Synthesis and cytotoxic activity of methyl glycyrrhetinate esterified with amino acids

Article abstract of DOI:10.5560/ZNB.2012-0107

Methyl glycyrrhetinate was esterified at position C3 of ring A using different amino acids. A short, unbranched chain of four carbon atoms with two amino groups in positions 2 and 4 was shown to be the most active compound of this series (IC₅₀ = 0:8 M on liposarcoma Lipo cells). These compounds trigger apoptosis as shown by an acridine orange/ethidium bromide assay, trypan blue tests and DNAladdering experiments.

Full text of DOI:10.5560/ZNB.2012-0107

Synthesis and Cytotoxic Activity of Methyl Glycyrrhetinate Esterified
with Amino Acids
Rene´ Csuk, Stefan Schwarz, Bianka Siewert, Ralph Kluge, and Dieter Stro¨hl
Martin-Luther-Universita¨t Halle-Wittenberg, Bereich Organische Chemie, Kurt-Mothes-Str. 2,
D-06120 Halle (Saale), Germany
Reprint requests to Prof. Dr. Rene´ Csuk. Fax: 0049 345 5527030.
E-mail: rene.csuk@chemie.uni-halle.de
Z. Naturforsch. 2012, 67b, 731 – 746 / DOI: 10.5560/ZNB.2012-0107
Received April 19, 2012
Methyl glycyrrhetinate was esterified at position C3 of ring A using different amino acids. A short,
unbranched chain of four carbon atoms with two amino groups in positions 2 and 4 was shown to be
the most active compound of this series (IC50 = 0.8 M on liposarcoma Lipo cells). These compounds
trigger apoptosis as shown by an acridine orange/ethidium bromide assay, trypan blue tests and DNA-
laddering experiments.
Key words: Glycyrrhetinic Acid, Antitumor Activity, Apoptosis
Introduction
The roots of the licorice plant contain sev-
Results and Discussion
The compounds (Scheme 1, Table 1) were obtained
eral pharmacologically active substances, such as by DCC mediated esterification from the correspond-
flavonoids [1 – 10] and terpenes [11 – 13] with gly- ing N-Boc protected amino acids and the methyl ester
cyrrhizinic acid being most abundant and occurring of glycyrrhetinic acid (1). Deprotection was performed
in amounts of up to 24% [14]. Glycyrrhetinic acid either with TFA in dry DCM or by treating the com-
(GA) is the aglycon of glycyrrhizinic acid and pos- pounds with dry HCl gas in DCM (to obtain the hy-
sesses many pharmacological effects. Besides its anti- drochlorides).
inflammatory [15, 16] and antiviral [17, 18] activity, its
In a first series the influence of the side chain
anti-carcinogenic potential is of pronounced scientific was investigated using SRB tests (Table 2). The high-
interest. Glycyrrhetinic acid derivatives show cytotoxic est increase of cytotoxicity was achieved by intro-
effects against various tumor cell lines [19 – 23], but ducing amino acids possessing short sidechains like
also trigger apoptosis in cancer cells [24 – 26].
the alanyloxy or sarcosyloxy derivatives. For instance,
Herein, we targeted compounds of increased cyto- the sarcosyloxy compound 6 showed IC50 values be-
toxicity (as compared to parent glycyrrhetinic acid) tween 1.83 and 3.42 µM; compounds having a proly-
while maintaining the ability to induce apoptosis. Var- loxy (7), phenylalanyloxy (8) or methionyloxy (9) sub-
ious amino acids of different lengths and structures stituent showed moderate cytotoxic effectsin the SRB
were attached to carbon C3 while carbon C30 was es- assay with IC50 values between 5 and 25 µM. Com-
terified – based on the results of previous studies [27]. pounds having a valyloxy (10), an isoleucyloxy (11) or
The influence of the substituents on cytotoxicity result- a leucyloxy (12) group showed decreased of cytotoxic-
ing from the different polarity pattern and lipophilic- ity (>30 µM) as compared to the parent methyl ester 1.
ity along the molecule was studied in sulforhodamine
The influence of the distance between the linking
B (SRB) assays. The apoptotic behavior for some of ester group and the terminal amino group was investi-
these compounds was evaluated using an acridine or- gated using a panel of different ω-amino acid derived
ange/ethidium bromide (AO/EB) test, a trypan blue as- compounds. The data showed an optimal length of two
say as well as DNA-laddering experiments.
carbon atoms as represented for a β-alanyloxy sub-
c
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R. Csuk et al. · Methyl Glycyrrhetinate Esterified with Amino Acids
Scheme 1. Amino ester derivatives of GA methyl ester (1): a. Boc-amino acids, DCM, DMAP, DCC, 25 ◦C, 12 h (leading to
tert-butoxycarbonylated 20–33); b. TFA in DCM, 25 ◦C, 12 h or HClg in DCM, 25 ◦C, 12 h.
Table 1. Amino ester derivatives of GA
methyl ester at carbon C3.
Compound R
Compound R
Compound R
2
3
4
5
6
7
glycyl
L-alanyl
D-alanyl 10
β-alanyl 11
sarcosyl
L-prolyl
8
9
L-phenylalanyl
L-methionyl
L-valyl
14
15
16
17
18
5-aminopentanoyl
6-aminohexanoyl
8-aminooctanoyl
L-2,4-diaminobutanoyl
L-ornithyl
L-isoleucyl
L-leucyl
4-aminobutanoyl 19
12
13
L-lysyl
Table 2. Biological activity (IC50 values in
µM from SRB assays), 7 tumor cell lines;
error: ±10%.
Cell line
8505C
7.45
4.31
2.92
2.55
A253
A2780
A549
DLD-1
8.59
4.49
3.35
2.51
3.42
11.64
8.70
12.45
> 30
> 30
> 30
Lipo
7.54
4.30
3.56
2.52
MCF-7
2a
3a
4a
5a
6
7
8
9
6.26
3.61
2.26
2.50
2.46
5.56
6.41
7.48
> 30
> 30
> 30
5.99
2.98
2.24
1.72
1.83
4.58
5.50
12.56
6.89
> 30
> 30
6.42
2.77
2.26
2.40
2.13
6.91
9.94
14.84
> 30
> 30
> 30
7.10
3.54
2.25
2.50
2.49
5.49
4.60
6.06
> 30
> 30
> 30
2.50
9.62
2.50
7.96
16.93
11.47
> 30
> 30
> 30
16.15
22.32
> 30
> 30
> 30
10
11
12
a
Data from previous studies [27].
Table 3. Biological activity (IC50 values in
µM) including seven tumor cell lines and
mouse embryonic fibroblasts (NiH3T3);
error: ±10%.
Cell line 8505C A253 A2780 A549 DLD-1
Lipo MCF-7 NiH3T3
2a
7.45
2.55
3.47
3.52
5.48
4.02
6.26
2.50
3.41
3.52
4.05
3.76
5.99
1.72
2.13
2.48
4.94
4.06
6.42
2.40
3.39
3.38
5.43
3.88
8.59
2.51
3.41
4.49
6.27
4.38
7.54
2.52
3.54
4.54
5.95
4.02
7.10
2.50
2.73
3.40
4.03
2.46
5.73
3.45
3.14
3.58
6.06
6.05
5a
13
14
15
16
a
Data from previous studies [27].
stituent (5). The lowest IC50 value for this compound toxicity was investigated. All of these compounds pos-
was determined as 1.72 µM for A2780 ovarian carci- sessed IC50 values <3 µM for all tumor cell lines. In
noma cells.
particular, compound 17 showed an increased cytotox-
With the exception of compound 2, all of the deriva- icity for liposarcoma Lipo cells. Compound 19 having
tives showed a slight selectivity towards the tumor cell a lysyloxy substituent, showed the highest selectivity
lines. The selectivity was determined in a compara- in this study (Table 4).
tive test using mouse embryonic fibroblasts (NiH3T3).
Compound 16 was most selective comparing NiH3T3 for an apoptotic behavior; a rate of apoptosis between
and MCF-7 cells (Table 3). 80 and 90% was determined for these compounds (Ta-
Evaluation of a trypan blue test gave an indication
Finally, three different 2,ω-diamino acid derived ble 5). This rate is slightly higher than that of parent
substituents were used, and their influence on the cyto- glycyrrhetinic acid (73.73% [28]).
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R. Csuk et al. · Methyl Glycyrrhetinate Esterified with Amino Acids
733
Table 4. Biological activity (IC50 values
in µM) using seven tumor cell lines
and mouse fibroblasts (NiH3T3); error:
±10%.
Cell line 8505C A253 A2780 A549 DLD-1
Lipo
MCF-7 NiH3T3
17
18
19
2.89
2.49
2.40
4.04
2.21
2.43
2.59
1.98
1.58
2.35
2.53
2.43
1.48
3.01
2.27
0.80
2.70
2.51
3.01
1.55
1.75
3.05
6.24
9.98
Table 5. Apoptotic effect on A549 cells in % (± standard error, six experiments). Cells were treated with 2 (8 µM), 5 (5 µM),
13 (4 µM), 14 (4 µM), 15 (7 µM), 16 (6 µM), 17 (10 µM), 18 (4 µM) and 19 (4 µM).
Substance
Apoptosis
2
5
13
14
15
16
17
18
19
92.21±1.01 81.64±0.79 84.87±0.96 89.52±2.33 91.74±0.42 84.72±1.87 80.53±3.16 78.82±3.58 89.41±1.04
In additional experiments the derivatives were tested stances like CDODO-Me-11 (1.48 µM on HL-60 cells)
in an acridine orange/ethidium bromide (AO/EB) as- or CDODO-Me-12 (0.36 µM on HL-60 cells) [29].
say. In each experiment most (80% – 90%) of the col-
The compounds were subjected to AO/EB, trypan
lected dead cells (800–1000) showed a green fluores- blue and DNA-laddering-tests. All of the active com-
cence. This fluorescence as well as the results of the pounds triggered apoptosis in A549 cells, therefore
trypan blue test indicated that the compounds trig- making them interesting compounds for future in vivo
ger apoptosis in A549 cells. Compound 17 was addi- investigations.
tionally tested in a DNA laddering assay (A549 cells;
10 µM). The gel showed the typical fragmentation pat- Experimental Section
tern of the DNA indicating apoptosis.
Cell lines and culture conditions
The cell lines 8505C, A253, A2780, A549, DLD-1,
LIPO, MCF-7, and NiH3T3 were included in this study.
Conclusion
Cultures were maintained as monolayes in RPMI 1640
(PAA Laboratories, Pasching/Germany) supplemented with
10% heat inactivated fetal bovine serum (Biochrom AG,
In this study we investigated the influence of an
additional amino acid substituent at carbon C3 of
methyl glcyrrhetinate onto cytotoxicity. These sub-
stituents differed in structure and length of the carbon
Berlin/Germany) and penicillin/streptomycin (PAA Lab-
oratories) at 37 ◦C in a humidified atmosphere of 5%
CO2/95% air.
chain as well as in the number of amino groups.
Cytotoxicity assay [30]
The cytotoxicity of each compound was determined
in an SRB-assay. The IC50 values obtained from these
The cytotoxicity of the test compounds was evaluated us-
experiments indicated that the structure of the amino
acid’s side chain affects the cytotoxicity most. A more
lipophilic side chain leads to a decreased cytotoxic-
ity while short side chains increase cytotoxicity. Com-
pounds 8 and 9, however, do not strictly obey this rule
of thumb; this might result from stereoelectronic ef-
fects of the phenyl or the thiomethyl moiety.
The optimal linker length between a terminal amino
group and the linking carboxyl function is two car-
bons. The implementation of a second amino group
did not raise the cytotoxicity for the the compound
with the butyryl chain (17), but for the compounds 18
and 19. The tumor-to-control selectivity was altered: it
was raised by the presence of a second amino group
and by an increasing number of carbons. Compound
19 was determined to be the most selective substance
of this study. The cytotoxicity of these compounds
ing the sulforhodamine-B (SRB) (Sigma Aldrich) microcul-
ture colorimetric assay. In short, exponentially growing cells
were seeded into 96-well plates on day 0 at the appropri-
ate cell densities to prevent confluence of the cells during
the experiment. After 24 h, the cells were treated with serial
dilutions of the test compounds (0 – 100 M) for 96 h. The fi-
nal concentration of DMSO or DMF solvent 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 treat-
ment, the supernatant medium from the 96 well plates was
discarded, and the cells were fixed with 10% trichloroacetic
acid. 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 al-
ternate dispensing and aspiration procedures. Afterwards the
plates were dyed with 100 µL of 0.4% SRB (sulforhodamine
B) for about 20 min. The plates were washed with 1% acetic
is comparable to that of well-known anti-tumor sub- acid to remove the excess of the dye and allowed to air dry
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R. Csuk et al. · Methyl Glycyrrhetinate Esterified with Amino Acids
overnight. 100 µL of 10 mM Tris base solution were added unit. IR spectra were recorded on a Perkin-Elmer FT-IR spec-
to each well and absorbance was measured at 570 nm (using trometer Spectrum 1000, optical rotations on a Perkin-Elmer
a 96 well plate reader, Tecan Spectra, Crailsheim/Germany). 341 polarimeter (1 cm micro cell, 25 ◦C) and UV/Vis spec-
The IC50 was estimated by linear regression between the tra on a Perkin-Elmer unit, Lambda 14. TLC was performed
value before and after the 50% line is crossed in a dose- on silica gel (Merck 5554, detection by UV absorption). Sol-
response curve.
vents were dried according to usual procedures.
General procedure for the protection of the amino acids [33]
Apoptosis test – acridine orange/ethidium bromide
(AO/EB) [31, 32]
The amino acid (1 equiv.) was dissolved in a 1 : 1 mixture
(50 mL) 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 was allowed to stir at 25 ◦C for 12 h.
The solvent was removed under reduced pressure, and ethyl
acetate (100 mL) was added. After washing with sodium hy-
drogensulfate (10% in water, 10 mL), the mixture was ex-
tracted 3 times with ethyl acetate (3×50 mL). The combined
organic layers were washed with brine (10 mL), dried over
sodium sulphate and filtered, and the solvent was evaporated.
The crude product was used without any further purification;
an analytic sample was obtained by chromatography.
Apoptotic cell death was analyzed by acridine
orange/ethidium bromide dye using fluorescence mi-
croscopy on A549 cells. Therefore around 500 000 cells
were seeded in cell culture flasks and were allowed to grow
for 24 hours. The medium was removed afterwards and
the substance loaded medium was added. After another
24 – 48 hours the supernatant medium was collected and
centrifuged. The pellet was suspended in phosphate-buffer
saline (PBS) and centrifuged again. The liquid was removed,
and the pellet was suspended in PBS. After mixing the
suspension with a solution of AO/EB, it was analyzed under
a fluorescence microscope. While a green fluorescence
shows apoptosis, a red colored nucleus indicates necrotic
cells.
General procedure for esterification at carbon C3
(method A)
The starting material (1 equiv.) was dissolved in dry DCM
(50 mL), and 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 25 ◦C for 12 h and
filtered, and the filtrate was washed with water and brine
(10 mL each), dried over sodium sulphate and filtered, and
the solvent was evaporated. Purification was performed by
flash chromatography (silica gel, hexane-ethyl acetate, 8 : 2).
Apoptosis test – trypan blue cell counting
Approximately 500 000 cells (A549) were seeded in cell
culture flasks and were allowed to grow for 1 day. After re-
moving the medium, the substance loaded medium was intro-
duced and the flasks were incubated for about 24 – 48 hours.
The supernatant medium was collected and centrifuged; the
cell pellet was suspended in PBS and centrifuged again.
Equal amounts of a trypan blue solution (0.4% in phosphate-
buffer saline, pH = 7.2), and the suspension of the pellet in
PBS were mixed and put on chamber slides (invitrogenTM).
General procedure for the deprotection (method B)
To a solution of the Boc-protected compound in dry DCM,
trifluoroacetic acid (1 mL per 10 mL DCM) was added. The
mixture was stirred at 25 ◦C for 12 h. After completion of the
reaction (as monitored by TLC), the reaction mixture was
washed with an aq. solution of sodium hydrogen carbonate
(satd., 25 mL), the aqueous layer was extracted with DCM
(5 × 20 mL), the combined organic extracts were washed
with brine (10 mL), dried over sodium sulphate and filtered,
and the solvents were evaporated.
