Blount K.F.,Yale University |
Blount K.F.,BioRelix |
Megyola C.,Yale University |
Plummer M.,Yale University |
And 14 more authors.
Antimicrobial Agents and Chemotherapy | Year: 2015
Novel mechanisms of action and new chemical scaffolds are needed to rejuvenate antibacterial drug discovery, and riboswitch regulators of bacterial gene expression are a promising class of targets for the discovery of new leads. Herein, we report the characterization of 5-(3-(4-fluorophenyl)butyl)-7,8-dimethylpyrido[3,4-b]quinoxaline-1,3(2H,5H)-dione (5FDQD) - an analog of riboflavin that was designed to bind riboswitches that naturally recognize the essential coenzyme flavin mononucleotide (FMN) and regulate FMN and riboflavin homeostasis. In vitro, 5FDQD and FMN bind to and trigger the function of an FMN riboswitch with equipotent activity. MIC and time-kill studies demonstrated that 5FDQD has potent and rapidly bactericidal activity against Clostridium difficile. In C57BL/6 mice, 5FDQD completely prevented the onset of lethal antibiotic-induced C. difficile infection (CDI). Against a panel of bacteria representative of healthy bowel flora, the antibacterial selectivity of 5FDQD was superior to currently marketed CDI therapeutics, with very little activity against representative strains from the Bacteroides, Lactobacillus, Bifidobacterium, Actinomyces, and Prevotella genera. Accordingly, a single oral dose of 5FDQD caused less alteration of culturable cecal flora in mice than the comparators. Collectively, these data suggest that 5FDQD or closely related analogs could potentially provide a high rate of CDI cure with a low likelihood of infection recurrence. Future studies will seek to assess the role of FMN riboswitch binding to the mechanism of 5FDQD antibacterial action. In aggregate, our results indicate that riboswitch-binding antibacterial compounds can be discovered and optimized to exhibit activity profiles that merit preclinical and clinical development as potential antibacterial therapeutic agents. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
PubMed | Kalexsyn Inc. and DeuteRx LLC andover
Type: Journal Article | Journal: Proceedings of the National Academy of Sciences of the United States of America | Year: 2015
Therapeutics developed and sold as racemates can exhibit a limited therapeutic index because of side effects resulting from the undesired enantiomer (distomer) and/or its metabolites, which at times, forces researchers to abandon valuable scaffolds. Therefore, most chiral drugs are developed as single enantiomers. Unfortunately, the development of some chirally pure drug molecules is hampered by rapid in vivo racemization. The class of compounds known as immunomodulatory drugs derived from thalidomide is developed and sold as racemates because of racemization at the chiral center of the 3-aminoglutarimide moiety. Herein, we show that replacement of the exchangeable hydrogen at the chiral center with deuterium allows the stabilization and testing of individual enantiomers for two thalidomide analogs, including CC-122, a compound currently in human clinical trials for hematological cancers and solid tumors. Using deuterium-enabled chiral switching (DECS), in vitro antiinflammatory differences of up to 20-fold are observed between the deuterium-stabilized enantiomers. In vivo, the exposure is dramatically increased for each enantiomer while they retain similar pharmacokinetics. Furthermore, the single deuterated enantiomers related to CC-122 exhibit profoundly different in vivo responses in an NCI-H929 myeloma xenograft model. The (-)-deuterated enantiomer is antitumorigenic, whereas the (+)-deuterated enantiomer has little to no effect on tumor growth. The ability to stabilize and differentiate enantiomers by DECS opens up a vast window of opportunity to characterize the class effects of thalidomide analogs and improve on the therapeutic promise of other racemic compounds, including the development of safer therapeutics and the discovery of new mechanisms and clinical applications for existing therapeutics.
PubMed | Lonza AG, University of Graz, Kalexsyn Inc. and DuPont Company
Type: Journal Article | Journal: Chemistry (Weinheim an der Bergstrasse, Germany) | Year: 2016
We report an operationally simple and rapid continuous flow radical C-C bond formation under Minisci-type reaction conditions. The transformations are performed at or below room temperature employing hydrogen peroxide (H
Walker D.,Kalexsyn Inc. |
Rogier D.J.,Kalexsyn Inc.
Synthesis (Germany) | Year: 2013
Thiomorpholine and thiomorpholine 1,1-dioxide are important building blocks in medicinal chemistry research, and some analogues containing these moieties have entered human clinical trials. Analogues containing bridged bicyclic thiomorpholines have also shown interesting biological profiles. 3-Thia-6-azabicyclo[3.1.1]heptane, 3-thia-8-azabicyclo[3.2.1]octane, and their corresponding 1,1-dioxide counterparts were prepared as novel bicyclic thiomorpholine building blocks. Each heterocycle was synthesized from an inexpensive starting material by straightforward chemistry. © Georg Thieme Verlag Stuttgart, New York.
