Synthesis and anti-fungal activity of seven oleanolic acid glycosides

Article abstract of DOI:10.3390/molecules16021113

In order to develop potential anti-fungal agents, seven glycoconjugates composed of α-L-rhamnose, 6-deoxy-α-L-talose, β-D-galactose, a-D-mannose, β-D-xylose- (1→4)-6-deoxy-α-L-talose, β-D-galactose-(1→4)-α-L-rhamnose, β-D-galactose-(1→3)- β- D-xylose-(1→4

Full text of DOI:10.3390/molecules16021113

Molecules 2011, 16, 1113-1128; doi:10.3390/molecules16021113
OPEN ACCESS
molecules
ISSN 1420-3049
www.mdpi.com/journal/molecules
Article
Synthesis and Anti-Fungal Activity of Seven Oleanolic Acid
Glycosides
Hanqing Zhao, Guanghui Zong, Jianjun Zhang *, Daoquan Wang and Xiaomei Liang *
Key Lab of Pesticide Chemistry and Application Technology, Department of Applied Chemistry,
China Agricultural University, Beijing 100193, China
* Authors to whom correspondence should be addressed; E-Mails: zhangjianjun@cau.edu.cn (J.Z.);
nmrlab@cau.edu.cn (X.L.); Tel.: +86-10-6273-1115.
Received: 7 December 2010; in revised form: 23 December 2010 / Accepted: 13 January 2011 /
Published: 26 January 2011
Abstract: In order to develop potential anti-fungal agents, seven glycoconjugates
composed of α-L-rhamnose, 6-deoxy-α-L-talose, β-D-galactose, α-D-mannose, β-D-xylose-
(1→4)-6-deoxy-α-L-talose, β-D-galactose-(1→4)-α-L-rhamnose, β-D-galactose-(1→3)-β-
D-xylose-(1→4)-6-deoxy-α-L-talose as the glycone and oleanolic acid as the aglycone were
synthesized in an efficient and practical way using glycosyl trichloroacetimidates as
1
13
donors. The structures of the new compounds were confirmed by MS, H-NMR and C-
NMR. Preliminary studies based on means of mycelium growth rate, indicated that all the
compounds possess certain fungicidal activity against Sclerotinia sclerotiorum (Lib.) de
Bary, Rhizoctonia solani Kuhn, Botrytis cinerea Pers and Phytophthora parasitica Dast.
Keywords: synthesis; oleanolic acid; glycoconjugate; anti-fungal activity
1. Introduction
During the course of growth and development, plants synthesize triterpenoid saponins which act as
preformed chemical barriers against fungal attack [1]. Aside from their important role in plant growth,
these glycosylated plant secondary metabolites show various kinds of biological activity and have been
used widely as anti-inflammatory, anti-tumor, anti-HIV, and antifungal agents [2]. Consequently,
triterpenoid saponin structures have become the synthetic targets of many research groups [3,4]. One
common feature shared by all saponins is the presence of a sugar chain at the C-3 of the aglycone

Molecules 2011, 16
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moiety [5,6]. These chains vary from saponin to saponin but usually consist of glucose, arabinose,
glucuronic acid, xylose or rhamnose [7].
Recently Yadava et. al. reported a new triterpenoid saponin isolated from the seeds of L. scariola,
which had the structure of 3-O-[β-D-galactopyranosyl-(1→3)-O-β-D-xylopyranosyl-(1→4)-O-α-L-
rhamnopyranosyl]-oleanolic acid (Figure 1, I) [8]. Interestingly, this triterpenoid saponin exhibited
broad spectrum antibacterial and antifungal activities against Staphylococcus aureus, Escherichia coli,
Penicillium digitatum and Aspergillus niger [8]. In a project for the discovery of novel
environmentally friendly antifungal agents from natural resources, we engaged in the study of the
synthesis and anti-fungal activity of glycoconjugate derivatives 1-7. We report herein the preliminary
results of the study.
Figure 1. Structure of the triterpenoid saponin (I) and target compounds 1–7.
COOH
COOH
R
O
OH
O
HO
HO
O
H3C
O
1:
2:
3:
7:
HO
O
O
4:
5:
6:
R= Rhap
R= 6-deoxy-Talp
R= Galp
R= Manp
R= Xylp(1
R= Galp(1
O
4)-6-deoxy-Talp
4)Rhap
HO
OH
OH
OH
4)-6-deoxy-Talp
R= Galp(1
3)Xylp(1
I
2. Results and Discussion
2.1. Chemistry
As shown in Figure 2, we envisioned that the target compounds 1-7 could be synthesized using nine
suitably protected building blocks 9-16.
Figure 2. The building blocks 9-16 used for the synthesis of target compounds 1-7.
Target compounds 1-7
OCNHCCl3
AcO
AcO
O
AcO
AcO
H3C
AllylO
O
COOBn
BzO
OBz
OCNHCCl3
13
10
OCNHCCl3
HO
9
O
H3C
O
BzO
BzO
BzO
OBz
OBz
AllylO
OBz
OBz
OCNHCCl3
COOBn
11
14
OCNHCCl3
H3C
OBz
O
O
OBz
BzO
O
O
BzO
O
O
BzO
BzO
OBz
BzO
OBz
HO
OBz
OCNHCCl3
16
12
15

Molecules 2011, 16
1115
In our work, the Schmidt method [9] was used in the glycosylation, and benzyl was chosen as the
protective group for the COOH group to avoid difficulties in the final deprotection.Since the synthons
9 [10], 12 [11], 13 [12] and 14 [13] were easily prepared according to the reported procedures, our
attention was focused on the synthesis of 4-O-allyl-2,3-di-O-benzoyl-α-L-rhamnopyranosyl
trichloroacetimidate (10), 4-O-allyl-2,3-di-O-benzoyl-6-deoxy-α-L-talopyranosyl trichloroacetimidate
(11), 2,3,4,6-tetra–O-benzoyl-β-D-galactopyranose-(1→3)-2,4-di-O-benzoyl-β-D-xylopyranosyl tri-
chloroacetimidate (15) and benzyl oleanolate 3-O-2,3-di-O-benzoyl-α-L-talopyranoside (16) (Scheme 1).
Scheme 1. Synthetic routes to the compounds 10, 11, 15 and 16.
OPMP
OPMP
OPMP
OPMP
H3C
AllylO
O
H3C
O
H3C
O
c
H3C
HO
O
a
c
a
11
AllylO
10
R1O
O
R1O
O
OH
O
C
OR2
OR2
O
C
Me2
Me2
21 R1 = R2 = isopropylidene
22 R1 = R2 = Bz
18 R1 = R2 = isopropylidene
19 R1 = R2 = Bz
b
b
20
17
R1O
O
O
11
9
R2O
Me2C
OBz
BzO
O
OH
O
O
O
d
O
12, d
O
COOBn
O
23 R =Allyl
16 R = H
RO
BzO
O
O
O
OBz
BzO
CMe2
e
24
CMe2
BzO
25 R1 = R2 = isopropylidene
26 R1 = R2 = H
f
O
OH
O
O
O
HO
OBz
O
BzO
OBz
OBz
O
BzO
g
O
O
OBz
h
i
O HO
OH
26
O
O
O
OBz
j
BzO
BzO
OBz
O
15
29
OBz
CMe2
CMe
2 BzO
O
28
27
Reagents and conditions: (a) AllBr, NaH, DMF, 0 °C, 2 h, 95% for 18, 92% for 21; (b) 70% HOAc,
70 °C, 2 h; then BzCl-Py. 88% for 19 (2 steps), 80% for 22 (2 steps); (c) 80% MeCN, CAN, 35 °C,
20 min; then CNCCl3, CH2Cl2, DBU, 4 h, 72% for 10 (2 steps), 70% for 11 (2 steps). (d) TMSOTf,
CH2Cl2, -10 °C to r.t., 2 h, 85% for 23, 88% for 25. (e) MeOH-CH2Cl2 = 1/1, PdCl2, r.t. 92% for 16.
(f) 60% HOAc, r.t. 83% for 26. (g) NaIO4-SiO2, CH2Cl2, 88% for 27. (h) NaBH4, EtOAc-H2O = 7:3,
0 °C to r.t., 15 min, 96% for 28. (i) 4% H2SO4, reflux 3-4 h, 85% for 29. (j) Py, BzCl, then 2 M
MeOH-NH3, 2 h, then CNCCl3, CH2Cl2, DBU, 4 h, 68% for 15 (3 steps).
Among these compounds, donor 10 was prepared from the known p-methoxyphenyl 2,3-O-
isopropylidene-α-L-rhamnopyranoside (17) [14]. Allylation of 17 with allyl bromide provided the
corresponding
p-methoxyphenyl
4-O-allyl-2,3-O-isopropylidene-α-L-rhamnopyranoside
18
quantitatively; then removal of the isopropylidene group with 70% HOAc followed by benzoylation
gave 19 in high yield (88%); finally, cleavage of the p-methoxyphenyl glycoside in 19 with ceric
ammonium nitrate (CAN) followed by trichloroacetimidation afforded the corresponding glycosyl
donor 10 in 72% yield. Meanwhile, the donor 11 was prepared in a similar way, i.e., allylation of 20
[15] provided the corresponding p-methoxyphenyl 4-O-allyl-2,3-O-isopropylidene-6-deoxy-α-L-talo-
pyranoside 21 quantitatively; and removal of the isopropylidenyl group followed by benzoylation gave
22 in high yield (80%); finally, cleavage of the p-methoxyphenyl glycoside in 22 with ceric
ammonium nitrate (CAN) followed by trichloroacetimidation afforded the corresponding glycosyl
donor 11 in 70% yield. Condensation of donor 11 with C-3-OH acceptor 9 [10] in the presence of

