PAPER
One-Pot Synthesis of Aurones
2223
1H NMR (400 MHz, CDCl3): δ = 7.86 (d, J = 8.8 Hz, 2 H), 7.10 (d,
J = 8.8 Hz, 2 H), 6.75 (s, 1 H), 6.64 (s, 1 H), 5.38 (s, 2 H), 5.32–5.29
(m, 3 H), 5.24 (s, 2 H), 3.54 (s, 3 H), 3.52 (s, 3 H), 3.51 (s, 3 H), 3.47
(d, J = 7.2 Hz, 2 H), 1.87 (s, 3 H), 1.71 (s, 3 H).
13C NMR (100 MHz, CDCl3): δ = 181.3, 165.1, 162.9, 158.0, 155.0,
147.0, 132.8, 132.2, 126.5, 121.6, 116.4, 110.6, 108.3, 106.4, 96.3,
95.3, 94.5, 94.2, 56.7, 56.5, 56.2, 25.8, 21.9, 17.9.
13C NMR (100 MHz, CDCl3): δ = 190.9, 160.5, 155.5, 146.4, 136.7,
132.8, 132.7, 132.3, 126.5, 122.2, 121.5, 121.2, 115.4, 114.1, 113.7,
55.3.
MS (EI): m/z (%) = 320 (100) [M+], 322 (73), 324 (15).
Aureusidin [(2Z)-2-(3,4-dihydroxybenzylidene)-4,6-dihydroxy-
1-benzofuran-3(2H)-one]
10% aq HCl (5 mL) was added dropwise to a mixture of benzofura-
none 3h (463 mg, 1 mmol) and MeOH (20 mL) and the resulting
mixture was refluxed for 30 min. Evaporation of the solvent gave a
yellow precipitate that was filtered off and washed successively
with H2O and CH2Cl2; yield: 80% (230 mg).
HRMS-FAB: m/z [M + H]+ calcd for C26H31O8: 471.2013; found:
471.2023.
(2Z)-2-[3,4-Bis(methoxymethoxy)benzylidene]-4,6-bis(meth-
oxymethoxy)-1-benzofuran-3(2H)-one (3h)
Prepared by the general procedure from 1d and 2c as a yellowish
solid; yield: 305 mg (66%); mp 86–88 °C.
1H NMR (400 MHz, CDCl3): δ = 7.69 (s, 1 H), 7.54 (d, J = 8.8 Hz,
1 H), 7.21 (d, J = 8.8 Hz, 1 H), 6.72 (s, 1 H), 6.60 (s, 1 H), 6.52 (s,
1 H), 5.37 (s, 2 H), 5.29 (s, 4 H), 5.26 (s, 2 H), 3.56 (s, 3 H), 3.54 (s,
3 H), 3.53 (s, 3 H), 3.52 (s, 3 H).
1H NMR (400 MHz, CD3OD): δ = 7.47 (d, J = 2.0 Hz, 1 H), 7.18
(dd, J = 8.4, 2.0 Hz, 1 H), 6.82 (d, J = 8.4 Hz, 1 H), 6.56 (s, 1 H),
6.20 (d, J = 1.6 Hz, 1 H), 6.02 (d, J = 1.6 Hz, 1 H).
13C NMR (100 MHz, CD3OD): δ = 183.0, 169.7, 169.5, 160.0,
149.0, 148.0, 146.7, 126.1, 125.9, 118.8, 116.7, 113.0, 104.8, 98.7,
91.8.
13C NMR (100 MHz, CDCl3): δ = 180.6, 168.3, 166.0, 156.8, 148.6,
147.1, 147.0, 126.9, 126.4, 119.6, 116.3, 111.0, 106.6, 98.7, 95.7,
95.1, 95.0, 94.5, 92.9, 56.7, 56.5, 56.3, 56.3.
HRMS-FAB: m/z [M + H]+ calcd for C15H11O6: 287.0550; found:
287.0544.
HRMS-FAB: m/z [M + H]+ calcd for C23H27O10: 463.1599; found:
463.1590.
Acknowledgment
This work was financially supported by the National Natural Sci-
ence Foundation of China (Grant Nos. 20872053 and 21072084).
We also thank Dr Wei Yu of Lanzhou University for helpful discus-
sions.
