Chemoenzymatic synthesis of a series of 4-substituted glutamate analogues and pharmacological characterization at human glutamate transporters subtypes 1-3

A series of nine L-2,4-syn-4-alkylglutamic acid analogues (1a-i) were synthesized in high yield and high enantiomeric excess (>99% ee) from their corresponding 4-substituted ketoglutaric acids (2a-i), using the enzyme aspartate aminotransferase (AAT) from pig heart or E. coli. The synthesized compounds were evaluated as potential ligands for the glutamate transporters EAAT1, EAAT2, and EAAT3 (excitatory amino acid transporter, subtypes 1-3) in the FLIPR membrane potential (FMP) assay. We found a distinct change in the pharmacological profile when the 4-methyl group (compound 1a, an EAAT1 substrate and EAAT2,3 inhibitor) was extended to a 4-ethyl group, compound 1b, as this analogue is an inhibitor at all three subtypes, EAAT1-3. Furthermore, we conclude that both large and bulky hydrophobic substituents in the 4-position of L-2,4-syn Glu are allowed by all three glutamate transporter subtypes EAAT1-3 while maintaining inhibitory activity.     

Stereoselective chemoenzymatic synthesis of the four stereoisomers of l-2-(2-carboxycyclobutyl)glycine and pharmacological characterization at human excitatory amino acid transporter subtypes 1, 2, and 3

The four stereoisomers of l-2-(2-carboxycyclobutyl)glycine, l-CBG-I, l-CBG-II, l-CBG-III, and l-CBG-IV, were synthesized in good yield and high enantiomeric excess, from the corresponding cis and trans-2-oxalylcyclobutanecarboxylic acids 5 and 6 using the enzymes aspartate aminotransferase (AAT) and branched chain aminotransferase (BCAT) from Escherichia coli. The four stereoisomeric compounds were evaluated as potential ligands for the human excitatory amino acid transporters, subtypes 1, 2, and 3 (EAAT1, EAAT2, and EAAT3) in the FLIPR membrane potential assay. While the one trans-stereoisomer, l-CBG-I, displayed weak substrate activity at all three transporters, EAAT1-3, we found a particular pharmacological profile for the other trans-stereoisomer, l-CBG-II, which displayed EAAT1 substrate activity and inhibitory activity at EAAT2 and EAAT3. Whereas l-CBG-III was found to be a weak inhibitor at all three EAAT subtypes, the other cis-stereoisomer l-CBG-IV was a moderately potent inhibitor with 20-30-fold preference for EAAT2/3 over EAAT1.     

Design,synthesis, and evaluation of novel (E)-N'-(3-allyl-2-hydroxy)benzylidene-2-(4-oxoquinazolin-3(4H)-yl)acetohydrazides as antitumor agents

In our continuing search for novel small-molecule anticancer agents, we designed and synthesized a series of novel (E)-N'-(3-allyl-2-hydroxy)benzylidene-2-(4-oxoquinazolin-3(4H)-yl)acetohydrazides ( 5 ), focusing on the modification of substitution in the quinazolin-4(3H)-one moiety. The biological evaluation showed that all 13 designed and synthesized compounds displayed significant cytotoxicity against three human cancer cell lines (SW620, colon cancer; PC-3, prostate cancer; NCI-H23, lung cancer). The most potent compound 5l displayed cytotoxicity up to 213-fold more potent than 5-fluorouracil and 87-fold more potent than PAC-1, the first procaspase-activating compound. Structure–activity relationship analysis revealed that substitution of either electron-withdrawing or electron-releasing groups at positions 6 or 7 on the quinazolin-4(3H)-4-one moiety increased the cytotoxicity of the compounds, but substitution at position 6 seemed to be more favorable. In the caspase activation assay, compound 5l was found to activate the caspase activity by 291% in comparison to PAC-1, which was used as a control. Further docking simulation also revealed that this compound may be a potent allosteric inhibitor of procaspase-3 through chelation of the inhibitory zinc ion. Physicochemical and ADMET calculations for 5l provided useful information of its suitable absorption profile and some toxicological effects that need further optimization to be developed as a promising anticancer agent.     

