Synthesis and Antibacterial Activity of Benzenesulfonylhydrazone Derivatives of Methyl Dehydroabietate

Article abstract of DOI:10.1134/S1070363219040297

Six benzenesulfonylhydrazone derivatives of methyl dehydroabietate are synthesized via esterification, benzylic oxidation, condensation with hydrazine hydrate, and following nucleophilic substitution reaction with a variety of substituted benzenesulfonyl chloride. The structures of the synthesized compounds are characterized by ¹H NMR and MS spectra. Antibacterial activity of the target compounds is evaluated by disk diffusion method against E. coli, S. aureus, and B. subtilis. The results demonstrate that benzenesulfonylhydrazone derivatives of methyl dehydroabietate exhibit inhibitory activity. Among the six compounds, p-fluorobenzenesulfonylhydrazone of methyl dehydroabietate exhibits the highest antibacterial activity with the zone of inhibition of 17.3 mm against B. subtilis and 16.5 mm against S. aureus.

Full text of DOI:10.1134/S1070363219040297

ISSN 1070-3632, Russian Journal of General Chemistry, 2019, Vol. 89, No. 4, pp. 819–823. © Pleiades Publishing, Ltd., 2019.
Synthesis and Antibacterial Activity of Benzenesulfonylhydrazone
Derivatives of Methyl Dehydroabietate
Zhi Zhoua*, Xiang Wanga, and Tingting Zhoub
a School of Life and Health Science, Kaili University, Kaiyuan Road 3, Kaili, Guizhou, 556011 China
*e-mail: zhou86zhi@163.com
b Clinical Laboratory, Yuping Dong Autonomous County People’s Hospital,
Renmin Road 343, Yuping, Guizhou, 554000 China
Received January 25, 2019; revised March 22, 2019; accepted March 24, 2019
Abstract—Six benzenesulfonylhydrazone derivatives of methyl dehydroabietate are synthesized via
esterification, benzylic oxidation, condensation with hydrazine hydrate, and following nucleophilic substitution
reaction with a variety of substituted benzenesulfonyl chloride. The structures of the synthesized compounds
1
are characterized by H NMR and MS spectra. Antibacterial activity of the target compounds is evaluated by
disk diffusion method against E. coli, S. aureus, and B. subtilis. The results demonstrate that
benzenesulfonylhydrazone derivatives of methyl dehydroabietate exhibit inhibitory activity. Among the six
compounds, p-fluorobenzenesulfonylhydrazone of methyl dehydroabietate exhibits the highest antibacterial
activity with the zone of inhibition of 17.3 mm against B. subtilis and 16.5 mm against S. aureus.
Keywords: methyl dehydroabietate, benzenesulfonylhydrazone, sythesis, antibacterial
DOI: 10.1134/S1070363219040297
INTRODUCTION
methyl dehydroabietate 5a–5f (Scheme 1) from
dehydroabietic acid via esterification, benzylic
oxidation, and condensation with hydrazine hydrate,
followed by nucleophilic substitution reactions with a
variety of benzenesulfonyl chloride derivatives.
Dehydroabietic acid 1, a natural occurring diterpene
resin acid, can be extracted from Pinus rosin or
commercial disproportionated rosin. Dehydroabietic
acid and its derivatives have been reported to possess a
broad spectrum of biological activities including
antimicrobial [1–3], antiviral [4], antitumor [5–7],
antiulcer [8], antiinflammatory [9], and BK channel-
opening [10]. Effective biological activity of
dehydroabietic acid and its derivatives prompted us to
search for new rosin acid derivatives. Li et al [11]
synthesized a series of dehydroabietic acid derivatives
bearing an acylhydrazone moiety by condensation of
dehydroabietic acylhydrazide with a variety of
substituted arylaldehydes, many products showed
moderate to high levels of anticancer activity. Gu et al
[12] synthesized N-acylhydrazone derivatives by the
reactions of dehydroabietic acid hydrazide with a
variety of substituted arylaldehydes. Several
accumulated products exhibited the pronounced anti-
bacterial activities.
