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One-Pot Oxidative Amidation of Aldehydes via the Generation of Nitrile Imine Intermediates. J Org Chem 2024. [PMID: 38778786 DOI: 10.1021/acs.joc.4c00575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
A one-pot procedure for the oxidative amidation of aldehydes via the in situ generation of reactive nitrile imine (NI) intermediates has been developed. Distinct from our progenitor processes, mechanistic and control experiments revealed that the NI undergoes rapid oxidation to an acyl diazene species, which then facilitates N-acylation of an amine. A range of substrates have been explored, including application in the synthesis of pharmaceutically relevant compounds.
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2
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Synthesis and Evaluation of Small Molecule Inhibitors of the Androgen Receptor N-Terminal Domain. ACS Med Chem Lett 2023; 14:1800-1806. [PMID: 38116409 PMCID: PMC10726465 DOI: 10.1021/acsmedchemlett.3c00426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 11/10/2023] [Accepted: 11/13/2023] [Indexed: 12/21/2023] Open
Abstract
The androgen receptor (AR) is central to prostate cancer pathogenesis and has been extensively validated as a drug target. However, small-molecule anti-androgen therapies remain limited due to resistance and will eventually fail to suppress tumor growth, resulting in progression to castration-resistant prostate cancer (CRPC). The intrinsically disordered N-terminal domain (NTD) is crucial for AR transactivation and has been investigated as a suitable target in the presence of ligand binding domain mutations. A screening campaign identified biaryl isoxazole compound 7 as a weak inhibitor of the AR NTD. A library of biaryl analogues were synthesized, and their biological activities were assessed in a VCaP cell-based luciferase reporter gene assay. A structure-activity relationship (SAR) study revealed that indazole analogue 16 exhibited increased potency and favorable physicochemical properties with a benchmarked pharmacokinetic profile, providing a suitable starting point for further optimization of 16 as a CRPC therapeutic in the presence of AR mutations.
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3
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Computer vision as a new paradigm for monitoring of solution and solid phase peptide synthesis. Chem Sci 2023; 14:11872-11880. [PMID: 37920332 PMCID: PMC10619640 DOI: 10.1039/d3sc01383a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 10/04/2023] [Indexed: 11/04/2023] Open
Abstract
We report a strategy for the camera-enabled non-contact colourimetric reaction monitoring and optimisation of amide bond formation, mediated by coupling reagents. For amide bond formation in solution phase, investigation of reactions mediated by HATU, PyAOP, and DIC/Oxyma evidenced correlations between colour parameters extracted from video data and conversion to amide product measured by off-line HPLC analysis of concentration. These correlations, supported by mutual information analysis, were further investigated using video recordings of solid phase peptide synthesis (SPPS), co-analysed by off-line HPLC to track remaining unreacted substrate in solution. An optimisation method of coupling time in SPPS was derived from ΔE (a measurement of colour contrast), giving comparable isolated peptide yield and purity at 65-95% reduced overall reaction time. The same colour data enabled data-rich monitoring of reaction rate attenuation, consisted with computationally-derived measures of amino acid steric bulk. These findings provide a foundation for exploring the use of camera technology and computer vision towards automated and online mechanistic profiling of SPPS.
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4
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Current and emerging approaches to noncompetitive AR inhibition. Med Res Rev 2023; 43:1701-1747. [PMID: 37062876 DOI: 10.1002/med.21961] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 03/14/2023] [Accepted: 03/28/2023] [Indexed: 04/18/2023]
Abstract
The androgen receptor (AR) has been shown to be a key determinant in the pathogenesis of castration-resistant prostate cancer (CRPC). The current standard of care therapies targets the ligand-binding domain of the receptor and can afford improvements to life expectancy often only in the order of months before resistance occurs. Emerging preclinical and clinical compounds that inhibit receptor activity via differentiated mechanisms of action which are orthogonal to current antiandrogens show promise for overcoming treatment resistance. In this review, we present an authoritative summary of molecules that noncompetitively target the AR. Emerging small molecule strategies for targeting alternative domains of the AR represent a promising area of research that shows significant potential for future therapies. The overall quality of lead candidates in the area of noncompetitive AR inhibition is discussed, and it identifies the key chemotypes and associated properties which are likely to be, or are currently, positioned to be first in human applications.
