Synthesis and pharmacology of new dithiocarbamic acid esters derived from phenothiazine and diphenylamine

Article abstract of DOI:10.1002/(SICI)1521-4184(199912)332:12<422::AID-ARDP422>3.0.CO;2-0

2-Methylthio-10-[N,N-disubstituted-thiocarbamoylthio)acetyl]- phenothiazines (4a-g) and N-(3-methylthiophenyl)-N-[(N,N-disubstituted- thiocarbamoylthio)acetyl]phenylamines (5a-g) were synthesized by subsequent treatment of 2-methylthio-10-chloroacetylphenothiazines (1) and N-(3- methylthiophenyl)-N-chloroacetylphenylamine (2) with potassium salts of N,N- disubstituted dithiocarbamic acid derivatives (3a-i). The structures of the compounds were determined by analytical and spectral (IR, ¹H NMR, ¹³C NMR, EIMS) methods. The antihistaminic and anticholinergic activities of 4a, 4c, 4e-g, 5a-c 5e, and 5g were evaluated in comparison with H₁-receptor antagonist mepyramine and nonselective cholinergic antagonist atropine. In the first series of experiments, the cumulative concentration-response curves to histamine (10^-8-10^-4 M) and acetylcholine (10^-8-10^-4 M) were constructed in separate fundus strips. The test compounds exhibited marked antihistaminic activity at 10^-6 M concentration but compounds did not influence acetylcholine induced contractions. Concentration-related experiments carried out on 4g and 5g revealed that a moderate antihistaminic activity was present at 10^-7 M concentration of the compounds and became strong at higher concentrations. In the second series of experiments, the cumulative concentration-response curve to histamine (10^-9-10^-4 M) was constructed in guinea-pig ileum segments. Maximal responses were obtained by 10^-6-3 x 10^-6 M concentrations of histamine in ileum segments. Similar inhibitions of histamine contractions were also obtained with the test compounds. Their inhibitory effectiveness was evaluated by comparing the pA₂ values.

Full text of DOI:10.1002/(SICI)1521-4184(199912)332:12<422::AID-ARDP422>3.0.CO;2-0

422
Karali and co-workers
Synthesis and Pharmacology of New Dithiocarbamic Acid Esters
Derived from Phenothiazine and Diphenylamine
a)
a)
a)
a)
b)
b)
Nilgün Karal1 *, Idil Apak , Sumru Özk1r1ml1 , Aysel Gürsoy , Sönmez Uydes Dogan , Aylin Eraslan , and
b)
Osman Özdemir
a) Department of Pharmaceutical Chemistry, b) Department of Pharmacology, Faculty of Pharmacy, University of Istanbul, 34452 Istanbul, Turkey
Key Words: Dithiocarbamic acid esters; phenothiazines; diphenylamines; antihistaminic activity; anticholinergic activity
dopamine levels and may have therapeutic value in some
diseases resulting from dopamine-acetylcholine imbalance.
Beginning in the mid-1940’s, several antihistaminic drugs
have been discovered as a result of bridging the aryl units of
agents related to the ethylenediamines. The diaryl substitu-
tion pattern is present in both the first and second generation
Summary
2-Methylthio-10-[(N,N-disubstituted-thiocarbamoylthio)acetyl]-
phenothiazines (4a–g) and N-(3-methylthiophenyl)-N-[(N,N-
disubstituted-thiocarbamoylthio)acetyl]phenylamines (5a–g)
were synthesized by subsequent treatment of 2-methylthio- 10-
chloroacetylphenothiazines (1) and N-(3-methylthiophenyl)-N-
chloroacetylphenylamine (2) with potassium salts of
N,N-disubstituted dithiocarbamic acid derivatives (3a–i). The
structures of the compounds were determined by analytical and
spectral (IR, 1H NMR, 13C NMR, EIMS) methods. The antihist-
aminic and anticholinergic activities of 4a, 4c, 4e–g, 5a–c, 5e, and
5g were evaluated in comparison with H1-receptor antagonist
mepyramine and nonselective cholinergic antagonist atropine.