Molecules 2011, 16
1116
1
TMSOTf gave the α-linked 6-deoxy-taloside 23, whose H-NMR spectrum showed characteristic
signals of a doublet at δ 5.42 ppm (J1,2 = 3.6 Hz) for the H-1 of 6-deoxytalose, a multiplet at δ 5.88
ppm for CH2=CH-CH2O, and seven singlets at δ 1.12, 1.01, 0.92, 0.91, 0.89, 0.83, 0.60 ppm for the
CH3 groups of oleanolic acid. Deallylation of 23 with PdCl2 gave the desired acceptor 16, and the 1H-
NMR showed that the characteristic allyl signals had disappeared.
On the other hand, we have also developed a novel strategy for the synthesis of 2,3,4,6-tetra–O-
benzoyl-β-D-galactopyranose-(1→3)-2,4-di-O-benzoyl-β-D-xylopyranosyl trichloroacetimidate 15
from 2,3,4,6-tetra–O-benzoyl-β-D-galactopyranosyl trichloroacetimidate 12 and 1,2:5,6-di-O-
isopropylidene-α-D-glucofuranose 24 [16]. 2,3,4,6-Tetra-O-benzoyl-β-D-galactopyranose-(1→3)-1,2-
O-isopropylidene-β-D-xylose 28 was conveniently prepared from 25 in 70% overall yield, via selective
removal of the 5,6-O-isopropylidene group followed by NaIO4 oxidation and NaBH4 reduction in a
similar way as reported in [17]. Subsequently, hydrolysis of 28 was carried out in an aqueous solution
of sulfuric acid (4%) under heating at reflux, and the reaction was accompanied by ring expansion [18]
to provide 2,3,4,6-tetra–O-benzoyl-β-D-galactopyranose-(1→3)-β-D-xylose 29, which was
benzoylated with benzoyl chloride in pyridine. Regioselective removal of the 1-O-benzoyl group in 2
M MeOH-NH3 followed by trichloroacetimidation with trichloroacetonitrile [9] afforded building
block 15 in 68% yield (3 steps). Finally, condensation of the donor 10 with the acceptor 9 in the
presence of TMSOTf gave benzyl oleanolate 3-O-4-O-allyl-2,3-di-O-benzoyl-α-L-rhamnopyranoside
1
30 in 88% yield (Scheme 2). The structure was confirmed by its H-NMR spectrum, showing
characteristic signals at δ 4.97 ppm (J1,2 = 1.7 Hz) for the H-1 of rhamnose, δ 5.81 ppm for CH2=CH-
CH2O, and δ 1.12, 1.02, 0.92, 0.92, 0.89, 0.88, 0.61 ppm for CH3 of oleanolic acid, the 13C-NMR
spectrum showed peaks at δ 99.6 ppm for anomeric C-1. Deallylation of 30 gave the desired acceptor
31 in 94% yields. The other five oleanolic acid glycosides 34, 36, 38, 40 and 42 were prepared from
condensation of the donors and the acceptors 12 and 9, 13 and 9, 14 and 16, 12 and 31, 15 and 16
respectively, giving 86%~90% yields.
Scheme 2. Synthesis of the target compounds 1-7.
COOR3
a
COOH
c
9
10
16
O
30 R
1
=Allyl, R
= H, R = Bz, R
= H, R = Bz, R
= H, R
2
= Bz, R = Bn
3
O
b
c
31 R
1
2
3
= Bn
= H
H3C
R1O
O
H3C
O
33 R
1
= Bz
32 R
1
2
3
d
R2O
R1O
d
2 R
1
= H
OR2
1 R
1
= H, R
2
3
= H
HO
OR1
a
a
9
12
13
9
R1O
COOR2
OR1
R1O
COOR2
OR1
O
O
R1O
R1O
O
34 R
35 R
3 R
1
= Bz, R
2
= Bn
= H
36 R
37 R
4 R
1
= Ac, R
= Ac, R
= H, R
2
= Bn
= H
R1O
c
c
O
1
= Bz, R
2
1
2
OR1
d
d
1
= H, R
2
= H
1
2
= H

Molecules 2011, 16
1117
Scheme 2. Cont.
O
38 R
39 R
5 R
1
= Bz, R
2
= Bn
= H
H3C
c
a
O
1
= Bz, R
2
R1O
R1O
14
12
16
31
O
COOR2
d
R1O
1
= H, R = H
2
O
R1O
O
OR1
OR1
OR1
40 R
41 R
6 R
1
= Bz, R
= Bz, R
= H, R
2
= Bn
= H
O
c
a
1
2
O
H3C
O
COOR2
d
R1O
1
2
= H
R1O
OR1
OR1
O
OR1
H3C
O
OR1
COOR2
a
16
15
O
O
R1O
42 R
1
= Bz, R
= Bz, R
= H, R = H
2
= Bn
R1O
c
O
O
R1O
43 R
1
2
= H
OR1
OR1
OR1
d
7 R
1
2
Reagents and conditions: (a) TMSOTf, CH2Cl2, -10 °C to r.t., 2 h, 88% for 30, 90% for 34, 86% for
36, 90% for 38, 89% for 40, 90% for 42; (b) PdCl2, MeOH, 94% for 31; (c) Pd-C, H2, 12 h; (d)
MeOH-MeONa, 25 h, 86% for 1, 81% for 2, 84% for 3, 87% for 4, 71% for 5, 68% for 6, 75%
for 7.
The 28-O-benzyl groups in 31, 16, 34, 36, 38, 40, 42 were removed with Pd-C under H2
atmosphere, and then the O-benzoyl groups were cleaved with MeOH-MeONa [19], furnishing the
target compounds 1-7 in satisfactory yields, the structure of the target compounds were established by
1H-NMR and 13C-NMR spectroscopy. For example, the 1H-NMR spectrum of 7 showed characteristic
signals such as δ 5.26, 5.25, 4.72 ppm for three H-1, and δ 1.28, 1.00, 0.99, 0.95, 0.90, 0.83, 0.78 for
13
the CH3 groups of oleanolic acid, the C-NMR spectrum showed peaks at δ 106.3, 105.9, 104.9 ppm
for three anomeric C-1s.
2.2. Bioassay of Fungicidal Activities
Fungicidal activities of the target compounds against Sclerotinia sclerotiorum (Lib.) de Bary,
Rhizoctonia solani Kuhn, Botrytis cinerea Pers and Phytophthora parasitica Dast were evaluated
using the mycelium growth rate test [20]. The diameter of the mycelia was measured and the inhibition
rate was calculated according to formula (1):
2
2
D1 − D0
I =
×100%
(1)
2
D1
where I is the inhibition rate,
is the average diameter of mycelia in the blank test, and
is the
D0
D1
average diameter of mycelia in the presence of compounds 1-7: The inhibition rates of compounds 1-7
against the four fungi at 50 µg/mL are given in Table 1. Compounds 1-7 exhibited more fungicidal
activity against R. solani than the other fungi, compounds 1 and 2 are more active against B. cinerea
and Phytophthora parasitica Dast than the other compounds.

