June 2010
821
(CDCl3, 100 MHz) d: 181.95, 181.86, 147.80, 141.78, 141.36, 139.34,
136.41, 126.77, 52.43, 40.62, 38.34, 34.91, 33.06, 32.59, 27.04, 22.85,
21.49, 21.38, 18.57, 15.33; IR (KBr, cmꢂ1) 3440, 2945, 2866, 2779, 1676,
1639, 1595, 1522, 1466, 1379, 1323, 1304, 1292, 1173, 1093, 920, 839,
808, 690, 604, 536; MS (EI) m/z (%): 300 (Mꢃ2, 16), 298 (Mꢃ, 11), 270
(76), 255 (100), 241 (20), 227 (40), 213 (24), 199 (45), 185 (43), 171 (27),
157 (34), 143 (18), 128 (20), 115 (13), 91 (9), 83 (8), 69 (11), 55 (8); HR-
MS (EI) m/z: 298.1942 (Calcd for C20H26O2 298.1933). Taxodone (21): or-
dissolved in tetrahydrofuran (THF) (25 ml). To the solution, LiAlH4
(433.4 mg, 11.4 mmol) was added slowly with cooling in ice-water bath. The
reaction mixture was stirred for 7 h at ambient temperature under Ar. The re-
action was quenched by slow addition of EtOAc and 1 M HCl with cooling.
The mixture was extracted with hexane and the organic layer was washed
with 1 M HCl, dried over MgSO4, and concentrated. The residue was chro-
matographed on silica gel with hexane–EtOAc (5 : 1) to give 17 (714.9 mg,
1
52%) as a colorless oil: H-NMR (CDCl3, 400 MHz) d: 6.44 (1H, s), 5.63
1
ange solid, mp 139—142 °C: H-NMR (CDCl3, 400 MHz) d: 7.49 (1H, s),
(1H, br), 4.60 (1H, br), 3.09—3.01 (1H, m), 2.97 (1H, sept, Jꢁ6.8 Hz),
2.83—2.75 (2H, m), 1.85—1.67 (2H, m), 1.62—1.41 (4H, m), 1.33 (3H, s),
1.40—1.28 (2H, m), 1.25 (3H, d, Jꢁ6.8 Hz), 1.23 (3H, d, Jꢁ6.8 Hz), 0.95
(3H, s), 0.92 (3H, s); 13C-NMR (CDCl3, 100 MHz) d: 142.85, 138.17,
133.12, 131.41, 129.71, 117.29, 52.81, 41.37, 39.17, 36.74, 33.69, 32.45,
27.26, 22.72, 22.47, 22.11, 20.24, 19.35, 19.29; IR (NaCl, cmꢂ1) 3489,
2956, 2918, 2864, 2841, 1705, 1620, 1568, 1493, 1475, 1462, 1435, 1387,
1367, 1325, 1146, 1095, 1045, 1011, 993, 972, 895, 877, 858, 831, 816,
771, 561, 519, 501; MS (EI) m/z (%): 302 (Mꢃ, 100), 287 (65), 285 (17),
272 (13), 257 (16), 245 (14), 231 (34), 229 (23), 217 (75), 205 (77), 191
(93); HR-MS (EI) m/z: 302.2252 (Calcd for C20H30O2 302.2246).
6.81 (1H, s), 6.55 (1H, d, Jꢁ2.4 Hz), 4.69 (1H, m, Jꢁ2.4 Hz), 3.06 (1H,
sept, Jꢁ6.8 Hz), 2.91 (1H, m), 1.72—1.51 (6H, m), 1.44 (1H, m), 1.32 (1H,
m), 1.22 (3H, s), 1.21 (3H, s), 1.15 (3H, s), 1.15 (3H, d, Jꢁ6.8 Hz), 1.14
(3H, d, Jꢁ6.8 Hz); 13C-NMR (CDCl3, 100 MHz) d: 181.68, 149.15, 143.38,
141.94, 135.70, 130.40, 126.21, 70.01, 57.97, 43.17, 40.70, 37.59, 36.68,
34.06, 26.70, 22.80, 21.71, 21.39, 20.79, 18.80; IR (KBr, cmꢂ1): 3437, 3319,
2960, 2879, 1610, 1558, 1448, 1354, 1255, 1205, 1155, 1099, 1057, 976,
914, 636, 704, 575; MS (EI) m/z (rel. int. %): 316 (Mꢃ, 100), 298 (30), 283
(27), 273 (31), 255 (20), 245 (34), 220 (67), 219 (63), 205 (47), 191 (28),
177 (30), 173 (22), 161 (18), 129 (13), 128 (10), 115 (9), 83 (9), 69 (16), 55
(12); HR-MS (EI) m/z: 316.2038 (Calcd for C20H28O3 300.2038).
