Potent, exceptionally selective, orally bioavailable inhibitors of TNF-alpha Converting Enzyme (TACE): novel 2-substituted-1H-benzo[d]imidazol-1-yl)methyl)benzamide P1' substituents

Novel ((2-substituted-1H-benzo[d]imidazol-1-yl)methyl)benzamides were found to be excellent P1' substituents in conjunction with unique constrained beta-amino hydroxamic acid scaffolds for the discovery of potent selective inhibitors of TNF-alpha Converting Enzyme (TACE). Optimized examples proved potent for TACE, exceptionally selective over a wide panel of MMP and ADAM proteases, potent in the suppression of LPS-induced TNF-alpha in human whole blood and orally bioavailable.     

Non-hydroxamate 5-phenylpyrimidine-2,4,6-trione derivatives as selective inhibitors of tumor necrosis factor-alpha converting enzyme

New inhibitors of tumor necrosis factor-alpha converting enzyme (TACE) were discovered with a pyrimidine-2,4,6-trione in place of the commonly used hydroxamic acid. These non-hydroxamate TACE inhibitors were developed by incorporating a 4-(2-methyl-4-quinolinylmethoxy)phenyl group, an optimized TACE selective P1' group. Several leads were identified with IC50 values around 100 nM in a porcine TACE assay and selective over MMP-1, -2, -9, -13, and aggrecanase.     

Gelastatins and their hydroxamates as dual functional inhibitors for TNF-alpha converting enzyme and matrix metalloproteinases: synthesis, biological evaluation, and mechanism studies

The hydroxamic acid analogues (2) of the natural product gelastatins (1) were prepared by 1 step conversion reaction. The synthetic analogues (2) showed potent enzymatic inhibitory activities against MMP-2, MMP-9, and TACE IC50's of 6, 23, and 28 nM, respectively. In addition, 2 were able to inhibit TNF-alpha production effectively in mice as well as in a macrophage cell line, RAW 264.7. The protective effect of 2 also was examined on LPS-induced acute septic shock model. The mechanism of TNF-alpha inhibition was examined by RT-PCR and Western blot analyses. The relation of TACE and alpha-secretase was examined using cellular alpha-secretase assays on IMR-32 and SH-SY5Y cell lines. The docking mode of 2 with the catalytic domain of TACE was illustrated to analyze the binding mode for the further analogue design.     

Synthesis and structure-activity relationship of a novel sulfone series of TNF-alpha converting enzyme inhibitors

Replacement of the amide functionality in IM491 (N-hydroxy-(5S,6S)-1-methyl-6-[[4-(2-methyl-4-quinolinylmethoxy)anilinyl]carbonyl]5-piperidinecarboxamide) with a sulfonyl group led to a new series of alpha,beta-cyclic and beta,beta-cyclic gamma-sulfonyl hydroxamic acids, which were potent TNF-alpha converting enzyme (TACE) inhibitors. Among them, inhibitor 4b (N-hydroxy-(4S,5S)-1-methyl-5-[[4-(2-methyl-4-quinolinylmethoxy)phenyl]sulfonylmethyl]-4-pyrrolidinecarboxamide) exhibited IC50 values of < 1 nM and 180 nM in porcine TACE (pTACE) and cell assays, respectively, with excellent selectivity over MMP-1, -2, -9 and -13 and was orally bioavailable with an F value of 46% in mice.     

Synthesis and biological activity of selective pipecolic acid-based TNF-alpha converting enzyme (TACE) inhibitors

A series of novel, selective TNF-alpha converting enzyme inhibitors based on 4-hydroxy and 5-hydroxy pipecolate hydroxamic acid scaffolds is described. The potency and selectivity of TACE inhibition is dramatically influenced by the nature of the sulfonamide group which interacts with the S1' site of the enzyme. Substituted 4-benzyloxybenzenesulfonamides exhibit excellent TACE potency with >100x selectivity over inhibition of matrix metalloprotease-1 (MMP-1). Alkyl substituents on the ortho position of the benzyl ether moiety give the most potent inhibition of TNF-alpha release in LPS-treated human whole blood.     

Synthesis and biological activity of selective azasugar-based TACE inhibitors

A series of azasugar-based hydroxamic acid derivatives bearing 2R,3R,4R,5R-configuration is described. Compound 4c with 4,5-O-acetonide group showed excellent in vitro potency against TACE, with high selectivity over MMP-1 and moderate selectivity over MMP-3 and MMP-9.     