The synthesized products were tested for their
antibacterial activity.
RESULTS AND DISCUSSION
As presented in Scheme 1, dehydroabietic acid 1
was esterified by MeOH in the presence of SOCl2 with
formation of compound 2. Oxidation of the inter-
mediate 2 by an excess of t-BuOOH (8 equiv.) and
CrO3/pyridine mixture in CH2Cl2 [13] gave C7
benzylic oxidation product 3. The following reaction
of the intermediate 3 with hydrazine hydrate yielded
the corresponding methyl 7-oxodehydroabietate hydra-
zone 4. Treatment of the mixture of compound 4 with
Et3N by a solution of one of substituted benzene-
sulfonyl chlorides in dry THF led to the corresponding
target products 5a–5f.
Antibacterial activity. The accumulated data of
antimicrobial activity of the synthesized compounds by
the diffusion method (see the table) indicated their
inhibitory activity against E. coli, S. aureus, and B.
These studies highlighted the value of dehydro-
abietic acid as a starting points for the development of
new antimicrobial agents. In this paper, we report the
synthesis of benzenesulfonylhydrazone derivatives of
819

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ZHI ZHOU et al.
Scheme 1.
b
a
O
COOH
COOCH3
COOCH3
1
3
2
O
R
S
Cl
R
c
O
H
N
NNH2
N
S
d
COOCH3
O O
COOCH3
5
4
R = CH3 (5a), OCH3 (5b), NO2 (5c), F (5d), CF3 (5e), Br (5f). Reagents and conditions: a, SOCl2, benzene, MeOH, reflux;
b, t-BuOOH, CrO3, pyridine, CH2Cl2, room temperature; c, NH2NH2·H2O, EtOH, reflux; d, THF, Et3N, room temperature.
subtilis bacterial strain. p-Nitrobenzenesulfonyl-
hydrazone of methyl dehydroabietate 5c and p-fluoro-
benzenesulfonylhydrazone of methyl dehydroabietate
5d exhibited relatively highly inhibitory activity
against two bacterial strains, including B. subtilis and
S. aureus. Among the six compounds, the product 5d
demonstrated the highest antibacterial activity against
B. subtilis and S. aureus.
according to the standard procedures. Column
chromatography was performed on silica gel (ZCXII,
~100–200 mesh). Chemical reactions were monitored
by TLC using precoated silica gel GF254 plates.
Melting points were determined on a RY-1G melting
point apparatus and were uncorrected. NMR spectra
were measured on a Bruker AVANCE AV-500
spectrometer using CDCl3 as the solvent and TMS as
the internal standard. ESI mass spectra were measured
on an Agilent 1100 Capillary LC/Micromass Q-TOF
micromass spectrometer. Microanalytical data were
obtained on an Elementar Vario EL III elemental
analyzer.
EXPERIMENTAL
All chemicals and solvents were obtained from
commercial sources and used as received or dried
Antibacterial activity of compounds 5a–5f determined by
the diffusion method
(1R,4aS)-Methyl 1,2,3,4,4a,9,10,10a-octahydro-7-
isopropyl-1,4a-dimethylphenanthrene-1-carboxylate
(2). To a solution of dehydroabietic acid (10 g,
33.28 mmol) in benzene (80 mL) was added slowly
SOCl2 (5.96 g). The mixture was stirred and refluxed
for 3 h. After cooling down, the solvent and excess of
SOCl2 were evaporated in vacuum to yield the yellow
oily compound. MeOH (40 mL) Was added to it, and
the mixture was refluxed for 2 h then cooled down to
room temperature and concentrated in vacuum. The
product was recrystallized from ethanol as a white
Zone of inhibition, mm
Compound
E. coli
S. aureus B. subtilis
5a
7.0
8.1
9.8
8.9
7.7
5b
8.1
5c
12.3
13.0
12.1
11.6
23.6
13.9
16.5
13.2
12.4
24.2
15.1
17.3
14.7
10.1
22.7
5d
5e
5f
1
solid. Yield 84.4%, mp 63–65°C. H NMR spectrum,
δ, ppm: 7.15 d (J = 8.2 Hz, 1H), 6.98 d.d (J = 8.2,
1.5 Hz, 1H), 6.87 d (J = 1.5 Hz, 1H), 3.65 s (3H), 2.92–
Chloramphenicol
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SYNTHESIS AND ANTIBACTERIAL ACTIVITY OF BENZENESULFONYLHYDRAZONE
821
2.81 m (3H), 2.31 d (J = 12.3 Hz, 1H), 2.25 d.d (J =
12.4, 2.1 Hz, 1H), 1.71–1.60 m (5H), 1.58 s (3H), 1.51
m (1H), 1.43 m (1H), 1.27 s (3H), 1.23 d (J = 7.1 Hz,
6H). MS, m/z: 314.2 [M]+. Found, %: C 80.28; H 9.57.
