Synthesis and Anti-Microbial Activity of Benzylidenhydrazides of Glycyrrethic Acid

Article abstract of DOI:10.1134/S1068162020020065

Abstract: New derivatives of glycyrrhetic acid with hydrazide pharmacophore groups were synthesized and their antimicrobial activity was evaluated. Hydrazide of 3-O-acetyl-N'-(4-hydroxybenzylidene) glycyrrhetic acid exhibited the highest antimicrobial activity. This compound had both an antibacterial effect against Escherichia coli, Proteus vulgaris, Klebsiella pneumonia, Staphylococcus aureus, Citrobacter diversus, Enterobacter aerogenes, Pseudomonas aeruginosa, and Enterobacter cloacae and antifungal activity against the Candida albicans fungus. The minimum inhibitory concentrations of this compound and pimafucin were similar for Candida albicans.

Full text of DOI:10.1134/S1068162020020065

ISSN 1068-1620, Russian Journal of Bioorganic Chemistry, 2020, Vol. 46, No. 2, pp. 246–251. © Pleiades Publishing, Ltd., 2020.
Russian Text © The Author(s), 2020, published in Bioorganicheskaya Khimiya, 2020, Vol. 46, No. 2, pp. 201–206.
Synthesis and Anti-Microbial Activity
of Benzylidenhydrazides of Glycyrrethic Acid
L. A. Baltinaa, 1, R. M. Kondratenkob, and A. K. Bulgakovb
aUfa Institute of Chemistry, Ufa Federal Science Center, Russian Academy of Sciences, Ufa, 450054 Russia
bBashkir State Medical University of the Russian Ministry of Health, Ufa, 450000 Russia
Received August 6, 2019; revised August 23, 2019; accepted October 21, 2019
Abstract—New derivatives of glycyrrhetic acid with hydrazide pharmacophore groups were synthesized and
their antimicrobial activity was evaluated. Hydrazide of 3-O-acetyl-N'-(4-hydroxybenzylidene) glycyrrhetic
acid exhibited the highest antimicrobial activity. This compound had both an antibacterial effect against
Escherichia coli, Proteus vulgaris, Klebsiella pneumonia, Staphylococcus aureus, Citrobacter diversus, Entero-
bacter aerogenes, Pseudomonas aeruginosa, and Enterobacter cloacae and antifungal activity against the Can-
dida albicans fungus. The minimum inhibitory concentrations of this compound and pimafucin were similar
for Candida albicans.
Keywords: glycyrrhetic acid, hydrazides, antimicrobial activity
DOI: 10.1134/S1068162020020065
INTRODUCTION
ganisms and antifungal activity towards a number of
fungi, such as Pythium ultimum, Trichophyton mentag-
rophytes, and Candida albicans [8, 9].
A search for and creation of novel antimicrobial
agents remain urgent problems of modern medicinal
chemistry and microbiology due to a growing resis-
The main pentacyclic triterpenoid which is isolated
tance of pathogenic microorganisms to the known from the extracts of the licorice root is glycyrrhetic
chemotherapeutical drugs and a loss of clinical impor- (glycyrrhetinic) acid (GLA) (I). It is active against
tance of a number of antibiotics. The antibiotic resis- test-microbes of staphylococcal, intestinal, and spore-
tance results in a decrease in the efficacy and duration forming groups [7]. GLA protects against the C. albi-
of a disease treatment, an increase in the number of cans fungi infection on mouse models [8] and staphy-
hospitalization cases, and an increase in species of lococcal pneumonia which is caused by the Staphylo-
bacterial infections which are resistant to treatment coccus aureus bacteria [9].
with known antibiotics [1, 2].