Molecules 2011, 16
1118
Table 1. Inhibition Rate of Compounds 1-7 against four Fungi.
Inhibition rate (%)
Compd no.
S. sclerotiorum
R. solani
B. cinerea
Phytophthora
parasitica Dast
79.21
1
2
3
4
5
6
7
71.90
67.35
78.27
65.16
73.47
71.90
71.10
96.05
93.24
95.29
96.17
93.86
95.93
88.48
75.41
77.29
68.42
74.59
71.73
71.44
67.17
83.54
67.24
63.55
52.57
69.72
70.06
3. Experimental
3.1. General methods
Solvents were purified in the usual way. All commercially available reagents were used as received.
All reactions were monitored by TLC analysis and TLC was performed on silica gel HF with detection
by charring with 30% (v/v) H2SO4 in CH3OH or by UV detection. Column chromatography was
conducted by elution of a column (8 × 100, 16 × 240, 18 × 300, 35 × 400mm) of silica gel (200-300
mesh) with EtOAc-PE (b.p. 60-90 °C) as the eluent. Air and moisture sensitive reactions were
performed under dry N2 atmosphere. Optical rotations were recorded using a Perkin-Elmer 241
polarimeter. NMR spectra were recorded on a Varian XL-300 spectrometer with TMS as the internal
standard. Elemental analysis was performed on a Yanaco CHN Corder MF-3 automatic elemental
analyzer. Mass spectra were recorded with a VG PLATFORM mass spectrometer using the
electronspray ionization (ESI) mode. Solutions were concentrated at a temperature <60 °C under
diminished pressure.
3.2. Chemical synthesis
p-Methoxyphenyl 4-O-allyl-2,3-O-isopropylidene-α-L-rhamnopyranoside (18). Sodium hydride (2.3 g,
47.4 mmol) and allyl bromide (3.6 mL, 41.1 mmol) were successively added to a soln. of compound
17 [14] (9.8 g, 31.6 mmol) in N,N-dimethylformamide (50 mL) which was cooled in an ice-salt bath.
Then the reaction mixture was slowly allowed to reach room temperature and stirred for 20 min at the
end of which time TLC (4:1 petroleum ether-EtOAc) indicated that the reaction was complete. The
reaction mixture was diluted with EtOAc (100 mL), washed with ice-water, and dried (Na2SO4). The
soln was concentrated, and the residue was subjected to column chromatography (8:1 petroleum ether-
EtOAc) to give the desired product 18 (10.5 g, 95%) as a foamy solid. Rf = 0.68 (4:1 petroleum ether-
25
1
EtOAc); [α]D -61.4 (c 0.5, CHCl3); H-NMR (CDCl3): δ 7.00-6.81 (m, 4 H, Bz-H), 5.93 (m, 1 H,
CH2=CH-CH2O), 5.59 (s, 1 H, H-1), 5.32-5.16 (m, 2 H), 4.40-4.32 (m, 3 H), 4.14 (m, 1 H), 3.83-3.77
(m, 4 H, H-5, OCH3), 3.21 (m, 1 H), 1.56 (s, 3 H, CH3), 1.40 (s, 3 H, CH3), 1.23 (d, 3 H, J = 6.3 Hz, H-
6). Anal. Calcd. for C19H26O6: C, 65.13; H, 7.48; found: C, 65.29; H, 7.63.

Molecules 2011, 16
1119
p-Methoxyphenyl 4-O-allyl-2,3-di-O-benzoyl-α-L-rhamnopyranoside (19). Compound 18 (7.8 g,
22.3 mmol) was dissolved in 70% HOAc (200 mL) and stirred for 2 h at 75 °C, at the end of which
time TLC (2:1 petroleum ether-EtOAc) indicated the completion of the reaction. The mixture was
concentrated under reduced pressure and then coevaporated with toluene (2 × 40 mL). To a soln of the
residue (7.3 g, 23.5 mmol) in pyridine (60 mL) was added benzoyl chloride (8.2 mL, 70.5 mmol)
dropwise. After stirring for 8 h at rt, TLC (3:1 petroleum ether-EtOAc) indicated that the reaction was
complete. Methanol (1 mL) was added to quench the reaction and then water (100 mL) was added to
the reaction mixture. The aq. soln. was extracted with EtOAc (3 × 200 mL), the extract was washed
with 1 M HCl and saturated aq. sodium bicarbonate, dried (Na2SO4) and concentrated. The residue was
passed through a short silica-gel column with 6:1 petroleum ether-EtOAc as the eluent to give 19
(10.2 g, 88% for two steps) as a foamy solid. Rf = 0.42 (4:1 petroleum ether-EtOAc); [α]2D5 +21.1 (c
1
0.5, CHCl3); H-NMR (CDCl3): δ 8.07-7.34 (m, 10 H, Bz-H), 7.08-6.83 (m, 4 H, MeOC6H4), 5.87-
5.75 (m, 3 H), 5.52 (d, 1 H, J = 1.8 Hz, H-1), 5.17 (m, 1 H), 5.08 (m, 1 H), 4.20-4.08 (m, 3 H), 3.78-
3.71 (m, 4 H, H-5, OCH3), 1.41 (d, J = 6.2 Hz, 3 H, H-6); Anal. Calcd. for C30H30O8: C, 69.49; H,
5.83; found: C, 69.55; H, 5.58;
4-O-Allyl-2,3-di-O-benzoyl-α-L-rhamnopyranosyl trichloroacetimidate (10). To a soln. of 19 (10.0 g,
19.3 mmol) in 80% MeCN (200 mL) was added ceric ammonium nitrate (42.3 g, 77.2 mmol). The
mixture was stirred for 20 min at 35 °C, at the end of which time TLC (4:1 petroleum ether-EtOAc)
indicated that the reaction was complete. The solvents were evaporated in vacuo at 50 °C to give a
residue, which was dissolved in CH2Cl2, and washed with water. The organic phase was dried
(Na2SO4) and concentrated. Purification by silica gel chromatography with 5:1 petroleum ether-EtOAc
as the eluent afforded a foamy residue. The residue was dried under high vacuum for 2 h, then was
dissolved in dry CH2Cl2 (50 mL), trichloroacetonitrile (2.5 mL, 24.3 mmol) and 1,8-diaza-
bicyclo[5.4.0] undecene (DBU) (0.3 mL, 30 mmol) were added. The mixture was aged under the
nitrogen atmosphere until completion (TLC, 4:1 petroleum ether-EtOAc). Concentration of the
reaction mixture and purification of the residue by column chromatography (5:1 petroleum ether-
EtOAc) gave 10 (7.6 g, 72% for two steps) as a white foamy solid. Rf = 0.67 (4:1 petroleum ether-
25
1
EtOAc); [α]D +39.3 (c 0.5, CHCl3); H-NMR (CDCl3): δ 8.74 (s, 1 H, C=NH), 8.06-7.34 (m, 10 H,
Bz-H ), 6.39 (d, 1 H, J = 1.9 Hz, H-1), 5.85-5.71 (m, 3 H), 5.21-5.07 (m, 2 H), 4.22-4.15 (m, 3 H), 3.77
(dd, 1 H, J = 9.6, 9.6 Hz, H-4), 1.48 (d, J = 6.2 Hz, 3 H, H-6). Anal. Calcd. for C25H24Cl3NO7: C,
53.93; H, 4.34; N, 2.52; found: C, 53.79; H, 4.23; N, 2.29.
p-Methoxyphenyl 4-O-allyl-2,3-O-isopropylidene-6-deoxy-α-L-talopyranoside (21). Compound 20
(4.9 g, 15.8 mmol) was allylated under the same conditions as used for the preparation of 18 from 17,
giving 21 (5.1 g, 92%) as a foamy solid; Rf = 0.73 (4:1 petroleum ether-EtOAc); [α]2D5 -49.1 (c 0.5,
CHCl3); 1H-NMR (CDCl3): δ 7.01-6.80 (m, 4 H, Bz-H), 5.93 (m, 1 H, CH2=CH-CH2O), 5.56 (d, 1 H,
J = 1.5 Hz, H-1), 5.29-5.17 (m, 2 H), 4.49 (m, 1 H), 4.34-4.25 (m, 2 H), 4.09-4.00 (m, 2 H), 3.77 (s,
3 H, OCH3), 3.60 (m, 1 H), 1.59 (s, 3 H, CH3), 1.40 (s, 3 H, CH3), 1.31 (d, 3 H, J = 6.6 Hz, H-6). Anal.
Calcd. for C19H26O6: C, 65.13; H, 7.48; found: C, 65.25; H, 7.29.