C21H30O2. Calculated, %: C 80.21; H 9.62.
at room temperature, concentrated to approximately
15 mL under reduced pressure and cooled in an ice
bath. The resulting precipitate was filtered off and
washed with distilled water to give the crude product,
which was recrystalized from ethanol to afford the
corresponding compound 5a–5f.
(1R,4aS)-Methyl 1,2,3,4,4a,9,10,10a-octahydro-7-
isopropyl-1,4a-dimethyl-9-oxophenanthrene-1-car-
boxylate (3). To a suspension of CrO3 (135 mg,
0.135 mmol) in CH2Cl2 (200 mL) were added 65% t-
BuOOH (34.8 mL, 216.9 mmol) and pyridine
(0.22 mL, 2.72 mmol). The mixture was stirred for
3 min at room temperature, then compound 2 (8.52 g,
27.11 mmol) was added to it. After 25 h of stirring the
mixture at room temperature it was treated with 5%
NaOH (2×60 mL) and brine (2×60 mL), dried over
anhydrous Na2SO4 and concentrated in vacuum. The
residue was purified by column chromatography
(petroleum ether/eacetone, 100:1) to give compound 3
(1R,4aS)-Methyl 9-(p-tosylhydrazono)-1,2,3,4,4a,-
9,10,10a-octahydro-7-isopropyl-1,4a-dimethylphe-
nanthrene-1-carboxylate (5a). Light yellow solid,
1
yield 69.4%, mp 172–174°C. H NMR spectrum, δ,
ppm: 7.94 s (1H), 7.84 d (J = 2.0 Hz, 1H), 7.75 d (J =
8.4 Hz, 2H), 7.38 d (J = 8.2 Hz, 2H), 7.28 d (J =
8.0 Hz, 1H), 7.21 d.d (J = 8.0 Hz, 2.0 Hz, 1H), 3.64 s
(3H), 2.87 septet (J = 6.8 Hz, 1H), 2.72 d.d (J = 17.4,
4.0 Hz, 1H), 2.43 s (3H), 2.34–2.18 m (3H), 1.88–1.56
m (5H), 1.36 s (3H), 1.25 s (3H), 1.24 d (J = 6.9 Hz,
6H). MS, m/z: 497.2 [M+H]+. Found, %: C 67.65; H
7.28; N 5.61. C28H36N2O4S. Calculated, %: C 67.71; H
7.31; N 5.64.
