Synthesis and antiinflammatory activity of 3-thiabis(cyclohexanecarboxylic) acid derivatives

Full text of DOI:10.1023/A:1010498625910

Pharmaceutical Chemistry Journal
Vol. 35, No. 1, 2001
SYNTHESIS AND ANTIINFLAMMATORY ACTIVITY
OF 3-THIABIS(CYCLOHEXANECARBOXYLIC) ACID DERIVATIVES
V. P. Krivonogov,1 G. A. Tolstikov,2 D. N. Lazareva,2 V. A. Davydova,1 F. S. Zarudii,1
I. I. Krivonogova,1 and Yu. I. Murinov1
Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 35, No. 1, pp. 25 – 28, January, 2001.
Original article submitted December 14, 1999.
R
R
The class of antiinflammatory drugs includes a group of
sulfur-containing organic compounds such as metiazinic
acid, tinoridine (kenfamin), tiaramide (solantol), etc. How-
ever, all these drugs give rise to side effects, including gas-
trointestinal tract disorders. A pronounced antiinflammatory
activity was reported for patented cyclic hydroxysulfones
[1], the most active of which was 3-hydroxytetrahydrothio-
phene-1,1-dioxide (3-hydroxysulfolan).
R
CN
COOH
CH CN
SCl2
KOH
+
140 °C
CH2
II
–40 °C
Ià, Ib
IIIà, IIIb
IVà, IVb
R
R
HOOC
S
COOH
The results of investigations carried out in the Labora-
tory of New Drugs at the Institute of Organic Chemistry
(Ufa) showed that most of the synthetic sulfones possess a
more or less pronounced antiinflammatory activity. The
maximum activity was observed for dihydroxysulfolan, pro-
ducing, in contrast to most of the known antiinflammatory
sulfur-containing compounds, no ulcerogenic action.
The purpose of this work was to synthesize and charac-
terize a series of new 3-thiabis(cyclohexanecarboxylic) acid
derivatives.
R'H
Cl Cl
Và, Vb
R
R
XOOC
S
COOX
R' R'
VIà –VId
I – V: R = Me (a), H (b);
VI: R = Me (a – c), H (d); R1 = C4H8NO (a, b, d), C5H10N (c);
The condensation of piperylene (Ia) with acrylic acid
nitrile (II) was conducted by the method described in [2 – 4]
to obtain 2-methyl-1,2,5,6-tetrahydrobenzonitrile (IIIa) with
a yield of 90%. As was previously established by
A. A. Petrov and A. F. Sapozhnikova for an initial mixture
containing cis and trans forms of piperylene in a 50 : 50 ra-
tio, the condensation with acrylonitrile at 130 – 135°C in-
volves only the trans form, whereas the cis form does not en-
ter the reaction at this temperature. However, a complete
condensation takes place at 180°C, when the cis to trans con-
version obviously takes place. We conducted the condensa-
tion process with a cis– trans mixture for 12 h at 140°C; the
unreacted cis-piperylene was distilled off.
X = H (a), Na (b – d).
The saponification of 2-methyl-1,2,5,6-tetrahydrobenzo-
nitrile (IIIa) with a 10% KOH solution, conducted for 2 h at
180°C in an autoclave and followed by acidification with
concentrated sulfuric acid, led to the formation of
tetrahydrotoluic acid (IVa) with an 88% yield. The treatment
of acid IVa and 1,2,5,6-tetrahydrobenzoic acid (IVb) with
sulfur dichloride was carried out at –40°C [5] in a methylene
chloride medium. These reactions led to 3-thiabis(2-methyl-
4-chlorocyclohexanecarboxylic) acid (Va) and 3-thiabis-
(4-chlorocyclohexanecarboxylic) acid (Vb). The reaction of
SCl2 with tetrahydrotoluic acid may lead to the formation of
solid and liquid isomers. Based on the available data, it is dif-
ficult to assign the structures. However, judging by the fact
that absorption bands in the region characteristic of the C–Cl
bond vibrations are confined within a 710 – 770 cm – 1 fre-
The synthesis was conducted according to the following
scheme.
1
Institute of Organic Chemistry, Ufa Scientific Center, Russian Academy
of Sciences, Ufa, Bashkortostan, Russia.
Bashkir State Medical University, Ufa, Bashkortostan, Russia.
2
26
0091-150X/00/3501-0026$25.00 © 2001 Plenum Publishing Corporation

Synthesis and Antiinflammatory Activity of 3-Thiabis(cyclohexanecarboxylic) Acid Derivatives
27
quency interval, the synthesized compounds occur in the
1-ee, 2-ee molecular configuration.