Molecules 2011, 16
1120
p-Methoxyphenyl 4-O-allyl-2,3-di-O-benzoyl-6-deoxy-α-L-talopyranoside (22). Sequential de-O-
isopropylidenation and then benzoylation of compound 21 (7.8 g, 22.3 mmol) under the same
conditions as those used for the preparation of 19 from 18, gave 22 (9.3 g, 80%) as a foamy solid;
25
1
Rf = 0.67 (3:1 petroleum ether-EtOAc); [α]D -7.7 (c 0.5, CHCl3); H-NMR (CDCl3): δ 8.25-7.25 (m,
10 H, Bz-H), 7.07-6.82 (m, 4 H, MeOC6H4), 5.93 (m, 1 H, CH2=CH-CH2O), 5.77 (dd, 1 H, J = 3.49,
3.34 Hz, H-3), 5.68-5.67 (m, 2 H), 5.29-5.12 (m, 2 H), 4.33-4.27 (m, 2 H), 4.07 (m, 1 H), 3.83-3.76
(m, 4 H, CH2=CH-CH2O, OCH3), 1.37 (d, J = 6.5 Hz, 3 H, H-6); Anal. Calcd. for C30H30O8: C, 69.49;
H, 5.83; found: C, 69.63; H, 5.66.
4-O-allyl-2,3-di-O-benzoyl-6-deoxy-α-L-talopyranosyl trichloroacetimidate (11). Compound 22 (5.0 g,
9.7 mmol) was trichloroacetimidated under the same conditions as used for the preparation of 10 from
19, giving 11 (3.7 g, 70% for two steps) as a foamy solid. Rf = 0.70 (4:1 petroleum ether-EtOAc); [α]2D5
+6.14 (c 0.5, CHCl3); 1H-NMR (CDCl3): δ 8.74 (s, 1 H, C=NH), 8.24-7.32 (m, 10 H, Bz-H), 6.48 (d,
J = 1.4 Hz, 1 H, H-1), 5.90 (m, 1 H), 5.67-5.62 (m, 2 H), 5.18-5.09 (m, 2 H), 4.31-4.07 (m, 2 H), 3.87
(m, 1 H), 3.70 (m, 1 H), 1.44 (d, J = 6.5 Hz, 3 H, H-6). Anal. Calcd. for C25H24Cl3NO7: C, 53.93; H,
4.34; N, 2.52; found: C, 53.87; H, 4.15; N, 2.78.
Benzyl oleanolate 3-O-4-O-allyl-2,3-di-O-benzoyl-6-deoxy-α-L-talopyranoside (23). Compound 11
(4.3 g, 7.8 mmol), 9 [10] (3.6 g, 6.4 mmol) and 4 Å molecular sieves (1.0 g) were added to anhydrous
redistilled CH2Cl2 (60 mL). TMSOTf (130 μL, 0.7 mmol) was added dropwise at -10 °C under
nitrogen protection. The reaction mixture was allowed to raise to rt and stirred for 2 h, and then
quenched with Et3N (2 drops). Filtration of the reaction mixture, concentration of the filtrate, followed
by purification of the residue by column chromatography (5:1 petroleum ether-EtOAc) provided 23
25
1
(5.2 g, 85%). Rf = 0.47 (8:1 petroleum ether-EtOAc). [α]D +39.3 (c 0.5, CHCl3), H-NMR (CDCl3): δ
8.23-7.30 (m, 15 H, Ar-H), 5.88 (m, 1 H, CH2=CH-CH2O), 5.53 (dd, 1 H, J = 3.4, 3.5 Hz, H-3'), 5.42
(m, 1 H), 5.29 (br s, 1 H, H-12), 5.23-5.02 (m, 5 H), 4.32-4.23 (m, 2 H), 4.03 (m, 1 H), 3.76 (s, 1 H,
CH2=CH-CH2O), 3.17 (dd, 1 H, J = 5.1, 10.7 Hz, H-3), 2.90 (dd, 1 H, J = 3.8, 13.7 Hz, H-18), 1.35 (d,
3 H, J = 6.5 Hz, H-6'), 1.12, 1.01, 0.92, 0.91, 0.89, 0.83, 0.60 (s, 7 × 3 H, CH3); 13C-NMR (CDCl3): δ
177.4, 166.3, 165.6 (3 C=O), 143.7, 136.4, 135.0, 133.1, 133.0, 130.3, 130.1, 129.7, 129.7, 128.4,
128.4, 128.4, 128.4, 128.4, 128.2, 128.2, 128.0, 128.0, 128.0, 127.9, 122.5, 116.7, 100.6 (C-1'), 89.3,
76.4, 74.3, 70.1, 69.0, 66.5, 65.9, 55.4, 47.6, 46.7, 45.9, 41.7, 41.4, 39.3, 39.0, 38.4, 36.7, 33.9, 33.1,
32.7, 32.4, 30.7, 28.3, 27.6, 25.8, 25.2, 23.6, 23.4, 23.1, 18.3, 16.9, 16.5, 16.5, 15.3; Anal. Calcd. for
C60H76O9: C, 76.56; H, 8.14; found: C, 76.65; H, 8.31.
Benzyl oleanolate 3-O-2,3-di-O-benzoyl-6-deoxy-α-L-talopyranoside (16). To a soln of compound 23
(5.0 g, 5.2 mmol) in MeOH-CH2Cl2 = 1/1 (50 mL) was added PdCl2 (304 mg, 1.0 mmol). The mixture
was stirred for 12 h, at the end of which time TLC (8:1 petroleum ether-EtOAc) indicated that the
reaction was complete. The reaction mixture was diluted with dichloromethane (100 mL), washed with
water and satd aq Na2CO3. The organic layer was concentrated, and the residue was passed through a
short silica gel column with 8:1 petroleum ether-EtOAc as the eluent to give 16 (4.4 g, 92%). Rf = 0.32
(8:1 petroleum ether-EtOAc). [α]2D5 +45.0 (c 0.5, CHCl3), 1H-NMR (CDCl3): δ 8.07-7.26 (m, 15 H, Ar-
H), 5.49-5.47 (m, 2 H), 5.29 (br s, 1 H, H-12), 5.07 (m, 3 H), 4.32-3.96 (m, 2 H, H-4', H-5'), 3.20 (dd,

Molecules 2011, 16
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1 H, J = 5.8, 9.8 Hz, H-3), 2.90 (dd, 1 H, J = 4.4, 13.9 Hz, H-18), 2.55 (d, 1 H, J = 11.1 Hz, OH), 1.34
(d, 3 H, J = 6.5 Hz, H-6'), 1.12, 1.02, 0.92, 0.92, 0.89, 0.85, 0.61 (s, 7 × 3 H, CH3); 13C-NMR
(CDCl3): δ 177.4, 165.5, 165.5 (3 C=O), 143.7, 136.5, 133.6, 133.2, 129.8, 129.8, 129.7, 129.7, 129.5,
128.7, 128.7, 128.4, 128.4, 128.3, 128.0, 128.0, 127.9, 127.9, 126.8, 122.5, 100.4 (C-1'), 89.8, 70.6,
70.2, 68.9, 66.7, 65.9, 55.4, 47.6, 46.8, 45.9, 41.7, 41.4, 39.3, 39.0, 38.4, 36.7, 33.8, 33.1, 32.7, 32.4,
30.7, 28.3, 27.6, 25.9, 25.3, 23.6, 23.4, 23.1, 18.3, 16.9, 16.5, 16.2, 15.3; Anal. Calcd. for C57H72O9: C,
75.97; H, 8.05; found: C, 75.83; H, 8.19.
2,3,4,6-Tetra-O-benzoyl-β-D-galactopyranose-(1→3)-1,2:5,6-di-O-isopropylidene-α-D-glucofuranose
(25). Compound 12 [11] (3.87 g, 5.2 mmol) and 24 [16] (1.24 g, 4.8 mmol) were coupled under the
same conditions as that used for the preparation of 23 from 11 and 9, giving 25 (3.5 g, 88%) as a
25
1
foamy solid. Rf = 0.16 (4:1 petroleum ether-EtOAc); [α]D -61.4 (c 0.5, CHCl3); H-NMR (CDCl3): δ
8.09-7.25 (m, 20 H, Bz-H), 5.99 (dd, 1 H, J = 0.8, 3.3 Hz), 5.76 (dd, 1 H, J = 7.9, 10.5 Hz, H-2'), 5.62
(dd, 1 H, J = 3.4, 10.4 Hz, H-3'), 5.50 (d, 1 H, J = 3.6 Hz), 4.95 (d, 1 H, J = 7.9 Hz, H-1'), 4.67 (dd, 1
H, J = 6.3, 11.1 Hz), 4.50-4.25 (m, 6 H), 4.16-4.03 (m, 2 H), 1.43, 1.42, 1.34, 1.12 (s, 4 × 3 H, CH3);
13C-NMR (CDCl3): δ 166.0, 165.5, 165.5, 164.9 (4 C=O), 133.6, 133.5, 133.3, 133.3, 129.9, 129.9,
129.9, 129.9, 129.9, 129.8, 129.6, 129.6, 129.4, 129.1, 129.0, 128.7, 128.7, 128.6, 128.6, 128.5, 128.5,
128.3, 128.3, 111.9, 108.6, 104.9, 100.6 (2 × C-1), 82.9, 81.8, 80.5, 77.2, 73.1, 71.8, 71.5, 69.9, 68.0,
66.3, 61.9, 26.7, 26.6, 25.9, 25.3; Anal. Calcd. for C46H46O15: C, 65.86; H, 5.53; found: C, 65.72;
H, 5.75.
2,3,4,6-Tetra-O-benzoyl-β-D-galactopyranose-(1→3)-1,2-O-isopropylidene-α-D-glucofuranose (26).
The compound 25 (3.0 g) was dissolved in 60% HOAc (100 mL) and stirred for 6 h at 25 °C, at the end
of which time TLC (2:1 petroleum ether-EtOAc) indicated the completion of the reaction. The mixture
was concentrated under reduced pressure and then co evaporated with toluene (2 × 40 mL). The
residue was passed through a short silica-gel column with 3:1 petroleum ether-EtOAc as the eluent to
give 26 (2.4 g, 83%) as a foamy solid. Rf = 0.68 (1:1 petroleum ether-EtOAc); [α]2D5 +98.2 (c 1.0,
1
CHCl3); H-NMR (CDCl3): δ 8.08-7.23 (m, 20 H, Bz-H), 6.01 (d, 1 H, J = 2.5 Hz), 5.79 (dd, 1 H,
J = 8.0, 10.5 Hz, H-2'), 5.61 (dd, 1 H, J = 3.4, 10.5 Hz, H-3'), 5.53 (d, 1 H, J = 3.7 Hz), 4.98 (d, 1 H,
J = 7.9 Hz, H-1'), 4.57 (d, 2 H, J = 6.1 Hz), 4.50-4.29 (m, 3 H), 4.23 (d, 1 H, J = 3.7 Hz), 4.19-4.07 (m,
13
3 H), 3.92-3.85 (m, 1 H), 3.69 (dd, 1 H, J = 5.7, 11.5 Hz, H-18), 1.42, 1.06 (s, 2 × 3 H, CH3); C-
NMR (CDCl3): δ 166.1, 165.5, 165.5, 164.8 (4 C=O), 133.8, 133.6, 133.4, 133.4, 133.3, 130.0, 129.9,
129.8, 129.8, 129.8, 129.6, 129.1, 129.0, 129.0, 128.8, 128.8, 128.7, 128.7, 128.6, 128.6, 128.5, 128.3,
128.3, 112.2, 105.2, 101.9 (2 × C-1), 83.6, 83.2, 80.0, 77.2, 72.4, 71.3, 69.5, 68.7, 68.0, 64.4, 62.2,
26.7, 26.2; Anal. Calcd. for C43H42O15: C, 64.66; H, 5.30; found: C, 64.49; H, 5.38.
2,3,4,6-Tetra-O-benzoyl-β-D-galactopyranose-(1→3)-5-aldehyde-1,2-O-isopropylidene-α-D-gluco-
furanose (27). To a vigorously stirred suspension of silicagel-supported NaIO4 reagent which was
prepared as the reported method [17] (2.0 g) in CH2Cl2 (5 mL) was added a soln of the compound 26
(0.8 g, 1 mmol) in CH2Cl2 (5 mL). The mixture was stirred at rt for 25 min, and TLC (2:1 petroleum
ether-EtOAc) indicated that the reaction was complete. The mixture was filtered, and the silica gel was
thoroughly washed with CHCl3. Purification by silica gel chromatography with 2:1 petroleum ether-

