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A series of 8-hydroxy quinolines were identified as potent inhibitors of catechol O-methyltransferase (COMT) with selectivity for the membrane-bound form of the enzyme. Small substituents at the 7-position of the quinoline were found to increase metabolic stability without sacrificing potency. Compounds with good pharmacokinetics and brain penetration were identified and demonstrated in vivo modulation of dopamine metabolites in the brain. An X-ray co-crystal structure of compound 21 in the S-COMT active site shows chelation of the active site magnesium similar to catechol-based inhibitors. These compounds should prove useful for treatment of many neurological and psychiatric conditions associated with compromised cortical dopamine signaling.

A series of bicyclic pyridones were identified as potent inhibitors of catechol O-methyltransferase (COMT). Substituted benzyl groups attached to the basic nitrogen of the core scaffold gave the most potent inhibitors within this series. Rat pharmacokinetic studies showed medium to high levels of clearance for this series, but with high free fraction due to remarkably low levels of protein and tissue binding. In rat biomarker studies, levels of unbound drug exposure are seen in the brain, which exceed their respective IC50s, leading to changes in the levels of dopamine metabolites in a manner consistent with COMT inhibition.

Aims Kv1.1 (KCNA1) channels contribute to the control of neuronal excitability and have been associated with epilepsy. Kv1.1 channels can associate with the cytoplasmic Kvβ1 subunit resulting in rapid inactivating A-type currents. We hypothesized that removal of channel inactivation, by modulating Kv1.1/Kvβ1 interaction with a small molecule, would lead to decreased neuronal excitability and anticonvulsant activity. Methods We applied high-throughput screening to identify ligands able to modulate the Kv1.1-T1 domain/Kvβ1 protein complex. We then selected a compound that was characterized on recombinant Kv1.1/Kvβ1 channels by electrophysiology and further evaluated on sustained neuronal firing and on in vitro epileptiform activity using a high K+ -low Ca2+ model in hippocampal slices. Results We identified a novel compound able to modulate the interaction of the Kv1.1/Kvβ1 complex and that produced a functional inhibition of Kv1.1/Kvβ1 channel inactivation. We demonstrated that this compound reduced the sustained repetitive firing in hippocampal neurons and was able to abolish the development of in vitro epileptiform activity. Conclusions This study describes a rational drug discovery approach for the identification of novel ligands that inhibit Kv1.1 channel inactivation and provides pharmacological evidence that such a mechanism translates into physiological effects by reducing in vitro epileptiform activity.

Apoptosis signal-regulating kinase 1 (ASK1) is an evolutionarily conserved mitogen-activated protein kinase (MAPK) kinase kinase which plays important roles in stress and immune responses. Here, we show that ASK1 deficiency attenuates neuroinflammation in experimental autoimmune encephalomyelitis (EAE), without affecting the proliferation capability of T cells. Moreover, we found that EAE upregulates expression of Toll-like receptors (TLRs) in activated astrocytes and microglia, and that TLRs can synergize with ASK1-p38 MAPK signalling in the release of key chemokines from astrocytes. Consequently, oral treatment with a specific small molecular weight inhibitor of ASK1 suppressed EAE-induced autoimmune inflammation in both spinal cords and optic nerves. These results suggest that the TLR-ASK1-p38 pathway in glial cells may serve as a valid therapeutic target for autoimmune demyelinating disorders including multiple sclerosis.

The discovery of a novel series of S1P1 agonists is described. Starting from a micromolar HTS positive, iterative optimization gave rise to several single-digit nanomolar S1P1 agonists. The compounds were able to induce internalization of the S1P1 receptor, and a selected compound was shown to be able to induce lymphopenia in mice after oral dosing.

SummaryTyrosine kinases and phosphatases establish the crucial balance of tyrosine phosphorylation in cellular signaling, but creating specific inhibitors of protein Tyr phosphatases (PTPs) remains a challenge. Here, we report the development of a potent, selective inhibitor of Mycobacterium tuberculosis PtpB, a bacterial PTP that is secreted into host cells where it disrupts unidentified signaling pathways. The inhibitor, (oxalylamino-methylene)-thiophene sulfonamide (OMTS), showed an IC50 of 440 ± 50 nM and >60-fold specificity for PtpB over six human PTPs. The 2 Å resolution crystal structure of PtpB in complex with OMTS revealed a large rearrangement of the enzyme, with some residues shifting >27 Å relative to the PtpB:PO4 complex. Extensive contacts with the catalytic loop provide a potential basis for inhibitor selectivity. Two OMTS molecules bound adjacent to each other, raising the possibility of a second substrate phosphotyrosine binding site in PtpB. The PtpB:OMTS structure provides an unanticipated framework to guide inhibitor improvement.