R
An automatic cell counter (invitrogenTM countessꢀ auto-
mated cell counter) was used for counting the cells, differing
between cells with an intact cell membrane and cells without.
Synthesis and analysis
Reagents were bought from commercial suppliers with-
out any further purification. Melting points were measured
with a Leica hot stage microscope and were not corrected.
NMR spectra were recorded on Varian Gemini 200, Gemini
2000 or Unity 500 spectrometers at 27 ◦C with tretramethyl-
General procedure for the deprotection (method C)
The Boc-protected compound was dissolved in dry DCM.
silane as an internal standard; chemical shifts δ are given After saturation with dry hydrogen chloride gas for 15 min at
in ppm, coupling constants J in Hz. The assignment of the 5 ◦C, stirring at 25 ◦C was continued for additional 12 h. Af-
signals was performed using gHSQC, gHMBC, H,H-COSY, ter completion of the reaction (as monitored by TLC), the
H,C-COSY, HET2DJ and NOESY NMR experiments. Mass solvent was removed under reduced pressure. The residue
spectra were taken on a Finnigan MAT TSQ 7000 (electro- was washed with ethyl acetate until no parent substance
spray, voltage 4.5 kV, sheath gas nitrogen) instrument. Ele- could be detected; analytic samples were obtained by re-
mental analyses were measured on a Foss-Heraeus Vario EL crystallization.
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R. Csuk et al. · Methyl Glycyrrhetinate Esterified with Amino Acids
735
Methyl (3β)-3-[(sarcosyl)oxy]-11-oxo-olean-12-en-30-oate
(6)
H, Pro-β-CHH0), 2.08 (m, 1 H, 18-H), 2.03 (m, 1 H, 15-H),
1.99 (m, 1 H, 21-H), 1.93 (m, 1 H, 19-H), 1.90 (m, 1 H, Pro-
β-CHH0), 1.84 (m, 1 H, 16-H), 1.83 (m, 2 H, Pro-γ-CH2),
1.73 (m, 1 H, 2-H), 1.67 (m, 1 H, 7-H), 1.65 (m, 1 H, 20-H),
1.61 (dd, 1 H, J = 13.6, 13.6 Hz, 190-H), 1.60 (m, 1 H, 6-
H), 1.43 (m, 1 H, 60-H), 1.42 (m, 1 H, 70-H), 1.39 (m, 1 H,
22-H), 1.36 (s, 3 H, 27-H), 1.31 (m, 2 H, 220-H and 210-H),
1.18 (m, 1 H, 160-H), 1.16 (s, 3 H, 25-H), 1.15 (s, 3 H, 29-H),
1.13 (s, 3 H, 26-H), 1.05 (ddd, 1 H, J = 13.7, 13.7, 3.5 Hz,
1-H0), 1.01 (m, 1 H, 15-H0), 0.89 (s, 3 H, 24-H), 0.87 (s, 3 H,
23-H), 0.81 (m, 1 H, 5-H), 0.80 (s, 3 H, 28-H). – 13C NMR
(125 MHz, CDCl3): δ = 199.9 (C-11), 176.9 (C-30), 174.3
(Pro-COO), 169.2 (C-13), 128.5 (C-12), 81.5 (C-3), 61.6 (C-
9), 60.0 (Pro-α-CH), 55.0 (C-5), 51.7 (OMe), 48.4 (C-18),
46.7 (Pro-δ-CH2), 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), 30.2 (Pro-β-CH2), 28.5 (C-
29), 28.3 (C-28), 28.1 (C-23), 26.5 (C-16), 26.4 (C-15), 25.2
(Pro-γ-CH2), 23.5 (C-2), 23.3 (C-27), 18.7 (C-26), 17.3 (C-
6), 16.7 (C-24), 16.4 (C-25). – MS (ESI): m/z (%) = 582.4
(100) [M+H]+. – C36H55NO5 (581.83): C 74.32, H 9.53, N
2.41; found C 74.11, H 9.75, N 2.28.
Obtained from 20 by method B as a colorless powder.
Yield: 200 mg, 66%. – M. p. 247 – 249 ◦C (decomp.). – Rf =
0.56 (dichloromethane-methanol, 9:1). – [α]D = 114.07 (c =
0.58, CHCl3). – UV/Vis (methanol): λmax(logε) = 249 nm
(4.05). – IR (KBr): ν = 3443br, 2951s, 2876m, 1732s, 1654s,
1619w, 1464m, 1388m, 1362m, 1324w, 1280m, 1215s,
1162s, 1086m, 1049w, 1021w, 989m cm−1. – 1H NMR
(500 MHz, CDCl3): δ = 5.66 (s, 1 H, 12-H), 4.61 (dd, 1 H,
J = 11.7, 4.8 Hz, 3-H), 3.69 (s, 3 H, OMe), 3.40 (s, 2 H,
Sar-CH2), 2.82 (ddd, 1 H, J = 13.7, 3.5, 3.5 Hz, 1-H), 2.49
(br, 1 H, NH), 2.47 (s, 3 H, NCH3), 2.36 (s, 1 H, 9-H), 2.08
(dd, 1 H, J = 14.0, 3.1 Hz, 18-H), 2.03 (ddd, 1 H, J = 13.7,
13.7, 4.5 Hz, 15-H), 1.99 (m, 1 H, 21-H), 1.93 (ddd, 1 H,
J = 13.6, 4.0, 2.6 Hz, 19-H), 1.80 (ddd, 1 H, J = 13.8, 13.8,
4.3 Hz, 16-H), 1.71 (m, 1 H, 2-H), 1.64 (m, 1 H, 7-H), 1.62
(m, 1 H, 20-H), 1.59 (dd, 1 H, J = 13.6, 13.6 Hz, 190-H),
1.55 (m, 1 H, 6-H), 1.45 (m, 1 H, 60-H), 1.42 (m, 1 H, 70-
H), 1.37 (m, 1 H, 22-H), 1.34 (s, 3 H, 27-H), 1.29 (m, 2 H,
220-H and 210-H), 1.16 (m, 1 H, 160-H), 1.14 (s, 3 H, 25-
H), 1.12 (s, 3 H, 29-H), 1.10 (s, 3 H, 26-H), 1.04 (ddd, 1 H,
J = 13.6, 13.6, 3.7 Hz, 10-H), 0.99 (m, 1 H, 150-H), 0.86 (s,
3 H, 24-H), 0.86 (s, 3 H, 23-H), 0.79 (m, 1 H, 5-H), 0.78 (s,
3 H, 28-H). – 13C NMR (125 MHz, CDCl3): δ = 200.0 (C-
11), 176.9 (C-30), 171.6 (Sar-COO), 169.2 (C-13), 128.5 (C-
12), 81.4 (C-3), 61.7 (C-9), 55.0 (C-5), 52.5 (Sar-CH2), 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), 38.1 (C-4), 37.7 (C-22), 36.9 (C-
10), 35.8 (NCH3), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21), 28.5
(C-28), 28.3 (C-29), 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). – MS (ESI): m/z (%) = 556.3 (100) [M+H]+,
578.3 (2) [M+Na]+, 833.9 (6) [3M+2H]2+. – C34H53NO5
(555.79): calcd. C 73.47, H 9.61, N, 2.52; found C 73.32, H
9.82, N 2.43.
Methyl (3β)-3-[(L)-phenylalanyloxy]-11-oxo-olean-12-en-
30-oate (8)
Obtained from 22 by method B as a colorless pow-
der. Yield: 460 mg, 98%. M. p.: 155 – 158 ◦C: Rf = 0.88
(dichloromethane-methanol, 9 : 1). – [α]D = 103.37 (c =
0.56, CHCl3). – UV/Vis (methanol): λmax(logε) = 249 nm
(3.96). – IR (KBr): ν = 3389br, 2952s, 2873m, 1731s, 1655s,
1618w, 1497w, 1455m, 1388m, 1368w, 1324w, 1286m,
1216s, 1180m, 1086w, 1022w cm−1. – 1H NMR (500 MHz,
CDCl3): δ = 7.33–7.18 (br, 5 H, Phe-Ar), 5.67 (s, 1 H, 12-
H), 4.56 (dd, 1 H, J = 11.5, 4.9 Hz, 3-H), 3.82 (dd, 1 H,
J = 7.8, 5.7 Hz, Phe-α-CH), 3.69 (s, 3 H, OMe), 3.19 (dd, 1
H, J = 13.7, 5.4 Hz, Phe-β-CHH0), 2.91 (dd, 1 H, J = 13.7,
8.0 Hz, Phe-β-CHH0), 2.81 (ddd, 1 H, J = 13.8, 3.7, 3.7 Hz,
1-H), 2.36 (s, 1 H, 9-H), 2.18 (br, 2 H, Phe-NH2), 2.09 (dd,
1 H, J = 13.1, 3.5 Hz, 18-H), 2.03 (m, 1 H, 15-H), 2.00 (m,
Methyl (3β)-3-[(L)-prolyloxy]-11-oxo-olean-12-en-30-oate
(7)
Obtained from 21 by method B as a colorless powder. 1 H, 21-H), 1.93 (m, 1 H, 19-H), 1.83 (ddd, 1 H, J = 13.4,
Yield: 130 mg, 92%. – M. p. 249 – 252 ◦C (decomp.). – Rf = 13.4, 4.7 Hz, 16-H), 1.70 (m, 1 H, 2-H), 1.66 (m, 1 H, 7-H),
0.52 (dichloromethane-methanol, 9 : 1). – [α]D = 105.45 1.63 (m, 1 H, 20-H), 1.61 (dd, 1 H, J = 13.6, 13.6 Hz, 190-
(c = 0.34, CHCl3). – UV/Vis (methanol): λmax(logε) = H), 1.57 (m, 1 H, 6-H), 1.44 (m, 1 H, 60-H), 1.42 (m, 1 H,
267 nm (4.11). – IR (KBr): ν = 3439br, 2958s, 2873m, 70-H), 1.39 (m, 1 H, 22-H), 1.37 (s, 3 H, 27-H), 1.31 (m, 2
1729s, 1656s, 1618w, 1464m, 1388m, 1355m, 1326m, H, 220-H and 210-H), 1.18 (m, 1 H, 160-H), 1.16 (s, 3 H, 25-
1278w, 1218s, 1160m, 1087m, 1049w, 1021w, 988m cm−1
.
H), 1.15 (s, 3 H, 29-H), 1.13 (s, 3 H, 26-H), 1.05 (m, 1 H,
– 1H NMR (500 MHz, CDCl3): δ = 5.66 (s, 1 H, 12-H), 4.58 1-H0), 1.02 (m, 1 H, 15-H0), 0.85 (s, 3 H, 24-H), 0.81 (s, 3 H,
(dd, 1 H, J = 11.8, 4.7 Hz, 3-H), 3.85 (dd, 1 H, J = 8.2, 23-H), 0.81 (s, 3 H, 28-H), 0.79 (m, 1 H, 5-H). – 13C NMR
5.9 Hz, Pro-α-CH), 3.69 (s, 3 H, OMe), 3.18 (br, 2 H, Pro- (125 MHz, CDCl3): δ = 199.9 (C-11), 176.9 (C-30), 173.8
NH2), 3.13 (dt, 1 H, J = 10.4, 6.8 Hz, Pro-δ-CHH0), 2.99 (Phe-COO), 169.2 (C-13), 136.8 (Phe-γ-C), 129.4 (Phe-Ar),
(dt, 1 H, J = 10.4, 6.7 Hz, Pro-δ-CHH0), 2.82 (ddd, 1 H, 128.7 (C-12), 128.5 (Phe-Ar), 126.9 (Phe-Ar), 81.9 (C-3),
J = 13.7, 3.4, 3.4 Hz, 1-H), 2.36 (s, 1 H, 9-H), 2.20 (m, 1 61.7 (C-9), 55.9 (Phe-α-CH), 55.0 (C-5), 51.7 (OMe), 48.4
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R. Csuk et al. · Methyl Glycyrrhetinate Esterified with Amino Acids
(C-18), 45.4 (C-8), 44.0 (C-20), 43.2 (C-14), 41.1 (C-19), (3.92). – IR (KBr): ν = 3390br, 2960s, 2873m, 1729s, 1653s,
40.4 (Phe-β-CH2), 38.7 (C-1), 38.1 (C-4), 37.7 (C-22), 36.9 1466m, 1389m, 1318w, 1277m, 1246m, 1218m, 1154m,
(C-10), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21), 28.5 (C-28), 1087w, 1022w, 987m cm−1. – 1H NMR (500 MHz, CDCl3):
28.3 (C-29), 28.1 (C-23), 26.5 (C-16), 26.4 (C-15), 23.5 (C- δ = 5.66 (s, 1 H, 12-H), 4.57 (dd, 1 H, J = 11.4, 5.0 Hz, 3-
2), 23.3 (C-27), 18.7 (C-26), 17.3 (C-6), 16.7 (C-24), 16.3 H), 3.33 (d, 1 H, J = 4.4 Hz, Val-α-CH), 3.69 (s, 3 H, OMe),
(C-25). – MS (ESI): m/z (%) = 632.3 (100) [M+H]+, 948.3 2.81 (ddd, 1 H, J = 13.7, 3.5, 3.5 Hz, 1-H), 2.36 (s, 1 H, 9-
(6) [3M+2H]2+. – C40H57NO5 (631.88): C 76.03, H 9.09, H), 2.12 (m, 1 H, Val-β-CH), 2.08 (m, 1 H, 18-H), 2.03 (m,
N 2.22; found C 75.83, H 9.24, N 2.10.
1 H, 15-H), 1.99 (m, 1 H, 21-H), 1.93 (ddd, 1 H, J = 13.6,
3.6, 2.7 Hz, 19-H), 1.84 (m, 1 H, 16-H), 1.72 (m, 1 H, 2-
H), 1.67 (m, 1 H, 7-H), 1.64 (m, 1 H, 20-H), 1.61 (dd, 1 H,
J = 13.6, 13.6 Hz, 190-H), 1.58 (m, 1 H, 6-H), 1.47 (m, 1
H, 60-H), 1.42 (m, 1 H, 70-H), 1.39 (m, 1 H, 22-H), 1.37 (s,
3 H, 27-H), 1.31 (m, 2 H, 220-H and 210-H), 1.18 (m, 1 H,
160-H), 1.17 (s, 3 H, 25-H), 1.15 (s, 3 H, 29-H), 1.13 (s, 3
H, 26-H), 1.06 (m, 1 H, 1-H0), 1.02 (m, 1 H, 15-H0), 1.02
(d, 3 H, J = 6.7 Hz, Val-CH3), 0.90 (m, 3 H, Val-CH3), 0.90
(s, 3 H, 24-H), 0.90 (s, 3 H, 23-H), 0.82 (m, 1 H, 5-H), 0.80
(s, 3 H, 28-H). – 13C NMR (125 MHz, CDCl3): δ = 200.0
(C-11), 176.9 (C-30), 174.8 (Val-COO), 169.2 (C-13), 128.5
(C-12), 81.4 (C-3), 61.7 (C-9), 60.2 (Val-α-CH), 55.1 (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), 38.7 (C-1), 38.1 (C-4), 37.7 (C-22), 36.9
(C-10), 32.7 (C-7), 31.8 (C-17), 31.7 (Val-β-CH), 31.1 (C-
21), 28.5 (C-28), 28.3 (C-29), 28.2 (C-23), 26.5 (C-16), 26.4
(C-15), 23.6 (C-2), 23.3 (C-27), 19.6 (Val-CH3), 18.7 (C-
26), 17.4 (C-6), 16.9 (Val-CH3), 16.8 (C-24), 16.4 (C-25). –
MS (ESI): m/z (%) = 584.3 (100) [M+H]+. – C36H57NO5
(583.84): C 74.06, H 9.84, N 2.40; found C 73.87, H 9.94, N
2.23.
