Synthesis and antitumour activity of glycyrrhetinic acid derivatives

Article abstract of DOI:10.1016/j.bmc.2010.08.054

Glycyrrhetinic acid (GA) is one of many interesting triterpenoic acids showing anticancerogenic potential. GA is known to trigger apoptosis in tumour cell lines, although GA has a low cytotoxicity. In our study we were able to prepare derivatives of GA that show lowered the IC₅₀ values as determined by a sulforhodamine B (SRB) assay using 15 different human tumour cell lines. Thus, combining an ester group combined with the presence of an amino acid moiety led to a ca. 60-fold improved antitumor activity. Experiments on mouse embryonic fibroblasts (NiH3T3) revealed that these compounds showed a better selectivity for tumour cells compared to the parent compound GA. An apoptotic effect of some of these compounds was determined using an acridine orange/ethidium bromide (AO/EB) test and DNA laddering experiments.

Full text of DOI:10.1016/j.bmc.2010.08.054

Bioorganic & Medicinal Chemistry 18 (2010) 7458–7474
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
Synthesis and antitumour activity of glycyrrhetinic acid derivatives
⇑
Stefan Schwarz, René Csuk
Bereich Organische Chemie, Martin-Luther-Universität Halle-Wittenberg, Kurt-Mothes-Str. 2, D-06120 Halle, Saale, Germany
a r t i c l e i n f o
a b s t r a c t
Article history:
Glycyrrhetinic acid (GA) is one of many interesting triterpenoic acids showing anticancerogenic potential.
GA is known to trigger apoptosis in tumour cell lines, although GA has a low cytotoxicity. In our study we
were able to prepare derivatives of GA that show lowered the IC50 values as determined by a sulforhoda-
mine B (SRB) assay using 15 different human tumour cell lines. Thus, combining an ester group combined
with the presence of an amino acid moiety led to a ca. 60-fold improved antitumor activity. Experiments
on mouse embryonic fibroblasts (NiH3T3) revealed that these compounds showed a better selectivity for
tumour cells compared to the parent compound GA. An apoptotic effect of some of these compounds was
determined using an acridine orange/ethidium bromide (AO/EB) test and DNA laddering experiments.
Ó 2010 Elsevier Ltd. All rights reserved.
Received 30 June 2010
Revised 10 August 2010
Accepted 29 August 2010
Available online 18 September 2010
Keywords:
Glycyrrhetinic acid
SRB assay
Acridine orange/ethidium bromide assay
Apoptosis
Antitumour
1. Introduction
presence of potassium carbonate.7 We were able to synthesize
the tert-butyl ester, too. However, this compound is unstable
Glycyrrhetinic acid (GA) is not the most potent antitumour active
triterpenoic acid; several other triterpenes, for example, betulinic
acid,1–3 are better known for their antitumour activity. GA, however,
is still of special interest because of its apoptotic effect on to tumour
cells. In addition, the extract of the licorice roots contains up to 24%
GA—mainly as glycosidic glycyrrhizic acid.4 Therefore, compared to
other triterpenoic acids, GA can be obtained cheaper and in a higher
amount than, for example, betulinic acid (2.44%,5 3.3%6) or oleanoic
acid (3.1%5). Improving the antitumour activity of GA without for-
feiting its apoptotic effect is one of the big challenges when dealing
with the derivatization of GA. We thought that changing the polarity
pattern of the molecule might be of some interest; introducing an
extra amino group (for gain of polarity) and preparing esters of GA
(for gain of lipophilicity) seemed appropriate.
Thus, we synthesized 25 derivatives of GA—esterified at C(30) and
varied by coupling with an amino acid at C(3)—and compared their
biological activity (IC50 values) using a sulforhodamine B assay (SRB
assay) with up to 15 human tumour cell lines and mouse embryonic
fibroblasts NiH3T3; extra acridine orange/ethidium bromide tests
(AO/EB) were performed to test for an apoptotic behaviour.
under the conditions of the SRB assay test and was excluded from
this study.
In the SRB assay the esters showed an improved activity on
to tumour cell lines (Fig. 2, left and Table 1). The most active
substance was the benzyl ester showing IC50 values between
2.7–25.2 lM. The toxicity of these compounds for the mouse
embryonic fibroblasts remained almost constant throughout
this series (Fig. 2, right) except for the i-propyl ester that
shows a lowered activity; the decrease in the IC50 values paral-
lels the size and lipophilic character of the alkyl chain of the
ester.
As far as GA is concerned, we found a more than four times
higher toxicity on mouse embryonic fibroblasts than on tumour
cell lines. A maximum of selectivity towards the tumour cells,
however, was established for compound 4; this derivative is
approx. eight times more toxic for the SW1736 thyroid carci-
noma (IC50 = 2.74 lM) than for the fibroblasts (IC50 = 21.02 lM).
2. Results
2.1. Influence of an ester moiety
Different esters of GA differing in the alcoholic part (Fig. 1)
were prepared by reacting GA with alkyl halides in DMF in the
⇑
Corresponding author. Tel.: +49 345 55 25660; fax: +49 345 55 27030.
E-mail address: rene.csuk@chemie.uni-halle.de (R. Csuk).
Figure 1. Esters of GA: 1: R = Me; 2 R = Et; 3: R = i-Pr; 4: R = Bn.
0968-0896/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2010.08.054

S. Schwarz, R. Csuk / Bioorg. Med. Chem. 18 (2010) 7458–7474
7459
100
80
60
40
20
0
Tumour cells
Fibroblasts
Figure 3. Amino acid derivatives of GA and of GA esters.
A priori, a dependency between biological activity and a coun-
ter-ion cannot be ruled out. Thus, to find out that the biological
data obtained from amines and their respective ammonium hydro-
chlorides are comparable, we checked whether there is a difference
in their cytotoxic activity. As a representative example, the methyl
esters of the amino acid derivatives were investigated; the results
from the SRB assay are compiled in Table 4.
GA
1
2
3
4
Figure 2. IC50 values (in lM) for GA and its esters 1–4 for tumour cells (averaged,
15 cell lines) and mouse fibroblastic cells (NiH3T3).
These results suggest there is no significant difference in the
biological activity between amines and their respective ammo-
nium salts.
2.2. Amino acid derivatives of GA
As far as the N-Boc protected derivatives are concerned, three
derivatives (23–25) were tested in the SRB assay; all of them gave
an IC50 >30 lmol.
In this series of compounds we introduced a polar proton accep-
tor group in position C(3). These compounds were synthesized by
DCC mediated esterifications of N-Boc protected amino acids (gly-
cine, D-alanine and b-alanine) followed by their deprotection using
TFA in dry DCM8 (for the amines) or by treating them with dry HCl
gas in DCM (for the ammonium hydrochlorides).
2.3. Influence of a stereogenic centre
For all esters (Tables 2 and 3 and Fig. 4), activity increases when
C(3) is substituted with one of the three amino acids. In this series,
the glycine substituted i-propyl ester was shown the most active
compound; the ethyl ester, however, is the most active compound
To work out if the stereogenic centre introduced in the amino
acid derivatives of GA has any influence on the biological activity
several derivatives containing a
and compared (SRB assay, 15 different tumour cell lines) with their
respective -alaninyl diastereomers. The data for this series are
D-alaninyl residue were prepared
L
when a L-alaninyl or a b-alaninyl substituent was introduced.
summarized in Table 5. In summary, the effect of the stereogenic
centre is small and varies with the cell lines.
Interestingly enough, in this series of compounds the derivatives
of b-alanine show the highest activity except for 14. On average,
the lowest IC50 values were obtained for 16 (substituted with
i-propyl and b-alanine). All derivatives holding a free carboxylic
2.4. Apoptotic study using the AO/EB test and DNA laddering
group in position C(30) gave IC50 values >30
from further investigations.
From the selected amino acids, the derivatives of b-alanine
show the highest activity. The sole exception is derivative 14 (av
lM and were excluded
As previously shown,9–12 GA induces apoptosis. To prove
whether this feature remains or is lost on derivatization, we tested
four compounds for an induction of apoptosis in an AO/EB test.
Figure 5 (left) depicts a section of A549 cells after being treated
with GA. As expected, the cells showed apoptotic behaviour; this
can easily be seen from the green fluorescence of the nucleus.
The more active compounds 8–10 and 25 were investigated in
the same way. In all of these samples, apoptotic cells were
detected. Although this assay doesn’t allow to quantify the ratio
2.49 lM), substituted with glycine and esterified with i-propyl.
The lowest average of the IC50 value we determined was for sub-
stance 16, substituted with i-propyl and b-alanine. All derivatives
having a free carboxyl group in position C(30) gave IC50 values
higher than 30
investigations.
lM; thus, they were excluded from further
Table 1
Results from the SRB assay for esters of glycyrrhetinic acid (results given in
lM)
Derivative/cell line
GA
1
2
3
4
518A2
8505C
A253
A2780
A431
A549
DLD-1
FaDu
HCT-116
HCT-8
HT-29
Lipo
MCF-7
SW1736
SW480
Average
NiH3T3
83.92 4.20
86.50 4.33
80.78 4.04
74.57 3.73
79.58 3.99
82.76 4.14
81.21 4.06
84.55 4.23
78.83 3.94
78.85 3.94
80.09 4.00
81.44 4.07
84.70 4.24
76.93 3.85
86.80 4.34
81.43 4.07
18.52 0.93
27.54 1.38
26.07 1.30
19.42 0.97
25.54 1.28
25.28 1.26
23.50 1.18
26.12 1.31
23.41 1.17
22.10 1.11
24.36 1.22
27.54 1.38
20.47 1.02
22.14 1.11
34.87 1.74
16.08 0.80
24.30 1.22
22.81 1.14
25.23 1.26
24.58 1.23
25.04 1.25
26.96 1.35
23.45 1.17
22.74 1.14
28.14 1.41
23.76 1.19
21.58 1.08
43.42 2.17
22.14 1.11
27.66 1.38
18.61 0.93
13.37 0.67
19.10 0.96
24.39 1.22
23.66 1.18
18.15 0.91
14.24 0.71
15.76 0.79
24.95 1.25
32.01 1.60
14.41 0.72
27.61 1.38
14.42 0.72
26.44 1.32
24.12 1.21
15.97 0.80
15.93 0.80
16.04 0.80
12.77 0.64
15.33 0.77
19.21 0.96
32.37 1.62
18.19 0.91
8.10 0.41
10.67 0.54
20.32 1.02
23.58 1.18
6.15 0.31
22.69 1.13
5.48 0.27
20.57 1.03
25.23 1.26
11.48 0.57
11.54 0.58
13.49 0.67
2.74 0.14
6.17 0.31
13.76 0.69
21.02 1.05

7460
S. Schwarz, R. Csuk / Bioorg. Med. Chem. 18 (2010) 7458–7474
Table 2
Modifications of GA at positions C(3) and C(30)
Compd
5
6
7
8
9
10
11
12
13
R1
R2
GlyꢀHCl
b-AlaꢀHCl
Gly
b-Ala
Gly
b-Ala
L
-AlaꢀHCl
L
-Ala
L
-Ala
H
H
15
H
Me
17
Me
18
Me
19
Et
20
Et
21
Et
22
14
16
R1
R2
Gly
b-Ala
i-Pr
Gly
Bn
b-Ala
GlyꢀHCl
Me
b-AlaꢀHCl
Me
L
-Ala
L
-Ala
L
-AlaꢀHCl
i-Pr
i-Pr
Bn
Bn
Me
Table 3
IC50 values (in
l
M) for GA derivatives substituted with amino acids in position C(3) and esterified in C(30) (Fig. 3)
Cell lines/derivatives
8505C
A253
A2780
A549
DLD-1
Lipo
Average
5
6
>30
>30
>30
>30
>30
>30
>30
>30
>30
>30
>30
>30
>30
>30
7
>30
>30
>30
>30
>30
>30
>30
8
9
7.45 0.37
4.31 0.22
2.55 0.13
5.32 0.27
3.87 0.19
2.32 0.12
2.76 0.14
3.49 0.17
1.96 0.10
4.79 0.24
3.10 0.16
3.19 0.16
6.26 0.31
3.61 0.18
2.50 0.13
3.59 0.18
2.33 0.12
2.23 0.11
2.01 0.10
3.51 0.18
2.68 0.13
5.03 0.25
3.49 0.17
3.05 0.15
5.99 0.30
2.98 0.15
1.72 0.09
3.90 0.20
2.59 0.13
1.77 0.09
2.24 0.11
2.08 0.10
1.31 0.07
3.54 0.18
2.85 0.14
1.73 0.09
6.42 0.32
2.77 0.14
2.40 0.12
5.39 0.27
3.43 0.17
2.18 0.11
2.65 0.13
3.43 0.17
1.78 0.09
5.07 0.25
3.51 0.18
2.76 0.14
8.59 0.43
4.49 0.22
2.51 0.13
5.61 0.28
3.72 0.19
2.74 0.14
2.54 0.13
5.54 0.28
3.52 0.18
4.54 0.23
5.02 0.25
4.54 0.23
7.54 0.38
4.30 0.22
2.52 0.13
4.32 0.22
2.74 0.14
2.38 0.12
2.74 0.14
3.53 0.18
3.49 0.17
4.81 0.24
3.57 0.18
3.25 0.16
7.04 0.35
3.74 0.19
2.37 0.12
4.69 0.23
3.11 0.16
2.27 0.11
2.49 0.12
3.60 0.18
2.46 0.12
4.63 0.23
3.59 0.18
3.09 0.15
10
11
12
13
14
15
16
17
18
19
During apoptosis DNA is cleaved13–15 into smaller fragments by
endonucleases. These fragments are observable by gel electropho-
resis as ladders. Thus, the floating cells (obtained after treatment
with IC90-concentrations for 24 h) were analyzed by DNA gel elec-
trophoresis and the typical DNA ladders were observed. Some of
these results are depicted in Figure 6.
30
25
20
15
10
5
Gly
L-Ala
β-Ala
3. Conclusion
In this study we were able to synthesize simple derivatives of
GA; these compounds, however, showed an increased cytotoxicity
for various human cancer cell lines. For several of these derivatives
the selectivity index was increased, too. These results point out
there is an increasing activity with increasing lipophilicity for GA
esters. This tendency, however, is not found for derivatives
substituted with an extra amino acid moiety. An unsubstituted
0
acid
methyl
ethyl
i-propyl
benzyl
Figure 4. IC50 values (in lM) for the amino acid modified GA derivatives (averaged
values, six tumour cell lines).
carboxylic group in C(30) led to inactive (IC50 >30 lM) compounds;
the same is true for N-Boc protected amino acid derivatives. The
presence of an added stereogenic centre in the side chain seems
not important for activity. Previously, numerous modifications16
in the ring skeleton of GA have been reported. With respect to ring
A modifications, most approaches have focused on the synthesis of
C2 and/or C-3 modified derivatives. Some C-3 ester17 and a
between apoptotic and necrotic cells, the ability of the compounds
to trigger apoptosis is displayed unambiguously. Figure 5 (left to
right) show sections from the samples showing the characteristic
green fluorescent nucleus.
Table 4
SRB data for selected amines and their hydrochlorides (IC50 in
lM)
Derivative/cell line
9 amine
21 hydrochloride
8 amine
20 hydrochloride
10 amine
22 hydrochloride
518A2
8505C
A253
A2780
A549
DLD-1
Lipo
MCF-7
SW1736
Average
3.54 0.18
4.31 0.22
3.61 0.18
2.98 0.15
2.77 0.14
4.49 0.22
4.30 0.22
3.54 0.18
3.22 0.16
3.64 0.18
3.56 0.18
3.58 0.18
3.50 0.18
2.31 0.12
3.52 0.18
3.61 0.18
3.52 0.18
3.89 0.19
3.98 0.20
3.50 0.18
6.65 0.33
7.45 0.37
6.26 0.31
5.99 0.30
6.42 0.32
8.59 0.43
7.54 0.38
7.10 0.36
6.33 0.32
6.93 0.35
5.82 0.29
5.71 0.29
5.50 0.28
4.32 0.22
5.54 0.28
6.42 0.32
5.92 0.30
5.73 0.29
5.62 0.28
5.62 0.28
2.50 0.13
2.55 0.13
2.50 0.13
1.72 0.09
2.40 0.12
2.51 0.13
2.52 0.13
2.50 0.13
1.82 0.09
2.34 0.12
2.51 0.13
2.51 0.13
2.51 0.13
1.56 0.08
1.61 0.08
3.52 0.18
3.55 0.18
2.43 0.12
2.48 0.12
2.52 0.13

S. Schwarz, R. Csuk / Bioorg. Med. Chem. 18 (2010) 7458–7474
7461
Table 5
Comparison of L- and D-alanyl substituted derivatives (cytotoxicity, IC50 values in
l
M using 15 human tumour cell lines (error: 5%)
12 ( -form) 24 ( -form)
Derivative/cell line
9 (
L-form)
23 (D
-form)
L
D
15 (
L
-form)
25 (D-form)
518A2
8505C
A253
A2780
A431
A549
DLD-1
FaDu
HCT-116
HCT-8
HT-29
Lipo
MCF-7
SW1736
SW480
Average
3.54 0.18
4.31 0.22
3.61 0.18
2.98 0.15
3.48 0.17
2.77 0.14
4.49 0.22
4.52 0.23
2.74 0.14
2.80 0.14
2.87 0.14
4.30 0.22
3.54 0.18
3.22 0.16
3.52 0.18
3.51 0.18
2.26 0.11
2.92 0.15
2.26 0.11
2.24 0.11
2.36 0.12
2.26 0.11
3.35 0.17
2.25 0.11
2.25 0.11
2.26 0.11
2.80 0.14
3.56 0.18
2.25 0.11
2.25 0.11
3.52 0.18
2.59 0.13
2.72 0.14
3.87 0.19
2.33 0.12
2.59 0.13
2.27 0.11
3.43 0.17
3.72 0.19
4.25 0.21
2.82 0.14
2.21 0.11
2.50 0.13
2.74 0.14
3.55 0.18
2.92 0.15
2.79 0.14
2.98 0.15
2.76 0.14
4.43 0.22
2.55 0.13
3.26 0.16
2.76 0.14
4.35 0.22
4.49 0.22
3.90 0.20
4.25 0.21
2.42 0.12
4.38 0.22
4.13 0.21
3.55 0.18
4.11 0.21
3.32 0.17
3.64 0.18
5.09 0.25
3.49 0.17
3.51 0.18
2.08 0.10
3.49 0.17
3.43 0.17
5.54 0.28
5.39 0.27
5.03 0.25
5.13 0.26
4.60 0.23
3.53 0.18
3.52 0.18
3.54 0.18
3.50 0.18
4.06 0.20
5.48 0.27
3.51 0.18
3.50 0.18
1.70 0.09
3.11 0.16
3.17 0.16
5.67 0.28
5.48 0.27
4.82 0.24
3.32 0.17
3.47 0.17
4.73 0.24
3.52 0.18
3.46 0.17
3.47 0.17
3.89 0.19
Figure 5. Results from the AO/EB test; treatment of A549 cells with (from left to right): GA (90 lM), 8 (8 lM), 9 (3.5 lM), 10 (3 lM) and 25 (3 lM).
apoptotic processes. In summary, nearly of the GA derivatives
showed a higher activity than GA and a better selectivity towards
tumour cells.
4. Experimental
4.1. Biology
4.1.1. Cell lines and culture conditions
The cell lines 518A2, 8505C, A253, A2780, A431, A549, DLD-1,
FaDu, HCT-116, HCT-8, HT-29, LIPO, MCF-7, NiH3T3, SW1736 and
SW480 were included in this study. Cultures were maintained as
monolayer in RPMI 1640 (PAA Laboratories, Pasching, Germany)
supplemented with 10% heat inactivated foetal bovine serum
(Biochrom AG, Berlin, Germany) and penicillin/streptomycin (PAA
Laboratories) at 37 °C in a humidified atmosphere of 5% CO2/95%
air.
4.1.2. Cytotoxicity assay21
The cytotoxicity of the compounds was evaluated using the
sulforhodamine B (SRB) (Sigma–Aldrich) microculture colorimetric
assay. In short, exponentially growing cells were seeded into
96-well plates on day 0 at the appropriate cell densities to prevent
confluence of the cells during the period of experiment. After 24 h,
the cells were treated with serial dilutions of the compounds
(0–100 lM) for 96 h. The final concentration of DMSO or DMF sol-
vent never exceeded 0.5%, which was non-toxic to the cells. The
percentages of surviving cells relative to untreated controls were
determined 96 h after the beginning of drug exposure. After a
96 h treatment, the supernatant medium from the 96-well plates
was thrown away and the cells were fixed with 10% TCA. For a
thorough fixation, the plates were allowed to rest at 4 °C. After
fixation, the cells were washed in a strip washer. The washing
was done five times with water using alternate dispensing and
aspiration procedures. Afterwards the plates were dyed with
Figure 6. DNA laddering for the ovarian cancer cell line A2780 after treatment with
IC90-concentrations for 24 h; left trace: GA; right trace: compound 10.
18–20
2-cyano-3,11-dioxo derivative
showed a cytotoxicity being
comparable to the bioactivity observed for our compounds.
As demonstrated by fluorescence microscopy and DNA ladder-
ing experiments, the cytotoxicity of the compounds results from

