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Donald MB, Rodriguez KX, Shay H, Phuan PW, Verkman AS, Kurth MJ. Click-based synthesis of triazolobithiazole ΔF508-CFTR correctors for cystic fibrosis. Bioorg Med Chem 2012; 20:5247-53. [PMID: 22841006 DOI: 10.1016/j.bmc.2012.06.046] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2012] [Revised: 06/21/2012] [Accepted: 06/27/2012] [Indexed: 11/24/2022]
Abstract
Copper catalyzed azide-alkyne cycloaddition (CuAAC) chemistry is reported for the construction of previously unknown 5-(1H-1,2,3-triazol-1-yl)-4,5'-bithiazoles from 2-bromo-1-(thiazol-5-yl)ethanones. These novel triazolobithiazoles are shown to have cystic fibrosis (CF) corrector activity and, compared to the benchmark bithiazole CF corrector corr-4a, improved logP values (4.5 vs 5.96).
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52
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Ibarra-Soza JM, Morris AA, Jayalath P, Peacock H, Conrad WE, Donald MB, Kurth MJ, Beal PA. 7-Substituted 8-aza-7-deazaadenosines for modification of the siRNA major groove. Org Biomol Chem 2012; 10:6491-7. [PMID: 22766576 DOI: 10.1039/c2ob25647a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Here we describe the synthesis of new 7-substituted 8-aza-7-deazaadenosine ribonucleoside phosphoramidites and their use in generating major groove-modified duplex RNAs. A 7-ethynyl analog leads to further structural diversification of the RNA via post-automated RNA synthesis azide-alkyne cycloaddition reactions. In addition, we report preliminary studies on the effects of eight different purine 7-position modifications on RNA duplex stability and pairing specificity. Finally, the effect on RNAi activity of this type of modification at eight different positions in an siRNA guide strand has been explored. Analogs were identified with large 7-position substituents that maintain adenosine pairing specificity and are well-tolerated at specific positions in an siRNA guide strand.
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53
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Guggenheim KG, Toru H, Kurth MJ. One-pot, two-step cascade synthesis of quinazolinotriazolobenzodiazepines. Org Lett 2012; 14:3732-5. [PMID: 22746550 DOI: 10.1021/ol301592z] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
An operationally simple, one-pot, two-step cascade method has been developed to afford quinazolino[1,2,3]triazolo[1,4]benzodiazepines. This unique, atom-economical transformation engages five reactive centers (amide, aniline, carbonyl, azide, and alkyne) and employs environmentally benign iodine as a catalyst. The method proceeds via sequential quinazolinone-forming condensation and intramolecular azide-alkyne 1,3-dipolar cycloaddition reactions. Substrate scope, multicomponent examples, and mechanistic insights are discussed.
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54
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Coffman KC, Hartley TP, Dallas JL, Kurth MJ. Isoxazolodihydropyridinones: 1,3-dipolar cycloaddition of nitrile oxides onto 2,4-dioxopiperidines. ACS COMBINATORIAL SCIENCE 2012; 14:280-4. [PMID: 22352295 DOI: 10.1021/co200200u] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Practical and efficient methods have been developed for the diversity-oriented synthesis of isoxazolodihydropyridinones via the 1,3-dipolar cycloaddition of nitrile oxides onto 2,4-dioxopiperidines. A select few of these isoxazolodihydropyridinones were further elaborated with triazoles by copper-catalyzed azide-alkyne cycloaddition reactions. A total of 70 compounds and intermediates were synthesized and analyzed for drug likeness. Sixty-four of these novel compounds were submitted to the NIH Molecular Libraries Small Molecule Repository for high-throughput biological screening.
