N. Jun et al. / Bioorg. Med. Chem. 15 (2007) 2396–2402
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3.2.4. 20,3,4,40,60-Pentahydroxychalcone (4). Yield: 41%;
yellow powders; mp 157–158 ꢁC; EI-HR-MS m/z:
288.0602 (calcd for C15H12O6, 288.0634); 1H NMR (ace-
tone-d6) d (ppm): 5.95 (2H, s, H-30 and 50), 6.88 (1H, d,
J = 8.1 Hz, H-5), 7.07 (1H, dd, J = 8.1, 1.8 Hz, H-6),
7.19 (1H, d, J = 1.8 Hz, H-2), 7.69 (1H, d, J = 15.5 Hz,
H-b), 8.05 (1H, d, J = 15.5 Hz, H-a).
NMR (methanol-d4) d (ppm): 3.87 and 3.90 (each 3H,
s, 2 · OCH3), 5.84 (2H, s, H-30 and 50), 6.99 (1H, d,
J = 8.3 Hz, H-5), 7.22 (1H, dd, J = 8.3, 2.0 Hz, H-6),
7.22 (1H, d, J = 2.0 Hz, H-2), 7.69 (1H, d, J = 15.5 Hz,
H-b), 8.10 (1H, d, J = 15.5 Hz, H-a).
3.2.12. 20,3,4-Trihydroxy-40,60-dimethoxychalcone (12).
Yield: 67%; yellow powders; mp 174–175 ꢁC; EI-HR-
MS m/z: 316.0926 (calcd for C17H16O6, 316.0947); H
1
3.2.5. 20,3,4,40,5,60-Hexahydroxychalcone (5). Yield:
25%; yellow powders; mp 179–180 ꢁC; EI-HR-MS m/z:
304.0566 (calcd for C15H12O7, 304.0583); 1H NMR (ace-
tone-d6) d (ppm): 5.95 (2H, s, H-30 and 50), 6.77 (2H, s,
H-2 and 6), 7.61 (1H, d, J = 15.6 Hz, H-b), 8.03 (1H, d,
J = 15.6 Hz, H-a).
NMR (acetone-d6) d (ppm): 3.86 and 4.00 (each 3H, s,
2 · OCH3), 6.08 (1H, d, J = 2.5 Hz, H-50), 6.11 (1H, d,
J = 2.5 Hz, H-30), 6.89 (1H, d, J = 8.1 Hz, H-5), 7.11
(1H
, dd, J = 8.1, 2.0 Hz, H-6), 7.24 (1H, d,
J = 2.0 Hz, H-2), 7.69 (1H, d, J = 15.5 Hz, H-b), 7.83
(1H, d, J = 15.5 Hz, H-a).
3.2.6. 20,3,4,40,60-Pentahydroxychalcone (6). Yield: 41%;
yellow powders; mp 157–158 ꢁC; EI-HR-MS m/z:
288.0602 (calcd for C15H12O6, 288.0634); 1H NMR (ace-
tone-d6) d (ppm): 5.95 (2H, s, H-30 and 50), 6.88 (1H, d,
J = 8.1 Hz, H-5), 7.07 (1H, dd, J = 8.1, 1.8 Hz, H-6),
7.19 (1H, d, J = 1.8 Hz, H-2), 7.69 (1H, d, J = 15.5 Hz,
H-b), 8.05 (1H, d, J = 15.5 Hz, H-a).
3.2.13. 2,20,4,40-Tetrahydroxychalcone (13). Yield: 53%;
yellow powders; mp 178–179 ꢁC; EI-HR-MS m/z:
272.0670 (calcd for C15H12O5, 272.0685); 1H NMR
(methanol-d4) d (ppm): 6.27 (1H, d, J = 2.4 Hz, H-3 or
30), 6.34 (1H, d, J = 2.4 Hz, H-3 or 30), 6.36 (1H, dd,
J = 8.6, 2.4 Hz, H-5 or 50), 6.39 (1H, dd, J = 8.8,
2.5 Hz, H-5 or 50), 7.50 (1H, d, J = 8.6 Hz, H-6 or 60),
7.69 (1H, d, J = 15.2 Hz, H-b), 7.88 (1H, d, J = 8.8 Hz,
H-6 or 60), 8.08 (1H, d, J = 15.2 Hz, H-a).
3.2.7. 3,30,4,40-Tetrahydroxychalcone (7). Yield: 63%;
yellow powders; mp 170–171 ꢁC; EI-HR-MS m/z:
272.0650 (calcd for C15H12O5, 272.0685); 1H NMR
(methanol-d4) d (ppm): 6.76 (1H, d, J = 8.1 Hz, H-5 or
50), 6.82 (1H, d, J = 8.2 Hz, H-5 or 50), 7.03 (1H, dd,
J = 8.1, 2.2 Hz, H-6 or 60), 7.12 (1H, d, J = 2.2 Hz, H-
2 or 20), 7.41 (1H, d, J = 15.5 Hz, H-b), 7.45 (1H, d,
J = 2.2 Hz, H-2 or 20), 7.49 (1H, dd, J = 8.2, 2.2 Hz,
H-6 or 60), 7.57 (1H, d, J = 15.5 Hz, H-a).