7462
S. Schwarz, R. Csuk / Bioorg. Med. Chem. 18 (2010) 7458–7474
100
l
l of 0.4% SRB (sulforhodamine B) for about 20 min. The plates
with water and brine, dried over sodium sulfate, filtered and the
solvent was evaporated. Purification was performed by flash chro-
matography (SiO2, hexane/ethyl acetate 8:2).
were washed with 1% acetic acid to remove the excess of the dye
and allowed to air dry overnight. 100 l of 10 mM Tris base solu-
l
tion were added to each well and absorbance was measured at
570 nm (using a 96-well plate reader, Tecan Spectra, Crailsheim,
Germany). The IC50 was estimated by linear regression between
the value before and after the 50% line is crossed in a dose–
response curve.
4.2.4. General procedure for deprotection (method B)
To a solution of the Boc-protected compound in dry DCM, triflu-
oroacetic acid (1 ml per 10 ml DCM) was added. The mixture was
allowed to stir at room temperature for 12 h. After completion of
the reaction (as monitored by TLC) the solution was washed with
a satd aq sodium hydrogen carbonate. The aqueous layer was ex-
tracted with DCM, the combined organic extracts were washed
with brine, dried over sodium sulfate, filtrated and evaporated to
yield the amine.
4.1.3. Apoptosis test—acridine orange/ethidium bromide
(AO/EB)22
Apoptotic cell death was analysed by acridine orange/ethidium
bromide dye using fluorescence microscopy on A549 cells. There-
fore approx. 500,000 cells were seeded in cell culture flasks and
were allowed to grow for 24 h. The medium was removed and
the substance loaded medium was added. After 24–48 h, the
supernatant medium was collected and centrifuged; the pellet
was suspended in phosphate-buffer saline (PBS) and centrifuged
again. The liquid was removed, the pellet was suspended in PBS.
After mixing the suspension with a solution of AO/EB, analysis
was performed under a fluorescence microscope. While a green
fluorescence shows apoptosis, a red coloured nucleus indicates ne-
crotic cells.
4.2.5. General procedure for deprotection (method C)25
The solution of the benzyl ester (1 equiv) in a mixture of MeOH
and THF (1:2) was purged with argon for 3 min, followed by the
addition of ammonium formate (5 equiv). Palladium on activated
coal (10%; 100 mg per mmol) was added and the mixture was stir-
red at room temperature for 12–14 h. The solvents were removed
under reduced pressure and the residue was dissolved in DCM.
Usual aqueous work-up followed by chromatography (SiO2, hex-
ane/ethyl acetate 1:1) yielded the product.
4.1.4. Apoptosis test—DNA laddering
The DNA fragmentation assay was performed as described23
previously.
4.2.6. General procedure for deprotection (method D)
The Boc-protected compound was dissolved in dry DCM. After
saturation with dry hydrogen chloride gas for 15 min stirring at
room temperature was continued for 12 h. After completion of
the reaction (as monitored by TLC), the solvent was removed under
reduced pressure. The residue was washed with ethyl acetate until
no parent substance could be detected; analytical samples were
obtained by re-crystallization.
4.2. Chemistry
4.2.1. General
Used reagents were bought from commercial suppliers without
any further purification. NMR spectra were measured on VARIAN
Gemini 200, Gemini 2000 or Unity 500 spectrometers at 27 °C with
trimethylsilane as an internal standard, d are given in ppm and J in
Hertz. Mass spectra were taken on a FINNIGAN MAT TSQ 7000
(electronspray, voltage 4.5 kV, sheath gas nitrogen) instrument.
IR spectra are recorded on a Perkin–Elmer FT-IR spectrometer
Spectrum 1000, optical rotations on a Perkin–Elmer 341 polarime-
ter (1 cm micro cell) and UV–vis spectra on a Perkin–Elmer unit,
Lambda 14. Melting points were measured with a LEICA hot stage
microscope and are uncorrected. Elemental analysis was done on a
Foss-Heraeus Vario EL unit. TLC was performed on silica gel (Merck
5554, detection by UV absorption). Solvents were dried before use
according to usual procedures.
4.2.6.1. Methyl 3b-hydroxy-11-oxo-olean-12-en-30-oate (1). To
a solution of GA (31.00 g, 65.9 mmol) in dry DMF (150 ml) potas-
sium carbonate (15.34 g, 111.0 mmol) was added. After 30 min of
stirring at room temperatures, iodomethane (4.94 ml, 79.0 mmol)
was added and the mixture was stirred for an additional 2 h. The
solvents were evaporated and the crude residue was dissolved in
a mixture of DCM (300 ml) and hydrochloric acid (50 ml, 1.0 M).
The aqueous layer was extracted with DCM (3 ꢁ 50 ml), the com-
bined organic layers were washed with brine (50 ml), dried
(Na2SO4), filtered and the solvent was evaporated. Recrystallization
from MeOH yielded 1 (29.09 g, 91.1%) as a colourless solid; mp
254–258 °C (lit. 254–258 °C,26 254 °C27); Rf = 0.48 (hexane/ethyl
acetate 7:3); ½a D20
ꢂ
= 141.18 (c 0.48, CHCl3); UV–vis (MeOH): kmax
(log e
) = 270 nm (4.15); MS (ESI): m/z (%) = 485.5 ([M+H]+, 55),
4.2.2. General procedure for the protection of the amino acids24
The amino acid (1 equiv) was dissolved in 1:1mixture of a
potassium hydroxide solution (2 M in water) and 1,4-dioxane. Di
tert-butyl dicarbonate (1.2 equiv) was added and the mixture al-
lowed to stir at room temperature for 12 h. The solvent was re-
moved under reduced pressure and ethyl acetate was added.
After washing with aq sodium hydrogensulfate (10% in water),
the mixture was extracted 3ꢁ with ethyl acetate. The combined or-
ganic layers were washed with brine, dried over sodium sulfate, fil-
tered and the solvent was evaporated. The crude protected amino
acid was used without any further purification; for biological test-
ing an analytic sample was obtained by chromatography.
507.5 ([M+Na]+, 12), 539.1 ([M+Na+MeOH]+, 100); IR (KBr):
= 3614 (br), 2970 (s), 2955 (s), 2875 (m), 1726 (s), 1659 (s),
1466 (m), 1450 (m), 1364 (w), 1216 (m), 1189 (m), 1136 (w),
1085 (w), 1040 (w), 992 (w) cmꢃ1 1H NMR (400 MHz, CDCl3):
m
;
d = 5.65 (s, 1H, H-12), 3.67 (s, 3H, COOCH3), 3.21 (dd, 1H, H-3,
J = 10.8, 5.7 Hz), 2.78 (ddd, 1H, H-1, J = 13.3, 3.3, 3.37 Hz), 2.32
(s, 1H, H-9), 2.06 (dd, 1H, H-18, J = 13.3, 3.87 Hz), 2.00 (m, 1H,
H-15), 1.95 (m, 1H, H-21), 1.90 (dd, 1H, H-19, J = 13.8, 3.97 Hz),
1.83 (ddd, 1H, H-16, J = 14.3, 14.3, 5.27 Hz), 1.65 (m, 1H, H-2),
1.62 (m, 1H, H-7), 1.58 (m, 1H, H-20), 1.57 (m, 1H, H-190), 1.57
(m, 1H, H-6), 1.43 (m, 1H, H-60), 1.38 (m, 1H, H-70), 1.36 (m, 1H,
H-22), 1.34 (s, 3H, H-27), 1.30 (m, 1H, H-220), 1.28 (m, 1H,
H-210), 1.17 (m, 1H, H-160), 1.13 (s, 3H, H-28), 1.12 (s, 3H, H-25),
1.11 (s, 3H, H-26), 1.00 (m, 1H, H-150), 0.99 (s, 3H, H-23), 0.96
(m, 1H, H-10), 0.79 (s, 3H, H-24), 0.79 (s, 3H, H-29), 0.68 (m, 1H,
H-5); 13C NMR (125 MHz, CDCl3): d = 200.0 (C-11), 176.8 (C-30),
169.0 (C-13), 128.6 (C-12), 78.8 (C-3), 61.9 (C-9), 55.1 (C-5), 51.8
(COOCH3), 48.5 (C-18), 45.5 (C-8), 44.1 (C-20), 43.3 (C-14), 41.2
4.2.3. General procedure for esterifications in position C(3)
(method A)
The starting material (1 equiv) was dissolved in dry DCM, DMAP
(20 mg, 0.16 mmol) and the protected amino acid (1.2 equiv) were
added. After addition of DCC (1.2 equiv) the mixture was stirred at
room temperature for 12 h, filtered and the filtrate was washed

S. Schwarz, R. Csuk / Bioorg. Med. Chem. 18 (2010) 7458–7474
7463
(C-19), 39.2 (C-1), 39.2 (C-4), 37.8 (C-22), 37.2 (C-10), 32.9 (C-7),
31.9 (C-17), 31.2 (C-21), 28.6 (C-29), 28.4 (C-23), 28.2 (C-28),
27.4 (C-2), 26.6 (C-16), 26.6 (C-15), 23.5 (C-27), 18.8 (C-26), 17.6
(C-6), 16.4 (C-25), 15.6 (C-24).
(C-20), 43.2 (C-14), 41.1 (C-19), 39.1 (C-1), 39.1 (C-4), 37.7 (C-22),
37.1 (C-10), 32.8 (C-7), 31.8 (C-17), 31.1 (C-21), 28.6 (C-29), 28.2
(C-23), 28.1 (C-28), 27.3 (C-2), 26.5 (C-16), 26.4 (C-15), 23.4 (C-27),
21.9 (i-Pr-CH3), 21.7 (i-Pr-CH3), 18.7 (C-26), 17.5 (C-6), 16.3 (C-25),
15.6 (C-24).
4.2.6.2. Ethyl 3b-hydroxy-11-oxo-olean-12-en-30-oate (2). Fol-
lowing the procedure given for 1, compound 2 was obtained from
GA and iodoethane as a white solid (1.75 g, 82%); mp 220–224 °C
4.2.6.4.
Benzyl
3b-hydroxy-11-oxo-olean-12-en-30-oate
(4). Compound 4 was obtained from GA and benzyl bromide as
a white solid (8.61 g, 73%); mp 134–137 °C (lit. 125–126 °C,7
129–30 °C,28 131–133 °C29); Rf = 0.45 (hexane/ethyl acetate 7:3);
(lit. 93–94 °C7); Rf = 0.40 (hexane/ethyl acetate 7:3);
½
a 2D0
=
ꢂ
144.35 (c 0.48, CHCl3); UV–vis (MeOH): kmax (log
(3.90); MS (ESI): m/z (%) = 499.5 ([M+H]+, 90), 521.4 ([M+Na]+,
13), 552.9 ([M+Na+MeOH]+, 100); IR (KBr):
= 3543 (br), 2939
e) = 267 nm
½
a 2D0
ꢂ
= 136.41 (c 0.25, CHCl3); UV–vis (MeOH): kmax (log
e) =
m
207 nm (4.08), 249 nm (4.12); MS (ESI): m/z (%) = 561.5 ([M+H]+,
(s), 2869 (m), 1726 (s), 1651 (s), 1616 (m), 1455 (m), 1389 (m),
1364 (w), 1330 (m), 1312 (w), 1278 (w), 1257 (m), 1210 (m),
1172 (s), 1135 (w), 1086 (m), 1042 (m), 1028 (m), 994 (m), 920
56), 583.4 ([M+Na]+, 26), 863.9 ([3M+2Na]2+
([2M+H]+, 54), 1143.3 ([2M+Na]+, 100); IR (KBr):
,
10), 1121.2
= 3432 (br),
m
2932 (s), 2870 (m), 1725 (s), 1654 (s), 1616 (w), 1467 (m), 1455
(m), 1387 (m), 1356 (w), 1323 (w), 1280 (w), 1257 (w), 1215
(m), 1188 (m), 1150 (s), 1084 (m), 1038 (m), 995 (m), 954 (w),
917 (w), 880 (w), 821 (w), 754 (w), 699 (m), 674 (w), 607 (w),
(w), 880 (w), 767 (w), 704 (w), 671 (w), 604 (w) cmꢃ1 1H NMR
;
(400 MHz, CDCl3): d = 5.61 (s, 1H, H-12), 4.16 (dq, 1H, methy-
lene-HH0, J = 10.8, 7.17 Hz), 4.10 (dq, 1H, methylene-HH0, J = 10.8,
7.17 Hz), 3.19 (dd, 1H, H-3, J = 11.1, 5.17 Hz), 2.76 (ddd, 1H, H-1,
J = 13.5, 3.6, 3.67 Hz), 2.31 (s, 1H, H-9), 2.07 (ddd, 1H, H-18,
J = 12.5, 4.1, 1.17 Hz), 2.00 (ddd, 1H, H-15, J = 13.7, 13.7, 4.57 Hz),
1.96 (m, 1H, H-21), 1.88 (ddd, 1H, H-19, J = 13.5, 4.2, 2.87 Hz),
1.80 (ddd, 1H, H-16, J = 13.7, 13.7, 4.37 Hz), 1.64 (m, 1H, H-2),
1.61 (m, 1H, H-7), 1.58 (m, 1H, H-20), 1.57 (m, 1H, H-190), 1.56
(m, 1H, H-6), 1.42 (ddd, 1H, H-60, J = 12.4, 3.1, 3.17 Hz), 1.38 (m,
1H, H-70), 1.35 (m, 1H, H-22), 1.34 (s, 3H, H-27), 1.28 (m, 1H,
H-220), 1.26 (m, 1H, H-210), 1.23 (t, 3H, ethyl, J = 7.17 Hz), 1.15
(m, 1H, H-160, J = 13.7, 4.5, 2.77 Hz), 1.11 (s, 3H, H-28), 1.11 (s,
3H, H-25), 1.10 (s, 3H, H-26), 0.99 (m, 1H, H-150), 0.97 (s, 3H,
H-23), 0.95 (ddd, 1H, H-10, J = 10.4, 4.4, 4.47 Hz), 0.78 (s, 3H, H-
24), 0.78 (s, 3H, H-29), 0.67 (dd, 1H, H-5, J = 11.5, 1.67 Hz); 13C
NMR (125 MHz, CDCl3): d = 200.2 (C-11), 176.3 (C-30), 169.2
(C-13), 128.5 (C-12), 78.7 (C-3), 61.8 (C-9), 60.3 (ethylene), 54.9
(C-5), 48.4 (C-18), 45.4 (C-8), 43.8 (C-20), 43.2 (C-14), 41.1
(C-19), 39.1 (C-1), 39.1 (C-4), 37.7 (C-22), 37.1 (C-10), 32.7 (C-7),
31.8 (C-17), 31.1 (C-21), 28.5 (C-29), 28.3 (C-23), 28.1 (C-28),
27.3 (C-2), 26.5 (C-16), 26.4 (C-15), 23.4 (C-27), 18.7 (C-26), 17.5
(C-6), 16.3 (C-25), 15.5 (C-24), 14.3 (methyl).
543 (w) cmꢃ1 1H NMR (400 MHz, CDCl3): d = 7.39–7.25 (m, 5H,
;
H-Ar), 5.53 (s, 1H, H-12), 5.18 (d, 1H, Bn-CHH0, J = 12.37 Hz), 5.07
(d, 1H, Bn-CHH0, J = 12.47 Hz), 3.20 (dd, 1H, H-3, J = 11.1,
5.47 Hz), 2.77 (ddd, 1H, H-1, J = 13.2, 3.7, 3.77 Hz), 2.30 (s, 1H,
H-9), 2.02 (m, 1H, H-18), 2.00 (m, 1H, H-15), 1.95 (m, 1H, H-21),
1.91 (dd, 1H, H-19, J = 13.5, 3.9, 2.67 Hz), 1.79 (ddd, 1H, H-16,
J = 13.4, 13.4, 4.57 Hz), 1.66 (m, 1H, H-2), 1.62 (m, 1H, H-7), 1.60
(m, 1H, H-20), 1.59 (dd, 1H, H-190, J = 13.1, 13.17 Hz), 1.57 (m, 1H,
H-6), 1.45 (m, 1H, H-60), 1.40 (m, 1H, H-70), 1.34 (m, 1H, H-22),
1.33 (s, 3H, H-27), 1.29 (m, 1H, H-210), 1.28 (m, 1H, H-220), 1.15
(m, 1H, H-160), 1.14 (s, 3H, H-28), 1.12 (s, 3H, H-25), 1.09 (s, 3H,
H-26), 0.99 (m, 1H, H-150), 0.98 (s, 3H, H-23), 0.97 (m, 1H, H-10),
0.78 (s, 3H, H-24), 0.71 (s, 3H, H-29), 0.67 (m, 1H, H-5); 13C NMR
(125 MHz, CDCl3): d = 200.1 (C-11), 176.2 (C-30), 168.9 (C-13),
136.1 (Car), 128.6 (Car), 128.6 (Car), 128.4 (C-12), 128.3 (Car),
128.2 (Car), 128.2 (Car), 78.7 (C-3), 66.2 (Bn-CH2), 61.8 (C-9), 54.9
(C-5), 48.2 (C-18), 45.3 (C-8), 44.0 (C-20), 43.1 (C-14), 41.1
(C-19), 39.1 (C-1), 39.1 (C-4), 37.6 (C-22), 37.1 (C-10), 32.7 (C-7),
31.7 (C-17), 31.1 (C-21), 28.4 (C-29), 28.3 (C-23), 28.1 (C-28),
27.3 (C-2), 26.4 (C-16), 26.4 (C-15), 23.3 (C-27), 18.7 (C-26), 17.5
(C-6), 16.3 (C-25), 15.5 (C-24).
4.2.6.3. i-Propyl 3b-hydroxy-11-oxo-olean-12-en-30-oate (3). Com-
pound 3 was obtained from GA and i-propyl iodide as a white solid
(3.48 g, 59%); mp 209–213 °C (lit. 238 °C (dec)7); Rf = 0.50 (hexane/
4.2.6.5. 3b-(Glycyl)-11-oxo-olean-12-en-30-oic acid hydrochlo-
ride (5). Obtained from 26 by method D as a colourless powder;
yield: 210 mg, 63%; mp 300–302 °C (decomp.); Rf = 0.69 (MeOH);
ethyl acetate 7:3); ½a D20
ꢂ
= 145.82 (c 0.37, CHCl3); UV–vis (MeOH):
kmax (log
e
) = 250 nm (4.09); MS (ESI): m/z (%) = 513.5 ([M+H]+, 68),
½
a 2D0
ꢂ
= 82.99 (c 0.50, MeOH); UV–vis (MeOH): kmax (log
e
) = 249 nm
567.0 ([M+MeOH+Na]+, 92), 1025.3 ([2M+H]+, 80), 1047.3
([2M+Na]+, 100); IR (KBr):
= 3521 (br), 2980 (s), 2946 (s), 2856
(3.93); MS (ESI): m/z (%) = 528.2 ([M+H]+, 100); IR (KBr):
m
= 3420
m
(br), 2951 (s), 1746 (s), 1656 (s), 1466 (s), 1389 (s), 1324 (m),
(s), 1720 (s), 1642 (s), 1612 (m), 1457 (s), 1388 (s), 1327 (m), 1309
(m), 1278 (m), 1255 (m), 1210 (s), 1174 (s), 1135 (m), 1106 (s),
1084 (m), 1047 (m), 1028 (m), 996 (m), 981 (m), 948 (w), 917 (m),
878 (w), 848 (s), 769 (w), 715 (w), 702 (w), 688 (w), 673 (w), 636
1245 (s), 1086 (s), 987 (m), 909 (m), 819 (w), 749 (w), 670 (w),
589 (w), 542 (w), 462 (w) cmꢃ1 1H NMR (400 MHz, MeOH-d4):
;
d = 5.59 (s, 1H, H-12), 4.68 (dd, 1H, H-3, J = 12.0, 4.67 Hz), 3.84
(dd, 2H, Gly-CH2, J = 23.3, 17.17 Hz), 2.79 (ddd, 1H, H-1, J = 13.7,
3.6, 3.67 Hz), 2.50 (s, 1H, H-9), 2.20 (m, 1H, H-18), 2.15 (ddd, 1H,
H-15, J = 13.3, 13.3, 4.67 Hz), 1.95 (m, 1H, H-21), 1.88 (m, 1H,
H-16), 1.84 (m, 1H, H-19), 1.79 (m, 1H, H-2), 1.75 (m, 1H, H-7),
1.71 (dd, 1H, H-190, J = 13.4, 13.47 Hz), 1.67 (m, 1H, H-20), 1.64
(m, 1H, H-6), 1.53 (m, 1H, H-60), 1.49 (m, 1H, H-70), 1.47 (m, 1H,
H-22), 1.43 (s, 3H, H-27), 1.39 (m, 1H, H-210), 1.25 (m, 1H,
H-220), 1.23 (m, 1H, H-160), 1.17 (s, 3H, H-25), 1.16 (s, 3H, H-28),
1.15 (s, 3H, H-28), 1.12 (m, 1H, H-10), 1.04 (m, 1H, H-150), 0.94 (s,
3H, H-23), 0.93 (s, 3H, H-24), 0.91 (m, 1H, H-5), 0.83 (s, 3H,
H-29); 13C NMR (125 MHz, MeOH-d4): d = 200.9 (C-11), 178.9
(C-30), 171.6 (Gly-COO), 167.0 (C-13), 127.4 (C-12), 83.2 (C-3),
61.4 (C-9), 54.6 (C-5), 48.5 (C-18), 45.3 (C-8), 43.2 (C-20), 41.0
(C-14), 39.7 (C-19), 38.2 (Gly-CH2), 37.7 (C-1 and C-4), 37.6
(C-22), 36.8 (C-10), 32.2 (C-7), 31.5 (C-17), 30.6 (C-21), 27.8
(C-29), 27.3 (C-23), 27.0 (C-28), 26.2 (C-16), 25.9 (C-15), 23.0
(C-2), 22.4 (C-27), 17.8 (C-26), 17.0 (C-6), 15.6 (C-24), 15.5
(w), 591 (w), 541 (w), 475 (w), 424 (w) cmꢃ1 1H NMR (400 MHz,
;
CDCl3): d = 5.60 (s, 1H, H-12), 5.00 (qq, 1H, i-Pr-CH, J = 6.2,
6.27 Hz), 3.20 (dd, 1H, H-3, J = 10.9, 5.57 Hz), 2.76 (ddd, 1H, H-1,
J = 13.3, 3.6, 3.6), 2.32 (s, 1H, H-9), 2.07 (dd, 1H, H-18, J = 13.4,
3.47 Hz), 2.02 (ddd, 1H, H-15, J = 13.7, 13.7, 4.67 Hz), 1.97 (m, 1H,
H-21), 1.87 (m, 1H, H-19), 1.80 (ddd, 1H, H-16, J = 13.6, 13.6,
4.57 Hz), 1.67 (m, 1H, H-2), 1.64 (m, 1H, H-7), 1.62 (m, 1H, H-20),
1.58 (dd, 1H, H-190, J = 13.1, 13.17 Hz), 1.57 (m, 1H, H-6), 1.45 (m,
1H, H-60), 1.40 (m, 1H, H-70), 1.34 (m, 1H, H-22), 1.34 (s, 3H, H-27),
1.28 (m, 1H, H-210), 1.27 (m, 1H, H-220), 1.23 (d, 3H, i-Pr-CH3,
J = 6.27 Hz), 1.20 (d, 3H, i-Pr-CH3, J = 6.27 Hz), 1.16 (m, 1H, H-160),
1.11 (s, 3H, H-28), 1.10 (s, 6H, H-25 and H-26), 0.99 (m, 1H, H-150),
0.98 (s, 3H, H-23), 0.95 (m, 1H, H-10), 0.78 (s, 3H, H-24), 0.77 (s, 3H,
H-29), 0.67 (m, 1H, H-5); 13C NMR (125 MHz, CDCl3): d = 200.2
(C-11), 175.8 (C-30), 169.4 (C-13), 128.5 (C-12), 78.8 (C-3), 67.4
(i-Pr-CH), 61.8 (C-9), 54.9 (C-5), 48.4 (C-18), 45.4 (C-8), 43.7

