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2067
6.74 (2H, s, H-2, H-6), 6.35 (1H, d, J = 16.0 Hz, H-8),
5.00 (2H, s, H-10), 4.27 (2H, q, J = 7.2 Hz, OCH2CH3-
9), 3.85 (6H, s, OCH3-3, OCH3-5), 1.34 (3H, t,
J = 7.2 Hz, OCH2CH3-9); 13C NMR (100 MHz,
CDCl3): d 166.8 (C-9), 153.5 (C-3, 5), 144.4 (C-7),
138.5 (C-1), 131.2 (C-40, 60), 130.2 (C-20), 130.0 (C-30,
70), 121.8 (C-50), 117.6 (C-8), 105.0 (C-2, 6), 74.1 (C-
10), 60.4 (OCH2CH3-9), 56.1 (OCH3-3, 5), 14.3
(OCH2CH3-9); HREI-MS calcd for C20H21BrO5
420.0572, found 420.0583.
4.2.2.12. 4-Propargyl sinapic acid ethyl ester (11l).
Yield: 70%; mp 89–91 ꢁC; 1H NMR (400 MHz, CDCl3):
d 7.60 (1H, d, J = 16.0 Hz, H-7), 6.75 (2H, s, H-2, H-6),
6.35 (1H, d, J = 16.0 Hz, H-8), 4.75 (2H, s, H-10), 4.27
(2H, q, J = 7.2 Hz, OCH2CH3-9), 3.87 (6H, s, OCH3-
3, OCH3-5), 2.44 (1H, s, H-30), 1.34 (3H, t, J = 7.2 Hz,
OCH2CH3-9); ESI-MS m/z [M+H]+ 291.
4.2.3. General procedure for the preparation of 4-O-
substituted sinapic acid 12a–12n. A KOH solution
(48 mg, 0.87 mmol in 3 mL H2O) was added to the
solution of compound 11 (0.29 mmol) in EtOH
(5 mL). The mixture was refluxed for 3 h and cooled
to room temperature. The reaction was monitored
by TLC using pet. ether/EtOAc/formic acid (4:1:0.05)
as the mobile phase. The organic solvent was re-
moved, the residue was diluted with water (2 mL)
and acidified by 1 M HCl to pH 5 to afford a white
suspension. The suspension was extracted by ether
(3· 20 mL) three times, washed with brine, and dried
over anhydrous Na2SO4. Removal of ether afforded 12
(65–96%).
4.2.2.7. 4-(40,50-Dichlorobenzyl) sinapic acid ethyl
ester (11g). Yield: 70%; mp 98–100 ꢁC; 1H NMR
(400 MHz, CDCl3): d 7.64 (1H, d, J = 1.6 Hz, H-30),
7.60 (1H, d, J = 16.0 Hz, H-7), 7.40 (1H, d, J =
8.4 Hz, H-60), 7.29 (1H, dd, J = 8.4, 1.6 Hz, H-70), 6.74
(2H, s, H-2, H-6), 6.35 (1H, d, J = 16.0 Hz, H-8), 5.00
(2H, s, H-10), 4.27 (2H, q, J = 7.2 Hz, OCH2CH3-9),
3.86 (6H, s, OCH3-3, OCH3-5), 1.34 (3H, t, J = 7.2 Hz,
OCH2CH3-9); ESI-MS m/z [M]+ 411.
4.2.2.8. 4-(50-Bromo-30-fluoro-benzyl) sinapic acid eth-
1
yl ester (11h). Yield: 70%; mp 109–111 ꢁC; H NMR
4.2.3.1. 4-(50-Ethoxy-benzyl) sinapic acid (12a). Yield:
(400 MHz, CDCl3): d 7.60 (1H, d, J = 16.0 Hz, H-7),
7.48 (1H, t, J = 8.0 Hz, H-70), 7.29 (1H, dd, J = 8.0,
1.6 Hz, H-60), 7.22 (1H, dd, J = 9.2, 1.6 Hz, H-40), 6.73
(2H, s, H-2, H-6), 6.35 (1H, d, J = 16.0 Hz, H-8), 5.08
(2H, s, H-10), 4.27 (2H, q, J = 7.2 Hz, OCH2CH3-9),
3.83 (6H, s, OCH3-3, OCH3-5), 1.34 (3H, t, J = 7.2 Hz,
OCH2CH3-9); ESI-MS m/z [M]+ 439.
1
96%; mp 135–137 ꢁC; H NMR (400 MHz, CDCl3): d
7.70 (1H, d, J = 15.6 Hz, H-7), 7.38 (2H, br d, J = 8.4,
6.8 Hz, H-30, 70), 6.85 (2H, br d, J = 8.4, 6.8 Hz, H-40,
60), 6.76 (2H, s, H-2, H-6), 6.35 (1H, d, J = 15.6 Hz,
H-8), 5.00 (2H, s, H-10), 4.03 (2H, q, J = 7.2 Hz,
OCH2CH3-50), 3.86 (6H, s, OCH3-3, OCH3-5), 1.40
(3H, t, J = 7.2 Hz, OCH2CH3-50); ESI-MS m/z
[M ꢀ H]ꢀ 357.
