Journal of Agricultural and Food Chemistry
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C (10% w/w) under N2. The mixture was flushed with H2 three times,
and stirred at room temperature under H2 for 24 h. After the reaction
was completed, the mixture was filtered through a short pad of silica
gel. The filtrate was evaporated under reduced pressure to give the
desired compounds 6−10.
H-2), 6.21 (2H, d, J = 2.0 Hz, H-4/6), 2.45 (2H, t, J = 7.7 Hz, H-1′),
1.54 (2H, m, H-2′), 1.27−1.24 (12H, m, ranged from H-3′ to H-8′),
and 0.87 (3H, t, J = 6.9 Hz, H-9′); 13C NMR (125 MHz,
CDCl3+CD3OD) δ 156.6 (s, C-1/3), 100.1 (d, C-2), 108.0 (d, C-4/
6), 146.1 (s, C-5), 35.8 (t, C-1′), 31.0 (t, C-2′), 29.2 (t, C-3′), 29.5−
29.3 (t, ranged from C-4′ to C-6′), 31.9 (t, C-7′), 22.7 (t, C-8′), and
14.1 (q, C-9′); positive APCIMS, m/z 237 [M + H]+.
1,3-Dimethoxy-5-nonylbenzene (6). Procedure B was followed
by using 1,3-dimethoxy-5-(non-1-enyl)benzene (3.8 g, 14.5 mmol)
and Pd/C (10% w/w, 380 mg) in a mixture of chloroform/methanol
(20 mL, 1:1). The resulting filtration was evaporated to give the title
compound 1,3-dimethoxy-5-nonylbenzene (6) (3.3 g, yield: 85%) as a
5-n-Undecylresorcinol (12). Procedure C was followed by using
1,3-dimethoxy-5-undecylbenzene (2.3 g, 7.9 mmol) and a solution of
BBr3 in DCM (1 M, 15.8 mL, 15.8 mmol). The residue was purified by
column chromatography (DCM/MeOH = 30:1) to give the title
compound 5-n-undecylresorcinol (12) (2.0 g, yield: 90%) as a white
solid: 1H NMR (700 MHz, CDCl3+CD3OD) δ 6.14 (1H, t, J = 2.2 Hz,
H-2), 6.20 (2H, d, J = 2.2 Hz, H-4/6), 2.43 (2H, t, J = 7.7 Hz, H-1′),
1.53 (2H, m, H-2′), 1.26−1.22 (16H, m, ranged from H-3′ to H-10′),
and 0.86 (3H, t, J = 6.9 Hz, H-11′); 13C NMR (125 MHz,
CDCl3+CD3OD) δ 156.9 (s, C-1/3), 100.1 (d, C-2), 107.6 (d, C-4/6),
145.9 (s, C-5), 35.9 (t, C-1′), 31.1 (t, C-2′), 29.3 (t, C-3′), 29.7−29.3
(t, ranged from C-4′ to C-8′), 31.9 (t, C-9′), 22.6 (t, C-10′), and 14.1
(q, C-11′); positive APCIMS, m/z 265 [M + H]+.
1
colorless oil: H NMR (600 MHz, CDCl3) δ 6.30 (1H, t, J = 2.2 Hz,
H-2), 6.35 (2H, d, J = 2.2 Hz, H-4/6), 2.54 (2H, t, J = 7.7 Hz, H-1′),
1.60 (2H, m, H-2′), 1.33−1.26 (12H, m, ranged from H-3′ to H-8′),
0.88 (3H, t, J = 6.8 Hz, H-9′), and 3.78 (6H, s, OMe-1/3); positive
APCIMS, m/z 265 [M + H]+.
1,3-Dimethoxy-5-undecylbenzene (7). Procedure B was
followed by using 1,3-dimethoxy-5-(undec-1-enyl)benzene (3.0 g,
10.3 mmol) and Pd/C (10% w/w, 300 mg) in a mixture of
chloroform/methanol (20 mL, 1:1). The resulting filtration was
evaporated to give the title compound 1,3-dimethoxy-5-undecylben-
1
zene (7) (2.6 g, yield: 86%) as a white solid: H NMR (700 MHz,
5-n-Tridecylresorcinol (13). Procedure C was followed by using
1,3-dimethoxy-5-tridecylbenzene (3.0 g, 9.4 mmol) and a solution of
BBr3 in DCM (1 M, 18.8 mL, 18.8 mmol). The residue was purified by
column chromatography (DCM/MeOH = 30:1) to give the title
compound 5-n-tridecylresorcinol (13) (2.5 g, yield: 91%) as a white
solid: 1H NMR (700 MHz, CDCl3+CD3OD) δ 6.12 (1H, t, J = 2.2 Hz,
H-2), 6.18 (2H, d, J = 2.2 Hz, H-4/6), 2.43 (2H, t, J = 7.7 Hz, H-1′),
1.53 (2H, m, H-2′), 1.26−1.22 (20H, m, ranged from H-3′ to H-12′),
and 0.85 (3H, t, J = 6.8 Hz, H-13′); 13C NMR (125 MHz,
CDCl3+CD3OD) δ 157.0 (s, C-1/3), 100.0 (d, C-2), 107.5 (d, C-4/6),
145.8 (s, C-5), 35.8 (t, C-1′), 31.1 (t, C-2′), 29.3 (t, C-3′), 29.8−29.3
(t, ranged from C-4′ to C-10′), 31.9 (t, C-11′), 22.6 (t, C-12′), and
14.1 (q, C-13′); positive APCIMS, m/z 293 [M + H]+.
