Novel access to 2-substituted quinolin-4-ones by nickel boride-mediated reductive ring transformation of 5-(2-nitrophenyl)isoxazoles

Lohrer, Bernhard und Bracher, Franz (2019): Novel access to 2-substituted quinolin-4-ones by nickel boride-mediated reductive ring transformation of 5-(2-nitrophenyl)isoxazoles. In: Tetrahedron Letters, Bd. 60, Nr. 51, 151327

Abstract

Reductive ring transformation of 3-substituted 5-(2-nitrophenyl)isoxazoles, readily accessible via 1,3-dipolar cycloaddition of 2-ethinylnitrobenzene with nitrile oxides, opens a novel access to 2-substituted quinolin-4-ones. Nickel boride, generated in situ from nickel chloride and sodium borohydride, allows, via simultaneous reduction of the nitro group and reductive cleavage of the isoxazole ring, the one-step conversion into the target quinolin-4-ones. This protocol tolerates various functional groups, except olefins, and thus is complementary to the reductive ring transformation with iron/acetic acid, which predominantly tolerates olefins. (C) 2019 Elsevier Ltd. All rights reserved.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Chemie und Pharmazie > Department für Pharmazie - Zentrum für Pharmaforschung
• Themengebiete: 500 Naturwissenschaften und Mathematik > 540 Chemie
• ISSN: 0040-4039
• Sprache: Englisch