Molecules 2018, 23, 3057
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OCHBO), 6.57 (1H, dd, J = 8.0, 1.9 Hz, 6 -H), 6.59 (1H, dd, J = 8.2, 1.8 Hz, 6 -H), 6.64 (1H, d, J = 1.8 Hz,
200-H), 6.69 (1H, d, J = 1.9 Hz, 200-H), 6.71 (1H, d, J = 8.0 Hz, 500-H), 6.75 (1H, d, J = 8.2 Hz, 50-H),
7.25–7.30 (1H, m, 4000-H), 7.32–7.37 (2H, m, 3000-H), 7.38–7.43 (2H, m, 2000-H). δC (100 MHz; CDCl3) 37.4
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(C-7 ), 38.5 (C-7 ), 41.9 (NCHCDCH2O), 46.3 (NCHABCH2O), 46.4 (C-2), 48.8 (C-3), 56.2 (3 -OCH3), 66.3
(NCH2CHABO), 66.9 (NCH2CHCDO), 71.2 (C-7000), 100.9 (OCH2O), 108.1 (C-500), 109.6 (C-200), 113.2
(C-20), 114.5 (C-50), 116.7 (C-5), 121.0 (C-60), 122.1 (C-600), 127.3 (C-2000), 127.9 (C-4000), 128.6 (C-3000),
133.1 (C-10) 133.6 (C-100), 137.3 (C-1000), 139.2 (C-4), 145.9 (C-400), 146.7 (C-40), 147.6 (C-300), 149.7 (C-30),
172.6 (C-1). IR: νMAX (film)/cm−1; 2920, 1630, 1489, 1231, 1114, 1034, 913, 729. HRMS (ESI+) Found
[M + Na]+ 552.2354; C32H35NNaO6 requires 552.2357.
(3R*,4R*)-3-(30,40-Methylenedioxybenzyl)-4-(300,400-dimethoxybenzyl)-5-(hydroxymethyl)dihydrofuran-2(3H)-
one (4ab). Using general procedure B: Amide 35ab (0.38 g, 0.84 mmol) in tBuOH/H2O and a reaction
time of 3 days. The crude product was purified by column chromatography (1:1 hexanes, ethyl acetate)
to give the title compound 4ab (180 mg, 54%) as a white foam. Rf = 0.50 (19:1 CH2Cl2, methanol). δH
(400 MHz; CDCl3) 1.79 (1H, t, J = 6.4 Hz, 6-OH), 2.36–2.44 (1H, m, 4-H), 2.51 (1H, dd, J = 13.7, 7.9 Hz,
700-HA), 2.58 (1H, dd, J = 13.7, 6.6 Hz, 700-HB), 2.680(1H, ddd, J = 9.3, 7.0, 5.5 Hz, 3-H), 2.85 (1H, dd, J =
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14.0, 7.0 Hz, 7 -HA), 2.92 (1H, dd, J = 14.0, 5.5 Hz, 7 -HB), 3.15 (1H, ddd, J = 12.5, 6.4, 5.1 Hz, 6-HA), 3.54
(1H, ddd, J = 12.5, 6.4, 2.5 Hz, 6-HB), 3.83 (3H, s, 300-OCH3), 3.85 (3H, s, 400-OCH3), 4.19 (1H, ddd, J =
8.0, 5.1, 2.5 Hz, 5-H), 5.92 (1H, d, J = 1.5 Hz, OCHAHBO), 5.93 (1H, d, J = 1.5 Hz, OCHAHBO), 6.47 (1H,
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d, J = 2.0 Hz, 2 -H), 6.57–6.60 (2H, m, 6 and 6 -H), 6.61 (1H, d, J = 1.5 Hz, 2 -H), 6.71 (1H, d, J = 7.8 Hz,
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5 -H), 6.77 (1H, d, J = 8.1 Hz, 5 -H). δC (100 MHz; CDCl3) 35.3 (C-7 ), 38.7 (C-7 ), 41.6 (C-4), 47.6 (C-3),
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56.0 (3 -OCH3, 4 -OCH3), 63.2 (C-6), 84.1 (C-5), 101.2 (OCH2O), 108.3 (C-5 ), 109.7 (C-2 ), 111.4 (C-5 ),
112.0 (C-200), 121.0 (C-600), 122.5 (C-60), 130.3 (C-100), 131.6 (C-10), 146.6 (C-40), 148.0 (C-400), 148.1 (C-30),
149.3 (C-300), 177.7 (C-2). IR: νMAX (film)/cm−1; 3496 (broad), 2936, 2254, 1760, 1515, 1489, 1442, 1239,
1025, 909, 809, 766. HRMS (ESI+) Found [M + Na]+ 423.1427; C22H24NaO7 requires 423.1414.