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5
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Functionalized Tetrazoles as Latent Active Esters in the Synthesis of Amide Bonds. Org Lett 2022; 24:9491-9496. [PMID: 36524745 PMCID: PMC9806851 DOI: 10.1021/acs.orglett.2c03971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We report the use of N-2,4-dinitrophenyltetrazoles as latent active esters (LAEs) in the synthesis of amide bonds. Activating the tetrazole generates an HOBt-type active ester without the requirement for exogenous coupling agents. The methodology was widely applicable to a range of substrates, with up to quantitative yields obtained. The versatility and functional group tolerance were exemplified with the one-step synthesis of various pharmaceutical agents and the N-acylation of resin-bound peptides.
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6
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Identification and Optimization of a Ligand-Efficient Benzoazepinone Bromodomain and Extra Terminal (BET) Family Acetyl-Lysine Mimetic into the Oral Candidate Quality Molecule I-BET432. J Med Chem 2022; 65:15174-15207. [DOI: 10.1021/acs.jmedchem.2c01102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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7
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Author Correction: Cancer-associated fibroblasts require proline synthesis by PYCR1 for the deposition of pro-tumorigenic extracellular matrix. Nat Metab 2022; 4:1084. [PMID: 35927357 PMCID: PMC9398906 DOI: 10.1038/s42255-022-00632-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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8
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A type IV Autotaxin inhibitor ameliorates acute liver injury and nonalcoholic steatohepatitis. EMBO Mol Med 2022; 14:e16333. [PMID: 35833384 PMCID: PMC9449594 DOI: 10.15252/emmm.202216333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/29/2022] [Accepted: 06/30/2022] [Indexed: 11/09/2022] Open
Abstract
The lysophosphatidic acid (LPA) signaling axis is an important but rather underexplored pathway in liver disease. LPA is predominantly produced by Autotaxin (ATX) that has gained significant attention with an impressive number of ATX inhibitors (type I-IV) reported. Here, we evaluated the therapeutic potential of a (yet unexplored) type IV inhibitor, Cpd17, in liver injury. We first confirmed the involvement of the ATX-LPA signaling axis in human and murine diseased livers. Then, we evaluated the effects of Cpd17, in comparison with the classic type I inhibitor PF8380, in vitro, where Cpd17 showed higher efficacy. Thereafter, we characterized the mechanism-of-action of both inhibitors and found that Cpd17 was more potent in inhibiting RhoA-mediated cytoskeletal remodeling, and phosphorylation of MAPK/ERK and AKT/PKB. Finally, the therapeutic potential of Cpd17 was investigated in CCl4 -induced acute liver injury and diet-induced nonalcoholic steatohepatitis, demonstrating an excellent potential of Cpd17 in reducing liver injury in both disease models in vivo. We conclude that ATX inhibition, by type IV inhibitor in particular, has an excellent potential for clinical application in liver diseases.
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9
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Cancer-associated fibroblasts require proline synthesis by PYCR1 for the deposition of pro-tumorigenic extracellular matrix. Nat Metab 2022; 4:693-710. [PMID: 35760868 PMCID: PMC9236907 DOI: 10.1038/s42255-022-00582-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 05/10/2022] [Indexed: 12/21/2022]
Abstract
Elevated production of collagen-rich extracellular matrix is a hallmark of cancer-associated fibroblasts (CAFs) and a central driver of cancer aggressiveness. Here we find that proline, a highly abundant amino acid in collagen proteins, is newly synthesized from glutamine in CAFs to make tumour collagen in breast cancer xenografts. PYCR1 is a key enzyme for proline synthesis and highly expressed in the stroma of breast cancer patients and in CAFs. Reducing PYCR1 levels in CAFs is sufficient to reduce tumour collagen production, tumour growth and metastatic spread in vivo and cancer cell proliferation in vitro. Both collagen and glutamine-derived proline synthesis in CAFs are epigenetically upregulated by increased pyruvate dehydrogenase-derived acetyl-CoA levels. PYCR1 is a cancer cell vulnerability and potential target for therapy; therefore, our work provides evidence that targeting PYCR1 may have the additional benefit of halting the production of a pro-tumorigenic extracellular matrix. Our work unveils new roles for CAF metabolism to support pro-tumorigenic collagen production.