The sodium salt of glycyrrhetinic acid demon-
One of the promising ways of creating new antimi-
crobial preparations is a chemical modification of
structures of known antibiotics and natural com-
pounds, including those isolated from plants [3–6].
strates pronounced antimicrobial activity in vitro
towards S. aureus and mycobacteria [7]. The antibac-
terial effect of sulfonamide derivatives of GLA is found
towards the gram-positive (St. aureus, Bacillus
The main biologically active components of both anthracis, and Corynebacterium bovis) and gram-neg-
the whole extract of licorice root (Glycyrrhiza glabra L. ative (Klebsiella pneumoniae, Proteus vulgaris, and
and Gl. uralensis Fisher) (Leguminosae) and individ- Escherichia coli) bacteria [7]. However, the GLA applica-
ual natural substances which are isolated from the tion as a basic structure (scaffold) to the synthesis of its
extract are shown to exhibit various biological and biologically active derivatives and their structure-func-
pharmacological activities, in particular antiviral, tional relationships are still little studied.
antitumor, anti-inflammatory, antiulcer, antioxida-
The goal of this study is the synthesis of a number
tive, hepatoprotective, antimicrobial, and others [7].
of nitrogen-containing derivatives of GLA with their
Extracts of the licorice roots and their components
carboxyl functions that are modified with hydrazide
have the antimicrobial activity towards a number of
pharmacophore groups and evaluation of the antimi-
gram positive and gram negative pathogenic microor-
crobial and antifungal activity of these derivatives
towards a panel of strains of the gram positive and
Abbreviations: GLA, glycyrrhetic acid; BEB, beef-extract broth;
gram negative bacteria and fungi. The antimicrobial
properties of this group of the GLA derivatives are not
described in the literature.
MIC, minimum inhibiting concentration.
1 Corresponding author: phone: +7 (917) 424-68-12; e-mail:
baltina@anrb.ru.
246

SYNTHESIS AND ANTI-MICROBIAL ACTIVITY OF BENZYLIDENHYDRAZIDES
247
1H NMR spectra of compounds (V)–(IX). The reso-
RESULTS AND DISCUSSION
nances from aromatic carbon atoms (132.2–111.0 ppm)
The starting GLA hydrazide (IV) (Scheme 1) was
prepared by the treatment of the synthesized chloride
of 3-O-acetate of glycyrrhetic acid (III) with hydra-
zine hydrate in methylene chloride (the yield was 75%)
[7]. Benzylidenehydrazides (V)–(IX) were prepared
by boiling of acylhydrazide (IV) with aromatic alde-
hydes in ethanol for 6 h with the yields of 70–75%.
1
were observed in the 13C NMR spectra. The H
(500 MHz) and 13C NMR spectra of compounds (IV),
(VI), and (VII) were recorded with a high resolution.
A complete attribution of the resonances from protons
and carbon atoms was performed. The protons of
ОСН3-group of the aromatic residues were found in
Structures of compounds (V)–(IX) were confirmed by the 1H NMR spectra of compounds (VI) and (VII) at
IR spectra, 1H and 13C NMR spectra, and the element
analysis. The additional resonances from protons of
CONH– and N=СН-groups and aromatic protons
3.88 and 3.86 ppm, respectively. The N=CH protons
were placed in a low field (8.88–8.76 ppm). The pro-
tons of N(CH3)-group were observed in the spectrum
(9.9–7.3 ppm) were present in the low-field area of the of compound (IX) at 3.07 and 2.99 ppm, respectively.
COOH
COCl
CONHNH2
O
O
O
a
b
RO
AcO
AcO
(I) R = H
(II) R = Ac
(III)
(IV)
CONHNCHR
(V) R =
c
O
OMe
OH
(VI) R =
(VII) R =
AcO
MeO
(VIII) R =
N(CH3)2
(IX) R =
The reaction conditions: (a) SOCl2, benzene; (b) NH2NH2, CH2Cl2; (c) RCHO, EtOH, 78°C, 6 h
Scheme 1.
The antimicrobial activity of GLA and its deriva- matic groups resulted in an increase in the antimicro-
tives was tested towards the St. aureus, K. pneumoniae,
E. coli, Ps. aeruginosa, Pr. vulgaris, Citrobacter diver-
sus, Ent. aerogenes, and Ent. cloacae gram-positive and
gram-negative bacteria and the C. albicans pathogenic
fungi [10, 11]. The Ceftriaxone antibiotic (Shreya,
India) and the Pimafucin antifungal agent (Astellas,
the Netherlands) were used as comparison medicines.
