RESUMEN
Glycogen synthase kinase-3 (GSK-3) regulates multiple cellular processes in diabetes, oncology, and neurology. N-(3-(1H-1,2,4-triazol-1-yl)propyl)-5-(3-chloro-4-methoxyphenyl)oxazole-4-carboxamide (PF-04802367 or PF-367) has been identified as a highly potent inhibitor, which is among the most selective antagonists of GSK-3 to date. Its efficacy was demonstrated in modulation of tau phosphorylation inâ vitro and inâ vivo. Whereas the kinetics of PF-367 binding in brain tissues are too fast for an effective therapeutic agent, the pharmacokinetic profile of PF-367 is ideal for discovery of radiopharmaceuticals for GSK-3 in the central nervous system. A (11) C-isotopologue of PF-367 was synthesized and preliminary PET imaging studies in non-human primates confirmed that we have overcome the two major obstacles for imaging GSK-3, namely, reasonable brain permeability and displaceable binding.
Asunto(s)
Encéfalo/efectos de los fármacos , Encéfalo/diagnóstico por imagen , Neuroimagen , Oxazoles/farmacología , Tomografía de Emisión de Positrones , Inhibidores de Proteínas Quinasas/farmacología , Triazoles/farmacología , Proteínas tau/antagonistas & inhibidores , Encéfalo/metabolismo , Cristalografía por Rayos X , Relación Dosis-Respuesta a Droga , Glucógeno Sintasa Quinasa 3/antagonistas & inhibidores , Glucógeno Sintasa Quinasa 3/metabolismo , Humanos , Modelos Moleculares , Estructura Molecular , Oxazoles/síntesis química , Oxazoles/química , Fosforilación/efectos de los fármacos , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/química , Triazoles/síntesis química , Triazoles/química , Proteínas tau/metabolismoRESUMEN
Peptidoglycan synthesis is an underutilized drug target in Mycobacterium tuberculosis (Mtb). Diazabicyclooctanes (DBOs) are a class of broad-spectrum ß-lactamase inhibitors that also inhibit certain peptidoglycan transpeptidases that are important in mycobacterial cell wall synthesis. We evaluated the DBO durlobactam as an inhibitor of BlaC, the Mtb ß-lactamase, and multiple Mtb peptidoglycan transpeptidases (PonA1, LdtMt1, LdtMt2, LdtMt3, and LdtMt5). Timed electrospray ionization mass spectrometry (ESI-MS) captured acyl-enzyme complexes with BlaC and all transpeptidases except LdtMt5. Inhibition kinetics demonstrated durlobactam was a potent and efficient DBO inhibitor of BlaC (KI app 9.2 ± 0.9 µM, k2/K 5600 ± 560 M-1 s-1) and similar to clavulanate (KI app 3.3 ± 0.6 µM, k2/K 8400 ± 840 M-1 s-1); however, durlobactam had a lower turnover number (tn = kcat/kinact) than clavulanate (1 and 8, respectively). KI app values with durlobactam and clavulanate were similar for peptidoglycan transpeptidases, but ESI-MS captured durlobactam complexes at more time points. Molecular docking and simulation demonstrated several productive interactions of durlobactam in the active sites of BlaC, PonA1, and LdtMt2. Antibiotic susceptibility testing was conducted on 11 Mtb isolates with amoxicillin, ceftriaxone, meropenem, imipenem, clavulanate, and durlobactam. Durlobactam had a minimum inhibitory concentration (MIC) range of 0.5-16 µg/mL, similar to the ranges for meropenem (1-32 µg/mL) and imipenem (0.5-64 µg/mL). In ß-lactam + durlobactam combinations (1:1 mass/volume), MICs were lowered 4- to 64-fold for all isolates except one with meropenem-durlobactam. This work supports further exploration of novel ß-lactamase inhibitors that target BlaC and Mtb peptidoglycan transpeptidases.