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10
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Structure-Based Design of a Novel Class of Autotaxin Inhibitors Based on Endogenous Allosteric Modulators. J Med Chem 2022; 65:6338-6351. [PMID: 35440138 PMCID: PMC9059126 DOI: 10.1021/acs.jmedchem.2c00368] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Autotaxin (ATX) facilitates the hydrolysis of lysophosphatidylcholine to lysophosphatidic acid (LPA), a bioactive phospholipid, which facilitates a diverse range of cellular effects in multiple tissue types. Abnormal LPA expression can lead to the progression of diseases such as cancer and fibrosis. Previously, we identified a potent ATX steroid-derived hybrid (partially orthosteric and allosteric) inhibitor which did not form interactions with the catalytic site. Herein, we describe the design, synthesis, and biological evaluation of a focused library of novel steroid-derived analogues targeting the bimetallic catalytic site, representing an entirely unique class of ATX inhibitors of type V designation, which demonstrate significant pathway-relevant biochemical and phenotypic biological effects. The current compounds modulated LPA-mediated ATX allostery and achieved indirect blockage of LPA1 internalization, in line with the observed reduction in downstream signaling cascades and chemotaxis induction. These novel type V ATX inhibitors represent a promising tool to inactivate the ATX-LPA signaling axis.
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11
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Clonal Expansion of Stem/Progenitor Cells in Cancer, Fibrotic Diseases, and Atherosclerosis, and CD47 Protection of Pathogenic Cells. Annu Rev Med 2022; 73:307-320. [PMID: 35084991 DOI: 10.1146/annurev-med-042420-104436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We proposed and demonstrated that myelogenous leukemia has a preleukemic phase. In the premalignant phase, normal hematopoietic stem cells (HSCs) gradually accumulate mutations leading to HSC clonal expansion, resulting in the emergence of leukemic stem cells (LSCs). Here, we show that preleukemic HSCs are the basis of clonal hematopoiesis, as well as late-onset blood diseases (chronic-phase chronic myeloid leukemia, myeloproliferative neoplasms, and myelodysplastic disease). The clones at some point each trigger surface expression of "eat me" signals for macrophages, and in the clones and their LSC progeny, this is countered by upregulation of "don't eat me" signals for macrophages such as CD47,opening the possibility of CD47-based therapies. We include evidence that similar processes result in fibroblast expansion in a variety of fibrotic diseases, and arterial smooth muscle clonal expansion is a basis of atherosclerosis, including upregulation of both "eat me" and "don't eat me" molecules on the pathogenic cells.
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12
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Synthesis of an allylic gem-difluoromethylene building block via radical-mediated difluorocyclopropane ring opening. Tetrahedron Lett 2021. [DOI: 10.1016/j.tetlet.2021.153344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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13
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Abstract
AbstractNitrilium betaine 1,3-dipoles are ubiquitous reagents in organic chemistry, with applications ranging from natural product synthesis to materials science. Given the high reactivity of these zwitterionic motifs, they are invariably generated in situ from a suitable precursor, prior to use. This short review summarises the recent progress in the development of modern approaches towards the formation of these 1,3-dipoles, and their applications within a diverse range of fields.1 Introduction2 Nitrile Ylides2.1 2H-Azirine Rearrangement2.2 Addition of Nitriles to Carbenes3 Nitrile Imines3.1 2,5-Tetrazole Thermolysis3.2 2,5-Tetrazole Photolysis3.3 Diaryl Sydnone Photolysis4 Nitrile Oxides4.1 Hypervalent Iodine4.2 The Nitroso Radical4.3 Green Chemistry Approaches4.4 Other Approaches5 Conclusions
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14
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15
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UV-Induced 1,3,4-Oxadiazole Formation from 5-Substituted Tetrazoles and Carboxylic Acids in Flow. Chemistry 2020; 26:14866-14870. [PMID: 32786060 PMCID: PMC7756889 DOI: 10.1002/chem.202002896] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 08/11/2020] [Indexed: 12/27/2022]
Abstract
A range of 1,3,4-oxadiazoles have been synthesized using a UV-B activated flow approach starting from carboxylic acids and 5-substituted tetrazoles. The application of UV light represents an attractive alternative to the traditional thermolytic approach and has demonstrated comparable efficiency and versatility, with a diverse substrate scope, including the incorporation of highly substituted amino acids.