In the first series of experiments, the cumulative concentration-re-
sponse curves to histamine (10–8–10–4 M) and acetylcholine
(10–8–10–4 M) were constructed in seperate fundus strips. The test
antihistamines and is essential for significant H -receptor
1
affinity. Furthermore, several SAR studies suggest that the
two aryl moieties must be capable of adopting a noncoplanar
conformation relative to each other for optimal interaction
with the H -receptor. The two aromatic systems may be
1
linked as in the tricyclic antihistamines. Most H -antagonists
1
contain substituents in one of the aryl rings and these influ-
[1]
ence antihistamine potency, as well as biodisposition
.
In line with this reasoning, we synthesized 2-methylthio-
10-[(N,N-disubstituted thiocarbamoylthio)acetyl]pheno-
thiazines and N-(3-methylthiophenyl)-N-[(N,N-disubsti-
tuted thiocarbamoylthio)acetyl]phenylamines and tested
them for antihistaminic and anticholinergic activities.
compounds exhibited marked antihistaminic activity at 10–6
M
concentration but compounds did not influence acetylcholine in-
duced contractions. Concentration-related experiments carried out
on 4g and 5g revealed that a moderate antihistaminic activity was
present at 10–7 M concentration of the compounds and became
strong at higher concentrations. In the second series of experi-
ments, the cumulative concentration-response curve to histamine
(10–9–10–4 M) was constructed in guinea-pig ileum segments.
Maximal responses were obtained by 10–6–3×10–6 M concentra-
tions of histamine in ileum segments. Similar inhibitions of hista-
mine contractions were also obtained with the test compounds.
Their inhibitory effectiveness was evaluated by comparing the pA2
values.
Results and Discussion
Reaction of 2-methylthio-10-chloroacetylphenothiazine
(1) and N-(3-methylthiophenyl)-N-chloroacetylphenylamine
(2) with corresponding N,N-disubstituted potassium dithio-
carbamates (3a–i) in ethanolic medium furnished 2-methyl-
thio-10-[(N,N-disubstituted thiocarbamoylthio)acetyl]-
phenothiazines (4a–g) and N-(3-methylthiophenyl)-N-[(N,N-
disubstituted thiocarbamoylthio)acetyl]phenylamines (5a–g)
(Scheme, Table 1). The structures of 4a–g and 5a–g were
1
13
confirmed by physical and spectral (IR, H NMR, C NMR,
EIMS) data.
Introduction
The phenothiazine and the diphenylamine classes of drugs
IR spectra of 4 and 5 showed two bands resulting from
were among the first useful antihistaminic agents. Pro- amide C=O and thiocarbamoyl group C=S stretchings in the
–1
[6,7]
methazine, trimeprazin, mepyramine, and tripelenamine are
1689–1668 and 1248–1224 cm regions, respectively
.
1
highly effective histamine H -receptor antagonists. In addi-
In the H NMR spectra of 4 and 5 the SCH and SCH protons
1
3
2
tion to antihistaminic activity, these compounds have an- were observed as singlets at 2.36–2.71 and 3.95–4.61 ppm,
[8,9]
ticholinergic, antiemetic and sedative activities. Some
phenothiazines have limited utility in Parkinson-like syn-
respectively
. Other protons resonated in the expected
13
regions. In the C NMR spectra of 4 and 5 the SCH , SCH ,
3
2
dromes as a result of their ability to block central muscarinic C=O, and C=S peaks which verified the proposed dithiocar-
[1]
receptors
.
bamic acid ester structure appeared singlets at 14.46–14.84,
On the other hand, considerable interest has been focused
on the dithiocarbamates which have been shown to possess a
broad spectrum of biological activities such as anticholiner-
39.77–41.34, 165.61–166.73, 189.56–194.84 ppm regions,
[10]
respectively
. Peaks were assigned by DEPT 135 experi-
ments. EIMS of 4a, 4g, 5b, and 5g chosen as prototypes
[2]
[3]
[4]
+
gic , fungicidal , and antibacterial effects . The enzyme showed molecular ions (M ) with low intensities. The major
dopamine β-hydroxylase is inhibited by compoundschelating fragmentation pathway involved the cleavage of the CO-A
its copper, such as disulfiram, and its metabolite, (CO-N) or the CS-S bonds of the dithiocarbamate moiety
[5]
[11,12]
diethyldithiocarbamic acid . This increases central which was in accordance with the literature
.