WAY-855 (3-amino-tricyclo[2.2.1.02.6]heptane-1,3-dicarboxylic acid): a novel, EAAT2-preferring, nonsubstrate inhibitor of high-affinity glutamate uptake

The pharmacological profile of a novel glutamate transport inhibitor, WAY-855 (3-amino-tricyclo[2.2.1.0(2.6)]heptane-1,3-dicarboxylic acid), on the activity of the human forebrain glutamate transporters EAAT1, EAAT2 and EAAT3 expressed in stable mammalian cell lines and in Xenopus laevis oocytes is presented. WAY-855 inhibited glutamate uptake mediated by all three subtypes in a concentration-dependent manner, with preferential inhibition of the CNS-predominant EAAT2 subtype in both cells and oocytes. IC50 values for EAAT2 and EAAT3 inhibition in cells were 2.2 and 24.5 microM, respectively, while EAAT1 activity was inhibited by 50% at 100 microM (IC50 values determined in oocytes were 1.3 microM (EAAT2), 52.5 microM (EAAT3) and 125.9 microM (EAAT1)). Application of WAY-855 to EAAT-expressing oocytes failed to induce a transporter current, and the compound failed to exchange with accumulated [3H]d-aspartate in synaptosomes consistent with a nonsubstrate inhibitor. WAY-855 inhibited d-aspartate uptake into cortical synaptosomes by a competitive mechanism, and with similar potency to that observed for the cloned EAAT2. WAY-855 failed to agonise or antagonise ionotropic glutamate receptors in cultured hippocampal neurones, or the human metabotropic glutamate receptor subtype 4 expressed in a stable cell line. WAY-855 represents a novel structure in glutamate transporter pharmacology, and exploration of this structure might provide insights into the discrimination between EAAT2 and other EAAT subtypes.     

Synthesis and biological evaluation of novel analogues of the pan class I phosphatidylinositol 3-kinase (PI3K) inhibitor 2-(difluoromethyl)-1-[4,6-di(4-morpholinyl)-1,3,5-triazin-2-yl]-1H-benzimidazole (ZSTK474)

A structure-activity relationship (SAR) study of the pan class I PI 3-kinase inhibitor 2-(difluoromethyl)-1-[4,6-di(4-morpholinyl)-1,3,5-triazin-2-yl]-1H-benzimidazole (ZSTK474) identified substitution at the 4 and 6 positions of the benzimidazole ring as having significant effects on the potency of substituted derivatives. The 6-amino-4-methoxy analogue displayed a greater than 1000-fold potency enhancement over the corresponding 6-aza-4-methoxy analogue against all three class Ia PI 3-kinase enzymes (p110α, p110β, and p110δ) and also displayed significant potency against two mutant forms of the p110α isoform (H1047R and E545K). This compound was also evaluated in vivo against a U87MG human glioblastoma tumor xenograft model in Rag1(-/-) mice, and at a dose of 50 mg/kg given by ip injection at a qd × 10 dosing schedule it dramatically reduced cancer growth by 81% compared to untreated controls.     

(3S,4S)-3-苄氧羰基氨基-4-羟甲基-2-氧代氮杂环丁烷-1-磺酸四丁基铵氨甲酰化的新方法

目的研究氨甲酰化(3S,4S)-3-苄氧羰基氨基-4-羟甲基-2-氧代氮杂环丁烷-1-磺酸四丁基铵(1)的新方法。方法以化合物1为原料,二氯甲烷为溶剂,经氯磺酰异氰酸酯酰化、亚硫酸钠水溶液脱氯磺酰基,再经阳离子交换树脂得目标化合物(3)。结果所得化合物经1HNMR、IR、旋光和元素分析确证。结论所选方法用于化合物1氨甲酰化较理想。     

Synthesis and anti-diabetic activity of （RS）-2-ethoxy-3-{4-[2-（4-trifluoro-methanesulfonyloxy-phenyl）-ethoxy]-phenyl}-propionic acid

AIM: To synthesize and study the anti-diabetic activity of (RS)-2-ethoxy-3-{4-[2-(4-trifluoromethanesulfonyloxy-phenyl)-ethoxy]-phenyl}-propionic acid (compound I). METHODS: Compound I was prepared in 6 steps, using 4-(2-hydroxy-ethyl)-phenol as the starting material. The in vitro selectivity and potency of target compound I, rosiglitazone and WY-14643 on human PPARalpha and PPARgamma were determined in reporter gene assays. In vivo, rosiglitazone and compound I were administered orally to KK(Ay) mice for 14 d. Insulin tolerance tests and oral glucose tolerance tests were performed on the 10th and 14th day of treatment, respectively. At the end of the treatment, sera were collected for biochemical analysis. RESULTS: In vitro, compound I significantly activated both PPARalpha and PPARgamma. In vivo, compound I corrected the impaired insulin and glucose tolerance of KK(Ay) mice, and produced a significant reduction in plasma triglyceride levels after 14 d of treatment. The effect produced was significant compared with the control group. CONCLUSION: Both in vitro and in vivo anti-diabetic activity studies for compound I were conducted and the data suggest that this compound is a potentially effective anti-diabetic agent.     