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Davison HR, Solano DM, Phuan PW, Verkman AS, Kurth MJ. Fluorinated ΔF508-CFTR correctors and potentiators for PET imaging. Bioorg Med Chem Lett 2012; 22:1602-5. [PMID: 22281185 PMCID: PMC3274619 DOI: 10.1016/j.bmcl.2011.12.128] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2011] [Revised: 12/23/2011] [Accepted: 12/27/2011] [Indexed: 10/14/2022]
Abstract
(19)F-modified bithiazole correctors and phenylglycine potentiators of the ΔF508-CFTR chloride channel were synthesized and their function assayed in cells expressing human ΔF508-CFTR and a halide-sensitive fluorescent protein. Fluorine was incorporated into each scaffold using prosthetic groups for future biodistribution imaging studies using positron emission tomography (PET). The ΔF508-CFTR corrector and potentiator potencies of the fluorinated analogs were comparable to or better than those of the original compounds.
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56
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Knapp JM, Zhu JS, Wood AB, Kurth MJ. Expedient synthesis of a 72-membered isoxazolino-β-ketoamide library by a 2·3-component reaction. ACS COMBINATORIAL SCIENCE 2012; 14:85-8. [PMID: 22181856 DOI: 10.1021/co200199h] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An efficient 2·3-component reaction (2·3CR; a 2-component reaction followed, in one pot, by a3-component reaction) is presented for the synthesis of isoxazolino-β-ketoamides. This 2·3CR proceeds by (i) a Meldrum's acid-generated acyl ketene, which is trapped by an amine to form a β-ketoamide intermediate in a 2CR followed, in one pot, by (ii) a Mannich reaction followed by elimination of dimethyl amine·HCl to generate an α,β-unsaturated β-ketoamide dipolarophile that reacts in a nitrile oxide 1,3-dipolar cycloaddition reaction. This one-pot 2·3CR process delivers the targeted isoxazolino-β-ketoamide product. A total of 72 compounds are presented, all of which have been submitted to the NIH Molecular Libraries Small Molecule Repository for high-throughput biological screening.
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57
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Knapp JM, Wood AB, Phuan PW, Lodewyk MW, Tantillo DJ, Verkman AS, Kurth MJ. Structure-activity relationships of cyanoquinolines with corrector-potentiator activity in ΔF508 cystic fibrosis transmembrane conductance regulator protein. J Med Chem 2012; 55:1242-51. [PMID: 22214395 DOI: 10.1021/jm201372q] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel. The most common CF-causing mutation, ΔF508-CFTR, produces CFTR loss-of-function by impairing its cellular targeting to the plasma membrane and its chloride channel gating. We recently identified cyanoquinolines with both corrector ("Co", normalizing ΔF508-CFTR targeting) and potentiator ("Po", normalizing ΔF508-CFTR channel gating) activities. Here, we synthesized and characterized 24 targeted cyanoquinoline analogues to elucidate the conformational requirements for corrector and potentiator activities. Compounds with potentiator-only, corrector-only, and dual potentiator-corrector activities were found. Molecular modeling studies (conformational search ⇒ force-field lowest energy assessment ⇒ geometry optimization) suggest that (1) a flexible tether and (2) a relatively short bridge between the cyanoquinoline and arylamide moieties are important cyanoquinoline-based CoPo features. Further, these CoPo's may adopt two distinct π-stacking conformations to elicit corrector and potentiator activities.