Arch. Pharm. Pharm. Med. Chem.
© WILEY-VCH Verlag GmbH, D-69451 Weinheim, 1999
0365-6233/99/1212/0422 $17.50 +.50/0

New Dithiocarbamic Acid Esters
423
Table 1. Physical constants of 4a–g and 5a–g.
——————————————————————————————
Comp.
Yield
(%)
Mp
°C
Formula a)
(MW)
——————————————————————————————
4a
4b
4c
4d
4e
4f
85
64
70
77
56
79
85
87
99
90
99
79
72
80
162–165
78–80
130–134
132
C20H20N2OS4.H2O
(450.66)
C22H24N2OS4
(460.69)
C22H24N2OS4
(460.69)
C28H28N2OS4
(536.78)
156–159
75
C26H25N3OS4
(523.74)
C27H27N3OS4
(537.77)
4g
5a
5b
5c
5d
5e
5f
181–186
99
C20H20N2O2S4.11/2H2O
(475.66)
C20H24N2OS3
(404.60)
128–133
128–130
112
C20H22N2OS3
(402.59)
C21H24N2OS3
(416.61)
C22H26N2OS3
(430.64)
158–160
124–128
99
C22H26N2OS3.H2O
(448.66)
C28H30N2OS3.1/2H2O
(515.73)
5g
C20H22N2O2S3
(418.59)
——————————————————————————————
a) Elemental analyses were within ± 0.4% of calculated values.
Table 2. The inhibitory effects of some 4 and 5 on histamine- and acetyl-
choline-induced contractions in rat gastric fundus strips.
——————————————————————————————
Compound *
% Inhibition
Histamine (10–4 M) Acetylcholine (10–4 M)
——————————————————————————————
4a
4c
4e
4f
79.56 ± 10.52
79.46 ± 10.54
78.78 ± 2.95
87.78 ± 6.22
91.57 ± 5.67
0
0
0
0
4g
3.0 ± 3.0
Scheme
5a
5b
5c
5e
5g
87.67 ± 9.29
79.77 ± 4.93
92.36 ± 4.51
87.39 ± 1.50
96.87 ± 2.73
0
0
0
0
The experiments were performed to evaluate the antihista-
minic and anticholinergic activities of 4a, 4c, 4e–g, 5a–c, 5e
and 5g in comparison with H -receptor antagonist mepyr-
5.98 ± 2.4
1
Atropine
amine and nonselective cholinergic antagonist atropine in rat
10–4 M
–
100
[13]
gastric fundus strips
. Some experiments were also per-
formed in guinea-pig ileum, which is known to be more
sensitive to histamine, in order to clarify the antihistaminic
potencies of the compounds. For this purpose, in the first
series of experiments, the cumulative concentration-response
Mepyramine
10–6 M
100
100
–
–
10–4 M
——————————————————————————————
* Rat fundus strips were incubated with 10–6 M concentration of the com-
pounds in the antihistaminic activity experiments whereas with 10–4 M of
the compounds in the anticholinergic activity experiments for 15 min.
n = 3–6 in each group.
–8
–4
–8
curves to histamine (10 –10 M) and acetylcholine (10 –
–4
10 M) were constructed in separate fundus strips. Maximal
–4
responses were obtained at 10 M for both histamine and
Arch. Pharm. Pharm. Med. Chem. 332, 422–426 (1999)

424
Karali and co-workers
Figure. Effects of some 4 (Fig. a), 5 (Fig. b) and mepyramine at 10–6 M concentration on the contractions induced by histamine in guinea-pig ileum (n = 4–6)
acetylcholine. As can be seen in Table 2 the test compounds ileum segments. Histamine was found more potent in guinea
did not influence acetylcholine induced contractions andhave pig ileum than rat fundus strips (EC values; in ileum:
50
–4
no significant anticholinergic activity even at 10 M concen- 6.92±0.12 vs in fundus strips: 5.47 × 0.17, n = 6, p < 0.05).
–6
–6
tration.