Methyl (3β)-3-[(L)-methionyloxy]-11-oxo-olean-12-en-
30-oate (9)
Obtained from 23 by method B as a colorless pow-
der. Yield: 210 mg, 90%. M. p.: 239 – 242 ◦C. – Rf = 0.77
(dichloromethane-methanol, 9 : 1). – [α]D = 110.17 (c =
0.23, CHCl3). – UV/Vis (methanol): λmax(logε) = 268 nm
(4.09). – IR (KBr): ν = 3374br, 2958s, 2928m, 2872m,
1727s, 1651s, 1466w, 1389w, 1363w, 1324w, 1279w, 1248w,
1217m, 1182m, 1154m, 1086w, 1050w, 1022w cm−1. – 1H
NMR (500 MHz, CDCl3): δ = 5.67 (s, 1 H, 12-H), 4.58 (dd,
1 H, 3-H, J = 11.7, 4.8 Hz), 3.69 (m, 1 H, Met-α-CH), 3.69
(s, 3 H, OMe), 2.83 (ddd, 1 H, J = 13.7, 3.5, 3.5 Hz, 1-H),
2.67 (dd, 2 H, J = 7.4, 7.4 Hz, Met-β-CH2), 2.36 (s, 1 H,
9-H), 2.13 (m, 1 H, Met-γ-CHH0), 2.12 (s, 3 H, Met-CH3),
2.09 (m, 1 H, 18-H), 2.03 (m, 1 H, 15-H), 1.99 (m, 1 H, 21-
H), 1.93 (ddd, 1 H, J = 13.7, 4.0, 2.3 Hz, 19-H), 1.86 (m,
1 H, Met-γ-CHH0), 1.83 (m, 1 H, 16-H), 1.74 (m, 1 H, 2-
H), 1.67 (m, 1 H, 7-H), 1.64 (m, 1 H, 20-H), 1.61 (dd, 1 H,
J = 13.6, 13.6 Hz, 190-H), 1.57 (m, 1 H, 6-H), 1.47 (m, 1
H, 60-H), 1.42 (m, 1 H, 70-H), 1.39 (m, 1 H, 22-H), 1.37 (s,
3 H, 27-H), 1.31 (m, 2 H, 220-H and 210-H), 1.19 (m, 1 H,
160-H), 1.17 (s, 3 H, 25-H), 1.15 (s, 3 H, 29-H), 1.13 (s, 3 H,
26-H), 1.06 (ddd, 1 H, J = 13.8, 13.8, 3.6 Hz, 1-H0), 1.02 (m,
1 H, 15-H0), 0.90 (s, 3 H, 24-H), 0.89 (s, 3 H, 23-H), 0.82
(m, 1 H, 5-H), 0.81 (s, 3 H, 28-H). – 13C NMR (125 MHz,
CDCl3): δ = 199.9 (C-11), 176.9 (C-30), 174.4 (Met-COO),
169.2 (C-13), 128.5 (C-12), 81.9 (C-3), 61.7 (C-9), 55.0 (C-
5), 53.5 (Met-α-CH), 51.8 (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), 38.2 (C-
4), 37.7 (C-22), 36.9 (C-10), 33.3 (Met-γ-CH2), 32.7 (C-7),
31.8 (C-17), 31.1 (C-21), 30.4 (Met-β-CH2), 28.5 (C-28),
28.3 (C-29), 28.2 (C-23), 26.5 (C-16), 26.4 (C-15), 23.6 (C-
2), 23.4 (C-27), 18.7 (C-26), 17.4 (C-6), 16.8 (C-24), 16.4
(C-25), 15.3 (Met-CH3). – MS (ESI): m/z (%) = 616.3 (100)
[M+H]+, 638.4 (4) [M+Na]+. – C36H57NO5S (615.91): C
70.20, H 9.33, N 2.27; found C 69.98, H 9.53, N 2.17.
Methyl (3β)-3-[(L)-isoleucyloxy]-11-oxo-olean-12-en-
30-oate (11)
Obtained from 25 by method B as a colorless pow-
der. Yield: 30 mg, 32%. M. p.: 244 – 247 ◦C. – Rf = 0.65
(dichloromethane-methanol, 9 : 1). – [α]D = 124.45 (c =
0.36, MeOH). – UV/Vis (methanol): λmax(logε) = 267 nm
(4.04). – IR (KBr): ν = 3392br, 2962s, 2875s, 1729s, 1653s,
1616m, 1465m, 1389m, 1362m, 1318m, 1278m, 1260m,
1235m, 1218s, 1154m, 1087m, 1051w, 1022w, 986m cm−1
.
– 1H NMR (500 MHz, CDCl3): δ = 5.66 (s, 1 H, 12-H), 4.56
(dd, 1 H, J = 11.3, 5.1 Hz, 3-H), 3.68 (s, 3 H, OMe), 3.36
(d, 1 H, J = 4.5 Hz, Ile-α-CH), 2.81 (ddd, 1 H, J = 13.7,
3.5, 3.5 Hz, 1-H), 2.36 (s, 1 H, 9-H), 2.08 (dd, 1 H, J = 14.1,
3.4 Hz, 18-H), 2.03 (m, 1 H, 15-H), 1.99 (m, 1 H, 21-H), 1.92
(ddd, 1 H, J = 13.3, 3.9, 2.7 Hz, 19-H), 1.83 (m, 1 H, Ile-β-
CH), 1.81 (m, 1 H, 16-H), 1.71 (m, 1 H, 2-H), 1.66 (m, 1 H,
7-H), 1.64 (m, 1 H, 20-H), 1.61 (dd, 1 H, J = 13.6, 13.6 Hz,
190-H), 1.58 (m, 1 H, 6-H), 1.47 (m, 1 H, 60-H), 1.42 (m, 2
Methyl (3β)-3-[(L)-valyloxy]-11-oxo-olean-12-en-
30-oate (10)
Obtained from 24 by method B as a colorless pow- H, Ile-γ-CH2), 1.41 (m, 1 H, 70-H), 1.39 (m, 1 H, 22-H), 1.36
der. Yield: 240 mg, 94%. M. p.: 248 – 250 ◦C. – Rf = 0.68 (s, 3 H, 27-H), 1.31 (m, 2 H, 220-H and 210-H), 1.18 (m, 1 H,
(dichloromethane-methanol, 9 : 1). – [α]D = 130.46 (c = 160-H), 1.17 (s, 3 H, 25-H), 1.15 (s, 3 H, 29-H), 1.13 (s, 3
0.10, CHCl3). – UV/Vis (methanol): λmax(logε) = 267 nm H, 26-H), 1.06 (m, 1 H, 1-H0), 1.01 (m, 1 H, 15-H0), 0.99 (d,
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R. Csuk et al. · Methyl Glycyrrhetinate Esterified with Amino Acids
737
3 H, J = 6.8 Hz, Ile-β-CH3), 0.91 (t, 3 H, J = 7.4 Hz, Ile-γ- Methyl (3β)-3-[(4-aminobutanoyl)oxy]-11-oxoolean-12-en-
CH3), 0.90 (s, 3 H, 24-H), 0.89 (s, 3 H, 23-H), 0.82 (m, 1 H, 30-oate (13)
5-H), 0.80 (s, 3 H, 28-H). – 13C NMR (125 MHz, CDCl3):
Obtained from 27 by method B as a colorless pow-
δ = 200.0 (C-11), 176.9 (C-30), 175.1 (Ile-COO), 169.2 (C-
der. Yield: 320 mg, 93%. M. p.: 255 – 259 ◦C. – Rf =
13), 128.5 (C-12), 81.3 (C-3), 61.7 (C-9), 59.8 (Ile-α-CH),
0.12 (dichloromethane-methanol, 9 : 1). – [α]D = 109.54
55.1 (C-5), 51.7 (OMe), 48.4 (C-18), 45.4 (C-8), 44.0 (C-
(c = 0.43, CHCl3). – UV/Vis (methanol): λmax(logε) =
20), 43.2 (C-14), 41.1 (C-19), 38.7 (Ile-β-CH), 38.7 (C-1),
250 nm (4.07). – IR (KBr): ν = 3438br, 2951s, 1729s, 1654s,
38.0 (C-4), 37.7 (C-22), 36.9 (C-10), 32.7 (C-7), 31.8 (C-
1465s, 1388s, 1324m, 1280m, 1256m, 1213s, 1166s, 1086m,
17), 31.1 (C-21), 28.5 (C-28), 28.3 (C-29), 28.1 (C-23), 26.4
1022m, 987m cm−1. – 1H NMR (500 MHz, CDCl3): δ =
5.66 (s, 1 H, 12-H), 4.53 (dd, 1 H, J = 11.6, 4.8 Hz, 3-H),
(C-16), 26.4 (C-15), 24.3 (Ile-γ-CH2), 23.6 (C-2), 23.3 (C-
27), 18.7 (C-26), 17.3 (C-6), 16.9 (C-24), 16.3 (C-25), 15.9
3.69 (s, 3 H, OMe), 3.18 (br, 1 H, chain-NH2), 2.87 (t, 2
(Ile-β-CH3), 11.7 (Ile-γ-CH3). – MS (ESI): m/z (%) = 598.2
H, J = 7.1 Hz, chain-γ-CH2), 2.80 (ddd, 1 H, J = 13.6, 3.4,
(100) [M+H]+. – C37H59NO5 (597.87): C 74.33, H 9.95, N
3.4 Hz, 1-H), 2.42 (t, 2 H, J = 7.4 Hz, chain-α-CH2), 2.36 (s,
1 H, 9-H), 2.08 (dd, 1 H, J = 13.8, 3.4 Hz, 18-H), 2.03 (m,
2.34; found C 74.13, H 10.03, N 2.27.
1 H, 15-H), 1.99 (m, 1 H, 21-H), 1.93 (m, 1 H, 19-H), 1.88
Methyl (3β)-3-[(L)-leucyloxy]-11-oxo-olean-12-en-30-oate
(m, 2 H, chain-β-CH2), 1.82 (m, 1 H, 16-H), 1.71 (m, 1 H,
(12)
2-H), 1.66 (m, 1 H, 7-H), 1.63 (m, 1 H, 20-H), 1.61 (dd, 1 H,
J = 13.5, 13.5 Hz, 190-H), 1.58 (m, 1 H, 6-H), 1.48 (m, 1 H,
Obtained from 26 by method B as a colorless pow-
der. Yield: 290 mg, 98%. M. p.: 234 – 236 ◦C. – Rf = 0.69
(dichloromethane-methanol, 9 : 1). – [α]D = 127.03 (c =
0.28, CHCl3). – UV/Vis (methanol): λmax(logε) = 267 nm
(4.01). – IR (KBr): ν = 3406br, 2957s, 2873m, 2361w,
1728s, 1652s, 1464m, 1388m, 1324w, 1261m, 1212m,
1190m, 1168m, 1086w, 1021w cm−1. – 1H NMR (500 MHz,
CDCl3): δ = 5.66 (s, 1 H, 12-H), 4.56 (dd, 1 H, J = 11.6,
4.8 Hz, 3-H), 3.69 (s, 3 H, OMe), 3.49 (dd, 1 H, J = 8.6,
5.4 Hz, Leu-α-CH), 2.82 (ddd, 1 H, J = 13.7, 3.5, 3.5 Hz,
1-H), 2.36 (s, 1 H, 9-H), 2.15 (br, 2 H, Leu-NH2), 2.08 (m,
1 H, 18-H), 2.03 (m, 1 H, 15-H), 1.99 (m, 1 H, 21-H), 1.93
(ddd, 1 H, J = 13.6, 3.4, 2.6 Hz, 19-H), 1.84 (m, 1 H, 16-H),
1.81 (m, 1 H, Leu-γ-CH), 1.72 (m, 1 H, 2-H), 1.65 (m, 1 H,
7-H), 1.61 (dd, 1 H, J = 13.3, 13.3 Hz, 190-H), 1.60 (m, 1
H, 20-H), 1.59 (m, 1 H, Leu-β-CHH0), 1.57 (m, 1 H, 6-H),
1.48 (m, 1 H, Leu-β-CHH0), 1.44 (m, 1 H, 60-H), 1.41 (m, 1
H, 70-H), 1.39 (m, 1 H, 22-H), 1.37 (s, 3 H, 27-H), 1.31 (m,
2 H, 220-H and 210-H), 1.19 (m, 1 H, 160-H), 1.17 (s, 3 H,
25-H), 1.15 (s, 3 H, 29-H), 1.13 (s, 3 H, 26-H), 1.06 (ddd, 1
H, J = 13.6, 13.6, 3.7 Hz, 1-H0), 1.02 (m, 1 H, 15-H0), 0.96
(d, 3 H, J = 6.4 Hz, Leu-γ-CH3), 0.94 (d, 3 H, J = 6.4 Hz,
Leu-γ-CH3), 0.90 (s, 3 H, 24-H), 0.89 (s, 3 H, 23-H), 0.82
60-H), 1.42 (m, 1 H, 70-H), 1.38 (m, 1 H, 22-H), 1.37 (s, 3 H,
27-H), 1.31 (m, 2 H, 220-H and 210-H), 1.18 (m, 1 H, 160-H),
1.16 (s, 3 H, 25-H), 1.15 (s, 3 H, 29-H), 1.13 (s, 3 H, 26-H),
1.05 (m, 1 H, 1-H0), 1.02 (m, 1 H, 15-H0), 0.88 (s, 3 H, 24-H),
0.87 (s, 3 H, 23-H), 0.81 (s, 3 H, 28-H), 0.80 (m, 1 H, 5-H). –
13C NMR (125 MHz, CDCl3): δ = 199.8 (C-11), 176.7 (C-
30), 172.8 (chain-COO), 169.0 (C-13), 128.3 (C-12), 80.7
(C-3), 61.5 (C-9), 54.8 (C-5), 51.6 (OMe), 48.2 (C-18), 45.2
(C-8), 43.8 (C-20), 43.0 (C-14), 40.9 (C-19), 40.6 (chain-
γ-CH2), 38.6 (C-1), 37.9 (C-4), 37.5 (C-22), 36.7 (C-10),
32.5 (C-7), 31.8 (chain-α-CH2), 31.6 (C-17), 30.9 (C-21),
28.3 (C-28), 28.1 (C-29), 27.9 (C-23), 26.7 (chain-β-CH2),
26.3 (C-16), 26.2 (C-15), 23.4 (C-2), 23.2 (C-27), 18.5 (C-
26), 17.2 (C-6), 16.6 (C-24), 16.2 (C-25). – MS (ESI): m/z
(%) = 570.4 (100) [M+H]+, 592.3 (2) [M+Na]+, 855.4 (10)
[3M+2H]2+, 903.3 (16) [3M+2H+3MeOH]2+, 1139.2 (6)
[2M+H]+. – C35H55NO5 (569.81): C 73.77, H 9.73, N 2.46;
found C 73.62, H 9.91, N 2.33.
Methyl (3β)-3-[(5-aminopentanoyl)oxy]-11-oxoolean-
12-en-30-oate (14)
Obtained from 28 by method B as a colorless pow-
(m, 1 H, 5-H), 0.80 (s, 3 H, 29-H). – 13C NMR (125 MHz, der. Yield: 300 mg, 95%. M. p.: 231 – 235 ◦C. – Rf =
CDCl3): δ = 200.0 (C-11), 176.9 (C-30), 175.9 (Leu-COO), 0.17 (dichloromethane-methanol, 9 : 1). – [α]D = 106.11
169.2 (C-13), 128.5 (C-12), 81.2 (C-3), 61.7 (C-9), 55.0 (C- (c = 0.53, CHCl3). – UV/Vis (methanol): λmax(logε) =
5), 53.2 (Leu-α-CH), 51.8 (OMe), 48.4 (C-18), 45.4 (C-8), 248 nm (4.06). – IR (KBr): ν = 3438br, 2951s, 1730s, 1662s,
44.0 (C-20), 43.9 (Leu-β-CH2), 43.2 (C-14), 41.1 (C-19), 1535w, 1464m, 1432w, 1387m, 1323w, 1258m, 1206s,
38.7 (C-1), 38.2 (C-4), 37.7 (C-22), 36.9 (C-10), 32.7 (C- 1139s, 1087w, 1023w cm−1. – 1H NMR (500 MHz, CDCl3):
7), 31.8 (C-17), 31.1 (C-21), 28.5 (C-28), 28.3 (C-29), 28.2 δ = 6.22 (br, 2 H, chain-NH2), 5.66 (s, 1 H, 12-H), 4.50 (dd,
(C-23), 26.5 (C-16), 26.4 (C-15), 24.8 (Leu-γ-CH), 23.6 (C- 1 H, J = 11.7, 4.7 Hz, 3-H), 3.69 (s, 3 H, OMe), 2.94 (t, 2
2), 23.3 (C-27), 23.0 (Leu-γ-CH3), 21.8 (Leu-γ-CH3), 18.7 H, J = 6.0 Hz, chain-δ-CH2), 2.80 (ddd, 1 H, J = 13.6, 3.6,
(C-26), 17.4 (C-6), 16.8 (C-24), 16.4 (C-25). – MS (ESI): 3.6 Hz, 1-H), 2.37 (s, 1 H, 9-H), 2.35 (t, 2 H, J = 6.4 Hz,
m/z (%) = 598.3 (100) [M+H]+. – C37H59NO5 (597.87): C chain-α-CH2), 2.09 (dd, 1 H, J = 13.8, 4.0 Hz, 18-H), 2.03
74.33, H 9.95, N 2.34; found C 74.24, H 10.15, N 2.08.
