BULLETIN OF THE
Article
Regioselective Bismuth-Catalyzed Synthesis of Pyranocoumarins
KOREAN CHEMICAL SOCIETY
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128.5, 127.2, 126.0, 124.1, 122.7, 116.8, 114.5, 107.7,
103.5, 36.8, 20.5; FTIR (ATR): 3026, 1714, 1628, 1454,
1385, 1243, 1009, 752, 696, 666, 459 cm−1; HRMS (EI)
m/z: M+ Calcd. for C25H18O3 366.1256; found 366.1258.
2-(3-Methoxyphenyl)-4-phenylpyrano[3,2-c]chromen-5
(4H)-one (4i). Yield: 23 mg (20%); Rf = 0.2 (EtOAc:Hꢁex-
ane = 1:10); Pale red powder; Melting point: 141–143 C;
1H NMR (400 MHz, CDCl3, 293 K, TMS) δ 8.01 (dd,
J1 = 1.44 Hz, J2 = 7.92 Hz, 1H), 7.59–7.55 (m, 1H), 7.43–
7.21 (m, 10H), 6.97–6.94 (m, 1H), 5.84 (d, J = 4.92 Hz,
1H), 4.71 (d, J = 4.92 Hz, 1H), 3.87 (s, 3H); 13C NMR
(100 MHz, CDCl3) δ 161.5, 159.8, 155.7, 152.7, 146.7,
143.5, 134.92, 132.0, 129.7, 128.6, 128.5, 127.2, 124.2,
122.7, 117.2, 116.0, 114.5, 114.4, 110.7, 104.92, 103.6,
55.4, 36.6; FT-IR (ATR): 3081, 3028, 1712, 1627, 1490,
1392, 1305, 1046, 752, 701, 663, 551, 440 cm−1; HRMS
(EI) m/z: M+ Calcd. for C25H18O4 382.1205; found
382.1205.
2-(3-Chlorophenyl)-4-phenylpyrano[3,2-c]chromen-5
(4H)-one (4j). Yield: 75 mg (65%); Rf = 0.3 (EtOAc:Hꢁex-
ane = 1:10); Pale yellow solid; Melting point: 200–202 C;
1H NMR (400 MHz, CDCl3, 293 K, TMS) δ 8.00 (dd,
J1 = 1.44 Hz, J2 = 7.92 Hz, 1H), 7.71–7.70 (m, 1H), 7.62–
7.56 (m, 2H), 7.41–7.31 (m, 8H), 7.25–7.22 (m, 1H), 5.86
(d, J = 4.92 Hz, 1H), 4.71 (d, J = 4.92 Hz, 1H); 13C NMR
(100 MHz, CDCl3) δ 161.3, 155.6, 152.7, 145.7, 143.2,
134.8, 134.4, 132.1, 129.9, 129.2, 128.7, 128.4, 127.4,
124.8, 124.3, 122.8, 122.6, 116.9, 114.3, 104.9, 103.6,
36.6; FT-IR (ATR): 3083, 3027, 1711, 1628, 1391, 1270,
1022, 759, 747, 680, 549, 421 cm−1; HRMS (EI) m/z: M+
Calcd. for C24H15ClO3 386.0710; found 386.0713.
Hexane = 1:10); Yellow solid; Melting point: 116–118 C;
1H NMR (400 MHz, CDCl3, 293 K, TMS) δ 7.89 (d,
J = 2.32 Hz, 1H), 7.75–7.72 (m, 2H), 7.61 (d, J = 2.36 Hz,
1H), 7.49–7.40 (m, 5H), 7.34–7.29 (m, 2H), 7.25–7.20 (m,
1H), 5.84 (d, J = 4.96 Hz, 1H), 4.71 (d, J = 4.96 Hz, 1H),
1.49 (s, 9H), 1.42 (s, 9H); 13C NMR (100 MHz, CDCl3) δ
161.3, 156.4, 149.6, 147.1, 146.3, 143.8, 137.4, 133.0,
129.2, 128.7, 128.6, 128.5, 127.2, 124.7, 116.7, 114.2,
103.8, 102.9, 36.56, 35.2, 34.9, 31.5, 29.9, 29.7; FT-IR
(ATR): 2964, 1708, 1611, 1364, 1264, 1045, 732, 699,
609, 509 cm−1; HRMS (EI) m/z: M+ Calcd. for C32H32O3
464.2351; found 464.2353.
8-Methoxy-2,4-diphenylpyrano[3,2-c]chromen-5(4H)-
one (4n). Yield: 61 mg (53%); Rf = 0.2 (EtOAc: Hꢁex-
ane = 1:10); Pale yellow solid; Melting point: 205–207 C;
1H NMR (400 MHz, CDCl3, 293 K, TMS) δ 7.89 (d,
J = 8.84 Hz, 1H), 7.72–7.70 (m, 2H), 7.46–7.40 (m, 5H),
7.33–7.29 (m, 2H), 7.25–7.20 (m, 1H), 6.94–6.92 (m, 1H),
6.80 (d, J = 2.36 Hz, 1H), 5.83 (d, J = 4.92 Hz, 1H), 4.66
(d, J = 4.92 Hz, 1H), 3.86 (s, 3H); 13C NMR (100 MHz,
CDCl3) δ 162.9, 161.9, 156.1, 154.5, 146.7, 143.8, 132.7,
129.2, 128.6, 128.5, 128.4, 127.1, 124.6, 123.7, 112.6,
107.7, 103.8, 100.9, 100.5, 55.8, 36.5; FT-IR (ATR): 3074,
3025, 2851, 1711, 1616, 1398, 1254, 1174, 1029, 694,
553, 459 cm−1; HRMS (EI) m/z: M+ Calcd. for C25H18O4
382.1205; found 382.1206.