Maximal responses were obtained by 10 –3±10 M con-
centrations of histamine in ileum segments. Similar inhibi-
tions on histamine contractions were also obtained with the
test compounds in guinea pig ileum. A shift to right was
The EC value of acetylcholine also did not change in the
presence of either of these compouds (EC values; +4a: 5.62
± 0.32; +4c: 5.38 ± 0.28; +4e: 5.71 ± 0.31; +4f: 5.55 ± 0.27;
+4g: 5.80 ± 0.35; +5a: 5.45 ± 0.37; +5b: 5.65 ± 0.37; +5c:
50
50
observed in the concentration-response curve of histamine in
–6
5.47 ± 0.32; +5e: 5.35 ± 0.28; +5g: 5.87 ± 0.23 vs control: the presence of the compounds at 10 M , especially with
5.58 ± 0.35, p > 0.05, n = 4–6). On the other hand, compounds derivatives of 5 (Figure).
–6
Their inhibitory effectiveness was evaluated by comparing
exhibited marked antihistaminic activity at 10 M concen-
tration. Concentration-related experiments carried out on 4g
and 5g revealed that a moderate antihistaminic activity was
the pA values (Table 4). In the main, the antihistaminic
2
potencies of the compounds were found similar among the
derivatives of 4 or 5. However, a difference was observed in
the inhibitory effectiveness between 4 and 5. In general,
diphenylamine derivatives 5 were more active than phe-
nothiazine derivatives4 where the most active compound was
R-morpholine substituted derivative 5g. On the other hand,
–7
present at 10 M concentration of the compounds and be-
came strong at their higher concentrations (Table 3).
Whereas, lower concentrations of the compounds did not
show a significant inhibitory effect on histamine-induced
contractions in rat gastric fundus strips. In the second series
of experiments, the cumulative concentration-response curve
pA values of all compounds were found lower than me-
2
–9
–4
pyramine which indicates that new compounds were less
effective than mepyramine (Table 4).
to histamine (10 –10 M) were constructed in guinea-pig
Table 3. Concentration-related inhibitory effects of 4g and 5g on histamine-
induced contraction in rat gastric fundus strips.
Table 4. pA2 values of the compouds and mepyramine in guinea-pig ileum.
——————————————————————————————
——————————————————————————————
Compound *
Conc.
% Inhibition of histamine (10–4 M)
induced contraction
Compound *
pA2 values (–log M)
——————————————————————————————
——————————————————————————————
4g
10–9 M
10–8 M
0
4a
4c
4e
4f
6.44
6.62
6.35
7.41
6.20
1.20 ± 1.2
17.29 ± 5.46
91.57 ± 5.67
10–7
M
10–6 M
10–5 M
10–4 M
4g
100
100
5a
5b
5c
5e
5g
6.90
7.31
7.59
7.91
7.95
5g
10–9
M
0
0
10–8 M
10–7 M
31.25 ± 7.67
87.52 ± 6.35
96.87 ± 2.73
10–6
M
10–5 M
Mepyramine
9.30
10–4 M
100
——————————————————————————————
* Concentration-response curve of histamine was repeated in the presence
of increasing concentrations (10–8–10–5 M) of the compounds or
mepyramine (n = 4–6).
——————————————————————————————
* Rat fundus strips were incubated with those concentrations of the com-
pounds for 15 min prior to administration of histamine, n = 4–6.
Arch. Pharm. Pharm. Med. Chem. 332, 422–426 (1999)

New Dithiocarbamic Acid Esters
425
1)
C-5a), 133.81 (phenot. C-2), 137.73 (phenot. C-9a), 138.48 (phenot. C-10a),
165.76 (C=O), 192.57 (C=S).