(m, 1 H, 15-H), 1.99 (m, 1 H, 21-H), 1.93 (ddd, 1 H, J = 13.7,
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738
R. Csuk et al. · Methyl Glycyrrhetinate Esterified with Amino Acids
3.4, 2.2 Hz, 19-H), 1.82 (ddd, 1 H, J = 13.3, 13.3, 4.0 Hz, 16- CH2), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21), 30.4 (chain-δ-
H), 1.72 (m, 1 H, 2-H), 1.70 (m, 2 H, chain-β-CH2), 1.70 (m, CH2), 28.5 (C-28), 28.3 (C-29), 28.1 (C-23), 26.4 (C-16),
2 H, chain-γ-CH2), 1.66 (m, 1 H, 7-H), 1.63 (m, 1 H, 20-H), 26.4 (C-15), 26.1 (chain-β-CH2), 24.6 (chain-γ-CH2), 23.6
1.61 (dd, 1 H, J = 13.6, 13.6 Hz, 190-H), 1.59 (m, 1 H, 6-H), (C-2), 23.3 (C-27), 18.7 (C-26), 17.4 (C-6), 16.7 (C-24), 16.4
1.46 (m, 1 H, 60-H), 1.40 (m, 1 H, 70-H), 1.38 (m, 1 H, 22-H), (C-25). – MS (ESI): m/z (%) = 598.4 (100) [M+H]+, 944.9
1.37 (s, 3 H, 27-H), 1.31 (m, 2 H, 220-H and 210-H), 1.19 (m, (4) [3M+2H+3MeOH]2+. – C37H59NO5 (597.87): C 74.33,
1 H, 160-H), 1.16 (s, 3 H, 25-H), 1.15 (s, 3 H, 29-H), 1.12 (s, 3 H 9.95, N 2.34; found C 74.26, H 10.12, N 2.15.
H, 26-H), 1.07 (m, 1 H, 1-H0), 1.02 (m, 1 H, 15-H0), 0.87 (s, 3
Methyl (3β)-3-[(6-aminooctanoyl)oxy]-11-oxoolean-
12-en-30-oate (16)
H, 24-H), 0.86 (s, 3 H, 23-H), 0.81 (s, 3 H, 28-H), 0.79 (m, 1
H, 5-H). – 13C NMR (125 MHz, CDCl3): δ = 200.1 (C-11),
176.9 (C-30), 173.2 (chain-COO), 169.4 (C-13), 128.5 (C-
12), 81.1 (C-3), 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), 39.5
(chain-δ-CH2), 38.7 (C-1), 38.0 (C-4), 37.8 (C-22), 36.9 (C-
10), 33.8 (chain-α-CH2), 32.7 (C-7), 31.8 (C-17), 31.1 (C-
21), 28.5 (C-28), 28.3 (C-29), 28.0 (C-23), 27.3 (chain-γ-
CH2), 26.5 (C-16), 26.4 (C-15), 23.5 (C-2), 23.3 (C-27), 21.8
(chain-β-CH2), 18.7 (C-26), 17.4 (C-6), 16.7 (C-24), 16.4
(C-25). – MS (ESI): m/z (%) = 584.4 (100) [M+H]+, 606.4
(2) [M+Na]+, 876.0 (1) [2M+2H]2+, 1167.2 (2) [2M+H]+.
– C36H57NO5 (583.84): C 74.06, H 9.84, N 2.40; found C
73.95, H 2.69, N 2.25.
Obtained from 30 by method B as a colorless powder.
Yield: 310 mg, 97%. M. p.: 190 – 193 ◦C (decomp.). – Rf =
0.25 (dichloromethane-methanol, 9 : 1). – [α]D = 102.65
(c = 0.56, CHCl3). – UV/Vis (methanol): λmax(logε) =
249 nm (4.07). – IR (KBr): ν = 3437br, 2933s, 2875s, 1730s,
1660s, 1465s, 1388m, 1364m, 1323m, 1280m, 1250m,
1217s, 1154s, 1086m, 1049w, 1023w, 987m cm−1. – 1H
NMR (500 MHz, CDCl3): δ = 5.66 (s, 1 H, 12-H), 4.52 (dd,
1 H, J = 11.7, 4.7 Hz, 3-H), 3.69 (s, 3 H, OMe), 2.80 (m, 1
H, 1-H), 2.78 (m, 2 H, chain-η-CH2), 2.44 (br, 1 H, chain-
NH2), 2.36 (s, 1 H, 9-H), 2.29 (t, 2 H, J = 7.4 Hz, chain-
α-CH2), 2.08 (dd, 1 H, J = 14.0, 4.1 Hz, 18-H), 2.03 (ddd,
1 H, J = 13.5, 13.5, 4.4 Hz, 15-H), 1.99 (m, 1 H, 21-H),
1.92 (ddd, 1 H, J = 13.6, 3.9, 2.7 Hz, 19-H), 1.82 (ddd, 1
H, J = 13.6, 13.6, 4.4 Hz, 16-H), 1.69 (m, 1 H, 2-H), 1.66
(m, 1 H, 7-H), 1.63 (m, 1 H, 20-H), 1.62 (m, 2 H, chain-β-
CH2), 1.61 (dd, 1 H, J = 13.5, 13.5 Hz, 190-H), 1.56 (m, 1
H, 6-H), 1.47 (m, 1 H, 60-H), 1.43 (m, 2 H, chain-ζ-CH2),
1.41 (m, 1 H, 70-H), 1.39 (m, 1 H, 22-H), 1.36 (s, 3 H, 27-H),
1.33 (m, 6 H, chain-δ-CH2 and chain-γ-CH2, chain-ε-CH2),
1.31 (m, 2 H, 220-H and 210-H), 1.18 (m, 1 H, 160-H), 1.16
(s, 3 H, 25-H), 1.15 (s, 3 H, 29-H), 1.12 (s, 3 H, 26-H), 1.05
(ddd, 1 H, J = 13.6, 13.6, 3.8 Hz, 1-H0), 1.01 (m, 1 H, 15-
H0), 0.88 (s, 3 H, 24-H), 0.87 (s, 3 H, 23-H), 0.80 (s, 3 H,
28-H), 0.80 (m, 1 H, 5-H). – 13C NMR (125 MHz, CDCl3):
δ = 200.8 (C-11), 176.9 (C-30), 173.6 (chain-COO), 169.2
(C-13), 128.5 (C-12), 80.3 (C-3), 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),
41.3 (chain-η-CH2), 41.1 (C-19), 38.8 (C-1), 38.1 (C-4),
37.7 (C-22), 36.9 (C-10), 34.7 (chain-α-CH2), 32.7 (C-7),
31.8 (C-17), 31.4 (chain-ζ-CH2), 31.1 (C-21), 29.0 (chain-
δ-CH2), 28.9 (chain-γ-CH2), 28.5 (C-28), 28.3 (C-29), 28.1
(C-23), 26.5 (chain-ε-CH2), 26.5 (C-16), 26.4 (C-15), 25.0
(chain-β-CH2), 23.6 (C-2), 23.3 (C-27), 18.7 (C-26), 17.4
(C-6), 16.8 (C-24), 16.4 (C-25). – MS (ESI): m/z (%) =
626.5 (100) [M+H]+. – C39H63NO5 (625.92): C 74.84, H
10.15, N 2.24; found C 74.75, H 10.23, N 2.02.
Methyl (3β)-3-[(6-aminohexanoyl)oxy]-11-oxoolean-12-
en-30-oate (15)
Obtained from 29 by method B as a colorless pow-
der. Yield: 90 mg, 58%. M. p.: 254 – 257 ◦C. – Rf = 0.16
(dichloromethane-methanol, 9 : 1). – [α]D = 100.55 (c =
0.25, CHCl3). – UV/Vis (methanol): λmax(logε) = 250 nm
(4.06). – IR (KBr): ν = 3433br, 2950s, 1730s, 1655s, 1465m,
1388w, 1323w, 1258w, 1212m, 1087w cm−1. – 1H NMR
(500 MHz, CDCl3): δ = 5.66 (s, 1 H, 12-H), 4.51 (dd, 1 H,
J = 11.7, 4.4 Hz, 3-H), 3.69 (s, 3 H, OMe), 3.21 (br, 2 H,
chain-NH2), 2.79 (m, 2 H, chain-ε-CH2), 2.78 (m, 1 H, 1-
H), 2.36 (s, 1 H, 9-H), 2.31 (m, 2 H, chain-α-CH2), 2.08 (dd,
1 H, J = 13.9, 3.7 Hz, 18-H), 2.02 (m, 1 H, 15-H), 1.99 (m,
1 H, 21-H), 1.92 (m 1 H, 19-H), 1.82 (ddd, 1 H, J = 13.7,
13.7, 4.3 Hz, 16-H), 1.69 (m, 1 H, 2-H), 1.68 (m, 1 H, 7-H),
1.64 (m, 2 H, chain-β-CH2), 1.62 (m, 1 H, 20-H), 1.61 (dd,
1 H, J = 13.6, 13.6 Hz, 190-H), 1.58 (m, 2 H, chain-δ-CH2),
1.55 (m, 1 H, 6-H), 1.44 (m, 1 H, 60-H), 1.41 (m, 1 H, 70-
H), 1.40 (m, 1 H, 22-H), 1.38 (m, 2 H, chain-β-CH2), 1.36
(s, 3 H, 27-H), 1.31 (m, 2 H, 220-H and 210-H), 1.18 (m, 1
H, 160-H), 1.16 (s, 3 H, 25-H), 1.15 (s, 3 H, 29-H), 1.12 (s,
3 H, 26-H), 1.05 (ddd, 1 H, J = 13.6, 13.6, 3.7 Hz, 1-H0),
1.01 (m, 1 H, 15-H0), 0.88 (s, 3 H, 24-H), 0.87 (s, 3 H, 23-
H), 0.80 (s, 3 H, 28-H), 0.80 (m, 1 H, 5-H). – 13C NMR
(125 MHz, CDCl3): δ = 200.0 (C-11), 176.9 (C-30), 173.4
(chain-COO), 169.2 (C-13), 128.5 (C-12), 80.5 (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), 40.8 (chain-ε-CH2), 38.7
Methyl (3β)-3-[(2,4-diaminobutanoyl)oxy]-11-oxoolean-
12-en-30-oate dihydrochloride (17)
Obtained from 31 by method C as a colorless powder.
(C-1), 38.1 (C-4), 37.7 (C-22), 36.9 (C-10), 34.5 (chain-α- Yield: 160 mg, 52%. M. p.: > 300 ◦C (decomp.). – Rf =
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R. Csuk et al. · Methyl Glycyrrhetinate Esterified with Amino Acids
739
0.02 (methanol-triethylamine, 95 : 5). – [α]D = 117.45 (c = H), 1.07 (m, 1 H, 1-H0), 1.02 (m, 1 H, 15-H0), 0.90 (s, 3 H,
0.47, MeOH). – UV/Vis (methanol): λmax(logε) = 249 nm 24-H), 0.89 (s, 3 H, 23-H), 0.82 (m, 1 H, 5-H), 0.81 (s, 3 H,
(3.99). – IR (KBr): ν = 3438br, 2950s, 1729s, 1659s, 1466m, 28-H). – 13C NMR (125 MHz, CDCl3): δ = 200.2 (C-11),
1387m, 1323m, 1218s, 1153s, 1085m, 989m, 948m cm−1. – 176.9 (C-30), 174.9 (Orn-COO), 169.1 (C-13), 128.5 (C-12),
1H NMR (500 MHz, CDCl3): δ = 5.44 (s, 1 H, 12-H), 4.60 78.7 (C-3), 61.8 (C-9), 54.9 (C-5), 53.7 (Orn-α-CH), 51.7
(dd, 1 H, J = 12.1, 5.1 Hz, 3-H), 4.24 (dd, 1 H, J = 7.8, (OMe), 48.4 (C-18), 45.4 (C-8), 44.0 (C-20), 43.2 (C-14),
5.5 Hz, Dab-α-CH), 3.63 (s, 3 H, OMe), 3.02 (m, 2 H, Dab- 41.7 (Orn-δ-CH2), 41.1 (C-19), 39.1 (C-1), 38.1 (C-4), 37.7
γ-CH2), 2.67 (ddd, 1 H, J = 13.3, 3.5, 3.5 Hz, 1-H), 2.43 (C-22), 36.9 (C-10), 29.8 (Orn-β-CH2), 32.7 (C-7), 31.8 (C-
(s, 1 H, 9-H), 2.25 (m, 1 H, Dab-β-CHH0), 2.18 (m, 1 H, 17), 31.1 (C-21), 28.5 (C-29), 28.3 (C-28), 28.1 (C-23), 27.3
18-H), 2.10 (m, 1 H, Dab-β-CHH0), 2.08 (m, 1 H, 15-H), (Orn-γ-CH2), 26.5 (C-16), 26.4 (C-15), 23.6 (C-2), 23.4 (C-
2.01 (m, 1 H, 21-H), 1.83 (m, 1 H, 19-H), 1.86 – 1.61 (m, 27), 18.7 (C-26), 17.5 (C-6), 16.8 (C-24), 16.3 (C-25). – MS
5 H, 16-H, H-7, H-6, H-60, 70-H), 1.54 (m, 1 H, 2-H), 1.53 (ESI): m/z (%) = 599.5 (1100) [M+H]+. – C36H58N2O5
(m, 1 H, 20-H), 1.40 (m, 1 H, 22-H), 1.37 (s, 3 H, 27-H), (598.86): C 72.20, H 9.76, N 4.68; found C 72.01, H 9.90,
1.36 (m, 2 H, 220-H and 210-H), 1.15 (m, 1 H, 160-H), 1.08 N 4.55.
(s, 3 H, 25-H), 1.12 (m, 1 H, 1-H0), 1.11 (s, 3 H, 23-H),
1.06 (s, 3 H, 26-H), 0.94 (m, 1 H, 15-H0, 0.92 (m, 1 H, 5-
Methyl (3β)-3-[(L)-lysyloxy]-11-oxoolean-12-en-30-oate
H), 0.89 (s, 3 H, 24-H), 0.88 (s, 3 H, 28-H), 0.75 (s, 3 H,
29-H). – 13C NMR (125 MHz, CDCl3): δ = 199.4 (C-11),
176.7 (C-30), 170.1 (Dab-COO), 169.1 (C-13), 127.7 (C-
12), 83.1 (C-3), 61.2 (C-9), 53.9 (C-5), 52.1 (Dab-α-CH),
50.3 (OMe), 48.4 (C-18), 45.3 (C-8), 44.0 (C-20), 43.4 (C-
14), 40.6 (C-19), 39.4 (C-1), 38.2 (C-4), 37.8 (C-22), 36.9
(C-10), 35.8 (Dab-β-CH2), 32.3 (C-7), 32.0 (C-17), 30.8
(C-21), 28.7 (C-29), 28.4 (Dab-γ-CH2), 28.2 (C-28), 28.1
(C-23), 26.5 (C-16), 26.2 (C-15), 23.6 (C-2), 23.4 (C-27),
18.6 (C-26), 17.3 (C-6), 17.1 (C-24), 16.6 (C-25). – MS
(ESI): m/z (%) = 585.5 (100) [M+H]+. – C35H58Cl2N2O5
(657.75): C 63.91, H 8.89, N 4.26; found C 63.78, H 9.02,
N 4.13.
(19)
Obtained from 33 by method B as a colorless powder.
