Zhao et al.
) 0.5 Hz), 4.45 (d, 1H, J ) 2.6 Hz), 2.23 (td, 2H, J ) 13.4, 4.8
Hz), 2.18 (tt, 1H, J ) 10.2, 3.9 Hz), 2.11 (dm, 1H, J ) 16.3
Hz), 1.94 (td, 1H, J ) 12.9, 3.8 Hz), 1.89 (ddd, 1H, J ) 17.0,
5.0, 2.0 Hz), 1.82 (dt, 1H, J ) 14.1, 2.8 Hz), 1.74 (s, 3H), 1.46
(s, 3H), 1.36 (app t, 1H, J ) 13.8 Hz), 0.96 (d, 3H, J ) 6.9 Hz);
13C NMR (126 MHz, CDCl3) δ 194.0, 153.3, 149.1, 139.6, 129.6,
129.5, 126.4, 122.0, 108.9, 80.5, 74.5, 44.5, 43.5, 40.0, 39.2, 32.4,
31.9, 30.2, 21.0, 10.3; FTIR (neat film) ν 3413.1, 2975.1, 2922.7,
1643.7, 1590.4, 1490.3, 1450.2, 1378.6, 1356.6, 1326.1, 1285.0,
1198.5, 1161.0, 1146.2, 1119.0, 1071.4, 1033.7, 1011.3, 963.4,
Con clu sion
Epieremophilane sesquiterpenes are readily accessible
by functional modifications of capsidiol. Both deoxycap-
sidiol isomers 9 and 10 are now available for kinetic
studies to elucidate the sequence of oxidation steps
effected by epiaristolochene dihydroxylase. The novel
epimers and regioisomers of epiaristolochene character-
ized in this work have an important role in studies on
the specificity and mechanism of epiaristolochene syn-
thase, dihydroxylase, and their mutant forms.22
918.1, 891.5, 869.9, 824.5, 808.0, 771.8, 740.6, 688.6 cm-1
;
HRMS (FAB) m/z calcd for C22H28O3S (M + H)+ 373.1834.
Found 373.1834.
3-Deoxyca p sid iol (4-Ep ier em or p h ila -9,11-d ien -1â-ol)
(10). The general procedure of Fu was followed.24 To 13a (75
mg, 0.20 mmol, 1 equiv) in 4 mL of benzene at room temper-
ature was added a solution of (Bu3Sn)2O (10 µL, 0.02 mmol,
0.1 equiv), AIBN (5 mg, 0.03 mmol, 0.15 equiv), and PMHS
(120 µL, 2 mmol, 10 equiv) in benzene (4 mL). After 5 min at
room temperature, the reaction mixture was heated at reflux
for 5 h, cooled to room temperature, and concentrated. THF
(5 mL) and aqueous NaOH (2 M, 3 mL) were added. The
mixture was stirred for another 12 h at room temperature,
and the aqueous layer was extracted with Et2O (3 × 20 mL).
The combined organic extracts were washed with brine (2 ×
10 mL), dried (MgSO4), and concentrated. Purification by
chromatography (6:1 hexane/ethyl acetate) afforded 3-deoxy-
capsidiol (10, 36 mg, 81%) as a pale yellow oil: TLC Rf ) 0.20
(6:1 hexane/ethyl acetate); HPLC tR (14 min, 16 mL/min, 6:1
Exp er im en ta l Section
Elicita tion a n d Isola tion of Ca p sid iol (1) fr om Gr een
P ep p er s.20,22a,39 Two opposing needle holes were made in the
upper portion of 150 green bell pepper fruits with a 16-gauge
needle. The peppers were filled with a 1.1 mg/L solution of
cellulase (Tricoderma viride) in deionized water by a gravity
feed through a 0.25-in. tube ending with a short Pasteur pipet.
