Discovery of 3-(3-cyano-4-pyridyl)-5-(4-pyridyl)-1,2,4-triazole,FYX-051-a xanthine oxidoreductase inhibitor for the treatment of hyperuricemia

Our previous study identified 2-[2-(2-methoxy-ethoxy)-ethoxy]-5-[5-(2-methyl-4-pyridyl)-1H-[1,2,4]triazol-3-yl]-benzonitrile (2) as a safe and potent xanthine oxidoreductase (XOR) inhibitor for the treatment of hyperuricemia. Here, we synthesized a series of 3,5-dipyridyl-1,2,4-triazole derivatives and, in particular, examined their in vivo activity in lowering the serum uric acid levels in rats. As a result, we identified 3-(3-cyano-4-pyridyl)-5-(4-pyridyl)-1,2,4-triazole (FYX-051, compound 39) to be one of the most potent XOR inhibitors; it exhibited an extremely potent in vivo activity, weak CYP3A4-inhibitory activity and a better pharmacokinetic profile than compound 2. Compound 39 is currently being evaluated in a phase 2 clinical trial.     

Chroman and tetrahydroquinoline ureas as potent TRPV1 antagonists

Novel chroman and tetrahydroquinoline ureas were synthesized and evaluated for their activity as TRPV1 antagonists. It was found that aryl substituents on the 7- or 8-position of both bicyclic scaffolds imparted the best in vitro potency at TRPV1. The most potent chroman ureas were assessed in chronic and acute pain models, and compounds with the ability to cross the blood-brain barrier were shown to be highly efficacious. The tetrahydroquinoline ureas were found to be potent CYP3A4 inhibitors, but replacement of bulky substituents at the nitrogen atom of the tetrahydroisoquinoline moiety with small groups such as methyl can minimize the inhibition.     

Synthesis,SAR study,and biological evaluation of a series of piperazine ureas as fatty acid amide hydrolase (FAAH) inhibitors

A series of piperazine ureas was designed, synthesized, and evaluated for their potential as novel orally available fatty acid amide hydrolase (FAAH) inhibitors that are therapeutically effective against pain. We carried out an optimization study of the lead compound 3 to improve its DMPK profile as well as in vitro potency. We identified the thiazole compound 60j with potent inhibitory activity, high brain permeability, and good bioavailability. Compound 60j showed a potent and dose-dependent anti-nociceptive effect in the acetic acid-induced writhing test in mice.     

Monoamine oxidase inhibitory properties of optical isomers and N-substituted derivatives of 4-methylthioamphetamine

(+/-)-4-Methylthioamphetamine (MTA) was resolved into its enantiomers, and a series of N-alkyl derivatives of the parent compound, as well as its alpha-ethyl analogue, were prepared. The monoamine oxidase (MAO) inhibitory properties of these substances were evaluated in vitro, using a crude rat brain mitochondrial suspension as the source of enzyme. All compounds produced a selective, reversible and concentration-related inhibition of MAO-A. (+)-MTA proved to be the most potent inhibitor studied, while all the other derivatives were less active than the parent compound, with (-)-MTA being about 18 times less potent than the (+) isomer. The analysis of structure-activity relationships indicates that the introduction of alkyl substituents on the amino group of MTA leads to a reduction in the potency of the derivatives as MAO-A inhibitors, an effect which increases with the size of the substituent.     

Biologically active ester derivatives as potent inhibitors of the soluble epoxide hydrolase

Substituted ureas with a carboxylic acid ester as a secondary pharmacophore are potent soluble epoxide hydrolase (sEH) inhibitors. Although the ester substituent imparts better physical properties, such compounds are quickly metabolized to the corresponding less potent acids. Toward producing biologically active ester compounds, a series of esters were prepared and evaluated for potency on the human enzyme, stability in human liver microsomes, and physical properties. Modifications around the ester function enhanced in vitro metabolic stability of the ester inhibitors up to 32-fold without a decrease in inhibition potency. Further, several compounds had improved physical properties.     

Trihalobenzocycloheptapyridine analogues of Sch 66336 as potent inhibitors of farnesyl protein transferase

SCH 66336 is a trihalo tricyclic compound that is currently undergoing Phase II clinical trials for the treatment of solid tumors. Modifications of SCH 66336 by incorporating such groups as amides, acids, esters, ureas and lactams off the first or the distal piperidine (from the tricycle) provided potent FPT inhibitors some of which exhibited good cellular activity. A number of these compounds incorporate properties that might improve pharmacokinetic stability of these inhibitors by virtue of their increased solubility or by their change in log P.     