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58
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Haddadin MJ, Zerdan RMB, Kurth MJ, Fettinger JC. Efficient Syntheses of the Unknown Quinolino[2,3- c]cinnolines: Synthesis of Neocryptolepines. Org Lett 2011. [DOI: 10.1021/ol2030185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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59
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Lodewyk MW, Kurth MJ, Tantillo DJ. Mechanisms for Formation of Diazocinones, Pyridazines, and Pyrazolines from Tetrazines–Oxyanion-Accelerated Pericyclic Cascades? J Org Chem 2011. [DOI: 10.1021/jo202310c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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60
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Haddadin MJ, El-Khatib M, Shoker TA, Beavers CM, Olmstead MM, Fettinger JC, Farber KM, Kurth MJ. Correction to Quinoxalino[2,3- c]cinnolines and Their 5- N-Oxide: Alkoxylation of Methyl-Substituted Quinoxalino[2,3- c]cinnolines to Acetals and Orthoesters. J Org Chem 2011. [DOI: 10.1021/jo2023153] [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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61
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Davison HR, Taylor S, Drake C, Phuan PW, Derichs N, Yao C, Jones EF, Sutcliffe J, Verkman AS, Kurth MJ. Functional fluorescently labeled bithiazole ΔF508-CFTR corrector imaged in whole body slices in mice. Bioconjug Chem 2011; 22:2593-9. [PMID: 22034937 DOI: 10.1021/bc2004457] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We previously reported the identification and structure-activity analysis of bithiazole-based correctors of defective cellular processing of the cystic fibrosis-causing CFTR mutant, ΔF508-CFTR. Here, we report the synthesis and uptake of a functional, fluorescently labeled bithiazole corrector. Following synthesis and functional analysis of four bithiazole-fluorophore conjugates, we found that 5, a bithazole-based BODIPY conjugate, had low micromolar potency for correction of defective ΔF508-CFTR cellular misprocessing, with comparable efficacy to benchmark corrector corr-4a. Intravenous administration of 5 to mice established its stability in extrahepatic tissues for tens of minutes. By fluorescence imaging of whole-body frozen slices, fluorescent corrector 5 was visualized strongly in gastrointestinal organs, with less in lung and liver. Our results provide proof-of-concept for mapping the biodistribution of a ΔF508-CFTR corrector by fluorophore labeling and fluorescence imaging of whole-body slices.
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62
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Patra D, Malaeb NN, Haddadin MJ, Kurth MJ. Influence of Substituent and Solvent on the Radiative Process of Singlet Excited States of Novel Cyclic Azacyanine Derivatives. J Fluoresc 2011; 22:707-17. [DOI: 10.1007/s10895-011-1006-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2011] [Accepted: 10/18/2011] [Indexed: 11/30/2022]
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63
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Haddadin MJ, El-Khatib M, Shoker TA, Beavers CM, Olmstead MM, Fettinger JC, Farber KM, Kurth MJ. Quinoxalino[2,3-c]cinnolines and their 5-N-oxide: alkoxylation of methyl-substituted quinoxalino[2,3-c]cinnolines to acetals and orthoesters. J Org Chem 2011; 76:8421-7. [PMID: 21905671 DOI: 10.1021/jo201687x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the alkoxylation of methyl-substituted quinoxalino[2,3-c]cinnolines to give acetals and orthoesters in high yields. Routes to the precursors of this alkoxylation reaction as well as other quinoxalino[2,3-c]cinnoline and their 5-oxide derivatives are reported. Most of these quinoxalino[2,3-c]cinnolines were prepared by cyclization of the corresponding 2-amino-3-(2-nitrophenyl)quinoxaline, which, in turn, result from an unusual Beirut reaction from benzofurazan oxides plus 2-nitrobenzylcyanides. Mechanistic explanations for these intriguing reactions are presented.
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64
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Knapp JM, Fettinger JC, Kurth MJ. Multicomponent macrocyclization reactions (MCMRs) employing highly reactive acyl ketene and nitrile oxide intermediates. Org Lett 2011; 13:4732-5. [PMID: 21827181 DOI: 10.1021/ol202024a] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An efficient synthesis of spiro-fused macrolactams by a multicomponent macrocyclization reaction (MCMR) is reported. The use of highly reactive, transient intermediates in this MCMR permits short reaction times, even at high dilution. The methods employed for this MCMR were first developed as a four-component strategy for the synthesis of β-ketoamide isoxazolines and a new macrocyclization reaction is reported.