8,12-Abietadiene-11,12-dione (18) To a solution of diol 17 (402.0 mg,
1.33 mmol) in CH2Cl2 (10 ml) was added Ag2O (568.2 mg, 2.45 mmol), and
the mixture was stirred for 40 min at ambient temperature under Ar. The
mixture was filtered through a pad of Celite and the filtrate was concentrated
to give 18 (377.9 mg, 1.26 mmol, 95%) as brown crystals, mp 107—109 °C:
1H-NMR (CDCl3, 400 MHz) d: 6.40 (1H, s), 2.90 (1H, sept, Jꢁ6.8 Hz),
2.78—2.66 (1H, m), 2.58—2.34 (2H, m), 1.91—1.80 (1H, m), 1.76—1.33
(4H, m), 1.31—0.97 (3H, m), 1.22 (3H, s), 1.09 (3H, d, Jꢁ6.8 Hz), 1.08
(3H, d, Jꢁ6.8 Hz), 0.93 (3H, s), 0.88 (3H, s); 13C-NMR (CDCl3, 100 MHz)
d: 181.19, 180.21, 147.88, 146.57, 144.81, 137.82, 51.23, 41.48, 37.95,
35.96, 33.75, 33.41, 33.34, 26.81, 21.65, 21.38, 21.33, 19.92, 18.79, 18.00;
IR (KBr, cmꢂ1) 3442, 3313, 3288, 2966, 2922, 2873, 1647, 1572, 1464,
1390, 1313, 1269, 1174, 1101, 1043, 974, 904, 831, 754, 694, 654, 584,
488, 415, 380; MS (EI) m/z (%): 300 (Mꢃ, 100), 285 (72), 257 (27), 244
(23), 229 (79), 215 (51), 204 (60), 189 (32), 187 (20), 171 (18), 149 (46),
129 (12), 95 (12), 81 (25), 69 (12), 55 (14); HR-MS (EI) m/z: 300.2069
(Calcd for C20H28O2 300.2089).
6-Oxo-abieta-8,11,13-triene-11,12-diol (22) A solution of 21 (18.4 mg,
0.058 mmol) in MeOH (8 ml) was acidified with one drop of 12 M HCl and
heated at 50 °C for 15 min. The mixture was concentrated in vacuo to give
22 (18.4 mg, 0.058 mmol, quantitative yield) as colorless solids: 1H-NMR
(CDCl3, 400 MHz) d: 6.40 (1H, s), 5.93 (1H, br), 5.02 (1H, br), 3.70 (1H, d,
Jꢁ20.0 Hz), 3.37 (1H, d, Jꢁ20.0 Hz), 3.24—3.16 (1H, m), 3.03 (1H, sept,
Jꢁ6.8 Hz), 2.65 (1H, s), 1.81—1.53 (5H, m), 1.35 (3H, s), 1.25 (3H, s), 1.23
(3H, d, Jꢁ6.8 Hz), 1.08 (3H, d, Jꢁ6.8 Hz), 1.02 (3H, s); 13C-NMR (CDCl3,
100 MHz) d: 211.06, 142.80, 138.80, 132.59, 131.73, 126.10, 116.67, 63.26,
46.43, 44.46, 42.41, 37.33, 32.90, 32.72, 27.21, 22.71, 22.45, 21.90, 21.28,
18.97; MS (EI) m/z (rel. int. %): 316 (Mꢃ, 100), 301 (60), 283 (17), 273
(86), 259 (14), 245 (19), 231 (57), 217 (28), 203 (16), 189 (13), 175 (9), 161
(8), 149 (8), 129 (6), 128 (6), 91 (7), 69 (17), 55 (6).