Molecules 2011, 16
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EtOAc as the eluent afforded 27 (0.7 g, 88%) as a foamy solid. Rf = 0.41 (2:1 petroleum ether-EtOAc);
[α]2D5 +70.2 (c 0.5, CHCl3); 1H-NMR (CDCl3): δ 9.68 (d, 1 H, J = 1.5 Hz, CHO), 8.08-7.25 (m, 20 H,
Bz-H), 5.97 (dd, 1 H, J = 0.9, 3.4 Hz), 5.74-5.59 (m, 3 H), 4.89 (d, 1 H, J = 7.8 Hz, H-1'), 4.70-4.54
(m, 3 H), 4.48-4.30 (m, 3 H), 1.44, 1.18 (s, 2 × 3 H, CH3); 13C-NMR (CDCl3): δ 197.9, 166.0, 165.7,
165.5, 164.8 (5 C=O), 133.7, 133.6, 133.3, 133.3, 130.3, 130.0, 130.0, 129.9, 129.8, 129.8, 129.8,
129.6, 129.6, 129.4, 129.2, 129.1, 129.0, 128.9, 128.8, 128.7, 128.7, 128.6, 128.5, 128.3, 112.8, 105.7,
100.6 (2 × C-1), 83.9, 83.0, 82.9, 77.2, 71.8, 71.5, 69.6, 67.9, 61.9, 26.6, 26.1; Anal. Calcd. for
C43H40O14: C, 66.15; H, 5.16; found: C, 66.34; H, 5.25.
2,3,4,6-Tetra-O-benzoyl-β-D-galactopyranose-(1→3)-1,2-O-isopropylidene-β-D-xylose (28). To a soln
of 27 (1.4 g, 1.8 mmol) in 7:3 EtOAc-H2O (50 mL) at 0 oC was added NaBH4 (109 mg, 2.7 mmol).
The mixture was stirred at 0 °C for 15 min, and TLC (3:1 petroleum ether-EtOAc) indicated that the
reaction was complete. The aq. soln. was extracted with EtOAc (3 × 100 mL), the extract was washed
with 1 M HCl and saturated aq sodium bicarbonate, dried (Na2SO4) and concentrated. Purification by
silica gel chromatography with 5:1 petroleum ether-EtOAc as the eluent afforded 28 (1.3 g, 96%) as a
foamy solid. Rf = 0.29 (3:2 petroleum ether-EtOAc); [α]2D5 +184.2 (c 1.0, CHCl3); 1H-NMR (CDCl3): δ
8.08-7.26 (m, 20 H, Bz-H), 6.00 (dd, 1 H, J = 0.8, 3.3 Hz), 5.80-5.55 (m, 3 H), 4.96 (d, 1 H,
J = 7.9 Hz, H-1'), 4.70-4.30 (m, 6 H), 4.16-3.91 (m, 2 H), 2.56 (dd, 1 H, J = 6.7, 6.7 Hz), 1.44, 1.12 (s,
2 × 3 H, CH3); 13C-NMR (CDCl3): δ 166.1, 165.5, 165.5, 164.9 (4 C=O), 133.8, 133.6, 133.4, , 133.4,
130.1, 130.1, 130.0, 130.0, 129.8, 129.8, 129.7, 129.6, 129.2, 129.0, 128.9, 128.8, 128.7, 128.7, 128.7,
128.6, 128.5, 128.5, 128.3, 112.1, 104.9, 101.3 (2 × C-1), 83.6, 82.8, 79.8, 77.2, 72.1, 71.4, 69.6, 68.0,
62.2, 59.9, 26.9, 26.1; Anal. Calcd. for C42H40O14: C, 65.62; H, 5.24; found: C, 65.35; H, 5.37.
2,3,4,6-Tetra-O-benzoyl-β-D-galactopyranose-(1→3)-β-D-xylose (29). Compound 28 (1.22 g,
1.6 mmol) was dissolved in 4% aq H2SO4 (100 mL) and then refluxed for 4 h. TLC (1:1 petroleum
ether-EtOAc) indicated that the reaction was complete. The resulting soln. was cooled down to room
temperature and extracted three times with EtOAc. The extract was washed with saturated aq. sodium
bicarbonate, dried (Na2SO4) and concentrated. Purification by silica gel chromatography with 2:1
petroleum ether-EtOAc as the eluent afforded 29 (0.9 g, 85%) as a foamy solid. Rf = 0.31 (1:1
25
1
petroleum ether-EtOAc); [α]D +331.6 (c 1.0, CHCl3); H-NMR (CDCl3): δ 8.10-7.25 (m, 20 H, Bz-
H), 6.01 (d, 1 H, J = 3.3 Hz), 5.85 (m, 1 H), 5.65 (m, 1 H), 5.07-5.02 (m, 2 H), 4.58-4.40 (m, 3 H),
3.79-3.74 (m, 3 H), 3.50 (m, 1 H), 3.27 (m, 1 H); 13C-NMR (CDCl3): δ 166.1, 165.6, 165.5, 165.5 (4
C=O), 133.7, 133.5, 133.4, 133.4, 130.0, 130.0, 129.8, 129.7, 129.1, 129.0, 128.8, 128.8, 128.7, 128.6,
128.5, 128.5, 128.4, 128.3, 102.8, 102.6 (2 × C-1), 97.3, 92.4, 88.2, 85.7, 77.2, 73.4, 72.0, 71.5, 70.7,
70.0, 69.9, 68.2, 68.1, 62.4, 62.0; Anal. Calcd. for C39H36O14: C, 64.28; H, 4.98; found: C, 64.39;
H, 4.83.
2,3,4,6-Tetra-O-benzoyl-β-D-galactopyranose-(1→3)-2,4-di-O-benzoyl-β-D-xylopyranosyl trichloro-
acetimidate (15). Compound 29 (3.5 g, 4.8 mmol) was benzoylated under the same conditions as used
for the preparation of 19. Then the resultant residue was dissolved in 2 M MeOH-NH3 (200 mL) and
stirred at 35 °C at the end of which time TLC (3:1 petroleum ether-EtOAc) indicated that the reaction