Asunto(s)
Aminoaciltransferasas , Antituberculosos , Mycobacterium tuberculosis , Inhibidores de beta-Lactamasas , beta-Lactamasas , Aminoaciltransferasas/antagonistas & inhibidores , Antituberculosos/farmacología , Antituberculosos/química , Compuestos de Azabiciclo/farmacología , Compuestos de Azabiciclo/química , Proteínas Bacterianas/antagonistas & inhibidores , Proteínas Bacterianas/química , Inhibidores de beta-Lactamasas/farmacología , Inhibidores de beta-Lactamasas/química , beta-Lactamasas/metabolismo , beta-Lactamasas/química , Cinética , Pruebas de Sensibilidad Microbiana , Simulación del Acoplamiento Molecular , Mycobacterium tuberculosis/efectos de los fármacos , Mycobacterium tuberculosis/enzimologíaRESUMEN
We identified potent, selective PDE2 inhibitors by optimizing residual PDE2 activity in a series of PDE4 inhibitors, while simultaneously minimizing PDE4 activity. These newly designed PDE2 inhibitors bind to the PDE2 enzyme in a cGMP-like mode in contrast to the cAMP-like binding mode found in PDE4. Structure activity relationship studies coupled with an inhibitor bound crystal structure in the active site of the catalytic domain of PDE2 identified structural features required to minimize PDE4 inhibition while simultaneously maximizing PDE2 inhibition.
Asunto(s)
Azirinas/química , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 2/antagonistas & inhibidores , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 4/química , Dihidropiridinas/química , Inhibidores de Fosfodiesterasa 4/química , Inhibidores de Fosfodiesterasa/química , Animales , Azirinas/metabolismo , Azirinas/uso terapéutico , Sitios de Unión , Dominio Catalítico , Cristalografía por Rayos X , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 2/metabolismo , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 4/metabolismo , Dihidropiridinas/metabolismo , Dihidropiridinas/uso terapéutico , Modelos Animales de Enfermedad , Evaluación Preclínica de Medicamentos , Osteoartritis/tratamiento farmacológico , Inhibidores de Fosfodiesterasa/metabolismo , Inhibidores de Fosfodiesterasa/uso terapéutico , Unión Proteica , Relación Estructura-ActividadRESUMEN
Selective phosphodiesterase 2 (PDE2) inhibitors are shown to have efficacy in a rat model of osteoarthritis (OA) pain. We identified potent, selective PDE2 inhibitors by optimizing residual PDE2 activity in a series of phosphodiesterase 4 (PDE4) inhibitors, while minimizing PDE4 inhibitory activity. These newly designed PDE2 inhibitors bind to the PDE2 enzyme in a cGMP-like binding mode orthogonal to the cAMP-like binding mode found in PDE4. Extensive structure activity relationship studies ultimately led to identification of pyrazolodiazepinone, 22, which was >1000-fold selective for PDE2 over recombinant, full length PDEs 1B, 3A, 3B, 4A, 4B, 4C, 7A, 7B, 8A, 8B, 9, 10 and 11. Compound 22 also retained excellent PDE2 selectivity (241-fold to 419-fold) over the remaining recombinant, full length PDEs, 1A, 4D, 5, and 6. Compound 22 exhibited good pharmacokinetic properties and excellent oral bioavailability (F=78%, rat). In an in vivo rat model of OA pain, compound 22 had significant analgesic activity 1 and 3h after a single, 10 mg/kg, subcutaneous dose.
Asunto(s)
Azepinas/química , Azirinas/química , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 2/antagonistas & inhibidores , Dihidropiridinas/química , Inhibidores de Fosfodiesterasa/química , Pirazoles/química , Analgésicos/química , Analgésicos/farmacocinética , Analgésicos/uso terapéutico , Animales , Azepinas/farmacocinética , Azepinas/uso terapéutico , Azirinas/farmacocinética , Azirinas/uso terapéutico , Sitios de Unión , Dominio Catalítico , Cristalografía por Rayos X , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 2/metabolismo , Dihidropiridinas/farmacocinética , Dihidropiridinas/uso terapéutico , Modelos Animales de Enfermedad , Evaluación Preclínica de Medicamentos , Semivida , Osteoartritis/tratamiento farmacológico , Inhibidores de Fosfodiesterasa 4/química , Inhibidores de Fosfodiesterasa/farmacocinética , Inhibidores de Fosfodiesterasa/uso terapéutico , Unión Proteica , Pirazoles/farmacocinética , Pirazoles/uso terapéutico , Ratas , Relación Estructura-ActividadRESUMEN
Novel siderophore-linked monobactams with in vitro and in vivo anti-microbial activity against MDR Gram-negative pathogens are described.