Lipshutz B.H.,University of California at Santa Barbara |
Ghorai S.,University of California at Santa Barbara |
Abela A.R.,University of California at Santa Barbara |
Moser R.,University of California at Santa Barbara |
And 5 more authors.
Journal of Organic Chemistry | Year: 2011
An environmentally benign surfactant (TPGS-750-M), a diester composed of racemic α-tocopherol, MPEG-750, and succinic acid, has been designed and readily prepared as an effective nanomicelle-forming species for general use in metal-catalyzed cross-coupling reactions in water. Several "name" reactions, including Heck, Suzuki-Miyaura, Sonogashira, and Negishi-like couplings, have been studied using this technology, as have aminations, C-H activations, and olefin metathesis reactions. Physical data in the form of DLS and cryo-TEM measurements suggest that particle size and shape are key elements in achieving high levels of conversion and, hence, good isolated yields of products. This new amphiphile will soon be commercially available. © 2011 American Chemical Society.
Walker D.P.,Kalexsyn Inc. |
Eklov B.M.,Kalexsyn Inc. |
Bedore M.W.,Kalexsyn Inc.
Synthesis (Germany) | Year: 2012
Bridged bicyclic morpholines are important building blocks in medicinal chemistry research. The bicyclic morpholine 3-oxa-6-azabicylo[3.1.1]heptane (3a) is of particular interest as a morpholine isostere because it is achiral and shows similar lipophilicity to that of morpholine, based on the cLogP of a derived analogue. The first synthesis of morpholine 3a (tosylate salt) is described; the seven-step sequence begins with inexpensive starting materials and uses straightforward chemistry. © Georg Thieme Verlag Stuttgart • New York.
Schlauderer F.,Ludwig Maximilians University of Munich |
Lammens K.,Ludwig Maximilians University of Munich |
Nagel D.,Helmholtz Center Munich |
Vincendeau M.,Helmholtz Center Munich |
And 7 more authors.
Angewandte Chemie - International Edition | Year: 2013
Second site: In the crystal structure of human MALT1casp-Ig3 (mucosa-associated lymphoid tissue lymphoma translocation protein 1) in complex with the tricyclic phenothiazine derivative thioridazine (violet in the picture), the inhibitor is bound in a hydrophobic pocket far from the active site. This explains the action of phenothiazine derivatives as noncompetitive, reversible inhibitors. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Walker D.P.,Kalexsyn Inc. |
Bedore M.W.,Kalexsyn Inc.
Tetrahedron Letters | Year: 2012
Bridged bicyclic piperazines are important building blocks in medicinal chemistry research. The bicyclic piperazine 3,6-diazabicylo[3.1.1]heptane is of particular interest as a piperazine isostere because it is achiral and shows similar lipophilicity to that of piperazine based on the c Log P of a derived analog. A concise synthesis of N 3- and N 6-monoprotected 3,6-diazabicyclo[3.1.1]heptanes 2d and 2e, respectively, is described. The seven step sequence begins with inexpensive starting materials and uses straightforward chemistry. © 2012 Elsevier Ltd. All rights reserved.
PubMed | Actelion Pharmaceuticals and Kalexsyn Inc.
Type: Journal Article | Journal: Journal of medicinal chemistry | Year: 2016
A series of dihydropyrazole derivatives was developed as potent, selective, and brain-penetrating T-type calcium channel blockers. An optimized derivative, compound 6c, was advanced to in vivo studies, where it demonstrated efficacy in the WAG/Rij rat model of generalized nonconvulsive, absence-like epilepsy. Compound 6c was not efficacious in the basolateral amygdala kindling rat model of temporal lobe epilepsy, and it led to prolongation of the PR interval in ECG recordings in rodents.
PubMed | Aureogen Biosciences, Inc. and Kalexsyn Inc.
Type: Journal Article | Journal: ACS medicinal chemistry letters | Year: 2015
The natural product aureobasidin A (AbA) is a potent, well-tolerated antifungal agent with robust efficacy in animals. Although native AbA is active against a number of fungi, it has little activity against Aspergillus fumigatus, an important human pathogen, and attempts to improve the activity against this organism by structural modifications have to date involved chemistries too complex for continued development. This report describes novel chemistry for the modification of AbA. The key step involves functionalization of the phenylalanine residues in the compound by iridium-catalyzed borylation. This is followed by displacement of the pinacol boron moiety to form the corresponding bromide or iodide and substitution by Suzuki biaryl coupling. The approach allows for synthesis of a truly wide range of derivatives and has produced compounds with A. fumigatus minimal inhibitory concentrations (MIC) of <0.5 g/mL. The approach is readily adaptable to large-scale synthesis and industrial production.