Yield: 240 mg, 87%. M. p.: 255 – 257 ◦C (decomp.). – Rf =
0.02 (dichloromethane-methanol, 9 : 1). – [α]D = 112.21
(c = 0.41, CHCl3). – UV/Vis (methanol): λmax(logε) =
267 nm (4.09). – IR (KBr): ν = 3432br, 2929s, 2858m,
1729s, 1653s, 1464m, 1388m, 1323w, 1260w, 1216m,
1188m, 1154m, 1087w, 1022w cm−1. – 1H NMR (500 MHz,
CDCl3): δ = 5.64 (s, 1 H, 12-H), 4.53 (dd, 1 H, J = 11.8,
4.7 Hz, 3-H), 3.66 (s, 3 H, OMe), 3.41 (m, 1 H, Lys-α-CH),
2.79 (ddd, 1 H, J = 13.7, 3.5, 3.5 Hz, 1-H), 3.69 (m, 2 H,
Lys-ε-CH2), 2.34 (s, 1 H, 9-H), 2.05 (m, 1 H, 18-H), 1.99
(m, 1 H, 15-H), 1.98 (m, 1 H, 21-H), 1.91 (m, 1 H, 19-H),
1.81 (m, 1 H, 16-H), 1.78 (m, 1 H, Lys-β-CHH0), 1.72 (m, 1
H, 2-H), 1.63 (m, 1 H, 7-H), 1.61 (m, 1 H, 20-H), 1.60 (dd, 1
H, J = 13.6, 13.6 Hz, 190-H), 1.59 (m, 1 H, 6-H), 1.58 (m, 1
Methyl (3β)-3-[(L)-ornithyloxy)]-11-oxoolean-12-en-
30-oate (18)
Obtained from 32 by method B as a colorless pow- H, Lys-β-CHH0), 1.45 (m, 2 H, Lys-δ-CH2), 1.42 (m, 1 H,
der. Yield: 90 mg, 31%. M. p.: 219 – 223 ◦C. – Rf = 0.08 60-H), 1.41 (m, 2 H, Lys-γ-CH2), 1.39 (m, 1 H, 70-H), 1.36
(dichloromethane-methanol, 9 : 1). – [α]D = 103.91 (c = (m, 1 H, 22-H), 1.35 (s, 3 H, 27-H), 1.32 (m, 2 H, 220-H and
0.58, CHCl3). – UV/Vis (methanol): λmax(logε) = 249 nm 210-H), 1.17 (m, 1 H, 160-H), 1.15 (s, 3 H, 25-H), 1.13 (s, 3
(4.03). – IR (KBr): ν = 3438br, 2951s, 2872m, 1729s, 1655s, H, 29-H), 1.11 (s, 3 H, 26-H), 1.04 (m, 1 H, 1-H0), 1.00 (m, 1
1465m, 1388m, 1323w, 1217m, 1153m, 1086w, 1022w H, 15-H0), 0.88 (s, 3 H, 24-H), 0.86 (s, 3 H, 23-H), 0.80 (m, 1
cm−1. – 1H NMR (500 MHz, CDCl3): δ = 5.67 (s, 1 H, H, 5-H), 0.79 (s, 3 H, 28-H). – 13C NMR (125 MHz, CDCl3):
12-H), 4.56 (dd, 1 H, J = 11.4, 4.3 Hz, 3-H), 3.69 (s, 3 H, δ = 200.0 (C-11), 176.9 (C-30), 175.8 (Lys-COO), 169.2 (C-
OMe), 3.45 (m, 1 H, Orn-α-CH), 2.82 (ddd, 1 H, J = 13.5, 13), 128.5 (C-12), 80.7 (C-3), 61.7 (C-9), 55.0 (C-5), 54.7
3.5, 3.5 Hz, 1-H), 2.75 (m, 2 H, Orn-δ-CH2), 2.37 (s, 1 H, (Lys-α-CH), 51.7 (OMe), 48.4 (C-18), 45.4 (C-8), 44.0 (C-
9-H), 2.09 (m, 1 H, 18-H), 2.03 (m, 1 H, 15-H), 2.00 (m, 20), 43.2 (C-14), 41.9 (Lys-ε-CH2), 41.1 (C-19), 38.7 (C-
1 H, 21-H), 1.93 (m, 1 H, 19-H), 1.87 (m, 1 H, Orn-β- 1), 38.1 (C-4), 37.7 (C-22), 36.9 (C-10), 34.5 (Lys-β-CH2),
CHH0), 1.83 (m, 1 H, 16-H), 1.72 (m, 1 H, 2-H), 1.68 (m, 33.2 (Lys-δ-CH2), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21), 28.5
1 H, 7-H), 1.67 (m, 1 H, Orn-β-CHH0), 1.64 (m, 1 H, 20- (C-29), 28.3 (C-28), 28.1 (C-23), 26.4 (C-16), 26.4 (C-15),
H), 1.61 (dd, 1 H, J = 13.5, 13.5 Hz, 190-H), 1.60 (m, 1 23.6 (C-2), 23.3 (C-27), 22.9 (Lys-γ-CH2), 18.6 (C-26), 17.3
H, 6-H), 1.58 (m, 2 H, Orn-γ-CH2), 1.46 (m, 1 H, 60-H), (C-6), 16.8 (C-24), 16.3 (C-25). – MS (ESI): m/z (%) =
1.42 (m, 1 H, 70-H), 1.41 (m, 1 H, 22-H), 1.38 (s, 3 H, 27- 613.4 (100) [M+H]+, 671.3 (38) [M+2NH4+MeOH]+. –
H), 1.32 (m, 2 H, 220-H and 210-H), 1.19 (m, 1 H, 160-H), C37H60N2O5 (612.88): C 72.51, H 9.87, N 4.57; found C
1.15 (s, 3 H, 25-H), 1.13 (s, 3 H, 29-H), 1.11 (s, 3 H, 26- 72.37, H 9.99, N 4.51.
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740
R. Csuk et al. · Methyl Glycyrrhetinate Esterified with Amino Acids
Methyl (3β)-3-{N-[(tert-butoxycarbonyl)-sarcosyl]oxy}-
11-oxo-olean-12-en-30-oate (20)
H, Pro-γ-CH2), 1.79 (m, 1 H, 16-H), 1.63 (m, 1 H, 7-H), 1.62
(m, 1 H, 20-H), 1.60 (dd, 1 H, J = 13.6, 13.6 Hz, 190-H), 1.58
(m, 1 H, 6-H), 1.42 (m, 1 H, 60-H), 1.40 (m, 1 H, 70-H), 1.40
Obtained from 1 by method A as a colorless powder.
Yield: 420 mg, 94%. M. p.: 202 – 204 ◦C (decomp.). – Rf =
0.52 (hexane-ethyl acetate, 7 : 3). – [α]D = 102.81 (c = 0.48,
CHCl3). – UV/Vis (methanol): λmax(logε) = 250 nm (4.08).
– IR (KBr): ν = 3435br, 2972s, 1726s, 1701s, 1655s, 1618m,
1485m, 1457s, 1423m, 1392s, 1367s, 1320m, 1302m, 1264s,
1238s, 1219s, 1154s, 1088w, 1011w, 982m cm−1. – 1H NMR
(500 MHz, CDCl3): δ = 5.66 (s, 1 H, 12-H), 4.57 (dd, 1 H,
J = 11.3, 4.9 Hz, 3-H), 3.90 (s, 2 H, Sar-CH2), 3.68 (s, 3 H,
OMe), 2.93 (s, 3 H, NCH3), 2.81 (m, 1 H, 1-H), 2.36 (s, 1
H, 9-H), 2.08 (m, 1 H, 18-H), 2.02 (ddd, 1 H, J = 13.9, 13.9,
4.4 Hz, 15-H), 1.99 (m, 1 H, 21-H), 1.92 (ddd, 1 H, J = 13.4,
3.6, 2.4 Hz, 19-H), 1.82 (ddd, 1 H, J = 13.7, 13.7, 4.0 Hz,
16-H), 1.70 (m, 1 H, 2-H), 1.65 (m, 1 H, 20-H), 1.63 (m, 1 H,
7-H), 1.61 (dd, 1 H, J = 13.6, 13.6 Hz, 190-H), 1.57 (m, 1 H,
6-H), 1.43 (s, 9 H, Boc-CH3), 1.41 (m, 1 H, 60-H), 1.40 (m,
1 H, 70-H), 1.38 (m, 1 H, 22-H), 1.36 (s, 3 H, 27-H), 1.31 (m,
2 H, 220-H and 210-H), 1.18 (m, 1 H, 160-H), 1.16 (s, 3 H,
29-H), 1.14 (s, 3 H, 25-H), 1.12 (s, 3 H, 26-H), 1.06 (m, 1 H,
1-H0), 1.01 (m, 1 H, 15-H0), 0.89 (s, 3 H, 24-H), 0.88 (s, 3 H,
23-H), 0.81 (m, 1 H, 5-H), 0.80 (s, 3 H, 28-H). – 13C NMR
(125 MHz, CDCl3): δ = 200.0 (C-11), 176.9 (C-30), 169.7
(Sar-COO), 169.3 (C-13), 155.4 (Boc-COO), 128.5 (C-12),
81.6 (C-3), 80.1 (Boc-quart.-C), 61.7 (C-9), 55.0 (C-5), 51.7
(OMe), 51.3 (Sar-CH2), 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), 35.6 (NCH3), 32.7 (C-7), 31.8 (C-17), 31.1 (C-
21), 28.5 (C-28), 28.3 (Boc-CH3), 28.2 (C-29), 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). – MS (ESI): m/z
(%) = 656.0 (7) [M+H]+, 678.4 (100) [M+Na]+, 1006.3
(10) [3M+Na]2+. – C39H61NO7 (655.90): C 71.42, H 9.37,
N 2.14; found C 71.31, H 9.52, N 2.09.
(s, 9 H, Boc-CH3), 1.38 (m, 1 H, 22-H), 1.34 (s, 3 H, 27-H),
1.29 (m, 2 H, 220-H and 210-H), 1.17 (m, 1 H, 160-H), 1.14 (s,
3 H, 25-H), 1.12 (s, 3 H, 29-H), 1.09 (s, 3 H, 26-H), 1.04 (m,
1 H, 1-H0), 1.00 (m, 1 H, 15-H0), 0.86 (s, 3 H, 24-H), 0.85
(s, 3 H, 23-H), 0.80m, 1 H, 5-H), 0.78 (s, 3 H, 28-H). – 13
C
NMR (125 MHz, CDCl3): δ = 200.0 (C-11), 176.9 (C-30),
172.8 (Pro-COO), 169.3 (C-13), 155.9 (Boc-COO), 128.5
(C-12), 81.4 (C-3), 79.9 (Boc-quart.-C), 61.1 (C-9), 59.4
(Pro-α-CH), 55.0 (C-5), 51.7 (OMe), 48.4 (C-18), 46.3 (Pro-
δ-CH2), 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), 30.2 (Pro-β-CH2), 28.5 (C-29),
28.4 (Boc-CH3), 28.3 (C-28), 28.2 (C-23), 26.5 (C-16), 26.4
(C-15), 24.3 (Pro-γ-CH2), 23.5 (C-2), 23.3 (C-27), 18.7 (C-
26), 17.3 (C-6), 16.7 (C-24), 16.4 (C-25). – MS (ESI): m/z
(%) = 682.2 (10) [M+H]+, 704.4 (100) [M+Na]+, 1045.3
(8) [3M+2Na]2+, 1385.2 (14) [2M+Na]+. – C41H63NO7
(681.94): C 72.21, H 9.31, N 2.05; found C 72.00, H 9.55,
N 1.88.
Methyl (3β)-3-{N-[(tert-butoxycarbonyl)-(L)-
phenylalanyl]oxy}-11-oxo-olean-12-en-30-oate (22)
Obtained from 1 by method A as a colorless powder.
Yield: 630 mg, 80%. M. p.: 128 – 131 ◦C (decomp.). – Rf =
0.58 (hexane-ethyl acetate, 7 : 3). – [α]D = 92.60 (c = 0.51,
CHCl3). – UV/Vis (methanol): λmax(logε) = 249 nm (4.07).
– IR (KBr): ν = 3328br, 2973s, 2866s, 1731s, 1645s, 1531s,
1496s, 1455s, 1390s, 1366s, 1318s, 1280s, 1247s, 1167s,
1085m, 1050s, 1027m, 983s, 915w, 881w, 864m, 832w,
780w, 768w, 746m, 699s cm−1. – 1H NMR (500 MHz,
CDCl3): δ = 7.31–7.16 (br, 5 H, Phe-Ar), 5.67 (s, 1 H, 12-
H), 4.89 (d, 1 H, J = 8.8 Hz, Phe-NH), 4.57 (m, 1 H, Phe-α-
CH), 4.53 (dd, 1 H, J = 9.8, 5.3 Hz, 3-H), 3.69 (s, 3 H, OMe),
3.13 (dd, 1 H, J = 13.6, 5.9 Hz, Phe-β-CHH0), 3.04 (dd, 1 H,
J = 14.2, 6.4 Hz, Phe-β-CHH0), 2.80 (m, 1 H, 1-H), 2.35 (s,
Methyl (3β)-3-{N-[(tert-butoxycarbonyl)-(L)-prolyl]oxy}-
11-oxo-olean-12-en-30-oate (21)
Obtained from 1 by method A as a colorless powder. 1 H, 9-H), 2.08 (m, 1 H, 18-H), 2.03 (m, 1 H, 15-H), 1.99
Yield: 260 mg, 62%. M. p.: 155 – 158 ◦C (decomp.). – Rf = (m, 1 H, 21-H), 1.93 (ddd, 1 H, J = 13.3, 3.5, 1.9 Hz, 19-H),
0.42 (hexane-ethyl acetate, 7 : 3). – [α]D = 68.01 (c = 1.82 (ddd, 1 H, J = 13.6, 13.6, 4.5 Hz, 16-H), 1.68 (m, 1 H,
0.26, CHCl3). – UV/Vis (methanol): λmax(logε) = 249 nm 2-H), 1.66 (m, 1 H, 7-H), 1.63 (m, 1 H, 20-H), 1.61 (dd, 1 H,
(4.04). – IR (KBr): ν = 3442br, 2972s, 2876m, 2361w, J = 13.6, 13.6 Hz, 190-H), 1.55 (m, 1 H, 6-H), 1.45 (m, 1 H,
1731s, 1694s, 1657s, 1619w, 1455m, 1401s, 1365m, 1324m, 60-H), 1.42 (m, 1 H, 70-H), 1.41 (m, 1 H, 22-H), 1.40 (s, 9 H,
1281m, 1262m, 1215s, 1160s, 1126m, 1084m, 1021w, 988m Boc-CH3), 1.36 (s, 3 H, 27-H), 1.31 (m, 2 H, 220-H and 210-
cm−1. – 1H NMR (500 MHz, CDCl3): δ = 5.64 (s, 1 H, 12- H), 1.18 (m, 1 H, 160-H), 1.15 (s, 3 H, 25-H), 1.15 (s, 3 H,
H), 4.51 (m, 1 H, 3-H), 4.21 (m, 1 H, Pro-α-CH), 3.67 (s, 3 29-H), 1.12 (s, 3 H, 26-H), 1.07 (m, 1 H, 1-H0), 1.02 (m, 1 H,
H, OMe), 3.50 (m, 1 H, Pro-δ-CHH0), 3.40 (m, 1 H, Pro-δ- 15-H0), 0.82 (s, 3 H, 24-H), 0.81 (s, 3 H, 23-H), 0.81 (s, 3 H,
CHH0), 2.79 (ddd, 1 H, J = 13.7, 3.3, 3.3 Hz, 1-H), 2.33 (s, 28-H), 0.78 (m, 1 H, 5-H). – 13C NMR (125 MHz, CDCl3):
1 H, 9-H), 2.20 (m, 1 H, Pro-β-CHH0), 2.06 (m, 1 H, 18-H), δ = 200.0 (C-11), 176.9 (C-30), 171.8 (Phe-COO), 169.2
1.98 (m, 1 H, 15-H), 1.96 (m, 1 H, 21-H), 1.94 (m, 1 H, Pro- (C-13), 157.3 (Boc-COO), 136.1 (Phe-γ-C), 129.4 (Phe-Ar),
β-CHH0), 1.90 (m, 1 H, 19-H), 1.86 (m, 1 H, 2-H), 1.85 (m, 2 128.5 (C-12), 128.5 (Phe-Ar), 82.1 (C-3), 79.8 (Boc-quart.-
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741
C), 61.7 (C-9), 55.0 (C-5), 54.7 (Phe-α-CH), 51.7 (OMe), Methyl (3β)-3-{N-[(tert-butoxycarbonyl)-(L)-valyl]oxy}-11-
48.4 (C-18), 45.4 (C-8), 44.0 (C-20), 43.2 (C-14), 41.1 (C- oxo-olean-12-en-30-oate (24)
19), 38.7 (C-1), 38.4 (Phe-β-CH2), 38.0 (C-4), 37.7 (C-22),
Obtained from 1 by method A as a colorless powder.