Synthesis and structure-activity relationship of a novel, achiral series of TNF-alpha converting enzyme inhibitors

A novel series of achiral TNF-alpha converting enzyme (TACE) inhibitors has been discovered. These compounds exhibited activities from 0.35 to 11nM in a porcine TACE assay and inhibited TNF-alpha production in an LPS-stimulated whole blood assay with an IC(50) value of 23nM for the most potent one. They also have excellent selectivities over related metalloproteases including aggrecanases.     

Rational design of a novel, potent, and orally bioavailable cyclohexylamine DPP-4 inhibitor by application of molecular modeling and X-ray crystallography of sitagliptin

Molecular modeling was used to design a rigid analog of sitagliptin 1. The X-ray crystal structure of sitagliptin bound to DPP-4 suggested that the central beta-amino butyl amide moiety could be replaced with a cyclohexylamine group. This was confirmed by structural analysis and the resulting analog 2a was synthesized and found to be a potent DPP-4 inhibitor (IC(50)=21 nM) with excellent in vivo activity and pharmacokinetic profile.     

Discovery of novel hydroxamates as highly potent tumor necrosis factor-alpha converting enzyme inhibitors. Part II: optimization of the S3' pocket

A series of cyclopropyl hydroxamic acids were prepared. Many of the compounds displayed picomolar affinity for the TACE enzyme while maintaining good to excellent selectivity profiles versus MMP-1, -2, -3, -7, -14, and ADAM-10. X-ray analysis of an inhibitor in the TACE active site indicated that the molecules bound to the enzyme in the S1'-S3' pocket.     

Synthesis and structure-activity relationship of a novel, non-hydroxamate series of TNF-alpha converting enzyme inhibitors

A novel series of TNF-alpha converting enzyme (TACE) inhibitors which are non-hydroxamate have been discovered. These compounds use a triazolethione moiety as the zinc binding ligand and exhibit IC50 values from 1.5 to 100 nM in a porcine TACE assay. They also have excellent selectivities over other MMPs.     

Synthesis and SAR of bicyclic heteroaryl hydroxamic acid MMP and TACE inhibitors

Potent and selective bicyclic heteroaryl hydroxamic acid MMP and TACE inhibitors were synthesized by a novel convergent route. Selectivity and efficacy versus MMPs and TACE could be controlled by appropriate substitution on the scaffolds and by variation of the P1' group. Select compounds were found to be effective in in vivo models of arthritis.     

Alpha,beta-cyclic-beta-benzamido hydroxamic acids: novel templates for the design, synthesis, and evaluation of selective inhibitors of TNF-alpha converting enzyme (TACE)

Selective inhibitors of TNF-alpha Converting Enzyme (TACE) based on (1R,2S)-cyclopentyl, (3S,4S)-pyrrolidinyl, and (3R,4S)-tetrahydrofuranyl beta-benzamido hydroxamic acids have been synthesized and evaluated. This study has led to the discovery of novel inhibitors whose profiles include activity against TACE in an enzyme assay, potency in the suppression of LPS-stimulated TNF-alpha in human whole blood, selectivity against a panel of MMPs and oral bioavailability.     

Synthesis and biological evaluation of hydroxamate-Based inhibitors of glutamate carboxypeptidase II

A series of hydroxamic acids has been prepared as potential inhibitors of glutamate carboxypeptidase II (GCP II). Compounds based on a P1' residue (primed-side inhibitors) were more potent than those based on a P1 group (unprimed-side inhibitors). Inhibitory potency of the primed-side GCP II inhibitors was found to be dependent on the number of methylene units between the hydroxamate group and pentanedioic acid. Succinyl hydroxamic acid derivative, 2-(hydroxycarbamoylmethyl)pentanedioic acid, is the most potent GCP II inhibitor with an IC(50) value of 220nM. The comparison of the results to those of other classes of GCP II inhibitors as well as hydroxamate-based MMP inhibitors provides further insight into the structure-activity relationships of GCP II inhibition.     

Rational design, synthesis and structure-activity relationships of a cyclic succinate series of TNF-alpha converting enzyme inhibitors. Part 2: lead optimization

Modifications of the lead TACE inhibitor 1 (N-hydroxy-trans-2-[[4-(4-quinolinyloxymethyl)anilinyl]carbonyl]-1-cyclohexanecarboxamide) at the cyclohexyl ring and the quinoline moiety led to the identification of a series of piperidine containing TACE inhibitors with potent activity in the inhibition of TNF-alpha release in the whole blood assay (WBA). The most potent analogue IM491 [N-hydroxy-(5S,6S)-1-methyl-6-[[4-(2-methyl-4-quinolinylmethoxy)anilinyl]carbonyl]-5-piperidinecarboxamide] exhibited an IC(50) value of 20 nM in WBA with excellent selectivity over MMP-1, -2 and -9 and is orally bioavailable with an F value of 43% in beagle dogs.     