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65
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Naiyanetr P, Butler JD, Meng L, Pfeiff J, Kenny TP, Guggenheim KG, Reiger R, Lam K, Kurth MJ, Ansari AA, Coppel RL, López-Hoyos M, Gershwin ME, Leung PSC. Electrophile-modified lipoic derivatives of PDC-E2 elicits anti-mitochondrial antibody reactivity. J Autoimmun 2011; 37:209-16. [PMID: 21763105 DOI: 10.1016/j.jaut.2011.06.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 05/24/2011] [Accepted: 06/01/2011] [Indexed: 12/27/2022]
Abstract
Our laboratory has hypothesized that xenobiotic modification of the native lipoyl moiety of the major mitochondrial autoantigen, the E2 subunit of the pyruvate dehydrogenase complex (PDC-E2), may lead to loss of self-tolerance in primary biliary cirrhosis (PBC). This thesis is based on the finding of readily detectable levels of immunoreactivity of PBC sera against extensive panels of protein microarrays containing mimics of the inner lipoyl domain of PDC-E2 and subsequent quantitative structure-activity relationships (QSARs). Importantly, we have demonstrated that murine immunization with one such mimic, 2-octynoic acid coupled to bovine serum albumin (BSA), induces anti-mitochondrial antibodies (AMAs) and cholangitis. Based upon these data, we have focused on covalent modifications of the lipoic acid disulfide ring and subsequent analysis of such xenobiotics coupled to a 15mer of PDC-E2 for immunoreactivity against a broad panel of sera from patients with PBC and controls. Our results demonstrate that AMA-positive PBC sera demonstrate marked reactivity against 6,8-bis(acetylthio)octanoic acid, implying that chemical modification of the lipoyl ring, i.e. disruption of the S-S disulfide, renders lipoic acid to its reduced form that will promote xenobiotic modification. This observation is particularly significant in light of the function of the lipoyl moiety in electron transport of which the catalytic disulfide constantly opens and closes and, thus, raises the intriguing thesis that common electrophilic agents, i.e. acetaminophen or non-steroidal anti-inflammatory drugs (NSAIDs), may lead to xenobiotic modification in genetically susceptible individuals that results in the generation of AMAs and ultimately clinical PBC.
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66
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Guggenheim KG, Butler JD, Painter PP, Lorsbach BA, Tantillo DJ, Kurth MJ. Synthesis of spiro-fused pyrazolidoylisoxazolines. J Org Chem 2011; 76:5803-12. [PMID: 21650164 PMCID: PMC3132818 DOI: 10.1021/jo200924y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Routes to structurally unique spiro-fused pyrazolidoylisoxazolines are reported. These methods start with monosubstituted hydrazines or hydrazides and utilize the nitrile oxide 1,3-dipolar cycloaddition reaction to generate the targeted spiro-fused bis-heterocycles. Molecular shape space diversity analyses were performed on these pyrazolidoylisoxazolines showing that manipulation of the appended R groups significantly changes the molecular shape.
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67
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Snyder DS, Tradtrantip L, Yao C, Kurth MJ, Verkman AS. Potent, metabolically stable benzopyrimido-pyrrolo-oxazine-dione (BPO) CFTR inhibitors for polycystic kidney disease. J Med Chem 2011; 54:5468-77. [PMID: 21707078 DOI: 10.1021/jm200505e] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We previously reported the discovery of pyrimido-pyrrolo-quinoxalinedione (PPQ) inhibitors of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel and showed their efficacy in an organ culture model of polycystic kidney disease (PKD) (J. Med. Chem. 2009, 52, 6447-6455). Here, we report related benzopyrimido-pyrrolo-oxazinedione (BPO) CFTR inhibitors. To establish structure-activity relationships and select lead compound(s) with improved potency, metabolic stability, and aqueous solubility compared to the most potent prior compound 8 (PPQ-102, IC(50) ∼ 90 nM), we synthesized 16 PPQ analogues and 11 BPO analogues. The analogues were efficiently synthesized in 5-6 steps and 11-61% overall yield. Modification of 8 by bromine substitution at the 5-position of the furan ring, replacement of the secondary amine with an ether bridge, and carboxylation, gave 6-(5-bromofuran-2-yl)-7,9-dimethyl-8,10-dioxo-11-phenyl-7,8,9,10-tetrahydro-6H-benzo[b]pyrimido [4',5':3,4]pyrrolo [1,2-d][1,4]oxazine-2-carboxylic acid 42 (BPO-27), which fully inhibited CFTR with IC(50) ∼ 8 nM and, compared to 8, had >10-fold greater metabolic stability and much greater polarity/aqueous solubility. In an embryonic kidney culture model of PKD, 42 prevented cyst growth with IC(50) ∼ 100 nM. Benzopyrimido-pyrrolo-oxazinediones such as 42 are potential development candidates for antisecretory therapy of PKD.