Asunto(s)
Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Bacterias Gramnegativas/efectos de los fármacos , Infecciones por Bacterias Gramnegativas/tratamiento farmacológico , Monobactamas/farmacología , Animales , Sitios de Unión/efectos de los fármacos , Proteínas Sanguíneas/química , Cristalografía por Rayos X , Relación Dosis-Respuesta a Droga , Infecciones por Bacterias Gramnegativas/microbiología , Humanos , Ratones , Pruebas de Sensibilidad Microbiana , Modelos Moleculares , Estructura Molecular , Monobactamas/síntesis química , Monobactamas/química , Ratas , Relación Estructura-ActividadRESUMEN
Modern drug discovery is contingent on identifying lead compounds and rapidly synthesizing analogues. The use of a common pharmacophore to direct multiple and divergent C-H functionalizations of lead compounds is a particularly attractive approach. Herein, we demonstrate the viability of late-stage diversification through the divergent C-H functionalization of sulfonamides, an important class of pharmacophores found in nearly 200 drugs currently on the market, including the non-steroidal anti-inflammatory blockbuster drug celecoxib. We developed a set of six categorically different sulfonamide C-H functionalization reactions (olefination, arylation, alkylation, halogenation, carboxylation, and carbonylation), each representing a distinct handle for further diversification to reach a large number of analogues. We then performed late-stage, site-selective diversification of a sulfonamide drug candidate containing multiple potentially reactive C-H bonds to synthesize directly novel celecoxib analogues as potential cyclooxygenase-II (COX-2)-specific inhibitors. Together with other recently developed practical directing groups, such as CONHOMe and CONHC(6)F(5), sulfonamide directing groups demonstrate that the auxiliary approach established in asymmetric catalysis can be equally effective in developing broadly useful C-H activation reactions.
Asunto(s)
Inhibidores de la Ciclooxigenasa 2/química , Descubrimiento de Drogas/métodos , Pirazoles/química , Sulfonamidas/química , Alquenos/química , Catálisis , Celecoxib , Inhibidores de la Ciclooxigenasa 2/aislamiento & purificación , Pirazoles/aislamiento & purificación , Sulfonamidas/aislamiento & purificaciónRESUMEN
Serious infections caused by multidrug-resistant (MDR) organisms (Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii) present a critical need for innovative drug development. Herein, we describe the preclinical evaluation of YU253911, 2, a novel γ-lactam siderophore antibiotic with potent antimicrobial activity against MDR Gram-negative pathogens. Penicillin-binding protein (PBP) 3 was shown to be a target of 2 using a binding assay with purified P. aeruginosa PBP3. The specific binding interactions with P. aeruginosa were further characterized with a high-resolution (2.0 Å) X-ray structure of the compound's acylation product in P. aeruginosa PBP3. Compound 2 was shown to have a concentration >1 µg/ml at the 6 h time point when administered intravenously or subcutaneously in mice. Employing a meropenem resistant strain of P. aeruginosa, 2 was shown to have dose-dependent efficacy at 50 and 100 mg/kg q6h dosing in a mouse thigh infection model. Lastly, we showed that a novel γ-lactam and ß-lactamase inhibitor (BLI) combination can effectively lower minimum inhibitory concentrations (MICs) against carbapenem resistant Acinetobacter spp. that demonstrated decreased susceptibility to 2 alone.
Asunto(s)
Antibacterianos/farmacología , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Klebsiella pneumoniae/efectos de los fármacos , Lactamas/farmacología , Sideróforos/farmacología , Acinetobacter baumannii/efectos de los fármacos , Antibacterianos/síntesis química , Antibacterianos/química , Relación Dosis-Respuesta a Droga , Lactamas/síntesis química , Lactamas/química , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Pseudomonas aeruginosa/efectos de los fármacos , Sideróforos/síntesis química , Sideróforos/química , Relación Estructura-ActividadRESUMEN
This report describes the use of Pd(II)/bis-sulfoxide 1 catalyzed intra- and intermolecular allylic C-H amination reactions to rapidly diversify structures containing a sensitive ß-lactam core similar to that found in the monobactam antibiotic Aztreonam. Pharmacologically interesting oxazolidinone, oxazinanone, and linear amine motifs are rapidly installed with predictable and high selectivities under conditions that use limiting amounts of substrate. Additionally, we demonstrate for the first time that intramolecular C-H amination processes may be accelerated using catalytic amounts of a Lewis acid co-catalyst [Cr(III)(salen)Cl 2].