General Procedure for Furo[3,2-c]coumarins. To a test
tube were added 4-hydroxycoumarin (1, 0.36 mmol), termi-
nal propargyl alcohol (5, 0.3 mmol), and Bi(OTf)3 (10 mol
%) in diglyme (1.5 mL). The resulting mixture was stirred
at 100 C for 3 h. After completion of the reaction, the
mixture was concentrated and directly purified by column
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9-Methyl-2,4-diphenylpyrano[3,2-c]chromen-5(4H)-one
(4k). Yield: 71 mg (65%); Rf = 0.3 (EtOAc: Hex-
chromatography on silica gel using EtOAc:hexane = 1:7.
1
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ane = 1:10); White solid; Melting point: 216–218 C; H
NMR (400 MHz, CDCl3, 293 K, TMS) δ 7.77–7.73 (m,
3H), 7.47–7.30 (m, 8H), 7.25–7.22 (m, 2H), 5.84 (d,
J = 4.96 Hz, 1H), 4.71 (d, J = 4.92 Hz, 1H), 2.50 (s, 3H);
13C NMR (100 MHz, CDCl3) δ 161.7, 155.8, 151.0, 146.9,
143.7, 134.92, 133.1, 132.7, 129.3, 128.9, 128.7, 128.5,
127.2, 124.7, 122.3, 116.6, 114.2, 103.8, 103.6, 103.4,
36.6, 21.1.6c
1,3-Diphenylbenzo[h]pyrano[3,2-c]chromen-12(1H)-one
(4o). Yield: 36 mg (30%); Rf = 0.3 (EtOAc: Hꢁex-
ane = 1:10); Yellow powder; Melting point: 222–224 C;
1H NMR (400 MHz, CDCl3, 293 K, TMS) δ 8.51–8.49 (m,
1H), 8.00 (d, J = 8.72 Hz, 1H), 7.91–7.88 (m, 1H), 7.78–
7.76 (m, 3H), 7.64–7.61 (m, 2H), 7.49–7.42 (m, 5H), 7.34–
7.31 (m, 2H), 7.25–7.23 (m, 1H), 5.88 (d, J = 4.92 Hz,
1H), 4.76 (d, J = 4.92 Hz, 1H); 13C NMR (100 MHz,
CDCl3) δ 161.9, 157.1, 150.6, 147.4, 144.1, 135.3, 133.2,
129.7, 129.5, 129.4, 129.2, 128.7, 128.3, 127.7, 127.6,
125.2, 124.7, 123.4, 123.0, 118.7, 110.2, 104.2, 103.6,
37.1; FT-IR (ATR): 3058, 3024, 2921, 1710, 1617, 1376,
1021, 811, 756, 695, 567, 422 cm−1; HRMS (EI) m/z: M+
Calcd. for C28H18O3 402.1256; found 402.1254.
7-Methyl-2,4-diphenylpyrano[3,2-c]chromen-5(4H)-one
(4l). Yield: 79 mg (72%); Rf = 0.3 (EtOAc: Hexane = 1:10);
Yellow powder; Melting point: 162–163 ꢁC; 1H NMR
(400 MHz, CDCl3, 293 K, TMS) δ 7.86 (dd, J1 = 1.0 Hz,
J2 = 7.92 Hz, 1H),), 7.74–7.71 (m, 2H), 7.46–7.37 (m, 6H),
7.34–7.19 (m, 4H), 5.84 (d, J = 4.92 Hz, 1H), 4.71 (d,
J = 4.96 Hz, 1H), 2.42 (s, 3H); 13C NMR (100 MHz,
CDCl3) δ 162.6, 161.5, 155.9, 151.1, 147.0, 143.7, 133.2,
132.7, 129.2, 128.7, 128.6, 128.5, 127.2, 126.3, 124.7,
123.7, 120.3, 114.3, 103.7, 103.4, 36.6, 15.7; FT-IR
(ATR): 3062, 3026, 1713, 1630, 1467, 1386, 1216, 1012,
757, 701, 606, 548, 447 cm−1; HRMS (EI) m/z: M+ Calcd.
for C25H18O3 366.1256; found 366.1254.
2-Methyl-3-phenyl-4H-furo[3,2-c]chromen-4-one
(6a).
Yield: 59 mg (71%); Rf = 0.3 (EtOAc:Hexane = 1:7); Pale
yellow powder; Melting point: 195–197 ꢁC; 1H NMR
(400 MHz, CDCl3, 293 K, TMS)
δ 7.84 (dd, 1H,
J1 = 1.36 Hz, J2 = 7.8 Hz), 7.52–7.30 (m, 8H), 2.51 (s,
3H); 13C NMR (100 MHz, CDCl3) δ 157.7, 156.3, 152.3,
151.7, 130.3, 130.0, 129.9, 128.2, 127.8, 124.3, 120.6,
120.5, 117.1, 112.8, 109.6, 12.6; FTIR (ATR): 3069, 2918,
7,9-Di-tert-butyl-2,4-diphenylpyrano[3,2-c]chromen-5
(4H)-one (4m). Yield: 67 mg (48%); Rf = 0.6 (EtOAc:
Bull. Korean Chem. Soc. 2020, Vol. 41, 709–718
© 2020 Korean Chemical Society, Seoul & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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