7464
S. Schwarz, R. Csuk / Bioorg. Med. Chem. 18 (2010) 7458–7474
(C-25). Anal. Calcd for C32H50ClNO5 (564.20): C, 68.12; H, 8.93; Cl,
6.28; N, 2.48. Found: C, 68.01; H, 9.17; Cl, 6.13; N, 2.41.
4.2.6.8.
Methyl
3b-(glycyl)-11-oxo-olean-12-en-30-oate
(8). Obtained from 29 by method B as a colourless powder; yield:
200 mg, 79%; mp 280–282 °C; Rf = 0.57 (DCM/MeOH 9:1);
4.2.6.6. 3b-(
L
-Alanyl)-11-oxo-olean-12-en-30-oic acid hydro-
½
a 2D0
ꢂ
= 123.02 (c 0.43, CHCl3); UV–vis (MeOH): kmax (log
249 nm (4.08); MS (ESI): m/z (%) = 542.2 ([2M+2H]2+, 10); IR
(KBr): = 3382 (br), 2966 (s), 2873 (m), 2856 (m), 2362 (w),
e) =
chloride (6). Obtained from 27 by method D as a colourless pow-
der; yield: 50 mg, 51%; mp 309–311 °C (decomp.); Rf = 0.75
m
(MeOH); ½a 2D0
ꢂ
= 103.68 (c 0.58, MeOH); UV–vis (MeOH): kmax
1743 (s), 1728 (s), 1651 (s), 1467 (m), 1454 (m), 1390 (m), 1361
(w), 1320 (w), 1278 (w), 1248 (w), 1217 (s), 1190 (m), 1155 (m),
1086 (m), 1049 (w), 1023 (w), 984 (w), 971 (m), 921 (m), 880
(w), 869 (s), 770 (w), 748 (w), 702 (w), 668 (w), 591 (w), 543 (w)
(log e
) = 249 nm (4.01); MS (ESI): m/z (%) = 542.1 ([M+H]+, 100);
IR (KBr):
m = 3421 (br), 2962 (s), 2642 (m), 2585 (m), 2512 (w),
2012 (w), 1737 (s), 1707 (s), 1651 (s), 1604 (s), 1518 (m), 1456
(s), 1388 (s), 1364 (m), 1326 (m), 1290 (s), 1262 (s), 1213 (s),
1163 (s), 1111 (s), 1049 (m), 1021 (m), 984 (m), 958 (m), 913
(m), 885 (w), 869 (w), 804 (w), 771 (w), 748 (w), 700 (w), 683
cmꢃ1 1H NMR (400 MHz, CDCl3): d = 5.63 (s, 1H, H-12), 4.55 (dd,
;
1H, H-3, J = 11.6, 4.67 Hz), 3.66 (s, 3H, OMe), 3.41 (s, 2H, Gly-
CH2), 2.79 (ddd, 1H, H-1, J = 13.7, 3.6, 3.67 Hz), 2.33 (s, 1H, H-9),
2.05 (m, 1H, H-18), 2.00 (m, 1H, H-15), 1.96 (m, 1H, H-21), 1.89
(ddd, 1H, H-19, J = 13.3, 3.7, 2.57 Hz), 1.79 (ddd, 1H, H-16,
J = 14.2, 14.2, 4.67 Hz), 1.69 (m, 1H, H-2), 1.64 (m, 1H, H-7), 1.61
(m, 1H, H-20), 1.58 (dd, 1H, H-190, J = 13.4, 13.47 Hz), 1.56 (m, 1H,
H-6), 1.45 (m, 1H, H-60), 1.40 (m, 1H, H-70), 1.37 (m, 1H, H-22),
1.33 (s, 3H, H-27), 1.32 (m, 1H, H-220), 1.28 (m, 1H, H-210), 1.15
(m, 1H, H-160), 1.13 (s, 3H, H-25), 1.12 (s, 3H, H-26), 1.09 (s, 3H,
H-28), 1.03 (ddd, 1H, H-10, J = 13.3, 13.3, 3.87 Hz), 0.98 (m, 1H,
H-150), 0.85 (s, 6H, H-23 and H-24), 0.78 (m, 1H, H-5), 0.77
(s, 3H, H-29); 13C NMR (125 MHz, CDCl3): d = 200.0 (C-11), 176.9
(C-30), 173.9 (Gly-COO), 169.2 (C-13), 128.5 (C-12), 81.4 (C-3),
61.7 (C-9), 55.0 (C-5), 51.7 (OMe), 48.4 (C-18), 45.4 (C-8), 44.0
(C-20), 44.0 (Gly-CH2), 43.2 (C-14), 41.1 (C-19), 38.7 (C-1), 38.1
(C-4), 37.7 (C-22), 36.9 (C-10), 32.7 (C-7), 31.8 (C-17), 31.1
(C-21), 28.5 (C-29), 28.3 (C-23), 28.1 (C-28), 26.4 (C-16), 26.4
(C-15), 23.6 (C-2), 23.3 (C-27), 18.6 (C-26), 17.3 (C-6), 16.7
(C-24), 16.4 (C-25). Anal. Calcd for C33H51NO5 (541.76): C, 73.16;
H, 9.49; N, 2.59. Found: C, 73.02; H, 9.57; N, 2.41.
(w), 672 (w), 589 (w), 542 (w) cmꢃ1 1H NMR (400 MHz, MeOH-
;
d4): d = 5.59 (s, 1H, H-12), 4.67 (dd, 1H, H-3, J = 12.0, 4.57 Hz),
4.09 (q, 1H, Ala-CH, J = 7.27 Hz), 2.79 (ddd, 1H, H-1, J = 13.6, 3.4,
3.47 Hz), 2.50 (s, 1H, H-9), 2.21 (m, 1H, H-18), 2.15 (ddd, 1H,
H-15, J = 13.7, 13.7, 4.37 Hz), 1.94 (m, 1H, H-21), 1.89 (m, 1H,
H-16), 1.84 (m, 1H, H-19), 1.78 (m, 1H, H-2), 1.75 (m, 1H, H-7),
1.71 (dd, 1H, H-190, J = 13.2, 13.27 Hz), 1.67 (m, 1H, H-20), 1.63
(m, 1H, H-6), 1.56 (d, 3H, Ala-CH3, J = 7.37 Hz), 1.53 (m, 1H, H-60),
1.49 (m, 1H, H-70), 1.47 (m, 1H, H-22), 1.43 (s, 3H, H-27), 1.40
(m, 1H, H-210), 1.25 (m, 1H, H-220), 1.24 (m, 1H, H-160), 1.18 (s,
3H, H-25), 1.17 (s, 3H, H-28), 1.15 (s, 3H, H-28), 1.13 (m, 1H,
H-10), 1.05 (m, 1H, H-150), 0.95 (s, 3H, H-23), 0.93 (s, 3H, H-24),
0.92 (m, 1H, H-5), 0.83 (s, 3H, H-29); 13C NMR (125 MHz, MeOH-
d4): d = 200.9 (C-11), 178.9 (C-30), 171.6 (Ala-COO), 169.4 (C-13),
127.4 (C-12), 83.2 (C-3), 61.4 (C-9), 54.5 (C-5), 48.7 (Ala-CH),
48.5 (C-18), 45.3 (C-8), 43.2 (C-20), 41.0 (C-14), 38.2 (C-19), 37.9
(C-1), 37.6 (C-4), 37.6 (C-22), 36.8 (C-10), 32.2 (C-7), 31.5 (C-17),
30.6 (C-21), 27.8 (C-29), 27.3 (C-23), 27.1 (C-28), 26.2 (C-16),
25.9 (C-15), 23.0 (C-2), 22.4 (C-27), 17.8 (C-26), 16.9 (C-6), 15.7
(C-24), 15.5 (C-25), 15.0 (Ala-CH3). Anal. Calcd for C33H52ClNO5
(578.22): C, 68.55; H, 9.06; Cl, 6.13; N, 2.42. Found: C, 68.29; H,
9.21; Cl, 6.24; N, 2.34.
4.2.6.9. Methyl
(9). Obtained from 30 by method B as a colourless powder; yield:
200 mg, 91%; mp 264–267 °C; Rf = 0.59 (DCM/MeOH 9:1);
3b-(L-alanyl)-11-oxo-olean-12-en-30-oate
½
a 2D0
ꢂ
= 137.30 (c 0.35, CHCl3); UV–vis (MeOH): kmax (log
249 nm (4.07); MS (ESI): m/z (%) = 556.1 ([M+H]+, 100); IR (KBr):
= 3442 (br), 2958 (s), 2874 (m), 1731 (s), 1652 (s), 1616 (m),
e) =
4.2.6.7. 3b-(b-Alanyl)-11-oxo-olean-12-en-30-oic acid hydro-
chloride (7). Obtained from 28 by method D as a colourless pow-
der; yield: 100 mg, 39%; mp 305–309 °C (decomp.); Rf = 0.48
m
1457 (m), 1389 (m), 1362 (w), 1318 (m), 1278 (w), 1248 (m),
1217 (s), 1191 (s), 1154 (s), 1087 (m), 1064 (w), 1050 (w), 1022
(w), 986 (m), 973 (w), 984 (w), 918 (w), 880 (w), 868 (w), 825
(MeOH); ½a 2D0
ꢂ
= 117.25 (c 0.51, MeOH); UV–vis (MeOH): kmax
(log e
) = 250 nm (4.08); MS (ESI): m/z (%) = 542.3 ([M+H]+, 100);
IR (KBr):
m
= 3355 (br), 3258 (m), 2957 (s), 2363 (w), 1724 (s),
(w), 770 (w), 685 (w), 671 (w), 590 (w), 544 (w) cmꢃ1 1H NMR
;
1652 (s), 1582 (m), 1527 (m), 1466 (s), 1389 (s), 1365 (s), 1325
(m), 1306 (m), 1278 (m), 1233 (s), 1165 (s), 1105 (s), 1061 (w),
1022 (m), 983 (s), 918 (w), 883 (w), 850 (w), 750 (w), 700 (w),
(400 MHz, CDCl3): d = 5.64 (s, 1H, H-12), 4.54 (dd, 1H, H-3,
J = 11.9, 4.67 Hz), 3.66 (s, 3H, OMe), 3.55 (q, 1H, Ala-CH,
J = 7.27 Hz), 2.79 (ddd, 1H, H-1, J = 13.3, 3.6, 3.67 Hz), 2.34 (s, 1H,
H-9), 2.06 (m, 1H, H-18), 2.00 (m, 1H, H-15), 1.97 (m, 1H, H-21),
1.90 (ddd, 1H, H-19, J = 13.8, 4.1, 2.67 Hz), 1.80 (ddd, 1H, H-16,
J = 13.9, 13.9, 4.77 Hz), 1.70 (m, 1H, H-2), 1.63 (m, 1H, H-7), 1.60
(m, 1H, H-20), 1.59 (dd, 1H, H-190, J = 13.4, 13.47 Hz), 1.56 (m, 1H,
H-6), 1.44 (m, 1H, H-60), 1.39 (m, 1H, H-70), 1.35 (m, 1H, H-22),
1.35 (m, 3H, Ala-CH3), 1.34 (s, 3H, H-27), 1.29 (m, 2H, H-220 and
H-210), 1.16 (m, 1H, H-160), 1.14 (s, 3H, H-25), 1.12 (s, 3H, H-28),
1.10 (s, 3H, H-26), 1.04 (ddd, 1H, H-10, J = 13.8, 13.8, 3.67 Hz), 0.99
(m, 1H, H-150), 0.87 (s, 3H, H-23), 0.85 (s, 3H, H-24), 0.79 (m, 1H,
H-5), 0.78 (s, 3H, H-29); 13C NMR (125 MHz, CDCl3): d = 200.0
(C-11), 176.9 (C-30), 175.9 (Ala-COO), 169.2 (C-13), 128.5 (C-12),
81.2 (C-3), 61.7 (C-9), 55.0 (C-5), 51.8 (OMe), 50.3 (Ala-CH), 48.4
(C-18), 45.4 (C-8), 44.0 (C-20), 43.2 (C-14), 41.1 (C-19), 38.7 (C-1),
38.2 (C-4), 37.7 (C-22), 36.9 (C-10), 32.7 (C-7), 31.8 (C-17), 31.1
(C-21), 28.5 (C-29), 28.3 (C-23), 28.1 (C-28), 26.5 (C-16), 26.4
(C-15), 23.6 (C-2), 23.3 (C-27), 20.6 (Ala-CH3), 18.7 (C-26), 17.3
(C-6), 16.7 (C-24), 16.4 (C-25). Anal. Calcd for C34H53NO5 (555.79):
C, 73.47; H, 9.61; N, 2.52. Found: C, 73.28; H, 9.81; N, 2.34.
683 (w), 669 (w), 589 (w), 541 (w) cmꢃ1 1H NMR (500 MHz,
;
MeOH-d4): d = 5.57 (s, 1H, H-12), 4.57 (dd, 1H, H-3, J = 11.7,
5.07 Hz), 3.18 (t, 2H, Ala-CH2NH2, J = 6.77 Hz), 2.74 (m, 1H, H-1),
2.73 (m, 2H, Ala-CH2COO), 2.47 (s, 1H, H-9), 2.19 (m, 1H, H-18),
2.13 (ddd, 1H, H-15, J = 13.6, 13.6, 4.27 Hz), 1.92 (m, 1H, H-21),
1.87 (m, 1H, H-16), 1.82 (m, 1H, H-19), 1.75 (m, 1H, H-7), 1.72
(m, 1H, H-2), 1.69 (dd, 1H, H-190, J = 13.2, 13.27 Hz), 1.64 (m, 1H,
H-20), 1.60 (m, 1H, H-6), 1.51 (m, 1H, H-60), 1.44 (m, 1H, H-70),
1.41 (s, 3H, H-27), 1.40 (m, 3H, H-22 and H-210 and H-220), 1.23
(m, 1H, H-160), 1.15 (s, 6H, H-25 and H-28), 1.13 (s, 3H, H-26),
1.09 (m, 1H, H-10), 1.03 (m, 1H, H-150), 0.90 (s, 6H, H-23 and H-
24), 0.87 (m, 1H, H-5), 0.82 (s, 3H, H-29); 13C NMR (125 MHz,
MeOH-d4): d = 200.9 (C-11), 179.0 (C-30), 171.6 (Ala-COO), 170.6
(C-13), 127.4 (C-12), 81.7 (C-3), 61.5 (C-9), 54.7 (C-5), 48.5
(C-18), 45.3 (C-8), 43.5 (C-20), 43.2 (C-14), 41.0 (C-19), 38.3
(C-1), 37.7 (C-4), 37.6 (C-22), 36.8 (C-10), 35.0 (Ala-CH2NH2),
32.2 (C-7), 31.5 (C-17), 30.9 (Ala-CH2COO), 30.6 (C-21), 27.8
(C-29), 27.3 (C-28), 27.1 (C-23), 26.2 (C-16), 25.9 (C-15), 23.0
(C-2), 22.4 (C-27), 17.8 (C-26), 17.0 (C-6), 15.7 (C-24), 15.5
(C-25). Anal. Calcd for C33H52ClNO5 (578.22): C, 68.55; H, 9.06;
Cl, 6.13; N, 2.42. Found: C, 68.43; H, 9.22; Cl, 6.24; N, 2.19.
4.2.6.10.
Methyl
3b-(b-alanyl)-11-oxo-olean-12-en-30-oate
(10). Obtained from 31 by method B as a colourless powder;

S. Schwarz, R. Csuk / Bioorg. Med. Chem. 18 (2010) 7458–7474
7465
yield: 370 mg, 95%; mp 267–270 °C; Rf = 0.21 (DCM/MeOH 9:1);
= 121.76 (c 0.48, CHCl3); UV–vis (MeOH): kmax (log ) =
250 nm (4.07); MS (ESI): m/z (%) = 556.2 ([M+H]+, 100); IR (KBr):
= 3380 (br), 2960 (s), 2874 (m), 1726 (s), 1652 (s), 1465 (m),
(C-25), 14.3 (COOCH2CH3). Anal. Calcd for C34H53NO5 (555.79):
C, 73.47; H, 9.61; N, 2.52. Found: C, 73.31; H, 9.84; N, 2.28.
½
a 2D0
ꢂ
e
m
4.2.6.12.
Ethyl
3b-(L-alanyl)-11-oxo-olean-12-en-30-oate
1388 (m), 1368 (m), 1318 (m), 1278 (w), 1250 (m), 1218 (s),
1188 (s), 1160 (s), 1087 (m), 1070 (w), 1023 (w), 986 (m), 948
(w), 918 (w), 880 (w), 853 (w), 824 (w), 770 (w), 721 (w), 685
(12). Obtained from 33 by method B as a colourless powder;
yield: 297 mg, 92%; mp 201–205 °C; Rf = 0.27 (DCM/MeOH 9:1);
½
a 2D0
ꢂ
= 131.56 (c 0.52, CHCl3); UV–vis (MeOH): kmax (log
250 nm (4.09); MS (ESI): m/z (%) = 570.4 ([M+H]+, 100), 855.4
[([3M+2H]]2+, 10), 1139.9 ([2M+H]+, 6); IR (KBr):
= 3425 (br),
e) =
(w), 669 (w), 590 (w), 543 (w) cmꢃ1 1H NMR (500 MHz, CDCl3):
;
d = 5.60 (s, 1H, H-12), 4.49 (dd, 1H, H-3, J = 11.8, 4.77 Hz), 3.62 (s,
3H, OMe), 2.94 (m, 2H, Ala-CH2NH2), 2.74 (ddd, 1H, H-1, J = 13.8,
3.5, 3.57 Hz), 2.42 (t, 2H, Ala-CH2COO, J = 6.37 Hz), 2.30 (s, 1H,
H-9), 2.02 (dd, 1H, H-18, J = 13.8, 3.77 Hz), 1.96 (ddd, 1H, H-15,
J = 13.7, 13.7, 4.57 Hz), 1.92 (m, 1H, H-21), 1.86 (ddd, 1H, H-19,
J = 13.8, 4.2, 3.07 Hz), 1.76 (ddd, 1H, H-16, J = 13.8, 13.8, 4.57 Hz),
1.66 (ddd, 1H, H-2, J = 13.4, 13.4, 3.57 Hz), 1.60 (m, 1H, H-7), 1.56
(m, 1H, H-20), 1.55 (dd, 1H, H-190, J = 13.6, 13.67 Hz), 1.52 (m, 1H,
H-6), 1.40 (ddd, 1H, H-60, J = 12.8, 12.8, 3.27 Hz), 1.35 (m, 1H,
H-70), 1.31 (m, 1H, H-22), 1.30 (s, 3H, H-27), 1.25 (m, 2H, H-220
and H-210), 1.11 (m, 1H, H-160), 1.10 (s, 3H, H-25), 1.08 (s, 3H, H-
28), 1.06 (s, 3H, H-26), 0.99 (ddd, 1H, H-10, J = 13.6, 13.6,
3.67 Hz), 0.95 (m, 1H, H-150), 0.82 (s, 6H, H-23 and H-24), 0.75
(m, 1H, H-5), 0.74 (s, 3H, H-29); 13C NMR (125 MHz, CDCl3):
d = 200.0 (C-11), 176.9 (C-30), 172.4 (Ala-COO), 169.2 (C-13),
128.5 (C-12), 80.7 (C-3), 61.7 (C-9), 55.0 (C-5), 51.7 (OMe), 48.4
(C-18), 45.4 (C-8), 44.0 (C-20), 43.2 (C-14), 41.1 (C-19), 38.7
(C-1), 38.0 (C-4 and Ala-CH2COO), 37.9 (Ala-CH2NH2), 37.7
(C-22), 36.9 (C-10), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21), 28.5
(C-29), 28.3 (C-28), 28.1 (C-23), 26.4 (C-16), 26.4 (C-15), 23.6
(C-2), 23.3 (C-27), 18.6 (C-26), 17.4 (C-6), 16.7 (C-24), 16.4
(C-25). Anal. Calcd for C34H53NO5 (555.79): C, 73.47; H, 9.61; N,
2.52. Found: C, 73.32; H, 9.83; N, 2.37.
m
2960 (s), 2874 (m), 1728 (s), 1654 (s), 1617 (w), 1456 (m), 1389
(m), 1324 (w), 1279 (w), 1247 (w), 1217 (s), 1176 (s), 1086 (w),
1075 (w), 1031 (w), 985 (w), 972 (w), 948 (w), 917 (w), 866 (w),
768 (w), 685 (w), 589 (w), 544 (w) cmꢃ1 1H NMR (500 MHz,
;
CDCl3): d = 5.62 (s, 1H, H-12), 4.54 (dd, 1H, H-3, J = 11.6, 4.67 Hz),
4.17 (dq, 1H, COOCHH0, J = 10.8, 7.17 Hz), 4.10 (dq, 1H, COOCHH0,
J = 10.8, 7.17 Hz), 3.52 (q, 1H, Ala-CHNH2, J = 7.17 Hz), 2.80 (ddd,
1H, H-1, J = 13.7, 3.7, 3.77 Hz), 2.35 (s, 1H, H-9), 2.08 (dd, 1H, H-
18, J = 13.7, 3.77 Hz), 2.01 (ddd, 1H, H-15, J = 13.3, 13.3, 4.27 Hz),
1.97 (m, 1H, H-21), 1.90 (ddd, 1H, H-19, J = 13.7, 4.2, 2.97 Hz),
1.81 (ddd, 1H, H-16, J = 13.7, 13.7, 4.67 Hz), 1.70 (m, 1H, H-2),
1.64 (m, 1H, H-7), 1.60 (m, 1H, H-20), 1.59 (dd, 1H, H-190, J = 13.3,
13.37 Hz), 1.57 (m, 1H, H-6), 1.45 (m, 1H, H-60), 1.40 (m, 1H,
H-70), 1.37 (m, 3H, H-27), 1.35 (s, 3H, H-27), 1.34 (d, 3H, Ala-CH3,
J = 7.17 Hz), 1.31 (m, 1H, H-220), 1.29 (m, 1H, H-210), 1.24 (t, 3H,
COOCH2CH3, J = 7.17 Hz), 1.17 (m, 1H, H-160), 1.15 (s, 3H, H-25),
1.12 (s, 3H, H-28), 1.10 (s, 3H, H-26), 1.04 (ddd, 1H, H-10, J = 13.7,
13.7, 3.77 Hz), 1.00 (m, 1H, H-150), 0.88 (s, 3H, H-23), 0.86 (s, 3H,
H-24), 0.80 (m, 1H, H-5), 0.78 (s, 3H, H-29); 13C NMR (125 MHz,
CDCl3): d = 200.0 (C-11), 176.4 (C-30 and Ala-COO), 169.4 (C-13),
128.4 (C-12), 81.1 (C-3), 61.7 (C-9), 60.3 (COOCH2), 55.0 (C-5),
50.3 (Ala-CNH), 48.4 (C-18), 45.4 (C-8), 43.8 (C-20), 43.2 (C-14),
41.1 (C-19), 38.7 (C-1), 38.2 (C-4), 37.7 (C-22), 36.9 (C-10), 32.7
(C-7), 31.8 (C-17), 31.1 (C-21), 28.5 (C-29), 28.3 (C-23), 28.1
(C-28), 26.5 (C-16), 26.4 (C-15), 23.6 (C-2), 23.3 (C-27), 20.8
(Ala-CH3), 18.7 (C-26), 17.4 (C-6), 16.7 (C-24), 16.4 (C-25), 14.3
(COOCH2CH3). Anal. Calcd for C35H55NO5 (569.81): C, 73.77; H,
9.73; N, 2.46. Found: C, 73.51; H, 9.84; N, 2.22.
4.2.6.11.
Ethyl
3b-(glycyl)-11-oxo-olean-12-en-30-oate
(11). Obtained from 32 by method B as a colourless powder;
yield: 145 mg, 97%; mp 204–206 °C; Rf = 0.27 (DCM/MeOH 9:1);
½
a 2D0
ꢂ
= 126.20 (c 0.57, CHCl3); UV–vis (MeOH): kmax (log
249 nm (4.05); MS (ESI): m/z (%) = 556.3 ([2M+2H]2+, 100), 834.3
([3M+2H]2+, 10), 1111.8 ([2M+H]+, 8); IR (KBr):
= 3366 (br),
e) =
m
3216 (w), 2958 (s), 2874 (m), 1742 (s), 1713 (s), 1651 (s), 1616
(w), 1464 (m), 1390 (m), 1377 (w), 1363 (w), 1321 (m), 1278
(w), 1249 (w), 1217 (s), 1175 (s), 1114 (w), 1087 (w), 1032 (w),
986 (m), 970 (m), 948 (w), 919 (w), 901 (w), 879 (w), 770 (w),
4.2.6.13.
Ethyl
3b-(b-alanyl)-11-oxo-olean-12-en-30-oate
(13). Obtained from 34 by method B as a colourless powder;
yield: 127 mg, 93%; mp 181–184 °C; Rf = 0.12 (DCM/MeOH 9:1);
½
a 2D0
ꢂ
= 125.66 (c 0.51, CHCl3); UV–vis (MeOH): kmax (log
250 nm (4.14); MS (ESI): m/z (%) = 570.3 ([2M+2H]2+, 100); IR
(KBr): = 3434 (br), 2958 (s), 2873 (m), 1727 (s), 1653 (s), 1465
e) =
751 (w), 669 (w), 589 (w), 544 (w) cmꢃ1 1H NMR (500 MHz,
;
CDCl3): d = 5.64 (s, 1H, H-12), 4.57 (dd, 1H, H-3, J = 11.8, 4.87 Hz),
4.18 (dq, 1H, COOCHH0, J = 10.8, 7.17 Hz), 4.11 (dq, 1H, COOCHH0,
J = 10.8, 7.17 Hz), 3.41 (s, 2H, Gly-CH2), 2.81 (ddd, 1H, H-1,
J = 13.7, 3.6, 3.67 Hz), 2.36 (s, 1H, H-9), 2.10 (ddd, 1H, H-18,
J = 13.4, 4.0, 0.87 Hz), 2.02 (ddd, 1H, H-15, J = 13.6, 13.6, 4.47 Hz),
1.98 (m, 1H, H-21), 1.92 (ddd, 1H, H-19, J = 13.6, 4.1, 2.87 Hz),
1.82 (ddd, 1H, H-16, J = 13.6, 13.6, 4.57 Hz), 1.71 (m, 1H, H-2),
1.68 (m, 1H, H-7), 1.66 (m, 1H, H-20), 1.60 (dd, 1H, H-190, J = 13.7,
13.77 Hz), 1.57 (m, 1H, H-6), 1.44 (m, 1H, H-60), 1.40 (m, 1H, H-
70), 1.38 (m, 1H, H-22), 1.36 (s, 3H, H-27), 1.32 (m, 1H, H-220),
1.31 (m, 1H, H-210), 1.25 (t, 3H, COOCH2CH3, J = 7.17 Hz), 1.17
(m, 1H, H-160), 1.15 (s, 3H, H-25), 1.13 (s, 3H, H-28), 1.12 (s, 3H,
H-26), 1.06 (ddd, 1H, H-10, J = 13.7, 13.7, 3.67 Hz), 1.01 (m, 1H, H-
150), 0.87 (s, 6H, H-23 and H-24), 0.81 (m, 1H, H-5), 0.79 (s, 3H,
H-29); 13C NMR (125 MHz, CDCl3): d = 200.0 (C-11), 176.3 (C-30),
174.1 (Gly-COO), 169.4 (C-13), 128.4 (C-12), 81.3 (C-3), 61.7
(C-9), 60.3 (COOCH2), 55.0 (C-5), 48.4 (C-18), 45.4 (C-8), 44.1
(Gly-CNH), 43.8 (C-20), 43.2 (C-14), 41.0 (C-19), 38.7 (C-1), 38.1
(C-4), 37.7 (C-22), 36.9 (C-10), 32.7 (C-7), 31.8 (C-17), 31.1
(C-21), 28.5 (C-29), 28.3 (C-23), 28.1 (C-28), 26.5 (C-16), 26.4 (C-15),
23.6 (C-2), 23.3 (C-27), 18.6 (C-26), 17.3 (C-6), 16.7 (C-24), 16.4
m
(m), 1389 (m), 1362 (w), 1324 (m), 1278 (w), 1248 (m), 1218 (s),
1174 (s), 1087 (m), 1021 (w), 985 (m), 878 (w), 769 (w), 684 (w),
669 (w), 589 (w), 543 (w) cmꢃ1 1H NMR (500 MHz, CDCl3):
;
d = 5.64 (s, 1H, H-12), 4.55 (dd, 1H, H-3, J = 11.8, 4.87 Hz), 4.18
(dq, 1H, COOCHH0, J = 10.8, 7.17 Hz), 4.11 (dq, 1H, COOCHH0,
J = 10.8, 7.17 Hz), 2.98 (m, 2H, Ala-CH2NH2), 2.80 (ddd, 1H, H-1,
J = 13.7, 3.7, 3.77 Hz), 2.46 (t, 2H, Ala-CH2COO, J = 6.67 Hz), 2.36
(s, 1H, H-9), 2.09 (dd, 1H, H-18, J = 13.5, 3.67 Hz), 2.02 (ddd, 1H,
H-15, J = 13.5, 13.5, 4.47 Hz), 1.98 (m, 1H, H-21), 1.92 (ddd, 1H,
H-19, J = 13.6, 3.8, 2.97 Hz), 1.82 (ddd, 1H, H-16, J = 13.7, 13.7,
4.77 Hz), 1.71 (m, 1H, H-2), 1.67 (m, 1H, H-7), 1.60 (dd, 1H, H-
190, J = 13.6, 13.67 Hz), 1.60 (m, 1H, H-20), 1.58 (m, 1H, H-6), 1.46
(m, 1H, H-60), 1.41 (m, 1H, H-70), 1.38 (m, 1H, H-22), 1.36 (s, 3H,
H-27), 1.32 (m, 1H, H-220), 1.31 (m, 1H, H-210), 1.25 (t, 3H,
COOCH2CH3, J = 7.17 Hz), 1.17 (m, 1H, H-160), 1.16 (s, 3H, H-25),
1.13 (s, 3H, H-28), 1.12 (s, 3H, H-26), 1.05 (ddd, 1H, H-10, J = 13.5,
13.5, 3.57 Hz), 1.01 (m, 1H, H-150), 0.88 (s, 6H, H-23 and H-24),
0.80 (m, 1H, H-5), 0.79 (s, 3H, H-29); 13C NMR (125 MHz, CDCl3):
d = 200.0 (C-11), 176.4 (C-30), 172.4 (Ala-COO), 169.3
(C-13), 128.4 (C-12), 80.7 (C-3), 61.7 (C-9), 60.3 (COOCH2), 55.0