CDCl3) δ 6.29 (1H, t, J = 2.2 Hz, H-2), 6.34 (2H, d, J = 2.2 Hz, H-4/
6), 2.53 (2H, t, J = 7.6 Hz, H-1′), 1.59 (2H, m, H-2′), 1.33−1.24
(16H, m, ranged from H-3′ to H-10′), 0.87 (3H, t, J = 6.9 Hz, H-11′),
and 3.77 (6H, s, OMe-1/3); positive APCIMS, m/z 293 [M + H]+.
1,3-Dimethoxy-5-tridecylbenzene (8). Procedure B was fol-
lowed by using 1,3-dimethoxy-5-(tridec-1-enyl)benzene (3.6 g, 11.3
mmol) and Pd/C (10% w/w, 360 mg) in a mixture of chloroform/
methanol (20 mL, 1:1). The resulting filtration was evaporated to give
the title compound 1,3-dimethoxy-5-tridecylbenzene (8) (3.3 g, yield:
91%) as a white solid: 1H NMR (700 MHz, CDCl3) δ 6.29 (1H, t, J =
2.2 Hz, H-2), 6.34 (2H, d, J = 2.2 Hz, H-4/6), 2.53 (2H, t, J = 7.7 Hz,
H-1′), 1.59 (2H, m, H-2′), 1.33−1.24 (20H, m, ranged from H-3′ to
H-12′), 0.87 (3H, t, J = 6.9 Hz, H-13′), and 3.77 (6H, s, OMe-1/3);
positive APCIMS, m/z 321 [M + H]+.
5-n-Pentadecylresorcinol (14). Procedure C was followed by
using 1,3-dimethoxy-5-pentadecylbenzene (2.6 g, 7.5 mmol) and a
solution of BBr3 in DCM (1 M, 14.9 mL, 14.9 mmol). The residue was
purified by column chromatography (DCM/MeOH = 30:1) to give
the title compound 5-n-pentadecylresorcinol (14) (2.2 g, yield: 90%)
as a white solid: 1H NMR (700 MHz, CDCl3+CD3OD) δ 6.07 (1H, t,
J = 2.2 Hz, H-2), 6.14 (2H, d, J = 2.2 Hz, H-4/6), 2.39 (2H, t, J = 7.7
Hz, H-1′), 1.49 (2H, m, H-2′), 1.24−1.18 (24H, m, ranged from H-3′
to H-14′), and 0.82 (3H, t, J = 6.8 Hz, H-15′); 13C NMR (125 MHz,
CDCl3+CD3OD) δ 157.2 (s, C-1/3), 99.8 (d, C-2), 107.2 (d, C-4/6),
145.6 (s, C-5), 35.8 (t, C-1′), 31.1 (t, C-2′), 29.2 (t, C-3′), 29.7−29.3
(t, ranged from C-4′ to C-12′), 31.8 (t, C-13′), 22.6 (t, C-14′), and
14.0 (q, C-15′); positive APCIMS, m/z 321 [M + H]+.
1,3-Dimethoxy-5-pentadecylbenzene (9). Procedure B was
followed by using 1,3-dimethoxy-5-(pentadec-1-enyl)benzene (4.0 g,
11.6 mmol) and Pd/C (10% w/w, 400 mg) in a mixture of
chloroform/methanol (20 mL, 1:1). The resulting filtration was
evaporated to give the title compound 1,3-dimethoxy-5-pentadecyl-
benzene (9) (3.3 g, yield: 80%) as a white solid: 1H NMR (700 MHz,
CDCl3) δ 6.29 (1H, t, J = 2.2 Hz, H-2), 6.34 (2H, d, J = 2.2 Hz, H-4/
6), 2.53 (2H, t, J = 7.7 Hz, H-1′), 1.59 (2H, m, H-2′), 1.33−1.24
(24H, m, ranged from H-3′ to H-14′), 0.88 (3H, t, J = 6.9 Hz, H-15′),
and 3.77 (6H, s, OMe-1/3); positive APCIMS, m/z 349 [M + H]+.