RESUMEN
Treatment of multidrug-resistant Gram-negative bacterial pathogens represents a critical clinical need. Here, we report a novel γ-lactam pyrazolidinone that targets penicillin-binding proteins (PBPs) and incorporates a siderophore moiety to facilitate uptake into the periplasm. The MIC values of γ-lactam YU253434, 1, are reported along with the finding that 1 is resistant to hydrolysis by all four classes of ß-lactamases. The druglike characteristics and mouse PK data are described along with the X-ray crystal structure of 1 binding to its target PBP3.
Asunto(s)
Antibacterianos/farmacología , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Lactamas/química , Sideróforos/química , Animales , Antibacterianos/síntesis química , Antibacterianos/metabolismo , Antibacterianos/farmacocinética , Proteínas Bacterianas/antagonistas & inhibidores , Proteínas Bacterianas/metabolismo , Sitios de Unión , Dominio Catalítico , Cristalografía por Rayos X , Bacterias Gramnegativas/efectos de los fármacos , Semivida , Lactamas/metabolismo , Lactamas/farmacocinética , Lactamas/farmacología , Ratones , Pruebas de Sensibilidad Microbiana , Simulación del Acoplamiento Molecular , Proteínas de Unión a las Penicilinas/antagonistas & inhibidores , Proteínas de Unión a las Penicilinas/metabolismo , Pseudomonas aeruginosa/metabolismo , Sideróforos/metabolismoRESUMEN
A new series of MEK1 inhibitors, the 4-anilino-5-carboxamido-2-pyridones, were designed and synthesized using a combination of medicinal chemistry, computational chemistry, and structural elucidation. The effect of variation in the carboxamide side chain, substitution on the pyridone nitrogen, and replacement of the 4'-iodide were all investigated. This study afforded several compounds which were either equipotent or more potent than the clinical candidate CI-1040 (1) in an isolated enzyme assay, as well as murine colon carcinoma (C26) cells, as measured by suppression of phosphorylated ERK substrate. Most notably, pyridone 27 was found to be more potent than 1 in vitro and produced a 100% response rate at a lower dose than 1, when tested for in vivo efficacy in animals bearing C26 tumors.
Asunto(s)
Amidas/síntesis química , Compuestos de Anilina/síntesis química , Antineoplásicos/síntesis química , MAP Quinasa Quinasa 1/antagonistas & inhibidores , MAP Quinasa Quinasa 2/antagonistas & inhibidores , Piridonas/síntesis química , Amidas/química , Amidas/farmacología , Compuestos de Anilina/química , Compuestos de Anilina/farmacología , Animales , Antineoplásicos/química , Antineoplásicos/farmacología , Benzamidas/farmacología , Línea Celular Tumoral , Ensayos de Selección de Medicamentos Antitumorales , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , MAP Quinasa Quinasa 1/química , MAP Quinasa Quinasa 2/química , Masculino , Ratones , Modelos Moleculares , Trasplante de Neoplasias , Fosforilación , Piridonas/química , Piridonas/farmacología , Ratas , Relación Estructura-ActividadRESUMEN
Fluoride is a ubiquitous anion that inhibits a wide variety of metabolic processes. Here, we report the identification of a series of compounds that enhance fluoride toxicity in Escherichia coli and Streptococcus mutans. These molecules were isolated by using a high-throughput screen (HTS) for compounds that increase intracellular fluoride levels as determined via a fluoride riboswitch reporter fusion construct. A series of derivatives were synthesized to examine structure-activity relationships, leading to the identification of compounds with improved activity. Thus, we demonstrate that small molecule fluoride toxicity agonists can be identified by HTS from existing chemical libraries by exploiting a natural fluoride riboswitch. In addition, our findings suggest that some molecules might be further optimized to function as binary antibacterial agents when combined with fluoride.