1
as yellow oil. Yield 70.6%. H NMR spectrum, δ,
ppm: 7.86 d (J = 2.0 Hz, 1H), 7.39 d.d (J = 8.1, 2.1 Hz,
1H), 7.28 d (J = 8.1 Hz, 1H), 3.64 s (3H), 2.90 septet
(J = 7.0 Hz, 1H), 2.75 m (2H), 2.41–2.26 m (2H), 1.83–
1.59 m (5H), 1.35 s (3H), 1.26 s (3H), 1.25 d (J = 7.0
Hz, 6H). MS, m/z: 328.2 [M]+. Found, %: C 76.72; H
8.64. C21H28O3. Calculated, %: C 76.79; H 8.59.
(1R,4aS)-Methyl 9-(p-methoxybenzenesulfonyl-
hydrazono)-1,2,3,4,4a,9,10,10a-octahydro-7-iso-
propyl-1,4a-dimethylphenanthrene-1-carboxylate
1
(5b). White solid, yield 65.8%, mp 178–180°C. H
NMR spectrum, δ, ppm: 7.90 s (1H), 7.83 d (J =
2.0 Hz, 1H), 7.70 d (J = 8.4 Hz, 2H), 7.29 d (J =
8.0 Hz, 1H), 7.21 d.d (J = 8.0 Hz, 2.0 Hz, 1H), 7.05 d
(J = 8.2 Hz, 2H), 3.79 s (3H), 3.64 s (3H), 2.87 septet
(J = 6.8 Hz, 1H), 2.79 d.d (J = 17.4, 4.0 Hz, 1H), 2.17–
2.02 m (2H), 1.91–1.43 m (6H), 1.35 s (3H), 1.26 s
(3H), 1.23 d (J = 6.9 Hz, 6H). MS, m/z: 513.2 [M+H]+.
Found, %: C 65.56; H 7.11; N 5.43. C28H36N2O5S.
Calculated, %: C 65.60; H 7.08; N 5.46.
(1R,4aS)-Methyl 9-hydrazono-1,2,3,4,4a,9,10,10a-
octahydro-7-isopropyl-1,4a-dimethylphenanthrene-
1-carboxylate (4). Compound 3 (5.22 g, 15.90 mmol)
was dissolved in EtOH (80 mL), and the mixture was
stirred upon refluxing. Then 98% hydrazine hydrate
(1.04 g, 20.67 mmol) was added to it dropwise. The
mixture was refluxed upon stirring for 1 h. After
evaporation of the solvent under reduced pressure, the
residue was recrystalized from ethanol to afford
compound 4 as a light yellow solid. Yield 87.8%, mp
(1R,4aS)-Methyl 9-(p-nitrobenzenesulfonylhyd-
razono)-1,2,3,4,4a,9,10,10a-octahydro-7-isopropyl-
1,4a-dimethylphenanthrene-1-carboxylate (5c). Light
1
152–154°C. H NMR spectrum, δ, ppm: 7.58 d (J =
1
yellow solid, yield 68.7%, mp 195–197°C. H NMR
2.0 Hz, 1H), 7.24 d.d (J = 8.0 Hz, 2.0 Hz, 1H), 7.16 d
(J = 8.0 Hz, 1H), 5.32 br s (2H), 3.64 s (3H), 2.89
septet (J = 7.0 Hz, 1H), 2.76 m (2H), 2.45–2.36 m
(2H), 1.81–1.54 m (5H), 1.34 s (3H), 1.25 s (3H), 1.24
d (J = 7.0 Hz, 6H). MS, m/z: 343.2 [M+H]+. Found, %:
C 73.62; H 8.80; N 8.16. C21H30N2O2. Calculated, %:
C 73.65; H 8.83; N 8.18.
spectrum, δ, ppm: 8.38 d (J = 8.4 Hz, 2H), 8.12 s (1H),
8.05 d (J = 8.2 Hz, 2H), 7.82 d (J = 2.0 Hz, 1H), 7.30 d
(J = 8.2 Hz, 1H), 7.22 d.d (J = 8.2 Hz, 2.0 Hz, 1H),
3.63 s (3H), 2.88 septet (J = 6.8 Hz, 1H), 2.75 d.d (J =
17.5, 4.1 Hz, 1H), 2.15–1.94 m (3H), 1.89–1.37 m
(5H), 1.35 s (3H), 1.24 s (3H), 1.20 d (J = 6.9 Hz, 6H).
MS, m/z: 528.2 [M+H]+. Found, %: C 61.43; H 6.25; N
7.94. C27H33N3O6S. Calculated, %: C 61.46; H 6.30; N
7.96.