Molecules 2011, 16
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was complete. The solvents were evaporated in vacuo at 50 °C to give a residue, which was dissolved
in CH2Cl2, and washed with water. The organic phase was dried (Na2SO4) and concentrated.
Purification by silica gel chromatography with 5:1 petroleum ether-EtOAc as the eluent afforded a
foamy residue. The residue was trichloroacetimidated under the same conditions as used for the
preparation of 10 from 19, giving 15 (3.5 g, 68% for three steps) as a white foamy solid. Rf = 0.42 (3:1
25
1
petroleum ether-EtOAc); [α]D +18.4 (c 0.5, CHCl3); H-NMR (CDCl3): δ 8.52 (s, 1 H, C=NH), 8.18-
7.08 (m, 30 H, Bz-H ), 6.54 (d, 1 H, J = 3.5 Hz), 5.87 (d, 1 H, J = 3.3 Hz), 5.66 (dd, 1 H, J = 7.9, 10.4
Hz), 5.48-5.37 (m, 2 H), 5.27 (dd, 1 H, J = 3.5, 9.7 Hz), 5.14 (d, 1 H, J = 7.9 Hz, H-1'), 4.67 (dd, 1 H,
J = 9.4, 9.4 Hz), 4.41-4.18 (m, 4 H), 3.95 (dd, 1 H, J = 10.9, 11.0 Hz). Anal. Calcd. for
C55H44Cl3NO16: C, 61.09; H, 4.10; N, 1.30; found: C, 61.34; H, 4.27; N, 1.49.
Benzyl oleanolate 3-O-4-O-allyl-2,3-di-O-benzoyl-α-L-rhamnopyranoside (30). Compound 10 (4.3 g,
7.8 mmol) and 9 [10] (3.6 g, 6.4 mmol) were coupled under the same conditions as used for the
preparation of 23 from 11 and 9, giving 30 (5.4 g, 88%) as a foamy solid. Rf = 0.45 (8:1 petroleum
25
1
ether-EtOAc); [α]D +73.7 (c 0.5, CHCl3); H-NMR (CDCl3): δ 8.06-7.31 (m, 15 H, Ar-H), 5.81 (m,
1 H, CH2=CH-CH2O), 5.66 (dd, 1 H, J = 3.2, 9.5 Hz, H-3'), 5.57 (dd, 1 H, J = 1.7, 3.2 Hz, H-2'), 5.29
(br s, 1 H, H-12), 5.20-5.03 (m, 4 H, PhCH2, CH2=CH-CH2O), 4.97 (d, 1 H, J1,2 = 1.7 Hz, H-1'), 4.22-
4.04 (m, 3 H), 3.67 (dd, 1 H, J = 9.5, 9.5 Hz, H-4'), 3.15 (dd, 1 H, J = 6.3, 9.8 Hz, H-3), 2.91 (dd, 1 H,
J = 4.1, 13.4 Hz, H-18), 1.40 (d, 3 H, J = 6.2 Hz, H-6'), 1.12, 1.02, 0.92, 0.92, 0.89, 0.88, 0.61 (s,
13
7 × 3H, CH3); C-NMR (CDCl3): δ 177.4, 165.5, 165.3 (3 C=O), 143.7, 136.4, 134.5, 133.2, 132.9,
130.0, 130.0, 129.9, 129.7, 129.5, 129.5, 128.4, 128.4, 128.4, 128.4, 128.3, 128.0, 128.0, 127.9, 122.5,
117.2, 99.6 (C-1'), 89.7, 79.1, 77.2, 74.0, 72.5, 71.5, 67.8, 65.9, 55.4, 47.6, 45.9, 41.7, 41.4, 39.3, 39.0,
38.4, 36.7, 33.9, 33.1, 32.7, 32.4, 30.7, 28.3, 27.6, 25.9, 25.3, 23.6, 23.4, 23.1, 18.3, 18.0, 16.9, 16.5,
15.3; Anal. Calcd. for C60H76O9: C, 76.56; H, 8.14; found: C, 76.73; H, 8.43.
Benzyl oleanolate 3-O-2,3-di-O-benzoyl-α-L-rhamnopyranoside (31). Compound 30 (5.0 g, 5.2 mmol)
was deallylated under the same conditions as that used for the preparation of 16 from 23, giving 31
(4.5 g, 94%) as a foamy solid; Rf = 0.16 (8:1 petroleum ether-EtOAc); [α]2D5 +29.5 (c 1.0, CHCl3); 1H-
NMR (CDCl3): δ 8.09-7.26 (m, 15 H, Ar-H), 5.57-5.48 (m, 2 H), 5.29 (br s, 1 H, H-12), 5.07 (dd, 2 H,
J = 12.6, 17.1 Hz, PhCH2), 5.00 (d, 1 H, J = 1.6 Hz, H-1'), 4.06-3.87 (m, 2 H), 3.18 (dd, 1 H,
J = 2.9, 13.0 Hz, H-3), 2.90 (dd, 1 H, J = 4.4, 14.2 Hz, H-18), 2.49 (d, 1 H, J = 5.1 Hz, OH), 1.41 (d,
3 H, J = 6.1 Hz, H-6'), 1.12, 1.01, 0.92, 0.92, 0.89, 0.87, 0.61 (s, 7 × 3 H, CH3); 13C-NMR (CDCl3): δ
177.4, 166.8, 165.6 (3 C=O), 143.6, 136.4, 133.3, 133.2, 129.7, 129.7, 129.7, 129.7, 129.5, 129.4,
128.4, 128.4, 128.3, 128.3, 127.9, 127.9, 127.9, 127.8, 126.8, 122.4, 99.7 (C-1'), 89.7, 73.4, 72.1, 71.3,
68.7, 65.9, 55.4, 47.5, 46.7, 45.8, 41.6, 41.4, 39.3, 38.9, 38.4, 36.7, 33.8, 33.0, 32.7, 32.3, 30.6, 28.3,
27.6, 25.8, 25.3, 23.6, 23.4, 23.0, 18.2, 17.5, 16.8, 16.5, 15.3; Anal. Calcd. for C57H72O9: C, 75.97; H,
8.05; found: C, 75.81; H, 8.29.
Oleanolic acid 3-O-α-L-rhamnopyranoside (1). A suspension of 31 (1.3 g, 1.4 mmol) and 10% Pd-C
(1.5 g) in EtOAc (30 mL) was refluxed and bubbled up with H2 (20 mL/min). When TLC (2:1,
petroleum-EtOAc) showed that the reaction had completed, Pd-C was removed through filtration and
the filtrate was concentrated to dryness. The resulted amorphous solid was dissolved in dry CH2Cl2-

Molecules 2011, 16
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MeOH (1:2, 30 mL), to which a newly prepared NaOMe/MeOH (1.0 mol/L, 20 mL) was added. The
soln was stirred at rt for 2 h and then neutralized with Dowex H+ resin to pH 7 and filtered. The filtrate
was concentrated and subjected to a flash column chromatography (CHCl3-MeOH-H2O 7:3:1, organic
layer) to give 1 [13] (737 mg, 86% for two steps) as a white powder.
Oleanolic acid 3-O-6-deoxy-α-L-talopyranoside (2). Compound 2 was prepared from 16 by the same
procedure as for 1. Yield: 81%; white powder, m.p. 288-290 °C, Rf = 0.29 (10:1:0.1 CHCl3-MeOH-
H2O); [α]2D5 +6.1 (c 0.5, MeOH); H-NMR (pyridine-d5): δ 5.47 (br s, 1 H, H-12), 5.31 (d, 1 H,
1
J = 1.3 Hz, H-1'), 4.85 (dd, 1 H, J = 1.5, 3.0 Hz, H-2'), 4.25-4.21 (m, 2 H), 4.06 (d, 1 H, J = 1.4 Hz),
3.29 (dd, 1 H, J = 4.0, 13.7 Hz, H-3), 3.13 (dd, 1 H, J = 4.3, 11.5 Hz, H-18), 1.54 (d, 3 H, J = 6.5 Hz,
H-6'), 1.28, 1.00, 0.99, 0.95, 0.90, 0.85, 0.80 (s, 7 × 3 H, CH3); 13C-NMR (pyridine-d5): δ 180.2, 144.9,
122.6, 104.9 (C-1'), 88.6, 74.3, 72.4, 67.8, 67.5, 55.7, 48.1, 46.7, 46.6, 42.2, 42.1, 39.8, 39.2, 38.6,
37.1, 34.3, 33.4, 33.3, 33.2, 31.0, 28.4, 28.3, 26.2, 25.8, 23.9, 23.9, 23.8, 18.7, 17.5, 17.4, 16.8, 15.5;
HRESIMS: m/z calcd. for C36H58O7Na[M+Na+]: 625.4080; found: m/z 625.4059.
Benzyl oleanolate 3-O-2,3,4,6-tetra-O-benzoyl-β-D-galactopyranoside (34). Compound 12 (0.56 g,
0.8 mmol) and 9 [15] (0.6 g, 0.7 mmol) were coupled under the same conditions as that used for the
preparation of 23 from 11 and 9, giving 34 [13] (0.9 g, 90%) as a foamy solid.
Oleanolic acid 3-O-β-D-galactopyranoside (3). Compound 3 [13] was prepared from 34 by the same
procedure as for 1. Yield: 84%; white powder.
Benzyl oleanolate 3-O-2,3,4,6-tetra-O-acetyl-α-D-mannopyranoside (36). Compound 13 [12] (1.5 g,
3.0 mmol) and 9 [10] (1.4 g, 2.5 mmol) were coupled under the same conditions as used for the
preparation of 23 from 11 and 9, giving 36 (1.9 g, 86%) as a foamy solid. Rf = 0.16 (6:1 petroleum
25
1
ether-EtOAc); [α]D +70.6 (c 0.5, CHCl3); H-NMR (CDCl3): δ 7.47-7.27 (m, 5 H, Bn-H), 5.35-5.24
(m, 3 H), 5.16-5.06 (m, 3 H), 4.97 (d, 1 H, J = 1.7 Hz, H-1'), 4.25 (dd, 1 H, J = 5.7, 12.5 Hz, H-3),
4.15-4.10 (m, 2 H), 3.21 (dd, 1 H, J = 4.0, 11.3 Hz, H-3), 2.90 (dd, 1 H, J = 4.0, 13.6 Hz, H-18), 2.16,
13
2.09, 2.05, 2.00 (s, 4 × 3 H, CH3CO), 1.11, 1.00, 0.92, 0.89, 0.89, 0.82, 0.60 (s, 7 × 3 H, CH3); C-
NMR (CDCl3): δ 177.4, 170.6, 170.2, 169.9, 169.8 (5 C=O), 143.6, 136.3, 128.3, 128.3, 127.9, 127.9,
122.4, 94.6 (C-1'), 84.7, 77.2, 70.7, 69.2, 69.0, 66.4, 66.3, 65.9, 62.6, 55.6, 47.6, 46.7, 45.8, 41.6, 41.3,
39.3, 38.3, 38.0, 36.8, 33.8, 33.0, 32.7, 32.3, 30.6, 28.7, 27.6, 25.8, 23.6, 23.4, 23.0, 22.1, 20.8, 20.6,
20.6, 18.2, 16.8, 16.4, 15.2; HRESIMS: m/z calcd. for C51H72O8Na[M+Na+]: 835.5125; found: m/z
835.5118.
Oleanolic acid 3-O-α-D-mannopyranoside (4). Compound 4 was prepared from 36 by the same
procedure as for 1. Yield: 87%; white powder, m.p. 250-252 °C, Rf = 0.07 (20:1:0.1 CHCl3-MeOH-
H2O); [α]2D5 +79.8 (c 0.5, MeOH); 1H-NMR (pyridine-d5): δ 5.54 (d, 1 H, J = 1.0 Hz, H-1'), 5.46 (br s,
1 H, H-12), 4.69 (m, 1 H), 4.59-4.50 (m, 3 H), 4.46-4.38 (m, 2 H), 3.47 (dd, 1 H, J = 4.2, 11.4 Hz, H-
3), 3.28 (dd, 1 H, J = 4.0, 13.5 Hz, H-18), 1.24, 1.15, 1.00, 0.97, 0.94, 0.81, 0.79 (s, 7 × 3 H, CH3);
13C-NMR (pyridine-d5): δ 180.1 (C=O), 144.8, 124.1, 122.4, 97.7 (C-1'), 81.8, 75.8, 73.2, 72.9, 69.2,
63.4, 55.7, 47.9, 46.6, 46.4, 42.1, 41.9, 39.7, 38.5, 38.1, 37.1, 34.2, 33.2, 33.1, 33.1, 30.9, 29.0, 28.2,

