Pier F. Cirillo

The non-diaryl heterocycle classes of p38 MAP kinase inhibitors.

The p38 mitogen activated protein (MAP) kinase is an integral enzyme involved in the production of a wide variety of pro-inflammatory cytokines from various cell types. The identification of this kinase and of the diaryl imidazole containing inhibitor, SB203580, initiated an intense discovery effort in this field. Numerous inhibitors were subsequently produced containing replacements for the imidazole, as well as some of the pharmacophores attached to it. During this time many other classes of potent p38 inhibitors emerged containing scaffolds and binding components not found in the diaryl imidazole group. This review summarizes nine of those classes. At least one of these classes requires the kinase to undergo reorganization prior to binding. From this diverse set of inhibitors four compounds have been reported advancing into human clinical trials.

A novel allosteric inhibitor of macrophage migration inhibitory factor (MIF)

Background: MIF is a pro-inflammatory cytokine implicated in autoimmune diseases. Results: A small molecule that binds to MIF and inhibits its cytokine activities was identified. Conclusion: The inhibitor binds in a unique region on MIF and reveals a new way to block the cytokine activities of MIF. Significance: The inhibitor is a valuable tool to design MIF-directed therapeutics for inflammatory diseases. Macrophage migration inhibitory factor (MIF) is a catalytic cytokine and an upstream mediator of the inflammatory pathway. MIF has broad regulatory properties, dysregulation of which has been implicated in the pathology of multiple immunological diseases. Inhibition of MIF activity with small molecules has proven beneficial in a number of disease models. Known small molecule MIF inhibitors typically bind in the tautomerase site of the MIF trimer, often covalently modifying the catalytic proline. Allosteric MIF inhibitors, particularly those that associate with the protein by noncovalent interactions, could reveal novel ways to block MIF activity for therapeutic benefit and serve as chemical probes to elucidate the structural basis for the diverse regulatory properties of MIF. In this study, we report the identification and functional characterization of a novel allosteric MIF inhibitor. Identified from a high throughput screening effort, this sulfonated azo compound termed p425 strongly inhibited the ability of MIF to tautomerize 4-hydroxyphenyl pyruvate. Furthermore, p425 blocked the interaction of MIF with its receptor, CD74, and interfered with the pro-inflammatory activities of the cytokine. Structural studies revealed a unique mode of binding for p425, with a single molecule of the inhibitor occupying the interface of two MIF trimers. The inhibitor binds MIF mainly on the protein surface through hydrophobic interactions that are stabilized by hydrogen bonding with four highly specific residues from three different monomers. The mode of p425 binding reveals a unique way to block the activity of the cytokine for potential therapeutic benefit in MIF-associated diseases.

An efficient procedure for the preparation of chiral β-substituted (E)-crotylsilanes: Application of a rhodium(II) catalyzed silylformylation of terminal alkynes

Abstract Functionalized β-substituted ( E )-crotylsilanes ( R )-7 and ( S )-8, bearing an alkyl or aryl group adjacent to the stereogenic C-Si center have been synthesized in an efficient four-step procedure initiated with a regio- and stereoselective silylformylation of a terminal alkyne catalyzed by dirhodium(II) perfluorobutyrate.

Inhibition of mycobacterial alanine racemase activity and growth by thiadiazolidinones

The genus Mycobacterium includes non-pathogenic species such as M. smegmatis, and pathogenic species such as M. tuberculosis, the causative agent of tuberculosis (TB). Treatment of TB requires a lengthy regimen of several antibiotics, whose effectiveness has been compromised by the emergence of resistant strains. New antibiotics that can shorten the treatment course and those that have not been compromised by bacterial resistance are needed. In this study, we report that thiadiazolidinones, a relatively little-studied heterocyclic class, inhibit the activity of mycobacterial alanine racemase, an essential enzyme that converts l-alanine to d-alanine for peptidoglycan synthesis. Twelve members of the thiadiazolidinone family were evaluated for inhibition of M. tuberculosis and M. smegmatis alanine racemase activity and bacterial growth. Thiadiazolidinones inhibited M. tuberculosis and M. smegmatis alanine racemases to different extents with 50% inhibitory concentrations (IC50) ranging from <0.03 to 28μM and 23 to >150μM, respectively. The compounds also inhibited the growth of these bacteria, including multidrug resistant strains of M. tuberculosis. The minimal inhibitory concentrations (MIC) for drug-susceptible M. tuberculosis and M. smegmatis ranged from 6.25μg/ml to 100μg/ml, and from 1.56 to 6.25μg/ml for drug-resistant M. tuberculosis. The in vitro activities of thiadiazolidinones suggest that this family of compounds might represent starting points for medicinal chemistry efforts aimed at developing novel antimycobacterial agents.

1,4-Diazepane compounds as potent and selective CB2 agonists: optimization of metabolic stability.

A high-throughput screening campaign has identified 1,4-diazepane compounds which are potent Cannabinoid receptor 2 agonists with excellent selectivity against the Cannabinoid receptor 1. This class of compounds suffered from low metabolic stability. Following various strategies, compounds with a good stability in liver microsomes and rat PK profile have been identified.

Double stereodifferentiation in the lewis acid promoted crotylation of (S)-2-Alkoxypropanal with chiral β-Alkyl (E)-Crotylsilanes

Abstract The sense and level of 1,2-asymmetric induction have been evaluated in the Lewis acid promoted addition of ( E )crotylsilanes ( S )-1 and ( R )-2 to ( S )-2-alkoxypropanal 3 and 7. These aldehydes are substituted at the α-position with benzyloxy (OBn) to reinforce chelation and tert-butyldiphenylsilyloxy (TBDPSO) groups to prevent chelation with bidentate Lewis acids. The nature of the Lewis acid and the chirality of the silane reagent were found to playa pivotal role in the direction and levels of carbonyl diastcreoface selectivity.

Palladium-catalyzed hydrogenolysis of acyldimethylphenylsilanes to aldehydes

Abstract Syn-α,β-dialkoxy-acyldimethylphenylsilanes of structural type 1 , bearing benzyl, benzyloxymethyl (BOM) ether protecting groups can be efficiently and selectively desilated to produce the corresponding aldehydes 2 by catalytic hydrogenolysis over 10% palladium on carbon in ethanol or ethyl acetate.

Selective CB2 receptor agonists. Part 1: The identification of novel ligands through computer-aided drug design (CADD) approaches

Computer-aided drug design scaffold hopping strategies were utilized to identify new classes of CB2 agonists when compounds of an established series with low nanomolar potency were challenging to optimize for good drug-like properties. Use of ligand-based design strategies through BI Builder (a tool for de novo design) and PharmShape (a virtual screening software package) approaches led to the discovery of new chemotypes. Specifically, compounds containing azetidine-, proline-, and piperidine-based cores were found to have low nanomolar and picomolar CB2 agonist activities with drug-like properties considered appropriate for early profiling.

Selective CB2 receptor agonists. Part 3: The optimization of a piperidine-based series that demonstrated efficacy in an in vivo neuropathic pain model

A novel class of potent cannabinoid receptor 2 (CB2) agonists based on a (S)-piperidine scaffold was identified using ligand-based pharmacophore models. Optimization of solubility and metabolic stability led to the identification of several potent CB2 agonists (e.g., 30) that displayed selectivity over cannabinoid receptor 1 (CB1) and acceptable drug like properties. In rats, compound 30 demonstrated a favorable pharmacokinetic profile and efficacy in a Streptozotocin-induced diabetic neuropathy model, with full reversal of mechanical hyperalgesia.