7466
S. Schwarz, R. Csuk / Bioorg. Med. Chem. 18 (2010) 7458–7474
(C-5), 48.4 (C-18), 45.4 (C-8), 43.8 (C-20), 43.2 (C-14), 41.0 (C-19),
38.7 (C-1), 38.4 (Ala-CH2COO), 38.0 (C-4 and Ala-CH2NH2), 37.7
(C-22), 36.9 (C-10), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21), 28.5
(C-29), 28.3 (C-28), 28.1 (C-23), 26.5 (C-16), 26.4 (C-15), 23.6
(C-2), 23.3 (C-27), 18.7 (C-26), 17.4 (C-6), 16.7 (C-24), 16.4
(C-25), 14.3 (COOCH2CH3). Anal. Calcd for C35H55NO5 (569.81): C,
73.77; H, 9.73; N, 2.46. Found: C, 73.62; H, 9.91; N, 2.32.
(C-5), 50.3 (Ala-CH), 48.4 (C-18), 45.4 (C-8), 43.7 (C-20), 43.2
(C-14), 41.1 (C-19), 38.7 (C-1), 38.2 (C-4), 37.7 (C-22), 36.9
(C-10), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21), 28.6 (C-29), 28.2
(C-23), 28.1 (C-28), 26.5 (C-16), 26.4 (C-15), 23.6 (C-2), 23.3
(C-27), 21.9 (i-Pr-CH3), 21.7 (i-Pr-CH3), 20.5 (Ala-CH3), 18.7
(C-26), 17.4 (C-6), 16.7 (C-24), 16.4 (C-25). Anal. Calcd for
C36H57NO7 (583.84): C, 74.06; H, 9.84; N, 2.40. Found: C, 73.99;
H, 10.01; N, 2.26.
4.2.6.14.
i-Propyl 3b-(glycyl)-11-oxo-olean-12-en-30-oate
(14). Obtained from 35 by method B as a colourless powder;
4.2.6.16.
i-Propyl 3b-(b-alanyl)-11-oxo-olean-12-en-30-oate
yield: 120 mg, 46%; mp 265–268 °C; Rf = 0.57 (DCM/MeOH 9:1);
(16). Obtained from 37 by method B as a colourless powder;
yield: 200 mg, 76%; mp 266–269 °C (decomp.); Rf = 0.19 (DCM/
½
a 2D0
ꢂ
= 122.07 (c 0.34, CHCl3); UV–vis (MeOH): kmax (log
250 nm (4.09); MS (ESI): m/z (%) = 570.3 ([M+H]+, 100), 855.3
([3M+2H]2+, 6); IR (KBr):
= 3404 (br), 2977 (s), 2858 (m), 1735
e) =
MeOH 9:1); ½a 2D0
ꢂ
= 120.18 (c 0.36, CHCl3); UV–vis (MeOH): kmax
m
(log e ,
) = 250 nm (4.08); MS (ESI): m/z (%) = 584.9 ([2M+2H]2+
(s), 1655 (s), 1466 (m), 1389 (m), 1328 (w), 1311 (w), 1218 (s),
1179 (s), 1144 (m), 1108 (m), 1086 (m), 1020 (w), 974 (w), 917
100); IR (KBr): m = 3388 (br), 2956 (s), 1722 (s), 1655 (s), 1466
(m), 1387 (m), 1218 (s), 1173 (m), 1141 (m), 1111 (m), 1085 (m),
(w), 849 (w), 669 (w), 543 (w) cmꢃ1 1H NMR (400 MHz, CDCl3):
;
1022 (w), 987 (w), 917 (w), 878 (w), 830 (w), 670 (w), 545 (w)
d = 5.60 (s, 1H, H-12), 5.01 (qq, 1H, i-Pr-CH, J = 6.2, 6.27 Hz), 4.56
(dd, 1H, H-3, J = 11.6, 4.97 Hz), 3.42 (s, 2H, Gly-CH2), 2.79 (ddd,
1H, H-1, J = 13.7, 3.5, 3.57 Hz), 2.34 (s, 1H, H-9), 2.08 (dd, 1H, H-
18, J = 13.5, 3.77 Hz), 2.01 (ddd, 1H, H-15, J = 13.3, 4.4, 4.47 Hz),
1.96 (m, 1H, H-21), 1.89 (ddd, 1H, H-19, J = 13.2, 3.6, 2.97 Hz),
1.80 (ddd, 1H, H-16, J = 14.2, 14.2, 4.77 Hz), 1.70 (m, 1H, H-2),
1.65 (m, 1H, H-7), 1.62 (m, 1H, H-20), 1.58 (dd, 1H,
H-190, J = 13.3, 13.37 Hz), 1.56 (m, 1H, H-6), 1.46 (m, 1H,
H-60), 1.41 (m, 1H, H-70), 1.36 (m, 1H, H-22), 1.34 (s, 3H, H-27),
1.33 (m, 1H, H-220), 1.27 (m, 1H, H-210), 1.23 (d, 3H, i-Pr-CH3,
J = 6.27 Hz), 1.20 (d, 3H, i-Pr-CH3, J = 6.27 Hz), 1.16 (m, 1H,
H-160), 1.14 (s, 3H, H-25), 1.10 (s, 6H, H-28 and H-26), 1.04 (ddd,
1H, H-10, J = 13.5, 13.5, 3.67 Hz), 0.99 (m, 1H, H-150), 0.85 (s, 6H,
H-23 and H-24), 0.79 (m, 1H, H-5), 0.77 (s, 3H, H-29); 13C NMR
(125 MHz, CDCl3): d = 200.0 (C-11), 175.8 (C-30), 173.9 (Gly-
COO), 169.5 (C-13), 128.4 (C-12), 81.4 (C-3), 67.3 (i-Pr-CH), 61.7
(C-9), 55.0 (C-5), 48.4 (C-18), 45.4 (C-8), 44.0 (C-20), 43.7 (Gly-
CH2), 43.2 (C-14), 41.0 (C-19), 38.7 (C-1), 38.1 (C-4), 37.7 (C-22),
36.9 (C-10), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21), 28.6 (C-29), 28.2
(C-23), 28.1 (C-28), 26.5 (C-16), 26.4 (C-15), 23.6 (C-2), 23.3
(C-27), 21.9 (i-Pr-CH3), 21.7 (i-Pr-CH3), 18.6 (C-26), 17.3 (C-6),
16.7 (C-24), 16.4 (C-25). Anal. Calcd for C35H55NO5 (569.81): C,
73.77; H, 9.73; N, 2.46. Found: C, 73.56; H, 9.93; N, 2.34.
cmꢃ1 1H NMR (500 MHz, CDCl3): d = 5.60 (s, 1H, H-12), 5.01 (qq,
;
1H, i-Pr-CH, J = 6.2, 6.27 Hz), 4.53 (dd, 1H, H-3, J = 11.7, 4.57 Hz),
2.98 (m, 2H, Ala-CH2NH2), 2.78 (ddd, 1H, H-1, J = 13.2, 3.3,
3.37 Hz), 2.47 (t, 2H, Ala-CH2COO, J = 5.47 Hz), 2.34 (s, 1H, H-9),
2.08 (dd, 1H, H-18, J = 13.3, 3.37 Hz), 2.01 (ddd, 1H, H-15,
J = 13.7, 13.7, 4.77 Hz), 1.96 (m, 1H, H-21), 1.89 (ddd, 1H, H-19,
J = 13.3, 3.7, 2.57 Hz), 1.80 (ddd, 1H, H-16, J = 14.1, 14.1, 4.77 Hz),
1.71 (m, 1H, H-2), 1.66 (m, 1H, H-7), 1.60 (m, 1H, H-20), 1.58 (dd,
1H, H-190, J = 13.5, 13.57 Hz), 1.56 (m, 1H, H-6), 1.44 (m, 1H,
H-60), 1.38 (m, 1H, H-70), 1.35 (m, 1H, H-22), 1.34 (s, 3H, H-27),
1.34 (m, 1H, H-220), 1.32 (m, 1H, H-210), 1.23 (d, 3H, i-Pr-CH3,
J = 6.27 Hz), 1.20 (d, 3H, i-Pr-CH3, J = 6.27 Hz), 1.16 (m, 1H,
H-160), 1.14 (s, 3H, H-25), 1.10 (s, 6H, H-28 and H-26), 1.03 (m,
1H, H-10), 0.99 (m, 1H, H-150), 0.86 (s, 6H, H-23 and H-24), 0.79
(m, 1H, H-5), 0.77 (s, 3H, H-29); 13C NMR (125 MHz, CDCl3):
d = 200.0 (C-11), 175.8 (C-30), 172.3 (Ala-COO), 169.4 (C-13),
128.4 (C-12), 80.8 (C-3), 67.3 (i-Pr-CH), 61.7 (C-9), 55.0 (C-5),
48.4 (C-18), 45.4 (C-8), 43.7 (C-20), 43.2 (C-14), 41.0 (C-19), 38.7
(C-1), 38.5 (Ala-CH2COO), 38.0 (C-4 and Ala-CH2NH2), 37.7
(C-22), 36.9 (C-10), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21), 28.6
(C-29), 28.2 (C-28), 28.1 (C-23), 26.5 (C-16), 26.4 (C-15), 23.6
(C-2), 23.3 (C-27), 21.9 (i-Pr-CH3), 21.7 (i-Pr-CH3), 18.6 (C-26),
17.4 (C-6), 16.7 (C-24), 16.3 (C-25). Anal. Calcd for C36H57NO5
(583.84): C, 74.33; H, 9.95; N, 2.34. Found: C, 74.21; H, 10.07; N,
2.28.
4.2.6.15.
i-Propyl 3b-(L-alanyl)-11-oxo-olean-12-en-30-oate
(15). Obtained from 36 by method B as a colourless powder;
yield: 160 mg, 96%; mp 249–252 °C; Rf = 0.56 (DCM/MeOH 9:1);
4.2.6.17.
Benzyl
3b-(glycyl)-11-oxo-olean-12-en-30-oate
½
a 2D0
ꢂ
= 114.82 (c 0.32, CHCl3); UV–vis (MeOH): kmax (log
249 nm (4.10); MS (ESI): m/z (%) = 584.3 ([M+H]+, 100); IR (KBr):
= 3426 (br), 2976 (s), 2874 (s), 1725 (s), 1657 (s), 1619 (m),
e
) =
(17). Obtained from 38 by method B as a colourless powder;
yield: 200 mg, 89%; mp 186–190 °C; Rf = 0.58 (DCM/MeOH 9:1);
m
½
a 2D0
ꢂ
= 123.22 (c 0.56, CHCl3); UV–vis (MeOH): kmax (log
= 249 nm (4.05); MS (ESI): m/z (%) = 618.3 ([2M+2H]2+, 100),
927.3 ([3M+3H]2+, 5); IR (KBr):
= 3393 (br), 2951 (s), 2874 (m),
e)
1466 (m), 1387 (m), 1374 (m), 1325 (m), 1280 (m), 1258 (m),
1216 (s), 1174 (s), 1142 (m), 1109 (s), 1086 (m), 1048 (w), 1021
(w), 983 (m), 948 (w), 916 (w), 880 (w), 847 (w), 770 (w), 686
m
1731 (s), 1655 (s), 1618 (w), 1498 (w), 1456 (m), 1388 (m), 1365
(m), 1324 (m), 1214 (s), 1147 (s), 1085 (m), 1049 (w), 1028 (w),
985 (m), 916 (w), 880 (w), 767 (w), 748 (w), 697 (w), 670 (w),
(w), 671 (w), 589 (w), 544 (w) cmꢃ1 1H NMR (400 MHz, CDCl3):
;
d = 5.61 (s, 1H, H-12), 5.02 (qq, 1H, i-Pr-CH, J = 6.2, 6.27 Hz), 4.51
(dd, 1H, H-3, J = 11.8, 4.67 Hz), 3.57 (q, 1H, Ala-CH, J = 7.17 Hz),
2.79 (ddd, 1H, H-1, J = 13.5, 3.5, 3.57 Hz), 2.35 (s, 1H, H-9), 2.09
(dd, 1H, H-18, J = 13.5, 3.17 Hz), 2.01 (m, 1H, H-15), 1.96 (m, 1H,
H-21), 1.89 (m, 1H, H-19), 1.80 (m, 1H, H-16), 1.71 (m, 1H, H-2),
1.64 (m, 1H, H-7), 1.60 (m, 1H, H-20), 1.58 (dd, 1H, H-190, J = 13.5,
13.57 Hz), 1.56 (m, 1H, H-6), 1.44 (m, 1H, H-60), 1.41 (m, 1H, H-
70), 1.36 (m, 1H, H-22), 1.35 (s, 3H, H-27), 1.31 (d, 3H, Ala-CH3,
J = 7.07 Hz), 1.31 (m, 1H, H-220), 1.30 (m, 1H, H-210), 1.23 (d, 3H,
i-Pr-CH3, J = 6.27 Hz), 1.20 (d, 3H, i-Pr-CH3, J = 6.27 Hz), 1.18 (m, 1H,
H-160), 1.15 (s, 3H, H-25), 1.11 (s, 6H, H-28 and H-26), 1.04
(m, 1H, H-10), 0.99 (m, 1H, H-150), 0.88 (s, 3H, H-23), 0.86 (s, 3H,
H-24), 0.79 (m, 1H, H-5), 0.78 (s, 3H, H-29); 13C NMR (125 MHz,
CDCl3): d = 200.0 (C-11), 176.2 (C-30), 175.8 (Ala-COO), 169.5
(C-13), 128.4 (C-12), 81.3 (C-3), 67.4 (i-Pr-CH), 61.7 (C-9), 55.0
586 (w), 542 (w) cmꢃ1 1H NMR (400 MHz, CDCl3): d = 7.38–7.28
;
(m, 5H, H-Ar), 5.53 (s, 1H, H-12), 5.18 (d, 1H, Bn-CHH0,
J = 12.67 Hz), 5.07 (d, 1H, Bn-HH0, J = 12.17 Hz), 4.56 (dd, 1H, H-3,
J = 11.5, 4.77 Hz), 3.41 (s, 2H, Gly-CH2), 2.79 (ddd, 1H, H-1,
J = 13.6, 3.6, 3.67 Hz), 2.32 (s, 1H, H-9), 2.02 (m, 1H, H-18), 2.00
(m, 1H, H-15), 1.97 (m, 1H, H-21), 1.92 (dd, 1H, H-19, J = 13.0,
3.8, 2.97 Hz), 1.79 (ddd, 1H, H-16, J = 14.0, 14.0, 4.57 Hz), 1.70
(m, 1H, H-2), 1.65 (m, 1H, H-7), 1.62 (m, 1H, H-20), 1.60 (dd, 1H,
H-190, J = 13.2, 13.27 Hz), 1.56 (m, 1H, H-6), 1.45 (m, 1H, H-60),
1.40 (m, 1H, H-70), 1.35 (m, 1H, H-22), 1.33 (s, 3H, H-27), 1.30
(m, 1H, H-210), 1.28 (m, 1H, H-220), 1.15 (m, 1H, H-160), 1.14 (s,
6H, H-28 and H-25), 1.09 (s, 3H, H-26), 1.04 (m, 1H, H-10), 0.98
(m, 1H, H-150), 0.86 (s, 6H, H-23 and H-24), 0.78 (m, 1H, H-5),
0.71 (s, 3H, H-29); 13C NMR (125 MHz, CDCl3): d = 199.9 (C-11),

S. Schwarz, R. Csuk / Bioorg. Med. Chem. 18 (2010) 7458–7474
7467
176.2 (C-30), 174.0 (Gly-COO), 169.1 (C-13), 136.1 (Car), 128.6
(C-12), 128.6 (Car), 128.4 (Car), 128.3 (Car), 128.2 (Car), 128.2 (Car),
81.3 (C-3), 66.2 (Bn-CH2), 61.6 (C-9), 55.0 (C-5), 48.2 (C-18), 45.3
(C-8), 44.1 (Gly-CH2), 44.0 (C-20), 43.2 (C-14), 41.0 (C-19), 38.7
(C-1), 38.1 (C-4), 37.6 (C-22), 36.9 (C-10), 32.7 (C-7), 31.8 (C-17),
31.2 (C-21), 28.4 (C-29), 28.3 (C-23), 28.1 (C-28), 26.4 (C-16),
26.4 (C-15), 23.6 (C-2), 23.3 (C-27), 18.6 (C-26), 17.4 (C-6), 16.7
(C-24), 16.4 (C-25). Anal. Calcd for C39H55NO5 (617.86): C, 75.81;
H, 8.97; N, 2.27. Found: C, 75.77; H, 9.12; N, 2.16.
1H, H-160), 1.14 (s, 6H, H-25 and H-28), 1.09 (s, 3H, H-26), 1.02
(ddd, 1H, H-10, J = 13.3, 13.3, 3.77 Hz), 0.97 (m, 1H, H-150), 0.86
(s, 6H, H-23 and H-24), 0.78 (m, 1H, H-5), 0.71 (s, 3H, H-29); 13C
NMR (125 MHz, CDCl3): d = 199.9 (C-11), 176.2 (C-30), 172.0
(Ala-COO), 169.1 (C-13), 136.1 (Car), 128.6 (Car), 128.5 (C-12),
128.6 (Car), 128.3 (Car), 128.2 (Car), 128.2 (Car), 81.4 (C-3), 66.2
(Bn-CH2), 61.6 (C-9), 55.0 (C-5), 48.2 (C-18), 45.3 (C-8), 44.0
(C-20), 43.2 (C-14), 41.1 (C-19), 38.8 (C-1), 38.7 (Ala-CH2COO),
38.1 (C-4), 38.1 (Ala-CH2NH2), 37.6 (C-22), 36.9 (C-10), 32.7
(C-7), 31.8 (C-17), 31.2 (C-21), 28.4 (C-29), 28.3 (C-23), 28.1
(C-28), 26.5 (C-16), 26.4 (C-15), 23.6 (C-2), 23.3 (C-27), 18.7
(C-26), 17.4 (C-6), 16.7 (C-24), 16.4 (C-25). Anal. Calcd for
4.2.6.18. Benzyl
3b-(L-alanyl)-11-oxo-olean-12-en-30-oate
(18). Obtained from 39 by method B as a colourless powder;
yield: 330 mg, 98%; mp 200–203 °C; Rf = 0.58 (DCM/MeOH 9:1);
C
40H57NO5 (631.88): C, 76.03; H, 9.09; N, 2.22. Found: C, 75.79;
½
a 2D0
ꢂ
= 128.39 (c 0.52, CHCl3); UV–vis (MeOH): kmax (log
207 nm (4.08), 249 nm (4.10); MS (ESI): m/z (%) = 632.2
e
) =
H, 9.21; N, 2.11.
([2M+2H]2+, 100), 948.2 ([3M+2H]2+, 10), 1263.7 ([2M+H]+, 4); IR
4.2.6.20. Methyl 3b-(glycyl)-11-oxo-olean-12-en-30-oate hydro-
chloride (20). Obtained from 29 by method D as a colourless
powder; yield:130 mg, 48%; mp 288–292 °C (decomp.); Rf = 0.54
(KBr):
m = 3369 (br), 2958 (s), 2874 (m), 1728 (s), 1652 (s), 1616
(w), 1498 (w), 1455 (m), 1389 (m), 1368 (w), 1324 (m), 1278
(w), 1263 (w), 1214 (s), 1190 (s), 1146 (s), 1085 (m), 1063 (m),
1050 (w), 1029 (m), 972 (w), 916 (w), 890 (w), 868 (w), 850 (w),
768 (w), 742 (m), 696 (w), 613 (w), 587 (w), 544 (w), 471 (w)
(MeOH); ½a 2D0
ꢂ
= 130.16 (c 0.39, CH2Cl2); UV–vis (MeOH): kmax
(log e ,
) = 249 nm (4.03); MS (ESI): m/z (%) = 542.3 ([2M+2H]2+
100), 812.9 ([3M+2H]2+
,
12), 1083.1 ([2M+H]+, 6); IR (KBr):
cmꢃ1
;
1H NMR (400 MHz, CDCl3): d = 7.38–7.28 (m, 5H, H-Ar),
m = 3439 (br), 2951 (s), 1731 (s), 1657 (s), 1618 (m), 1466 (s),
5.52 (s, 1H, H-12), 5.18 (d, 1H, Bn-CHH0, J = 12.57 Hz), 5.06 (d,
1H, Bn-CHH0, J = 12.37 Hz), 4.53 (dd, 1H, H-3, J = 11.7, 4.87 Hz),
3.52 (q, 1H, Ala-CH, J = 7.17 Hz), 2.79 (ddd, 1H, H-1, J = 13.6,
3.4, 3.47 Hz), 2.32 (s, 1H, H-9), 2.01 (m, 1H, H-18), 1.99 (m, 1H,
H-15), 1.96 (m, 1H, H-21), 1.92 (m, 1H, H-19), 1.78 (ddd, 1H,
H-16, J = 13.7, 13.7, 4.67 Hz), 1.70 (m, 1H, H-2), 1.65 (m, 1H,H-7),
1.62 (m, 1H, H-20), 1.59 (dd, 1H, H-190, J = 13.3, 13.37 Hz), 1.57
(m, 1H, H-6), 1.44 (m, 1H, H-60), 1.37 (m, 1H, H-70), 1.34 (m, 1H,
H-22), 1.34 (m, 3H, Ala-CH3), 1.33 (s, 3H, H-27), 1.29 (m, 2H, H-
220 and H-210), 1.15 (m, 1H, H-160), 1.14 (s, 6H, H-25 and
H-28), 1.09 (s, 3H, H-26), 1.03 (ddd, 1H, H-10, J = 13.3, 13.3,
3.37 Hz), 0.97 (m, 1H, H-150), 0.87 (s, 3H, H-23), 0.85 (s, 3H,
H-24), 0.79 (m, 1H, H-5), 0.71 (s, 3H, H-29); 13C NMR (125 MHz,
CDCl3): d = 200.0 (C-11), 176.3 (C-30), 176.2 (Ala-COO), 169.0
(C-13), 136.1 (Car), 128.6 (Car), 128.6 (Car), 128.4 (C-12), 128.3
(Car), 128.2 (Car), 128.2 (Car), 81.1 (C-3), 66.2 (Bn-CH2), 61.6 (C-9),
55.0 (C-5), 50.4 (Ala-CH), 48.2 (C-18), 45.3 (C-8), 44.0 (C-20),
43.2 (C-14), 41.1 (C-19), 38.7 (C-1), 38.2 (C-4), 37.6 (C-22), 36.9
(C-10), 32.7 (C-7), 31.8 (C-17), 31.2 (C-21), 28.4 (C-29), 28.3
(C-23), 28.1 (C-28), 26.4 (C-16), 26.4 (C-15), 23.6 (C-2), 23.3
(C-27), 20.8 (Ala-CH3), 18.7 (C-26), 17.3 (C-6), 16.7 (C-24), 16.4
(C-25). Anal. Calcd for C40H57NO5 (631.88): C, 76.03; H, 9.09; N,
2.22. Found: C, 75.87; H, 9.12; N, 2.17.
1432 (m), 1389 (m), 1323 (m), 1244 (s), 1155 (s), 1087 (m), 1049
(m), 987 (m), 911 (w), 880 (w), 825 (w), 770 (w), 686 (w), 670
(s), 590 (w), 544 (w), 501 (w) cmꢃ1 1H NMR (400 MHz, MeOH-
;
d4): d = 5.57 (s, 1H, H-12), 4.68 (dd, 1H, H-3, J = 11.9, 4.77 Hz),
3.84 (dd, 2H, Gly-CH2, J = 26.5, 7.07 Hz), 3.69 (s, 3H, OMe), 2.79
(ddd, 1H, H-1, J = 13.8, 3.7, 3.77 Hz), 2.49 (s, 1H, H-9), 2.14 (m, 1H,
H-15), 2.12 (dd, 1H, H-18, J = 13.3, 4.17 Hz), 1.96 (m, 1H, H-21),
1.88 (ddd, 1H, H-16, J = 13.7, 13.7, 4.37 Hz), 1.86 (m, 1H, H-19),
1.81 (m, 1H, H-2), 1.77 (m, 1H, H-7), 1.73 (dd, 1H, H-190, J = 13.3,
13.37 Hz), 1.67 (m, 1H, H-20), 1.64 (m, 1H, H-6), 1.53 (m, 1H,
H-60), 1.47 (m, 1H, H-70), 1.44 (m, 1H, H-22), 1.43 (s, 3H, H-27),
1.41 (m, 1H, H-210), 1.28 (m, 1H, H-220), 1.24 (m, 1H, H-160), 1.17
(s, 3H, H-25), 1.14 (s, 6H, H-26 and H-28), 1.12 (m, 1H, H-10),
1.04 (m, 1H, H-150), 0.94 (s, 3H, H-23), 0.93 (s, 3H, H-24), 0.91
(m, 1H, H-5), 0.82 (s, 3H, H-29); 13C NMR (125 MHz, MeOH-d4):
d = 202.2 (C-11), 178.6 (C-30), 172.7 (Gly-COO), 168.4 (C-13),
128.9 (C-12), 84.6 (C-3), 62.9 (C-9), 56.0 (C-5), 52.3 (OMe), 49.9
(C-18), 46.7 (C-8), 44.7 (C-20), 44.6 (C-14), 42.4 (C-19), 41.1 (Gly-
CH2), 39.6 (C-1), 39.2 (C-4), 39.0 (C-22), 38.2 (C-10), 33.6 (C-7),
33.0 (C-17), 32.0 (C-21), 29.1 (C-29), 28.5 (C-23), 28.5 (C-28),
27.6 (C-16), 27.3 (C-15), 24.4 (C-2), 23.8 (C-27), 19.3 (C-26), 18.4
(C-6), 17.1 (C-24), 16.9 (C-25). Anal. Calcd for
C33H52ClNO5
(578.22): C, 68.55; H, 9.06; Cl, 6.13; N, 2.42. Found: C, 68.49; H,
9.27; Cl, 6.27; N, 2.13.
4.2.6.19.
Benzyl
3b-(b-alanyl)-11-oxo-olean-12-en-30-oate
(19). Obtained from 40 by method B as a colourless powder;
yield: 150 mg, 91%; mp 233–236 °C (decomp.); Rf = 0.20 (DCM/
4.2.6.21. Methyl
3b-(L-alanyl)-11-oxo-olean-12-en-30-oate
hydrochloride (21). Obtained from 30 by method D as a colour-
less powder; yield: 180 mg, 56%; mp 288–292 °C (decomp.);
MeOH 9:1); ½a 2D0
ꢂ
= 114.31 (c 0.59, CHCl3); UV–vis (MeOH): kmax (lo-
) = 207 nm (4.02), 250 nm (4.08); MS (ESI): m/z (%) = 632.3
g
e
Rf = 0.61 (MeOH); ½a D20
ꢂ
= 125.80 (c 0.36, MeOH); UV–vis (MeOH):
([M+H]+, 100); IR (KBr):
m
= 3424 (br), 2949 (s), 2872 (m), 1727
kmax (log e
) = 249 nm (4.02); MS (ESI): m/z (%) = 556.2 ([M+H]+,
(s), 1657 (s), 1456 (m), 1387 (m), 1367 (m), 1324 (m), 1279 (m),
1248 (m), 1213 (s), 1148 (s), 1085 (m), 1048 (w), 1023 (w), 986
(m), 915 (w), 880 (w), 830 (w), 754 (w), 698 (m), 670 (w), 586
100), 833.8 ([3M+2H]2+, 10); IR (KBr):
m = 3441 (br), 2951 (s),
2362 (w), 1743 (s), 1730 (s), 1661 (s), 1622 (w), 1517 (m), 1466
(m), 1387 (m), 1322 (w), 1257 (m), 1217 (m), 1191 (m), 1153
(m), 1122 (m), 1086 (w), 1049 (s), 985 (m), 914 (w), 867 (m),
(w), 543 (w) cmꢃ1 1H NMR (400 MHz, CDCl3): d = 7.38–7.28 (m,
;
5H, H-Ar), 5.52 (s, 1H, H-12), 5.18 (d, 1H, Bn-CHH0, J = 12.27 Hz),
5.06 (d, 1H, Bn-CHH0, J = 12.27 Hz), 4.54 (dd, 1H, H-3, J = 11.7,
5.17 Hz), 3.10 (m, 2H, Ala-CH2NH2), 2.79 (ddd, 1H, H-1, J = 13.7,
3.7, 3.77 Hz), 2.61 (m, 2H, Ala-CH2COO), 2.32 (s, 1H, H-9), 2.01
(m 1H, H-18), 1.99 (m, 1H, H-15), 1.97 (m, 1H, H-21), 1.92 (ddd,
1H, H-19, J = 13.3, 3.7, 2.97 Hz), 1.78 (ddd, 1H, H-16, J = 13.7,
13.7, 4.27 Hz), 1.70 (m, 1H, H-2), 1.65 (m, 1H, H-7), 1.60 (m, 1H,
H-20), 1.60 (dd, 1H, H-190, J = 13.5, 13.57 Hz), 1.56 (m, 1H, H-6),
1.44 (m, 1H, H-60), 1.38 (m, 1H, H-70), 1.34 (m, 1H, H-22), 1.33
(s, 3H, H-27), 1.30 (m, 1H, H-220), 1.27 (m, 1H, H-210), 1.16 (m,
823 (w), 769 (w), 670 (w), 546 (w) cmꢃ1 1H NMR (400 MHz,
;
MeOH-d4): d = 5.58 (s, 1H, H-12), 4.67 (dd, 1H, H-3, J = 11.7,
5.07 Hz), 4.10 (q, 1H, Ala-CH, J = 7.47 Hz), 3.69 (s, 3H, OMe), 2.80
(ddd, 1H, H-1, J = 13.3, 3.3, 3.37 Hz), 2.50 (s, 1H, H-9), 2.16 (m,
1H, H-15), 2.13 (m, 1H, H-18), 1.97 (m, 1H, H-21), 1.90 (m, 1H,
H-16), 1.84 (m, 1H, H-19), 1.81 (m, 1H, H-2), 1.77 (m, 1H, H-7),
1.72 (dd, 1H, H-190, J = 13.2, 13.27 Hz), 1.68 (m, 1H, H-20), 1.66
(m, 1H, H-6), 1.51 (m, 1H, H-60), 1.47 (m, 1H, H-70), 1.41 (m, 1H,
H-22), 1.43 (s, 3H, H-27), 1.44 (m, 1H, H-210), 1.56 (d, 3H,
Ala-CH3, J = 7.37 Hz), 1.29 (m, 1H, H-220), 1.25 (m, 1H, H-160),