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16
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17
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Transition-Metal-Free Coupling of 1,3-Dipoles and Boronic Acids as a Sustainable Approach to C-C Bond Formation. Chemistry 2020; 26:10591-10597. [PMID: 32428258 PMCID: PMC7496359 DOI: 10.1002/chem.202001590] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 05/07/2020] [Indexed: 12/19/2022]
Abstract
The need for alternative, complementary approaches to enable C-C bond formation within organic chemistry is an on-going challenge in the area. Of particular relevance are transformations that proceed in the absence of transition-metal reagents. In the current study, we report a comprehensive investigation of the coupling of nitrile imines and aryl boronic acids as an approach towards sustainable C-C bond formation. In situ generation of the highly reactive 1,3-dipole facilitates a Petasis-Mannich-type coupling via a nucleophilic boronate complex. The introduction of hydrazonyl chlorides as a complementary nitrile imine source to the 2,5-tetrazoles previously reported by our laboratory further broadens the scope of the approach. Additionally, we exemplify for the first time the extension of this protocol into another 1,3-dipole, through the synthesis of aryl ketone oximes from aryl boronic acids and nitrile N-oxides.
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18
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Design and Development of a Macrocyclic Series Targeting Phosphoinositide 3-Kinase δ. ACS Med Chem Lett 2020; 11:1386-1391. [PMID: 32676144 DOI: 10.1021/acsmedchemlett.0c00061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 06/03/2020] [Indexed: 11/29/2022] Open
Abstract
A macrocyclization approach has been explored on a series of benzoxazine phosphoinositide 3-kinase δ inhibitors, resulting in compounds with improved potency, permeability, and in vivo clearance while maintaining good solubility. The thermodynamics of binding was explored via surface plasmon resonance, and the binding of lead macrocycle 19 was found to be almost exclusively entropically driven compared with progenitor 18, which demonstrated both enthalpic and entropic contributions. The pharmacokinetics of macrocycle 19 was also explored in vivo, where it showed reduced clearance when compared with the progenitor 18. This work adds to the growing body of evidence that macrocyclization could provide an alternative and complementary approach to the design of small-molecule inhibitors, with the potential to deliver differentiated properties.
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19
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One-Pot Suzuki-Hydrogenolysis Protocol for the Modular Synthesis of 2,5-Diaryltetrazoles. J Org Chem 2020; 85:7413-7423. [PMID: 32392054 PMCID: PMC7304064 DOI: 10.1021/acs.joc.0c00807] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Indexed: 12/20/2022]
Abstract
2,5-Diaryltetrazoles are a diverse range of compounds of considerable interest within the field of photochemistry as a valuable precursor of the nitrile imine 1,3-dipole. Current literature approaches toward this heterocycle remain unsuitable for the practical synthesis of a library of these derivatives. Herein, we disclose the development of a modular approach toward 2,5-diaryltetrazoles compatible with an array-type protocol, facilitated by a tandem Suzuki-hydrogenolysis approach.
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20
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Abstract
An operationally simple E → Z isomerization of activated dienes, based on the β-ionyl motif intrinsic to retinal, is reported using inexpensive (-)-riboflavin (vitamin B2) under irradiation at 402 nm. Selective energy transfer from photoexcited (-)-riboflavin to the starting E-isomer enables geometrical isomerization. Since the analogous process with the Z-isomer is inefficient, microscopic reversibility is circumvented, thereby enabling a directional isomerization to generate the contra-thermodynamic product (up to 99% yield, up to 99:1 Z/E). Prudent choice of photocatalyst enables chemoselective isomerization to be achieved in both inter- and intramolecular systems. The principles established from this study, together with a molecular editing approach, have facilitated the development of a regioselective isomerization of a truncated triene based on the retinal scaffold.
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21
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Metal-free C-C bond formation via coupling of nitrile imines and boronic acids. Chem Sci 2019; 10:10412-10416. [PMID: 32110332 PMCID: PMC6988605 DOI: 10.1039/c9sc03032h] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 09/16/2019] [Indexed: 12/20/2022] Open
Abstract
The challenges of developing sustainable methods of carbon-carbon bond formation remains a topic of considerable importance in synthetic chemistry. Capitalizing on the highly reactive nature of the nitrile imine 1,3-dipole, we have developed a novel metal-free coupling of this species with aryl boronic acids. Photochemical generation of a nitrile imine intermediate and trapping with a palette of boronic acids enabled rapid and facile access to a broad library of more than 25 hydrazone derivatives in up to 92% yield, forming a carbon-carbon bond in a metal free fashion. This represents the first reported example of direct reaction between boronic acids and a 1,3-dipole.