Protein tyrosine phosphatases (PTPs) have emerged as a new and promising class of signaling targets, since the discovery of PTP1B as a major drug target for diabetes and obesity. Blocking individual PTPs results in the activation of specific tyrosine phosphorylation events, but matching PTPs with such pathways and therapeutic indications is a complex undertaking. The history of PTP1B shows that its unusual knockout phenotype and observations with generic and antisense inhibitors in vivo, but not its classical molecular biology, triggered the rapid development of inhibitors that are today being developed for the clinic.

Contact hypersensitivity (CHS) is a form of delayed-type hypersensitivity triggered by the response to reactive haptens (sensitization) and subsequent challenge (elicitation). Here, we show that ASK1 promotes CHS and that suppression of ASK1 during the elicitation phase is sufficient to attenuate CHS. ASK1 knockout (KO) mice exhibited impaired 2,4-dinitrofluorobenzene (DNFB)-induced CHS. The suppression of ASK1 activity during the elicitation phase through a chemical genetic approach or a specific inhibitory compound significantly reduced the CHS response to a level similar to that observed in ASK1 KO mice. The reduced response was concomitant with the strong inhibition of production of IL-17, a cytokine that plays an important role in CHS and other inflammatory diseases, from sensitized lymph node cells. These results suggest that ASK1 is relevant to the overall CHS response during the elicitation phase and that ASK1 may be a promising therapeutic target for allergic contact dermatitis and other IL-17-related inflammatory diseases., Scientific Reports, 4, 4714; 2014

A short route to peptide C-terminal thioesters was developed that does not require the use of special linkers or resins and is compatible with standard Fmoc chemistry. Following conventional solid-phase peptide synthesis, an excess of Me(2)AlCl and EtSH in dichloromethane cleaves peptides from Wang or Pam resins to give the corresponding thioesters directly in good yield and purity.

Reaction of sulfur ylides with suitably 4-functionalized-5,5-dimethyl-2-cyclopentenones allows an efficient entry to the bicyclo[3.1.0]hexan-2-one skeleton which proved to be a valuable precursor of vinyl cyclopropane carboxylic acids. Application to the synthesis of (d,l)- and (d)-(cis)-chrysanthemic acid is described.

Enedione 1 and related rac- and optically active enones 2 bearing a hydroxyl- 2a or a protected- 2b-c or an activated- 2d 4-hydroxyl group at C-4 have been efficiently synthesized from cheap and readily available starting materials.

Bicyclo[3.1.0]hexanones bearing an aryl group on the cyclopropane ring are stereoselectively prepared on reaction of the corresponding benzylidene sulfuranes with cyclopentenones. The synthesis of compounds bearing geminal phenyl and methyl groups on the cyclopropane ring proves to be possible because the corresponding sulfonium salt, inaccessible until now, is now available.

Reaction of sulfur ylides with suitably 4-functionalized-5,5-dimethyl-2-cyclopentenones allows an efficient entry to the bicyclo[3.1.0]hexan-2-one skeleton which proved to be a valuable precursor of vinyl cyclopropane carboxylic acids. Application to the synthesis of (d,l)- and (d)-(cis)-chrysanthemic acid is described.

Enedione 1 and related rac- and optically active enones 2 bearing a hydroxyl- 2a or a protected- 2b-c or an activated- 2d 4-hydroxyl group at C-4 have been efficiently synthesized from cheap and readily available starting materials.

Bicyclo[3.1.0]hexanones bearing an aryl group on the cyclopropane ring are stereoselectively prepared on reaction of the corresponding benzylidene sulfuranes with cyclopentenones. The synthesis of compounds bearing geminal phenyl and methyl groups on the cyclopropane ring proves to be possible because the corresponding sulfonium salt, inaccessible until now, is now available.