The data on the antimicrobial activity of the examined
compounds were given in Table 1.
bial activity of the prepared benzilidenehydrazidies.
GLA and N'-(4-hydroxybenzilidenehydrazide) (VIII)
exhibited the maximum antimicrobial activity. Com-
pound (VIII) had both the antibacterial effect towards
the all studied gram positive and gram negative bacte-
ria and the antifungal activity against the C. albicans
pathogenic fungi, suggesting a wide spectrum of its
action. The value of the minimum inhibiting concen-
tration (MIC) towards the tested bacteria proved to be
higher for GLA and compound (VIII) than that for the
The results demonstrated that the modification of
hydrazide (IV) by the introduction of different aro- Ceftriaxone comparison antibiotic. MIC towards the
RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY Vol. 46 No. 2 2020

248
BALTINA et al.
Table 1. The antimicrobial (bacteriostatic and fungistatic) activity of GLA and its derivatives
Minimum inhibiting concentration (MIC) (mg/mL)
Compound
Ec
Рv
Кp
Sa
Сd
Еa
Рa
Ecl
Сa
GLA (I)
(IV)
(V)
(VI)
(VII)
(VIII)
(IX)
Ceftriaxone
Pimafucin
0.1
>10
0.1
>10
0.1
>10
0.1
>10
0.1
>10
0.1
>10
0.1
>10
0.1
>10
1.0
>10
10
1.0
1.0
0.001
10
0.05
1.0
1.0
1.0
0.1
1.0
0.5
–
1.0
1.0
1.0
0.1
1.0
0.05
–
1.0
1.0
1.0
0.1
1.0
0.05
–
1.0
1.0
1.0
0.1
1.0
0.5
–
1.0
1.0
1.0
0.1
1.0
0.05
–
1.0
1.0
1.0
0.1
1.0
0.05
–
1.0
1.0
1.0
0.1
1.0
0.05
–
1.0
1.0
1.0
0.1
1.0
–
–
0.001
The following abbreviations are used in the table: Ec, Escherichia coli; Pv, Proteus vulgaris; Kp, Klebsiella pneumoniae; Sa, Staphylococcus
aureus; Cd, Citrobacter diversus; Ea, Enterobacter aerogenes; Pa, Pseudomonas aeruginosa; Ecl, Enterobacter cloacae; Ca, Candida albi-
cans. The average results of two measurements of MIC are given.
С. albicans fungi was the same (0.001 mg/mL) for
TLC was carried out on Sorbfil plates (Sorbopo-
compound (VIII) and Pimafucin. The MIC values of limer, Russia) in the chromatographic system A (ben-
zene–ethanol = 10 : 1). The substances were identified
by the treatment with a 5% solution of Н2SO4 in ethanol
and subsequent heating to 120–125°C for 2–3 min. Sil-
ica gel KSK (the 50–150 fraction according to the dry
classification, Sorbopolimer) was used for column
chromatography. The solvents were purified according
hydrazides (V)–(VII) proved to be much higher than
the corresponding value for GLA and compound
(VIII) (1 mg/mL) in all the cases. The starting hydra-
zide (IV) was inactive (MIC >10 mg/mL) towards
both the tested bacteria and fungi. Thus, the introduc-
tion of benzylidenehydrazide pharmacophore groups
in position C30 of GLA considerably influenced the to the known techniques [14]. The solvents were evap-
antimicrobial activity of the compounds. The most orated in vacuum at 40–45°C. GLA (I) was prepared
active compound (VIII) would be promising for fur- by hydrolysis of glycyrrhizic acid by the procedure [7];
mp 293–295°С, 20 + 163° (с 0.04, CHCl3). The lit-
ther studies as an antimycotic agent.