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22
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An assessment of irrigated rice production energy efficiency and environmental footprint with in-field and off-field rice straw management practices. Sci Rep 2019; 9:16887. [PMID: 31729404 PMCID: PMC6858447 DOI: 10.1038/s41598-019-53072-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 10/28/2019] [Indexed: 11/09/2022] Open
Abstract
The research provided scientific evidences for improved rice straw management. Rice cultivation with in-field burning of rice straw is the worst option with the lowest energy efficiency and highest air pollution emission. This article comprises a comparative assessment of energy efficiency and the environmental footprint of rice production using four different rice straw management scenarios, namely, straw retained, straw burned, partial straw removal, and complete straw removal. Paddy yield, grain quality, and energy balance were assessed for two seasons while greenhouse gas emissions (GHGE) were measured weekly starting from land preparation through to the cropping and fallow period. Despite the added energy requirements in straw collection and transport, the use of collected rice straw for mushroom production can increase the net energy obtained from rice production systems by 10-15% compared to burning straw in the field. Partial and complete removal of rice straw reduces GHGE by 30% and 40% compared to complete straw retention, respectively.
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23
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A fragment-like approach to PYCR1 inhibition. Bioorg Med Chem Lett 2019; 29:2626-2631. [PMID: 31362921 DOI: 10.1016/j.bmcl.2019.07.047] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 07/23/2019] [Accepted: 07/24/2019] [Indexed: 11/23/2022]
Abstract
Pyrroline-5-carboxylate reductase 1 (PYCR1) is the final enzyme involved in the biosynthesis of proline and has been found to be upregulated in various forms of cancer. Due to the role of proline in maintaining the redox balance of cells and preventing apoptosis, PYCR1 is emerging as an attractive oncology target. Previous PYCR1 knockout studies led to a reduction in tumor growth. Accordingly, a small molecule inhibitor of PYCR1 could lead to new treatments for cancer, and a focused screening effort identified pargyline as a fragment-like hit. We report the design and synthesis of the first tool compounds as PYCR1 inhibitors, derived from pargyline, which were assayed to assess their ability to attenuate the production of proline. Structural activity studies have revealed the key determinants of activity, with the most potent compound (4) showing improved activity in vitro in enzyme (IC50 = 8.8 µM) and pathway relevant effects in cell-based assays.
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A reappraisal of the Ni-[(Benzylprolyl)amino]benzophenone complex in the synthesis of α,α-disubstituted amino acid derivatives. Tetrahedron 2019. [DOI: 10.1016/j.tet.2019.130485] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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25
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Developing Innovative, Robust and Affordable Medical Linear Accelerators for Challenging Environments. Clin Oncol (R Coll Radiol) 2019; 31:352-355. [DOI: 10.1016/j.clon.2019.02.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 12/08/2018] [Accepted: 01/15/2019] [Indexed: 12/21/2022]
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26
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Abstract
Palladium-catalyzed bond-forming reactions, such as the Suzuki–Miyaura and Mizoroki–Heck reactions, are some of the most broadly utilized reactions within the chemical industry. These reactions frequently employ hazardous solvents; however, to adhere to increasing sustainability pressures and restrictions regarding the use of such solvents, alternatives are highly sought after. Here we demonstrate the utility of dimethyl isosorbide (DMI) as a bio-derived solvent in several benchmark Pd-catalyzed reactions: Suzuki–Miyaura (13 examples, 62–100% yield), Mizoroki–Heck (13 examples, 47–91% yield), and Sonogashira (12 examples, 65–98% yield).
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27
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Atom Efficient Synthesis of Selectively Difluorinated Carbocycles through a Gold(I)-Catalyzed Cyclization. J Org Chem 2018; 83:8888-8905. [PMID: 29978696 DOI: 10.1021/acs.joc.8b01121] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The intramolecular carbocyclization of difluorinated enol acetals has been achieved for the first time using gold(I) catalysis. Difluorinated enol acetals bearing a pendant alkene group can be cyclized and reduced in one pot to form fluorinated diol motifs. Alternatively, the cyclization of terminal alkynes allows for the synthesis of fluorinated pyran scaffolds. Both cyclization processes can be performed under mild conditions allowing access to complex products rich in functionality. The cyclic systems are synthesized concisely (maximum four steps) from trifluoroethanol, an inexpensive fluorinated feedstock.