After 72 h at room temperature, the sides of the peppers were
cut open and the aqueous solution was filtered through
cheesecloth into 20-gallon plastic barrels. Batches (1 L) of the
combined aqueous solution were extracted with CH2Cl2 (2 ×
0.25 L). Concentration of the combined CH2Cl2 layers and
purification by flash chromatography (1:6 hexane/ethyl ac-
etate) provided 0.452 g (3.0 mg/pepper) of white crystalline
capsidiol. The purity was shown to be essentially 100% by GC
hexane/ethyl acetate); [R]25 ) -12.7 (c ) 0.71, CHCl3); 1H
1
and H NMR analyses: mp (uncorrected) 149.5-151 °C (lit.6a
D
NMR (400 MHz, CDCl3) δ 5.87 (dd, 1H, J ) 6.8, 2.1 Hz), 4.70
(m, 1H), 4.67 (m, 1H), 4.25 (t, 1H, J ) 2.7 Hz), 2.34 (tt, 1H, J
) 13.7, 4.7 Hz), 2.14 (tt, 1H, J ) 12.1, 3.3 Hz), 2.04 (dddd,
1H, J ) 16.2, 6.8, 4.0, 2.8 Hz), 1.86 (ddd, 1H, J ) 16.2, 11.4,
2.1 Hz), 1.78 (tt, 1H, J ) 14.3, 4.1 Hz), 1.75 (m, 3H), 1.70 (m,
2H), 1.59 (m, 1H), 1.36 (s, 3H), 1.30 (dd, 1H, J ) 13.3, 11.1
Hz), 1.29 (s, 1H), 1.19 (ddt, 1H, J ) 14.0, 4.3, 2.5 Hz), 0.95 (d,
3H, J ) 7.0 Hz); 13C NMR (126 MHz, CDCl3) δ 149.8, 142.0,
127.4, 108.5, 74.8, 44.5, 41.2, 40.3, 38.0, 32.6, 30.3, 27.9, 24.8,
21.0, 16.7; FTIR (neat film) ν 3369.4, 2919.1, 2873.1, 1643.2,
mp 152-153 °C); TLC Rf ) 0.21 (1:6 hexane:ethyl acetate);
[R]25 ) +21.3 (c ) 1.75, CHCl3) [lit.6a [R]25 ) +21 (c ) 2.1,
D
D
1
CHCl3)]; GC (100%); H NMR (500 MHz, CDCl3) δ 5.93 (dd,
1H, J ) 7.0, 2.0 Hz), 4.72 (t, 1H, J ) 1.5 Hz), 4.69 (d, 1H, J )
1.0 Hz), 4.59 (dt, 1H, J ) 12.5, 4.5 Hz), 4.36 (dd, 1H, J ) 3.7,
2.3 Hz), 2.18 (tt, 1H, J ) 12.3, 3.5 Hz), 2.08 (dddd, 1H, J )
16.5, 6.7, 4.0, 3.0 Hz), 1.94 (d of septets, 1H, J ) 13.5, 1.0 Hz),
1.87 (ddd, 1H, J ) 16.5, 11.5, 2.0 Hz), 1.80 (dt, 1H, J ) 14.0,
3.0 Hz), 1.75 (m, 1H), 1.74 (s, 3H), 1.66 (ddd, 1H, J ) 13.5,
12.5, 4.0 Hz), 1.37 (m, 2H), 1.37 (s, 3H), 1.33 (dd, 1H, J ) 13.9,
13.1 Hz), 0.88 (d, 3H, J ) 7.0 Hz); 13C NMR (100 MHz, CDCl3)
δ 149.4, 140.3, 129.0, 108.7, 75.0, 65.4, 47.6, 44.9, 40.1, 39.1,
36.1, 32.1, 30.3, 21.0, 8.9. The NMR data agree with the
literature values.10 However, more complete analyses and
assignments are given above.
1454.7, 1374.7, 1063.5, 1012.1, 950.0, 914.1, 886.4, 819.3 cm-1
;
HRMS (EI) m/z calcd for C15H24O (M+) 220.1827. Found
220.1826.
Ep ia r istoloch en -1-on e (22). The general procedure of
Heathcock was followed.40 Oxalyl chloride (47 mg, 32 mL, 0.37
mmol) and DMSO (55 mg, 50 mL, 0.71 mmol) were dissolved
in CH2Cl2 (3 mL), and the solution was cooled to -78 °C.
