C.-M. Lin et al. / Bioorg. Med. Chem. 14 (2006) 4402–4409
4407
4
(
8.54, 59.78, 94.79, 103.06, 164.21 164.37, 208.40; MS
FAB) m/z 237 (MH , base).
4.3.4.
(7). Starting from 16 (0.25 g, 1.50 mmol), 7 (0.13 g,
5%) was obtained as a canary-yellow solid. Mp: 257–
5,7-Dihydroxy-6-acetoyl-4-ethyl-chromen-2-one
+
3
4.2.7. 2,4,6-Trihydroxy-benzophenone (20). Starting from
benzoyl chloride (1.84 mL, 16 mmol), 20 (1.6 g, 44%) was
260 °C; R 0.38 (CH Cl /MeOH 10:1); IR (KBr) 3000–
f
2
2
À1
1
3500, 1713, 1627 cm ; H NMR (500 MHz, DMSO-d )
6
1
obtained as a yellow solid. H NMR (500 MHz, DMSO-
d 1.16 (t, J = 7.3 Hz, 3H), 2.68 (s, 3H), 2.93 (q,
J = 7.3 Hz, 3H), 5.94 (s, 1H), 6.30 (s, 1H); C NMR
1
3
d6) d 5.84 (s, 2H), 7.43 (t, J = 7.7 Hz, 2H), 7.51 (t,
J = 7.4 Hz, 1H), 7.61 (d, J = 7.7 Hz, 2H), 9.82 (s, 1H),
(125 MHz, DMSO-d ) d 13.5, 28.4, 33.0, 94.7, 101.3,
6
1
3
1
1
1
0.08 (s, 2H); C NMR (125 MHz, DMSO-d ) d 94.43,
106.5, 108.3, 159.2, 159.9, 160.1, 163.6, 165.2, 205.2;
MS (EI, 70 eV) m/z 248 (M ), 205 (base peak); HRMS
6
+
05.74, 128.04, 128.47, 131.81, 139.86, 159.40, 161.87,
96.52; MS (FAB) m/z 231 (MH ), 154 (base peak).
+
+
(EI) calculated for C H O : 248.0679, found:
1
4
14
5
248.0688.
4
.3. Preparation of 6-acyl-5,7-dihydroxycoumarins
4.3.5.
6-(3,3-Dimethyl-butyryl)-5,7-dihydroxy-4-ethyl-
Concentrated H SO (0.2 mL) was added to a mixture
2
chromen-2- one (8). Starting from 17 (0.25 g, 1.11 mmol),
8 (0.65 g, 39%) was obtained as a canary-yellow solid.
Mp: 231–234 °C; R 0.38 (CH Cl /MeOH 10:1); IR
4
of acylphloroglucinol (1 mmol) and benzoyl acid ester
1.1 mmol) in glacial HOAc (3 mL) and stirred for 2 h
(
f
2
2
À1
1
at room temperature. The precipitate was filtered,
washed with water, and crystallized with MeOH to give
the product.
(KBr) 3000–3500, 1705, 1625 cm
(500 MHz, DMSO-d6)
J = 7.3 Hz, 3H), 2.94 (q, J = 7.2 Hz, 3H), 5.94 (s, 1H),
;
H
NMR
d
1.01 (s, 9H), 1.16 (t,
1
3
6
.29 (s, 1H); C NMR (125 MHz, DMSO-d ) d 13.6,
6
4
.3.1. 5,7-Dihydroxy-6-(3-methyl-butyryl)-4-phenyl-chro-
men-2-one (3). Starting from 14 (4.4 g, 20.9 mmol), 3
0.83 g, 12%) was obtained as a canary-yellow solid.
28.5, 29.7, 31.8, 54.1, 94.9, 101.5, 107.6, 159.3, 159.6,
160.1, 163.1, 165.1, 207.6; MS (EI, 70 eV) m/z 304
+
(M ), 233 (base peak); HRMS (EI) calculated for
(
+
C H O : 304.1305, found: 304.1311.
Mp: 253–255 °C; R 0.50 (CH Cl /MeOH 10:1); IR
f
2
2
19 16
5
À1
1
(
neat) 3000–3500, 1689, 1616 cm
;
H
NMR
(
(
1
(
1
1
7
500 MHz, DMSO-d ) d 0.89 (s, 3H), 0.90 (s, 3H), 2.11
4.3.6. 6-(Phenylacetoyl)-5,7-dihydroxy-4-phenyl-chro-
men-2-one (9). Starting from 18 (0.25 g, 1.03 mmol), 9
6
m, 1H), 2.95 (d, J = 6.5 Hz, 2H), 5.84 (s, 1H), 6.37 (s,
1
3
H), 7.31–7.33 (m, 2H), 7.37–7.39 (m, 3H); C NMR
(0.14 g, 42%) was obtained as a yellow solid. Mp: 244–
246 °C; R 0.50 (EtOAc/n-hexane 1:1); IR (KBr) 3000–
125 MHz, DMSO-d ) d 22.47, 24.62, 52.35, 94.70,
6
f
À1
1
3500, 1690, 1620 cm ; H NMR (500 MHz, DMSO-
00.65, 106.49, 111.39, 127.15, 127.44, 128.04, 138.93,
55.56, 158.86, 159.61, 163.80, 164.68, 207.07; MS (EI,
d6) d 1.15 (t, J = 7.2 Hz, 3H), 2.93 (q, J = 7.2 Hz, 3H),
5.95 (s, 1H), 6.33 (s, 1H), 7.23–7.32 (m, 5H), 12.1 (s,
+
0 eV) m/z 338 (M ), 170 (base peak); HRMS (EI) cal-
+
13
culated for C H O : 338.1149, found: 338.1154.
