A General Approach to the Synthesis of Substituted Isoxazolo[4,3‐c]quinolines via Chalcones

Abstract

A general and practical approach to the synthesis of substituted isoxazolo [4,3-c]quinolines from the substituted isoxazolines obtained by 1,3-dipolar cycloadditions between 2-nitrobenzonitrile oxide and chalcones is described. SnCl 2 ·2H 2 O-mediated reduction of the nitro group, followed by intramolecular cyclization involving the amino and the keto groups in these substrates, furnished mixtures of

Nitrile Oxide, Alkenes, Dipolar Cycloaddition, Isomerization and Metathesis Involved in the Syntheses of 2-Isoxazolines

“…In 2007, Madapa and colleagues reported the creation of 3,4,5-trisubstituted isoxazolines on the way to substituted isoxazolo [4,3-c]quinolines— Scheme 176 [ 189 ].…”

“… Syntheses of 3,4,5-trisubstituted 2-isoxazolines in the 1,3-DP cycloaddition between 2-nitrobenzonitrile oxide and aryl-styryl ketones—a crucial step in the synthetic route leading to the quinoline derivatives [ 189 ]. R 1 = p -Cl, p -Br, 2,3-Cl 2 , 2,4-Cl 2 , 3,4-Cl 2 ; R 2 = H or Me.…”

Sequential Addition and Cyclization Processes of α,β-Ynones and α,β-Ynoates Containing Proximate Nucleophiles

“…The synthetic and medicinal importance of isoxazoleannulated ring systems provided enough incentive to devise simple strategies for the generation of these molecu- lar frameworks. 60 A number of isoxazoloquinolines have been identified as MRP1 inhibitors 61 and a class of isoxazoloquinoline derivatives showed anxiolytic activity. 62 For getting through the bottleneck for further studies and developments in medicinal chemistry, the reactivity of β-(2-aminophenyl)-α,β-ynones 1 towards nitrile oxides derived from differently substituted aldehydes was investigated, and provided a clean, mild, and general synthesis of functionalized isoxazolo[4,5-c]quinolines.…”

Silver-Catalyzed Double-Decarboxylative Cross-Coupling of α-Keto Acids with Cinnamic Acids in Water: A Strategy for the Preparation of Chalcones

“…1 H NMR (CDCl 3 , 400 MHz, ppm) δ 7.84 (d, 2H, J = 8 Hz), 7.65 (d, 1H, J = 16 Hz), 7.34 (d, 2H, J = 8 Hz), 7.32−7.29 (m, 3H), 6.85 (d, 1H, J = 16 Hz), 2.46 (s, 3H), 2.37 (s, 3H). 13 (E)-3-(4-Chlorophenyl)-1-p-tolylprop-2-en-1-one (3o): 31 Following the general procedure, the product was isolated in 66% yield (79.4 mg). Eluent petroleum ether/ethyl acetate (20:1).…”