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68
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Phuan PW, Yang B, Knapp JM, Wood AB, Lukacs GL, Kurth MJ, Verkman AS. Cyanoquinolines with independent corrector and potentiator activities restore ΔPhe508-cystic fibrosis transmembrane conductance regulator chloride channel function in cystic fibrosis. Mol Pharmacol 2011; 80:683-93. [PMID: 21730204 DOI: 10.1124/mol.111.073056] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ΔPhe508 mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) protein impairs its folding, stability, and chloride channel gating. Although small molecules that separately correct defective ΔPhe508-CFTR folding/cellular processing ("correctors") or chloride channel gating ("potentiators") have been discovered and are in clinical trials, single compounds with bona fide dual corrector and potentiator activities have not been identified. Here, screening of ∼110,000 small molecules not tested previously revealed a cyanoquinoline class of compounds with independent corrector and potentiator activities (termed CoPo). Analysis of 180 CoPo analogs revealed 6 compounds with dual corrector and potentiator activities and 13 compounds with only potentiator activity. N-(2-((3-Cyano-5,7-dimethylquinolin-2-yl)amino)ethyl)-3-methoxybenzamide (CoPo-22), which was synthesized in six steps in 52% overall yield, had low micromolar EC(50) for ΔPhe508-CFTR corrector and potentiator activities by short-circuit current assay. Maximal corrector and potentiator activities were comparable with those conferred by the bithiazole Corr-4a and the flavone genistein, respectively. CoPo-22 also activated wild-type and G551D CFTR chloride conductance within minutes in a forskolin-dependent manner. Compounds with dual corrector and potentiator activities may be useful for single-drug treatment of cystic fibrosis caused by ΔPhe508 mutation.
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69
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Conrad WE, Fukazawa R, Haddadin MJ, Kurth MJ. The Davis-Beirut reaction: N1,N2-disubstituted-1H-indazolones via 1,6-electrophilic addition to 3-alkoxy-2H-indazoles. Org Lett 2011; 13:3138-41. [PMID: 21612219 DOI: 10.1021/ol2010424] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A variety of electrophiles (anhydrides, acid chlorides, carbonochloridates, sulfonyl chlorides, and alkyl bromides) react with 3-methoxy-2H-indazole (1a), benzoxazin[3,2-b]indazole (1d), and oxazolino[3,2-b]indazole (1e) - substrates available by the Davis-Beirut reaction - to yield a diverse set of N(1),N(2)-disubstituted-1H-indazolones. With certain electrophiles, an AERORC (Addition of the Electrophile, Ring Opening, and Ring Closure) process on indazole 1d results in indazoloindazolone formation. An intriguing aspect of these N(1),N(2)-disubstituted-1H-indazolones is that they are poised for diversification through, for example, azide-alkyne cycloaddition chemistry reported here.