[α]D
20
erature data [7]: mp 290–292°С,
+ 165° (с 0.04,
[α]D
CHCl3). 3-O-Acetate of GLA (II) was synthesized by
EXPERIMENTAL
the treatment of GLA with acetic anhydride in pyri-
1
13
α 2D0
]
The Н and С NMR spectra were recorded on a
Brüker Avance-III impulse spectrometer (Germany)
with the working frequency of 500.13 (1Н) and 125.47
(13C) MHz or a Bruker АМХ-300 spectrometer (Ger-
many) with the working frequency of 300 (1Н) and
75.5 (13С) MHz in CDCl3. Chemical shifts were
expressed in ppm relatively to the resonance from the
internal standard (tetramethylsilane). The constants
of spin-spin interaction (J) were expressed in Hz. The
resonances in the NMR spectra were attributed using
the standard software for the Bruker Avance-III spec-
trometer and the literature data for the GLA deriva-
tives and benzalhydrazides of betulinic acid [12, 13].
The IR spectra were recorded on an IR Prestige-21
spectrophotometer (Shimadzu, Japan) in a paste with
vaseline oil. The optical activity was measured on a
PerkinElmer 341 polarimeter (United States) in a 1-
decimetre tube at 20–22°C (λNa 546 nm). Melting
points were determined on a Boetius microstage (Ger-
many) and were not corrected. The element analysis
dine [7]; mp 315–317°С,
+ 165° (c 0.4; CHCl3).
[
20
The literature data [7]: mp 317–321°С,
+ 140–
[α]D
145° (CHCl3). Chloride of 3-O-acetyl-GLA (III) was
prepared by the treatment of compound (II) with SOCl2
in benzene and used without any further purification [7].
Hydrazide of 3-O-acetyl-glycyrrhetic acid (IV).
85% Hydrazine hydrate (11.0 mL, 36 mmol) was
added dropwise to the solution of chloride of 3-O-ace-
tyl-GLA (III) (2.0 g, 3.8 mmol) in methylene chloride
(50 mL) on stirring and cooling in an ice-bath (0–
5°С). The reaction mixture was stirred for 1 h, washed
with 5% solution of NaHCO3 (100 mL) and water
(100 mL), dried over MgSO4, and evaporated. The
residue was fractionated on a column with silica gel
which was eluted with the mixtures of benzene and
ethanol (300 : 1, 200 : 1, and 100 : 1; v/v). The yield of
20
compound (IV) was 1.5 g (75%); R 0.60 (А).
+
[α]D
f
175° (с 0.04, СН2Сl2); IR (ν, cm–1): 3387 (NH), 1733
1
was performed on a Hekatech CHNS-analyzer (Ger- (OAc), 1658 (C11=O); Н NMR (500 MHz ): 8.52
many).
(1Н, broadened s, CONH), 5.53 (1H, s, H12), 4.50
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SYNTHESIS AND ANTI-MICROBIAL ACTIVITY OF BENZYLIDENHYDRAZIDES
249
(1H, dd, J 11.6 and 4.5, H3), 2.80 (1H, dd, J 10.6 and %: С 75.95, Н 8.72, N 4.42. Calc. %: С 76.18, Н 8.85,
N 4.56. m/z 614.83 [М+].