3.2.14. 2,20,4,40-Tetrahydroxy-60-methoxychalcone (14).
Yield: 12%; yellow powders; FD-HR-MS m/z: 302.0806
(calcd for C16H14O6, 302.0790); 1H NMR (acetone-d6) d
(ppm): 3.93 (3H, s, OCH3), 5.97 (1H, d, J = 2.2 Hz, H-
50), 6.04 (1H, d, J = 2.2 Hz, H-30), 6.44 (1H, dd,
J = 8.1, 1.9 Hz, H-5), 6.49 (1H, d, J = 1.9 Hz, H-3),
6.53 (1H, d, J = 8.1 Hz, H-6), 7.98 (1H, d, J = 15.7 Hz,
H-b), 8.14 (1H, d, J = 15.7 Hz, H-a).
3.2.8. 20,3,4-Trihydroxychalcone (8). Yield: 74%; yellow
powders; mp 169–170 ꢁC; EI-HR-MS m/z: 256.0714
(calcd for C15H12O4, 256.0736); 1H NMR (methanol-d4)
d (ppm): 6.83 (1H, d, J = 8.3 Hz, H-5), 6.94–6.99 (2H,
m, H-30 and 50), 7.15 (1H, dd, J = 8.3, 2.3 Hz, H-6), 7.22
(1H, d, J = 2.3 Hz, H-2), 7.49 (1H, dt, J = 7.4 (t),
1.7 Hz, H-40), 7.65 (1H, d, J = 15.3 Hz, H-b), 7.81 (1H,
d, J = 15.3 Hz, H-a), 8.08 (1H, dd, J = 7.9, 1.7 Hz, H-60).
3.3. The preparation of 2,20,4,40,60-pentahydroxychalcone
15
To a stirred solution of15a (232 mg, 0.5 mmol) in meth-
anol (10 mL) was added dropwise 3 M HCl (4 mL). The
mixture was refluxed for 10 min, diluted with water, and
extracted with ethyl acetate. The organic layer was suc-
cessively washed with water and brine, dried over anhy-
drous Na2SO4, and evaporated under reduced pressure.
The residue was purified by silica gel column chroma-
tography (chloroform/methanol = 1:50) to give 112 mg
of 20,40,6,8-hydroxyflavanone 15b in 78% yield: FD-
3.2.9. 20,40,60-Trihydroxy-3,4-dimethoxychalcone (9). Yield:
53%; yellow powders; mp 91–92 ꢁC; EI-HR-MS m/z:
316.0943 (calcd for C17H16O6, 316.0947); 1H NMR
(methanol-d4) d (ppm): 3.87 and 3.90 (each 3H, s,
2 · OCH3), 5.84 (2H, s, H-30 and 50), 6.99 (1H, d,
J = 8.3 Hz, H-5), 7.22 (1H, dd, J = 8.3, 2.0 Hz, H-6),
7.22 (1H, d, J = 2.0 Hz, H-2), 7.69 (1H, d, J = 15.5 Hz,
H-b), 8.10 (1H, d, J = 15.5 Hz, H-a).
1
MS m/z (%): 288 (100, [M]+); H NMR (acetone-d6) d
(ppm): 2.66 (1H, dd, J = 16, 2.9 Hz, H-3eq), 3.16 (1H,
dd, J = 13.6, 16 Hz, H-3ax), 5.69 (1H, dd, J = 13.6,
2.9 Hz, H-2), 5.95 (2H, s, H-6 and 8), 6.42 (1 H, dd,
J = 8.4, 1.8 Hz, H-50), 6.48 (1H, d, J = 1.8 Hz, H-30),
7.48 (1H, d, J = 8.4 Hz, H-60).
3.2.10. 2,20,3-Trihydroxy-40,60-dimethoxychalcone (10).
Yield: 60%; yellow powders; mp 175–176 ꢁC; EI-HR-
MS m/z: 316.0918 (calcd for C17H16O6, 316.0947); H
1
NMR (acetone-d6) d (ppm): 3.83, 3.94 (each 3H, s,
2 · OCH3), 6.04 (1H, d, J = 2.4 Hz, H-50), 6.07 (1H, d,
J = 2.4 Hz, H-30), 6.68 (1H, dd, J = 8.1, 7.2 Hz, H-5),
6.87 (1H, d, J = 7.2 Hz, H-4), 7.11 (1H, d, J = 8.1 Hz,
H-6), 8.12 (2H, m, H-a and b ).
To a stirred solution of 4 M KOH (10 mL) cooled to
0 ꢁC in an ice bath was added dropwise a solution of
15a (72 mg, 0.25 mmol) in ethanol (10 mL) under argon,
and then the reaction mixture was kept at room temper-
ature for 30 min. The mixture was poured into ice-water
(10 mL), adjusted to pH 3–4 with 1 M HCl, and then
extracted with ethyl acetate. The organic layer was suc-
cessively washed with water and saturated brine, dried
over anhydrous Na2SO4. After evaporation, the residue
3.2.11. 20,3,4,5,-Tetrahydroxy-40,60-dimethoxychalcone
(11). Yield: 25%; yellow powders; mp 91–92 ꢁC; EI-HR-
MS m/z: 316.0943 (calcd for C17H16O6, 316.0947); H
1