Experimental Part
Chemistry
2-Methylthio-10-[(4-phenyl-1-piperazinylthiocarbamoylthio)acetyl]-
phenothiazine (4e)
Melting points were estimated with a Büchi 530 apparatus in open capil-
laries and are uncorrected. Elemental analyses were performed on a Carlo
Erba 1106 elemental analyzer. IR spectra were recorded on KBr discs, using
IR: ν = 1687 cm–1 (C=O), 1238 (C=S).– 1H NMR: δ = 2.37 (s, 3H, SCH3),
3.11 (t, 4H, pipz. 3-H, 5-H), 4.20, 4.31 (2 br.s, 2H each, pipz. 2-H, 6-H), 4.31
(s, 2H, SCH2), 7.05–7.54 (m, 12H, arom.).– 13C-NMR proton decoupled-
DEPT 135: δ = 14.84 (SCH3), 40.11 (SCH2), 47.42 (pipz. C-2, C-3, C-5,
C-6), 115.34 (phenyl C-2, C-6), 119.15 (phenyl C-4), 124.32 (phenot. C-1),
124.73 (phenot. C-9), 125.34 (phenot. C-3), 127.04 (phenot. C-7), 127.30
(phenot. C-8), 127.74 (phenot. C-6), 127.96 (phenot. C-4), 128.36 (phenot.
C-4a), 128.90 (phenyl C-3, C-5), 129.67 (phenot. C-5a), 133.65 (phenot.
C-2), 137.71 (phenot. C-9a), 138.17 (phenyl C-1), 138.43 (phenot. C-10a),
165.64 (C=O), 193.95 (C=S).
1
a Perkin-Elmer 1600 spectrometer. H NMR and 13C NMR proton decou-
pled-DEPT 135 spectra were taken on Bruker ARX 300 (1H: 300 MHz, 13C:
75.5 MHz, [d6]DMSO) spectrophotometer. EIMS were determined on aVG
Zab Spec (70 eV) mass spectrometer.
Synthesis of 2-methylthio-10-chloroacetylphenothiazine (1) and
N-(3-methylthiophenyl)-N-chloroacetylphenylamine (2)
2-Methylthiophenothiazine or N-(3-methylthiophenyl)phenylamine
(0.050 mol) and chloroacetyl chloride (0.055 mol) in 20 mL dry benzene
were refluxed for 6 h. After evaporation of the solvent under reduced
pressure, the residue was neutralised with saturated solution of sodium
bicarbonate and allowed to stand overnight. It was filtered and washed with
water and recrystallized with ethanol.
2-Methylthio-10-[(4-morpholinylthiocarbamoylthio)acetyl]phenothiazine
(4g)
IR: ν = 1668 cm–1 (C=O), 1232 (C=S).– 1H NMR: δ = 2.54 (s, 3H, SCH3),
1.37 (t, 4H, mor. 3-H, 5-H), 3.97, 4.08 (2 br.s, 2H each, mor. 2-H, 6-H), 4.46
(br.s, 2H, SCH2), 7.24–7.70 (m, 7H, arom.).– 13C-NMR proton decoupled-
DEPT 135: δ = 14.84 (SCH3), 39.96 (SCH2), 65.40 (mor. C-2, C-3, C-5, C-6),
124.31 (phenot. C-1), 124.73 (phenot. C-9), 125.32 (phenot. C-3), 127.04
(phenot. C-7), 127.30 (phenot. C-8), 127.73 (phenot. C-6), 127.95 (phenot.
C-4), 128.27 (phenot, C-4a), 129.68 (phenot. C-5a), 133.65 (phenot. C-2),
137.70 (phenot. C-9a), 138.41 (phenot. C-10a), 165.61 (C=O), 194.37
(C=S).– EIMS; m/z (%) = 448 (1) [M+], 319 (3), 245 (61), 244 (40), 205 (29),
204 (100), 130 (54), 86 (36).
Synthesis of potassium salts of N,N-disubstituted dithiocarbamic acids (3a–i)
Potassium hydroxyde (0.010 mol) was dissolved in ethanol (100 mL) with
constant stirring. After addition of the secondary amine (0.010 mol) the
mixture was cooled in an ice bath and carbon disulphide (0.100 mol) was
added dropwise with stirring. Further agitation of the reaction mixture thus
obtained for 1h at room temperature, evaporation of the solvent under
reduced pressure, and subsequent addition of dry ether until precipitation
reached completion, filtration afforded 3a–i which were either recrystallized
from ethanol or used without further purification.