2-Acetylamino-3-[4-(2-acetylamino-2-carboxyethylsulfanylcarbonylamino)- phenylcarbamoylsulfanyl]propionic acid and its derivatives as a novel class of glutathione reductase inhibitors

Glutathione reductase (GR) catalyzes the reduction of oxidized glutathione to reduced glutathione. The enzyme is an attractive target for the development of antimalarial agents, agents to decrease malarial drug resistance and anticancer agents. In addition, inhibition of the enzyme has been employed as a tool in research for various purposes. In this paper, we present a rational design of 2-acetylamino-3-[4-(2-acetylamino-2-carboxyethylsulfanylcarbonylamino)phenylcarbamoylsulfanyl]propionic acid and its derivatives as irreversible GR inhibitors. The K(i) and k(inact) values of 2-acetylamino-3-[4-(2-acetylamino-2-carboxyethylsulfanylcarbonylamino)phenylcarbamoylsulfanyl]propionic acid, the most potent derivative of the series, are 88 muM and 0.1 min(-1), respectively. Although the K(i) value of the inhibitor is in the micromolar range, it is more potent than N,N-bis(2-chloroethyl)-N-nitrosourea, which is currently the most commonly employed irreversible GR inhibitor with a reported IC(50) value of 646 microM. Additional attractive features of the inhibitor include its ready availability through a one-step synthesis and good solubility in both organic and aqueous solutions.     

Identification of 5-(3-(methylsulfonyl)phenyl)-3-(4-(methylsulfonyl)phenyl)-3H-imidazo[4,5-b]pyridine as novel orally bioavailable and metabolically stable antimalarial compound for further exploration

Malaria continues to be a significant public health problem threatened by the emergence and spread of resistance to artemisinin-based combination therapies and marked half a million deaths in 2016. A new imidazopyridine chemotype has been envisaged through scaffold-hopping approach combined with docking studies for putative-binding interactions with Plasmodium falciparum phosphatidylinositol-4-kinase (PfPI4K) target. The docking results steered to the synthesis of compound 1 [5-(3-(methylsulfonyl)phenyl)-3-(4-(methylsulfonyl)phenyl)-3H-imidazo[4,5-b]pyridine] followed by the in vitro screening for antiplasmodial activity and ADME-PK studies. Combined with potent antimalarial activity of compound 1 (Pf3D7 IC₅₀ = 29 nM) with meager in vitro intrinsic clearance, moderate plasma-protein binding, and acceptable permeability, compound 1 displayed sustained exposure and high oral bioavailability in mice and can thus have the potential as next generation PI4K inhibitor for in vivo studies.     

Transporters for L-glutamate: an update on their molecular pharmacology and pathological involvement

L-Glutamate (Glu) is the major excitatory neurotransmitter in the mammalian CNS and five types of high-affinity Glu transporters (EAAT1-5) have been identified. The transporters EAAT1 and EAAT2 in glial cells are responsible for the majority of Glu uptake while neuronal EAATs appear to have specialized roles at particular types of synapses. Dysfunction of EAATs is specifically implicated in the pathology of neurodegenerative conditions such as amyotrophic lateral sclerosis, epilepsy, Huntington's disease, Alzheimer's disease and ischemic stroke injury, and thus treatments that can modulate EAAT function may prove beneficial in these conditions. Recent advances have been made in our understanding of the regulation of EAATs, including their trafficking, splicing and post-translational modification. This article summarises some recent developments that improve our understanding of the roles and regulation of EAATs.     

