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Y. Todoroki et al. / Bioorg. Med. Chem. 12 (2004) 363–370
resulting mixture was extracted with EtOAc (4 mL Â 8).
The organic layer was washed with H2O, dried over
Na2SO4 and concentrated. The crude oil was dissolved
in THF (0.5 mL), and then AcOH (1.5 mL) and H2O
(0.5 mL) were added. The mixture was stirred for 17 h at
room temperature, H2O was added, and the solution
was extracted with EtOAc (7 mL Â 5). The organic layer
was washed with 1 M NaOH and H2O, dried over
Na2SO4 and concentrated. Column chromatography
with CH2Cl2–acetone (9:1–4:1) gave the enone alcohol
(33 mg) as a colorless oil. MnO2 (activated, 0.27 g) was
added to a solution of the enone alcohol (33 mg) in
CH2Cl2 (15 mL), and stirred for 2 h at room tempera-
ture. The reaction mixture was filtered, and the resulting
cake of MnO2 was washed with CH2Cl2, acetone and
MeOH. After being concentrated, the residual oil was
purified by column chromatography with CH2Cl2–ace-
tone (9:1–4:1) to obtain 4 (30 mg, 54% yield) as a col-
(CycloABA) and 17.1 mg of (À)-enantiomer, as white
amorphous powders with optical purities of 99.8 and
99.7%, respectively, measured by HPLC on the same
column. The optical rotation and CD data were con-
sistent with those reported previously.19
3.1.8. ABA, PA, and DPA. ABA (natural type) was a
gift from Toray Industries Inc., Tokyo, Japan. PA34 and
DPA35 were prepared as reported previously.
3.1.9. ABA-GE tetraacetate. Acetobromo-a-d-glucose
(20 mg, 48 mmol) and Ag2CO3 (40 mg, 150 mmol) were
added to a solution of ABA (10 mg, 38 mmol) in ether
(4 mL) at room temperature, and stirred for 5 h under
Ar. Afterwards, ether (30 mL) was added, the mixture
was washed with brine, dried over Na2SO4, and con-
centrated. The residual oil was purified by column
chromatography with hexane–EtOAc (9:1–2:3) and by
using HPLC with an ODS column (AQ 311, 150 Â
20 mm, YMC; solvent, 60% MeOH in H2O; flow rate,
9.9 mL minÀ1; detection, 254 nm) to obtain ABA-GE
tetraacetate (0.54 mg, 2% yield) as a white amorphous
1
orless oil. H NMR: d 1.13 (1H, dd, J=8.9 and 4.3 Hz,
H-80), 1.21 (3H, s, H3-90), 1.25 (1H, dd, J=4.3 and
4.3 Hz, H-80), 1.82 (3H, d, J=1.3 Hz, H3-70), 1.95 (1H,
ddd, J=8.9, 4.3 and 1.7 Hz, H-50), 2.29 (3H, s, H3-1),
5.68 (1H, dq, J=1.7 and 1.3 Hz, H-30), 6.49 (2H, s, H-3
and H-4); EIMS m/z (rel. int.): 220 [M]+ (13), 205 [M-
Me]+ (23), 202 [M-H2O]+ (15), 192 (17), 177 (100), 162
(59), 159 (55), 149 (70), 135 (62), 123 (59), 109 (78);
HREIMS: [M]+ at m/z 220.1082 (calcd for C13H16O3,
m/z 220.1099).