Asunto(s)
Antibacterianos/química , Fluoruros/química , Fluoruros/toxicidad , Antibacterianos/síntesis química , Antibacterianos/farmacología , Escherichia coli/efectos de los fármacos , Fluoruros/agonistas , Ensayos Analíticos de Alto Rendimiento , Pruebas de Sensibilidad Microbiana , Riboswitch , Streptococcus mutans/efectos de los fármacos , Relación Estructura-ActividadRESUMEN
This study demonstrates that ΔlogP(oct-tol) (difference between logP(octanol) and logP(toluene)) describes compounds propensity to form intramolecular hydrogen bonds (IMHB) and may be considered a privileged molecular descriptor for use in drug discovery and for prediction of IMHB in drug candidates. We identified experimental protocols for acquiring reliable ΔlogP(oct-tol) values on a set of compounds representing IMHB motifs most prevalent in medicinal chemistry, mainly molecules capable of forming 6-, 7-member IMHB rings. Furthermore, computational ΔlogP(oct-tol) values obtained with COSMO-RS software provided a good estimate of experimental results and can be used prospectively to assess IMHB. The proposed interpretation method based on ΔlogP(oct-tol) data allowed categorization of the compounds into 2 groups: with high propensity to form IMHB and poor propensity or poor relevance of IMHB. The relative (1)H NMR chemical shift of an exchangeable proton was used to verify presence of IMHB and to validate the IMHB interpretation scheme.
Asunto(s)
Descubrimiento de Drogas/métodos , Octanoles/química , Tolueno/química , Química Farmacéutica , Cristalografía por Rayos X , Enlace de Hidrógeno , Modelos Moleculares , Conformación Molecular , Reproducibilidad de los Resultados , Programas InformáticosRESUMEN
Herein we describe the structure-aided design and synthesis of a series of pyridone-conjugated monobactam analogues with in vitro antibacterial activity against clinically relevant Gram-negative species including Pseudomonas aeruginosa , Klebsiella pneumoniae , and Escherichia coli . Rat pharmacokinetic studies with compound 17 demonstrate low clearance and low plasma protein binding. In addition, evidence is provided for a number of analogues suggesting that the siderophore receptors PiuA and PirA play a role in drug uptake in P. aeruginosa strain PAO1.
Asunto(s)
Antibacterianos/farmacología , Bacterias Gramnegativas/efectos de los fármacos , Monobactamas/farmacología , Piridonas/farmacología , Animales , Antibacterianos/química , Antibacterianos/farmacocinética , Escherichia coli/efectos de los fármacos , Concentración 50 Inhibidora , Klebsiella pneumoniae/efectos de los fármacos , Masculino , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Monobactamas/química , Monobactamas/farmacocinética , Pseudomonas aeruginosa/efectos de los fármacos , Piridonas/química , Piridonas/farmacocinética , Ratas , Ratas WistarRESUMEN
Tandem reaction sequences that selectively convert multiple C-H bonds of abundant hydrocarbon feedstocks to functionalized materials enable rapid buildup of molecular complexity in an economical way. A tandem C-H amination/vinylic C-H arylation reaction sequence is described under Pd(II)/sulfoxide-catalysis that furnishes a wide range of α- and ß-homophenylalanine precursors from commodity α-olefins and readily available aryl boronic acids. General routes to enantiopure amino acid esters and densely functionalized homophenylalanine derivatives are demonstrated.