N-(3-Methylthiophenyl)-N-[(1-pyrolidinylthiocarbamoylthio)acetyl]-
phenylamine (5b)
IR: ν = 1689 cm–1 (C=O), 1238 (C=S).– 1H NMR: δ = 1.99, 2.11 (2quin.,
2H each, pyr. 3-H, 4-H), 2.56 (s, 3H, SCH3), 3.71, 3.82 (2t, 2H each, pyr.
2-H, 5-H), 4.16 (s, 2H, SCH2), 7.01–7.68 (m, 9H, arom.).– 13C-NMR proton
decoupled-DEPT 135: δ = 14.46 (SCH3), 23.67, 25.56 (pyr. C-3, C-4), 40.38
(SCH2), 50.54, 55.02 (pyr. C-2, C-5), 125.78, 128.07, 128.87 (=CH), 139.72
(C=C), 166.29 (C=O), 190.14 (C=S). EIMS m/z (rel.int %): 402 (2) [M+],
289 (7), 215 (64), 189 (85), 188 (79), 114 (100), 70 (42).
Synthesis of 2-Methylthio-10-[(N,N-disubstituted thiocarbamoylthio)-
acetyl] phenothiazines (4a–g) and N-(3-Methylthiophenyl)-N-[(N,N-disub-
stituted thiocarbamoylthio)acetyl] phenylamines (5a–g)
To an ethanolic solution of 1 or 2 (0.003 mol), 3a–i (0.003 mol) was added
and the reaction mixture was heated under reflux for 1h. The products that
formed after cooling were collected by filtration, washed with water, and
recystallized from ethanol.
N-(3-Methylthiophenyl)-N-[(1-piperidinylthiocarbamoylthio)acetyl]-
phenylamine (5c)
2-Methylthio-10-[(1-pyrolidinylthiocarbamoylthio)acetyl]phenothiazine
(4a)
IR: ν = 1676 cm–1 (C=O), 1248 (C=S).– 1H NMR: δ = 1.84 (br.s, 6H, pipd.
3-H, 4-H, 5-H), 2.69 (s, 3H, SCH3), 4.12, 4.39 (2 br.s, 2H each, pipd. 2-H,
6-H), 4.29 (s, 2H, SCH2), 7.16–7.82 (m, 9H, arom.).– 13C-NMR proton
decoupled-DEPT 135: δ = 14.46 (SCH3), 23.31 (pipd. C-3, C-4, C-5), 40.85
(SCH2), 47.62, 49.84 (pipd. C-2, C-6), 125.42, 127.71, 127.92, 128.63
(=CH), 139.42 (C=C), 166.28 (C=O), 193.07 (C=S).
IR: ν = 1670 cm–1 (C=O), 1224 (C=S).– 1H NMR: δ = 2.07, 2.19 (2quin.,
2H each, pyr. 3-H, 4-H), 2.71 (s, 3H, SCH3), 3.79, 3.87 (2t, 2H each, pyr.
2-H, 5-H), 4.61 (br.s, 2H, SCH2), 7.40–7.87 (m, 7H, arom.).– 13C-NMR
proton decoupled-DEPT 135: δ = 14.83 (SCH3), 23.63, 25.51 (pyr. C-3, C-4),
39.77 (SCH2), 50.45, 55.00 (pyr. C-2, C-5), 124.28 (phenot. C-1), 124.72
(phenot. C-9), 125.28 (phenot. C-3), 127.04 (phenot. C-7), 127.28 (phenot.
C-8), 127.74 (phenot. C-6), 127.96 (phenot. C-4), 128.32 (phenot. C-4a),
129.73 (phenot. C-5a), 133.67 (phenot. C-2), 137.72 (phenot. C-9a), 138.44
(phenot. C-10a), 165.75 (C=O), 189.56 (C=S). -EIMS; m/z (%) = 432 (4)
[M+], 319 (22), 245 (49), 244 (20), 188 (100), 114 (32), 70 (5).
N-(3-Methylthiophenyl)-N-[(4-methyl-1-piperidinylthiocarbamoylthio)-
acetyl] phenylamine (5e)
IR: ν = 1675 cm–1 (C=O), 1233 (C=S).– 1H NMR: δ = 0.85 (d, 3H, CH3),
0.97–1.70 (m, 5H, pipd. 3-H, 4-H, 5-H), 2.42 (s, 3H, SCH3), 4.01 (s, 2H,
SCH2), 4.36, 5.13 (2 br.s, 2H each, pipd. 2-H, 6-H), 7.03-7.53 (m, 9H, arom.).