36.9 (C-10), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21), 28.5 (C-
Yield: 420 mg, 96%. M. p.: 209 – 213 ◦C (decomp.). – Rf =
28), 28.3 (Boc-CH3), 28.3 (C-29), 28.0 (C-23), 26.5 (C-16),
26.4 (C-15), 23.4 (C-2), 23.3 (C-27), 18.7 (C-26), 17.3 (C-6),
0.66 (hexane-ethyl acetate, 7 : 3). – [α]D = 78.84 (c = 0.33,
CHCl3). – UV/Vis (methanol): λmax(logε) = 249 nm (3.95).
16.7 (C-24), 16.3 (C-25). – MS (ESI): m/z (%) = 732.1 (18)
– IR (KBr): ν = 3401br, 2968s, 2874m, 2120w, 1727s,
[M+H]+, 749.3 (10) [M+NH4]+, 754.4 (100) [M+Na]+,
1659s, 1511m, 1465m, 1391m, 1367m, 1305m, 1258m,
1119.8 (8) [3M+2Na]2+, 1464.0 (6) [2M+2H]+, 1486.2
1
1216m, 1161s, 1087m, 1020w m−1. – H NMR (500 MHz,
(14) [2M+Na]+. – C45H65NO7 (732.00): C 73.84, H 8.95,
CDCl3): δ = 5.66 (s, 1 H, 12-H), 4.99 (d, 1 H, J = 8.8 Hz,
Val-NH), 4.55 (dd, 1 H, J = 11.4, 4.9 Hz, 3-H), 4.22 (dd, 1 H,
N 1.91; found C 73.68, H 9.02, N 1.76.
J = 8.8, 4.0 Hz, Val-α-CH), 3.68 (s, 3 H, OMe), 2.81 (ddd,
Methyl (3β)-3-{N-[(tert-butoxycarbonyl)-(L)-
methionyl]oxy}-11-oxo-olean-12-en-30-oate (23)
1 H, J = 13.7, 3.4, 3.4 Hz, 1-H), 2.35 (s, 1 H, 9-H), 2.17
(m, 1 H, Val-β-CH), 2.08 (dd, 1 H, J = 14.1, 3.4 Hz, 18-H),
2.02 (m, 1 H, 15-H), 1.99 (m, 1 H, 21-H), 1.92 (ddd, 1 H,
J = 13.9, 4.0, 2.3 Hz, 19-H), 1.82 (m, 1 H, 16-H), 1.72 (m, 1
H, 2-H), 1.66 (m, 1 H, 7-H), 1.63 (m, 1 H, 20-H), 1.61 (dd, 1
H, J = 13.5, 13.5 Hz, 190-H), 1.58 (m, 1 H, 6-H), 1.46 (m, 1
H, 60-H), 1.44 (s, 9 H, Boc-CH3), 1.43 (m, 1 H, 70-H), 1.38
(m, 1 H, 22-H), 1.36 (s, 3 H, 27-H), 1.31 (m, 2 H, 220-H and
210-H), 1.18 (m, 1 H, 160-H), 1.16 (s, 3 H, 25-H), 1.14 (s, 3
H, 29-H), 1.12 (s, 3 H, 26-H), 1.08 (m, 1 H, 1-H0), 1.03 (m,
1 H, 15-H0), 0.99 (d, 3 H, Val-CH3, J = 6.8 Hz), 0.88 (m, 3
H, Val-CH3), 0.89 (s, 3 H, 24-H), 0.88 (s, 3 H, 23-H), 0.80
(s, 3 H, 28-H), 0.79 (m, 1 H, 5-H). – 13C NMR (125 MHz,
CDCl3): δ = 199.9 (C-11), 176.9 (C-30), 172.0 (Val-COO),
169.2 (C-13), 155.7 (Boc-COO), 128.5 (C-12), 81.9 (C-3),
79.6 (Boc-quart.-C), 61.7 (C-9), 58.9 (Val-α-CH), 55.0 (C-
5), 51.7 (OMe), 48.4 (C-18), 45.3 (C-8), 44.0 (C-20), 43.2
(C-14), 41.1 (C-19), 38.7 (C-1), 38.0 (C-4), 37.7 (C-22),
36.9 (C-10), 32.7 (C-7), 31.8 (C-17), 31.2 (Val-β-CH), 31.1
(C-21), 28.5 (C-28), 28.3 (Boc-CH3), 28.3 (C-29), 28.1 (C-
23), 26.5 (C-16), 26.4 (C-15), 23.6 (C-2), 23.3 (C-27), 19.3
(Val-CH3), 18.7 (C-26), 17.3 (C-6), 17.2 (Val-CH3), 16.8
(C-24), 16.3 (C-25). – MS (ESI): m/z (%) = 684.1 (10)
[M+H]+, 701.3 (15) [M+NH4]+, 706.3 (100) [M+Na]+,
1048.3 (10) [3M+2Na+H]2+, 1367.0 (8) [2M+H]+, 1390.1
(20) [2M+Na]+. – C41H65NO7 (683.96): C 72.00, H 9.58,
N 2.05; found C 71.92, H 9.77, N 1.90.
Obtained from 1 by method A as a colorless powder.
Yield: 410 mg, 96%. M. p.: 220 – 223 ◦C (decomp.). – Rf =
0.56 (hexane-ethyl acetate, 7 : 3). – [α]D = 69.15 (c =
0.25, CHCl3). – UV/Vis (methanol): λmax(logε) = 249 nm
(4.01). – IR (KBr): ν = 3386br, 2972s, 2873m, 1724s, 1655s,
1513m, 1455m, 1390m, 1367m, 1249m, 1217s, 1166s,
1086m, 1049w, 1024w, 984m, 916m cm−1. – 1H NMR
(500 MHz, CDCl3): δ = 5.66 (s, 1 H, 12-H), 5.10 (d, 1 H,
J = 7.5, Met-NH), 4.56 (dd, 1 H, J = 11.7, 4.7 Hz, 3-H),
4.39 (m, 1 H, Met-α-CH), 3.68 (s, 3 H, OMe), 2.82 (ddd, 1
H, J = 13.7, 3.6, 3.6 Hz, 1-H), 2.55 (m, 2 H, Met-β-CH2),
2.35 (s, 1 H, 9-H), 2.15 (m, 1 H, Met-γ-CHH0), 2.10 (s, 3 H,
Met-CH3), 2.08 (m, 1 H, 18-H), 2.02 (m, 1 H, 15-H), 1.99
(m, 1 H, 21-H), 1.93 (m, 1 H, 19-H), 1.84 (m, 1 H, 16-H),
1.75 (m, 1 H, Met-γ-CHH0), 1.72 (m, 1 H, 2-H), 1.66 (m, 1
H, 7-H), 1.63 (m, 1 H, 20-H), 1.61 (dd, 1 H, J = 13.6, 13.6 Hz,
190-H), 1.57 (m, 1 H, 6-H), 1.48 (m, 1 H, 60-H), 1.44 (s, 9 H,
Boc-CH3), 1.42 (m, 1 H, 70-H), 1.38 (m, 1 H, 22-H), 1.36
(s, 3 H, 27-H), 1.31 (m, 2 H, 220-H and 210-H), 1.18 (m, 1
H, 160-H), 1.16 (s, 3 H, 25-H), 1.15 (s, 3 H, 29-H), 1.13 (s,
3 H, 26-H), 1.05 (ddd, 1 H, J = 13.6, 13.6, 3.6 Hz, 1-H0),
1.01 (m, 1 H, 15-H0), 0.90 (s, 3 H, 24-H), 0.88 (s, 3 H, 23-
H), 0.80 (s, 3 H, 28-H), 0.80 (m, 1 H, 5-H). – 13C NMR
(125 MHz, CDCl3): δ = 199.9 (C-11), 176.9 (C-30), 171.9
(Met-COO), 169.2 (C-13), 155.3 (Boc-COO), 128.5 (C-12),
82.2 (C-3), 79.9 (Boc-quart.-C), 61.6 (C-9), 55.0 (C-5), 53.2
(Met-α-CH), 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), 38.1 (C-4), 37.7
Methyl (3β)-3-{N-[(tert-butoxycarbonyl)-(L)-
isoleucyl]oxy}-11-oxo-olean-12-en-30-oate (25)
Obtained from 1 by method A as a colorless powder.
(C-22), 36.9 (C-10), 32.6 (C-7), 32.5 (Met-γ-CH2), 31.8 (C- Yield: 220 mg, 49%. M. p.: 183 – 186 ◦C (decomp.). – Rf =
17), 31.1 (C-21), 30.0 (Met-β-CH2), 28.5 (C-28), 28.3 (Boc- 0.69 (hexane-ethyl acetate, 7 : 3). – [α]D = 87.63 (c =
CH3), 28.3 (C-29), 28.2 (C-23), 26.4 (C-16), 26.4 (C-15), 0.54, CHCl3). – UV/Vis (methanol): λmax(logε) = 249 nm
23.5 (C-2), 23.3 (C-27), 18.7 (C-26), 17.3 (C-6), 16.8 (C- (3.91). – IR (KBr): ν = 3387br, 2968s, 2876m, 1728s, 1652s,
24), 16.3 (C-25), 15.4 (Met-CH3). – MS (ESI): m/z (%) = 1510m, 1464m, 1390m, 1365m, 1335m, 1290m, 1248m,
733.1 (10) [M+NH4]+, 738.3 (100) [M+Na]+, 1096.1 (6) 1215s, 1159s, 1085m, 1049m, 1023m, 984m cm−1. – 1H
[3M+2Na+H]2+, 1453.6 (7) [2M+Na]+. – C41H65NO7S NMR (500 MHz, CDCl3): δ = 5.66 (s, 1 H, 12-H), 4.99 (d,
(716.02): C 68.77, H 9.15, N 1.96. – S, 4.48; found C 68.72, 1 H, J = 9.0 Hz, Ile-NH), 4.56 (dd, 1 H, J = 11.4, 4.9 Hz,
H 9.32, N 1.85. – S, 4.32.
3-H), 4.26 (dd, 1 H, J = 9.0, 3.8 Hz, Ile-α-CH), 3.69 (s, 3
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R. Csuk et al. · Methyl Glycyrrhetinate Esterified with Amino Acids
H, OMe), 2.81 (ddd, 1 H, J = 13.7, 3.5, 3.5 Hz, 1-H), 2.35 (s, 3 H, 25-H), 1.15 (s, 3 H, 29-H), 1.12 (s, 3 H, 26-H),
(s, 1 H, 9-H), 2.08 (dd, 1 H, J = 14.0, 3.4 Hz, 18-H), 2.02 1.04 (m, 1 H, 1-H0), 1.01 (m, 1 H, 15-H0), 0.96 (d, 3 H,
(m, 1 H, 15-H), 1.99 (m, 1 H, 21-H), 1.90 (m, 1 H, 19-H), J = 6.4 Hz, Leu-γ-CH3), 0.95 (d, 3 H, J = 6.4 Hz, Leu-γ-
1.82 (m, 1 H, Ile-β-CH), 1.82 (m, 1 H, 16-H), 1.70 (m, 1 H, CH3), 0.89 (s, 3 H, 24-H), 0.87 (s, 3 H, 23-H), 0.80 (s, 3 H,
2-H), 1.66 (m, 1 H, 7-H), 1.63 (m, 1 H, 20-H), 1.61 (dd, 1 H, 29-H), 0.80 (m, 1 H, 5-H). – 13C NMR (125 MHz, CDCl3):
J = 13.6, 13.6 Hz, 190-H), 1.56 (m, 1 H, 6-H), 1.45 (m, 1 H, δ = 199.9 (C-11), 176.9 (C-30), 173.1 (Leu-COO), 169.2
60-H), 1.44 (s, 9 H, Boc-CH3), 1.41 (m, 1 H, 70-H), 1.40 (m, (C-13), 155.3 (Boc-COO), 128.5 (C-12), 81.6 (C-3), 79.6
2 H, Ile-γ-CH2), 1.38 (m, 1 H, 22-H), 1.36 (s, 3 H, 27-H), (Boc-quart.-C), 61.7 (C-9), 55.0 (C-5), 52.5 (Leu-α-CH),
1.31 (m, 2 H, 220-H and 210-H), 1.18 (m, 1 H, 160-H), 1.16 51.7 (OMe), 48.4 (C-18), 45.4 (C-8), 44.0 (C-20), 43.2 (C-
(s, 3 H, 25-H), 1.15 (s, 3 H, 29-H), 1.13 (s, 3 H, 26-H), 1.08 14), 42.0 (Leu-β-CH2), 41.1 (C-19), 38.7 (C-1), 38.1 (C-4),
(m, 1 H, 1-H0), 1.01 (m, 1 H, 15-H0), 0.96 (d, 3 H, J = 6.8 Hz, 37.7 (C-22), 36.9 (C-10), 32.7 (C-7), 31.8 (C-17), 31.1 (C-
Ile-β-CH3), 0.91 (t, 3 H, J = 7.3 Hz, Ile-γ-CH3), 0.90 (s, 3 21), 28.5 (C-28), 28.3 (Boc-CH3), 28.3 (C-29), 28.2 (C-23),
H, 24-H), 0.88 (s, 3 H, 23-H), 0.80 (s, 3 H, 28-H), 0.79 (m, 1 26.4 (C-16), 26.4 (C-15), 24.8 (Leu-γ-CH), 23.5 (C-2), 23.3
H, 5-H). – 13C NMR (125 MHz, CDCl3): δ = 199.9 (C-11), (C-27), 22.9 (Leu-γ-CH3), 21.9 (Leu-γ-CH3), 18.7 (C-26),
176.9 (C-30), 171.9 (Ile-COO), 169.2 (C-13), 155.6 (Boc- 17.3 (C-6), 16.7 (C-24), 16.3 (C-25). – MS (ESI): m/z (%)
COO), 128.5 (C-12), 81.9 (C-3), 79.6 (Boc-quart.-C), 61.7 = 697.9 (10) [2M+H]2+, 720.3 (100) [M+Na]+, 1069.3
(C-9), 58.5 (Ile-α-CH), 55.0 (C-5), 51.7 (OMe), 48.4 (C- (4) [3M+2Na]2+, 1418.1 (12) [2M+Na]+. – C42H67NO7
18), 45.4 (C-8), 44.0 (C-20), 43.2 (C-14), 41.1 (C-19), 38.7 (697.98): C 72.27, H 9.68, N 2.01; found C 72.17, H 9.83,
(C-1), 38.0 (C-4), 37.9 (Ile-β-CH), 37.7 (C-22), 36.9 (C- N 1.88.
10), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21), 28.5 (C-28), 28.3
(Boc-CH3), 28.3 (C-29), 28.1 (C-23), 26.4 (C-16), 26.4 (C-
Methyl (3β)-3-({4-[(tert-butoxycarbonyl)amino]butanoyl}-
oxy)-11-oxoolean-12-en-30-oate (27)
15), 24.7 (Ile-γ-CH2), 23.6 (C-2), 23.3 (C-27), 18.7 (C-26),
17.3 (C-6), 16.8 (C-24), 16.3 (C-25), 15.7 (Ile-β-CH3), 11.6
Obtained from 1 by method A as a colorless powder.
(Ile-γ-CH3). – MS (ESI): m/z (%) = 698.2 (16) [M+H]+,
Yield: 440 mg, 52%. M. p.: 195 – 198 ◦C (decomp.). – Rf =
709.7 (8) [2M+Na+H]2+, 715.2 (15) [M+NH4]+, 720.4
0.38 (hexane-ethyl acetate, 7 : 3). – [α]D = 108.46 (c = 0.43,
(100) [M+Na]+, 1058.2 (4) [3M+Na+2H]2+, 1066.7 (7)
CHCl3). – UV/Vis (methanol): λmax(logε) = 249 nm (4.08).
[3M+K+2H]2+, 1069.3 (12) [3M+2Na]2+, 1418.1 (22)
– IR (KBr): ν = 3329br, 2965s, 2873m, 1733s, 1706s, 1682s,
[2M+Na]+. – C42H67NO7 (697.98): C 72.27, H 9.68, N
1653s, 1616w, 1537m, 1454m, 1390m, 1365m, 1324m,
2.01; found C 72.07, H 9,81, N 1.89.