3-Deoxycapsidiol (10) (45 mg, 0.20 mmol) in CH2Cl2 (3 mL)
was then added slowly. The reaction mixture was stirred at
-78 °C for 20 min; triethylamine (145 mg, 200 mL, 1.44 mmol)
was added, and the solution was maintained at room temper-
ature for another 20 min. The solution was washed with brine
(10 mL); the aqueous layer was extracted with Et2O (3 × 20
mL), and the combined organic layers were dried (MgSO4) and
concentrated. Purification of the crude product by flash chro-
matography (7:1 hexane/ethyl acetate) provided the enone 22
(38 mg, 88%) as a clear oil. The purity of the product was
shown to be 99% by GC (program 1) and 1H NMR analyses.
Data for 22: TLC Rf ) 0.42 (5:1 hexane/ethyl acetate); GC
Ca p sid iol 3-P h en ylth ion oca r bon a te (13a ). The general
procedure of Fu24 was followed. A solution of capsidiol (1) (85
mg, 0.36 mmol, 1.0 equiv) in pyridine (1.4 g, 1.5 mL, 18 mmol)
and CH2Cl2 (1.5 mL) was stirred and cooled at 0 °C as phenyl
chlorothionoformate (65 µL, 0.47 mmol, 1.3 equiv) was added
over 2-3 min. After 10 min, the solution was warmed to room
temperature and stirred for 8 h. MeOH (25 µL, 0.61 mmol)
was added, and the reaction mixture was stirred for another
1 h. The solution was diluted with Et2O (15 mL), and aqueous
HCl (1 M, 10 mL). The aqueous layer was extracted with Et2O
(3 × 25 mL). The combined Et2O extracts were washed with
saturated Cu(NO3)2 (2 × 15 mL) and H2O (10 mL), dried
(MgSO4), and concentrated. Purification of the crude product
(120 mg) by chromatography on silica gel (4:1 hexane:ethyl
acetate) provided capsidiol 3-phenylthionocarbonate (13a ) (105
mg, 80%) as a brown oil: TLC Rf ) 0.28 (4:1 hexane:ethyl
(99%) (program 1); [R]25 ) -10.6 (c ) 1.35, CHCl3); 1H NMR
D
(500 MHz, CDCl3) δ 6.60 (dd, 1H, J ) 7.2, 2.2 Hz), 4.74
(quintet, 1H, J ) 1.5 Hz), 4.70 (septet, 1H, J ) 1.0 Hz), 2.40
(m, 2H), 2.27 (m, 2H), 2.19 (tt, 1H, J ) 12.1, 3.8 Hz), 1.93 (ddd,
1H, J ) 10.0, 6.4, 2.4 Hz), 1.90 (ddd, 1H, J ) 7.4, 3.7, 2.0 Hz),
1.75 (s, 3H), 1.73 (m, 1H), 1.61 (ddt, 1H, J ) 13.8, 7.0, 2.3
Hz), 1.35 (dd, 1H, J ) 13.9, 13.0 Hz), 1.14 (s, 3H), 1.13 (d, 3H,
J ) 7.1 Hz); 13C NMR (126 MHz, CDCl3) δ 204.2, 148.7, 143.5,
133.3, 109.3, 42.5, 40.8, 40.6, 39.8, 35.5, 31.4, 30.2, 27.7, 21.0,
16.6; FTIR (neat film) ν 2962.5, 2932.4, 2880.5, 1692.3, 1632.9,
1
acetate); H NMR (500 MHz, CDCl3) δ 7.41 (m, 2H), 7.28 (m,
1H), 7.10 (m, 2H), 6.10 (dt, 1H, J ) 12.3, 4.5 Hz), 5.96 (dd,
1H, J ) 6.9, 1.7 Hz), 4.74 (d, 1H, J ) 1.5 Hz), 4.70 (d, 1H, J
(36) Rasoamiaranjanahary, L.; Guilet, D.; Marston, A.; Randimbi-
vololona, F.; Hostettmann, K. Phytochemistry 2003, 64, 543-548.
(37) Ma, W. G.; Fuzzati, N.; Li, Q. S.; Yang, C. R.; Stoeckli-Evans,
H.; Hostettmann, K. Phytochemistry 1995, 39, 1049-1061.
(38) Atindehou, K. K.; Queiroz, E. F.; Terreaux, C.; Traore, D.;
Hostettmann, K. Planta Med. 2002, 68, 181-182.
(39) Mr. Tony Chriscoe and Ms. Wendy Marriner assisted in
developing this scale-up procedure.
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3251.
7434 J . Org. Chem., Vol. 69, No. 22, 2004