Discovery and evaluation of 3-phenyl-1H-5-pyrazolylamine-based derivatives as potent, selective and efficacious inhibitors of FMS-like tyrosine kinase-3 (FLT3)

Preclinical investigations and early clinical trial studies suggest that FLT3 inhibitors offer a viable therapy for acute myeloid leukemia. However, early clinical data for direct FLT3 inhibitors provided only modest results because of the failure to fully inhibit FLT3. We have designed and synthesized a novel class of 3-phenyl-1H-5-pyrazolylamine-derived compounds as FLT3 inhibitors which exhibit potent FLT3 inhibition and high selectivity toward different receptor tyrosine kinases. The structure-activity relationships led to the discovery of two series of FLT3 inhibitors, and some potent compounds within these two series exhibited comparable potency to FLT3 inhibitors sorafenib (3) and ABT-869 (4) in both wt-FLT3 enzyme inhibition and FLT3-ITD inhibition on cell growth (MOLM-13 and MV4;11 cells). In particular, the selected compound 12a exhibited the ability to regress tumors in mouse xenograft models using MOLM-13 and MV4;11 cells.     

Novel 4-(2-pyrimidinylamino)benzamide derivatives as potent hedgehog signaling pathway inhibitors

A series of novel hedgehog signaling pathway inhibitors have been designed and synthesized based on our previously reported scaffold of 4-(2-pyrimidinylamino)benzamide. The Hh signaling pathway inhibitory activities were evaluated by Gli-luciferase reporter method and most compounds showed more potent inhibitory activities than vismodegib. Three compounds were picked out to evaluated in vivo for their PK properties, and compound 23b bearing a 2-pyridyl A-ring and (morpholin-4-yl)methylene at 3-position of D-ring demonstrated satisfactory PK properties. This study suggested the 4-(2-pyrimidinylamino)benzamides were a series of potent Hh signaling pathway inhibitors, deserving to further structural optimization.     

Trisubstituted ureas as potent and selective mPGES-1 inhibitors

A novel series of trisubstituted ureas has been identified as potent and selective mPGES-1 inhibitors. These compounds are selective over other prostanoid enzymes such as PGF synthase and TX synthase. This series of inhibitors was developed by lead optimization of a hit from an internal HTS campaign. Lead compound 42 is potent in A549 cell assay (IC₅₀ of 0.34 μM) and in human whole blood assay (IC₅₀ of 2.1 μM). An efficient and versatile one-pot strategy for the formation of ureas, involving a reductive amination, was developed to generate these inhibitors.     

A novel Pd-catalyzed cyclization reaction of ureas for the synthesis of dihydroquinazolinone p38 kinase inhibitors

A series of potent p38 inhibitors based on the dihydroquinazoline scaffold was synthesized using a novel Pd-catalyzed cyclization reaction of aryl-benzyl ureas. Optimization of this compound class led to compound 20, which inhibits p38alpha in vitro with IC(50)=14 nM and is active in the mouse TNFalpha-release model.     

Structure-activity studies of a novel series of 5,6-fused heteroaromatic ureas as TRPV1 antagonists

Novel 5,6-fused heteroaromatic ureas were synthesized and evaluated for their activity as TRPV1 antagonists. It was found that 4-aminoindoles and indazoles are the preferential cores for the attachment of ureas. Bulky electron-withdrawing groups in the para-position of the aromatic ring of the urea substituents imparted the best in vitro potency at TRPV1. The most potent derivatives were assessed in in vivo inflammatory and neuropathic pain models. Compound 46, containing the indazole core and a 3,4-dichlorophenyl group appended to it via a urea linker, demonstrated in vivo analgesic activity upon oral administration. This derivative also showed selectivity versus other receptors in the CEREP screen and exhibited acceptable cardiovascular safety at levels exceeding the therapeutic dose.     

Design,synthesis, and biological evaluation of a series of piperazine ureas as fatty acid amide hydrolase inhibitors

A series of piperazine ureas were designed, synthesized, and evaluated for their potential as novel orally efficacious fatty acid amide hydrolase (FAAH) inhibitors for the treatment of neuropathic and inflammatory pain. We carried out an optimization study of compound 5 to improve its in vitro FAAH inhibitory activity, and identified the 2-pyrimidinylpiperazine derivative 21d with potent inhibitory activity, favorable DMPK profile and brain permeability. Compound 21d showed robust and dose-dependent analgesic efficacy in animal models of both neuropathic and inflammatory pain.     

Identification of amides derived from 1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid as potent inhibitors of human nicotinamide phosphoribosyltransferase (NAMPT)

Potent, 1H-pyrazolo[3,4-b]pyridine-containing inhibitors of the human nicotinamide phosphoribosyltransferase (NAMPT) enzyme were identified using structure-based design techniques. Many of these compounds exhibited nanomolar antiproliferation activities against human tumor lines in in vitro cell culture experiments, and a representative example (compound 26) demonstrated encouraging in vivo efficacy in a mouse xenograft tumor model derived from the A2780 cell line. This molecule also exhibited reduced rat retinal exposures relative to a previously studied imidazo-pyridine-containing NAMPT inhibitor. Somewhat surprisingly, compound 26 was only weakly active in vitro against mouse and monkey tumor cell lines even though it was a potent inhibitor of NAMPT enzymes derived from these species. The compound also exhibited only minimal effects on in vivo NAD levels in mice, and these changes were considerably less profound than those produced by an imidazo-pyridine-containing NAMPT inhibitor. The crystal structures of compound 26 and the corresponding PRPP-derived ribose adduct in complex with NAMPT were also obtained.     