Molecules 2011, 16
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26.1, 23.7, 23.6, 22.0, 18.5, 17.3, 16.9, 15.3; HRESIMS: m/z calcd. for C36H58O8Na[M+Na+]:
641.4029; found: m/z 641.4037.
Benzyl oleanolate 3-O-2,3,4-tri-O-benzoyl-β-D-xylopyranosyl-(1→4)-2,3-di-O-benzoyl-6-deoxy-α-L-
talopyranoside (38). Compound 16 (1.1 g, 1.3 mmol) and 14 [13] (0.9 g, 1.5 mmol) were coupled
under the same conditions as that used for the preparation of 23 from 11 and 9, giving 38 (1.4 g, 90%)
as a foamy solid. Rf = 0.13 (8:1 petroleum ether-EtOAc); [α]2D5 -24.6 (c 0.5, CHCl3); 1H-NMR (CDCl3):
δ 8.33-7.26 (m, 30 H, Ar-H), 5.67 (dd, 1 H, J = 8.2, 9.1 Hz, H-2''), 5.58 (dd, 1 H, J = 6.7, 9.1 Hz, H-3''),
5.48 (d, 1 H, J = 2.2 Hz, H-1'), 5.40 (dd, 1 H, J = 3.6, 3.6 Hz, H-3'), 5.28 (br s, 1 H, H-12), 5.07 (dd, 2
H, J = 12.5, 17.6 Hz, PhCH2), 4.98-4.92 (m, 2 H), 4.70 (d, 1 H, J = 6.7 Hz, H-1''), 4.29-4.19 (m, 2 H),
3.50 (m, 1 H), 3.14-3.04 (m, 2 H), 2.89 (dd, 1 H, J = 4.1, 9.6 Hz, H-18), 1.19 (d, 3 H, J = 6.5 Hz, H-6'),
13
1.10, 0.97, 0.91, 0.89, 0.89, 0.81, 0.59 (s, 7 × 3 H, CH3); C-NMR (CDCl3): δ 177.4, 166.3, 166.2,
165.6, 165.2, 164.9 (6 C=O), 143.7, 140.9, 138.8, 136.4, 133.3, 133.2, 133.1, 133.0, 130.4, 130.0,
130.0, 129.9, 129.8, 129.7, 129.2, 129.1, 128.6, 128.5, 128.4, 128.4, 128.3, 128.3, 128.3, 128.0, 127.9,
127.8, 127.6, 127.5, 126.9, 122.4, 103.1, 100.7 (2 × C-1), 99.4, 89.5, 78.1, 77.3, 76.6, 76.4, 74.2, 73.7,
72.8, 72.3, 71.8, 71.6, 69.9, 68.6, 68.3, 65.9, 65.6, 65.3, 62.1, 60.2, 55.5, 55.4, 47.5, 46.7, 45.9, 41.7,
41.4, 39.3, 38.9, 38.4, 36.7, 33.1, 32.4, 30.7, 28.3, 27.6, 25.8, 23.6, 23.4, 23.1, 18.2, 16.9, 16.5, 16.1,
15.3; HRESIMS: m/z calcd. for C83H92O16Na[M+Na+]: 1367.6283; found: m/z 1367.6290.
Oleanolic acid 3-O-β-D-xylopyranosyl-(1→4)-6-deoxy-α-L-talopyranoside (5). Compound 5 was
prepared from 38 by the same procedure as for 1. Yield: 71%; white powder, m.p. 218-220 °C,
Rf = 0.11 (10:1:0.1 CHCl3-MeOH-H2O); [α]2D5 -30.7 (c 0.5, MeOH); 1H-NMR (pyridine-d5): δ 5.47 (br
s, 1 H, H-12), 5.27 (s, 1 H, H-1'), 4.80 (d, 1 H, J = 7.4 Hz, H-1''), 4.34-4.30 (m, 2 H), 4.25-4.20 (m,
3 H), 4.13-3.93 (m, 3 H), 3.69 (dd, 1 H, J = 9.6, 10.9 Hz), 3.29 (dd, 1 H, J = 3.9, 13.6 Hz, H-3), 3.11
(dd, 1 H, J = 4.3, 11.6 Hz, H-18), 1.70 (d, 3 H, J = 6.6 Hz, H-6'), 1.29, 1.00, 1.00, 0.95, 0.92, 0.84, 0.79
(s, 7 × 3 H, CH3); 13C-NMR (pyridine-d5): δ 180.1 (C=O), 144.8, 122.4, 106.3, 104.9 (2 × C-1), 88.6,
83.3, 77.8, 74.7, 71.9, 70.5, 67.2, 67.1, 66.7, 55.5, 47.9, 46.6, 46.4, 42.1, 42.0, 39.7, 39.1, 38.4, 36.9,
34.2, 33.2, 33.2, 33.1, 30.9, 28.2, 26.1, 25.6, 23.7, 23.7, 23.7, 23.6, 18.5, 17.3, 17.0, 16.6, 15.4;
HRESIMS: m/z calcd. for C41H66O11Na[M+Na+]: 757.4503; found: m/z 757.4515.
Benzyl oleanolate 3-O-2,3,4,6-tetra-O-benzoyl-β-D-galactopyranosyl-(1→4)-2,3-di-O-benzoyl-α-L-
rhamnopyranoside (40). Compound 12 [11] (0.9 g, 1.2 mmol) and 31 (0.9 g, 1.0 mmol) were coupled
under the same conditions as that used for the preparation of 23 from 11 and 9, giving 40 (1.3 g, 89%)
as a foamy solid. Rf = 0.07 (8:1 petroleum ether-EtOAc); [α]2D5 +64.5 (c 0.5, CHCl3); H-NMR
1
(CDCl3): δ 8.07-7.05 (m, 35 H, Ar-H), 5.97 (d, 1 H, J = 3.1 Hz, H-4''), 5.75 (dd, 1 H, J = 7.9, 10.4 Hz,
H-2''), 5.55-5.47 (m, 2 H, H-2', H-3'), 5.41 (dd, 1 H, J = 3.3, 10.4 Hz, H-3''), 5.30 (br s, 1 H, H-12),
5.13-5.07 (m, 3 H, H-1'', PhCH2), 4.94 (d, 1 H, J = 1.4 Hz, H-1'), 4.71-4.37 (m, 3 H), 4.21-4.05 (m,
2 H), 3.14 (dd, 1 H, J = 7.5, 8.6 Hz, H-3), 2.91 (dd, 1 H, J = 3.9, 13.7 Hz, H-18), 1.50 (d, 1 H,
J = 6.0 Hz, H-6'), 1.12, 0.96, 0.92, 0.92, 0.89, 0.85, 0.61 (s, 7 × 3 H, CH3); 13C-NMR (CDCl3): δ 177.4,
166.1, 165.5, 165.4, 165.4, 165.3, 164.7 (7 C=O), 143.7, 136.4, 133.5, 133.3, 133.2, 133.1, 132.8,
129.9, 129.7, 129.7, 129.7, 129.6, 129.6, 129.6, 129.6, 129.6, 129.5, 129.5, 129.4, 129.3, 129.0, 128.8,