Inhibition of L-type Cav1.2 Ca2+ channels by 2,(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002) and 2-[1-(3-dimethyl-aminopropyl)-5-methoxyindol-3-yl]-3-(1H-indol-3-yl) maleimide (Go6983)

Phosphatidylinositol 3-kinase (PI3-K) is involved in physiological processes of cellular proliferation and inflammation and, as postulated recently, in the regulation of L-type Ca(2+) channels. The latter conclusion arose in part from the inhibitory action of the compound 2,(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002), which has been established as a selective PI3-K inhibitor (IC(50) = 1.4 microM). Herein we show, however, that LY294002 and an inhibitor of protein kinase C (PKC), 2-[1-(3-dimethylaminopropyl)-5-methoxyindol-3-yl]-3-(1H-indol-3-yl) maleimide (Go6983), act as direct Ca(2+)-channel inhibitors, with IC(50) values of approximately 20 and 10 microM, respectively. Because both drugs are commonly used at concentrations of approximately 10 microM or higher, the interpretation of such experiments is questionable with respect to a regulatory action of PI3-K or PKC on L-type Ca(2+) channels.     

Identification of 2-(4-benzyloxyphenyl)-N- [1-(2-pyrrolidin-1-yl-ethyl)-1H-indazol-6-yl]acetamide, an orally efficacious melanin-concentrating hormone receptor 1 antagonist for the treatment of obesity

Optimization of a high-throughput screening hit against melanin-concentrating hormone receptor 1 (MCHr1) led to the discovery of 2-(4-benzyloxy-phenyl)-N-[1-(2-pyrrolidin-1-yl-ethyl)-1H-indazol-6-yl]acetamide (7a). This compound was found to be a high-affinity ligand for MCHr1 and a potent inhibitor of MCH-mediated Ca(2+) release, showed good plasma and CNS exposure upon oral dosing in diet-induced obese mice, and is the first reported MCHr1 antagonist that is efficacious upon oral dosing in a chronic model of weight loss.     

The structure of (S)-(-)-4-(2-benzimidazolyl)-4-hydroxybutyric acid formed during mammalian metabolism of the fungicide 2-(2-furyl)benzimidazole

During metabolism of the fungicide 2-(2-furyl)benzimidazole (FB) in mammals, an optically active compound, metabolite A, was isolated. This compound, a principal metabolite in the biological degradation of FB, was isolated from the urine of horse and dog. When studied by IR, NMR, MS, CD and electrophoretic techniques, the metabolite proved to be the zwitterionic form of (S)-(-)-4-(2-benzimidazolyl)-4-hydroxybutyric acid. The synthesized optical active compound was in every respect identical with metabolite A. The suggested structure has been completely verified by the current investigation of its crystal structure, based on single crystal diffraction data collected at the synchrotron MAX II in Lund, Sweden. In an earlier determination, a related compound, 3-benzimidazolylpropionic acid (Ercan et al. 1996) was suggested to be non-zwitterionic. The present studies have shown that the latter compound too is zwitterionic and that the conclusions presented were apparently based on some erroneously proposed hydrogen positions.     

Design and synthesis of 3-(4-chlorophenyl)-2-(2-(4-substituted)-2-oxoethylthio)quinazolin-4(3H)-one as antihistamine agents

A series of novel 3-(4-chlorophenyl)-2-(2-(4-substituted)-2-oxoethylthio)quinazolin-4(3H)-one was synthesized by the reaction of 2-(3-(4-chlorophenyl)-4-oxo-3,4-dihydroquinazolin-2-ylthio)acetyl chloride with various amines. The starting material, (3-(4-chlorophenyl)-4-oxo-3,4-dihydroquinazolin-2-ylthio)acetyl chloride was synthesized from 4-chloroaniline by a multistep synthesis. All the title compounds were tested for their in vivo H₁-antihistaminic activity on conscious guinea pigs at the dose level of 10 mg/kg using chlorpheniramine maleate as the reference standard. The results of the biological activity indicate that the test compounds protected the animals from histamine-induced bronchospasm significantly. Compound 3-(4-chlorophenyl)-2-(2-(4-methylpiperazin-1-yl)-2-oxoethylthio)quinazolin-4(3H)-one (1) emerged as the most potent compound of the series (71.13 % protection) when compared to the reference standard chlorpheniramine maleate (70.09 % protection). Interestingly, compound A1 shows negligible sedation (12 %) compared to chlorpheniramine maleate (32 %). Therefore, compound A1 can serve as the lead molecule for further development.     