2-Methylthio-10-[(4-methyl-1-piperidinylthiocarbamoylthio)acetyl]pheno-
thiazine (4c)
IR: ν = 1684 cm–1 (C=O), 1230 (C=S).– 1H NMR: δ = 0.84 (d, 3H, CH3),
0.98–1.66 (m, 5H, pipd. 3-H, 4-H, 5-H), 2.47 (s, 3H, SCH3), 4.30, 5.05 (t,
br.s, 2H each, pipd. 2-H, 6-H), 4.36 (s, 2H, SCH2), 7.16–7.63 (m, 7H,
arom.).– 13C NMR proton decoupled-DEPT 135: δ = 14.83 (SCH3), 20.89
(C-CH3), 29.73 (pipd. C-4), 31.92, 32.13 (pipd. C-3, C-5), 40.18 (SCH2),
47.92, 48.09 (pipd. C-2, C-6), 124.33 (phenot. C-1), 124.69 (phenot. C-9),
125.32 (phenot. C-3), 127.01 (phenot. C-7), 127.31 (phenot. C-8), 127.72
(phenot. C-6), 127.94 (phenot. C-4), 128.38 (phenot. C-4a), 129.78 (phenot.
N-(3-Methylthiophenyl)-N-[(4-benzyl-1-piperidinylthiocarbamoylthio)-
acetyl] phenylamine (5f)
IR: ν = 1678 cm–1 (C=O), 1241 (C=S).– 1H NMR: δ = 1.05, 1.58 (q, d, 2H
each, pipd. 3-H, 5-H), 1.77–1.83 (m, 1H, pipd. 4-H), 2.36 (s, 3H, SCH3), 2.43
(s, 2H, benzyl-CH2), 3.95 (s, 2H, SCH2 ), 4.33, 5.08 (2 br.s, 2H each, pipd.
2-H, 6-H), 7.05-7.48 (m, 14H, arom.).
N-(3-Methylthiophenyl)-N-[(4-morpholinylthiocarbamoylthio)acetyl]-
phenylamine (5g)
———
1)
IR: ν = 1680 cm–1 (C=O), 1233 (C=S).– 1H NMR: δ = 2.36 (s, 3H, SCH3),
3.54 (t, 4H, mor. 3-H, 5-H), 3.85, 4.06 (2 br.s, 2H each, mor. 2-H, 6-H), 3.99
Abbreviations: phenot.: phenothiazine, arom.: aromatic, pyr.: pyrolidine,
pipd.: piperidine, pipz.: piperazine, mor.: morpholine
Arch. Pharm. Pharm. Med. Chem. 332, 422–426 (1999)

426
Karali and co-workers
(s, 2H, SCH2), 7.03–7.46 (m, 9H, arom.). 13C-NMR proton decoupled-DEPT
135: δ = 14.47 (SCH3), 40.69 (SCH2), 65.42 (mor. C-2, C-3, C-5, C-6),
125.63, 126.87, 127.84, 128.72 (=CH), 139.59 (C=C), 166.12 (s, C=O),
195.02 (s, C=S).– EIMS; m/z (%) = 418 (1) [M+], 289 (5), 215 (43), 204 (66),
130 (100), 91 (7), 86 (46).
segments were incubated with increasing concentrations of the compounds
(10–8–10–4 M) for 15 min, sequentially and concentration-response curve of
histamine was repeated as described in rat fundus strips. Each segment was
exposed to only one compound.
All compouds were dissolved in dimethyl sulfoxide (DMSO), diluted
freshly in DMSO and added to the organ bath in volumes of 50 µl. DMSO
was determined to have no direct effect on the contractions of histamine and
acetylcholine. No change in colour or participitation were observed in the
organ bath during bioassay. Stock solutions of histamine and acetylcholine
were prepared in 0.001 N HCl whereas mepyramine and atropine in distilled
water. Dilutions were made by Krebs or Tyrode solution on the day of each
experiment.