Taxodione (2)
A solution of diol 22 (18.4 mg, 0.058 mmol) in
hexane–EtOAc (10 : 1, 2 ml) was poured on 4 g of silica gel. The mixture
was allowed in air for 72 h at ambient temperature. The silica gel was ex-
tracted with hexane–EtOAc and the solution was concentrated. The residue
was chromatographed on silica gel with hexane–EtOAc (10 : 1) to give 2
(19.7 mg, quantitative yield) as a yellow oil: 1H-NMR (CDCl3, 400 MHz) d:
7.57 (1H, s), 6.88 (1H, s), 6.21 (1H, s), 3.08 (1H, sept, Jꢁ6.8 Hz), 2.94 (1H,
m), 2.60 (1H, s), 1.81—1.53 (4H, m), 1.41 (1H, m) 1.27 (6H, s), 1.18 (3H, d,
Jꢁ6.8 Hz), 1.16 (3H, d, Jꢁ6.8 Hz), 1.12 (3H, s); 13C-NMR (CDCl3,
100 MHz) d: 201.08, 181.70, 145.32, 144.97, 139.90, 136.15, 133.99,
125.62, 62.96, 42.87, 42.54, 36.99, 33.25, 32.82, 27.13, 22.11, 21.82, 21.64,
21.22, 18.53; IR (NaCl, cmꢂ1): 3323, 2929, 2873, 1728, 1674, 1620, 1460,
1425, 1352, 1292, 1242, 1151, 1053, 980, 914, 858, 810, 731, 652, 579; MS
(EI) m/z (rel. int. %): 314 (Mꢃ, 100), 299 (20), 286 (55), 271 (58), 269 (43),
245 (38), 229 (55), 215 (22), 199 (36), 187 (16), 185 (15), 171 (14), 157
(12), 128 (11), 109 (10), 91 (6), 69 (10), 55 (6); HR-MS (EI) m/z 314.1899
(Calcd for C20H26O3 314.1882).
Abietaquinone Methide (1) and Abieta-6,8,11,13-tetraene-11,12-diol
(19) o-Quinone 18 (315.4 mg, 1.05 mmol) was dissolved in CHCl3 (15 ml)
and the solution was refluxed for 72 h under Ar. Quinone methide 1 (63%)
and diol 19 were observed by 1H-NMR analysis in a ratio of about 2 : 1. The
mixture was separated by column chromatography on silica gel with
hexane–EtOAc (8 : 1) to give 1 (198.5 mg, 63%) and 19 (88.3 mg, 28%).
Since diol 19 is unstable, only the 1H-NMR could be measured. Abi-
1
etaquinone methide (1): reddish crystals, mp 65—70 °C: H-NMR (CDCl3,
400 MHz) d: 7.47 (1H, s), 6.81 (1H, dd, Jꢁ6.8, 4.4 Hz), 6.78 (1H, s), 3.07
(1H, sept, Jꢁ6.8 Hz), 3.00 (1H, m), 2.58 (1H, ddd, Jꢁ20.9, 6.8, 3.9 Hz),
2.40 (1H, ddd, Jꢁ20.9, 12.2, 2.9 Hz), 1.72—1.51 (4H, m), 1.46 (1H, m),
1.27 (1H, dt, Jꢁ13.2, 3.4 Hz), 1.18 (3H, s), 1.15 (3H, d, Jꢁ6.8 Hz), 1.14
(3H, d, Jꢁ6.8 Hz), 0.98 (3H, s), 0.93 (3H, s); 13C-NMR (CDCl3, 150 MHz)
d: 181.23, 149.01, 143.70, 140.31, 135.99, 131.45, 127.15, 50.37, 41.60,
38.50, 36.65, 33.41, 33.18, 26.52, 25.71, 21.97, 21.70, 21.36, 18.81, 18.36;
IR (KBr, cmꢂ1): 3527, 3439, 3309, 2956, 2920, 2870, 1608, 1560, 1462,
1439, 1389, 1358, 1257, 1215, 1147, 1111, 1049, 1016, 984, 935, 839, 810,
752, 702, 638, 579, 561, 542, 523; MS (EI) m/z (rel. int. %): 300 (Mꢃ, 100),
285 (47), 271 (7), 257 (24), 244 (18), 229 (65), 215 (33), 204 (53), 189 (21),
187 (14), 171 (11), 157 (9), 141 (8), 129 (8), 128 (7), 84 (28), 69 (6), 55 (6);
HR-MS (EI) m/z: 300.2065 (Calcd for C20H28O2 300.2089). Abieta-
6,8,11,13-tetraene-11,12-diol (19): colorless oil: 1H-NMR (CDCl3,
400 MHz) d: 6.50 (1H, s), 6.43 (1H, dd, Jꢁ9.3, 2.9 Hz), 5.85 (1H, dd,
Jꢁ9.3, 2.9 Hz), 5.59 (1H, br), 5.13 (1H, br), 2.90 (1H, sept, Jꢁ6.8 Hz), 2.79
(1H, m), 2.22 (1H, t, Jꢁ2.9 Hz), 1.80—1.20 (5H, m), 1.26 (3H, d,
Jꢁ6.8 Hz), 1.22 (3H, d, Jꢁ6.8 Hz), 1.15 (3H, s), 1.03 (3H, s), 0.97 (3H, s).