Characterization of novel aryl-ether, biaryl, and fluorene aspartic acid and diaminopropionic acid analogs as potent inhibitors of the high-affinity glutamate transporter EAAT2

In this study, we describe the pharmacological characterization of novel aryl-ether, biaryl, and fluorene aspartic acid and diaminopropionic acid analogs as potent inhibitors of EAAT2, the predominant glutamate transporter in forebrain regions. The rank order of potency determined for the inhibition of human EAAT2 was N(4)-[4-(2-bromo-4,5-difluorophenoxy)phenyl]-L-asparagine (WAY-213613) (IC(50) = 85 +/- 5 nM) > N(4)-(2'-methyl-1,1'-biphenyl-4-yl)-L-asparagine (WAY-213394) (IC(50) = 145 +/- 22 nM) = N(4)-[7-(trifluoromethyl)-9H-fluoren-2-yl]-L-asparagine (WAY-212922) (IC(50) = 157 +/- 11 nM) = 3-{[(4'-chloro-2-methyl-1,1'-biphenyl-4-yl)carbonyl]amino}-L-alanine (WAY-211686) (IC(50) = 190 +/- 10 nM). WAY-213613 was the most selective of the compounds examined, with IC(50) values for inhibition of EAAT1 and EAAT3 of 5 and 3.8 microM, respectively, corresponding to a 59- and 45-fold selectivity toward EAAT2. An identical rank order of potency [WAY-213613 (35 +/- 7 nM) > WAY-213394 (92 +/- 13 nM) = WAY-212922 (95 +/- 8 nM) = WAY-211686 (101 +/- 20 nM)] was observed for the inhibition of glutamate uptake in rat cortical synaptosomes, consistent with the predominant contribution of EAAT2 to this activity. Kinetic studies with each of the compounds in synaptosomes revealed a competitive mechanism of inhibition. All compounds were determined to be nonsubstrates by evaluating both the stimulation of currents in EAAT2-injected oocytes and the heteroexchange of d-[(3)H]aspartate from cortical synaptosomes. WAY-213613 represents the most potent and selective inhibitor of EAAT2 identified to date. Taken in combination with its selectivity over ionotropic and metabotropic glutamate receptors, this compound represents a potential tool for the further elucidation of EAAT2 function.     

Characterization and effects of methyl-2- (4-aminophenyl)-1, 2-dihydro-1-oxo-7- (2-pyridinylmethoxy)-4-(3,4, 5-trimethoxyphenyl)-3-isoquinoline carboxylate sulfate (T-1032), a novel potent inhibitor of cGMP-binding cGMP-specific phosphodiesterase (PDE5)

An isoquinolone derivative, methyl-2-(4-aminophenyl)-1, 2-dihydro-1-oxo-7-(2-pyridinylmethoxy)-4-(3,4, 5-trimethoxyphenyl)-3-isoquinoline carboxylate sulfate (T-1032), was found to be a novel potent inhibitor of cyclic GMP (cGMP)-binding cGMP-specific phosphodiesterase (PDE5). We investigated the inhibitory effects of T-1032 on six PDE isozymes isolated from canine tissues. T-1032 specifically inhibited the hydrolysis of cGMP by PDE5 partially purified from canine lung, at a low concentration (IC(50) = 1.0 nM, K(i) = 1.2 nM), in a competitive manner. In contrast, the IC(50) values of T-1032 for PDE1, PDE2, PDE3, and PDE4 were more than 1 microM. T-1032 also inhibited PDE6 from canine retina with an IC(50) of 28 nM, which is of the same order of magnitude as the IC(50) of sildenafil. cGMP hydrolytic activities of two alternative splice variants of canine PDE5 expressed in COS-7 cells were inhibited by this compound to a similar extent. T-1032 increased the intracellular concentration of cGMP in cultured rat vascular smooth muscle cells in the presence and absence of C-type natriuretic peptide, an activator of membrane-bound guanylate cyclase, whereas the compound did not change cyclic AMP levels. These data indicated that T-1032, which belongs to a new structural class of PDE5 inhibitors, is a potent and selective PDE5 inhibitor. This compound may be useful in pharmacological studies to examine the role of a cGMP/PDE5 pathway in tissues.     

