Molecules 2018, 23, 2619
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quenched with DMF (0.7 mL, 9 mmol). The resulting mixture was washed with water (50 mL) and
extracted with Et2O (4 30 mL). Organic layers were pooled and washed with water (40 mL) and
×
brine (40 mL), dried over MgSO4, filtrated and concentrated in vacuo. The resulting yellow oil was
submitted to column chromatography over silica gel (petroleum ether/EtOAc 95:5) to yield a yellow
1
solid (0.81 g, 75%). H NMR (CDCl3, 200 MHz):
δ
ppm 10.40 (s, 1H, CHO), 6.58 (s, 2H, ArH), 5.17 (s,
ppm 188.7 (CHO), 159.4 (C), 147.3 (C), 113.7
4H), 3.42 (s, 6H) 2.26 (s, 3H); 13C NMR: (CDCl3, 50 MHz)
δ
(CH), 109.3 (CH), 94.6 (CH), 56.3 (OCH3), 22.5 (CH3); MS m/z: 240(2), 209(2), 195(3), 179(4), 178(10),
165(3), 164(4), 136(2), 77(2), 46(3), 45(100).
Atranol: 1,3-di(methoxymethoxy)-4-methylbenzaldehyde (0.315 g, 1.3 mmol) was dissolved in 30 mL of
MeOH at room temperature under a nitrogen atmosphere. Acetyl chloride was then added dropwise
(60
µl, 0.9 mmol). The mixture was stirred for 20 h and concentrated in vacuo. An aqueous HCl
solution was then added (30 mL at 0.1 M) and the resulting mixture extracted with EtOAc (3
×
150 mL).
Organic layers were pooled and dried over MgSO4, filtrated and concentrated in vacuo. The resulting
light-yellow oil was submitted to column chromatography over silica gel (petroleum ether/EtOAc
1
8:2), and atranol 1 was obtained as a light yellow oil (0.164 g, 90%). H NMR (Acetone-d6, 200 MHz):
δ ppm 10.71 (s, 2H, OH), 10.26 (s, 1H, CHO), 6.25 (s, 2H, ArH), 2.23 (s, 3H). 13C NMR (Acetone-d6,
50 MHz): δ ppm 194.2 (CHO), 163.1 (C), 151.6 (C), 109.3 (C), 108.4 (CH), 22.4 (CH3). MS m/z: 152 (84),
151(100), 134(6), 123(4), 106 (16), 95(9), 77(14), 69 (6), 67(11), 55(12).
5-Methylpyrogallol 1: Atranol (0.152 g, 1 mmol) and sodium percarbonate (0.236 g, 1.5 mmol) were
dissolved in THF/water 3:7 mixture (5 mL). The reaction mixture is then stirred at room temperature
for 2 h. After completion of the reaction, aqueous 0.1 M HCl solution was added (5 mL) and the mixture
extracted with EtOAc (2
×
10 mL). Organic layers were pooled and dried over MgSO4, filtrated and
1
concentrated in vacuo. An orange solid was obtained (0.119 g, 85%). H NMR (Acetone-d6, 200 MHz):
δ
ppm 7.64 (s, 2H, OH), 7.02 (s, 1H, OH), 6.20 (s, 2H, ArH), 2.10 (s, 3H). 13C NMR (Acetone-d6, 50 MHz):
δ
ppm 146.3 (C), 131.0 (C), 129.2 (C), 108.5 (CH), 20.9 (CH3). MS m/z: 140 (100), 139(34), 134 (6), 123(11),
122(19), 121(9), 94 (35), 77(4), 66(37), 65(21), 55(6), 53(17).
Dimer : 5-methylpyrogallol (200 mg, 1.43 mmol) was dissolved in a carbonate aqueous buffer at pH9
2
(20 mM, 65 mL), containing HRP (124 U/mg, 4 mg). The flask was covered with an aluminium foil and
H2O2 (30% aqueous solution) was added at the controlled flow of 0.1 mL/h to reach a final amount
of 2 equiv. The reaction mixture was stirred at room temperature for 6 h followed by the addition of
an aqueous HCl solution (40 mL, 0.1 M) further extracted with EtOAc (3
aqueous phase a white powder of dimer
400 MHz):
13C RMN: (D2O, 100 MHz)
85.7 (C), 77.7 (C), 60.1 (CH), 54.4 (CH), 52.9 (CH), 25.7 (CH3), 23.6 (CH3). MS (ESI): [M
×
70 mL). Evaporation of
and small amounts of salt (0.193 g, 88%). H NMR (D2O,
1
2
δ
ppm 6.37 (t, 1H), 3.97 (d, 1H), 3.37 (s, H), 2.68 (s, 2H), 2.62 (s, H), 2.14 (s, 3H), 1.79 (s, 3H).
ppm 197.2 (C), 178.0 (C), 171.5 (C), 164.1 (C), 127.1 (CH), 88.7 (C), 87.1 (C),
H]− ion
2H + Na]+ at m/z 641. A (20 ◦C, 589 nm) =
δ
−
was observed at m/z 309, [2M
−0.002◦ ± 0.000.
−
H]+ at m/z 619, [2M
−
Acetylated dimer 20: To a solution of dimer
2 (0.100 g, 0.32 mmol) in freshly distilled dichloromethane
(2 mL) were added Et3N (0.28 mL, 2.1 mmol) and Ac2O (0.2 mL, 2.1 mmol). The mixture was stirred
overnight at room temperature under a nitrogen atmosphere. After concentration in vacuo, water
was added (10 mL) and the resulting solution extracted with EtOAc (2
×
10 mL). The organic layers
were pooled, dried over MgSO4, filtrated and concentrated in vacuo. A colourless oil was obtained
1
(0.12 g, 90%). H NMR (CDCl3, 400 MHz):
δ ppm 6.12 (s, 1H), 5.26 (s, 1H), 5.16 (s, 1H), 3.88 (s, 1H),
3.86 (s, 1H), 3.62 (s, 1H), 2.23 (s, 3H), 2.10 (s, 3H), 2.05 (s, 3H), 1.67 (s, 3H). 13C NMR: (CDCl3, 100 MHz)
δ ppm 170.9 (CO), 169.8 (CO), 169.7 (CO), 169.5 (CO), 169.1 (CO), 140.6 (C), 134.3 (C), 120.9 (C), 88.6(C),
87.3(C), 80.9 (C), 77.7 (C), 58.6 (CH), 55.5 (CH), 50.6 (CH), 23.2 (CH3), 20.9 (CH3), 20.7 (CH3), 20.7
(CH3), 20,5 (CH3). MS m/z: 418(1), 376(20), 334(7), 290(2), 273(3), 266(1), 246(2), 231(3), 214(6), 182(23),
175(3), 162(6), 141(28), 140(100), 91(1), 77(2), 69(2), 43(100). HRMS: 419.0950, calculated for [M.H]+