Molecules 2011, 16
8057
2-Methyl-6-(3-methoxy-4-methylphenyl)-heptene (4b). The method was identical to that described for
the preparation of 1 (colorless oil, 93%). IR (film/cm−1): 2,958, 2,922, 1,612, 1,581, 1,508, 1,459,
1,414, 1,256, 1,135, 1,043, 851, 815. 1H-NMR (500 MHz, CDCl3): 1.23 (3H, d, J = 7.0 Hz), 1.51 (3H, s),
1.51–1.65 (2H, m), 1.66 (3H, s), 1.86–1.92 (2H, m), 2.18 (3H, s), 2.63–2.67 (1H, m), 3.82 (3H, s),
5.10 (1H, t, J = 7.1 Hz), 6.65 (1H, d, J = 1.1 Hz), 6.68 (1H, dd, J = 7.55 Hz, J = 1.45 Hz), 7.04 (1H, d,
J = 7.55 Hz). 13C-NMR (125 MHz, CDCl3): 16.0 (CH3), 17.9 (CH3), 22.7 (CH3), 25.9 (CH3),
26.4 (CH2), 38.6 (CH2), 39.7 (CH), 55.4 (CH3), 109.1 (CH), 118.8 (CH), 124.7 (CH), 124.8 (CH),
130.5 (CH), 131.5(C), 146.9 (C), 157.8 (C). ESP-MS: M+H = 233.
2-Methyl-6-(2,5-dimethoxy-4-methylphenyl)-heptene (4c). The method was identical to that described
for the preparation of 1 (94% yield as a colorless oil). 1H-NMR: 1.28 (d, J = 7.2Hz, 3H), 1.56 (s, 3H),
1.57–1.59 (m, 2H), 1.75 (s, 3H), 1.96–2.04 (m, 2H), 2.33 (s, 3H), 3.21–3.26 (m, 1H), 3.87 (s, 3H),
3.88 (s, 3H), 5.22 (t, J = 6.9Hz, 1H), 6.67 (s, 1H), 6.70 (s, 1H). 13C-NMR: 16.0, 17.5, 21.2, 25.6, 26.3,
31.8, 37.3, 56.0, 56.3, 111.6, 112.5, 122.0, 125.0, 126.7, 133.1, 136.8, 157.1. EIMS (m/z): 262, 247,
219, 192, 179, 149, 119, 91. HRMS: required C17H27O2 262.2013, found 262.2009.
Xanthorrhizol (2). To a solution of EtSH (0.8 mL, 10.82 mmol) in anhydrous DMF (35 mL) was added
NaH (60% in mineral oil, 430 mg, 10.82 mmol), then compound 4b (500 mg, 2.15 mmol) in DMF
(2 mL) was added, and the mixture was refluxed for 6 hours. After completion, the mixture was poured
into ice water, and was acidified, and extracted. The extraction was condensed, and the residue was
purified by common column chromatography to give xanthorrhizol (2, 410 mg, 87%). IR (cm−1): 3,392,
1
2,960, 2,922, 1,585, 1,453, 1,256, 1,176, 1,122, 880, 815. H-NMR (500 MHz, CDCl3): 1.18 (3H, d,
J =7.0 Hz), 1.52 (3H, s), 1.51–1.65 (2H, m), 1.66 (3H, s), 1.86–1.92 (2H, m), 2.20 (3H, s), 2.56–2.63
(1H, m), 4.66 (1H, br, s), 5.06–5.09 (1H, m), 6.59 (1H, d, J = 1.5 Hz), 6.60 (1H, dd, J = 7.7 Hz,
J = 1.50 Hz), 7.02 (1H, d, J = 7.7 Hz). 13C-NMR (125 MHz, CDCl3): 15.5 (CH3), 17.8 (CH3),
22.5 (CH3), 25.8 (CH3), 26.3 (CH2), 38.5 (CH2), 39.2 (CH), 113.7 (CH), 119.6 (CH), 120.9 (C),
124.7 (CH), 130.9 (CH), 131.6 (C), 147.4 (C), 153.7 (C). ESP(−)-MS: M−H = 217. HRMS: required
C15H22O2, 218.1671, found 218.1673.
(±)-Curcuhydroquinone (3). To a suspension Mg (1.45 g, 60 mmol) in 10 mL of anhydrous diethyl
ether was added slowly iodomethane (6.35 g, 45 mmol) in anhydrous diethyl ether at room
temperature. After completion, the reaction mixture was refluxed for 1 h and then the mixture was
evaporated in vacuum. The neat compound 4c (393mg, 1.5 mmol) was heated to 180 °C for 15 min,
after cooled to room temperature and 100 mL 1.0 M HCl was added to quench the reaction. The
mixture was extracted EtOAc (3 × 20mL); the combined organic layer was washed with brine and
dried over Na2SO4. After evaporation the residue was purified through column chromatography to give 3
(316 mg, 90%) as a colorless oil. IR (neat): 3,545, 2,966, 2,927, 1,666, 1,615, 1,456, 1,417, 1,377,
1,306, 1,187, 1,003, 875, 833 cm−1. 1H-NMR: 1.20 (d, J = 7.2Hz, 3H), 1.53 (s, 3H), 1.50–1.63 (m, 2H),
1.68 (s, 3H), 1.92–1.95 (m, 2H), 2.17 (s, 3H), 2.94 (m, 1H), 4.65 (br, 1H), 5.15 (br, 1H), 6.56 (br, 1H),
6.71(br, 1H), 7.02 (d, J = 7.9Hz, 1H). 13C-NMR (CDCl3, 300 MHz): 15.4, 17.7, 21.1, 25.7, 26.0, 31.5,
37.4, 113.5, 118.0, 121.8, 124.6, 131.8, 132.1, 146.7, 147.8. MS (EI): 235 (M++1), 234, 217, 191, 177,
164, 151, 137, 124, 107, 95, 77. HRMS: required C15H22O2, 234.1700, found 234.1703.