644
Helvetica Chimica Acta – Vol. 93 (2010)
Xanthoangelol (¼(2E)-1-{3-[(2E)-3,7-Dimethylocta-2,6-dien-1-yl]-2,4-dihydroxyphenyl}-3-(4-hy-
droxyphenyl)prop-2-en-1-one; 4). As described for 1, with 13 (0.20 g, 0.4 mmol), MeOH (5 ml), and
conc. HCl soln. (0.2 ml). FC (hexane/AcOEt 4 :1) gave 4 (0.104 g, 75%). Solid. M.p. 142 – 1438. IR
(KBr): 3386, 2921, 1607, 1512, 1444, 1371, 1318, 1237, 1169, 1107, 831, 627. 1H-NMR (CDCl3, 300 MHz):
13.86 (s, 1 H); 7.79 (d, J ¼ 15.3, 1 H); 7.69 (d, J ¼ 9.0, 1 H); 7.48 (d, J ¼ 8.6, 2 H); 7.43 (d, J ¼ 15.3, 1 H);
6.87 (d, J ¼ 8.6, 2 H); 6.44 (d, J ¼ 9.0, 1 H); 5.31 (t, J ¼ 7.2, 1 H); 5.06 (t, J ¼ 6.6, 1 H); 3.48 (d, J ¼ 7.2, 2 H);
2.20 – 1.98 (m, 4 H); 1.83 (s, 3 H); 1.67 (s, 3 H); 1.59 (s, 3 H). 13C-NMR (CDCl3, 75 MHz): 192.5; 163.9;
161.9; 158.5; 144.5; 139.0; 132.0; 130.7; 129.4; 127.3; 123.8; 121.1; 117.8; 116.1; 114.5; 114.0; 108.0; 39.7;
26.4; 25.7; 21.7; 17.7; 16.3. HR-EI-MS: 392.1989 (Mþ, C25H28O4þ ; calc. 392.1988).
3-Geranyl-2,3’,4,4’-tetrahydroxychalcone (¼(2E)-3-(3,4-Dihydroxyphenyl)-1-{3-[(2E)-3,7-dimethyl-
octa-2,6-dien-1-yl]-2,4-dihydroxyphenyl}prop-2-en-1-one; 5). As described for 1, with 14 (0.15 g,
0.2 mmol), MeOH (5 ml), and conc. HCl soln. (0.2 ml). FC (hexane/AcOEt 2 :1) gave 5 (0.061 g,
72%). Solid. M.p. 131 – 1338. IR (KBr): 3424, 2963, 1608, 1554, 1449, 1376, 1276, 1106, 976, 800, 743, 636.
1H-NMR ((D6)acetone, 300 MHz): 7.97 (d, J ¼ 8.7, 1 H); 7.77 (d, J ¼ 15.3, 1 H); 7.68 (d, J ¼ 15.3, 1 H); 7.33
(d, J ¼ 2.0, 1 H); 7.21 (dd, J ¼ 8.4, 2.0, 1 H); 6.90 (d, J ¼ 8.4, 1 H); 6.52 (d, J ¼ 8.7, 1 H); 5.30 (t, J ¼ 7.2,
1 H); 5.06 (t, J ¼ 6.6, 1 H); 3.38 (d, J ¼ 7.2, 2 H); 2.07 – 1.91 (m, 4 H); 1.79 (s, 3 H); 1.59 (s, 3 H); 1.54 (s,
3 H). 13C-NMR ((D6)acetone, 75 MHz): 193.0; 165.2; 162.7; 149.1; 146.4; 145.3; 135.2; 131.6; 130.2;
128.3; 125.1; 123.4; 123.2; 118.5; 116.4; 116.2; 116.0; 114.4; 108.0; 40.5; 27.4; 25.8; 22.2; 17.7; 16.3. HR-EI-
MS: 408.1934 (Mþ, C25H28Oþ5 ; calc. 408.1937).
3-Geranyl-2,4,6-trihydroxyacetophenone (¼1-{3-[(2E)-3,7-Dimethylocta-2,6-dien-1-yl]-2,4,6-trihy-
droxyphenyl}ethanone; 18) [24b]. To a soln. of 2,4,6-trihydroxyacetophenone (17; 0.505 g, 3.0 mmol)
and geranyl bromide (0.652 g, 3.0 mmol) in dry acetone (50 ml) was added anh. K2CO3 (0.830 g,
6.0 mmol). The mixture was refluxed for 24 h. Evaporation of the acetone, addition of 2n HCl (30 ml),
and extraction with AcOEt (3 ꢂ 30 ml), washing with brine (30 ml), drying (MgSO4), and removal of the
solvent followed by FC (hexane/AcOEt 7:1) gave 18 (0.676 g, 74%) as solid material.