3-Thiabis(2-methyl-4-chlorocyclohexanecarboxylic)
acid (Va). To a mixture of 280 g (2 mole) acid IVa and
300 ml CH2Cl2 in a flask cooled down to – 40°C were added
dropwise so as to maintain this temperature 103 g (1 mole)
of SCl2. The reaction mixture was stirred at this temperature
for 30 min and allowed to heat up to room temperature, after
which the stirring was continued for 2 h. Then CH2Cl2 was
distilled off at a reduced pressure (water-jet pump) and a wa-
ter bath temperature not exceeding 40°C to obtain 380 g
(100%) of crystalline acid Va; m.p., 65 – 70°C. The rough
product was recrystallized from an ethyl ether – petroleum
ether mixture (40 – 70°C) to obtain diacid Va; yield, 80%;
m.p., 70 – 71°C; C16H24Cl2O4S (mol. weight, 383.33); IR
spectrum (n, C–S): 625 – 670 (C–S), 710 – 770 (CCl),
1710 – 1740 (COCH), 1080 – 1180.
The subsequent reactions of acids Va and Vb with
morpholine or piperidine were carried out according to a pro-
cedure described in [6]. These interactions led to
3-thiabis(2-methyl-4-morpholinocyclohexanecarboxylic)
acid (VIa) with a 90% yield. Additional treatment of the re-
action mixture with water and alkali gave a disodium salt
VIb of this acid with a yield of 80%. The other disodium
salts were obtained using analogous procedures [7].
Purity of the reaction products was checked and the pro-
posed structures of compounds were confirmed by data of
the IR absorption spectroscopy and elemental analyses. The
IR spectra of compound VI exhibit absorption bands in the
regions of 625 – 670 and 710 – 770 cm – 1 assigned to
stretching vibrations of the C–S bonds and tertiary nitrogen
atoms, respectively. The IR spectra of compounds V and VI
contain additional bands at 1710 – 1740 cm – 1 belonging to
CO groups.
3-Thiabis(2-methyl-4-morpholinocyclohexanecarbo-
xylic) acid (VIa). To 115 g (0.3 mole) of acid Va in a flask
was gradually (over 1 h) added 261 g (3 mole) of
morpholine. The reaction mixture was heated to 135°C,
stirred at this temperature for 6 – 8 h, and allowed to stand
cooling overnight. The precipitated crystals of
C4H10NO × HCl were filtered and washed with toluene.
Finally, excess morpholine and toluene were distilled off to
leave 130 g (90%) of acid VIa. The rough product was puri-
fied by washing with water and extracting with toluene. Acid
VIa: C24H40N2O6S (mol. weight, 484.65); IR spectrum (n,
C–S): 1710 – 1740 (C–O), 1070 – 1170 (C–O), 625 – 670
(C–S).
EXPERIMENTAL CHEMICAL PART
The IR spectra were measured on
a
UR-20
spectrophotometer (Carl Zeiss – Jena, Germany) equipped
with NaCl and LiF prisms. The samples were prepared as
thin liquid films of nujol mulls. The melting temperatures
were determined with the aid of a Boetius heating table. The
data of elemental analyses (C, H, Cl, N, S) agree with the re-
sults of analytical calculations according to the empirical for-
mulas.
3-Thiabis(2-methyl-4-morpholinocyclohexanecarbo-
xylic) acid disodium salt (VIb). To 115 g (0.3 mole) of acid
Va in a flask was gradually (over 1 h) added 261 g (3 mole)
of morpholine. The reaction mixture was heated to 135°C,
stirred at this temperature for 6 – 8 h, and allowed to stand
cooling overnight. On the next day, 400 ml of water was
added and the solution was saturated with solid NaOH until
separation into two layers. The organic layer was separated
and the excess morpholine was distilled off on a rotor evapo-
rator. The residue was subjected to azeotrope drying with
benzene and washed with ether to obtain 126 g (80%) of a
crystalline disodium salt VIb. The residual NaOH was re-
moved by repeated washing with water (50 ml), followed by
azeotrope drying with benzene. Disodium salt VIb: m.p.,
200 – 202°C; C24H38Na2N2O6S; IR spectrum (n, C–S): 1580,
1410 (RCOO–), 1070 – 1120 (C–O–C).
Tetrahydrotoluic acid (IVa). A 2000-ml autoclave ves-
sel was sequentially charged in an argon atmosphere with
369 g (5.45 mole) of piperylene (Ia) preliminarily dried over
CuCl2 and distilled over CaH2, 177 g (3.3 mole) of
acrylonitrile (II) distilled at atmospheric pressure, and 2 g of
hydroquinone. Then the autoclave was closed and heated to
140°C. The reaction mixture was stirred at this temperature
for 12 h, cooled, and discharged (530 g). The light fractions
were distilled off at atmospheric pressure (b.p., 40 – 60°C) to
obtain 100 g of cis-piperylene (nD20, 1.4339). The residue was
distilled in vacuum to obtain 352 g (90%) of 2-methyl-
1,2,5,6-tetrahydrobenzonitrile (IIIa); b.p., 72 – 75°C/5 Torr;
nD20, 1.4708.
