1
60
M. Maitrejean et al. / Bioorg. Med. Chem. Lett. 10 (2000) 157±160
+
8
. Di Pietro, A.; Dayan, G.; Conseil, G.; Steinfels, E.; Krell,
Compound 4. EI±MS (70 ev) m/z (rel. int.): 548 [M ] (16), 531
(25), 530 (54), 528 (17), 513 (29), 487 (24), 476 (16), 475 (39),
412 (13), 411 (49), 409 (23), 395 (24), 393 (13), 371 (18), 370
(66.2), 368 (27), 355 (23), 354 (27), 353 (80), 328 (17), 327 (64),
316 (39), 315 (100), 180 (36), 164 (23), 162 (33), 150 (35), 147
(22), 139 (17), 138 (21), 137 (83), 135 (29), 124 (70), 123 (29),
110 (63), 109 (57), 91 (26), 81 (27), 78 (21), 77 (28), 65 (18), 64
(22), 63 (18), 56 (40), 55 (26), 53 (18), 51 (23). HRMS (EI):
calculated for C H O : 548.1682. Found: 548.1691.
T.; Trompier, D.; Baubichon-Cortay, H.; Jault, J.-M. Braz. J.
Med. Biol. Res. 1999, 32, 925.
9
. Daskiewicz, J.-B.; Comte, G.; Barron, D.; Di Pietro, A.;
Thomasson, F. Tetrahedron Lett. 1999, 40, 7095.
0. Bois, F.; Boumendjel, A.; Mariotte, A.-M.; Conseil, G.; Di
Pietro, A. Bioorg. Med. Chem. 1999, 7, 2691.
1. Oxidation of silybin. To a solution of 5 g silybin 2 in 250
mL glacial AcOH were added 50 g of freshly fused KOAc. The
suspension was cooled (ice bath) and a solution of 5 g I in 250
1
1
30
28 10
+
2
Compound 5. EI±MS (70 ev) m/z (rel. int.): 548 [M ] (2.7),
531 (2.4), 530 (3.9), 395 (3.3), 370 (8.4), 355 (8.7), 332 (9.2),
314 (13), 194 (22.2), 180 (81), 139 (43), 137 (100), 131 (15.9),
124 (51), 119 (25), 110 (12), 109 (15), 91 (36), 79 (11), 77 (21),
mL AcOH was added dropwise under stirring. After complete
addition of the iodine solution the medium was re¯uxed for
4
.5 h. The reaction was stopped by addition of 250 mL iced
O, followed by solid Na SO (stirring) until fading of the
H
2
2
3
28 10
65 (17), 55 (22). HRMS (EI): calculated for C30H O ,
colour. The medium was extracted with EtOAc and the extract
concentrated to dryness. The residue was taken in 250 mL of
ethanolic HCl (6% v/v) and re¯uxed for 40 min. Water dilu-
tion of the reaction medium, followed by extraction with
EtOAc and concentration of the organic layer yielded 4.45 g of
pure dehydrosilybin 3.
548.1682. Found: 548.1681. Elemental analysis: calculated for
C H O , 2H O: C, 61.60; H, 5.51. Found: C, 61.90; H, 5.45.
30
28 10
2
13. Geranylation of dehydrosilybin. 1 g of 3 and 0.5 g tetra-
ethylammonium iodide was dissolved in 40 mL of 20% aq
tetraethylammonium hydroxide. 500 mL of geranyl bromide
were added under argon and the reaction was allowed to pro-
ceed for 60 min. The reaction was stopped by addition of 150
mL 1 M aq HCl and extracted with EtOAc. After concentra-
tion of the organic layer, the residue was puri®ed by MPLC on
+
Compound 3. EI±MS (70 ev) m/z (rel. int.): 480 [M ] (0.7),
4
(
1
62 (0.5), 343 (1), 322 (2), 302 (6), 284 (4), 283 (3), 270 (2), 205
2), 181 (11), 180 (77), 178 (16), 164 (29), 162 (11), 152 (14),
51 (17), 150 (47), 149 (17), 147 (18), 142 (11), 138 (18), 137
C18 using a gradient of MeOH in H O as solvent. This yielded
2
(
(
100), 136 (9), 135 (39), 133 (6), 131 (19), 126 (6), 125 (7), 124
60), 122 (11), 119 (23), 110 (21), 109 (37), 107 (19), 103 (16),
®ve fractions A±E. Fraction D was puri®ed by gel ®ltration on
1
Sephadex LH-20 using MeOH as solvent, followed by
9
(
1 (32), 81 (14), 79 (11), 77 (28), 65 (16), 63 (12), 55 (22), 51
17). HRMS (EI): calculated for C H O : 480.1056. Found:
3
MPLC on diol-bonded silica using 1% i-PrOH in CHCl as
solvent. This yielded 14 mg of 6-geranyl dehydrosilybin 6
(1%). Fraction B was puri®ed by gel ®ltration on Sephadex1
LH-20 using MeOH as solvent, followed by MPLC on diol-
bonded silica using 10% i-PrOH in CHCl3 as solvent. This
yielded 60 mg of 8-geranyl dehydrosilybin 7 (5%).
2
5
20 10
480.1041. Elemental analysis: calculated for
1.2H O: C, 59.80; H, 4.49. Found: C, 59.67; H, 4.46.
12. Prenylation of dehydrosilybin. 1 g of 3 is dissolved in 140
25 20 10
C H O ,
2
mL of 10% aq tetramethylammonium hydroxide. After addi-
tion of 0.5 g tetraethylammonium iodide, the solution was
placed in an ice bath. 300 mL of prenyl bromide were added
under argon and the reaction was allowed to proceed for 10
min. The reaction was stopped by addition of 100 mL 1 M aq
HCl and extracted with EtOAc. After concentration of the
organic layer, the residue was puri®ed by MPLC on C18 using
36 10
Compound 6. Elemental analysis: calculated for C35H O :
C, 70.06; H, 7.17. Found: C, 69.74; H, 7.44.
14. Comte, G.; Daskiewicz, J.-B.; Barron, D.; Bayet, C.; Con-
seil, G.; Viornery-Vanier, A.; Dumontet, C.; Di Pietro, A. J.
Med. Chem., submitted for publication.
15. Gruol, D.; Zee, M. C.; Trotter, J.; Bourgeois, S. Cancer
Res. 1994, 54, 3088.
a gradient of MeOH in H O as solvent. This yielded three
2
fractions A, B and C. Fraction B, containing the prenyl deriva-
1
16. Lecureur, V.; Fardel, O.; Guillouzo, A. FEBS Lett. 1994,
355, 187.
tives was further puri®ed by gel ®ltration on Sephadex LH-20
using MeOH as solvent. Yielding 21 mg of 6-prenyl dehydro-
silybin 4 (2%) and 18 mg of 8-prenyl dehydrosilybin 5 (1.5%).