- DPD-Inspired Discovery of Novel LsrK Kinase Inhibitors: An Opportunity to Fight Antimicrobial Resistance
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Antibiotic resistance is posing a continuous threat to global public health and represents a huge burden for society as a whole. In the past decade, the interference with bacterial quorum sensing (QS) (i.e., cell-cell communication) mechanisms has extensively been investigated as a valid therapeutic approach in the pursuit of a next generation of antimicrobials. (S)-4,5-Dihydroxy-2,3-pentanedione, commonly known as (S)-DPD, a small signaling molecule that modulates QS in both Gram-negative and Gram-positive bacteria, is phosphorylated by LsrK, and the resulting phospho-DPD activates QS. We designed and prepared a small library of DPD derivatives, characterized by five different scaffolds, and evaluated their LsrK inhibition in the context of QS interference. SAR studies highlighted the pyrazole moiety as an essential structural element for LsrK inhibition. Particularly, four compounds were found to be micromolar LsrK inhibitors (IC50 ranging between 100 μM and 500 μM) encouraging further exploration of novel analogues as potential new antimicrobials.
- Stotani, Silvia,Gatta, Viviana,Medarametla, Prasanthi,Padmanaban, Mohan,Karawajczyk, Anna,Giordanetto, Fabrizio,Tammela, P?ivi,Laitinen, Tuomo,Poso, Antti,Tzalis, Dimitros,Collina, Simona
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- Small molecule library synthesis using segmented flow
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Flow chemistry has gained considerable recognition as a simple, efficient, and safe technology for the synthesis of many types of organic and inorganic molecules ranging in scope from large complex natural products to silicon nanoparticles. In this paper
- Thompson, Christina M.,Poole, Jennifer L.,Cross, Jeffrey L.,Akritopoulou-Zanze, Irini,Djuric, Stevan W.
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experimental part
p. 9161 - 9177
(2012/01/03)
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- The preparation of substituted pyrazoles from β,β-dibromo-enones by a tandem condensation/Suzuki-Miyaura cross-coupling process
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Two consecutive tandem processes are described for the regioselective, two-step synthesis of 1,3,5-trisubstituted pyrazoles from α- hydroxyketones. The first, a tandem MnO2-mediated oxidation/Ramirez olefination reaction, provides a facile route to β,β-dibromo-enones. These valuable 1,3-dicarbonyl synthons can then be converted into 1,3,5-trisubstituted pyrazoles via a second tandem hydrazine condensation/Suzuki-Miyaura cross-coupling reaction. Using these procedures, a range of aryl and alkyl α-hydroxyketones have been transformed regioselectively into 1,3,5-trisubstituted pyrazoles. Georg Thieme Verlag Stuttgart.
- Beltrán-Rodil, Sandra,Edwards, Michael G.,Pugh, David S.,Reid, Mark,Taylor, Richard J.K.
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scheme or table
p. 602 - 606
(2010/09/18)
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- Scope and limitations in the regioselective synthesis of 1,3,5-trisubstituted pyrazoles from β-amino enones and hydrazine derivatives. 13C-chemical shift prediction rules for 1,3,5-trisubstituted pyrazoles
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β-amino enones react with hydrazine derivatives to give regioselectively 1,3,5-trisubstituted pyrazoles. The synthetic method only presents limitations when the β-substituent of the enone and the hydrazine substituent are bulky or possess an electron withdrawing character. Comparison of the 13C-NMR spectra of the seventy pyrazoles allowed us to estimate a 13C-chemical shift prediction rule for 1,3,5-trisubstituted pyrazoles, with deviations of less than ± 1 ppm.
- Alberola, Angel,Calvo Bleye, Luis,Gonza?lez-Ortega, Alfonso,Sa?daba, M.Luisa,San?udo, M.Carme
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p. 331 - 352
(2007/10/03)
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- Reactivity of p-Phenyl Substituted β-Enamino Compounds using K-10/ultrasound. I. Synthesis of Pyrazoles and Pyrazolinones
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The reactivity of the β-enamino ketones, 3-amino-l-(p-phenyl-substituted)-2-buten-l-ones la-d and β-enamino esters. Ethyl-3-amino-3-(p-phenyl-substituted)-2-propenoates 5a-d were evaluated by systematic studies of the reactions with hydrazine and methylhydrazine by reactions with solid support K-10/ultrasound and homogeneous media (reflux in ethanol or dichloromethane) yielding pyrazole rings 2a-d, Af-methylpyrazoles 3a-d, 4a-d and N-methylpyrazolinones 6a-c and 7a-c. The regiochemistry of the cyclization showed dependence of the reaction conditions employed as well as the substituent in the aromatic ring.
- Valduga, Claudete J.,Braibante, Hugo S.,Braibante, Mara E.F.
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p. 189 - 192
(2007/10/03)
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- Reactivity of p-phenyl substituted β-enamino compounds using K- 10/ultrasound. I. Synthesis of pyrazoles and pyrazolinones
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The reactivity of the β-enamino ketones, 3-amino-1-(p-phenyl- substituted)-2-buten-1-ones 1a-d and β-enamino esters, ethyl 3-amino-3-(p- phenyl-substituted)-2-propenoates 5a-d was systematically studied when allowed to react with hydrazine and methylhydrazine under solid support K- 10/ultrasound conditions and in homogeneous media (reflux in ethanol or dichloromethane). The products were pyrazoles 2a-d, N-methylpyrazoles 3a-d, 4a-d and N-methylpyrazolinones 6a-c and 7a-c. The regiochemistry of the cyclization reactions showed dependence upon the reaction conditions employed as well as upon the substituent in the aromatic ring.
- Valduga,Braibante,Braibante
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p. 1453 - 1457
(2007/10/03)
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- Pyrrole and Pyrazole Ring Closure in Heterogeneous Media
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Pyrroles and pyrazoles may be conveniently prepared by dispersing primary amines or hydrazines and 1,4- or 1,3-diketones, respectively, on alumina or clay (montmorillonite K 10) without solvent, keeping the mixture at 20 deg C or higher temperatures for 1-26 h, and then eluting the product with dichloromethane.
- Texier-Boullet, F.,Klein, B.,Hamelin, J.
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p. 409 - 411
(2007/10/02)
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- INVESTIGATIO OF THE MECHANISMS OF FORMATION OF HETEROCYCLES BY NMR SPECTROSCOPY. INTERMEDIATES IN THE PRODUCTION OF PYRAZOLES FROM 1,3-DIKETONES AND HYDRAZINES
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The structure of the intermediates formed in the reaction of 1,3-diketones RCOCH2COCH3 (R = Me, Et, t-Bu, Ph, CF3) with hydrazines NH2NHR' (R'= H, Me) in methanol and chloroform was determined by NMR spectroscopy in the normal and flow techniques.When R' = H, the reaction takes place through the formation of dihydroxypyrazolidine and 5-hydroxy-2-pyrazolines; for R'= Me, in addition, intermediate products with ketohydroxyazine and ketoenehydrazone structures were detected.A scheme with their participation is proposed for the formation of the isomeric pyrazoles.A pre-equilibrium between the 1,3-diketone, its hydrazinium salt in the Z,Z configuration, and the anion in the E,Z configuration was detected.The reaction rate of the ketone form of the 1,3-diketone is significantly higher than the reaction rate of the enol.
- Selivanov, S. I.,Bogatkin, R. A.,Ershov, B. A.
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p. 788 - 795
(2007/10/02)
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