(3R*,4R*)-3,4-bis(30,40-Dimethoxybenzyl)-5-(hydroxymethyl)dihydrofuran-2(3H)-one (4aa). Using general
procedure B: Amide 35aa (0.29 g, 0.61 mmol), in tBuOH/H2O and a reaction time of 6 days. The crude
product was purified by flash chromatography (1:1 hexanes, ethyl acetate) to give the title compound
4aa (0.18 g, 70%) as a colourless oil. Rf = 0.32 (19:1 CH2Cl2, methanol). δH (400 MHz; CDCl3) 2.39–2.44
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(1H, m, 4-H), 2.53 (1H, dd, J = 13.7, 7.3 Hz, 7 -HA), 2.58 (1H, dd, J = 13.7, 6.5 Hz, 7 -HB), 2.64 (1H, br s,
6-OH), 2.71 (1H, ddd, J = 9.3, 6.7, 5.7 Hz, 3-H), 2.88 (1H, dd, J = 14.0, 6.7 Hz, 70-HA), 2.94 (1H, dd, J =
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14.0, 5.5 Hz, 7 -HB), 3.16 (1H, dd, J = 12.6, 4.9 Hz, 6-HA), 3.53 (1H, dd, J = 12.6, 2.4 Hz, 6-HB), 3.81, 3.83,
3.84 (12H, s, 30, 40, 300, 400-OCH3), 4.15 (1H, ddd, J = 8.0, 4.9, 2.4 Hz, 5-H), 6.49 (1H, d, J = 1.9 Hz, 200-H),
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6.57 (1H, dd, J = 8.1, 1.9 Hz, 6 -H), 6.66–6.68 (2H, m, 2 , 6 -H), 6.73–6.80 (2H, m, 5 , 5 -H). δC (100 MHz;
CDCl3) 35.0 (C-70), 38.5 (C-700), 41.6 (C-4), 47.5 (C-3), 55.8 (30, 40, 300, 400-OCH3), 62.9 (C-6), 84.0 (C-5),
111.2, 111.4 (C-50, 500), 112.1 (C-200), 112.6 (C-20), 120.9 (C-600), 121.4 (C-60), 130.4 (C-10, 100), 147.9 (C-40,
400), 149.0 (C-30, 300), 178.0 (C-2). IR: νMAX (film)/cm−1; 3505 (br), 2938, 1761, 1591, 1514, 1465, 1259,
1156, 1025, 910, 808, 766, 647. HRMS (ESI+) Found [M + H]+ 417.1909; C23H29O7 requires 417.1908.
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(3R*,4R*)-3-(3 ,4 ,5 -Trimethoxybenzyl)-4-(3 ,4 -dimethoxybenzyl)-5-(hydroxymethyl)dihydrofuran-2(3H)-one
4ac). Using general procedure B: Amide 35ac (0.45 g, 0.90 mmol) in tBuOH/H2O/THF and a reaction
(
time of 3 days. The crude product was purified by column chromatography (1:1 hexanes, ethyl acetate)
to give the title compound 4ac (0.17 g, 42%) as a pale-yellow solid.
Rf = 0.31 (19:1 CH2Cl2, methanol). Melting point: 141–142 ◦C. δH (400 MHz; CDCl3) 1.68 (1H, t, J =
6.5 Hz, 6-OH), 2.38–2.46 (1H, m, 4-H), 2.55 (1H, dd, J = 13.8, 8.2 Hz, 700-HA), 2.65 (1H, dd, J = 13.8, 5.9
Hz, 700-HB), 2.72 (1H, ddd, J = 9.7, 6.3, 5.7 Hz, 3-H), 2.90 (1H, dd, J = 14.0, 6.3 Hz, 70-HA), 2.95 (1H, dd,
J = 14.0, 5.7 Hz, 70-HB), 3.15 (1H, ddd, J = 12.4, 5.1, 5.4 Hz, 6-HA), 3.54 (1H, ddd, J = 12.4, 6.5, 2.5 Hz,
6-HB), 3.82 (6H, s, 40, 300-OCH3), 3.83 (6H, s, 30-OCH3), 3.85 (3H, s, 400-OCH3), 4.20 (1H, ddd, J = 8.2,
5.1, 2.5 Hz, 5-H), 6.38 (2H, s, 20-H), 6.49 (1H, d, J = 2.0 Hz, 200-H), 6.58 (1H, dd, J = 8.1, 2.0 Hz, 600-H),
6.76 (1H, d, J = 8.1 Hz, 500-H). δC (100 MHz; CDCl3) 35.7 (C-70), 38.6 (C-700), 41.8 (C-4), 47.7 (C-3), 56.0,