N'-(4-Methoxybenzylidene)hydrazide of 3-О-ace-
toxy-18βН-olean-12-en-11-on-30-ic acid (VI). The
3.4, H18), 2.32 (1H, m, Н1b), 2.31 (1Н, s, Н9), 2.18
(1Н, dt, J 12.8 and 2.5, H1a), 2.06 (3H, s, COCH3),
2.05–1.85 (3H, m, Н16b, H2b), 1.80 (1H, td, J 13.7
and 4.1, H2a), 1.70–1.52 (7H, m, 2Н6, Н19b, H15b,
H21b, and H22b), 1.50–1.30 (7H, m, Н7а, Н15а, Н16а,
Н19а, Н22а, and NH2), 1.31 (3H, s, C27Н3), 1.25 (3H,
s, C26H3), 1.12 (3H, s, C25H3), 1.09 (3H, s, C29H3),
1.00 (1Н, m, Н21а), 0.88 and 0.87 (6H, 2 s, С23Н3,
20
yield of compound (VI) was 0.22 g (70%); R 0.52,
+
[α]D
f
152° (c 0.05, СНCl3); IR (ν, cm–1): 3360 (NH), 1729
(Ac), 1658 (C11=O), 1596, 1588 (C6H4); Н NMR
1
(500 MHz): 9.83 and 8.76 (2H, both broadened s,
CONH, N=CH), 8.01 and 7.83 (2Н, both d, J 8.6,
Н2', Н6'), 7.01 and 6.90 (2Н, both d, J 8.9, Н3', Н5'),
13
С24Н3), 0.80 (1Н, m, Н5), 0.75 (3Н, s, С28Н3); С
NMR (125 MHz, ): 200.1 (С11), 174.8 (С30), 171.0 5.65 (1Н, s, Н12), 4.50 (1Н, dd, J 11.8 and 4.5, Н3),
(СОСН3), 170.0 (С13), 127.9 (С12), 80.6 (С3), 61.7 3.88 (3Н, s, ОСН3), 2.75 (1Н, dd, J 11.6 and 3.5,
(С9), 55.0 (С5), 48.6 (С18), 45.4 (С20), 43.3 (С14), Н18), 2.29 (1Н, s, Н9), 2.17 (1Н, dd, J 12.3 and 3.3,
43.2 (С8), 40.7 (С19), 38.8 (С1), 38.0 (С4), 37.4
(С22), 36.9 (С10), 32.7 (С7), 31.8 (С17), 31.3 (С21),
29.0 (С29), 28.5 (С38), 28.0 (С28), 26.5 (С16), 26.2
(С15), 23.5 (С2), 23.3 (С27), 21.4 (СОСН3), 18.9
(С26), 17.3 (С6), 16.6 (С24), 16.1 (С25).
'
Н1 ), 2.01 (3H, s, COCH ), 2.00–1.90 (4H, m,
H1a,
Н2bb, and H16b), 1.73 (1H, td, J 13.1 and 4.5, Н2а),
1.70–1.50 (7Н, m, 2Н6, Н7b, H19b, H15b, H21b, and
H22b), 1.45–1.30 (5H, m, Н7а, Н15а, Н16а, Н22а, and
Н19а), 1.29 (3Н, s, С27Н3), 1.23 (3Н, s, С26Н3), 1.21
(3Н, s, С25Н3), 1.15 (3Н, s, С29Н3), 1.05 (3Н, s,
С28Н3), 0.95 (1Н, m, Н21а), 0.83 and 0.81 (6Н, both
3
Found for C32H50O4N2, %: С 72.65, Н 9.52, N 5.22.
Calc. %: С 72.96, Н 9.67, N 5.32. m/z 526.73 [М+].
s, С23Н3 and С24Н3), 0.75 (1Н, m, Н5); С NMR
13
The General Procedure for Preparation
of N'-Benzylidenehydrazides (V)–(IX)
(75.5 MHz): 200.0 (С11), 174.7 (С30), 171.0
(СОCH3), 169.8 (С13), 164.5 and 159.5 (N=CH,
C4’), 131.9–114.3 (С1'–C3', C5', C6', C12), 80.6
(С3), 61.7 (С9), 55.5 and 55.0 (C5, ОСН3), 48.4
(С18), 45.4 (С20), 43.3 (С14), 43.2 (С8), 40.8 (С19),
38.8 (С1), 38.0 (С4), 37.4 (С22), 36.9 (С10), 32.7
(С7), 31.8 (С17), 31.3 (С21), 29.0 (С29), 28.5 (С23),
28.0 (С28), 26.5 (С16), 26.2 (С15), 23.5 (C2), 23.3
(С27), 21.3 (СOCН3), 18.9 (С26), 17.3 (С6), 16.6
(С24), 16.1 (С25).
