W. Peng and Y.-f. Yao
acid (110 mL) after it was stirred for 6 h at room temperature.
13C NMR (CD3OD, 100 MHz)d28.0, 28.1 (t, J = 35.3 Hz); 64.2,
The resulting mixture was concentrated to about half of its 65.2, 75.8, 79.9, 94.2, 94.6, 95.3, 98.3, 98.7, 117.0, 120.8, 122.5,
original volume in vacuo and extracted with ethyl acetate 125.1, 127.6, 130.2, 133.2, 145.1, 149.7, 154.1, 155.3, 156.0, 156.3,
(3 ꢀ 50 mL). The combined extracts were washed three times 156.5, 156.7, 156.8, 184.4;
with distilled water (50 mL), dried (Na2SO4) and evaporated to
IR (KBr) 3387, 2921, 2850, 1693, 1630, 1604, 1516, 1469, 1421,
dryness. The residue was purified by silica gel column 1329, 1260, 1230, 1143, 1100, 1062, 808 cm-1;
chromatography with CH2Cl2/ethyl acetate (3:1 followed by
LRMS (ESI) 564 [M-1]ꢁ; HRMS (ESI) Found 566.1403 for [M11]1,
1.5:1; v/v) as eluent to give 9 (92 mg, 83% yield). Consequently, Calculated for C29H24DO12 566.1406.
into the solution of 9 in THF (15 mL), LiAlH4 (107 mg, 2.8 mmol)
was added. The reaction mixture was poured into ice-cold water
Acknowledgement
(100 mL) after it was stirred under room temperature for 24 h,
and then the pH value was adjusted to 1.0 by addition of 5%
The author thanks Dr Ya Cai, former director of Unilever
phosphoric acid. The mixture was then extracted with ethyl
acetate (3 ꢀ 50 mL). The combined extracts were dried (Na2SO4)
and concentrated. The residue was chromatographed on a
column of silica gel with CH2Cl2/AcOEt/MeOH (10:6:3; v/v/v) as
eluent to give product 11 (D-EC, 71 mg, 88% yield).
1H NMR (CD3OD, 400 MHz)d2.19 (s, 1H); 4.17 (s, 1H); 4.81
(s, 1H); 5.91 (s, 1H); 5.93 (s, 1H); 6.74–6.81 (m, 2H); 6.97 (s, 1H);
13C NMR (CD3OD, 100 MHz)d27.9, 66.0, 78.5, 94.5, 95.0, 98.6,
113.9, 114.5, 118.0, 130.9, 144.4, 144.6, 156.0, 156.3, 156.6.
Research China, for his general advice and Dr Hong-Qiang Wang,
current director of Unilever Research China, for his generous
support during the progress of this study. We are also grateful to
natural product team of URC for supply of catechins and analytic
team for their analytic support.
The second procedure for the synthesis of deuterium-labelled EC 11 References
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