2505-98-8Relevant academic research and scientific papers
Non-Decarboxylative Ruthenium-Catalyzed Rearrangement of 4-Alkylidene-isoxazol-5-ones to Pyrazole- and Isoxazole-4-carboxylic Acids
Loro, Camilla,Molteni, Letizia,Papis, Marta,Lo Presti, Leonardo,Foschi, Francesca,Beccalli, Egle M.,Broggini, Gianluigi
, p. 3092 - 3096 (2022/05/02)
Treatment of 4-(2-hydroaminoalkylidenyl)- and 4-(2-hydroxyalkylidenyl)-substituted isoxazol-5(4H)-ones with catalytic amounts of [RuCl2(p-cymene)]2, without any additive, afforded pyrazole- and isoxazole-4-carboxylic acids, respectively. The presence of an intramolecular H-bond in these substrates was the key to divert the classical mechanism toward a ring-opening non-decarboxylative path that is expected to generate a vinyl Ru-nitrenoid intermediate, the cyclization of which affords the rearranged products. A gram scale protocol demonstrated the synthetic applicability of this transformation.
Synthesis, pharmacological characterization, and docking analysis of a novel family of diarylisoxazoles as highly selective cyclooxygenase-1 (COX-1) inhibitors
Vitale, Paola,Tacconelli, Stefania,Perrone, Maria Grazia,Malerba, Paola,Simone, Laura,Scilimati, Antonio,Lavecchia, Antonio,Dovizio, Melania,Marcantoni, Emanuela,Bruno, Annalisa,Patrignani, Paola
, p. 4277 - 4299 (2013/07/19)
3-(5-Chlorofuran-2-yl)-5-methyl-4-phenylisoxazole (P6), a known selective cyclooxygenase-1 (COX-1) inhibitor, was used to design a new series of 3,4-diarylisoxazoles in order to improve its biochemical COX-1 selectivity and antiplatelet efficacy. Structure-activity relationships were studied using human whole blood assays for COX-1 and COX-2 inhibition in vitro, and results showed that the simultaneous presence of 5-methyl (or -CF3), 4-phenyl, and 5-chloro(-bromo or -methyl)furan-2-yl groups on the isoxazole core was essential for their selectivity toward COX-1. 3g, 3s, 3d were potent and selective COX-1 inhibitors that affected platelet aggregation in vitro through the inhibition of COX-1-dependent thromboxane (TX) A2. Moreover, we characterized their kinetics of COX-1 inhibition. 3g, 3s, and 3d were more potent inhibitors of platelet COX-1 and aggregation than P6 (named 6) for their tighter binding to the enzyme. The pharmacological results were supported by docking simulations. The oral administration of 3d to mice translated into preferential inhibition of platelet-derived TXA2 over protective vascular-derived prostacyclin (PGI2).
Boronic acid catalysis for mild and selective [3+2] dipolar cycloadditions to unsaturated carboxylic acids
Zheng, Hongchao,McDonald, Robert,Hall, Dennis G.
experimental part, p. 5454 - 5460 (2010/09/15)
Herein, the concept of boronic acid catalysis (BAC) for the activation of unsaturated carboxylic acids is applied in several classic dipolar [3 + 2] cycloadditions involving azides, nitrile oxides, and nitrones as partners. These cycloadditions can be used to produce pharmaceutically interesting, small heterocyclic products, such as triazoles, isoxazoles, and isoxazolidines. These cycloadducts are formed directly and include a free carboxylic acid functionality that can be employed for fur-ther transformations, thereby avoiding prior masking or functionalization. In all cases, BAC provides faster reactions, under milder conditions, with much improved product yields and regioselectivities. In some instances, such as triazole formation from the reaction of azides with 2-alkynoic acids, catalysis with ort/io- nitrophenylboronic acid circumvents the undesirable product decarboxylation observed when using thermal activation. By using NMR spectroscopic studies, the boronic acid catalyst was shown to provide activation by a LUMO-lowering effect in the unsaturated carboxylic acid, likely via a monoacylated hemiboronic ester intermediate.
Functionalized diarylisoxazoles inhibitors of ciclooxygenase
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Page/Page column 13-14, (2009/07/25)
The present invention refers to isoxazole derivatives, in particular diarylisoxazole derivatives inhibitors of cyclooxygenase (COX), in particular cyclooxygenase-1 (COX-1), to their pharmaceutical compositions, the process for their preparation and their use for the chemoprevention and treatment of inflammatory syndromes and in the prevention and treatment of carcinomas, in particular intestinal, ovarian and cutaneous carcinomas, in the treatment of pain syndromes, in particular after surgery, and in the cardiovascular field as antithrombotics/vasoprotectives/cardioprotectives.
Regioselectivity in cycloaddition reactions on solid phases
Yedidia, Varda,Leznoff, Clifford C.
, p. 1144 - 1150 (2007/10/02)
A 1percent crosslinked divinylbenzene-styrene copolymer, incorporating benzyl acrylate groups, reacted in normal Diels-Alder reactions with E-1-phenyl-1,3-butadiene or methyl E-2,4-pentadienoate to give their respective polymer-bound benzyl cyclohexenecarboxylates.Polymer-bound benzyl propiolate and polymer-bound benzyl phenylpropiolate reacted with benzonitrile oxide in a typical 1,3-dipolar addition reaction to give their respective polymer-bound isoxazoles.Cleavage of the polymer-bound Diels-Alder adducts and the polymer-bound 1,3-dipolar addition adduct derived from polymer-bound benzyl propiolate gave mixtures of ortho and meta regiomers similar to those produced in analogous reactions in solution.Cleavage of the polymer-bound 1,3-dipolar addition adduct, derived from polymer-bound benzyl phenylpropiolate, followed by esterification, gave a solitary adduct, 4-carbomethoxy-3,5-diphenylisoxazole, but an analogous solution 1,3-dipolar addition yielded a 1:1 ratio of the two possible regiomers.