4.2.2.9. 4-(30-Phenyl-allyl) sinapic acid ethyl ester
1
(11i). Yield: 75%; mp 85–87 ꢁC; H NMR (400 MHz,
4.2.3.2. 4-Benzyl sinapic acid (12b). Yield: 96%; This
compound was identical to that reported by Kametani
et al.25
CDCl3): d 7.60 (1H, d, J = 16.0 Hz, H-7), 7.37 (2H,
dd, J = 7.2, 1.6 Hz, H-50, H-90), 7.31 (1H, ddd, J = 7.2,
7.2, 1.6 Hz, H-70); 7.25 (2H, ddd, J = 7.2, 7.2, 1.6 Hz,
H-60, 80), 6.75 (2H, s, H-2, H-6), 6.62 (1H, d,
J = 16.0 Hz, H-30), 6.47 (1H, dd, J = 16.0, 6.4 Hz, H-
20), 6.35 (1H, d, J = 16.0 Hz, H-30), 4.71 (2H, d,
J = 6.4 Hz, H-10), 4.26 (2H, q, J = 7.2 Hz, OCH2CH3-
9), 3.88 (6H, s, OCH3-3, OCH3-5), 1.34 (3H, t,
J = 7.2 Hz, OCH2CH3-9); ESI-MS m/z [M+H]+ 369.
4.2.3.3. 4-(30-Chloro-50-fluoro-benzyl) sinapic acid
(12c). Yield: 85%; mp 192–194 ꢁC; 1H NMR
(400 MHz, CDCl3): d 7.69 (1H, d, J = 16.0 Hz, H-7),
7.68 (1H, dd, J = 8.4, 5.2 Hz, H-70), 7.10 (1H, dd,
J = 8.4, 2.4 Hz, H-40), 6.98 (1H, dt, J = 8.4, 2.4 Hz, H-
60), 6.76 (2H, s, H-2, H-6), 6.36 (1H, d, J = 16.0 Hz,
H-8), 5.08 (2H, s, H-10), 3.85 (6H, s, OCH3-3, OCH3-
5); ESI-MS m/z [M ꢀ H]ꢀ 365.
4.2.2.10. 4-Hexadecyl sinapic acid ethyl ester (11j).
Yield: 77%; mp 64–65 ꢁC; 1H NMR (400 MHz, CDCl3):
d 7.61 (1H, d, J = 16.0 Hz, H-7), 6.76 (2H, s, H-2, H-6),
6.35 (1H, d, J = 16.0 Hz, H-8), 4.28 (2H, q, J = 7.2 Hz,
OCH2CH3-9), 4.01 (2H, t, J = 6.8 Hz, H-10), 3.88 (6H,
s, OCH3-3, OCH3-5), 1.76 (2H, m, H-20), 1.44 (2H, m,
H-30), 1.35 (3H, t, J = 7.2 Hz, OCH2CH3-9), 1.34 (2H,
m, H-40), 1.27 (22H, m, H-50–150), 0.89 (3H, t,
J = 7.2 Hz, H-160); ESI-MS m/z [M+H]+ 477.
4.2.3.4. 4-Geranyl sinapic acid (12d). Yield: 85%; This
compound was identical to that reported by Zhao et al.5
4.2.3.5. 4-(30-Bromobenzyl) sinapic acid (12e). Yield:
1
75%; mp 169–171 ꢁC; H NMR (400 MHz, CDCl3): d
7.72 (1H, d, J = 16.0 Hz, H-7), 7.72 (1H, dd, J = 8.4,
1.6 Hz, H-40), 7.54 (1H, dd, J = 8.4, 1.6 Hz, H-70), 7.33
(1H, ddd, J = 8.4, 8.4, 1.6 Hz, H-60), 7.16 (1H, ddd,
J = 8.4, 8.4, 1.6 Hz, H-50), 6.78 (2H, s, H-2, H-6), 6.37
(1H, d, J = 16.0 Hz, H-8), 5.15 (2H, s, H-10), 3.86 (6H,
s, OCH3-3, OCH3-5); ESI-MS m/z [M]ꢀ 393.
4.2.2.11. 4-(40-Bromobenzyl) sinapic acid ethyl ester
1
(11k). Yield: 70%; mp 80–81 ꢁC; H NMR (400 MHz,
CDCl3): d 7.70 (1H, s, H-30), 7.60 (1H, d, J = 16.0 Hz,
H-7), 7.43 (1H, d, J = 7.6 Hz, H-50), 7.37 (1H, d,
J = 7.6 Hz, H-70), 7.20 (1H, dd, J = 7.6, 7.6 Hz, H-60),
6.74 (2H, s, H-2, H-6), 6.35 (1H, d, J = 16.0 Hz, H-8),
5.01 (2H, s, H-10), 4.27 (2H, q, J = 7.2 Hz, OCH2CH3-
9), 3.86 (6H, s, OCH3-3, OCH3-5), 1.35 (3H, t,
J = 7.2 Hz, OCH2CH3-9); ESI-MS m/z [M]+ 421.
4.2.3.6. 4-(50-Bromobenzyl) sinapic acid (12f). Yield:
1
75%; mp 169–171 ꢁC; H NMR (400 MHz, CDCl3): d
7.70 (1H, d, J = 16.0 Hz, H-7), 7.47 (2H, d, J = 8.4 Hz,
H-30, 70), 7.35 (2H, d, J = 8.4 Hz, H-40, H-60), 6.76
(2H, s, H-2, H-6), 6.36 (1H, d, J = 16.0 Hz, H-8), 5.01