Asunto(s)
Alquenos/química , Aminoácidos/síntesis química , Aminación , Aminoácidos/química , Catálisis , Estructura Molecular , EstereoisomerismoRESUMEN
Thymidylate kinase (TMK) is a potential chemotherapeutic target because it is directly involved in the synthesis of an essential component, thymidine triphosphate, in DNA replication. All reported TMK inhibitors are thymidine analogues, which might retard their development as potent therapeutics due to cell permeability and off-target activity against human TMK. A small molecule hit (1, IC(50) = 58 µM), which has reasonable inhibition potency against Pseudomonas aeruginosa TMK (PaTMK), was identified by the analysis of the binding mode of thymidine or TP(5)A in a PaTMK homology model. This hit (1) was cocrystallized with PaTMK, and several potent PaTMK inhibitors (leads, 46, 47, 48, and 56, IC(50) = 100-200 nM) were synthesized using computer-aided design approaches including virtual synthesis/screening, which was used to guide the design of inhibitors. The binding mode of the optimized leads in PaTMK overlaps with that of other bacterial TMKs but not with human TMK, which shares few common features with the bacterial enzymes. Therefore, the optimized TMK inhibitors described here should be useful for the development of antibacterial agents targeting TMK without undesired off-target effects. In addition, an inhibition mechanism associated with the LID loop, which mimics the process of phosphate transfer from ATP to dTMP, was proposed based on X-ray cocrystal structures, homology models, and structure-activity relationship results.
Asunto(s)
Antibacterianos/síntesis química , Imidazoles/síntesis química , Nucleósido-Fosfato Quinasa/antagonistas & inhibidores , Pseudomonas aeruginosa/enzimología , Piridinas/síntesis química , Pirimidinas/síntesis química , Timidina/química , Antibacterianos/química , Antibacterianos/farmacología , Cristalografía por Rayos X , Humanos , Imidazoles/química , Imidazoles/farmacología , Pruebas de Sensibilidad Microbiana , Modelos Moleculares , Conformación Molecular , Imitación Molecular , Nucleósido-Fosfato Quinasa/química , Unión Proteica , Pseudomonas aeruginosa/efectos de los fármacos , Piridinas/química , Piridinas/farmacología , Pirimidinas/química , Pirimidinas/farmacología , Alineación de SecuenciaRESUMEN
In this paper, we present the synthesis and SAR as well as selectivity, pharmacokinetic, and infection model data for representative analogues of a novel series of potent antibacterial LpxC inhibitors represented by hydroxamic acid.
Asunto(s)
Amidohidrolasas/antagonistas & inhibidores , Antibacterianos/síntesis química , Compuestos de Bifenilo/síntesis química , Ácidos Hidroxámicos/síntesis química , Éteres Fenílicos/síntesis química , Infecciones por Pseudomonas/tratamiento farmacológico , Sulfuros/síntesis química , Sulfonas/síntesis química , Animales , Antibacterianos/química , Antibacterianos/farmacología , Compuestos de Bifenilo/química , Compuestos de Bifenilo/farmacología , Dominio Catalítico , Cristalografía por Rayos X , Farmacorresistencia Bacteriana , Enlace de Hidrógeno , Ácidos Hidroxámicos/química , Ácidos Hidroxámicos/farmacología , Ratones , Modelos Moleculares , Conformación Molecular , Éteres Fenílicos/química , Éteres Fenílicos/farmacología , Pseudomonas aeruginosa , Ratas , Estereoisomerismo , Relación Estructura-Actividad , Sulfuros/química , Sulfuros/farmacología , Sulfonas/química , Sulfonas/farmacologíaRESUMEN
An efficient method was developed for the synthesis of 2-methylene-4-substituted ethyl butyrates via cyclopropyl opening followed by a Wittig reaction. The desired products were formed in a two-step, one-pot reaction sequence. Alternatively, the key intermediate ylide 2 was isolable and could be stored under oxygen-free conditions and subsequently utilized. A variety of nucleophiles were found to open the commercially available cyclopropane 1. The resulting ylide reacted with aldehydes to provide E-olefinic products.
Asunto(s)
Boratos/química , Compuestos Organofosforados/química , Aldehídos/química , Ciclización , Estructura MolecularRESUMEN
A novel class of reversible inhibitors of Interleukin-1beta-converting enzyme (ICE, caspase-1) were discovered by iterative structure-based design. Guided by the X-ray crystal structure of analogues 1, 7 and 10 bound to ICE, we have designed a nonpeptide series of small molecule inhibitors. These compounds incorporate an arylsulfonamide moiety which replaces Val-His unit (P3-P2 residues) amino acids of the native substrate. The synthesis of the core structure, structure-activity relationships (SARs), and proposed binding orientation based on molecular modeling studies for this series of ICE inhibitors are described.