7468
S. Schwarz, R. Csuk / Bioorg. Med. Chem. 18 (2010) 7458–7474
1.18 (s, 3H, H-25), 1.15 (s, 6H, H-26 and H-28), 1.12 (m, 1H, H-10),
1.04 (m, 1H, H-150), 0.95 (s, 3H, H-24), 0.93 (s, 3H, H-23), 0.92 (m,
1H, H-5), 0.82 (s, 3H, H-29); 13C NMR (125 MHz, MeOH-d4):
d = 200.8 (C-11), 177.2 (C-30), 171.3 (Ala-COO), 169.4 (C-13),
127.5 (C-12), 83.2 (C-3), 61.4 (C-9), 54.5 (C-5), 50.9 (OMe), 48.5
(Ala-CH), 48.1 (C-18), 45.3 (C-8), 43.9 (C-20), 43.2 (C-14), 40.9
(C-19), 38.2 (C-1), 37.9 (C-4), 37.5 (C-22), 36.8 (C-10), 32.2 (C-7),
31.5 (C-17), 30.6 (C-21), 27.7 (C-29), 27.1 (C-23), 27.1 (C-28),
26.1 (C-16), 25.9 (C-15), 23.0 (C-2), 22.4 (C-27), 17.8 (C-26), 17.0
(C-6), 15.7 (C-24), 15.5 (C-25), 15.0 (Ala-CH3). Anal. Calcd for
0.86 (s, 3H, H-24), 0.79 (m, 1H, H-5), 0.78 (s, 3H, H-29); 13C NMR
(125 MHz, CDCl3): d = 200.0 (C-11), 176.9 (C-30), 176.1
(Ala-COO), 169.2 (C-13), 128.5 (C-12), 81.1 (C-3), 61.7 (C-9), 55.0
(C-5), 51.7 (OMe), 50.2 (Ala-CH), 48.4 (C-18), 45.4 (C-8), 44.0
(C-20), 43.2 (C-14), 41.1 (C-19), 38.7 (C-1), 38.1 (C-4), 37.7
(C-22), 36.9 (C-10), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21), 28.5
(C-29), 28.3 (C-23), 28.1 (C-28), 26.4 (C-16), 26.4 (C-15), 23.4
(C-2), 23.3 (C-27), 20.6 (Ala-CH3), 18.6 (C-26), 17.3 (C-6), 16.7
(C-24), 16.4 (C-25). Anal. Calcd for C34H53NO5 (555.79): C, 73.47;
H, 9.61; N, 2.52. Found: C, 73.41; H, 9.77; N, 2.49.
C34H54ClNO5 (592.25): C, 68.95; H, 9.19; Cl, 5.99; N, 2.37. Found:
C, 68.68; H, 9.25; Cl, 6.09; N, 2.22.
4.2.6.24. Ethyl
3b-(D-alanyl)-11-oxo-olean-12-en-30-oate
(24). Obtained from 42 by method B as a colourless powder;
yield: 240 mg, 86%; mp 236–239 °C; Rf = 0.58 (DCM/MeOH 9:1);
4.2.6.22.
Methyl
3b-(b-alanyl)-11-oxo-olean-12-en-30-oate
hydrochloride (22). Obtained from 31 by method D as a colour-
less powder; yield: 160 mg, 76%; mp 282–285 °C (decomp.);
½
a 2D0
ꢂ
= 108.78 (c 0.33, CHCl3); UV–vis (MeOH): kmax (log
249 nm (4.06); MS (ESI): m/z (%) = 570.3 ([M+H]+, 100), 854.8
([3M+2Na]2+, 10), 1139.2 ([2M+H]+, 4); IR (KBr):
= 3387 (br),
e) =
Rf = 0.19 (MeOH); ½a D20
ꢂ
= 128.78 (c 0.45, MeOH); UV–vis (MeOH):
m
kmax (log
e
) = 247 nm (4.17); MS (ESI): m/z (%) = 556.2 ([M+H]+,
2958 (s), 2874 (m), 1725 (s), 1653 (s), 1626 (m), 1454 (m), 1389
(m), 1323 (w), 1279 (w), 1246 (m), 1216 (s), 1177 (s), 1087 (m),
1049 (w), 1022 (w), 984 (w), 972 (w), 916 (w), 878 (w), 841 (w),
100), 834.3 ([3M+2H]2+
,
10), 1111.1 ([2M+H]+, 4); IR (KBr):
m
= 3437 (br), 2951 (s), 2034 (w), 1729 (s), 1660 (s), 1619 (m),
1465 (s), 1387 (m), 1323 (m), 1279 (m), 1218 (s), 1154 (s), 1108
755 (w), 670 (w), 544 (w) cmꢃ1 1H NMR (400 MHz, CDCl3):
;
(m), 1087 (m), 1049 (w), 1013 (w), 989 (s), 916 (w), 862 (w), 824
d = 5.62 (s, 1H, H-12), 4.51 (dd, 1H, H-3, J = 11.6, 4.77 Hz), 4.16
(dq, 1H, COOCHH0, J = 10.8, 7.17 Hz), 4.11 (dq, 1H, COOCHH0,
J = 10.8, 7.17 Hz), 3.54 (q, 1H, Ala-CH, J = 7.17 Hz), 2.79 (ddd, 1H,
H-1, J = 13.8, 3.5, 3.57 Hz), 2.34 (s, 1H, H-9), 2.08 (dd, 1H, H-18,
J = 13.3, 3.37 Hz), 2.01 (ddd, 1H, H-15, J = 13.8, 13.8, 4.57 Hz),
1.97 (m, 1H, H-21), 1.90 (m, 1H, H-19), 1.80 (ddd, 1H, H-16,
J = 13.6, 13.6, 4.67 Hz), 1.71 (m, 1H, H-2), 1.66 (m, 1H, H-7), 1.60
(m, 1H, H-20), 1.59 (dd, 1H, H-190, J = 13.4, 13.47 Hz), 1.56 (m, 1H,
H-6), 1.44 (m, 1H, H-60), 1.39 (m, 1H, H-70), 1.36 (m, 1H, H-22),
1.34 (s, 3H, H-27), 1.32 (d, 3H, Ala-CH3, J = 7.17 Hz), 1.29 (m, 1H,
H-220), 1.27 (m, 1H, H-210), 1.24 (t, 3H, Et-CH3, J = 7.17 Hz), 1.16
(m, 1H, H-160), 1.14 (s, 3H, H-25), 1.12 (s, 3H, H-28), 1.10 (s, 3H,
H-26), 1.04 (m, 1H, H-10), 0.99 (m, 1H, H-150), 0.87 (s, 3H, H-24),
0.86 (s, 3H, H-24), 0.80 (m, 1H, H-5), 0.78 (s, 3H, H-29); 13C NMR
(125 MHz, CDCl3): d = 200.0 (C-11), 176.3 (C-30), 176.1
(Ala-COO), 169.4 (C-13), 128.4 (C-12), 81.2 (C-3), 61.7 (C-9), 60.3
(Et-CH2), 55.0 (C-5), 50.2 (Ala-CH), 48.4 (C-18), 45.4 (C-8), 43.8
(C-20), 43.2 (C-14), 41.1 (C-19), 38.7 (C-1), 38.1 (C-4), 37.7
(C-22), 36.9 (C-10), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21), 28.5
(C-29), 28.3 (C-23), 28.1 (C-28), 26.5 (C-16), 26.4 (C-15), 23.4
(C-2), 23.3 (C-27), 20.7 (Ala-CH3), 18.7 (C-26), 17.3 (C-6), 16.7
(C-24), 16.4 (C-25), 14.3 (Et-CH3). Anal. Calcd for C35H55NO5
(569.81): C, 73.77; H, 9.73; N, 2.46. Found: C, 73.56; H, 9.87; N,
2.42.
(w), 788 (w), 770 (w), 670 (w), 590 (w), 544 (w) cmꢃ1 1H NMR
;
(500 MHz, CDCl3): d = 5.56 (s, 1H, H-12), 4.57 (dd, 1H, H-3,
J = 11.8, 4.77 Hz), 3.67 (s, 3H, OMe), 3.18 (m, 2H, Ala-CH2NH2),
2.74 (m, 1H, H-1), 2.72 (m, 2H, Ala-CH2COO), 2.47 (s, 1H, H-9),
2.13 (m, 1H, H-15), 2.11 (m, 1H, H-18), 1.95 (m, 1H, H-21), 1.86
(m, 1H, H-16), 1.84 (m, 1H, H-19), 1.73 (m, 1H, H-2), 1.71 (dd,
1H, H-190, J = 13.3, 13.37 Hz), 1.66 (m, 1H, H-7), 1.63 (m, 1H,
H-20), 1.61 (m, 1H, H-6), 1.51 (m, 1H, H-60), 1.45 (m, 1H, H-70),
1.41 (s, 3H, H-27), 1.40 (m, 1H, H-22), 1.28 (m, 1H, H-210), 1.25
(m, 1H, H-220), 1.23 (m, 1H, H-160), 1.15 (s, 3H, H-25), 1.13 (s,
6H, H-28 and H-26), 1.09 (m, 1H, H-10), 1.03 (m, 1H, H-150), 0.90
(s, 6H, H-23 and H-24), 0.88 (m, 1H, H-5), 0.80 (s, 3H, H-29); 13C
NMR (125 MHz, CDCl3): d = 200.9 (C-11), 177.2 (C-30), 171.3
(Ala-COO), 170.6 (C-13), 127.5 (C-12), 81.8 (C-3), 61.5 (C-9), 54.7
(C-5), 50.9 (OMe), 48.5 (C-18), 45.3 (C-8), 43.9 (C-20), 43.2
(C-14), 40.9 (C-19), 38.3 (C-1), 37.7 (C-4), 37.5 (C-22), 36.8
(C-10), 35.0 (Ala-CH2NH2), 32.2 (C-7), 31.5 (C-17), 30.9
(Ala-CH2COO), 30.6 (C-21), 27.7 (C-29), 27.1 (C-28), 27.1 (C-23),
26.1 (C-16), 25.9 (C-15), 23.0 (C-2), 22.4 (C-27), 17.8 (C-26), 17.0
(C-6), 15.7 (C-24), 15.5 (C-25). Anal. Calcd for
C34H54ClNO5
(592.25): C, 68.95; H, 9.19; Cl, 5.99; N, 2.37. Found: C, 68.87; H,
9.32; Cl, 6.12; N, 2.24.
4.2.6.23. Methyl
3b-(D-alanyl)-11-oxo-olean-12-en-30-oate
(23). Obtained from 41 by method B as a colourless powder;
4.2.6.25.
i-Propyl 3b-(D-alanyl)-11-oxo-olean-12-en-30-oate
yield: 220 mg, 76%; mp 243–247 °C; Rf = 0.58 (DCM/MeOH 9:1);
(25). Obtained from 43 by method B as a colourless powder;
yield: 200 mg, 90%; mp 263–266 °C; Rf = 0.59 (DCM/MeOH 9:1);
½
a 2D0
ꢂ
= 123.94 (c 0.28, CHCl3); UV–vis (MeOH): kmax (log
250 nm (4.08); MS (ESI): m/z (%) = 556.7 ([2M+2H]2+, 100); IR
(KBr): = 3387 (br), 2958 (s), 2874 (m), 1731 (s), 1652 (s), 1455
e) =
½
a 2D0
ꢂ
= 113.51 (c 0.24, CHCl3); UV–vis (MeOH): kmax (log
250 nm (4.07); MS (ESI): m/z (%) = 584.1 ([M+H]+, 100), 876.3
([3M+3Na]2+, 8), 1167.3 ([2M+H]+, 4); IR (KBr):
= 3420 (br),
e) =
m
(m), 1389 (m), 1323 (w), 1279 (w), 1248 (m), 1218 (m), 1190
(m), 1160 (m), 1087 (w), 1050 (w), 1022 (w), 985 (w), 973 (m),
917 (w), 867 (w), 825 (w), 770 (w), 669 (w), 590 (w), 544 (w)
m
2971 (s), 2875 (s), 1721 (s), 1652 (s), 1455 (m), 1388 (m), 1313
(m), 1279 (m), 1217 (s), 1180 (s), 1142 (m), 1108 (s), 1086 (m),
1021 (w), 986 (m), 972 (m), 917 (m), 879 (w), 848 (w), 770 (w),
cmꢃ1 1H NMR (400 MHz, CDCl3): d = 5.64 (s, 1H, H-12), 4.51 (dd,
;
1H, H-3, J = 11.6, 4.87 Hz), 3.66 (s, 3H, OMe), 3.53 (q, 1H, Ala-CH,
J = 7.07 Hz), 2.79 (ddd, 1H, H-1, J = 13.7, 3.8, 3.87 Hz), 2.34 (s, 1H,
H-9), 2.06 (dd, 1H, H-18, J = 13.3, 3.37 Hz), 2.00 (m, 1H, H-15),
1.97 (m, 1H, H-21), 1.90 (m, 1H, H-19), 1.80 (ddd, 1H, H-16,
J = 13.8, 13.8, 4.57 Hz), 1.70 (m, 1H, H-2), 1.63 (m, 1H,
H-7), 1.59 (m, 1H, H-20), 1.59 (dd, 1H, H-190, J = 13.6, 13.67 Hz),
1.56 (m, 1H, H-6), 1.44 (m, 1H, H-60), 1.39 (m, 1H, H-70), 1.36 (m,
1H, H-22), 1.34 (s, 3H, H-27), 1.32 (d, 3H, Ala-CH3, J = 7.07 Hz),
1.29 (m, 2H, H-220 and H-210), 1.16 (m, 1H, H-160), 1.14 (s, 3H,
H-25), 1.12 (s, 3H, H-28), 1.10 (s, 3H, H-26), 1.04 (ddd, 1H, H-10,
J = 13.5, 13.5, 4.17 Hz), 0.99 (m, 1H, H-150), 0.87 (s, 3H, H-23),
686 (w), 545 (w) cmꢃ1 1H NMR (400 MHz, CDCl3): d = 5.60 (s,
;
1H, H-12), 5.01 (qq, 1H, i-Pr-CH, J = 6.4, 6.47 Hz), 4.51 (dd, 1H,
H-3, J = 11.7, 4.57 Hz), 3.53 (q, 1H, Ala-CH, J = 7.17 Hz), 2.79 (ddd,
1H, H-1, J = 13.6, 3.5, 3.57 Hz), 2.34 (s, 1H, H-9), 2.08 (dd, 1H,
H-18, J = 13.2, 3.37 Hz), 2.01 (dd, 1H, H-15, J = 13.7, 4.67 Hz), 1.96
(m, 1H, H-21), 1.89 (m, 1H, H-19), 1.80 (ddd, 1H, H-16, J = 13.6,
13.6, 4.57 Hz), 1.71 (m, 1H, H-2), 1.64 (m, 1H, H-7), 1.60 (m, 1H,
H-20), 1.58 (dd, 1H, H-190, J = 13.2, 13.27 Hz), 1.56 (m, 1H, H-6),
1.44 (m, 1H, H-60), 1.41 (m, 1H, H-70), 1.36 (m, 1H, H-22), 1.34 (s,
3H, H-27), 1.32 (d, 3H, Ala-CH3, J = 7.07 Hz), 1.31 (m, 1H, H-220),
1.30 (m, 1H, H-210), 1.23 (d, 3H, i-Pr-CH3, J = 6.27 Hz), 1.20 (d, 3H,