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28
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Scalable total synthesis and comprehensive structure-activity relationship studies of the phytotoxin coronatine. Nat Commun 2018; 9:1105. [PMID: 29549326 PMCID: PMC5856746 DOI: 10.1038/s41467-018-03443-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Accepted: 02/13/2018] [Indexed: 11/29/2022] Open
Abstract
Natural phytotoxins are valuable starting points for agrochemical design. Acting as a jasmonate agonist, coronatine represents an attractive herbicidal lead with novel mode of action, and has been an important synthetic target for agrochemical development. However, both restricted access to quantities of coronatine and a lack of a suitably scalable and flexible synthetic approach to its constituent natural product components, coronafacic and coronamic acids, has frustrated development of this target. Here, we report gram-scale production of coronafacic acid that allows a comprehensive structure–activity relationship study of this target. Biological assessment of a >120 member library combined with computational studies have revealed the key determinants of potency, rationalising hypotheses held for decades, and allowing future rational design of new herbicidal leads based on this template. Development of comprehensive structure–activity relationships for coronatine has been a major goal in the agrochemical industry. Here, the authors report the gram-scale production and structure–activity relationship of parent coronafacic acid and ultimately rationalise the biological activity of analogues of this phytotoxin.
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29
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Surface Functionalization with Carboxylic Acids by Photochemical Microcontact Printing and Tetrazole Chemistry. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:2132-2138. [PMID: 29334733 DOI: 10.1021/acs.langmuir.7b03678] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In this paper, we show that carboxylic acid-functionalized molecules can be patterned by photochemical microcontact printing on tetrazole-terminated self-assembled monolayers. Upon irradiation, tetrazoles eliminate nitrogen to form highly reactive nitrile imines, which can be ligated with several different nucleophiles, carboxylic acids being the most reactive. As a proof of concept, we immobilized trifluoroacetic acid to monitor the reaction with X-ray photoelectron spectroscopy. Moreover, we also immobilized peptides and fabricated carbohydrate-lectin as well as biotin-streptavidin microarrays using this method. Surface-patterning was demonstrated by fluorescence microscopy and time-of-flight secondary ion mass spectrometry.
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30
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Practical synthesis of pharmaceutically relevant molecules enriched in sp3 character. Chem Commun (Camb) 2018; 54:46-49. [DOI: 10.1039/c7cc08670a] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A highly efficient and general procedure for the preparation of medicinally relevant compounds with enhanced 3D character is reported.
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31
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Abstract
Cyrene was found to be an effective bio-based solvent for HATU mediated amide bond formation.
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32
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Abstract
An organobase-mediated multicomponent reaction of unactivated esters, epoxides, and amines is reported, furnishing functionalized amide derivatives. A wide range of substrates are tolerated under the reaction conditions, including chiral epoxides, which react with no erosion of enantiopurity. Facile modification of the method through replacing the ester derivative with dimethyl carbonate enables access to the corresponding oxazolidinone derivatives.
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Abstract
The Suzuki–Miyaura (SM) cross-coupling is the most broadly utilized Pd-catalyzed C–C bond-forming reaction in the chemical industry. A large proportion of SM couplings employ dipolar aprotic solvents; however, current sustainability initiatives and increasingly stringent regulations advocate the use of alternatives that exhibit more desirable properties. Here we describe the scope and utility of the bio-derived solvent Cyrene™ in SM cross-couplings and evaluate its suitability as a reaction medium for this benchmark transformation from discovery to gram scale.