Synthesis and biological evaluation of gem-diamine 1-N-iminosugars related to L-iduronic acid as inhibitors of heparan sulfate 2-O-sulfotransferase

A variety of gem-diamine 1-N-iminosugars related to L-iduronic acid were synthesized and evaluated as inhibitors of heparan sulfate uronyl 2-O-sulfotransferase using an in vitro enzyme assay. Two iminosugars containing guanidino groups acted as potent in vitro inhibitors of the enzyme.     

Analysis of mutagenic activity and ability to induce replication of polyoma DNA sequences by different model metabolites of the carcinogenic tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone.

The tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) requires metabolic activation to express its carcinogenic activity. This activation leads to the formation of methylating and pyridyloxobutylating agents. To determine the possible biological effects mediated by each of these metabolic pathways we have studied the activities of model compounds that are metabolized to either a methylating or pyridyloxobutylating species. Each model compound was evaluated for its mutagenic activity in both prokaryotic and eukaryotic cell systems. The model compounds were also tested for their ability to induce asynchronous replication of viral DNA sequences. We demonstrate here that both the methylating model compound acetoxymethylmethylnitrosamine (AMMN) and the pyridyloxobutylating model compound 4-(acetoxymethyl)-1-(3-pyridyl)-1-butanone (NNKOAc) were mutagenic in strains TA98, TA100, and TA1535 but not TA102. While NNKOAc appeared to be 10 times more potent than AMMN in Salmonella, AMMN was found to be a more potent mutagen in mammalian G12 cells. Both chemicals could induce asynchronous replication of polyoma DNA sequences in rat fibroblast cells carrying an integrated copy of the polyoma virus with AMMN appearing to be more active. Measurement of DNA adduct levels suggest that the damage produced by NNKOAc was at least as active as that produced by AMMN when viewed on a per adduct basis. The possible implications of the biological activities exhibited by methylating and pyridyloxobutylating model compounds to NNK induced carcinogenesis are discussed.     

Synthesis and pharmacological activities of xanthone derivatives as alpha-glucosidase inhibitors

Considerable interest has been attracted in xanthone and its derivatives because of their large variety of pharmacological activities. In this project, a series of hydroxylxanthones and their acetoxy and alkoxy derivatives were synthesized and evaluated as alpha-glucosidase inhibitors, aimed at clarifying the structure-activity correlation. The results indicated that these xanthone derivatives were capable of inhibiting in vitro alpha-glucosidase with moderate to good activities. Among them, polyhydroxylxanthones exhibited the highest activities and thus may be exploitable as a lead compound for the development of potent alpha-glucosidase inhibitors.     

Inhibition of mammalian aspartate transcarbamylase by quinazolinone derivatives

Quinazolinone derivatives have been studied as both in vitro and in vivo inhibitors of aspartate transcarbamylase (ATCase). In vitro treatment of mammalian ATCase with four compounds revealed that they inhibited enzyme activity and that 2-phenyl-1,3-4(H)benzothiazin-4-thione was the most potent one. This compound acts as a noncompetitive inhibitor towards both aspartate and carbamoyl phosphate. The values of the inhibition constant (K(i)) indicate that this compound exerts a potent inhibitory effect upon ATCase activity. Moreover, in vivo treatment with different doses of these derivatives showed also an inhibitory effect upon ATCase, the relative activity being decreased by 40%-58% with a 1 mg dose. These data support the inhibition of ATCase by quinazolinone derivatives as a new type of inhibitor for the enzyme.     

Design, synthesis and antitumor activities of novel bis-aryl ureas derivatives as Raf kinase inhibitors

A series of novel bis-aryl ureas containing trifluoromethyl imidazolyl group targeting Raf kinase were designed and synthesized based on the lead compound of Sorafenib. All the prepared compounds were evaluated for their in vitro antiproliferative activities against three human cancer cell lines including MDA-MB-231 (breast), BGC-823 (gastric), and SMMC-7721 (liver). Several compounds from the series exhibited excellent antitumor activities against all three tested cancer lines. Further their inhibitory activities against Raf kinase were investigated, and three compounds (11c, 11d, and 11p) demonstrated better activities than contrast drug Sorafenib. Especially compound 11c was found to be a potent and selective Raf kinase inhibitor and could be considered as a candidate compound for further development.     

Bromophenols as inhibitors of protein tyrosine phosphatase 1B with antidiabetic properties

A series of bromophenol derivatives were synthesized and evaluated as protein tyrosine phosphatase 1B (PTP1B) inhibitors in vitro and in vivo based on bromophenol 4e (IC(50)=2.42 μmol/L), which was isolated from red algae Rhodomela confervoides. The results showed that all of the synthesized compounds displayed weak to good PTP1B inhibition at tested concentration. Among them, highly brominated compound 4g exhibited promising inhibitory activity against PTP1B with IC(50) 0.68 μmol/L, which was approximately fourfold more potent than lead compound 4e. Further, compound 4g demonstrated high selectivity against other PTPs (TCPTP, LAR, SHP-1 and SHP-2). More importantly, in vivo antidiabetic activities investigations of compound 4g also demonstrated inspiring results.