Design, synthesis, and potential CNS activity of some new bioactive 1-(4-substituted-phenyl)-3-(4-oxo-2-methyl-4H-quinazolin-3-yl)-urea

Twelve new 1-(4-substituted-phenyl)-3-(4-oxo-2-methyl-4H-quinazolin-3-yl)-urea were synthesized and screened for anticonvulsant, CNS depressant, and sedative-hypnotic activity. After i.p. injection to mice at doses of 30, 100, and 300 mg/kg body weight 2,3-Disubstituted-quinazolin-4(3H)-one were examined in the maximal electroshock-induced seizures (MES) and subcutaneous pentylenetetrazole (scPTZ) induced seizure models in mice. Spectroscopic data and elemental analysis were consistent with the newly synthesized compounds. The neurotoxicity was assessed using the rotorod method. M3, M4, and M10 were found to be active in both MES screen and scPTZ screen at 0.5 h. All except M11 showed more than 44% decrease in locomotor activity after 1 h of compound administration via actophotometer screen. CNS-depressant activity screened with the help of the forced swim method resulted into some potent compounds. Except for M6 and M11 other tested compounds were found to exhibit potent CNS depressants activity as indicated by increased immobility time. It can be concluded that newly synthesized compounds possessed sedative-hypnotic and CNS depressant activities.     

1-[4-(3-Phenylalkyl)phenyl]-2-aminopropanes as 5-HT(2A) partial agonists

Phenylalkylamines such as 1-(4-bromo-2, 5-dimethoxyphenyl)-2-aminopropane (DOB; 1a) and its corresponding iodo derivative DOI (2) are commonly used 5-HT(2) serotonin agonists. Previous studies have established that the 2,5-dimethoxy substitution pattern found in these compounds is optimal for high affinity at 5-HT(2A) receptors and that substituents at the 4-position can modulate affinity over a wide range. We have previously shown, however, that when the 4-position is substituted with a 3-phenylpropyl substituent (i.e., 3), the compound binds with an affinity comparable to that of 1a but that it possesses 5-HT(2A) antagonist character. The present study examined the structure-affinity relationships of 3, and the results were very much unexpected. That is, the 2,5-dimethoxy substitution pattern of 3 is not required for high affinity. Either of the two methoxy groups can be removed without untoward effect on affinity, and relocation of the methoxy substituents actually enhances affinity by as much as an order of magnitude. None of the compounds displayed more than 20-fold selectivity for 5-HT(2A) over 5-HT(2C) receptors. In addition, several were demonstrated to act as 5-HT(2A) partial agonists. As such, the results of this study suggest that the structure-affinity relationships of phenylalkylamines as 5-HT(2A) ligands now be reinvestigated in greater detail.     

Inactivation of gamma-aminobutyric acid aminotransferase by (S,E)-4-amino-5-fluoropent-2-enoic acid and effect on the enzyme of (E)-3-(1-aminocyclopropyl)-2-propenoic acid

(S,E)-4-Amino-5-fluoropent-2-enoic acid (6) is synthesized in six steps starting from the known gamma-aminobutyric acid aminotransferase (gamma-Abu-T) inactivator, (S)-4-amino-5-fluoropentanoic acid (1). Compound 6 is a mechanism-based inactivator of gamma-Abu-T: time-dependent inactivation is saturatable and protected by substrate; thiols do not protect the enzyme from inactivation; no enzyme activity returns upon dialysis. This compound (6) binds 50 times more tightly to gamma-Abu-T than does the saturated analogue (1). No transamination of 6 occurs prior to inactivation. However, five molecules of 6 are required to inactivate the enzyme with concomitant release of five fluoride ions. Therefore, four molecules are being converted to product for each inactivation event. (E)-3-(1-Aminocyclopropyl)-2-propenoic acid is synthesized in seven steps from 1-aminocyclopropanecarboxylic acid. It is prepared as a cyclopropyl derivative of the proposed intermediate in the inactivation of gamma-Abu-T by 6. The cyclopropyl derivative, however, is a noncompetitive inhibitor and does not inactivate the enzyme. This study shows the usefulness and hazards of incorporation of a trans double bond into potential gamma-Abu-T inactivators.     

The discovery of (2R,4R)-N-(4-chlorophenyl)-N- (2-fluoro-4-(2-oxopyridin-1(2H)-yl)phenyl)-4-methoxypyrrolidine-1,2-dicarboxamide (PD 0348292), an orally efficacious factor Xa inhibitor

Herein, we report the discovery of novel, proline-based factor Xa inhibitors containing a neutral P1 chlorophenyl pharmacophore. Through the additional incorporation of 1-(4-amino-3-fluoro-phenyl)-1H-pyridin-2-one 22, as a P4 pharmacophore, we discovered compound 7 (PD 0348292). This compound is a selective, orally bioavailable, efficacious FXa inhibitor that is currently in phase II clinical trials for the treatment and prevention of thrombotic disorders.