Abieta-6,8,13-triene-11,12-dione (20) and Taxodone (21) To a solu-
tion of 19 (88.3 mg, 0.294 mmol) in CH2Cl2 (5 ml) was added Ag2O
(133.3 mg, 0.575 mmol), and the mixture was stirred for 23.5 h at 20 °C
under Ar. The mixture was filtered through a pad of Celite and the filtrate
was concentrated. The residue was chromatographed on silica gel with
hexane–EtOAc (10 : 1) to give 20 (44.0 mg, 50%), 21 (18.4 mg, 20%), and a
mixture (7.7 mg, ca. 9%) of 3, 21 and 1. Abieta-6,8,13-triene-11,12-dione
(20): brown crystals, mp 120—122 °C: 1H-NMR (CDCl3, 400 MHz) d: 6.57
(1H, d, Jꢁ0.98 Hz), 6.53 (1H, dd, Jꢁ9.3, 2.9 Hz), 6.23 (1H, dd, Jꢁ9.3,
2.9 Hz), 2.93 (1H, double sept, Jꢁ6.8, 0.98 Hz), 2.85 (1H, m), 2.12 (1H, t,
Jꢁ2.9 Hz), 1.73—1.54 (2H, m), 1.49 (1H, m), 1.34—1.20 (2H, m) 1.12
(3H,s), 1.10 (3H, s), 1.01 (3H, s), 1.00 (3H, s), 0.98 (3H, s); 13C-NMR
15-Deoxyfuerstione (3) A solution of 20 (37.0 mg, 0.124 mmol) in
CHCl3 (10 ml) was refluxed for 44 h under Ar. The reaction mixture was
concentrated to give a residue constituted of 3 and 20 in a ratio of 2 : 1 by
1
the H-NMR analysis. The residue was chromatographed on silica gel with
1
hexane–EtOAc (10 : 1) to give 3 (16.2 mg, 44%) as a reddish oil: H-NMR
(CDCl3, 400 MHz) d: 7.74 (1H, s), 6.93 (1H, s), 6.75 (1H, d, Jꢁ6.8 Hz),
6.36 (1H, d, Jꢁ6.8 Hz), 3.31 (1H, m), 3.17 (1H, sept, Jꢁ6.8 Hz), 2.01—1.88
(1H, m), 1.68—1.58 (3H, m), 1.55—1.36 (1H, m), 1.57 (3H, s), 1.30 (3H,
s), 1.23 (3H, s), 1.19 (3H, d, Jꢁ6.8 Hz), 1.18 (3H, d, Jꢁ6.8 Hz); 13C-NMR
(CDCl3, 100 MHz) d: 178.18, 167.91, 146.23, 141.29, 138.97, 133.02,
128.31, 127.21, 118.08, 43.31, 40.88, 37.99, 34.23, 32.92, 29.95, 26.87,
24.64, 21.89, 21.67, 18.61; IR (NaCl, cmꢂ1): 3284, 2958, 2931, 2875, 1728,
1672, 1595, 1518, 1456, 1356, 1265, 1215, 1165, 1109, 1055, 993, 893,
839, 806, 729, 656; MS (EI) m/z (rel. int. %): 298 (Mꢃ, 84), 283 (19), 255
(6), 242 (39), 229 (100), 227 (47), 201 (18), 185 (12), 165 (13), 153 (7), 141
(10), 128 (7), 115 (6), 84 (12); HR-MS (EI) m/z: 298.1898 (Calcd for
C20H26O2 298.1933).
11,12-Diacetoxyabieta-8,11,13-triene (4) Diol 17 (96.9 mg, 0.320
mmol) was dissolved in pyridine (1 ml) and Ac2O (0.5 ml) and the solu-
tion was stirred for 5 h under Ar. The reaction was quenched with 1 M HCl
and the whole was extracted with EtOAc. The organic layer was washed
with 1 M HCl, saturated aqueous NaHCO3, brine, dried over MgSO4 and
concentrated. The residue was chromatographed on silica gel column with
hexane–EtOAc (5 : 1) to give 4 (117.0 mg, 95%) as colorless crystals, mp