1252m, 1210m, 1171s, 1087w, 1044w, 1026w cm−1. – 1H
NMR (500 MHz, CDCl3): δ = 5.66 (s, 1 H, 12-H), 4.62 (br,
Methyl (3β)-3-{N-[(tert-butoxycarbonyl)-(L)-leucyl]oxy}-
1 H, chain-NH), 4.56 (dd, 1 H, J = 11.5, 4.7 Hz, 3-H), 3.69
11-oxo-olean-12-en-30-oate (26)
(s, 3 H, OMe), 3.17 (dt, 2 H, J = 6.4, 6.4 Hz, chain-γ-CH2),
Obtained from 1 by method A as a colorless powder. 2.81 (ddd, 1 H, J = 13.7, 3.4, 3.4 Hz, 1-H), 2.36 (s, 1 H,
Yield: 460 mg, 98%. M. p.: 215 – 219 ◦C (decomp.). – Rf = 9-H), 2.35 (t, 2 H, J = 7.4 Hz, chain-α-CH2), 2.08 (dd, 1
0.65 (hexane-ethyl acetate, 7 : 3). – [α]D = 73.31 (c = H, J = 14.1, 3.8 Hz, 18-H), 2.03 (m, 1 H, 15-H), 1.99 (m,
0.30, CHCl3). – UV/Vis (methanol): λmax(logε) = 249 nm 1 H, 21-H), 1.93 (ddd, 1 H, J = 13.5, 3.8, 2.5 Hz, 19-H,),
(4.04). – IR (KBr): ν = 3387br, 2955s, 2871m, 1731s, 1661s, 1.82 (m, 1 H, 16-H), 1.81 (m, 2 H, chain-β-CH2), 1.70 (m,
1506m, 1455m, 1390m, 1367m, 1250m, 1216s, 1166s, 1 H, 2-H), 1.66 (m, 1 H, 7-H), 1.63 (m, 1 H, 20-H), 1.61
1087w, 1048w, 1021w, 985m cm−1. – H NMR (500 MHz, (dd, 1 H, J = 13.5, 13.5 Hz, 190-H), 1.58 (m, 1 H, 6-H), 1.45
1
CDCl3): δ = 5.66 (s, 1 H, 12-H), 4.87 (m, 1 H, Leu-NH), (m, 1 H, 60-H), 1.44 (s, 9 H, Boc-CH3), 1.41 (m, 1 H, 70-
4.54 (dd, 1 H, J = 11.7, 4.7 Hz, 3-H), 4.29 (m, 1 H, Leu- H), 1.38 (m, 1 H, 22-H), 1.36 (s, 3 H, 27-H), 1.31 (m, 2 H,
α-CH), 3.68 (s, 3 H, OMe), 2.81 (ddd, 1 H, J = 13.6, 3.5, 220-H and 210-H), 1.18 (m, 1 H, 160-H), 1.16 (s, 3 H, 25-
3.5 Hz, 1-H), 2.35 (s, 1 H, 9-H), 2.08 (dd, 1 H, J = 13.9, H), 1.15 (s, 3 H, 29-H), 1.13 (s, 3 H, 26-H), 1.05 (ddd, 1 H,
3.6 Hz, 18-H), 2.02 (m, 1 H, 15-H), 1.99 (m, 1 H, 21-H), J = 13.6, 13.6, 4.0 Hz, 1-H0), 1.02 (m, 1 H, 15-H0), 0.88 (s,
1.92 (ddd, 1 H, J = 13.5, 3.4, 2.7 Hz, 19-H), 1.82 (ddd, 1 3 H, 24-H), 0.87 (s, 3 H, 23-H), 0.81 (s, 3 H, 28-H), 0.80 (m,
H, J = 13.5, 13.5, 4.1 Hz, 16-H), 1.76 (m, 1 H, Leu-γ-CH), 1 H, 5-H). – 13C NMR (125 MHz, CDCl3): δ = 199.7 (C-
1.72 (m, 1 H, 2-H), 1.66 (m, 1 H, 7-H), 1.63 (m, 1 H, 20- 11), 176.7 (C-30), 172.8 (chain-COO), 168.9 (C-13), 155.8
H), 1.61 (dd, 1 H, J = 13.5, 13.5 Hz, 190-H), 1.59 (m, 1 H, (Boc-COO), 128.4 (C-12), 80.7 (C-3), 79.6 (Boc-quart.-C),
Leu-β-CHH0), 1.58 (m, 1 H, 6-H), 1.48 (m, 1 H, Leu-β- 61.8 (C-9), 55.1 (C-5), 51.8 (OMe), 48.5 (C-18), 45.5 (C-8),
CHH0), 1.44 (s, 9 H, Boc-CH3), 1.44 (m, 1 H, 60-H), 1.42 44.1 (C-20), 43.3 (C-14), 41.2 (C-19), 40.2 (chain-γ-CH2),
(m, 1 H, 70-H), 1.39 (m, 1 H, 22-H), 1.36 (s, 3 H, 27-H), 38.9 (C-1), 38.2 (C-4), 37.8 (C-22), 37.1 (C-10), 32.8 (C-7),
1.31 (m, 2 H, 220-H and 210-H), 1.18 (m, 1 H, 160-H), 1.16 32.1 (chain-α-CH2), 31.9 (C-17), 31.3 (C-21), 28.6 (C-28),
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743
28.5 (Boc-CH3), 28.4 (C-29), 28.2 (C-23), 26.6 (C-16), 26.6 Methyl (3β)-3-({6-[(tert-butoxycarbonyl)amino]hexanoyl}-
(C-15), 25.5 (chain-β-CH2), 23.7 (C-2), 23.4 (C-27), 18.8 oxy)-11-oxoolean-12-en-30-oate (29)
(C-26), 17.5 (C-6), 16.9 (C-24), 16.5 (C-25). – MS (ESI):
Obtained from 1 by method A as a colorless powder.
m/z (%) = 670.4 (4) [M+H]+, 689.6 (1) [2M+K+H]2+
,
Yield: 290 mg, 64%. M. p.: 140 – 143 ◦C. – Rf = 0.44
(hexane-ethyl acetate, 7 : 3). – [α]D = 77.46 (c = 0.51,
CHCl3). – UV/Vis (methanol): λmax(logε) = 249 nm (4.02).
– IR (KBr): ν = 3406br, 2934s, 1732s, 1652s, 1515m,
1456m, 1390m, 1366m, 1251m, 1212m, 1169s, 1087w
cm−1. – 1H NMR (500 MHz, CDCl3): δ = 5.66 (s, 1 H, 12-
H), 4.52 (dd, 1 H, J = 11.5, 4.7 Hz, 3-H), 4.51 (br, 1 H, chain-
NH), 3.69 (s, 3 H, OMe), 3.11 (dt, 2 H, J = 5.8, 5.8 Hz, chain-
ε-CH2), 2.80 (ddd, 1 H, J = 13.7, 3.4, 3.4 Hz, 1-H), 2.36 (s,
1 H, 9-H), 2.31 (dt, 2 H, J = 7.4, 2.1 Hz, chain-α-CH2), 2.08
(dd, 1 H, J = 13.8, 3.9 Hz, 18-H), 2.03 (m, 1 H, 15-H), 1.99
(m, 1 H, 21-H), 1.92 (ddd, 1 H, J = 13.5, 3.5, 2.7 Hz, 19-H),
1.82 (ddd, 1 H, J = 13.6, 13.6, 4.6 Hz, 16-H), 1.70 (m, 1 H,
2-H), 1.67 (m, 1 H, 7-H), 1.64 (m, 2 H, chain-β-CH2), 1.62
(m, 1 H, 20-H), 1.61 (dd, 1 H, J = 13.7, 13.7 Hz, 190-H,),
1.57 (m, 1 H, 6-H), 1.49 (m, 2 H, chain-δ-CH2), 1.46 (m, 1
H, 60-H), 1.43 (s, 9 H, Boc-CH3), 1.41 (m, 1 H, 70-H), 1.37
(m, 1 H, 22-H), 1.36 (s, 3 H, 27-H), 1.35 (m, 2 H, chain-β-
CH2), 1.31 (m, 2 H, 220-H and 210-H), 1.18 (m, 1 H, 160-H),
1.16 (s, 3 H, 25-H), 1.15 (s, 3 H, 29-H), 1.13 (s, 3 H, 26-H),
1.05 (ddd, 1 H, J = 13.6, 13.6, 3.8 Hz, 1-H0), 1.01 (m, 1 H,
15-H0), 0.88 (s, 3 H, 24-H), 0.87 (s, 3 H, 23-H), 0.80 (s, 3 H,
28-H), 0.80 (m, 1 H, 5-H). – 13C NMR (125 MHz, CDCl3):
δ = 200.0 (C-11), 176.9 (C-30), 173.3 (chain-COO), 169.2
(C-13), 155.9 (Boc-COO), 128.5 (C-12), 80.4 (C-3), 78.4
(Boc-quart.-C), 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), 40.4
(chain-ε-CH2), 38.7 (C-1), 38.1 (C-4), 37.7 (C-22), 36.9 (C-
10), 34.6 (chain-α-CH2), 32.7 (C-7), 31.8 (C-17), 31.1 (C-
21), 29.7 (chain-δ-CH2), 28.5 (C-28), 28.4 (Boc-CH3), 28.3
(C-29), 28.1 (C-23), 26.4 (C-16), 26.4 (C-15), 26.3 (chain-β-
CH2), 24.7 (chain-γ-CH2), 23.6 (C-2), 23.3 (C-27), 18.6 (C-
26), 17.4 (C-6), 16.7 (C-24), 16.4 (C-25). – MS (ESI): m/z
(%) = 698.3 (66) [M+H]+, 720.5 (100) [M+Na]+, 1417.4
(24) [2M+Na]+. – C42H67NO7 (697.98): C 72.27, H 9.68,
N 2.01; found C 72.18, H 9.83, N 1.91.
692.5 (100) [M+Na]+, 1024.8 (6) [3M+K+2H]2+, 1027.4
(30) [3M+2Na]2+, 1361.3 (26) [2M+Na]+. – C40H63NO7
(669.93): C 71.71, H 9.48, N 2.09; found C 71.58, H 9.54, N
2.00.
Methyl (3β)-3-({5-[(tert-butoxycarbonyl)amino]-
pentanoyl}oxy)-11-oxoolean-12-en-30-oate (28)
Obtained from 1 by method A as a colorless powder.
Yield: 470 mg, 47%. M. p.: 185 – 188 ◦C. – Rf = 0.35
(hexane-ethyl acetate, 7 : 3). – [α]D = 110.18 (c = 0.47,
CHCl3). – UV/Vis (methanol): λmax(logε) = 248 nm (4.18).
– IR (KBr): ν = 3401br, 2970s, 2872m, 1732s, 1714s, 1660s,
1619w, 1520m, 1458m, 1386m, 1364m, 1345w, 1318w,
1279m, 1249s, 1212m, 1170s, 1141m, 1105m, 1088w,
1020w, 982m cm−1. – 1H NMR (500 MHz, CDCl3): δ =
5.67 (s, 1 H, 12-H), 4.54 (br, 1 H, chain-NH), 4.52 (dd, 1
H, J = 11.6, 4.8 Hz, 3-H), 3.69 (s, 3 H, OMe), 3.13 (dt, 2
H, J = 6.2, 6.2 Hz, chain-δ-CH2), 2.80 (ddd, 1 H, J = 13.6,
3.4, 3.4 Hz, 1-H), 2.36 (s, 1 H, 9-H), 2.33 (t, 2 H, J = 7.4 Hz,
chain-α-CH2), 2.08 (dd, 1 H, J = 14.0, 4.2 Hz, 18-H), 2.03
(m, 1 H, 15-H), 1.99 (m, 1 H, 21-H), 1.93 (ddd, 1 H, J = 13.7,
3.5, 2.7 Hz, 19-H), 1.83 (ddd, 1 H, J = 13.6, 13.6, 4.7 Hz,
16-H), 1.70 (m, 1 H, 2-H), 1.66 (m, 2 H, chain-β-CH2),
1.66 (m, 1 H, 7-H), 1.63 (m, 1 H, 20-H), 1.61 (dd, 1 H,
J = 13.3, 13.3 Hz, 190-H), 1.57 (m, 1 H, 6-H), 1.52 (m, 2
H, chain-γ-CH2), 1.46 (m, 1 H, 60-H), 1.44 (s, 9 H, Boc-
CH3), 1.42 (m, 1 H, 70-H), 1.39 (m, 1 H, 22-H), 1.37 (s, 3
H, 27-H), 1.32 (m, 2 H, 220-H and 210-H), 1.18 (m, 1 H,
160-H), 1.17 (s, 3 H, 25-H), 1.15 (s, 3 H, 29-H), 1.13 (s,
3 H, 26-H), 1.06 (ddd, 1 H, J = 13.4, 13.4, 3.9 Hz, 1-H0),
1.01 (m, 1 H, 15-H0), 0.88 (s, 3 H, 24-H), 0.87 (s, 3 H, 23-
H), 0.81 (s, 3 H, 28-H), 0.80 (m, 1 H, 5-H). – 13C NMR
(125 MHz, CDCl3): δ = 199.9 (C-11), 176.8 (C-30), 172.2
(chain-COO), 169.1 (C-13), 155.8 (Boc-COO), 128.5 (C-
12), 80.5 (C-3), 78.3 (Boc-quart.-C), 61.7 (C-9), 54.9 (C-5),
51.7 (OMe), 48.3 (C-18), 45.3 (C-8), 43.9 (C-20), 43.1 (C-
14), 41.0 (C-19), 40.0 (chain-δ-CH2), 38.7 (C-1), 38.0 (C-4),
37.6 (C-22), 36.9 (C-10), 34.2 (chain-α-CH2), 32.6 (C-7),
Methyl (3β)-3-({6-[(tert-butoxycarbonyl)amino]octanoyl}-
oxy)-11-oxoolean-12-en-30-oate (30)
Obtained from 1 by method A as a colorless powder.
31.7 (C-17), 31.0 (C-21), 29.5 (chain-γ-CH2), 28.4 (C-28), Yield: 490 mg, 70%. M. p.: 150 – 152 ◦C. – Rf = 0.52
28.3 (Boc-CH3), 28.2 (C-29), 28.0 (C-23), 26.4 (C-16), 26.3 (hexane-ethyl acetate, 7 : 3). – [α]D = 98.61 (c = 0.58,
(C-15), 23.5 (C-2), 23.2 (C-27), 22.1 (chain-β-CH2), 18.6 CHCl3). – UV/Vis (methanol): λmax(logε) = 249 nm (4.08).
(C-26), 17.3 (C-6), 16.7 (C-24), 16.3 (C-25). – MS (ESI): – IR (KBr): ν = 3384br, 2929s, 2859s, 1715s, 1656s, 1620m,
m/z (%) = 684.3 (15) [M+H]+, 695.7 (2) [2M+Na+H]2+
,
1531s, 1456s, 1392s, 1365s, 1348m, 1322m, 1252s, 1211s,
706.5 (100) [M+Na]+, 1045.3 (4) [3M+K+2H]2+, 1048.3 1171s, 1090m, 1014m, 986m cm−1. – H NMR (500 MHz,
(19) [3M+2Na]2+, 1389.2 (26) [3M+2Na]2+, 1405.1 (3) CDCl3): δ = 5.66 (s, 1 H, 12-H), 4.52 (dd, 1 H, J = 11.6,
[2M+K]+. – C41H65NO7 (683.96): C 72.00, H 9.58, N 2.05; 4.8 Hz, 3-H), 4.51 (br, 1 H, chain-NH), 3.69 (s, 3 H, OMe),
1
found C 71.87, H 9.75, N 1.93.