1-[3-Geranyl-2-hydroxy-4,6-bis(methoxymethoxy)phenyl]ethanone (¼1-{3-[(2E)-3,7-Dimethylocta-
2,6-dien-1-yl]-2-hydroxy-4,6-bis(methoxymethoxy)phenyl}ethanone; 19). As described for 12, with
i
MOMCl (0.177 g, 2.2 mmol), 18 (0.304 g, 1.0 mmol), Pr2EtN (0.646 g, 5.0 mmol), and dry CH2Cl2
(20 ml). FC (hexane/AcOEt 10 :1) afforded 19 (0.353 g, 90%). Oil. IR (neat): 2916, 1615, 1426, 1372,
1272, 1230, 1153, 1106, 1069, 962, 924, 872, 722. 1H-NMR (CDCl3, 300 MHz): 13.79 (s, 1 H); 6.37 (s, 1 H);
5.23 (s, 2 H); 5.21 (s, 2 H); 5.17 (t, J ¼ 6.9, 1 H); 5.04 (t, J ¼ 6.6, 1 H); 3.49 (s, 3 H); 3.45 (s, 3 H); 3.29 (d,
J ¼ 6.9, 2 H); 2.64 (s, 3 H); 2.06 – 1.90 (m, 4 H); 1.75 (s, 3 H); 1.62 (s, 3 H); 1.54 (s, 3 H). 13C-NMR
(CDCl3, 75 MHz): 203.3; 163.3; 160.6; 158.6; 134.6; 130.9; 124.3; 122.3; 110.4; 106.7; 94.4; 93.7; 91.1; 56.4;
56.1; 39.6; 32.9; 26.6; 25.4; 21.3; 17.4; 15.9. HR-EI-MS: 392.2198 (Mþ, C22H32O6þ ; calc. 392.12199).
(2E)-3-(3,4-Dimethoxyphenyl)-1-[3-geranyl-2-hydroxy-4,6-bis(methoxymethoxy)phenyl]prop-2-en-
1-one (¼(2E)-3-(3,4-Dimethoxyphenyl)-1-{3-[(2E)-3,7-dimethylocta-2,6-dien-1-yl}-2-hydroxy-4,6-(bis-
(methoxymethoxy)phenyl}prop-2-en-1-one; 20). As described for 13, with 19 (0.30 g, 0.8 mmol), EtOH
(20 ml), KOH (0.429 g, 7.6 mmol), and 3,4-dimethoxybenzaldehyde (0.165 g, 1.0 mmol). Workup with
sat. NH4Cl soln. (80 ml), AcOEt (3 ꢂ 80 ml), and brine (30 ml), followed by FC (hexane/AcOEt 10 :1):
20 (0.294 g, 71%). Oil. IR (neat): 2918, 1616, 1512, 1416, 1308, 1261, 1135, 1072, 959, 808, 721. 1H-NMR
(CDCl3, 300 MHz): 7.81 (d, J ¼ 15.6, 1 H); 7.72 (d, J ¼ 15.6, 1 H); 7.16 (d, J ¼ 8.1, 1 H); 7.11 (s, 1 H); 6.85
(d, J ¼ 8.1, 1 H); 6.34 (s, 1 H); 5.25 – 5.24 (m, 3 H); 5.21 (s, 2 H); 5.04 (t, J ¼ 6.6, 1 H); 3.89 (s, 6 H); 3.50 (s,
3 H); 3.45 (s, 3 H); 3.31 (d, J ¼ 6.9, 2 H); 2.08 – 1.90 (m, 4 H); 1.76 (s, 3 H); 1.61 (s, 3 H); 1.54 (s, 3 H).
13C-NMR (CDCl3, 75 MHz): 192.9; 163.7; 160.5; 157.9; 151.0; 149.1; 142.3; 134.7; 131.0; 128.4; 125.5;
124.3; 122.7; 122.3; 112.0; 111.0; 109.9; 107.6; 95.5; 93.8; 92.1; 56.8; 56.1; 55.8; 55.6; 39.7; 26.6; 25.5; 21.5;
17.5; 16.0. HR-FAB-MS: 541.2803 ([M þ H]þ, C31H41O8þ ; calc. 541.2801).
(2E)-3-(3,4-Dimethoxyphenyl)-1-[3-geranyl-2,4,6-trihydroxyphenyl]prop-2-en-1-one (¼(2E)-3-
(3,4-Dimethoxyphenyl)-1-{3-[(2E)-3,7-dimethylocta-2,6-dien-1-yl]-2,4,6-trihydroxyphenyl}prop-2-en-1-
one; 21). As described for 1, with 20 (0.20 g, 0.4 mmol), MeOH (5 ml), and conc. HCl soln. (0.2 ml): 21
(0.115 g, 69%). Oil. IR (neat): 3413, 2931, 1711, 1623, 1514, 1443, 1336, 1261, 1138, 1080, 1024, 980, 848,
813. 1H-NMR (CDCl3, 300 MHz): 7.87(d, J ¼ 15.6, 1 H); 7.73 (d, J ¼ 15.6, 1 H); 7.15 (d, J ¼ 8.1, 1 H); 7.06
(s, 1 H); 6.81 (d, J ¼ 8.1, 1 H); 5.92 (s, 1 H); 5.25 (t, J ¼ 6.9, 1 H); 5.03 (t, J ¼ 6.6, 1 H); 3.87 (s, 3 H); 3.86 (s,
3 H); 3.37 (d, J ¼ 6.9, 2 H); 2.12 – 2.04 (m, 4 H); 1.79 (s, 3 H); 1.64 (s, 3 H); 1.56 (s, 3 H). 13C-NMR