The autoclave vessel was sequentially charged with
100 g (0.63 mole) of nitrile and 1100 ml of a 10% KOH solu-
tion. Then the autoclave was closed, heated to 180°C, kept at
this temperature for 2 h, and cooled. The reaction mixture
was discharged into a flask, acidified with concentrated sul-
furic acid (until obtaining an acid test response), and ex-
tracted with benzene. Finally, the solvent was distilled off
and the residue was distilled in vacuum to obtain 102.3 g
(88%) of 2-methyl-1,2,5,6-tetrahydrobenzoic acid (IVa);
b.p., 162°C/1 Torr; nD20, 1.4722. On standing, acid IVa ex-
3-Thiabis(2-methyl-4-piperidinocyclohexanecarboxy-
lic) acid disodium salt (VIc). To 115 g (0.3 mole) of acid Va
in a flask was gradually (over 1 h) added 255 g (3 mole) of
piperidine. The reaction mixture was gradually heated to
120°C, stirred at this temperature for 6 – 8 h, and allowed to
stand cooling overnight. On the next day, 400 ml of water
were added to dissolve the precipitated crystals and the re-
sulting homogeneous solution was saturated with solid
NaOH until separation into two layers. The upper organic
layer was separated and the excess piperidine was distilled
off on a rotor evaporator. The residue was subjected to
hibits crystallization.

28
V. P. Krivonogov et al.
the stirring was continued for 2 h. Then methylene chloride
was distilled off at a reduced pressure (water-jet pump) and a
water bath temperature not exceeding 40°C to obtain 512 g
(96%) of acid Vb in the form of a highly viscous ropy liquid
(mol.weight, 355.28).
TABLE 1. Acute Toxicity of Compounds
VIa – VId upon Single Intraperitoneal Injection in
Mice
Compound
LD50, mg/kg
VIa
VIb
VIc
VId
1350
4800
1200
1750
250
3-Thiabis(4-morpholinocyclohexanecarboxylic) acid
disodium salt (VId). Compound VId was obtained from
diacid Vb using a procedure analogous to that described
above for disodium salt VIb. Disodium salt VId: yield, 80%;
m.p., 160°C (with sublim.); C22H34Na2N2O6S; IR spectrum
(n, cm – 1): 1580, 1410 (COO–).
Phenylbutazone
Acetysalicylic acid
Brufen
3000
370
Indomethacin
30
EXPERIMENTAL PHARMACOLOGICAL PART
Experimental Methods
The experiments were performed on 320 white male and
female mongrel mice weighing 18 – 20 g obtained from the
Rappolovo nursery (Russian Academy of Medical Sciences).
The acute toxicity was studied on a group of 160 mice, to
which the synthesized compounds were introduced by single
intraperitoneal injections in a dose range from 50 to
1600 mg/kg. The LD50 values were determined by a conven-
tional method on the 10th day after drug injection [8].
The antiinflammatory activity was studied on mice and
rats with inflammation models induced by 1% carrageenan
or 3% formalin solutions injected under one foot aponeurosis
in each animal of the test group. The thermal burn model was
induced by a conventional method [9], whereby a mice paw
below the knee is exposed for 30 sec in hot (55°C) water.
The inflammation process development and the
antiinflammatory activity in rats were determined by the
oncometric techniques 1, 2, 3, 6, and 24 h after the inflam-
mation model induction. The inflammation process in test
mice divided into three groups was monitored by cutting
paws and determining percentage weight gain for the dam-
aged feet relative to intact ones. The experimental data pre-
sented in Tables 2 and 3 refer to the volume or weight gain
determined 3 h after the inflammation model induction (this
time corresponds to the maximum degree of edema develop-
ment). The synthesized compounds were introduced into the
test animals (1 h before and 3 and 6 h after the inflammation
azeotrope drying with benzene and washed with ether to ob-
tain 95 g (60%) of disodium salt VIc – a crystalline yellow
powder melting at 105 – 108°C. For the analysis, the product
was purified by additional washing with water, followed by
azeotrope drying with benzene. Disodium salt VIc: m.p.,
108 – 110°C; C26H42Na2N2O4S; IR spectrum (n, C–S): 1570,
1410 (RCOO–).
3-Thiabis(4-chlorocyclohexanecarboxylic) acid (Vb).