(2Z)-2-(4-Chlorobenzylidene)-4,6-dimethoxy-1-benzofuran-
3(2H)-one (3i)
Prepared by the general procedure from 1a and 2d as a yellowish
solid; yield: 196 mg (62%); mp 169–171 °C.
1H NMR (400 MHz, CDCl3): δ = 7.75 (d, J = 8.4 Hz, 2 H), 7.54 (d,
J = 8.4 Hz, 2 H), 6.67 (d, J = 7.2 Hz, 1 H), 6.36 (d, J = 3.6 Hz, 1 H),
6.11 (d, J = 3.6 Hz, 1 H), 3.93 (s, 3 H), 3.90 (s, 3 H).
Supporting Information for this article is available online at
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13C NMR (100 MHz, CDCl3): δ = 180.3, 169.0, 168.9, 159.3, 147.9,
135.0, 132.1, 131.0, 128.9, 109.1, 104.9, 94.0, 89.2, 56.1, 56.0.
HRMS-FAB: m/z [M + H]+ calcd for C17H14ClO4: 317.0575; found:
References
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K. R., Eds.; CRC Press: Boca Raton, 2006.
317.0568.
(2Z)-2-(4-Fluorobenzylidene)-4,6-dimethoxy-1-benzofuran-
3(2H)-one (3j)
Prepared by the general procedure from 1a and 2e as a yellowish
solid; yield: 189 mg (63%); mp 174 °C.
1H NMR (400 MHz, CDCl3): δ = 7.83 (m, 2 H), 7.10 (m, 2 H), 6.70
(s, 1 H), 6.36 (s, 1 H), 6.11 (s, 1 H), 3.94 (s, 3 H), 3.90 (s, 3 H).
(2) Boumendjel, A. Curr. Med. Chem. 2003, 10, 2621.
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T.; Reutrakul, V.; Seo, E.-K.; Farnsworth, N. R.; Kinghorn,
A. D. J. Nat. Prod. 1998, 61, 446.
13C NMR (100 MHz, CDCl3): δ = 180.5, 169.0, 168.9, 164.3, 161.8,
159.4, 147.5, 147.4, 133.0, 132.9, 128.8, 128.7, 116.0, 115.7, 109.5,
105.1, 94.0, 89.2, 56.1, 56.0.
HRMS-FAB: m/z [M + H]+ calcd for C17H14FO4: 301.0871; found:
301.0874.
(5) Júnior, G. M. V.; Sousa, C. M. M.; Cavalheiro, A. J.; Lago,
J. H. G.; Chaves, M. H. Helv. Chim. Acta 2008, 91, 2159.
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Seeber, E.; Meijer, L.; Lozach, O.; Vangrevelinghe, E.;
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(2Z)-4,6-Dichloro-2-(4-methoxybenzylidene)-1-benzofuran-
3(2H)-one (3g)
Dichloro ketone 1g (204 mg, 1 mmol) was added to a soln of NaOH
(0.64 g) in EtOH (9.6 mL) at r.t. and the mixture was stirred for 5
min. Aldehyde 2a (143 mg, 1.05 mmol) was then added and the
mixture was stirred for 24 h. H2O (9.6 mL) was added, followed by
30% H2O2 (0.272 mL) added dropwise over 5 min. The mixture was
stirred for another 24 h then extracted with EtOAc (3 × 20 mL). The
organic layer was washed successively with 1 M HCl (20 mL), H2O
(20 mL), and brine (20 mL) then dried (Na2SO4) and concentrated.
The resulting mixture was purified by flash column chromatography
(petroleum ether) to give a yellowish solid; yield: 202 mg (63.0%);
mp 167–169 °C.
1H NMR (400 MHz, CDCl3): δ = 7.75 (d, J = 8.8 Hz, 2 H), 6.96 (d,
J = 1.6 Hz, 1 H), 6.88 (d, J = 8.8 Hz, 2 H), 6.77 (d, J = 1.6 Hz, 1 H),
6.24 (s, 1 H), 3.80 (s, 3 H).
(i) Haudecoeur, R.; Ahmed-Belkacem, A.; Yi, W.; Fortuné,
© Georg Thieme Verlag Stuttgart · New York
Synthesis 2012, 44, 2217–2224