1,3-Dimethoxy-5-heptadecylbenzene (10). Procedure B was
followed by using 1,3-dimethoxy-5-(heptadec-1-enyl)benzene (4.0 g,
10.7 mmol) and Pd/C (10% w/w, 400 mg) in a mixture of
chloroform/methanol (20 mL, 1:1). The resulting filtration was
evaporated to give the title compound 1,3-dimethoxy-5-heptadecyl-
benzene (10) (3.2 g, yield: 80%) as a white solid: 1H NMR (700 MHz,
CDCl3) δ 6.29 (1H, t, J = 2.2 Hz, H-2), 6.34 (2H, d, J = 2.2 Hz, H-4/
6), 2.53 (2H, t, J = 7.7 Hz, H-1′), 1.59 (2H, m, H-2′), 1.33−1.24
(28H, m, ranged from H-3′ to H-16′), 0.88 (3H, t, J = 6.9 Hz, H-17′),
and 3.77 (6H, s, OMe-1/3); positive APCIMS, m/z 377 [M + H]+.
General Procedure C for the Demethylation by BBr3. Methyl
ethers (1.0 equiv) were dissolved in dichloromethane (DCM) (50
mL). A solution of BBr3 in DCM (1 M, 2.0−3.5 equiv) was added at 0
°C slowly. After the addition was completed, the reaction solution was
allowed to warm to room temperature overnight and quenched by
water (50 mL). The organic phase solvent was washed with water and
brine, dried over Na2SO4, and filtered. The filtrate was evaporated
under reduced pressure to give a residue, which was purified by
column chromatography or pre-TLC to give the desired compounds.
5-n-Nonylresorcinol (11). Procedure C was followed by using
1,3-dimethoxy-5-nonylbenzene (3.6 g, 13.6 mmol) and a solution of
BBr3 in DCM (1M, 34.1 mL, 34.1 mmol). The residue was purified by
column chromatography (DCM/MeOH = 50:1) to give the title
compound 5-n-nonylresorcinol (11) (2.7 g, yield: 84%) as a white
solid: 1H NMR (600 MHz, CDCl3+CD3OD) δ 6.15 (1H, t, J = 2.0 Hz,
5-n-Heptadecylresorcinol (15). Procedure C was followed by
using 1,3-dimethoxy-5-heptadecylbenzene (3.0 g, 7.9 mmol) and a
solution of BBr3 in DCM (1 M, 19.9 mL, 19.9 mmol). The residue was
purified by column chromatography (DCM/MeOH = 30:1) to give
the title compound 5-n-heptadecylresorcinol (15) (2.7 g, yield: 95%)
as a white solid: 1H NMR (600 MHz, CDCl3+CD3OD) δ 6.13 (1H, t,
J = 2.2 Hz, H-2), 6.19 (2H, d, J = 2.2 Hz, H-4/6), 2.43 (2H, t, J = 7.7
Hz, H-1′), 1.52 (2H, m, H-2′), 1.30−1.24 (28H, m, ranged from H-3′
to H-16′), and 0.86 (3H, t, J = 6.7 Hz, H-17′); 13C NMR (125 MHz,
CDCl3+CD3OD) δ 157.2 (s, C-1/3), 99.9 (d, C-2), 107.3 (d, C-4/6),
145.7 (s, C-5), 35.9 (t, C-1′), 31.1 (t, C-2′), 29.3 (t, C-3′), 29.7−29.4
(t, ranged from C-4′ to C-14′), 31.9 (t, C-15′), 22.7 (t, C-16′), and
14.1 (q, C-17′); positive APCIMS, m/z 349 [M + H]+.
General Procedure D for the Synthesis of the Secondary
Alcohols by Grignard Reaction. A flame-dried 100 mL three-
necked flask, equipped with a condenser, was charged with magnesium
turnings (4.04 equiv), a small piece of iodine, and 20 mL of dry THF
under N2. A few drops of a solution of alkylbromide in THF were
added to trigger the reaction, then the reaction mixture was heated to
60 °C, and the rest of alkylbromide (4.0 equiv) in THF (5 mL) was
added dropwise in 15 min and stirred for another 5 h until most of
magnesium turnings were consumed. The gray solution was cooled to
0 °C followed by addition of a solution of 5-hydroxyvanillin (1.0
equiv) in THF (2 mL) slowly. After being stirred for 15 min at 0 °C,
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dx.doi.org/10.1021/jf302872a | J. Agric. Food Chem. 2012, 60, 8624−8631