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One-Pot, Three-Step Synthesis of Cyclopropylboronic Acid Pinacol Esters from Synthetically Tractable Propargylic Silyl Ethers. Org Lett 2017; 19:3891-3894. [DOI: 10.1021/acs.orglett.7b01778] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Rational Design of Autotaxin Inhibitors by Structural Evolution of Endogenous Modulators. J Med Chem 2017; 60:2006-2017. [DOI: 10.1021/acs.jmedchem.6b01743] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Investigation of a Bicyclo[1.1.1]pentane as a Phenyl Replacement within an LpPLA 2 Inhibitor. ACS Med Chem Lett 2017; 8:43-48. [PMID: 28105273 DOI: 10.1021/acsmedchemlett.6b00281] [Citation(s) in RCA: 132] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 11/15/2016] [Indexed: 02/07/2023] Open
Abstract
We describe the incorporation of a bicyclo[1.1.1]pentane moiety within two known LpPLA2 inhibitors to act as bioisosteric phenyl replacements. An efficient synthesis to the target compounds was enabled with a dichlorocarbene insertion into a bicyclo[1.1.0]butane system being the key transformation. Potency, physicochemical, and X-ray crystallographic data were obtained to compare the known inhibitors to their bioisosteric counterparts, which showed the isostere was well tolerated and positively impacted on the physicochemical profile.
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Structure-Activity Relationships of Small Molecule Autotaxin Inhibitors with a Discrete Binding Mode. J Med Chem 2017; 60:722-748. [PMID: 27982588 DOI: 10.1021/acs.jmedchem.6b01597] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Autotaxin (ATX) is a secreted enzyme responsible for the hydrolysis of lysophosphatidylcholine (LPC) to the bioactive lysophosphatidic acid (LPA) and choline. The ATX-LPA signaling pathway is implicated in cell survival, migration, and proliferation; thus, the inhibition of ATX is a recognized therapeutic target for a number of diseases including fibrotic diseases, cancer, and inflammation, among others. Many of the developed synthetic inhibitors for ATX have resembled the lipid chemotype of the native ligand; however, a small number of inhibitors have been described that deviate from this common scaffold. Herein, we report the structure-activity relationships (SAR) of a previously reported small molecule ATX inhibitor. We show through enzyme kinetics studies that analogues of this chemotype are noncompetitive inhibitors, and by using a crystal structure with ATX we confirm the discrete binding mode.
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Abstract
A catalytic amidation protocol mediated by 2,2,2-trifluoroethanol has been developed, facilitating the condensation of unactivated esters and amines, furnishing both secondary and tertiary amides.
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Correction to Evolution of a Novel, Orally Bioavailable Series of PI3Kδ Inhibitors from an Inhaled Lead for the Treatment of Respiratory Disease. J Med Chem 2016; 59:9574. [DOI: 10.1021/acs.jmedchem.6b01461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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41
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Crohn's disease: First diagnosis in pregnancy and management. Obstet Med 2016; 10:85-87. [PMID: 28680469 DOI: 10.1177/1753495x16671231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 08/29/2016] [Indexed: 12/11/2022] Open
Abstract
This case addresses the difficulty in the initial diagnosis of severe Crohn's disease in pregnancy as well as the challenges of instituting remission therapy towards the end of second trimester. The patient's course was complicated by recurrent hospital admissions and intolerance to diet requiring temporary nasogastric feeding. Medical management included the use of biological agents during pregnancy, which allowed for better symptomatic control. She sustained no further complications and underwent a successful vaginal delivery of a healthy baby at 37 weeks' gestation.
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Scope and limitations of a DMF bio-alternative within Sonogashira cross-coupling and Cacchi-type annulation. Beilstein J Org Chem 2016; 12:2005-2011. [PMID: 27829904 PMCID: PMC5082449 DOI: 10.3762/bjoc.12.187] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 08/22/2016] [Indexed: 01/18/2023] Open
Abstract
Pd-catalysed C-C bond formation is an essential tool within the pharmaceutical and agrochemical industries. Many of these reactions rely heavily on polar aprotic solvents; however, despite their utility, these solvents are incompatible with the drive towards more sustainable chemical synthesis. Herein, we describe the scope and limitations of an alternative to DMF derived from renewable sources (CyreneTM) in Sonogashira cross-coupling and Cacchi-type annulations.