2
1H), 15.3 (s, 1H); C NMR (125 MHz, DMSO-d ) d
0
18
5
6
13.6, 49.7, 94.9, 101.5, 106.4, 108.4, 126.5, 128.2,
129.8, 135.0, 159.2, 159.9, 160.1, 163.3, 165.3, 205.1;
4
.3.2. 5,7-Dihydroxy-6-(3-methyl-butyryl)-4-ethyl-chro-
men-2-one (5). Starting from 14 (0.2 g, 0.95 mmol), 5
0.10 g, 36%) was obtained as a canary-yellow solid.
+
MS (EI, 70 eV) m/z 324 (M ), 233 (base peak); HRMS
+
(EI) calculated for C H O : 324.0992, found:
324.1001.
(
1
9
16
5
Mp: 229–232 °C; R 0.50 (EtOAc/n-hexane 1:1); IR
f
À1
1
(
(
(
KBr) 3000–3500, 1686, 1616 cm
500 MHz, DMSO-d ) d 0.92 (s, 3H), 0.93 (s, 3H), 1.16
t, J = 7.4 Hz, 3H), 2.17 (m, 1H), 2.94 (q, J = 7.2 Hz,
H), 2.98 (d, J = 6.9 Hz, 2H), 5.94 (s, 1H), 6.29 (s, 1H),
;
H
NMR
4.3.7. 6-(2-Cyclohexanoyl)-5,7-dihydroxy-4-ethyl-chro-
men-2-one (10). Starting from 19 (0.31 g, 1.24 mmol),
10 (0.15 g, 34%) was obtained as a yellow solid. Mp:
233–235 °C; R 0.38 (CH Cl /MeOH 10:1); IR (KBr)
6
3
1
1.97 (s, 1H), 15.53 (s, 1H); C NMR (125 MHz,
3
1
f
2
2
À1
1
DMSO-d ) d 13.52, 22.53, 24.64, 28.47, 52.43, 94.78,
3000–3500, 1699, 1607 cm
;
H NMR (500 MHz,
6
1
01.46, 106.41, 108.25, 159.24, 159.698, 160.10, 163.25,
65.35, 207.27; MS (EI, 70 eV) m/z 290 (M ), 233 (base
DMSO-d ) d 1.14–1.28 (m, 4H), 1.28–1.35 (m, 4H),
6
+
1
peak); HRMS (EI) calculated for C H O : 290.1149,
found: 290.1162.
1.67 (d, J = 12.6 Hz, 1H), 1.75–1.78 (m, 2H), 1.87 ( d,
J = 10.1 Hz, 2H), 2.93 (q, J = 7.2 Hz, 2H), 3.66 (m,
+
1
6
18
5
1
3
1H), 5.94 (s, 1H), 6.30 (s, 1H), 12.0 (s, 1H); C NMR
125 MHz, DMSO-d ) d 13.6, 25.6, 25.6, 28.5, 29.0,
49.3, 94.9, 101.6, 105.7, 108.3, 159.3, 159.6, 160.1,
(
6
4
(
.3.3. 5,7-Dihydroxy-6-propyryl-4-ethyl-chromen-2-one
6). Starting from 15 (0.25 g, 1.37 mmol), 6 (0.13 g,
+
162.9, 165.6, 210.8; MS (EI, 70 eV) m/z 316 (M ), 233
(base peak); HRMS (EI) calculated for C H O :
316.1305, found: 316.1308.
+
3
2
3
6%) was obtained as a canary-yellow solid. Mp:
59–262 °C; R 0.61 (EtOAc/n-hexane 1:1); IR (KBr)
1
4
14
5
f
À1
1
000–3500, 1678, 1624 cm
d
;
1.08 (t, J = 7.0 Hz, 3H), 1.16 (t,
H NMR (500 MHz,
DMSO-d6)
4.3.8. 5,7-Dihydroxy-6-(3-methyl-butyryl)-4-methyl-chro-
men-2-one (11). Starting from 14 (0.65 g, 3.11 mmol), 11
(0.46 g, 54%) was obtained as a canary-yellow solid.
J = 7.3 Hz, 3H), 2.93 (q, J = 7.3 Hz, 3H), 3.13 (q,
J = 7.0 Hz, 2H), 5.93 (s, 1H), 6.30 (s, 1H), 11.9 (s,
1
3
1
8
1
2
H), 15.5 (s, 1H); C NMR (125 MHz, DMSO-d ) d
Mp: 272–2274 °C; R 0.50 (EtOAc/n-hexane 1:1); IR
6
f
À1 1
.33, 13.5, 28.5, 37.2, 94.7, 101.4, 106.2, 108.3, 159.3,
59.6, 160.1, 163.4, 165.1, 208.2; MS (EI, 70 eV) m/z
(KBr) 3000–3500, 1678, 1611 cm ; H NMR
(500 MHz, DMSO-d ) d 0.91 (s, 3H), 0.93 (s, 3H), 2.16
6
+
62 (M ), 233 (base peak); HRMS (EI) calculated for
(m, 1H), 2.51 (s, 3H), 2.98 (d, J = 7.0 Hz, 2H), 5.96 (s,
1H), 6.27 (s, 1H), 11.97 (s, 1H), 15.53 (s, 1H);
+
13
C H O : 262.0836, found: 262.0841.
4
C
1
14
5