S. Schwarz, R. Csuk / Bioorg. Med. Chem. 18 (2010) 7458–7474
7469
i-Pr-CH3, J = 6.27 Hz), 1.18 (m, 1H, H-160), 1.14 (s, 3H, H-25), 1.10
(s, 6H, H-28 and H-26), 1.04 (ddd, 1H, H-10, J = 13.1, 13.1,
3.27 Hz), 0.99 (m, 1H, H-150), 0.87 (s, 3H, H-23), 0.86 (s, 3H, H-
24), 0.79 (m, 1H, H-5), 0.77 (s, 3H, H-29); 13C NMR (125 MHz,
CDCl3): d = 200.0 (C-11), 176.2 (C-30), 175.8 (Ala-COO), 169.5
(C-13), 128.4 (C-12), 81.1 (C-3), 67.3 (i-Pr-CH), 61.7 (C-9), 55.0
(C-5), 50.2 (Ala-CH), 48.4 (C-18), 45.4 (C-8), 43.7 (C-20), 43.2
(C-14), 41.0 (C-19), 38.7 (C-1), 38.1 (C-4), 37.7 (C-22), 36.9
(C-10), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21), 28.6 (C-29), 28.2
(C-23), 28.1 (C-28), 26.5 (C-16), 26.4 (C-15), 23.4 (C-2), 23.3
(C-27), 21.9 (i-Pr-CH3), 21.7 (i-Pr-CH3), 20.7 (Ala-CH3), 18.7
(C-26), 17.3 (C-6), 16.7 (C-24), 16.4 (C-25). Anal. Calcd for
1.42 (s, 9H, Boc-CH3), 1.40 (m, 1H, H-70), 1.38 (d, 3H, Ala-CH3,
J = 7.17 Hz), 1.36 (m, 1H, H-22), 1.35 (s, 3H, H-27), 1.33 (m, 2H,
H-220 and H-210), 1.21 (s, 3H, H-28), 1.17 (m, 1H, H-160), 1.15
(s, 3H, H-25), 1.11 (s, 3H, H-26), 1.03 (m, 1H, H-10), 1.01 (m, 1H,
H-150), 0.87 (s, 3H, H-24), 0.85 (s, 3H, H-23), 0.82 (s, 3H, H-29),
0.79 (m, 1H, H-5); 13C NMR (125 MHz, CDCl3): d = 200.2 (C-11),
181.0 (C-30), 173.0 (Ala-COO), 169.4 (C-13), 155.0 (Boc-COO),
128.4 (C-12), 81.7 (C-3), 77.9 (Boc-quart.-C), 61.6 (C-9), 55.0
(C-5), 49.5 (Ala-CH), 48.2 (C-18), 45.4 (C-8), 43.7 (C-20), 43.2
(C-14), 40.9 (C-19), 38.7 (C-1), 38.2 (C-4), 37.7 (C-22), 36.9
(C-10), 32.7 (C-7), 31.8 (C-17), 30.9 (C-21), 28.5 (C-29), 28.4
(C-23), 28.3 (Boc-CH3), 28.0 (C-28), 26.5 (C-16), 26.4 (C-15), 23.5
(C-2), 23.3 (C-27), 18.9 (Ala-CH3), 18.7 (C-26), 17.3 (C-6), 16.7
(C-24), 16.4 (C-25). Anal. Calcd for C38H59NO7 (641.88): C, 71.10;
H, 9.26; N, 2.18. Found: C, 71.00; H, 9.31; N, 2.12.
C36H57NO5 (583.84): C, 74.06; H, 9.84; N, 2.40. Found: C, 73.99;
H, 9.95; N, 2.35.
4.2.6.26.
3b-(Boc-glycyl)-11-oxo-olean-12-en-30-oic
acid
(26). Obtained from 38 by method C as a colourless powder;
4.2.6.28.
3b-(Boc-b-alanyl)-11-oxo-olean-12-en-30-oic
acid
yield: 320 mg, 58%; mp 288–290 °C (decomp.); Rf = 0.14 (hexane/
(28). Obtained from 40 by method C as a colourless powder;
yield: 190 mg, 52%; mp 227–231 °C (decomp.); Rf = 0.09 (hexane/
ethyl acetate 7:3); ½a D20
ꢂ
= 115.49 (c 0.43, CHCl3); UV–vis (MeOH):
kmax (log
e
) = 250 nm (4.06); MS (ESI): m/z (%) = 650.4 ([M+Na]+,
ethyl acetate 7:3); ½a D20
ꢂ
= 113.35 (c 0.21, CHCl3); UV–vis (MeOH):
100), 964.2 ([3M+2Na]2+, 14), 1278.1 ([2M+Na]+, 18); IR (KBr):
= 3295 (br), 2973 (s), 2874 (m), 1752 (s), 1719 (s), 1651 (s),
kmax (log e
) = 250 nm (4.08); MS (ESI): m/z (%) = 664.4 ([M+Na]+,
m
100), 985.3 ([3M+2Na]2+, 8), 1305.1 ([2M+Na]+, 20); IR (KBr):
m = 3356 (br), 2968 (s), 1739 (s), 1703 (s), 1653 (s), 1528 (m),
1514 (m), 1456 (m), 1390 (s), 1368 (s), 1281 (m), 1258 (m), 1217
(s), 1164 (s), 1088 (w), 1051 (m), 1028 (m), 984 (m), 948 (w),
916 (w), 883 (w), 867 (w), 777 (w), 754 (w), 700 (w), 671 (w),
1452 (m), 1390 (m), 1368 (m), 1326 (m), 1302 (m), 1257 (m),
1210 (m), 1179 (s), 1072 (w), 1022 (w), 984 (w), 915 (m), 880
590 (w), 558 (w), 442 (w) cmꢃ1
;
1H NMR (400 MHz, CDCl3):
(w), 860 (w), 754 (w), 542 (w) cmꢃ1 1H NMR (400 MHz, CDCl3):
;
d = 5.68 (s, 1H, H-12), 4.98 (m, 1H, Gly-NH), 4.57 (dd, 1H, H-3,
J = 11.6, 4.87 Hz), 3.88 (m, 2H, Gly-CH2), 2.79 (ddd, 1H, H-1,
J = 13.7, 3.3, 3.37 Hz), 2.34 (s, 1H, H-9), 2.17 (dd, 1H, H-18,
J = 12.9, 4.27 Hz), 2.01 (ddd, 1H, H-15, J = 13.3, 13.3, 4.27 Hz),
1.98 (m, 1H, H-21), 1.91 (m, 1H, H-19), 1.81 (ddd, 1H, H-16,
J = 13.3, 13.3, 3.77 Hz), 1.72 (m, 1H, H-2), 1.68 (m, 1H, H-7), 1.63
(m, 1H, H-20), 1.61 (dd, 1H, H-190, J = 13.7, 13.77 Hz), 1.57 (m, 1H,
H-6), 1.43 (s, 9H, Boc-CH3), 1.42 (m, 1H, H-60), 1.39 (m, 1H, H-70),
1.38 (m, 1H, H-22), 1.37 (s, 3H, H-27), 1.36 (m, 1H, H-220), 1.32
(m, 1H, H-210), 1.20 (s, 3H, H-28), 1.19 (m, 1H, H-160), 1.14 (s,
3H, H-25), 1.11 (s, 3H, H-26), 1.03 (m, 1H, H-10), 1.01 (m, 1H,
H-150), 0.86 (s, 6H, H-23 and H-24), 0.81 (s, 3H, H-29), 0.78
(m, 1H, H-5); 13C NMR (125 MHz, CDCl3): d = 200.1 (C-11), 180.6
(C-30), 170.1 (Gly-COO), 169.4 (C-13), 155.6 (Boc-COO), 128.5
(C-12), 82.0 (C-3), 77.3 (Boc-quart.-C), 61.7 (C-9), 55.0 (C-5), 48.2
(C-18), 45.4 (C-8), 43.7 (C-20), 43.2 (C-14), 42.7 (Gly-CH2), 40.9
(C-19), 38.7 (C-1), 38.1 (C-4), 37.7 (C-22), 36.9 (C-10), 32.7 (C-7),
31.9 (C-17), 31.0 (C-21), 28.5 (C-29), 28.4 (C-23), 28.3 (Boc-CH3),
28.1 (C-28), 26.5 (C-16), 26.4 (C-15), 23.5 (C-2), 23.4 (C-27), 18.7
(C-26), 17.4 (C-6), 16.6 (C-24), 16.4 (C-25). Anal. Calcd for
d = 5.69 (s, 1H, H-12), 4.96 (m, 1H, Ala-NH), 4.52 (dd, 1H, H-3,
J = 11.7, 4.67 Hz), 3.37 (dt, 2H, Ala-CH2NH2, J = 5.8, 5.87 Hz), 2.79
(ddd, 1H, H-1, J = 13.8, 3.3, 3.37 Hz), 2.51 (m, 2H, Ala-CH2COO),
2.35 (s, 1H, H-9), 2.17 (dd, 1H, H-18, J = 12.8, 3.77 Hz), 2.01 (m,
1H, H-15), 1.98 (m, 1H, H-21), 1.92 (ddd, 1H, H-19, J = 13.8, 4.1,
2.47 Hz), 1.82 (m, 1H, H-16), 1.71 (m, 1H, H-2), 1.66 (m, 1H,
H-7), 1.63 (m, 1H, H-20), 1.61 (dd, 1H, H-190, J = 13.2, 13.27 Hz),
1.57 (m, 1H, H-6), 1.45 (m, 1H, H-60), 1.42 (s, 9H, Boc-CH3), 1.41
(m, 1H, H-70), 1.39 (m, 1H, H-22), 1.35 (s, 3H, H-27), 1.33 (m, 1H,
H-220), 1.31 (m, 1H, H-210), 1.21 (s, 3H, H-28), 1.20 (m, 1H, H-
160), 1.15 (s, 3H, H-25), 1.11 (s, 3H, H-26), 1.03 (m, 1H, H-10),
1.01 (m, 1H, H-150), 0.86 (s, 3H, H-24), 0.85 (s, 3H, H-23), 0.82 (s,
3H, H-29), 0.78 (m, 1H, H-5); 13C NMR (125 MHz, CDCl3):
d = 200.2 (C-11), 180.6 (C-30), 172.1 (Ala-COO), 169.3 (C-13),
155.6 (Boc-COO), 128.5 (C-12), 81.1 (C-3), 77.3 (Boc-quart.-C),
61.7 (C-9), 55.0 (C-5), 48.2 (C-18), 45.4 (C-8), 43.7 (C-20), 43.2
(C-14), 40.9 (C-19), 38.8 (C-1), 38.1 (C-4), 37.7 (C-22), 36.9
(C-10), 36.4 (Ala-CH2NH2), 34.7 (Ala-CH2COO), 32.7 (C-7), 31.9
(C-17), 31.0 (C-21), 28.5 (C-29), 28.4 (C-23 and Boc-CH3), 28.1
(C-28), 26.5 (C-16), 26.5 (C-15), 23.6 (C-2), 23.4 (C-27), 18.7
(C-26), 17.4 (C-6), 16.7 (C-24), 16.4 (C-25). Anal. Calcd for
C37H57NO7 (627.85): C, 70.78; H, 9.15; N, 2.23. Found: C, 70.75;
H, 9.25; N, 2.12.
C38H59NO7 (641.88): C, 71.10; H, 9.26; N, 2.18. Found: C, 71.02;
H, 9.33; N, 2.05.
4.2.6.27.
3b-(Boc-L-alanyl)-11-oxo-olean-12-en-30-oic acid
(27). Obtained from 39 by method C as a colourless powder;
yield: 220 mg, 66%; mp 231–234 °C (decomp.); Rf = 0.71 (hexane/
4.2.6.29. Methyl 3b-(Boc-glycyl)-11-oxo-olean-12-en-30-oate
(29). Obtained from 1 and Boc-Gly by method A as a colourless
powder; yield: 450 mg, 96%; mp 251–254 °C (decomp.); Rf = 0.58
ethyl acetate 7:3); ½a D20
ꢂ
= 95.89 (c 0.45, CHCl3); UV–vis (MeOH):
kmax (log
e
) = 250 nm (4.81); MS (ESI): m/z (%) = 642.2 ([M+H]+,
(hexane/ethyl acetate 7:3); ½a D20
ꢂ
= 92.72 (c 0.29, MeOH); UV–vis
(MeOH): kmax (log e) = 249 nm (4.03); MS (ESI): m/z (%) = 641.9
4), 664.4 ([M+Na]+, 100), 985.3 ([3M+2Na]+, 22); IR (KBr):
= 3383 (br), 2976 (s), 2876 (m), 1719 (s), 1661 (s), 1499 (m),
m
([M+H]+, 12), 659.0 ([M+NH4]+, 12), 664.3 ([M+Na]+, 100); IR
(KBr): = 3397 (br), 2969 (s), 2874 (m), 1754 (s), 1724 (s), 1651
1455 (s), 1390 (s), 1368 (s), 1306 (m), 1259 (m), 1214 (s), 1167
(s), 1087 (m), 1066 (m), 1023 (m), 973 (m), 916 (w), 881 (w),
865 (w), 754 (w), 699 (s), 668 (w), 588 (w), 541 (w), 464 (w)
m
(s), 1522 (s), 1464 (m), 1390 (s), 1366 (s), 1348 (m), 1319 (m),
1248 (m), 1215 (s), 1164 (s), 1106 (m), 1087 (m), 1053 (m), 1024
(m), 985 (m), 948 (w), 916 (w), 881 (w), 868 (w), 825 (w), 756
cmꢃ1 1H NMR (400 MHz, CDCl3): d = 5.69 (s, 1H, H-12), 5.06 (m,
;
1H, Ala-NH), 4.55 (dd, 1H, H-3, J = 11.6, 4.67 Hz), 4.28 (m, 1H,
Ala-CH), 2.80 (ddd, 1H, H-1, J = 13.7, 3.4, 3.47 Hz), 2.35 (s, 1H,
H-9), 2.17 (dd, 1H, H-18, J = 13.3, 3.37 Hz), 2.02 (m, 1H, H-15),
1.98 (m, 1H, H-21), 1.92 (m, 1H, H-19), 1.82 (m, 1H, H-16), 1.71
(m, 1H, H-2), 1.65 (m, 1H, H-7), 1.62 (m, 1H, H-20), 1.61 (dd, 1H,
H-190, J = 13.4, 13.47 Hz), 1.57 (m, 1H, H-6), 1.43 (m, 1H, H-60),
(s), 686 (w), 667 (w), 590 (w), 551 (w), 537 (w) cmꢃ1 1H NMR
;
(400 MHz, CDCl3): d = 5.63 (s, 1H, H-12), 4.98 (m, 1H, Gly-NH),
4.56 (dd, 1H, H-3, J = 11.6, 5.07 Hz), 3.87 (d, 2H, Gly-CH2,
J = 5.07 Hz), 3.66 (s, 3H, OMe), 2.79 (ddd, 1H, H-1, J = 13.7, 3.6,
3.67 Hz), 2.33 (s, 1H, H-9), 2.05 (m, 1H, H-18), 2.00 (m, 1H,
H-15), 1.96 (m, 1H, H-21), 1.90 (ddd, 1H, H-19, J = 13.7, 3.7,

7470
S. Schwarz, R. Csuk / Bioorg. Med. Chem. 18 (2010) 7458–7474
2.57 Hz), 1.80 (ddd, 1H, H-16, J = 13.7, 13.7, 4.77 Hz), 1.72 (m, 1H,
H-2), 1.66 (m, 1H, H-7), 1.63 (m, 1H, H-20), 1.58 (dd, 1H, H-190,
J = 13.7, 13.77 Hz), 1.56 (m, 1H, H-6), 1.43 (m, 1H, H-60), 1.42 (s,
9H, Boc-CH3), 1.39 (m, 1H, H-70), 1.37 (m, 1H, H-22), 1.33 (s, 3H,
H-27), 1.32 (m, 1H, H-220), 1.28 (m, 1H, H-210), 1.16 (m, 1H, H-
160), 1.13 (s, 3H, H-25), 1.12 (s, 3H, H-26), 1.10 (s, 3H, H-28),
1.02 (ddd, 1H, H-10, J = 13.3, 13.3, 3.77 Hz), 0.99 (m, 1H, H-150),
0.85 (s, 6H, H-23 and H-24), 0.78 (s, 3H, H-29), 0.77 (m, 1H, H-
5); 13C NMR (125 MHz, CDCl3): d = 199.9 (C-11), 176.9 (C-30),
170.1 (Gly-COO), 169.2 (C-13), 155.6 (Boc-COO), 128.5 (C-12),
81.9 (C-3), 77.8 (Boc-quart.-C), 61.6 (C-9), 55.0 (C-5), 51.7 (OMe),
48.4 (C-18), 45.4 (C-8), 44.0 (C-20), 43.2 (C-14), 42.6 (Gly-CH2),
41.1 (C-19), 38.7 (C-1), 38.1 (C-4), 37.7 (C-22), 36.9 (C-10), 32.6
(C-7), 31.8 (C-17), 31.1 (C-21), 28.5 (C-29), 28.3 (C-23 and
Boc-CH3), 28.0 (C-28), 26.4 (C-16), 26.4 (C-15), 23.5 (C-2), 23.3
(C-27), 18.6 (C-26), 17.3 (C-6), 16.6 (C-24), 16.4 (C-25). Anal. Calcd
for C38H59NO7 (641.88): C, 71.10; H, 9.26; N, 2.18. Found: C, 71.08;
H, 9.35; N, 2.11.
H-1, J = 13.7, 3.7, 3.77 Hz), 2.51 (m, 2H, Ala-CH2COO), 2.34 (s, 1H,
H-9), 2.06 (m, 1H, H-18), 2.01 (m, 1H, H-15), 1.97 (m, 1H, H-21),
1.91 (m, 1H, H-19), 1.81 (ddd, 1H, H-16, J = 13.2, 13.2, 4.27 Hz),
1.71 (m, 1H, H-2), 1.66 (m, 1H, H-7), 1.62 (m, 1H, H-20), 1.59 (dd,
1H, H-190, J = 13.3, 13.37 Hz), 1.56 (m, 1H, H-6), 1.44 (m, 1H,
H-60), 1.41 (s, 9H, Boc-CH3), 1.40 (m, 1H, H-70), 1.38 (m, 1H,
H-22), 1.35 (s, 3H, H-27), 1.31 (m, 1H, H-220), 1.28 (m, 1H,
H-210), 1.16 (m, 1H, H-160), 1.14 (s, 3H, H-25), 1.13 (s, 3H, H-26),
1.11 (s, 3H, H-28), 1.03 (m, 1H, H-10), 0.99 (m, 1H, H-150), 0.86 (s,
3H, H-24), 0.85 (s, 3H, H-23), 0.79 (s, 3H, H-29), 0.78 (m, 1H,
H-5); 13C NMR (125 MHz, CDCl3): d = 200.0 (C-11), 176.9 (C-30),
172.3 (Ala-COO), 169.2 (C-13), 156.3 (Boc-COO), 128.5 (C-12),
81.1 (C-3), 79.6 (Boc-quart.-C), 61.7 (C-9), 55.0 (C-5), 51.8 (OMe),
48.4 (C-18), 45.4 (C-8), 44.0 (C-20), 43.2 (C-14), 41.1 (C-19), 38.8
(C-1), 38.1 (C-4), 37.7 (C-22), 36.9 (C-10), 36.4 (Ala-CH2NH2),
34.7 (Ala-CH2COO), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21), 28.5
(C-29), 28.4 (Boc-CH3), 28.3 (C-28), 28.1 (C-23), 26.4 (C-16), 26.4
(C-15), 23.6 (C-2), 23.3 (C-27), 18.7 (C-26), 17.4 (C-6), 16.7
(C-24), 16.4 (C-25). Anal. Calcd for C39H61NO7 (655.90): C, 71.42;
H, 9.37; N, 2.14. Found: C, 71.19; H, 9.52; N, 1.99.
4.2.6.30. Methyl 3b-(Boc-L-alanyl)-11-oxo-olean-12-en-30-oate
(30). Obtained from 1 and Boc-L-Ala by method A as a colourless
powder; yield: 400 mg, 72%; mp 249–252 °C (decomp.); Rf = 0.68
4.2.6.32. Ethyl 3b-(Boc-L-glycyl)-11-oxo-olean-12-en-30-oate
(32). Obtained from 2 and Boc-Gly by method A as a colourless
(hexane/ethyl acetate 7:3); ½a D20
ꢂ
= 98.76 (c 0.43, CHCl3); UV–vis
(MeOH): kmax (log e) = 249 nm (4.08); MS (ESI): m/z (%) = 655.9
powder; yield: 372 mg, 71%; mp 227–229 °C (decomp.); Rf = 0.56
([M+H]+, 14), 673.1 (M+NH4, 16), 678.3 ([M+Na]+, 100); IR (KBr):
= 3393 (br), 2972 (s), 2931 (s), 2874 (m), 1746 (s), 1722 (s),
(hexane/ethyl acetate 7:3); ½a D20
ꢂ
= 108.70 (c 0.40, CHCl3); UV–vis
m
(MeOH): kmax (log e) = 249 nm (4.10); MS (ESI): m/z (%) = 656.3
1706 (s), 1652 (s), 1514 (s), 1455 (s), 1390 (m), 1365 (m), 1336
(s), 1280 (w), 1248 (m), 1216 (s), 1165 (s), 1094 (m), 1052 (s),
1029 (m), 985 (m), 970 (m), 917 (w), 882 (w), 866 (w), 850 (w),
827 (w), 780 (w), 772 (w), 686 (w), 670 (w), 590 (w), 538 (w)
([M+H]+, 7), 667.3 ([2M+H+Na]2+
1006.5 ([3M+2Na]2+ 34), 1333.8 ([2M+Na]+, 60); IR (KBr):
= 3407 (br), 2978 (s), 1724 (s), 1659 (s), 1508 (w), 1456 (m),
1390 (m), 1366 (m), 1249 (m), 1215 (s), 1172 (s), 1086 (w), 1053
(w), 1022 (w), 985 (w), 867 (w), 769 (w) cmꢃ1 1H NMR
,
19), 678.4 ([M+Na]+, 100),
,
m
cmꢃ1
;
1H NMR (400 MHz, CDCl3): d = 5.64 (s, 1H, H-12), 5.04 (m,
;
1H, Ala-NH), 4.54 (dd, 1H, H-3, J = 11.6, 4.67 Hz), 4.28 (m, 1H,
Ala-CH), 3.66 (s, 3H, OMe), 2.80 (ddd, 1H, H-1, J = 13.5, 3.4,
3.47 Hz), 2.34 (s, 1H, H-9), 2.06 (dd, 1H, H-18, J = 13.7, 3.77 Hz),
2.00 (m, 1H, H-15), 1.97 (m, 1H, H-21), 1.90 (ddd, 1H, H-19,
J = 13.7, 3.7, 2.47 Hz), 1.80 (ddd, 1H, H-16, J = 13.8, 13.8, 4.77 Hz),
1.72 (m, 1H, H-2), 1.63 (m, 1H, H-7), 1.60 (m, 1H, H-20), 1.59 (dd,
1H, H-190, J = 13.4, 13.47 Hz), 1.56 (m, 1H, H-6), 1.44 (m, 1H,
H-60), 1.42 (s, 9H, Boc-CH3), 1.41 (m, 1H, H-70), 1.38 (d, 3H, Ala-
CH3, J = 7.27 Hz), 1.37 (m, 1H, H-22), 1.34 (s, 3H, H-27), 1.29 (m,
2H, H-220 and H-210), 1.16 (m, 1H, H-160), 1.14 (s, 3H, H-25), 1.13
(s, 3H, H-28), 1.10 (s, 3H, H-26), 1.03 (ddd, 1H, H-10, J = 13.7,
13.7, 3.87 Hz), 0.99 (m, 1H, H-150), 0.87 (s, 3H, H-23), 0.85 (s, 3H,
H-24), 0.79 (m, 1H, H-5), 0.78 (s, 3H, H-29); 13C NMR (125 MHz,
CDCl3): d = 200.0 (C-11), 176.9 (C-30), 173.0 (Ala-COO), 169.2
(C-13), 155.0 (Boc-COO), 128.5 (C-12), 81.7 (C-3), 79.6 (Boc-
quart.-C), 61.7 (C-9), 55.0 (C-5), 51.7 (OMe), 49.5 (Ala-CH), 48.4
(C-18), 45.4 (C-8), 44.0 (C-20), 43.2 (C-14), 41.1 (C-19), 38.7
(C-1), 38.2 (C-4), 37.7 (C-22), 36.9 (C-10), 32.7 (C-7), 31.8 (C-17),
31.1 (C-21), 28.5 (C-29), 28.3 (Boc-CH3), 28.3 (C-23), 28.0 (C-28),
26.4 (C-16), 26.4 (C-15), 23.5 (C-2), 23.3 (C-27), 18.9 (Ala-CH3),
18.7 (C-26), 17.3 (C-6), 16.7 (C-24), 16.4 (C-25). Anal. Calcd for
(500 MHz, CDCl3): d = 5.64 (s, 1H, H-12), 4.99 (t, 1H, Gly-NH,
J = 4.97 Hz), 4.58 (dd, 1H, H-3, J = 11.7, 4.8 7 Hz), 4.18 (dq, 1H,
COOCHH0, J = 10.7, 7.27 Hz), 4.12 (dq, 1H, COOCHH0, J = 10.7,
7.27 Hz), 3.89 (d, 2H, Gly-CH2NH, J = 4.97 Hz), 2.81 (ddd, 1H, H-1,
J = 13.7, 3.7, 3.77 Hz), 2.35 (s, 1H, H-9), 2.09 (dd, 1H, H-18,
J = 13.3, 3.37 Hz), 2.02 (ddd, 1H, H-16, J = 13.6, 13.6, 4.57 Hz),
1.98 (m, 1H, H-21), 1.92 (ddd, 1H, H-19, J = 13.7, 4.0, 2.67 Hz),
1.82 (ddd, 1H, H-16, J = 13.7, 13.7, 4.57 Hz), 1.72 (m, 1H, H-2),
1.65 (m, 1H, H-7), 1.63 (m, 1H, H-20), 1.60 (dd, 1H, H-190, J = 1.34,
13.47 Hz), 1.58 (m, 1H, H-6), 1.45 (m, 1H, H-60), 1.44 (s, 9H, Boc-
CH3), 1.42 (m, 1H, H-70), 1.38 (m, 1H, H-22), 1.35 (s, 3H, H-27),
1.32 (m, 1H, H-220), 1.30 (m, 1H, H-210), 1.25 (t, 3H, COOCH2CH3,
J = 7.27 Hz), 1.17 (m, 1H, H-160), 1.15 (s, 3H, H-25), 1.13 (s, 3H,
H-28), 1.12 (s, 3H, H-26), 1.04 (ddd, 1H, H-10, J = 13.6, 13.6,
3.47 Hz), 1.01 (m, 1H, H-150), 0.87 (s, 6H, H-23 and H-24), 0.79
(s, 3H, H-29), 0.79 (m, 1H, H-5); 13C NMR (125 MHz, CDCl3):
d = 200.0 (C-11), 176.3 (C-30), 170.1 (Gly-COO), 169.4 (C-13),
156.2 (Boc-COO), 128.4 (C-12), 82.0 (C-3), 79.7 (Boc-quart.-C),
61.7 (C-9), 60.3 (COOCH2), 55.0 (C-5), 48.4 (C-18), 45.4 (C-8),
43.8 (C-20), 43.2 (C-14), 42.6 (Gly-CNH), 41.0 (C-19), 38.7 (C-1),
38.1 (C-10), 37.7 (C-22), 36.9 (C-4), 32.7 (C-7), 31.8 (C-17), 31.1
(C-21), 28.5 (C-29), 28.3 (3ꢁ Boc-CH3 and C-23), 28.0 (C-28), 26.5
(C-16), 26.4 (C-15), 23.5 (C-2), 23.3 (C-27), 18.6 (C-26), 17.3
(C-6), 16.6 (C-24), 16.4 (C-25), 14.3 (COOCH2CH3). Anal. Calcd for
C39H61NO7 (655.90): C, 71.42; H, 9.37; N, 2.14. Found: C, 71.18;
H, 9.42; N, 2.08.
4.2.6.31. Methyl 3b-(Boc-b-alanyl)-11-oxo-olean-12-en-30-oate
(31). Obtained from 1 and Boc-b-Ala by method A as a colourless
powder; yield: 460 mg, 88%; mp 188–191 °C (decomp.); Rf = 0.58
C39H61NO7 (655.90): C, 71.42; H, 9.37; N, 2.14. Found: C, 71.27;
H, 9.52; N, 2.05.
(hexane/ethyl acetate 7:3); ½a D20
ꢂ
= 105.52 (c 0.28, CHCl3); UV–vis
) = 249 nm (4.08); MS (ESI): m/z (%) = 656.2
4.2.6.33. Ethyl 3b-(Boc-L-alanyl)-11-oxo-olean-12-en-30-oate
(MeOH): kmax (log
e
(33). Obtained from 2 and Boc-L-Ala by method A as a colourless
([M+H]+, 15), 678.3 ([M+Na]+, 100); IR (KBr):
m
= 3406 (br), 2973
powder; yield: 589 mg, 95%; mp 202–205 °C (decomp.); Rf = 0.66
(s), 1731 (s), 1660 (m), 1508 (m), 1456 (m), 1390 (m), 1366 (m),
1249 (m), 1216 (m), 1170 (s), 1086 (w), 986 (w), 880 (w), 755
(hexane/ethyl acetate 7:3); ½a D20
ꢂ
= 99.75 (c 0.61, CHCl3); UV–vis
(MeOH): kmax (log e) = 249 nm (4.09); MS (ESI): m/z (%) = 670.3
(w) cmꢃ1
;
1H NMR (500 MHz, CDCl3): d = 5.65 (s, 1H, H-12), 4.94
([M+H]+, 23), 629.4 ([M+Na]+, 100), 1027.3 ([3M+2Na]2+, 28),
1339.2 ([2M+H]+, 22), 1362.2 ([2M+Na]+, 26); IR (KBr):
= 3397
(br), 2972 (s), 2874 (m), 1746 (s), 1720 (s), 1652 (s), 1512 (m),
(m, 1H, Ala-NH), 4.52 (dd, 1H, H-3, J = 11.7, 4.77 Hz), 3.67 (s, 3H,
OMe), 3.37 (dt, 2H, Ala-CH2NH2, J = 5.8, 5.87 Hz), 2.79 (ddd, 1H,
m

