The Journal of Organic Chemistry
Page 8 of 10
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65%). mp = 181-183 oC. 1H NMR (300 MHz, CDCl3): δ = 8.01
(d, J = 8.61, 1H), 7.53 (s, 1H), 7.67 (d, J = 8.0 Hz, 1H), 4.96
(d, J = 2.8Hz, 1H), 4.73 (d, J = 2.7Hz, 1H), 3.93 (s, 3H), 2.35-
188-190 C. H NMR (300 MHz, DMSO-d6): δ = 7.88 (d, J =
7.9, 1H), 7.79 (s, 1H), 7.72-7.16 (m, 2H), 5.01 (d, J = 2.8Hz,
1H), 4.84 (d, J = 3.0Hz, 1H), 2.45 (s, 3H), 2.19-2.15 (m, 2H),
1.67 (s, 7H), 1.39-1.35 (m, 1H) ppm. 13C NMR (75 MHz,
CDCl3): δ = 181.1, 177.4, 167.6, 156.2, 144.0, 134.8, 131.9,
130.98, 130.90, 126.6, 126.4, 91.1, 48.9, 33.6, 24.4, 21.6, 20.0
ppm. IR (KBr): 3116, 2933, 2868, 1741, 1681, 1664, 1647, 1627,
1600, 1469, 1367, 1278, 1224, 1190, 1157, 1039, 1029, 900, 862,
738, 690 cm-1. HRMS (APCI+): calcd for C19H19O3 (M+H)+
295.1329, found 295.1338.
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2.26 (m, 2H), 1.73-1.71 (m, 7H), 1.28-1.25 (m, 1H) ppm. C
NMR (75 MHz, CDCl3): δ = 180.6, 177.2, 167.6, 163.5, 156.1,
132.9, 131.0, 128.5, 126.6, 120.1, 110.0, 91.0, 55.9, 49.0, 33.6,
24.4, 20.0 ppm. IR (KBr): 3118, 2939, 2868, 1805, 1764, 1687,
1681, 1666, 1643, 1624, 1597, 1446, 1288, 1232, 1155, 1014, 891,
867, 846, 744, 694, 603, cm-1. HRMS (APCI+): calcd for
C19H19O4 (M+H)+ 311.1278, found 311.1294.
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7-Bromo-3-ethyl-3-methyl-2-methylene-2,3-dihydronaphtho
(2,3-b)furan-4,9-dione (1o). Purified by column chromatog-
raphy on silica gel (petroleum ether/ethyl acetate = 25/1)
to afford 1o as an orange solid (235.7 mg, 71 %). mp = 213-
7-Hrdroxyl-3-ethyl-3-methyl-2-methylene-2,3-
dihydronaphtho(2,3-b)furan-4,9-dione (1s). Purified by col-
umn chromatography on silica gel (petroleum ether/ethyl
acetate = 10/1) to afford 1s as an orange solid (212.5 mg,
79%). mp = 224-226 oC. 1H NMR (300 MHz, DMSO-d6): δ =
11.03 (s, 1H), 7.84 (d, J = 8.4 Hz, 1H), 7.29 (s, 1H), 7.14 (d, J =
8.6 Hz, 1H), 4.94 (d, J = 2.8 Hz, 1H), 4.59 (d, J = 3.0 Hz,
1H), 2.14-2.07 (m, 1H), 1.64-1.60 (m, 1H), 1.48 (s, 3H), 0.72
(t, J = 7.29 Hz, 3H) ppm. 13C NMR (75 MHz, DMSO-d6): δ =
181.0, 177.1, 167.9, 160.8, 156.7, 133.2, 129.8, 129.0, 126.1, 120.9,
113.1, 87.7, 50.7, 33.2, 27.7, 9.7 ppm. IR (KBr): 3358, 2975,
2930, 1680, 1666, 1644, 1624, 1595, 1444, 1365, 1340, 1252,
1077, 957, 890, 745 cm-1. HRMS (ESI-): calcd for C16H13O4
(M-H)- 269.0819, found 269.0820.
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215 C. H NMR (300 MHz, DMSO-d6): δ = 8.09 (s, 1H),
8.07 (s, 1H), 7.90 (d, J = 8.8 Hz, 1H), 5.00 (d, J = 2.7 Hz,
1H), 4.64 (d, J = 3.1 Hz, 1H), 2.13-2.07 (m, 1H), 1.68-1.63 (m,
1H), 1.50 (s, 3H), 0.72 (t, J = 7.3 Hz, 3H) ppm. 13C NMR (75
MHz, CDCl3): δ = 180.3, 175.7, 167.7, 156.5, 137.1, 132.3, 131.6,
130.0, 129.3, 128.5, 127.9, 88.0, 50.6, 33.3, 27.6, 9.7 ppm. IR
(KBr): 3116, 2981, 2942, 1745, 1670, 1647, 1624, 1597, 1448,
1379, 1363, 1205, 1188, 1132, 1053, 993, 877, 854, 740 cm-1.
HRMS (APCI-): calcd for C16H13BrO3 (M)- 334.0033, found
334.0038.