Synthesis of benzenesulfonylhydrazone deriva-
tives of methyl dehydroabietate (5a–5f). The mixture
of compound 4 (1.50 g, 4.38 mmol) with Et3N (0.66 g,
6.52 mmol) was dissolved in dry THF (20 mL), then
solution of an appropriate phenylsulfonyl chloride
(4.51 mmol) in dry THF (15 mL) was added dropwise
upon stirring. The reaction mixture was stirred for 1 h
(1R,4aS)-Methyl 9-(p-fluorobenzenesulfonylhyd-
razono)-1,2,3,4,4a,9,10,10a-octahydro-7-isopropyl-
1,4a-dimethylphenanthrene-1-carboxylate (5d). White
solid, yield 67.3%, mp 187–189°C. 1H NMR spectrum,
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 89 No. 4 2019

822
ZHI ZHOU et al.
δ, ppm: 8.01 s (1H), 7.98 d (J = 8.4 Hz, 2H), 7.80 d
(J = 2.0 Hz, 1H), 7.40 d (J = 8.2 Hz, 2H), 7.29 d (J =
8.2 Hz, 1H), 7.21 d.d (J = 8.2 Hz, 2.0 Hz, 1H), 3.64 s
(3H), 2.86 septet (J = 6.8 Hz, 1H), 2.79 d.d (J = 17.3,
4.0 Hz, 1H), 2.39–2.24 m (2H), 2.10–1.54 m (6H),
1.35 s (3H), 1.25 s (3H), 1.22 d (J = 6.9 Hz, 6H). MS,
m/z: 501.2 [M+H]+. Found, %: C 64.71; H 6.67; N
5.57. C27H33FN2O4S. Calculated, %: C 64.78; H 6.64;
N 5.60.
1h to permit good diffusion and then incubated at 35°C
for 48 h. The inhibition zones were measured.
CONCLUSIONS
A series of benzenesulfonylhydrazone derivatives
of methyl dehydroabietate is synthesized and tested for
antibacterial activity against E. coli, S. aureus, and B.
subtilis by disk diffusion method. The experimental
results indicate that the synthesized compounds
possess pronounced antibacterial activity, among these
p-fluorobenzenesulfonylhydrazone of methyl dehyd-
roabietate demonstrates the best activity against B.
subtilis and S. aureus.
(1R,4aS)-Methyl 9-(p-trifluoromethylbenzenesul-
fonylhydrazono)-1,2,3,4,4a,9,10,10a-octahydro-7-iso-
propyl-1,4a-dimethylphenanthrene-1-carboxylate
1
(5e). White solid, yield 63.2%, mp 191–193°C. H
NMR spectrum, δ, ppm: 8.12 s (1H), 7.81 d (J =
2.0 Hz, 1H), 7.76 d (J = 8.4 Hz, 2H), 7.65 d (J = 8.2
Hz, 2H), 7.28 d (J = 8.2 Hz, 1H), 7.20 d.d (J = 8.2 Hz,
2.0 Hz, 1H), 3.63 s (3H), 2.86 septet (J = 6.8 Hz, 1H),
2.71 d.d (J = 17.4, 4.1 Hz, 1H), 2.19–2.05 m (2H),
1.83–1.56 m (6H), 1.35 s (3H), 1.26 s (3H), 1.23 d (J =
7.0 Hz, 6H). MS, m/z: 551.2 [M+H]+. Found, %: C
61.03; H 6.02; N 5.07. C28H33F3N2O4S. Calculated, %:
C 61.08; H 6.04; N 5.09.
FUNDING
The study was supported by the Qiandongnan
Science and Technology planning project [QDNco-J
word (2015) 002].
CONFLICT OF INTEREST
No conflict of interest was declared by the authors.
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(1R,4aS)-Methyl 9-(p-bromobenzenesulfonylhyd-
razono)-1,2,3,4,4a,9,10,10a-octahydro-7-isopropyl-
1,4a-dimethylphenanthrene-1-carboxylate (5f). White
solid, yield 60.3%, mp 178–180°C. 1H NMR spectrum,
δ, ppm: 8.10 s (1H), 7.88 d (J = 2.0 Hz, 1H), 7.81 d
(J = 8.4 Hz, 2H), 7.69 d (J = 8.2 Hz, 2H), 7.29 d (J =
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C 57.75; H 5.92; N 4.99.
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