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70
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Meng L, Fettinger JC, Kurth MJ. Ethyl 1-benzyl-1,2,3,3a,4,10b-hexa-hydro-pyrrolo-[2',3':3,4]pyrrolo-[1,2-a]benzimidazole-2-carboxyl-ate. Acta Crystallogr Sect E Struct Rep Online 2011; 67:o1214. [PMID: 21754512 PMCID: PMC3089295 DOI: 10.1107/s1600536811014292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 04/15/2011] [Indexed: 12/04/2022]
Abstract
The title molecule, C22H23N3O2, was obtained via an intramolecular cycloaddition of an azomethine ylide and an alkene tethered by a benzimidazole unit. The benzoimidazole unit is essentially planar, with an r.m.s. deviation of 0.0087 Å from the nine constituent atoms. It has a cis fusion of the two pyrrolidine rings as well as a cis ester appendage. The two pyrrolidine rings rings have envelope conformations. The crystal packing is stabilized by aromatic π–π stacking of parallel benzimidazole ring systems, with a centroid-to-centroid distance of 3.518 (6) Å. Weak intermolecular C—H⋯O contacts may also play a role in the stability of the packing.
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71
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Avila B, Solano DM, Haddadin MJ, Kurth MJ. Facile syntheses of novel benzo-1,3-dioxolo-, benzothiazolo-, pyrido-, and quinolino-fused 5H-benzo[d]-pyrazolo[5,1-b][1,3]-oxazines and 1H-pyrazoles. Org Lett 2011; 13:1060-3. [PMID: 21294577 DOI: 10.1021/ol103108z] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A number of novel benzo-1,3-dioxolo-, benzothiazolo-, pyrido-, and quinolino-fused 5H-benzo[d]pyrazolo[5,1-b][1,3]-oxazines and 1H-pyrazoles were synthesized utilizing an easy and effective N,N-bond forming heterocyclization reaction. In so doing, the substrate scope of this heterocyclization reaction, which starts with o-nitroheterocyclic aldehydes, was expanded to provide several unique heterocyclic compounds for biological screening. This work further demonstrates the versatility of this simple, base-mediated, one-pot heterocyclization method in the construction of novel heterocycles.
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72
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Haddadin MJ, Zerdan RMB, Kurth MJ, Fettinger JC. Efficient Syntheses of the Unknown Quinolino[2,3-c]cinnolines; Synthesis of Neocryptolepines. Org Lett 2010; 12:5502-5. [DOI: 10.1021/ol102376a] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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73
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Butler JD, Conrad WE, Lodewyk MW, Fettinger JC, Tantillo DJ, Kurth MJ. Synthesis of substituted chromanones: an organocatalytic aldol/oxa-Michael reaction. Org Lett 2010; 12:3410-3. [PMID: 20617821 DOI: 10.1021/ol101221c] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A diastereoselective organocatalytic aldol/oxa-Michael reaction has been developed to efficiently deliver medicinally relevant 2,3-ring-substituted chromanones. Development of this synthetic strategy revealed an unexpected kinetic anti-Saytzeff elimination; an origin for the observed selectivity is suggested on the basis of the results of quantum chemical calculations. This unusual kinetic selectivity necessitated an isomerization protocol that in turn led to the discovery of an intriguing Pd-mediated isomerization/intramolecular Friedel-Crafts-type alkylation.
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74
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El-Badri MH, Kurth MJ. Synthesis of thiazolo- and 7,8-dihydrothiazolo[4,5-e]benzoisoxazoles. ACTA ACUST UNITED AC 2010; 11:228-38. [PMID: 19154120 DOI: 10.1021/cc800141s] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The first examples of thiazolo[4,5-e]benzoisoxazoles are obtained from bromination of dihydrobenzo[d]isoxazol-4(5H)-one followed by cyclocondensation with thiourea, in the presence of DDQ. Analogously, cyclocondensation with thioamides provided 7,8-dihydrothiazolo[4,5-e]benzoisoxazoles. A 55-member library of these heterocycles is reported.
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75
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Butler JD, Coffman KC, Ziebart KT, Toney MD, Kurth MJ. Orthogonally Protected Thiazole and Isoxazole Diamino Acids: An Efficient Synthetic Route. Chemistry 2010; 16:9002-5. [DOI: 10.1002/chem.201001492] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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