The mixture of hydrazide (IV) (0.26 g, 0.5 mmol) and
the corresponding aromatic aldehyde (0.5–0.6 mmol) in
ethanol (10 mL) was boiled for 6 h and diluted with the
1% solution of hydrochloric acid (10 mL). The precip-
itate was filtered, washed with water, dried, and frac-
tionated on a column with silica gel which was eluted
with benzene and the mixtures of benzene and ethanol
(300 : 1, 200 : 1, and 100 : 1; v/v). The fractions that
were individual according to TLC were combined and
evaporated.
Found for C40H56N2O6, %: C 74.30, H 8.64, N
4.22. Calc. %: C 74.49, H 8.76, N 4.34. М 644.86.
N'-(3-Methoxybenzylidene)hydrazide of 3-О-ace-
N'-Benzylidenehydrazide of 3-acetoxy-18βН-
olean-12-en-11-on-30-ic acid (V). The yield of com- toxy-18βН-olean-12-en-11-on-30-ic acid (VII). The
20
yield of compound (VII) was 0.24 g (75%); Rf 0.65 (А);
[ ]
α 2D0
+ 146° (с 0.08, CHCl3); IR (ν, cm–1): 3214 (NH),
pound (V) was 0.22 g (72%); R 0.60 (А);
+ 144°
[α]D
f
(с 0.06, CHCl3); IR ( ν, cm–1): 3330 (NH), 1729 (Ac),
1727 (Ас), 1658 (C11=O), 1609, 1600, 1586 (C6H4); 1Н
NMR (500 MHz): 9.97 and 8.88 (2Н, both s, CONН,
N=CH), 7.69 (1H, d, J 7.7, H6''), 7.60 (1H, s, H2'),
7.45 (1H, d, J 7.5, H4'), 7.35 (1H, t, J 7.9, H5'), 7.14
(1H, d, J 7.8, H3'), 5.70 (1H, s, H12), 4.50 (1H, dd, J
11.5 and 4.7, Н3), 3.86 (3Н, s, ОСН3), 2.78 (1Н, dd, J
13.3 and 3.4, Н18), 2.30 (1Н, s, Н9), 2.18 (1H, m,
Н1b), 2.04 (3H, s, COCH3), 2.00–1. 93 (3Н, m, Н1а,
H2b, and Н16b), 1.77 (1Н, td, Н2а, J 13.3 and 4.4),
1.70–1.50 (7Н, m, 2Н6, Н7b, H19b, H15b, H21b, and
H22b), 1.45–1.30 (5H, m, Н7а, Н15а, Н16а, Н19а, and
1652 (C11=O), 1647, 1620 (C6H5); 1Н NMR
(300 MHz): 8.95 and 8.50 (2Н, both broadened s,
СОNH, N=CH), 7.54–7.26 (5Н, m, С6Н5), 5.67
(1H, s, H12), 4.52 (1Н, m, Н3), 2.04 (3Н, s,
СОСН3), 1.85–1.1.50 (m, СН and СН2 in the penta-
cyclic skeleton), 1.30 (3H, s, C27H3), 1.25 (6H, s,
C26H3 and C25H3), 1.17 (3H, s, C29H3), 1.00 (3H, s,
С28Н3), 0.86 (6H, s, C23H3 and С24Н3), 0.73 (3Н, s,
С28Н3); 13С NMR (75.5 MHz): 200.2(С11), 175.0
(С30), 171.1 (COCH3), 170.1 (C13), 149.0 (N=CH),
130.0–122.0 (С1'–С6', С12), 80.6 (С3), 61.6 (С9),
55.0 (С5), 48.4 (С18), 45.4 (С20), 43.3 (С14), 43.2
(С8), 40.7 (С19), 38.8 (С1), 38.0 (С4), 37.4 (С22),
36.8 (С10), 32.7 (С7), 31.9 (С17), 31.2 (С21), 29.2
Н22а), 1.32 (3Н, s, С27Н3), 1.25 (3Н, s, С26Н3), 1.15
(3Н, s, С25Н3), 1.08 (3Н, s, С29Н3), 0.86 and 0.84
(6Н, both s, С23Н3 and С24Н3), 0.79 (1Н, m, Н5), 0.75
13
(С29), 28.4 (С23), 28.0 (С28), 26.4, 26.3 (C16, С15), (3Н, s, С28Н3); С NMR (125 MHz): 200.0 (С11),
23.5 (С2), 23.3 (С27), 21.8 (COCH3), 18.7 (С26), 17.3
(С6), 16.6 (С24), 16.3 (С25). Found for С39Н54N2O4,
175.2 (С30), 171.0 (СОСН3), 169.7 (С13), 160.2 and
159.6 (N=CH, С3'), 130.9–114.5 (С1', С2', С4'–С6',
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BALTINA et al.