3.09 (m, 2 H, chain-η-CH2), 2.80 (ddd, 1 H, J = 13.7, 3.5,
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R. Csuk et al. · Methyl Glycyrrhetinate Esterified with Amino Acids
3.5 Hz, 1-H), 2.36 (s, 1 H, 9-H), 2.29 (t, 2 H, J = 7.4 Hz, H, 1-H0), 1.04 (m, 1 H, 15-H0), 0.88 (s, 3 H, 24-H), 0.87 (s,
chain-α-CH2), 2.08 (dd, 1 H, J = 13.8, 4.1 Hz, 18-H), 2.03 3 H, 23-H), 0.81 (s, 3 H, 28-H), 0.79 (m, 1 H, 5-H). – 13C
(m, 1 H, 15-H), 1.99 (m, 1 H, 21-H), 1.93 (ddd, 1 H, J = 13.4, NMR (125 MHz, CDCl3): δ = 199.9 (C-11), 176.9 (C-30),
4.3, 2.9 Hz, 19-H), 1.83 (ddd, 1 H, J = 13.5, 13.5, 4.4 Hz, 172.4 (Dab-COO), 169.2 (C-13), 155.9 (Boc-COO), 128.4
16-H), 1.70 (m, 1 H, 2-H), 1.65 (m, 1 H, 7-H), 1.63 (m, 2 H, (C-12), 82.3 (C-3), 80.0 (Boc-quart.-C), 61.7 (C-9), 55.0 (C-
chain-β-CH2), 1.62 (m, 1 H, 20-H), 1.61 (dd, 1 H, J = 13.6, 5), 51.8 (OMe), 51.4 (Dab-α-CH), 48.4 (C-18), 45.4 (C-8),
13.6 Hz, 190-H), 1.59 (m, 1 H, 6-H), 1.48 (m, 1 H, 60-H), 1.46 44.0 (C-20), 43.2 (C-14), 41.1 (C-19), 38.7 (C-1), 38.2 (C-
(m, 2 H, chain-ζ-CH2), 1.44 (s, 9 H, Boc-CH3), 1.43 (m, 1 H, 4), 37.7 (C-22), 36.9 (C-10), 36.6 (Dab-γ-CH2), 32.8 (Dab-
70-H), 1.41 (m, 1 H, 22-H), 1.37 (s, 3 H, 27-H), 1.32 (m, 4 H, β-CH2), 32.7 (C-7), 31.8 (C-17), 31.1 (C-21), 28.4 (C-29),
chain-δ-CH2 and chain-γ-CH2), 1.31 (m, 2 H, 220-H and 210- 28.3 (C-28), 28.3 (Boc-CH3), 28.2 (C-23), 26.5 (C-16), 26.4
H), 1.30 (m, 2 H, chain-ε-CH2), 1.18 (m, 1 H, 160-H), 1.17 (C-15), 23.5 (C-2), 23.3 (C-27), 18.7 (C-26), 17.3 (C-6), 16.7
(s, 3 H, 25-H), 1.15 (s, 3 H, 29-H), 1.13 (s, 3 H, 26-H), 1.06 (C-24), 16.4 (C-25). – MS (ESI): m/z (%) = 785.3 (26)
(m, 1 H, 10-H), 1.01 (m, 1 H, 150-H), 0.88 (s, 3 H, 24-H), 0.87 [M+H]+, 802.3 (24) [M+NH4]+, 807.5 (100) [M+Na]+,
(s, 3 H, 23-H), 0.81 (s, 3 H, 28-H), 0.80 (m, 1 H, 5-H). – 13
C
823.3 (4) [M+K]+, 1199.9 (14) [3M+2Na]+, 1591.3 (27)
NMR (125 MHz, CDCl3): δ = 200.1 (C-11), 176.9 (C-30), [2M+Na]+. – C45H72N2O9 (785.06): C 68.85, H 9.24, N
173.6 (chain-COO), 169.2 (C-13), 156.0 (Boc-COO), 128.5 3.57; found C 68.69, H 9.43, N 3.44.
(C-12), 80.3 (C-3), 78.6 (Boc-quart.-C), 61.7 (C-9), 55.0 (C-
Methyl (3β)-3-{[N2,N5-bis(tert-butoxycarbonyl)-(L)-
ornithyl]oxy}-11-oxoolean-12-en-30-oate (32)
5), 51.8 (OMe), 48.4 (C-18), 45.4 (C-8), 44.0 (C-20), 43.2
(C-14), 41.0 (C-19), 40.6 (chain-η-CH2), 38.8 (C-1), 38.1
(C-4), 37.7 (C-22), 36.9 (C-10), 34.8 (chain-α-CH2), 32.7
Obtained from 1 by method A as a colorless powder.
(C-7), 31.8 (C-17), 31.1 (C-21), 30.0 (chain-ζ-CH2), 29.1
(chain-δ-CH2), 28.9 (chain-γ-CH2), 28.5 (C-28), 28.4 (Boc-
CH3), 28.3 (C-29), 28.1 (C-23), 26.6 (chain-ε-CH2), 26.4
(C-16), 26.4 (C-15), 25.0 (chain-β-CH2), 23.6 (C-2), 23.3
(C-27), 18.7 (C-26), 17.4 (C-6), 16.8 (C-24), 16.4 (C-25).
– MS (ESI): m/z (%) = 726.4 (84) [M+H]+, 784.5 (100)
[M+Na]+, 1473.5 (37) [2M+Na]+. – C44H71NO7 (726.04):
C 72.79, H 9.86, N 1.93; found C 72.58, H 91, N 1.86.
Yield: 440 mg, 52%. M. p.: 88 – 90 ◦C. – Rf = 0.29 (hexane-
ethyl acetate, 7 : 3). – [α]D = 80.20 (c = 0.55, CHCl3).
– UV/Vis (methanol): λmax(logε) = 249 nm (4.17). – IR
(KBr): ν = 3385br, 2975s, 2872m, 1718s, 1660s, 1514m,
1455m, 1390m, 1366s, 1324m, 1250s, 1217s, 1167s, 1087w,
1049w, 1020w, 985m cm−1. – 1H NMR (500 MHz, CDCl3):
δ = 5.67 (s, 1 H, 12-H), 5.06 (m, 2 H, Orn-NH), 4.56 (dd,
1 H, J = 11.8, 4.8 Hz, 3-H), 4.28 (m, 1 H, Orn-α-CH), 3.69
(s, 3 H, OMe), 3.14 (m, 2 H, Orn-δ-CH2), 2.82 (ddd, 1 H,
J = 13.8, 3.4, 3.4 Hz, 1-H), 2.36 (s, 1 H, 9-H), 2.09 (m, 1 H,
18-H), 2.03 (m, 1 H, 15-H), 2.00 (m, 1 H, 21-H), 1.93 (ddd, 1
Methyl (3β)-3-({2,4-bis[(tert-butoxycarbonyl)amino]-
butanoyl}oxy)-11-oxo-olean-12-en-30-oate (31)
Obtained from 1 by method A as a colorless powder. H, J = 13.1, 4.4, 2.5 Hz, 19-H), 1.87 (m, 1 H, Orn-β-CHH0),
Yield: 670 mg, 54%. M. p.: 117 – 120 ◦C. – Rf = 0.35 1.83 (ddd, 1 H, J = 13.0, 13.0, 4.2 Hz, 16-H), 1.73 (m, 1
(hexane-ethyl acetate, 7 : 3). – [α]D = 70.24 (c = 0.57, H, 2-H), 1.68 (m, 1 H, 7-H), 1.66 (m, 1 H, Orn-β-CHH0),
CHCl3). – UV/Vis (methanol): λmax(logε) = 249 nm (4.06). 1.64 (m, 1 H, 20-H), 1.61 (dd, 1 H, J = 13.6, 13.6 Hz, 190-
– IR (KBr): ν = 3386br, 2976s, 2873m, 1719s, 1660s, H), 1.59 (m, 1 H, 6-H), 1.57 (m, 2 H, Orn-γ-CH2), 1.45 (m,
1513m, 1456m, 1391m, 1367s, 1250s, 1218s, 1166s, 1087w, 1 H, 60-H), 1.44 (s, 18 H, Boc-CH3), 1.42 (m, 1 H, 70-H),
1048w, 1022w, 987m cm−1. – 1H NMR (500 MHz, CDCl3): 1.38 (m, 1 H, 22-H), 1.37 (s, 3 H, 27-H), 1.32 (m, 2 H, 220-
δ = 5.64 (s, 1 H, 12-H), 5.16 (m, 2 H, Dab-NH), 4.53 (dd, H and 210-H), 1.17 (m, 1 H, 160-H), 1.15 (s, 3 H, 25-H),
1 H, J = 11.8, 5.0 Hz, 3-H), 4.34 (m, 1 H, Dab-α-CH), 3.69 1.13 (s, 3 H, 29-H), 1.11 (s, 3 H, 26-H), 1.05 (m, 1 H, 1-
(s, 3 H, OMe), 3.42 (m, 1 H, Dab-γ-CHH0), 3.00 (m, 1 H, H0), 1.02 (m, 1 H, 15-H0), 0.90 (s, 3 H, 24-H), 0.88 (s, 3 H,
Dab-γ-CHH0), 2.82 (ddd, 1 H, J = 13.7, 3.2, 3.2 Hz, 1-H), 23-H), 0.81 (s, 3 H, 28-H), 0.80 (m, 1 H, 5-H). – 13C NMR
2.35 (s, 1 H, 9-H), 2.08 (m, 1 H, 18-H), 2.05 (m, 1 H, 15-H), (125 MHz, CDCl3): δ = 199.9 (C-11), 176.9 (C-30), 172.2
2.01 (m, 1 H, 21-H), 1.92 (ddd, 1 H, J = 13.3, 3.9, 2.5 Hz, (Orn-COO), 169.2 (C-13), 155.9 (Boc-COO), 128.5 (C-12),
19-H), 1.83 (ddd, 1 H, J = 13.1, 13.1, 4.2 Hz, 16-H), 1.73 82.0 (C-3), 79.6 (Boc-quart.-C), 61.6 (C-9), 55.0 (C-5), 53.5
(m, 1 H, 2-H), 1.65 (m, 1 H, 7-H), 1.64 (m, 1 H, 20-H), 1.63 (Orn-α-CH), 51.7 (OMe), 48.4 (C-18), 45.4 (C-8), 44.0 (C-
(m, 1 H, Dab-β-CHH0), 1.61 (dd, 1 H, , J = 13.7, 13.7 Hz, 20), 43.2 (C-14), 41.1 (C-19), 40.0 (Orn-δ-CH2), 38.7 (C-
190-H), 1.58 (m, 1 H, 6-H), 1.59 (m, 1 H, Dab-β-CHH0), 1), 38.1 (C-4), 37.7 (C-22), 36.9 (C-10), 32.7 (C-7), 31.8
1.46 (m, 1 H, 60-H), 1.44 (s, 18 H, Boc-CH3), 1.42 (m, 1 (C-17), 31.1 (C-21), 30.2 (Orn-β-CH2), 28.5 (C-29), 28.4
H, 70-H), 1.38 (m, 1 H, 22-H), 1.36 (s, 3 H, 27-H), 1.31 (m, (Boc-CH3), 28.3 (C-28), 28.1 (C-23), 26.5 (C-16), 26.4 (C-
2 H, 220-H and 210-H), 1.18 (m, 1 H, 160-H), 1.17 (s, 3 H, 15), 26.1 (Orn-γ-CH2), 23.6 (C-2), 23.3 (C-27), 18.7 (C-26),
25-H), 1.15 (s, 3 H, 29-H), 1.13 (s, 3 H, 26-H), 1.02 (m, 1 17.3 (C-6), 16.8 (C-24), 16.3 (C-25). – MS (ESI): m/z (%)
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R. Csuk et al. · Methyl Glycyrrhetinate Esterified with Amino Acids
745
= 799.3 (17) [M+H]+, 816.3 (41) [M+NH4]+, 821.5 (100) (m, 1 H, 160-H), 1.15 (s, 3 H, 25-H), 1.13 (s, 3 H, 29-H), 1.11
[M+Na]+, 837.3 (5) [M+K]+, 1217.8 (6) [3M+K+H]2+ (s, 3 H, 26-H), 1.04 (m, 1 H, 1-H0), 1.00 (m, 1 H, 15-H0), 0.88
1619.3 (28) [2M+Na]+. – C46H74N2O9 (799.09): C 69.14, (s, 3 H, 24-H), 0.86 (s, 3 H, 23-H), 0.80 (m, 1 H, 5-H), 0.79
,
H 9.33, N 3.51; found C 68.96, H 9.51, N 3.42.
(s, 3 H, 28-H). – 13C NMR (125 MHz, CDCl3): δ = 199.9
(C-11), 176.9 (C-30), 172.4 (Lys-COO), 169.2 (C-13), 156.0
(Boc-COO), 128.5 (C-12), 81.9 (C-3), 79.7 (Boc-quart.-C),
61.6 (C-9), 55.0 (C-5), 53.6 (Lys-α-CH), 51.7 (OMe), 48.4
(C-18), 45.4 (C-8), 44.0 (C-20), 43.2 (C-14), 41.1 (C-19),
40.1 (Lys-ε-CH2), 38.7 (C-1), 38.1 (C-4), 37.7 (C-22), 36.9
(C-10), 32.7 (C-7), 32.5 (Lys-β-CH2), 31.8 (C-17), 31.1 (C-
21), 29.6 (Lys-δ-CH2), 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), 22.4 (Lys-γ-CH2), 18.7 (C-26), 17.3 (C-6), 16.8
(C-24), 16.3 (C-25). – MS (ESI): m/z (%) = 813.3 (16)
[M+H]+, 830.2 (18) [M+NH4]+, 835.5 (100) [M+Na]+,
851.3 (4) [M+K]+, 1241.7 (6) [3M+2Na]2+, 1647.1 (10)
[2M+Na]+. – C47H76N2O9 (813.11): C 69.42, H 9.42, N
3.45; found C 69.32, H 9.57, N 3.25.
Methyl (3β)-3-{[N2,N6-bis(tert-butoxycarbonyl)-(L)-
lysyl]oxy}-11-oxoolean-12-en-30-oate (33)
Obtained from 1 by method A as a colorless powder.
Yield: 740 mg, 90%. M. p.: 145 – 148 ◦C (decomp.). – Rf =
0.56 (hexane-ethyl acetate, 7 : 3). – [α]D = 69.88 (c = 0.37,
CHCl3). – UV/Vis (methanol): λmax(logε) = 251 nm (4.05).
– IR (KBr): ν = 3385br, 2976s, 2870m, 1717s, 1660s, 1518s,
1456m, 1391m, 1366s, 1323m, 1250s, 1217s, 1170s, 1087w,
1048w, 1020w, 987m cm−1. – 1H NMR (500 MHz, CDCl3):
δ = 5.64 (s, 1 H, 12-H), 5.06 (m, 2 H, Lys-NH), 4.54 (dd,
1 H, J = 11.7, 4.8 Hz, 3-H), 4.29 (m, 1 H, Lys-α-CH), 3.67
(s, 3 H, OMe), 3.09 (m, 2 H, Lys-ε-CH2), 2.80 (ddd, 1 H,
J = 13.6, 3.6, 3.6 Hz, 1-H), 2.33 (s, 1 H, 9-H), 2.07 (m, 1
H, 18-H), 2.01 (m, 1 H, 15-H), 1.98 (m, 1 H, 21-H), 1.91
(m, 1 H, 19-H), 1.82 (m, 1 H, Lys-β-CHH0), 1.80 (m, 1 H,
Acknowledgement
We like to thank Dr. H. Kommera and PD Dr. R. Paschke
16-H), 1.72 (m, 1 H, 2-H), 1.64 (m, 1 H, Lys-β-CHH0), 1.63 from Biosolutions Halle GmbH for support. We are grate-
(m, 1 H, 7-H), 1.61 (m, 1 H, 20-H), 1.60 (dd, 1 H, J = 13.6, ful to the Stiftung der Deutschen Wirtschaft e.V. (SDW)
13.6 Hz, 190-H), 1.58 (m, 1 H, 6-H), 1.47 (m, 2 H, Lys-δ- for a personal scholarship to Dr. S. Schwarz. The cell lines
CH2), 1.43 (s, 18 H, Boc-CH3), 1.43 (m, 1 H, 60-H), 1.41 were kindly provided by Dr. T. Mu¨ller (Dept. of Haematol-
(m, 1 H, 70-H), 1.40 (m, 1 H, 22-H), 1.35 (s, 3 H, 27-H), 1.35 ogy/Oncology, Universita¨t Halle/Germany). We like to thank
(m, 2 H, Lys-γ-CH2), 1.32 (m, 2 H, 220-H and 210-H), 1.17 “Gru¨nderwerkstatt – Biowissenschaften” for support.
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