7-Chloro-3-ethyl-3-methyl-2-methylene-2,3-dihydronaphtho
(2,3-b)furan-4,9-dione (1p). Purified by column chromatog-
raphy on silica gel (petroleum ether/ethyl acetate = 25/1)
to afford 1p as an orange solid (221.8 mg, 77%). mp = 201-
6-Hrdroxyl-3-ethyl-3-methyl-2-methylene-2,3-
dihydronaphtho(2,3-b)furan-4,9-dione (1t). Purified by col-
umn chromatography on silica gel (petroleum ether/ethyl
acetate = 10/1) to afford 1t as an orange solid (217.9 mg,
81%). mp = 227-229 oC. 1H NMR (300 MHz, DMSO-d6): δ =
11.34 (s, 1H), 7.88 (d, J = 8.4 Hz, 1H), 7.33 (s, 1H), 7.16 (d, J =
8.3 Hz, 1H), 4.97 (d, J = 2.9 Hz, 1H), 4.61 (d, J = 2.8 Hz, 1H),
2.12-2.05 (m, 1H), 1.65-1.58 (m, 1H), 1.48 (s, 3H), 0.72 (t, J =
7.14 Hz, 3H) ppm. 13C NMR (75 MHz, DMSO-d6): δ = 181.3,
175.4, 167.9, 162.8, 157.3, 135.4, 129.2, 128.2, 122.9, 120.1, 113.1,
88.0, 50.3, 32.7, 27.5, 9.9 ppm. IR (KBr): 3360, 2931, 2926,
2854, 1678, 1665, 1649, 1622, 1589, 1460, 1396, 1352, 1346,
1209, 1008, 939, 846, 746 cm-1. HRMS (ESI-): calcd for
C16H13O4 (M-H)- 269.0819, found 269.0823.
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203 C. H NMR (300 MHz, DMSO-d6): δ = 7.96-8.04 (m,
3H), 5.05 (d, J = 2.8 Hz, 1H), 4.69 (d, J = 2.7 Hz, 1H), 2.21-
2.10 (m, 1H), 1.75-1.68 (m, 1H), 1.55 (s, 3H), 0.77 (t, J = 7.3
Hz, 3H) ppm. 13C NMR (75 MHz, DMSO-d6): δ = 180.4,
175.4, 167.7, 157.1, 139.0, 134.4, 133.2, 131.5, 129.1, 128.2, 125.7,
88.2, 50.5, 32.8, 27.4, 9.9 ppm. IR (KBr): 3118, 2970, 2958,
1671, 1654, 1625, 1585, 1454, 1384, 1361, 1273, 1207, 1039, 1004,
883, 876, 852, 715, 693 cm-1. HRMS (APCI-): calcd for
C16H13ClO3 (M)- 288.0559, found 288.0558.
3-Ethyl-3,7-dimethyl-2-methylene-2,3-dihydronaphtho(2,3-
b)furan-4,9-dione (1q). Purified by column chromatography
on silica gel (petroleum ether/ethyl acetate = 25/1) to af-
ford 1q as an orange solid (204.4 mg, 76%). mp = 163-165
6'-Hydroxyl-2'-methylene-2'H-spiro(cyclohexane-1,3'-
naphtho(2,3-b)furan)-4',9'-dione (1u). Purified by column
chromatography on silica gel (petroleum ether/ethyl ace-
tate = 10/1) to afford 1u as an orange solid (212.1 mg, 72%).
mp = 286-288 oC. 1H NMR (300 MHz, DMSO-d6): δ = 11.06
(s, 1H), 7.87 (d, J = 8.4 Hz, 1H), 7.31 (s, 1H), 7.10 (d, J = 6.6
Hz, 1H), 4.95 (s, 1H), 4.84 (s, 1H), 2.14 (s, 2H), 1.65 (s, 7H),
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oC. H NMR (300 MHz, DMSO-d6): δ = 7.88 (d, J = 7.8 Hz,
1H), 7.82 (s, 1H), 7.68 (d, J = 7.8 Hz, 1H), 4.97 (d, J = 3.2 Hz,
1H), 4.62 (d, J = 3.2 Hz, 1H), 2.46 (s, 3H), 2.14-2.07 (m, 1H),
1.66-1.60 (m, 1H), 1.50 (s, 3H), 0.71 (t, J = 7.3 Hz, 3H) ppm. -
13C NMR (75 MHz, CDCl3): δ = 181.2, 177.1, 168.0, 156.6,
144.2, 134.8, 131.1, 130.7, 129.5, 126.8, 126.3, 50.6, 33.3, 27.6,
21.6, 9.6 ppm. IR (KBr): 3115, 2972, 2873, 1670, 1647, 1624,
1598, 1448, 1379, 1363, 1157, 1053, 1029, 993, 910, 877, 854,
740 cm-1. HRMS (APCI+): calcd for C17H17O3 (M+H)+
269.1172, found 269.1177.
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1.41-1.33 (m, 1H) ppm. C NMR (75 MHz, DMSO-d6): δ =
181.0, 175.6, 167.6, 163.9, 156.9, 135.8, 129.6, 129.1, 123.1, 119.8,
112.9, 91.3, 48.6, 33.6, 24.7, 20.0 ppm. IR (KBr): 3350, 3118,
2935, 2845, 1664, 1583, 1566, 1446, 1334, 1251, 1186, 1161, 1026,
1060, 954, 896, 842, 746, 638 cm-1. HRMS (ESI-): calcd for
C18H15O4 (M-H)- 295.0976, found 295.0986.
7'-Methyl-2'-methylene-2'H-spiro(cyclohexane-1,3'-naphtho
(2,3-b)furan)-4',9'-dione (1r). Purified by column chroma-
tography on silica gel (petroleum ether/ethyl acetate =
25/1) to afford 1r as an orange solid (162.2 mg, 55%). mp =
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