphenyl)acryloyl)phenyl)benzamide (C-4) to reverse multidrug resistance (MDR) in P-gp expressing KBV20C cells. Treatment of KBV20C cells with C-4 led to a dramatic increase in paclitaxel- or vincristine-induced cytotoxicity without any cytotoxicity by itself. In parallel, C-4 treatment caused an increase in apoptotic cell death by paclitaxel or vincristine. Furthermore, C-4 treatment significantly increases in intracellular accumulation of fluorescent P-gp substrate rhodamine 123, indicating that C-4 treatment leads to reversal of the MDR phenotype resulting from an increased accumulation of anticancer drugs by inhibiting drug efflux function of P-gp. This notion is further supported by the observation that C-4 treatment potentiates paclitaxel-induced G(2)/M arrest of the cell cycle. In addition, the drug efflux function of P-gp was reversibly inhibited by C-4 treatment, while the expression level of P-gp was not affected. Collectively, our results describe the potential of C-4 to reverse the P-gp-mediated MDR phenotype through reversible inhibition of P-gp function, which may make it an attractive new agent for the chemosensitization of cancer cells.     

Synthesis and bioactivity studies on new 4-(3-(4-Substitutedphenyl)-3a,4-dihydro-3H-indeno[1,2-c]pyrazol-2-yl) benzenesulfonamides

A series of new 4-(3-(4-substitutedphenyl)-3a,4-dihydro-3H-indeno[1,2-c]pyrazol-2-yl) benzenesulfonamides (7–12) was synthesized starting from 2-(4-substitutedbenzylidene)-2,3-dihydro-1H-inden-1-one (1–6) and 4-hydrazinobenzenesulfonamide. The substituted benzaldehydes from which the key intermediate was prepared by introducing 2- or 4-substituents such as fluorine, hydroxy, methoxy, or the 3,4,5-trimethoxy moieties. The compounds were tested for their cytotoxicity, tumor-specificity and potential as carbonic anhydrase (CA, EC 4.2.1.1) inhibitors. The 3,4,5-trimethoxy and the 4-hydroxy derivatives showed interesting cytotoxic activities, which may be crucial for further anti-tumor activity studies, whereas some of these sulfonamides strongly inhibited both human (h) cytosolic isoforms hCA I and II.     

(3R)-4-[(3R)-3-Amino-4-(2,4,5-trifluorophenyl)butanoyl]-3-(2,2,2-trifluoroethyl)-1,4-diazepan-2-one, a selective dipeptidyl peptidase IV inhibitor for the treatment of type 2 diabetes

Replacement of the triazolopiperazine ring of sitagliptin (DPP-4 IC(50)=18nM) with 3-(2,2,2-trifluoroethyl)-1,4-diazepan-2-one gave dipeptidyl peptidase IV (DPP-4) inhibitor 1 which is potent (DPP-4 IC(50)=2.6nM), selective, and efficacious in an oral glucose tolerance test in mice. It was selected for extensive preclinical development as a potential back-up candidate to sitagliptin.     

Synthesis and Biological Evaluation of 3-Chloro-4-(D-Ribofuranosyl)-Pyridine and 3-(D-Ribofuranosyl)-2- Pyridone

Abstract

Condensation of 2-fluoro-3-lithio pyridine and 3-chloro-4-lithio pyridine with 2,4:3,5-di-O-benzylidene-alde-hydo-D-ribose gives the corresponding D-allo- and D-altro-addition products. These were converted into the corresponding mesylates and cyclized to the ribofuranosyl nucleosides with an overall yield of 60–70 %. Both nucleosides did not show any inhibitory effect on L-₁₂₁₀-cells.     

Novel retinoic acid 4-hydroxylase (CYP26) inhibitors based on a 3-(1H-imidazol- and triazol-1-yl)-2,2-dimethyl-3-(4-(phenylamino)phenyl)propyl scaffold

Retinoic acid (RA), the biologically active metabolite of vitamin A, is used medicinally for the treatment of hyperproliferative diseases including dermatological conditions and cancer. The antiproliferative effects of RA have been well documented as well as the limitations owing to toxicity and the development of resistance to RA therapy. RA metabolism inhibitors (RAMBAs or CYP26 inhibitors) are attracting increasing interest as an alternative method for enhancing endogenous levels of retinoic acid in the treatment of hyperproliferative disease. Here the synthesis and inhibitory activity of novel 3-(1H-imidazol- and triazol-1-yl)-2,2-dimethyl-3-(4-(phenylamino)phenyl)propyl derivatives in a MCF-7 CYP26A1 microsomal assay are described. The most promising inhibitor methyl 2,2-dimethyl-3-(4-(phenylamino)phenyl)-3-(1H-1,2,4-triazol-1-yl)propanoate (6) exhibited an IC(50) of 13 nM (compared with standards Liarozole IC(50) 540 nM and R116010 IC(50) 10 nM) and was further evaluated for CYP selectivity using a panel of CYP with >100-fold selectivity for CYP26 compared with CYP1A2, 2C9 and 2D6 observed and 15-fold selectivity compared with CYP3A4. The results demonstrate the potential for further development of these potent inhibitors.     

Novel and potent 3-(2,3-dichlorophenyl)-4-(benzyl)-4H-1,2,4-triazole P2X7 antagonists

Structure-activity relationship (SAR) studies were conducted around early tetrazole-based leads 3 and 4. Replacements for the tetrazole core were investigated and the pendant benzyl substitution was reoptimized with a triazole isostere. Triazole-based P2X(7) antagonists were identified with similar potency to the lead compound 4 but with improved physiochemical properties. Compound 12 was active in a rat model of neuropathic pain.     

Bleaching activity of 4-phenyl-3-(substituted benzylthio)-4H-1,2,4-triazoles

A variety of 4-aryl- and 4-alkyl-3-(substituted benzylthio)-4H-1,2,4-triazoles were prepared and evaluated for their bleaching activity by the lettuce seedling test. Among the series of tested compounds, 4-(3-fluorophenyl)-3-(4-trifluoromethylbenzylthio)-4H-1,2,4-triazole (39) exhibited the highest bleaching activity, causing complete bleaching symptoms at 10 microM. In the dark condition, compound 39 inhibited the formation of such carotenoids as beta-carotene, violaxanthin, neoxanthin and lutein, resulting in the formation of zeta-carotene, phytoene, phytofluene and beta-zeacarotene, which were not detected in the untreated control. Treatment by compound 39 at 50 microM resulted in the amount of accumulated zeta-carotene being seven-fold higher than that of phytoene, phytofluene and beta-zeacarotene. These results suggest that compound 39 might have interfered with desaturation, especially zeta-carotene desaturation, during carotenoid biosynthesis.