1
solid. The H NMR and mass spectral data were con-
sistent with those already reported.36
3.1.10. CycloABA-GE tetraacetate. CycloABA-GE tetra-
acetate was synthesized from CycloABA (5 mg,
19 mmol) in the same manner as was used to produce
ABA-GE tetraacetate; the process gave CycloABA-GE
tetraacetate (0.45 mg, 4% yield) as a white amorphous
3.1.6. (Æ)-50ꢀ,80-Cyclo-ABA. KN(TMS)2 (15% in tolu-
ene, 2.5 mL, 1.9 mmol) was added to a solution of
bis(2,2,2 - trifluoroethyl)(methoxycarbonylmethyl)pho-
sphonate (0.39 g, 1.2 mmol) in dry THF (10 mL), and
the mixture was stirred for 1 h at 0 ꢀC under Ar. A
solution of 4 (0.18 g, 0.84 mmol) in dry THF (3 mL) was
then added and the resulting mixture was stirred for 7 h
at room temperature. After being quenched with satu-
rated NH4Cl, the mixture was extracted with ether
(15 mL Â 4). The organic layer was washed with H2O,
dried over Na2SO4 and concentrated. Column chroma-
tography with hexane–EtOAc (10:3–5:2) gave a 2Z/2E
mixture of 5 (0.11 g) as a pale yellow oil. A solution of
1 M NaOH (4 mL, 4 mmol) was added to 5 in MeOH
(2 mL), and stirred for 18 h at room temperature in the
dark. H2O (50 mL) was added to the resulting mixture.
The solution was extracted with hexane and the aqu-
eous layer was extracted with EtOAc (10 mL Â 8) after
being acidified with 1 M HCl to pH 2. The organic layer
was washed with brine and H2O, dried over Na2SO4
and concentrated. The residual oil was purified by col-
umn chromatography with CH2Cl2–acetone–AcOH
(190:10:1–180:20:1) to give (Æ)-50a,80-cycloABA (0.43 g,
1
solid. H NMR: d 1.12 (1H, dd, J=8.6 and 4.3 Hz, H-
80), 1.20 (3H, s, H3-90), 1.27 (1H, dd, J=4.3 and 4.3 Hz,
H-80), 1.86 (3H, d, J=1.3 Hz, H3-70), 1.87 (1H, m, H-50),
2.01 (3H, s, OAc), 2.02 (3H, s, OAc), 2.03 (3H, s, OAc),
2.04 (3H, s, OAc), 2.09 (3H, s, H3-6), 3.83 (1H, m, H-
500), 4.11 (1H, dd, J=12.6 and 1.9 Hz, H-600), 4.28 (1H,
dd, J=12.6 and 4.6 Hz, H-600), 5.12 (1H, t, J=9.1 Hz,
H-400), 5.17 (1H, t, J=9.1 Hz, H-200), 5.22 (1H, t,
J=9.1 Hz, H-300), 5.63 (1H, s, H-30), 5.74 (1H, s, H-2),
5.78 (1H, d, J=8.1 Hz, H-100), 5.92 (1H, d, J=15.7 and
Hz, H-5), 7.87 (1H, d, J=15.7 Hz, H-4); FABHRMS
(NBA): [M+H]+ at m/z 593.2241 (calcd for C29H37O13,
m/z 593.2234).
3.1.11. Calculations. The minimum-energy conformers
of ABA and CycloABA were minimized using the Becke
three parameter functional (B3LYP) method with the 6-
31G(d) basis set in Gaussian 03.37 The C–H bond ener-
gies of cyclopropane and propane were estimated by
calculating the energies of these compounds, their
dehydrogenated radicals, and a hydrogen atom using
the restricted (for ethane and cyclopropane), or unrest-
ricted (for their radicals), Quadratic CI [QCISD(T)]
with the 6-311++G(2d,p) basis set. Zero-point and
thermal corrections (298.15 K) were calculated using
unrestricted B3LYP with a 6-311G(d,p) basis set.
1
20% yield) as a white amorphous solid. The H NMR
and mass spectral data were consistent with those
reported previously.19
3.1.7. Optical resolution of (Æ)-50ꢀ,80-cyclo-ABA. A
Chiralpak AD-H HPLC column (250 mm  4.6 mm
i.d., Daicel; solvent, 8% i-PrOH in hexane containing
0.1% TFA; flow rate, 1.5 mL minÀ1; detection, 254 nm)
was injected with (Æ)-50a,80-cyclo-ABA. The materials
with retention times of 14.1 and 17.4 min were collected,
3.2. Biology
3.2.1. Plant material. Seeds of radish [R. sativus L. var.
raphanistroides (Makino) Sinsk.] were sown on a stain-
less mesh in a glass dish (60 mm  110 mm i.d.), soaked
in water at 25 ꢀC in the dark for a day, and grown at
providing
17.3 mg
of
(+)-50a,80-cyclo-ABA