S. Schwarz, R. Csuk / Bioorg. Med. Chem. 18 (2010) 7458–7474
7471
1456 (m), 1390 (m), 1367 (m), 1336 (m), 1280 (w), 1248 (w), 1216
(s), 1169 (s), 1087 (w), 1051 (m), 1029 (m), 984 (w), 970 (w), 917
(w), 881 (w), 865 (w), 770 (w), 670 (w), 589 (w), 538 (w) cmꢃ1; 1H
NMR (500 MHz, CDCl3): d = 5.63 (s, 1H, H-12), 5.06 (d, 1H, Ala-NH),
4.55 (dd, 1H, H-3, J = 11.9, 4.77 Hz), 4.29 (m, 1H, Ala-CHNH), 4.17
(dq, 1H, COOCHH0, J = 10.8, 7.27 Hz), 4.11 (dq, 1H, COOCHH0,
J = 10.8, 7.27 Hz), 2.81 (ddd, 1H, H-1, J = 13.7, 3.5, 3.57 Hz), 2.35
(s, 1H, H-9), 2.09 (dd, 1H, H-18, J = 13.1, 3.77 Hz), 2.02 (ddd, 1H,
H-15, J = 13.4, 13.4, 4.67 Hz), 1.98 (m, 1H, H-21), 1.91 (ddd, 1H,
H-19, J = 13.6, 4.1, 2.77 Hz), 1.81 (ddd, 1H, H-16, J = 13.4, 13.4,
4.77 Hz), 1.72 (m, 1H, H-2), 1.61 (m, 1H, H-20), 1.60 (dd, 1H, H-
190, J = 13.6, 13.67 Hz), 1.45 (m, 1H, H-7), 1.43 (s, 9H, Boc-CH3),
1.41 (m, 1H, H-70), 1.40 (m, 1H, H-22), 1.39 (d, 3H, Ala-CH3,
J = 7.27 Hz), 1.38 (m, 1H, H-6), 1.37 (m, 1H, H-60), 1.35 (s, 3H, H-
27), 1.34 (m, 1H, H-220), 1.30 (m, 1H, H-210), 1.25 (t, 3H,
COOCH2CH3, J = 7.27 Hz), 1.17 (m, 1H, H-160), 1.15 (s, 3H, H-25),
1.13 (s, 3H, H-28), 1.11 (s, 3H, H-26), 1.04 (ddd, 1H, H-10, J = 13.7,
13.7, 3.47 Hz), 1.00 (m, 1H, H-150), 0.88 (s, 3H, H-24), 0.86 (s, 3H,
H-23), 0.80 (m, 1H, H-5), 0.79 (s, 3H, H-29); 13C NMR (125 MHz,
CDCl3): d = 199.9 (C-11), 176.3 (C-30), 173.0 (Ala-COO), 169.3
(C-13), 155.0 (Boc-COO), 128.4 (C-12), 81.7 (C-3), 79.6 (Boc-
quart.-C), 61.7 (C-9), 60.3 (COOCH2), 55.0 (C-5), 49.5 (Ala-CNH),
48.4 (C-18), 45.4 (C-8), 43.8 (C-20), 43.2 (C-14), 41.0 (C-19), 38.7
(C-1), 38.2 (C-4), 37.7 (C-22), 36.9 (C-10), 32.7 (C-7), 31.8 (C-17),
31.1 (C-21), 28.5 (C-29), 28.3 (3ꢁ Boc-CH3), 28.2 (C-28), 28.0
(C-23), 26.5 (C-16), 26.4 (C-15), 23.5 (C-2), 23.3 (C-27), 18.9
(Ala-CH3), 18.6 (C-26), 17.3 (C-6), 16.7 (C-24), 16.3 (C-25), 14.3
(COOCH2CH3). Anal. Calcd for C40H63NO7 (669.93): C, 71.71; H,
9.48; N, 2.09. Found: C, 71.51; H, 9.53; N, 1.87.
4.2.6.35. i-Propyl 3b-(Boc-b-glycyl)-11-oxo-olean-12-en-30-oate
(35). Obtained from 3 and Boc-Gly by method A as a colourless
powder; yield: 410 mg, 96%; mp 220–222 °C (decomp.); Rf = 0.69
(hexane/ethyl acetate 7:3); ½a D20
ꢂ
= 90.23 (c 0.50, CHCl3); UV–vis
(MeOH): kmax (log e) = 250 nm (4.07); MS (ESI): m/z (%) = 692.3
([M+Na]+, 100), 1027.3 ([3M+2Na]2+, 14), 1361.2 ([2M+Na]+, 12);
IR (KBr): = 3405 (br), 2978 (s), 2875 (m), 1723 (s), 1661 (s),
m
1509 (m), 1456 (m), 1388 (m), 1367 (m), 1281 (m), 1250 (m),
1216 (s), 1172 (s), 1108 (m), 1086 (w), 1054 (w), 1028 (w), 985
(m), 948 (w), 916 (w), 866 (w), 770 (w), 588 (w) cmꢃ1 1H NMR
;
(400 MHz, CDCl3): d = 5.61 (s, 1H, H-12), 5.02 (qq, 1H, i-Pr-CH,
J = 6.2, 6.27 Hz), 4.98 (m, 1H, Gly-NH), 4.56 (dd, 1H, H-3, J = 11.5,
4.47 Hz), 3.88 (d, 2H, Gly-CH2, J = 4.97 Hz), 2.79 (ddd, 1H, H-1,
J = 13.7, 3.6, 3.67 Hz), 2.34 (s, 1H, H-9), 2.09 (dd, 1H, H-18,
J = 13.3, 3.37 Hz), 2.01 (ddd, 1H, H-15, J = 13.3, 5.0, 5.07 Hz), 1.96
(m, 1H, H-21), 1.89 (ddd, 1H, H-19), 1.80 (ddd, 1H, H-16, J = 13.7,
13.7, 4.27 Hz), 1.73 (m, 1H, H-2), 1.64 (m, 1H, H-7), 1.60 (m, 1H,
H-20), 1.58 (dd, 1H, H-190, J = 13.5, 13.57 Hz), 1.57 (m, 1H, H-6),
1.44 (m, 1H, H-60), 1.43 (s, 9H, Boc-CH3), 1.41 (m, 1H, H-70), 1.36
(m, 1H, H-22), 1.34 (s, 3H, H-27), 1.32 (m, 1H, H-220), 1.26 (m,
1H, H-210), 1.23 (d, 3H, i-Pr-CH3, J = 6.27 Hz), 1.20 (d, 3H, i-Pr-
CH3, J = 6.27 Hz), 1.16 (m, 1H, H-160), 1.14 (s, 3H, H-25), 1.11 (s,
6H, H-28 and H-26), 1.03 (ddd, 1H, H-10, J = 13.7, 13.7, 3.77 Hz),
0.99 (m, 1H, H-150), 0.86 (s, 6H, H-23 and H-24), 0.79 (m, 1H,
H-5), 0.78 (s, 3H, H-29); 13C NMR (125 MHz, CDCl3): d = 200.0
(C-11), 175.8 (C-30), 170.1 (Gly-COO), 169.5 (C-13), 155.7 (Boc-
COO), 128.4 (C-12), 82.0 (C-3), 79.9 (Boc-quart.-C), 67.4 (i-Pr-CH),
61.7 (C-9), 55.0 (C-5), 48.4 (C-18), 45.4 (C-8), 43.7 (C-20), 43.2
(C-14), 42.7 (Gly-CH2), 41.0 (C-19), 38.7 (C-1), 38.1 (C-4), 37.7
(C-22), 36.9 (C-10), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21), 28.6
(C-29), 28.3 (Boc-CH3), 28.2 (C-23), 28.1 (C-28), 26.5 (C-16), 26.4
(C-15), 23.5 (C-2), 23.3 (C-27), 21.9 (i-Pr-CH3), 21.7 (i-Pr-CH3),
18.7 (C-26), 17.4 (C-6), 16.6 (C-24), 16.4 (C-25). Anal. Calcd for
4.2.6.34. Ethyl 3b-(Boc-b-alanyl)-11-oxo-olean-12-en-30-oate
(34). Obtained from 2 and Boc-b-Ala by method A as a colourless
powder; yield: 225 mg, 55%; mp 79–82 °C; Rf = 0.59 (hexane/ethyl
acetate 7:3); ½a D20
ꢂ
= 108.65 (c 0.55, CHCl3); UV–vis (MeOH): kmax
C40H63NO7 (669.93): C, 71.71; H, 9.48; N, 2.09. Found: C, 71.56;
H, 9.64; N, 1.94.
(log
e
) = 250 nm (4.07); MS (ESI): m/z (%) = 670.3 ([M+H]+, 42),
692.5 ([M+Na]+, 100), 1024.9 ([3M+K+H]2+
,
30), 1027.5
= 3421 (br),
([3M+2Na]2+, 34), 1362.3 ([2M+Na]+, 50); IR (KBr):
m
4.2.6.36. i-Propyl 3b-(Boc-
L
-alanyl)-11-oxo-olean-12-en-30-oate
2975 (s), 1727 (s), 1660 (m), 1508 (w), 1457 (w), 1389 (m), 1366
(36). Obtained from 3 and Boc-L-Ala by method A as a colourless
(m), 1325 (w), 1249 (m), 1215 (m), 1174 (s), 1086 (w), 1020 (w),
powder; yield: 280 mg, 75%; mp 224–228 °C (decomp.); Rf = 0.59
985 (w), 862 (w), 770 (w), 543 (w) cmꢃ1
;
1H NMR (500 MHz,
(hexane/ethyl acetate 7:3); ½a D20
ꢂ
= 93.61 (c 0.29, CHCl3); UV–vis
(MeOH): kmax (log e) = 249 nm (4.10); MS (ESI): m/z (%) = 684.0
CDCl3): d = 5.64 (s, 1H, H-12), 4.96 (br, 1H, Ala-NH), 4.54 (dd, 1H,
H-3, J = 11.7, 4.87 Hz), 4.18 (dq, 1H, COOCHH0, J = 10.7, 7.27 Hz),
4.12 (dq, 1H, COOCHH0, J = 10.7, 7.27 Hz), 3.39 (dt, 2H, Ala-NHCH2,
J = 5.9, 5.97 Hz), 2.81 (ddd, 1H, H-1, J = 13.7, 3.7, 3.77 Hz), 2.52 (m,
2H, CH2COO), 2.36 (s, 1H, H-9), 2.10 (dd, 1H, H-18, J = 13.7,
3.87 Hz), 2.03 (ddd, 1H, H-15, J = 13.6, 13.6, 4.57 Hz), 1.99 (m,
1H, H-21), 1.92 (ddd, 1H, H-19, J = 13.7, 4.0, 2.77 Hz), 1.82 (ddd,
1H, H-16, J = 13.4, 13.4, 4.97 Hz), 1.71 (m, 1H, H-2), 1.68 (m, 1H,
H-7), 1.60 (dd, 1H, H-190, J = 13.7, 13.77 Hz), 1.58 (m, 1H, H-20),
1.57 (m, 1H, H-6), 1.46 (m, 1H, H-60), 1.43 (s, 9H, Boc-CH3), 1.40
(m, 1H, H-70), 1.38 (m, 1H, H-22), 1.36 (s, 3H, H-27), 1.33 (m, 1H,
H-220), 1.31 (m, 1H, H-210), 1.26 (t, 3H, COOCH2CH3, J = 7.17 Hz),
1.17 (m, 1H, H-160), 1.15 (s, 3H, H-25), 1.14 (s, 3H, H-28), 1.12 (s,
3H, H-26), 1.04 (ddd, 1H, H-10, J = 13.7, 13.7, 3.77 Hz), 1.01
(m, 1H, H-150), 0.87 (s, 3H, H-23), 0.86 (s, 3H, H-24), 0.80 (s, 3H,
H-29), 0.79 (m, 1H, H-5); 13C NMR (125 MHz, CDCl3): d = 200.0
(C-11), 176.3 (C-30), 172.7 (Ala-COO), 169.3 (C-13), 156.9 (Boc-
COO), 128.4 (C-12), 81.1 (C-3), 79.7 (Boc-quart.-C), 61.7 (C-9),
60.3 (COOCH2), 55.0 (C-5), 48.4 (C-18), 45.4 (C-8), 43.8 (C-20),
43.2 (C-14), 41.0 (C-19), 38.7 (C-1 and CH2COO), 38.0 (C-4 and
CH2NH), 37.7 (C-22), 36.9 (C-10), 32.7 (C-7), 31.8 (C-17), 31.1
(C-21), 28.5 (C-29), 28.4 (Boc-CH3), 28.3 (C-23), 28.1 (C-28), 26.5
(C-16), 26.4 (C-15), 23.6 (C-2), 23.3 (C-27), 18.7 (C-26), 17.4
(C-6), 16.7 (C-24), 16.4 (C-25), 14.3 (COOCH2CH3). Anal. Calcd for
([M+H]+, 7), 706.4 ([M+Na]+, 100), 1048.3 ([3M+2Na]2+, 6), 1389.2
([2M+Na]+, 18); IR (KBr):
= 3443 (br), 3388 (m), 2978 (s), 2876
m
(m), 1724 (s), 1656 (s), 1618 (w), 1496 (m), 1454 (s), 1368 (s),
1354 (m), 1311 (m), 1280 (m), 1248 (m), 1216 (s), 1170 (s), 1110
(m), 1087 (m), 1053 (m), 1022 (m), 972 (w), 916 (w), 879 (w),
863 (w), 770 (w), 671 (w), 466 (w) cmꢃ1 1H NMR (400 MHz,
;
CDCl3): d = 5.60 (s, 1H, H-12), 5.04 (m, 1H, Ala-NH), 5.01 (qq, 1H,
i-Pr-CH, J = 6.2, 6.27 Hz), 4.54 (dd, 1H, H-3, J = 11.7, 4.87 Hz), 4.28
(m, 1H, Ala-CH), 2.79 (ddd, 1H, H-1, J = 13.7, 3.4, 3.47 Hz), 2.34 (s,
1H, H-9), 2.08 (dd, 1H, H-18, J = 13.3, 3.37 Hz), 2.01 (dd, 1H,
H-15, J = 13.7, 4.67 Hz), 1.96 (m, 1H, H-21), 1.89 (ddd, 1H, H-19,
J = 13.6, 4.2, 2.37 Hz), 1.80 (ddd, 1H, H-16, J = 13.7, 13.7, 4.37 Hz),
1.72 (m, 1H, H-2), 1.64 (m, 1H, H-7), 1.60 (m, 1H, H-20), 1.58 (dd,
1H, H-190, J = 13.6, 13.67 Hz), 1.56 (m, 1H, H-6), 1.44 (m, 1H, H-
60), 1.42 (s, 9H, Boc-CH3), 1.40 (m, 1H, H-70), 1.38 (d, 3H, Ala-CH3,
J = 7.27 Hz), 1.35 (m, 1H, H-22), 1.34 (s, 3H, H-27), 1.31 (m, 2H,
H-220 and H-210), 1.23 (d, 3H, i-Pr-CH3, J = 6.27 Hz), 1.20 (d, 3H, i-
Pr-CH3, J = 6.27 Hz), 1.16 (m, 1H, H-160), 1.14 (s, 3H, H-25), 1.10
(s, 6H, H-28 and H-26), 1.03 (m, 1H, H-10), 0.99 (m, 1H, H-150),
0.87 (s, 3H, H-23), 0.85 (s, 3H, H-24), 0.79 (m, 1H, H-5), 0.77 (s,
3H, H-29); 13C NMR (125 MHz, CDCl3): d = 200.0 (C-11), 175.8
(C-30), 173.0 (Ala-COO), 169.4 (C-13), 155.0 (Boc-COO), 128.4
(C-12), 81.7 (C-3), 79.6 (Boc-quart.-C), 67.3 (i-Pr-CH), 61.7 (C-9),
55.0 (C-5), 49.5 (Ala-CH), 48.4 (C-18), 45.4 (C-8), 43.7 (C-20),
43.2 (C-14), 41.0 (C-19), 38.7 (C-1), 38.2 (C-4), 37.7 (C-22), 36.9
C40H63NO7 (669.93): C, 71.71; H, 9.48; N, 2.09. Found: C, 71.52;
H, 9.56; N, 2.01.