Discovery of novel hydantoins as selective non-hydroxamate inhibitors of tumor necrosis factor-alpha converting enzyme (TACE)

A series of novel hydantoins was designed and synthesized as structural alternatives to hydroxamate inhibitors of TACE. 5-Mono- and di-substituted hydantoins exhibited activity with IC50 values of 11-60 nM against porcine TACE in vitro and excellent selectivity against other MMPs.     

Discovery of dihydroquinoxalinone acetamides containing bicyclic amines as potent Bradykinin B1 receptor antagonists

Replacement of the core beta-amino acid in our previously reported piperidine acetic acid and beta-phenylalanine-based Bradykinin B1 antagonists by dihydroquinoxalinone acetic acid increases the in vitro potency and metabolic stability. The most potent compounds from this series have IC(50)s<0.2 nM in a human B1 receptor functional assay. A molecular modeling study of the binding modes of key compounds, based on a B1 homology model, explains the structure-activity relationship (SAR) for these analogs.     

Rational design, synthesis and structure-activity relationships of a cyclic succinate series of TNF-alpha converting enzyme inhibitors. Part 1: lead identification

Rational design based on the broad spectrum MMP inhibitor CGS 27023A led to the identification of a novel series of cyclic succinate TACE inhibitors. As a mixture of two enantiomers, the lead compound 17b exhibited potent enzyme activity (IC(50)=8 nM) in the inhibition of porcine TNF-alpha converting enzyme (pTACE) and excellent selectivity over aggrecanase and MMP-1, -2 and -9.     

Inhibition of lipid A biosynthesis as the primary mechanism of CHIR-090 antibiotic activity in Escherichia coli

The deacetylation of UDP-3-O-[(R)-3-hydroxymyristoyl]-N-acetylglucosamine (UDP-3-O-acyl-GlcNAc) by LpxC is the committed reaction of lipid A biosynthesis. CHIR-090, a novel N-aroyl-l-threonine hydroxamic acid, is a potent, slow, tight-binding inhibitor of the LpxC deacetylase from the hyperthermophile Aquifex aeolicus, and it has excellent antibiotic activity against Pseudomonas aeruginosa and Escherichia coli, as judged by disk diffusion assays. We now report that CHIR-090 is also a two-step slow, tight-binding inhibitor of E. coli LpxC with Ki = 4.0 nM, Ki* = 0.5 nM, k5 = 1.9 min-1, and k6 = 0.18 min-1. CHIR-090 at low nanomolar levels inhibits LpxC orthologues from diverse Gram-negative pathogens, including P. aeruginosa, Neisseria meningitidis, and Helicobacter pylori. In contrast, CHIR-090 is a relatively weak competitive and conventional inhibitor (lacking slow, tight-binding kinetics) of LpxC from Rhizobium leguminosarum (Ki = 340 nM), a Gram-negative plant endosymbiont that is resistant to this compound. The KM (4.8 microM) and the kcat (1.7 s-1) of R. leguminosarum LpxC with UDP-3-O-[(R)-3-hydroxymyristoyl]-N-acetylglucosamine as the substrate are similar to values reported for E. coli LpxC. R. leguminosarum LpxC therefore provides a useful control for validating LpxC as the primary target of CHIR-090 in vivo. An E. coli construct in which the chromosomal lpxC gene is replaced by R. leguminosarum lpxC is resistant to CHIR-090 up to 100 microg/mL, or 400 times above the minimal inhibitory concentration for wild-type E. coli. Given its relatively broad spectrum and potency against diverse Gram-negative pathogens, CHIR-090 is an excellent lead for the further development of new antibiotics targeting the lipid A pathway.     

Discovery of 3,3-dimethyl-5-hydroxypipecolic hydroxamate-based inhibitors of aggrecanase and MMP-13

A series of pipecolic hydroxamate inhibitors of MMP-13 and aggrecanase was discovered based on screening known inhibitors of TNF-alpha converting enzyme (TACE). Potency versus aggrecanase was optimized by modification of the benzyloxyarylsulfonamide group. Incorporation of geminal alkyl substitution at the 3-position of the piperidine ring improved metabolic stability, presumably by increasing steric hindrance around the metabolically labile hydroxamic acid. This modification also resulted in dramatic improvement of aggrecanase activity with a slight reduction in selectivity versus MMP-1. Synthesis, structure activity relationships, and strategies to reduce metabolic clearance are described.