A simple protocol for the synthesis of 3-amino-[1,2,4]triazolo[4,3-a]pyridines is reported. The newly developed one-pot methodology involves the reaction of hydrazinopyridine with isothiocyanates to give the corresponding thiosemicarbazides, which are further desulfurized in situ using polymer-supported Mukaiyama’s reagent to promote the final cyclization and formation of the central core. Aryl isothiocyanates bearing both electron-donating and electron-withdrawing groups are well tolerated, and the expected compounds were obtained in excellent purities and yields after removal of salts with a SPE-NH2 column. This methodology proved to be robust in the extension to 3-amino-[1,2,4]triazolo[4,3-a]-pyrazines and 3-amino-[1,2,4]triazolo[4,3-c]-pyrimidines, and no significant differences were noticed in terms of purities and yields. The straightforward protocol developed, mix, filter, and evaporate, is appropriate for performing multiple reactions in parallel fashion without need of purification.

A simple protocol for the synthesis of 3-amino-[1,2,4]triazolo[4,3-a]pyridines is reported. The newly developed one-pot methodology involves the reaction of hydrazinopyridine with isothiocyanates to give the corresponding thiosemicarbazides, which are further desulfurized in situ using polymer-supported Mukaiyama’s reagent to promote the final cyclization and formation of the central core. Aryl isothiocyanates bearing both electron-donating and electron-withdrawing groups are well tolerated, and the expected compounds were obtained in excellent purities and yields after removal of salts with a SPE-NH2 column. This methodology proved to be robust in the extension to 3-amino-[1,2,4]triazolo[4,3-a]-pyrazines and 3-amino-[1,2,4]triazolo[4,3-c]-pyrimidines, and no significant differences were noticed in terms of purities and yields. The straightforward protocol developed, mix, filter, and evaporate, is appropriate for performing multiple reactions in parallel fashion without need of purification.

We describe novel, cell-permeable, and bioavailable salicylic acid derivatives that are potent and selective inhibitors of GLEPP1/protein-tyrosine phosphatase φ. Two previously described GLEPP1 substrates, paxillin and Syk, are both required for cytoskeletal rearrangement and cellular motility of leukocytes in chemotaxis. We show here that GLEPP1 inhibitors prevent dephosphorylation of Syk1 and paxillin in resting cells and block primary human monocyte and mouse bone marrow-derived macrophage chemotaxis in a gradient of monocyte chemotactic protein-1. In mice, the GLEPP1 inhibitors also reduce thioglycolate-induced peritoneal chemotaxis of neutrophils, lymphocytes, and macrophages. In murine disease models, the GLEPP1 inhibitors significantly reduce severity of contact hypersensitivity, a model for allergic dermatitis, and dextran sulfate sodium-induced ulcerative colitis, a model for inflammatory bowel disease. Taken together, our data provide confirmation that GLEPP1 plays an important role in controlling chemotaxis of multiple types of leukocytes and that pharmacological inhibition of this phosphatase may have therapeutic use.

A practical protocol for the parallel synthesis of 2-oxazolines using polymer-supported reagents is described. Polymer-supported Mukaiyama reagent is used to couple a carboxylic acid with an amino alcohol, giving a beta-hydroxyamide, which is then cyclized in situ using either polymer-supported sulfonyl chloride resin or polymer-bound 2-fluoropyridinium triflate. Both 2,4-disubstituted and 2,4,5-trisubstituted 2-oxazolines are obtained in high yields and excellent purities after a simple resin filtration and solvent evaporation routine.

Polymer-supported N-alkyl-2-chloro pyridinium triflate was synthesized in one step from Wang resin. This reagent proved to be a very effective coupling reagent for the synthesis of esters or amides from carboxylic acids and alcohols or amines (primary and secondary). [reaction: see text]

Only very limited methods are available for the synthesis of 5-amino imidazoles. We report in this paper that three-component reaction of acyl chlorides, carbodiimides and α-isocyanoacetates or TosMIC took place smoothly in the presence of Et3N (2.5 equiv.) and a catalytic amount of copper iodide (0.2 equiv.) to afford 1,4-disubstituted 5-acetamidoimidazoles in good yields.