and C12), 80.7 (C3), 61.7 (C9), 55.4 and 55.1 (C5, 23.6 (C2), 23.3 (C27), 21.3 (CH3), 18.76 (C26), 17.4
OCH3), 48.3 (C18), 45.4 (C20), 43.3 (C14), 43.2
(C8), 40.9 (C19), 38.8 (C1), 38.0 (C4), 37.4 (C22),
36.9 (C10), 32.7 (C7), 31.8 (C17), 31.5 (C21), 29.0
(C29), 28.5 (C23), 28.0 (C28), 26.5 (C16), 26.3 (C15),
23.5 (C2), 23.3 (C27), 21.2 (COCH3), 18.8 (C26), 17.3
(C6), 16.6 (C24), 16.2 (C25). Found for C40H56N2O5,
%: С 74.25, Н 8.73, N 4.25. Calc. %: C 74.49, H 8.76,
N 4.34. М 644.86.
N'-(4-Hydroxybenzylidene)-hydrazide of 3-О-ace-
toxy-18βН-olean-12-en-11-on-30-ic acid (VIII). The
yield of compound (VIII) was 0.23 g (74%); Rf 0.55
20
(C6), 16.7 (C24), 16.3 (C25). Found for С39Н57N3O4,
%: С 73.91; Н 8.82; N 6.50. Calc. %: С 74.13, H 9.09,
N 6.65. M 631.86.
Examination of the Antimicrobial Activity
of the Compounds
The following deposited strains of microorganisms
of the Tarasevich State Research Institute of Stan-
dardization and Control of Medicinal Biological
Preparations and the Museum of the Department of
Microbiology and Virology (GBOU VPO BGMY) of
the Russian Health Ministry were used in this study:
Escherichia coli, Proteus vulgaris, Klebsiella pneumo-
niae, Staphylococcus aureus, Citrobacter diversus,
Enterobacter aerogenes, Pseudomonas aeroginosa,
Enterobacter cloacae, and Candida albicans.
The antimicrobial activity of the tested compounds
was determined by the method of “diffusion in agar”
and the tenfold serial dilutions in the beef-extract
broth (BEB) according to [10, 11]. The tested com-
pound (100 mg) was preliminary dissolved in DMSO
(1 mL) and further diluted with BEB to the working
concentration of 10 mg/mL. The examined cultures of
the microorganisms were added to a number of tubes
with the tested compounds taken in the subsequent
tenfold-decreasing concentrations in BEB. The
microbial load was 2.0 × 106 of the microbial bodies
per 1 mL of the culture medium. The tubes were incu-
bated for 72 h at 37°С and for 48 h at 25°С. Growth of
the test cultures was visually evaluated. The MIC data
were expressed as the average values of two measure-
ments. Ceftriaxone (Shreya, India) and Pimafucin
(Astellas, the Netherlands) were used as the compari-
son medicines.