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Correction to Evolution of a Novel, Orally Bioavailable Series of PI3Kδ Inhibitors from an Inhaled Lead for the Treatment of Respiratory Disease. J Med Chem 2016; 59:8148. [DOI: 10.1021/acs.jmedchem.6b01157] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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A phase I, open-label, dose-escalation, multicenter study of the JAK2 inhibitor NS-018 in patients with myelofibrosis. Leukemia 2016; 31:393-402. [PMID: 27479177 PMCID: PMC5292677 DOI: 10.1038/leu.2016.215] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 06/24/2016] [Accepted: 07/04/2016] [Indexed: 12/13/2022]
Abstract
NS-018 is a Janus-activated kinase 2 (JAK2)-selective inhibitor, targeting the JAK–signal transducer and activator of transcription (STAT) pathway that is deregulated in myelofibrosis. In this phase I, dose-escalation portion of a phase I/II study, patients with myelofibrosis received oral NS-018 in continuous 28-day cycles. The primary study objective was to evaluate safety, tolerability and clinically active dose of NS-018. Forty-eight patients were treated; 23 (48%) had previously received a JAK inhibitor (JAKi). The most common drug-related adverse events were thrombocytopenia (27%)/anemia (15%) for hematologic events, and dizziness (23%)/nausea (19%) for non-hematologic events. Once daily NS-018 at 300 mg was chosen as the phase II study dose based on improved tolerability compared with higher doses. A ⩾50% reduction in palpable spleen size was achieved in 56% of patients (47% of patients with prior JAKi treatment), and improvements were observed in myelofibrosis-associated symptoms. Bone marrow fibrosis grade (local assessment) improved from baseline in 11/30 evaluable patients (37%) after 3 cycles of NS-018. JAK2 allele burden was largely unchanged. Changes in cytokine/protein levels were noted after 4 weeks of treatment. NS-018 reached peak plasma concentration in 1–2 h and did not accumulate with multiple dosing. NS-018 will be assessed in patients with previous JAKi exposure in the phase II portion.
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Evolution of a Novel, Orally Bioavailable Series of PI3Kδ Inhibitors from an Inhaled Lead for the Treatment of Respiratory Disease. J Med Chem 2016; 59:7239-51. [DOI: 10.1021/acs.jmedchem.6b00799] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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47
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Structurally Diverse Mitochondrial Branched Chain Aminotransferase (BCATm) Leads with Varying Binding Modes Identified by Fragment Screening. J Med Chem 2016; 59:2452-67. [DOI: 10.1021/acs.jmedchem.5b01607] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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48
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Development of Autotaxin Inhibitors: An Overview of the Patent and Primary Literature. J Med Chem 2016; 59:5604-21. [DOI: 10.1021/acs.jmedchem.5b01599] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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49
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Palladium-Catalyzed Synthesis of Aryl Amides through Silanoate-Mediated Hydrolysis of Nitriles. Synlett 2015. [DOI: 10.1055/s-0035-1560724] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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50
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A phase 2 randomized dose-ranging study of the JAK2-selective inhibitor fedratinib (SAR302503) in patients with myelofibrosis. Blood Cancer J 2015; 5:e335. [PMID: 26252788 PMCID: PMC4558588 DOI: 10.1038/bcj.2015.63] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 07/09/2015] [Indexed: 01/15/2023] Open
Abstract
In this phase 2 open-label randomized study, 31 patients with intermediate-2 or high-risk myelofibrosis received fedratinib 300, 400 or 500 mg once daily in consecutive 4-week cycles. Mean spleen volume reductions at 12 weeks (primary end point) were 30.3% (300 mg), 33.1% (400 mg) and 43.3% (500 mg). Spleen response rates (patients achieving ⩾35% spleen reduction) at 12/24 weeks were 30%/30% (300 mg), 50%/60% (400 mg) and 64%/55% (500 mg), respectively. By 4 weeks, improvements in myelofibrosis (MF)-associated symptoms were observed. At 48 weeks, 68% of patients remained on fedratinib and 16% had discontinued because of adverse events (AEs). Common grade 3/4 AEs were anemia (58%), fatigue (13%), diarrhea (13%), vomiting (10%) and nausea (6%). Serious AEs included one case of reversible hepatic failure and one case of Wernicke's encephalopathy (after analysis cutoff). Fedratinib treatment led to reduced STAT3 phosphorylation but no meaningful change in JAK2V617F allele burden. Significant modulation (P<0.05, adjusted for multiple comparisons) of 28 cytokines was observed, many of which correlated with spleen reduction. These data confirm the clinical activity of fedratinib in MF. After the analysis cutoff date, additional reports of Wernicke's encephalopathy in other fedratinib trials led to discontinuation of the sponsored clinical development program.
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