7472
S. Schwarz, R. Csuk / Bioorg. Med. Chem. 18 (2010) 7458–7474
(C-10), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21), 28.6 (C-29), 28.3 (Boc-
CH3), 28.2 (C-23), 28.0 (C-28), 26.5 (C-16), 26.4 (C-15), 23.5 (C-2),
23.3 (C-27), 21.9 (i-Pr-CH3), 21.7 (i-Pr-CH3), 18.8 (Ala-CH3), 18.7
(C-26), 17.3 (C-6), 16.7 (C-24), 16.3 (C-25). Anal. Calcd for
(m, 1H, H-220), 1.16 (s, 3H, H-25), 1.16 (s, 3H, H-28), 1.14 (m, 1H,
H-160), 1.10 (s, 3H, H-26), 1.04 (ddd, 1H, H-10, J = 13.3, 13.3,
3.67 Hz), 0.99 (m, 1H, H-150), 0.87 (s, 6H, H-24 and H-23), 0.79
(m, 1H, H-5), 0.73 (s, 3H, H-29); 13C NMR (125 MHz, CDCl3):
d = 199.9 (C-11), 176.2 (C-30), 170.0 (Gly-COO), 169.1 (C-13),
155.7 (Boc-COO), 136.1 (Car), 128.6 (Car), 128.6 (Car), 128.4 (C-
12), 128.3 (Car), 128.2 (Car), 128.2 (Car), 82.0 (C-3), 77.2 (Boc-
quart.-C), 66.2 (Bn-CH2), 61.6 (C-9), 55.0 (C-5), 48.2 (C-18), 45.3
(C-8), 44.0 (C-20), 43.2 (C-14), 42.8 (Gly-CH2), 41.1 (C-19), 38.7
(C-1), 38.1 (C-4), 37.6 (C-22), 36.9 (C-10), 32.7 (C-7), 31.8 (C-17),
31.2 (C-21), 28.4 (C-29), 28.3 (Boc-CH3), 28.3 (C-23), 28.1 (C-28),
26.5 (C-16), 26.4 (C-15), 23.5 (C-2), 23.3 (C-27), 18.7 (C-26), 17.4
C41H65NO7 (683.96): C, 72.00; H, 9.58; N, 2.05. Found: C, 71.88;
H, 9.71; N, 1.96.
4.2.6.37. i-Propyl 3b-(Boc-b-alanyl)-11-oxo-olean-12-en-30-oate
(37). Obtained from 3 and Boc-b-Ala by method A as a colourless
powder; yield: 400 mg, 97%; mp 114–116 °C (decomp.); Rf = 0.44
(hexane/ethyl acetate 7:3); ½a D20
ꢂ
= 98.00 (c 0.50, CHCl3); UV–vis
(MeOH): kmax (log e) = 250 nm (4.05); MS (ESI): m/z (%) = 684.2
([M+H]+, 22), 706.3 ([M+Na]+, 100), 1048 ([3M+2Na]2+
1390.2 ([2M+Na]+, 30); IR (KBr):
= 3405 (br), 2977 (s), 1724 (s),
,
28),
(C-6), 16.6 (C-24), 16.4 (C-25). Anal. Calcd for C44H63NO7
(717.97): C, 73.61; H, 8.84; N, 1.95. Found: C, 73.52; H, 8.69; N,
1.85.
m
1660 (s), 1509 (m), 1456 (m), 1389 (m), 1366 (m), 1326 (w),
1280 (m), 1250 (m), 1217 (m), 1174 (s), 1109 (m), 1086 (w),
1020 (w), 985 (w), 879 (w), 770 (w), 543 (w) cmꢃ1
;
1H NMR
4.2.6.39. Benzyl 3b-(Boc-
(39). Obtained from 4 and Boc-
L
-alanyl)-11-oxo-olean-12-en-30-oate
-Ala by method A as a colourless
(400 MHz, CDCl3): d = 5.60 (s, 1H, H-12), 5.02 (qq, 1H, i-Pr-CH,
J = 6.2, 6.27 Hz), 4.95 (m, 1H, Ala-NH), 4.52 (dd, 1H, H-3, J = 11.7,
5.07 Hz), 3.37 (dt, 2H, Ala-CH2NH2, J = 5.8, 5.87 Hz), 2.79 (ddd,
1H, H-1, J = 13.7, 3.4, 3.47 Hz), 2.47 (t, 2H, Ala-CH2COO,
J = 6.27 Hz), 2.34 (s, 1H, H-9), 2.09 (dd, 1H, H-18, J = 12.9,
3.77 Hz), 2.01 (ddd, 1H, H-15, J = 13.6, 13.6, 4.57 Hz), 1.96 (m,
1H, H-21), 1.89 (ddd, 1H, H-19, J = 13.3, 3.3, 2.57 Hz), 1.80 (ddd,
1H, H-16, J = 13.8, 13.8, 4.77 Hz), 1.71 (ddd, 1H, H-2, J = 13.3,
13.3, 3.37 Hz), 1.66 (m, 1H, H-7), 1.59 (m, 1H, H-20), 1.58 (dd, 1H,
H-190, J = 13.5, 13.57 Hz), 1.55 (m, 1H, H-6), 1.44 (m, 1H, H-60),
1.41 (s, 9H, Boc-CH3), 1.38 (m, 1H, H-70), 1.37 (m, 1H, H-22), 1.35
(s, 3H, H-27), 1.33 (m, 1H, H-220), 1.27 (m, 1H, H-210), 1.23 (d,
3H, i-Pr-CH3, J = 6.27 Hz), 1.20 (d, 3H, i-Pr-CH3, J = 6.27 Hz), 1.19
(m, 1H, H-160), 1.14 (s, 3H, H-25), 1.10 (s, 6H, H-28 and H-26),
1.03 (ddd, 1H, H-10, J = 13.5, 13.5, 3.57 Hz), 0.99 (m, 1H, H-150),
0.86 (s, 3H, H-24), 0.85 (s, 3H, H-23), 0.79 (m, 1H, H-5), 0.78 (s,
3H, H-29); 13C NMR (125 MHz, CDCl3): d = 200.0 (C-11), 175.8
(C-30), 172.1 (Ala-COO), 169.5 (C-13), 156.6 (Boc-COO), 128.4
(C-12), 81.1 (C-3), 79.5 (Boc-quart.-C), 67.3 (i-Pr-CH), 61.7 (C-9),
55.0 (C-5), 48.4 (C-18), 45.4 (C-8), 43.7 (C-20), 43.2 (C-14), 41.0
(C-19), 38.7 (C-1), 38.0 (C-4), 37.7 (C-22), 36.9 (C-10), 36.3 (Ala-
CH2NH2), 34.9 (Ala-CH2COO), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21),
28.6 (C-29), 28.4 (Boc-CH3), 28.2 (C-28), 28.1 (C-23), 26.5 (C-16),
26.4 (C-15), 23.6 (C-2), 23.3 (C-27), 21.9 (i-Pr-CH3), 21.7 (i-Pr-
CH3), 18.7 (C-26), 17.4 (C-6), 16.7 (C-24), 16.4 (C-25). Anal. Calcd
for C41H65NO7 (683.96): C, 72.00; H, 9.58; N, 2.05. Found: C,
71.86; H, 9.63; N, 1.85.
L
powder; yield: 430 mg, 46%; mp 199–203 °C (decomp.); Rf = 0.59
(hexane/ethyl acetate 7:3); ½a D20
ꢂ
= 101.74 (c 0.24, CHCl3); UV–vis
(MeOH): kmax (log e) = 206 nm (4.16), 250 nm (4.16); MS (ESI):
m/z (%) = 754.4 ([M+Na]+, 100), 1120.3 ([3M+2Na]2+, 8), 1485.2
([2M+Na]+, 14); IR (KBr):
= 3440 (br), 2969 (s), 2876 (m), 1731
m
(s), 1715 (s), 1654 (s), 1496 (m), 1455 (m), 1398 (m), 1366 (m),
1215 (s), 1162 (s), 1086 (m), 1050 (m), 1026 (m), 986 (w), 970
(w), 914 (w), 879 (s), 861 (w), 768 (w), 745 (w), 733 (w), 697
(w), 670 (w), 586 (w), 475 (w) cmꢃ1 1H NMR (400 MHz, CDCl3):
;
d = 7.38–7.28 (m, 5H, H-Ar), 5.53 (s, 1H, H-12), 5.18 (d, 1H, Bn-
CHH0, J = 12.47 Hz), 5.07 (d, 1H, Bn-CHH0, J = 12.47 Hz), 5.04 (m,
1H, Ala-NH), 4.54 (dd, 1H, H-3, J = 11.8, 4.77 Hz), 4.28 (m, 1H,
Ala-CH), 2.80 (ddd, 1H, H-1, J = 13.7, 3.3, 3.37 Hz), 2.32 (s, 1H,
H-9), 2.02 (m, 1H, H-18), 2.00 (m, 1H, H-15), 1.97 (m, 1H, H-21),
1.92 (m, 1H, H-19), 1.79 (ddd, 1H, H-16, J = 13.7, 13.7, 4.27 Hz),
1.72 (m, 1H, H-2), 1.65 (m, 1H, H-7), 1.61 (m, 1H, H-20), 1.60 (dd,
1H, H-190, J = 13.4, 13.47 Hz), 1.57 (m, 1H, H-6), 1.45 (m, 1H, H-
60), 1.43 (s, 9H, Boc-CH3), 1.41 (m, 1H, H-70), 1.38 (m, 1H, H-22),
1.38 (d, 3H, Ala-CH3, J = 7.0), 1.33 (s, 3H, H-27), 1.29 (m, 2H,
H-220 and H-210), 1.16 (m, 1H, H-160), 1.14 (s, 6H, H-25 and
H-28), 1.09 (s, 3H, H-26), 1.03 (m, 1H, H-10), 0.98 (m, 1H, H-150),
0.87 (s, 3H, H-23), 0.85 (s, 3H, H-24), 0.78 (m, 1H, H-5), 0.72
(s, 3H, H-29); 13C NMR (125 MHz, CDCl3): d = 199.9 (C-11), 176.2
(C-30), 173.0 (Ala-COO), 169.0 (C-13), 155.0 (Boc-COO), 136.1
(Car), 128.6 (Car), 128.6 (Car), 128.4 (C-12), 128.3 (Car), 128.2 (Car),
128.2 (Car), 81.7 (C-3), 78.3 (Boc-quart.-C), 66.2 (Bn-CH2), 61.6
(C-9), 55.0 (C-5), 49.6 (Ala-CH), 48.2 (C-18), 45.3 (C-8), 44.0
(C-20), 43.1 (C-14), 41.0 (C-19), 38.7 (C-1), 38.2 (C-4), 37.6 (C-
22), 36.9 (C-10), 32.7 (C-7), 31.7 (C-17), 31.1 (C-21), 28.4 (C-29),
28.3 (Boc-CH3), 28.2 (C-23), 28.0 (C-28), 26.4 (C-16), 26.4 (C-15),
23.5 (C-2), 23.3 (C-27), 18.9 (Ala-CH3), 18.6 (C-26), 17.3 (C-6),
16.7 (C-24), 16.4 (C-25). Anal. Calcd for C45H65NO7 (732.00): C,
73.84; H, 8.95; N, 1.91. Found: C, 73.77; H, 9.01; N, 1.78.
4.2.6.38. Benzyl 3b-(Boc-glycyl)-11-oxo-olean-12-en-30-oate
(38). Obtained from 4 and Boc-Gly by method A as a colourless
powder; yield: 120 mg, 47%; mp 186–189 °C (decomp.); Rf = 0.55
(hexane/ethyl acetate 7:3); ½a D20
ꢂ
= 107.04 (c 0.51, CHCl3); UV–vis
(MeOH): kmax (log e) = 205 (4.03), 250 nm (4.05); MS (ESI): m/z
(%) = 740.4 ([M+Na]+, 100), 1099.3 ([3M+2Na]2+, 17.3), 1458.2
([2M+Na]+, 20.2); IR (KBr):
= 3398 (br), 2973 (s), 2873 (m),
m
1727 (s), 1660 (s), 1619 (w), 1499 (m), 1456 (m), 1388 (m), 1366
(s), 1280 (m), 1249 (m), 1213 (s), 1165 (s), 1085 (m), 1052 (w),
1028 (w), 984 (m), 915 (w), 881 (w), 866 (w), 768 (w), 752 (w),
4.2.6.40. Benzyl 3b-(Boc-b-alanyl)-11-oxo-olean-12-en-30-oate
(40). Obtained from 4 and Boc-b-Ala by method A as a colourless
powder; yield: 600 mg, 66%; mp 176–179 °C (decomp.); Rf = 0.36
698 (w), 670 (w), 586 (w), 464 (w) cmꢃ1
;
1H NMR (400 MHz,
(hexane/ethyl acetate 7:3); ½a D20
ꢂ
= 132.62 (c 0.34, MeOH); UV–vis
(MeOH): kmax (log e) = 207 nm (4.06), 250 nm (4.10); MS (ESI):
CDCl3): d = 7.40–7.31 (m, 5H, H-Ar), 5.54 (s, 1H, H-12), 5.20 (d,
1H, Bn-CHH0, J = 12.57 Hz), 5.08 (d, 1H, Bn-CHH0, J = 12.57 Hz),
4.98 (m, 1H, Gly-NH), 4.58 (dd, 1H, H-3, J = 11.7, 4.77 Hz), 3.90
(d, 2H, Gly-CH2, J = 5.17 Hz), 2.81 (ddd, 1H, H-1, J = 13.6, 3.3,
3.37 Hz), 2.33 (s, 1H, H-9), 2.03 (m 1H, H-18), 2.02 (m, 1H, H-15),
2.01 (m, 1H, H-21), 1.93 (m, 1H, H-19), 1.80 (ddd, 1H, H-16,
J = 13.9, 13.9, 4.87 Hz), 1.73 (m, 1H, H-2), 1.65 (m, 1H, H-7), 1.62
(m, 1H, H-20), 1.61 (dd, 1H, H-190, J = 13.6, 13.6), 1.57 (m, 1H, H-
6), 1.45 (s, 9H, Boc-CH3), 1.43 (m, 1H, H-60), 1.41 (m, 1H, H-70),
1.38 (m, 1H, H-22), 1.34 (s, 3H, H-27), 1.32 (m, 1H, H-210), 1.29
m/z (%) = 732.3 ([M+H]+, 14), 754.4 ([M+Na]+, 100), 763.3
([M+MeOH]+, 6), 770.3 ([M+K]+, 20); IR (KBr):
= 3436 (br), 2964
m
(s), 2873 (m), 1725 (s), 1654 (s), 1498 (m), 1456 (m), 1390 (m),
1365 (m), 1331 (m), 1256 (m), 1213 (m), 1170 (s), 1146 (s), 1076
(w), 1063 (w), 1022 (w), 984 (w), 915 (w), 878 (s), 756 (w), 699
(w), 545 (w) cmꢃ1 1H NMR (400 MHz, CDCl3): d = 7.38–7.28
;
(m, 5H, H-Ar), 5.52 (s, 1H, H-12), 5.18 (d, 1H, Bn-CHH0,
J = 12.57 Hz), 5.06 (d, 1H, Bn-CHH0, J = 12.57 Hz), 4.94 (m, 1H,
Ala-NH), 4.52 (dd, 1H, H-3, J = 11.7, 5.27 Hz), 3.37 (dt, 2H,

S. Schwarz, R. Csuk / Bioorg. Med. Chem. 18 (2010) 7458–7474
7473
Ala-CH2NH2, J = 5.8, 5.87 Hz), 2.78 (ddd, 1H, H-1, J = 13.8, 3.8,
3.87 Hz), 2.50 (m, 2H, Ala-CH2COO), 2.32 (s, 1H, H-9), 2.02 (m
1H, H-18), 1.97 (m, 1H, H-15), 1.96 (m, 1H, H-21), 1.92 (m, 1H,
H-19), 1.78 (ddd, 1H, H-16, J = 13.9, 13.9, 4.17 Hz), 1.71 (m, 1H,
H-2), 1.64 (m, 1H, H-7), 1.60 (m, 1H, H-20), 1.59 (dd, 1H, H-190,
J = 13.6, 13.67 Hz), 1.55 (m, 1H, H-6), 1.44 (m, 1H, H-60), 1.41 (s,
9H, Boc-CH3), 1.38 (m, 1H, H-70), 1.33 (m, 1H, H-22), 1.33 (s, 3H,
H-27), 1.31 (m, 1H, H-210), 1.28 (m, 1H, H-220), 1.15 (m, 1H,
H-160), 1.14 (s, 6H, H-25 and H-28), 1.09 (s, 3H, H-26), 1.02 (m
1H, H-10), 0.97 (m, 1H, H-150), 0.86 (s, 3H, H-24), (s, 3H, H-23),
0.77 (m, 1H, H-5), 0.71 (s, 3H, H-29); 13C NMR (125 MHz, CDCl3):
d = 199.9 (C-11), 176.1 (C-30), 172.1 (Ala-COO), 169.0 (C-13),
155.7 (Boc-COO), 136.1 (Car), 128.6 (Car), 128.6 (Car), 128.4
(C-12), 128.3 (Car), 128.2 (Car), 128.2 (Car), 81.1 (C-3), 77.3 (Boc-
quart.-C), 66.2 (Bn-CH2), 61.6 (C-9), 55.0 (C-5), 48.2 (C-18), 45.3
(C-8), 44.0 (C-20), 43.2 (C-14), 41.0 (C-19), 38.8 (C-1), 38.0 (C-4),
37.6 (C-22), 36.9 (C-10), 36.5 (Ala-CH2COO), 34.9 (Ala-COO), 32.7
(C-7), 31.7 (C-17), 31.1 (C-21), 28.4 (C-29), 28.4 (Boc-CH3), 28.2
(C-23), 28.1 (C-28), 26.4 (C-16), 26.4 (C-15), 23.6 (C-2), 23.3
(C-27), 18.6 (C-26), 17.4 (C-6), 16.7 (C-24), 16.4 (C-25). Anal. Calcd
for C45H65NO7 (732.00): C, 73.84; H, 8.95; N, 1.91. Found: C, 73.74;
H, 9.11; N, 1.69.
1575 (w), 1514 (m), 1454 (m), 1389 (m), 1366 (m), 1313 (m),
1246 (m), 1215 (s), 1168 (s), 1088 (m), 1074 (m), 1049 (m), 1024
(m), 966 (w), 916 (w), 880 (w), 865 (w), 753 (s), 666 (w), 602
(w) cmꢃ1 1H NMR (400 MHz, CDCl3): d = 5.65 (s, 1H, H-12), 5.03
;
(m, 1H, Ala-NH), 4.52 (dd, 1H, H-3, J = 11.6, 4.67 Hz), 4.30 (m, 1H,
Ala-CH), 4.16 (dq, 1H, COOCHH0, J = 10.8, 7.17 Hz), 4.11 (dq, 1H,
COOCHH0, J = 10.8, 7.17 Hz), 2.80 (ddd, 1H, H-1, J = 13.7, 3.8,
3.87 Hz), 2.34 (s, 1H, H-9), 2.08 (dd, 1H, H-18, J = 13.6, 3.77 Hz),
2.01 (m, 1H, H-15), 1.97 (m, 1H, H-21), 1.90 (m, 1H, H-19), 1.81
(m, 1H, H-16), 1.71 (m, 1H, H-2), 1.66 (m, 1H, H-7), 1.60 (m, 1H,
H-20), 1.59 (dd, 1H, H-190, J = 13.3, 13.37 Hz), 1.56 (m, 1H, H-6),
1.44 (m, 1H, H-60), 1.41 (s, 9H, Boc-CH3), 1.39 (m, 1H, H-70), 1.36
(m, 1H, H-22), 1.35 (s, 3H, H-27), 1.35 (d, 3H, Ala-CH3,
J = 7.17 Hz), 1.29 (m, 1H, H-220), 1.27 (m, 1H, H-210), 1.24 (t, 3H,
Et-CH3, J = 7.17 Hz), 1.16 (m, 1H, H-160), 1.14 (s, 3H, H-25), 1.12
(s, 3H, H-28), 1.10 (s, 3H, H-26), 1.04 (m, 1H, H-10), 0.99 (m, 1H,
H-150), 0.86 (s, 3H, H-23), 0.86 (s, 3H, H-24), 0.80 (m, 1H, H-5),
0.79 (s, 3H, H-29); 13C NMR (125 MHz, CDCl3): d = 200.0 (C-11),
176.3 (C-30), 171.8 (Ala-COO), 169.4 (C-13), 155.0 (Boc-COO),
128.4 (C-12), 81.6 (C-3), 78.1 (Boc-quart.-C), 61.7 (C-9), 60.3
(Et-CH2), 55.0 (C-5), 50.8 (Ala-CH), 48.4 (C-18), 45.4 (C-8), 43.8
(C-20), 43.2 (C-14), 41.0 (C-19), 38.6 (C-1), 38.1 (C-4), 37.7
(C-22), 36.9 (C-10), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21), 28.5
(C-29), 28.3 (C-23), 28.0 (C-28), 26.5 (C-16), 26.4 (C-15), 23.3
(C-2), 23.3 (C-27), 18.8 (Ala-CH3), 18.6 (C-26), 17.3 (C-6), 16.6
(C-24), 16.4 (C-25), 14.3 (Et-CH3). Anal. Calcd for C40H63NO7
(669.93): C, 71.71; H, 9.48; N, 2.09. Found: C, 71.52; H, 9.63; N,
1.86.
4.2.6.41. Methyl 3b-(Boc-D-alanyl)-11-oxo-olean-12-en-30-oate
(41). Obtained from 1 and Boc-
D
-Ala by method A as a colourless
powder; yield: 450 mg, 97%; mp 205–208 °C (decomp.); Rf = 0.74
(hexane/ethyl acetate 7:3); ½a D20
ꢂ
= 82.74 (c 0.41, CHCl3); UV–vis
(MeOH): kmax (log e) = 249 nm (3.97); MS (ESI): m/z (%) = 656.0
([M+H]+, 8), 678.3 ([M+Na]+, 100), 1006.3 ([3M+2Na]2+
1334.1 ([2M+Na]+, 14); IR (KBr):
= 3371 (br), 2950 (s), 2874
, 12),
m
(m), 1734 (s), 1718 (s), 1650 (s), 1509 (m), 1455 (m), 1388 (m),
1366 (m), 1306 (m), 1248 (m), 1216 (s), 1168 (s), 1088 (w), 1074
(m), 1049 (w), 1023 (w), 986 (w), 916 (w), 882 (w), 866 (w), 851
4.2.6.43. i-Propyl 3b-(Boc-
(43). Obtained from 3 and Boc-
D
-alanyl)-11-oxo-olean-12-en-30-oate
-Ala by method A as a colourless
D
powder; yield: 380 mg, 84%; mp 178–181 °C (decomp.); Rf = 0.55
(w), 834 (w), 754 (s), 666 (w), 601 (w) cmꢃ1 1H NMR (400 MHz,
;
(hexane/ethyl acetate 7:3); ½a D20
ꢂ
= 101.37 (c 0.39, CHCl3); UV–vis
CDCl3): d = 5.64 (s, 1H, H-12), 5.03 (m, 1H, Ala-NH), 4.53 (dd, 1H,
H-3, J = 11.6, 4.47 Hz), 4.27 (m, 1H, Ala-CH), 3.67 (s, 3H, OMe),
2.80 (ddd, 1H, H-1, J = 13.7, 3.8, 3.87 Hz), 2.34 (s, 1H, H-9), 2.06
(dd, 1H, H-18, J = 13.7, 3.77 Hz), 2.00 (m, 1H, H-15), 1.97 (m, 1H,
H-21), 1.90 (ddd, 1H, H-19, J = 13.7, 3.3, 2.97 Hz), 1.80 (ddd, 1H,
H-16, J = 13.7, 13.7, 4.67 Hz), 1.70 (m, 1H, H-2), 1.64 (m, 1H, H-
7), 1.61 (m, 1H, H-20), 1.59 (dd, 1H, H-190, J = 13.7, 13.77 Hz),
1.57 (m, 1H, H-6), 1.44 (m, 1H, H-60), 1.42 (s, 9H, Boc-CH3), 1.41
(m, 1H, H-70), 1.37 (m, 1H, H-22), 1.35 (d, 3H, Ala-CH3,
J = 7.17 Hz), 1.34 (s, 3H, H-27), 1.29 (m, 2H, H-220 and H-210),
1.16 (m, 1H, H-160), 1.14 (s, 3H, H-25), 1.13 (s, 3H, H-28), 1.10 (s,
3H, H-26), 1.03 (ddd, 1H, H-10, J = 13.7, 13.7, 3.77 Hz), 1.00 (m,
1H, H-150), 0.87 (s, 6H, H-23 and H-24), 0.79 (m, 1H, H-5), 0.78
(s, 3H, H-29); 13C NMR (125 MHz, CDCl3): d = 200.0 (C-11), 176.9
(C-30), 172.0 (Ala-COO), 169.3 (C-13), 155.0 (Boc-COO), 128.5 (C-
12), 81.7 (C-3), 78.4 (Boc-quart.-C), 61.7 (C-9), 55.0 (C-5), 51.8
(OMe), 50.6 (Ala-CH), 48.4 (C-18), 45.4 (C-8), 44.0 (C-20), 43.2
(C-14), 41.1 (C-19), 38.7 (C-1), 38.1 (C-4), 37.7 (C-22), 36.9
(C-10), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21), 28.5 (C-29), 28.3
(C-23 and Boc-CH3), 28.0 (C-28), 26.5 (C-16), 26.4 (C-15), 23.4
(C-2), 23.3 (C-27), 18.8 (Ala-CH3), 18.7 (C-26), 17.3 (C-6), 16.6
(C-24), 16.4 (C-25). Anal. Calcd for C39H61NO7 (655.90): C, 71.42;
H, 9.37; N, 2.14. Found: C, 71.28; H, 9.54; N, 1.95.
(MeOH): kmax (log e) = 250 nm (4.04); MS (ESI): m/z (%) = 684.1
([M+H]+, 10), 706.3 ([M+Na]+, 100), 1048.3 ([3M+2Na]2+
1390.1 ([2M+Na]+, 13); IR (KBr):
= 3382 (br), 2978 (s), 2876
, 8),
m
(m), 1723 (s), 1661 (s), 1621 (w), 1499 (m), 1455 (s), 1389 (s),
1367 (s), 1312 (m), 1249 (m), 1216 (s), 1171 (s), 1109 (s), 1087
(m), 1086 (m), 1022 (m), 973 (m), 916 (w), 880 (w), 864 (w), 770
(w), 669 (w), 539 (w), 464 (w) cmꢃ1 1H NMR (400 MHz, CDCl3):
;
d = 5.60 (s, 1H, H-12), 5.04 (m, 1H, Ala-NH), 5.01 (qq, 1H, i-Pr-CH,
J = 6.5, 6.57 Hz), 4.53 (dd, 1H, H-3, J = 11.7, 4.67 Hz), 4.27 (m, 1H,
Ala-CH), 2.79 (ddd, 1H, H-1, J = 13.7, 3.5, 3.57 Hz), 2.34 (s, 1H, H-
9), 2.09 (dd, 1H, H-18, J = 13.3, 3.77 Hz), 2.01 (dd, 1H, H-15,
J = 13.3, 5.07 Hz), 1.96 (m, 1H, H-21), 1.89 (ddd, 1H, H-19,
J = 13.7, 4.2, 2.57 Hz), 1.80 (ddd, 1H, H-16, J = 13.8, 13.8, 4.57 Hz),
1.70 (m, 1H, H-2), 1.66 (m, 1H, H-7), 1.60 (m, 1H, H-20), 1.58
(dd, 1H, H-190, J = 13.2, 13.27 Hz), 1.56 (m, 1H, H-6), 1.44 (m, 1H,
H-60), 1.42 (s, 9H, Boc-CH3), 1.38 (m, 1H, H-70), 1.36 (m, 1H,
H-22), 1.35 (m, 3H, Ala-CH3), 1.34 (s, 3H, H-27), 1.33 (m, 1H,
H-220), 1.31 (m, 1H, H-210), 1.23 (d, 3H, i-Pr-CH3, J = 6.3), 1.20 (d,
3H, i-Pr-CH3, J = 6.37 Hz), 1.19 (m, 1H, H-160), 1.14 (s, 3H, H-25),
1.11 (s, 6H, H-28 and H-26), 1.03 (ddd, 1H, H-10, J = 13.3, 13.3,
3.37 Hz), 0.99 (m, 1H, H-150), 0.87 (s, 6H, H-23 and H-24), 0.79
(m, 1H, H-5), 0.78 (s, 3H, H-29); 13C NMR (125 MHz, CDCl3):
d = 200.0 (C-11), 175.8 (C-30), 171.2 (Ala-COO), 169.5 (C-13), 156.7
(Boc-COO), 128.4 (C-12), 81.6 (C-3), 79.2 (Boc-quart.-C), 67.3 (i-Pr-
CH), 61.7 (C-9), 55.0 (C-5), 49.3 (Ala-CH), 48.4 (C-18), 45.4 (C-8),
43.7 (C-20), 43.2 (C-14), 41.0 (C-19), 38.6 (C-1), 38.1 (C-4), 37.7
(C-22), 36.9 (C-10), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21), 28.6
(C-29), 28.3 (Boc-CH3), 28.2 (C-23), 28.0 (C-28), 26.5 (C-16), 26.4
(C-15), 23.3 (C-2), 23.3 (C-27), 21.9 (i-Pr-CH3), 21.7 (i-Pr-CH3), 18.8
(Ala-CH3), 18.6 (C-26), 17.3 (C-6), 16.6 (C-24), 16.3 (C-25). Anal.
Calcd for C41H65NO7 (683.96): C, 72.00; H, 9.58; N, 2.05. Found: C,
71.89; H, 9.71; N, 1.94.
4.2.6.42. Ethyl 3b-(Boc-D-alanyl)-11-oxo-olean-12-en-30-oate
(42). Obtained from 2 and Boc-
D
-Ala by method A as a colourless
powder; yield: 440 mg, 98%; mp 175–178 °C (decomp.); Rf = 0.54
(hexane/ethyl acetate 7:3); ½a D20
ꢂ
= 90.56 (c 0.29, CHCl3); UV–vis
(MeOH): kmax (log e) = 250 nm (4.03); MS (ESI): m/z (%) = 670.2
([M+H]+, 6), 692.4 ([M+Na]+, 100), 1027.3 ([3M+2Na]2+
1339.3 ([2M+H]+, 8), 1361.3 ([2M+Na]+, 24); IR (KBr):
= 3366
(br), 2979 (s), 2873 (m), 1715 (s), 1698 (s), 1649 (s), 1625 (m),
, 14)
m

7474
S. Schwarz, R. Csuk / Bioorg. Med. Chem. 18 (2010) 7458–7474
11. Liu, D.; Song, D.; Guo, G.; Wang, R.; Lv, J.; Jing, Y.; Zhao, L. Bioorg. Med. Chem.
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We like to thank Dr. Harish Kommera and PD Dr. Reinhard Pas-
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sonal scholarship (to S.S.). Many thanks are due to Dr. Ralph Kluge
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