To a mixture of 378 g (3 mole) 1,2,5,6-tetrahydrobenzoic
acid (IVb) and 40 ml CH2Cl2 in a flask cooled down to
–(20 – 40)°C was added dropwise so as to hold the tempera-
ture in this interval 154 g (1.5 mole) of sulfur dichloride in
200 ml of methylene chloride. Upon completely adding the
SCl2, the reaction mixture was stirred at this temperature for
1 h and allowed to heat up to room temperature, after which
TABLE 2. Antiinflammatory Activity of Compounds VIa – VId
with Respect to Formalin and Carrageenan Edema Models in Rats
Formalin edema1
Carrageenan edema2
Foot edema
Com-
pound
Foot edema
volume
Dose,
Dose,
volume
mg/kg gain, %
of initial
P
P
mg/kg gain, %
of initial
VIa
135
67
< 0.002
< 0.001
< 0.002
< 0.001
< 0.001
< 0.001
< 0.02
< 0.01
< 0.05
–
135
480
120
175
< 0.01
< 0.01
< 0.02
< 0.001
< 0.001
40.0 ± 3.0
43.6 ± 1.0
39.6 ± 3.6
40.0 ± 2.1
39.3 ± 2.6
46.4 ± 2.6
47.3 ± 2.9
45.0 ± 2.6
46.8 ± 4.3
60.4 ± 3.5
54.5 ± 5.4
55.8 ± 2.7
47.3 ± 4.2
40.6 ± 2.7
VIb
VIc
VId
480
240
120
60
TABLE 3. Antiinflammatory Activity of Compounds VIa – VId
with Respect to Thermal Burn Models in Mice
Foot weight gain,
Compound
Dose, mg/kg
P
% of intact
175
87
VIa
VIb
VIc
VId
135.0
480.0
120.0
175.0
80.0
–
> 0.25
< 0.05
> 0.1
74.7 ± 6.3
68.9 ± 3.3
70.8 ± 3.9
60.0 ± 4.2
64.4 ± 4.4
83.3 ± 3.9
Brufen
80
80
–
47.3 ± 3.5
79.8 ± 6.0
Control
–
< 0.05
Notes: 1,2 Each compound was studied (in certain doses) on test
groups containing seven (for formalin model) and six (carrageenan
model) animals.
Brufen
Control
–

Synthesis and Antiinflammatory Activity of 3-Thiabis(cyclohexanecarboxylic) Acid Derivatives
29
2. G. A. Tolstikov, V. V. Fryazinov, V. P. Krivonogov, et al., USSR
Inventor’s Certificate No. 852,856; Byull. Izobret., No. 29
(1981).
model induction) via intragastric tube in a dose of 1/10 or
1/20 LD50.
Results and Discussion
3. A. S. Onishchenko, Diene Synthesis [in Russian], Izd. AN
SSSR, Moscow (1963).
It was established that, according to the standard classifi-
cation scheme [10 – 12], all the synthesized compounds be-
long to the group of low-toxicity substances (Table 1).
It was found that all compounds decrease the extent of
the carrageenan-induced inflammatory edema, the drug ef-
fect in the 1/10 LD50 dose being comparable with that of the
reference drug brufen taken in a dose of 1/5 LD50 (Table 2).
Similar results were observed for the formalin induced in-
flammation model, where a positive effect (edema volume
decrease) was produced by the drugs administered in a dose
of both 1/10 and 1/20 LD50.
Compounds VIb and VId (but not VIa and VIc) produced
an antiinflammatory action with respect to the thermal burn
model as well (Table 3). Thus, the synthesized compounds
possess antiinflammatory properties comparable with those
of brufen, but their therapeutic breadth exceeds that of the
reference drug.
4. B. A. Arbuzov and B. G. Kataev, Zh. Obshch. Khim., 20, 63
(1950).
5. G. A. Tolstikov, N. N. Novitskaya, N. S. Zefirov, et al., Tetrahe-
dron, No. 17, 2655 – 2661 (1978).
6. V. P. Krivonogov, R. M. Shayakhetova, V. I. Dronov, et al., Zh.
Prikl. Khim., No. 11, 2505 – 1510 (1981).
7. V. P. Krivonogov. G. A. Tolstikov, D. N. Lazareva, et al., USSR
Inventor’s Certificate No. 1,193,996; Byull. Izobret., No. 33
(1985).
8. M. L. Belen’kii, Elements of the Quantitative Assessment of the
Pharmacological Effect [in Russian], Medgiz, Leningrad
(1963).
9. M. M. Golikov, Antibiotiki, No. 6, 50 – 51 (1958).
10. I. F. Izmerov, I. V. Sanotskii, and K. K. Sidorov, Toxicological
Parameters of Industrial Poisons upon Single Administration
[in Russian], Meditsina, Moscow (1977).
11. O. N. Elizarova, Determination of Threshold Doses of Indus-
trial Poisons for Peroral Administration [in Russian],
Meditsina, Moscow (1971), pp. 44 – 55.
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