Molecules 2011, 16
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128.6, 128.6, 128.5, 128.5, 128.4, 128.4, 128.4, 128.4, 128.4, 128.4, 128.4, 128.4, 128.3, 128.2, 128.1,
128.0, 128.0, 128.0, 128.0, 127.9, 122.5, 101.5, 99.8 (2 × C-1), 89.9, 77.6, 77.2, 72.5, 71.9, 71.1, 70.9,
69.7, 68.0, 67.1, 65.9, 62.0, 55.4, 47.6, 46.7, 45.9, 41.7, 41.4, 39.3, 38.9, 38.5, 36.7, 33.8, 33.0, 32.7,
32.4, 30.6, 28.3, 27.6, 25.8, 25.4, 23.6, 23.4, 23.1, 18.2, 18.1, 16.8, 16.5, 15.3; HRESIMS: m/z calcd.
for C91H98O18Na[M+Na+]: 1501.6651; found: m/z 1501.6629.
Oleanolic acid 3-O-β-D-galactopyranosyl-(1→4)-α-L-rhamnopyranoside (6). Compound 6 was
prepared from 40 by the same procedure as for 1. Yield: 68%; white powder, m.p. 268-270 °C,
Rf = 0.70 (10:2:0.1 CHCl3-MeOH-H2O); [α]2D5 +24.6 (c 0.5, MeOH); 1H-NMR (pyridine-d5): δ 5.46 (br
s, 1 H, H-12), 5.27 (s, 1 H, H-1'), 5.18 (d, 1 H, J = 7.8 Hz, H-1''), 4.60-4.24 (m, 8 H), 4.14 (dd, 1 H,
J = 3.4, 9.5 Hz), 3.95 (dd, 1 H, J = 6.1, 6.4 Hz, H-2''), 3.29 (dd, 1 H, J = 4.2, 13.7 Hz, H-3), 3.11 (dd, 1
H, J = 4.5, 11.6 Hz, H-18),1.74 (d, 3 H, J = 6.2 Hz, H-6'), 1.27, 1.00, 0.99, 0.95, 0.89, 0.83, 0.76 (s,
13
7 × 3 H, CH3); C-NMR (pyridine-d5): δ 180.1 (C=O), 144.8, 122.7, 122.5, 107.3, 103.9 (2 × C-1),
88.5, 85.2, 76.9, 75.6, 74.1, 72.9, 71.9, 70.0, 68.1, 62.0, 55.5, 47.9, 46.6, 46.4, 42.1, 42.0, 39.7, 39.1,
38.4, 36.9, 34.2, 33.2, 33.2, 33.1, 30.9, 28.3, 28.2, 26.1, 25.7, 23.7, 23.7, 18.5, 18.3, 17.3, 16.7, 15.4;
HRESIMS: m/z calcd. for C42H68O12Na[M+Na+]: 787.4608; found: m/z 787.4579.
Benzyl oleanolate 3-O-2,3,4,6-tetra-O-benzoyl-β-D-galactopyranosyl-(1→3)-2,4-di-O-benzoyl-β-D-
xylopyranosyl-(1→4)-2,3-di-O-benzoyl-6-deoxy-α-L-talopyranoside (42). Compound 16 (0.3 g,
0.3 mmol) and 15 (0.41 g, 0.4 mmol) were coupled under the same conditions as used for the
preparation of 23 from 11 and 9, giving 42 (0.5 g, 90%) as a foamy solid. Rf = 0.11 (4:1 petroleum
25
1
ether-EtOAc); [α]D -26.6 (c 0.5, CHCl3); H-NMR (CDCl3): δ 8.28-7.16 (m, 45 H, Ar-H), 5.78 (d,
1 H, J = 3.5 Hz), 5.59 (dd, 1 H, J = 7.9, 10.4 Hz), 5.47-5.41 (m, 2 H), 5.26-5.20 (m, 2 H), 5.06 (dd,
2 H, J = 12.5, 17.3 Hz, PhCH2), 4.93-4.86 (m, 3 H), 4.44 (d, 1 H, J = 1.4 Hz), 4.39-3.92 (m, 6 H), 3.30
(dd, 1 H, J = 5.6, 12.1 Hz, H-3), 3.06-2.87 (m, 3 H), 0.99 (d, 1 H, J = 6.5 Hz, H-6'), 1.09, 0.93, 0.91,
0.89, 0.86, 0.77, 0.58 (s, 7 × 3 H, CH3); 13C-NMR (CDCl3) δ 177.4, 166.3, 166.2, 165.8, 165.4, 165.3,
165.0, 164.9, 163.9 (9 C=O), 143.7, 136.4, 133.3, 133.3, 133.3, 133.2, 133.2, 133.1, 133.0, 132.9,
130.5, 130.0, 129.9, 129.9, 129.8, 129.8, 129.7, 129.7, 129.7, 129.7, 129.7, 129.7, 129.6, 129.6, 129.6,
129.5, 129.5, 129.4, 129.4, 129.4, 129.4, 129.2, 129.0, 128.7, 128.6, 128.5, 128.5, 128.5, 128.5, 128.5,
128.4, 128.4, 128.4, 128.4, 128.4, 128.4, 128.3, 128.3, 128.2, 128.2, 128.1, 128.0, 127.9, 127.9, 127.8,
127.8, 122.4, 103.3, 101.0, 100.6 (3 × C-1), 89.3, 77.3, 73.2, 71.7, 70.9, 70.2, 69.7, 68.5, 68.0, 67.5,
65.9, 65.4, 62.4, 61.2, 55.3, 47.5, 46.7, 45.9, 41.7, 41.4, 39.3, 38.9, 38.3, 36.6, 33.8, 33.0, 32.6, 32.3,
30.6, 28.2, 27.6, 25.8, 25.1, 23.6, 23.3, 23.0, 18.2, 16.8, 16.4, 15.9, 15.3; HRESIMS: m/z calcd. for
C110H114O24Na[M+Na+]: 1841.7598; found: m/z 1841.7579.
Oleanolic
acid
3-O-β-D-galactopyranosyl-(1→3)-β-D-xylopyranosyl-(1→4)-6-deoxy-α-L-talo-
pyranoside (7). Compound 7 was prepared from 42 by the same procedure as for 1. Yield: 75%; white
25
1
powder, m.p. 202-204 °C, Rf = 0.82 (10:2:0.1 CHCl3-MeOH-H2O); [α]D -36.8 (c 0.5, MeOH); H-
NMR (pyridine-d5): δ 5.47 (br s, 1 H, H-12), 5.27-5.25 (m, 2 H), 4.72 (d, 1 H, J = 7.8 Hz), 4.54-4.50
(m, 2 H), 4.40-3.91 (m, 12 H), 3.85 (dd, 1 H, J = 7.0, 7.0 Hz), 3.59 (dd, 1 H, J = 10.2, 11.2 Hz), 3.28
(dd, 1 H, J = 4.2, 10.0 Hz, H-3), 3.09 (dd, 1 H, J = 4.4, 11.4 Hz, H-18), 1.67 (d, 3 H, J = 6.5 Hz, H-6'),

Molecules 2011, 16
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1.28, 1.00, 0.99, 0.95, 0.90, 0.83, 0.78 (s, 7 × 3 H, CH3); 13C-NMR (pyridine-d5): δ 180.2, 144.9,
122.5, 106.3, 105.9, 104.9 (3 × C-1), 88.8, 86.8, 83.6, 77.3, 75.2, 73.5, 73.1, 72.0, 70.2, 69.0, 67.1,
66.7, 66.5, 62.1, 57.4, 55.6, 48.0, 46.7, 46.5, 42.2, 42.1, 39.8, 39.2, 38.5, 37.0, 34.3, 33.3, 33.2, 31.0,
28.4, 28.3, 26.2, 25.7, 23.8, 23.7, 19.2, 18.6, 17.4, 17.0, 16.8, 15.5; HRESIMS: m/z calcd. for
C47H76O16Na[M+Na+]: 919.5031; found: m/z 919.5018.
3.3. Fungicidal activity bioassay
We used the mycelium growth rate test [20]. The culture media, with known concentration of the
test compounds, were obtained by mixing the soln of compounds 1-7 in methanol with potato dextrose
agar (PDA), on which fungus cakes were placed. The blank test was made using methanol. The culture
was carried out at 24 ± 0.5 °C. Three replicates were performed.
4. Conclusions
Seven glycoconjugates of oleanolic acid were designed and efficiently synthesized. The bioassays
showed that they had some fungicidal activity against four fungi. All of the compounds exhibited more
fungicidal activity against R. solani, and the compounds 1 and 2 had better activity against B. cinerea
and P. CapasiciLeonian than the other compounds.
Acknowledgements
This work was supported by the NSFC (No. 20902108) of China, National Basic Research Program
of China (No. 2010CB126105), and the National Scientific & Technical Supporting Programs (No.
2009BAK61B04).
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Sample Availability: Samples of the compounds are available from the authors.
© 2011 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article
distributed under the terms and conditions of the Creative Commons Attribution license
(http://creativecommons.org/licenses/by/3.0/).