(А);
+ 162° (c 0.04, CHCl3); IR (ν, cm–1): 3408
[α]D
(NH), 1733 (Ac), 1661 (C11=O), 1620, 1604 (C6H5);
1Н NMR (300 MHz, CDCl3, δ, ppm): 9.82 and 8.85
(2H, both s, CONH, N=CH), 7.75–6.98 (4H, m,
Н2', H3', H5', and Н6'), 5.65 (1H, s, H12), 4.51 (1H,
dd, J 11.1 and 4.6, Н3), 2.83 (1Н, d, J 12.9, H18), 2.30
(1H, s, H9), 2.04 (3H, s, COCH3), 1.90–1.36 (СН
and СН2 in the pentacyclic skeleton, m), 1.31 (3Н, s,
С27Н3), 1.27 (3Н, s, С26Н3), 1.16 (3Н, s, С25Н3), 1.08
(3Н, s, С29Н3), 0.86 and 0.84 (6Н, s, С23Н3 and
С24Н3), 0.72 (3Н, s, С28Н3); С NMR (75.5 MHz):
13
200.3 (С11), 175.0 (С30), 171.1 (СОCH3), 170.1
(С13), 162.8 and 159.9 (N=CH, C4'), 132.2–116.1
(C1'–C3', C5', C6', and C12), 80.7 (С3), 61.7 (С9),
55.1 (С5), 48.5 (С18), 45.5 (С20), 43.4 (С14), 43.2
(С8), 40.8 (С19), 38.8 (С1), 38.0 (С4), 37.4 (С22),
36.9 (С10), 32.7 (С7), 31.8 (С17), 31.3 (С21), 29.1
(С29), 28.5 (С23), 28.1 (С28), 26.5 (С16), 26.2 (С15),
23.5 (C2), 23.3 (С27), 18.9 (С26), 17.3 (С6), 16.6, 16.1
(С24, C25).
Found for C40H54N2O5, %: С 74.19, Н 8.62, N
4.26. Calc. %: C 74.25, H 8.63, N 4.44. М = 630.83.
m/z, 631.5 [M + H]+, 629.5 [M – H]–.
N'-(4,4-Dimethylamino-benzylidene)hydrazide of
FUNDING
3-О-acetoxy-18βН-olean-12-en-11-on-30-ic
acid
This study was performed within the framework of proj-
ect no. АААА-А17-11701191025-6 with the use of the
equipment of TsPK Khimiya.
(IX). The yield of compound (IX) was 0.23 g (72%); Rf
20
0.58 (А);
+150° (c 0.07, CHCl3). IR (ν, cm–1):
[α]D
3408 (NH), 1733 (Ac), 1662 (C11=O), 1620, 1599
(Ph); Н NMR (300 MHz): 9.73 and 8.55 (2Н, s,
1
COMPLIANCE WITH ETHICAL STANDARDS
CONH, N=CH), 7.74–6.67 (2H, m, H2', H3', H5',
and H6'), 5.71 (1H, s, H12), 4.49 (1H, dd, J 11.0 and
4.0, Н3), 3.07 and 2.99 (6H, both s, N(CH3)2), 2.04
(3H, s, COCH3), 1.80–1.50 (m, СН and СН2 in the
This article does not contain any studies involving
human participants and animals performed by any of the
authors.
pentacyclic skeleton), 1.36 (3Н, s, С27Н3), 1.22 (3Н, s,
С26Н3), 1.15 (3Н, s, С25Н3), 1.10 (3Н, s, С29Н3), 0.88
Conflict of Interests
13
(6Н, s, С23Н3 and С24Н3), 0.80 (3Н, s, С28Н3); С
The authors declare that they have no conflicts of interest.
NMR (75.5 MHz): 200.1 (С11), 174.8 (С30), 171.0
(СОСН3), 169.4 (С13), 154.4, 144.5 (N=CH, С4'),
132.0–111.0 (C1'–C3' and C12), 80.7 (C3), 61.7 (C9),
55.0 (C5), 48.1 (C18), 45.4 (C20), 43.3 (C14), 43.2
(C8), 40.1 (C19), 38.8 (C1), 38.0 (C4), 37.4 (C22),
36.9 (C10), 32.7 (C7), 31.8 (C17), 31.3 (C21), 29.2
(C29), 28.5 (C23), 28.1 (C28), 26.5 (C16), 26.4 (C15),
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Translated by L. Onoprienko
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