Sc(OTf)₃-Mediated One-Pot Synthesis of Coumarin-Fused Furans: A Thiol-Dependent Reaction for the Easy Access of 2-Phenyl-4H-furo[3,2-c]chromen-4-ones

Abstract

Herein, we report a simple and efficient method for the preparation of novel thioether-linked coumarin-fused furans from the one-pot three-component reaction of arylglyoxal, 4-hydroxycoumarin, and various aromatic thiols in the presence of Sc­(OTf)3 as a catalyst. This methodology is also applicable to cyclic 1,3-dicarbonyls such as cyclohexane-1,3-dione and dimedone. Depending upon the thiols, this methodology can either give a three-component thioether-linked coumarin-fused furan (4) or a two-component furocoumarin product (5). Wide substrate scope, good to excellent yields, and products having more than one pharmaceutically important motif are the salient features of this methodology.

FeCl3-catalyzed regioselective ring-opening of aryl oxirane with 4-hydroxycoumarin for the synthesis of furo[3,2-c]coumarins

“…210–215 °C). 18 1 H NMR (600 MHz, CDCl 3 ) δ 7.95 (d, J = 7.7 Hz, 1H), 7.80 (dd, J = 8.6, 5.2 Hz, 2H), 7.55–7.52 (m, 1H), 7.47 (d, J = 8.3 Hz, 1H), 7.39 (t, J = 7.5 Hz, 1H), 7.18 (t, J = 8.6 Hz, 2H), 7.13 (s, 1H); 13 C NMR (150 MHz, CDCl 3 ) δ 163.3 ( J C–F = 248.7 Hz), 158.3, 157.0, 155.8, 152.7, 130.8, 126.7( J C–F = 8.2 Hz), 125.4 ( J C–F = 3.3 Hz), 124.7, 120.9, 117.6, 116.4 ( J C–F = 22 Hz), 112.8, 112.6, 102.5 ( J C–F = 1.0 Hz); 19 F NMR (565 MHz, CDCl 3 ) δ −110.99; IR (KBr) ν max /cm −1 1750 (CO), 1590 (CC), 1280 (C–O); HRMS (ESI) calcd for C 17 H 10 FO 3 281.0609 (M + H + ); found 281.0609.…”

“…168–170 °C). 18 1 H NMR (400 MHz, CDCl 3 ) δ 7.99 (dd, J = 7.8, 1.4 Hz, 1H), 7.63 (d, J = 8.2 Hz, 2H), 7.56–7.51 (m, 1H), 7.48–7.46 (m, 1H), 7.41–7.35 (m, 2H), 7.22 (d, J = 7.3 Hz, 1H), 7.17 (s, 1H), 2.45 (s, 3H); 13 C NMR (100 MHz, CDCl 3 ) δ 175.1, 152.7, 138.9, 130.7, 130.7, 130.1, 129.1, 129.0, 128.6, 125.3, 124.7, 121.9, 120.9, 117.5, 112.9, 112.6, 102.7, 21.6; IR (KBr) ν max /cm −1 1743 (CO), 1585 (CC), 1200 (C–O); HRMS (ESI) calcd for C 18 H 13 O 3 277.0860 (M + H + ); found 277.0862.…”

“…234 °C). 18 1 H NMR (400 MHz, CDCl 3 ) δ 7.92 (d, J = 2.4 Hz, 1H), 7.82–7.79 (m, 2H), 7.48 (dd, J = 8.9, 2.4 Hz, 1H), 7.41 (d, J = 8.9 Hz, 1H), 7.19 (t, J = 8.7 Hz, 2H), 7.13 (s, 1H). 13 C NMR (100 MHz, CDCl 3 ) δ 163.4 ( J C–F = 249.09 Hz), 157.7, 156.5, 155.6, 151.0, 130.7, 130.3, 126.8 ( J C–F = 8.34 Hz), 125.1 ( J C–F = 3.37 Hz), 120.4, 119.0, 116.5 ( J C–F = 33.12 Hz), 113.8, 113.4, 102.6 ( J C–F = 1.44 Hz).…”