Results are given as mean ± s.e. of the means and n refers the number of
animals studied. Inhibition of histamine and acetylcholine induced contrac-
tions in the presence of the compounds are expressed as percent reductions
(% inhibition) in the control responses of these contractile agents in that
fundus strip. Contractions to histamine and acetylcholine are expressed
according to KCl (40 mM) induced contraction in that fundus strip. The
effective concentrations of the contractile agonists that elicited 50% of the
maximal response (EC50 values) were calculated for each concentration-re-
sponse curve by probit analysis and expressed as –logM. pA2 values of the
compounds and mepyramine in guinea-pig ileum are calculated by Schild
analysis. Statistical analyses were performed by Student’s t-test and one way
of variance (ANOVA) where appropriate. A p value less than 0.05 was
considered significant.
Pharmacology
Antihistaminic and Anticholinergic Activities
Experiments were performed on rat fundus strips and on guinea-pig ileum.
Fundus strips were obtained from Wistar albino rats of either sex weighing
200–250 g. Animals were sacrified by cervical dislocation and gastric fundus
was immediately removed. The gastric fundus strips were prepared as
described by Vane [13] and mounted in a 10 ml jacketed organ bath at 37 0C
containing Krebs solution of the following composition (mM): NaCl (118.5),
.
KCl (4.8), CaCl2 (1.9), KH2PO4 (1.2), MgSO4 7H2O (1.2,) NaHCO3 (25),
and glucose (10.1). Krebs solution was aerated with 95% O2 and 5% CO2.
One end of the fundus strip was fixed on the platin hook in the organ bath
and the other was connected to a force displacement trasducer placed on a
micrometer (Grass Model FTO3) for the measurement of isometric force.
The preparations were allowed to equilibrate for 1 h under 1 g of resting
tension which was determined to be optimal for maximal KCl (40 mM)
contraction. At the end of the equilibration period the viability of the fundus
strips were checked by KCl (40 mM) and preparations which developed a
tension of less than 1g were discarded. Four strips were prepared from each
fundus specimen.
References
Ileum segments were obtained from male guinea-pigs weighing 250–300g.
After animals were sacrified by cervical dislocation, the ileum 8–10 cm
proximal to the ileocaecal junction were immediately removed. Segments
2–2.5 cm long were mounted vertically in the organ bath system described
above. Tyrode solution of the following composition at 37 °C was used in
these experiments (mM): NaCl (137), KCl (2.7), CaCl2 (1.8), NaH2PO4
(0.42), MgCl2 (1.05), NaHCO3 (11.9), and glucose (5.55). At a resting
tension of 1g , ileum segments were allowed to equilibrate for 60 min with
regular washes every 15 min and then challenged with KCl (40 mM).
[1] T. N. Riley, J. DeRuiter, Histamine and antihistaminic agents. In:
Wilson and Gisvold’s Textbook of Organic Medicinal and Pharmaceu-
tical Chemistry(Eds.: J. N. Delgado, W. A. Remers), Lippincott-Raven,
New York, 1998, chapter 21.
[2] C. Safak, H. Erdogan, M. Ertan, R. Sunal, Arch. Pharm. (Weinheim)
1988, 321, 859–861.
[3] V. T. Zsolnai, Arzneim.-Forsch. / Drug Res. 1971, 21, 121–127.
[4] H. Schönenberger, P. Lippert, Pharmazie 1972, 27, 139–145.
Rat Fundus Strips
The experiments were performed to evaluate the antihistaminic and an-
ticholinergic activities of some 4 and 5 in comparison with H1-receptor
antagonist mepyramine and nonselective cholinergic antagonist atropine. For
the purpose the cumulative concentration-response curves to histamine
(10–8–10–4 M) and acetylcholine (10–8–10–4 M) were constructed in separate
[5] J. A. Vida, Central nervous system depressants: Sedative-hypnotics. In:
Principles of Medicinal Chemistry (Eds.: W. O. Foye, T. L. Lemke, D.
A. Williams), Williams and Wilkins, Baltimore, 1995, chapter 10.
[6] S. Büyüktimkin, Sci Pharm. 1984, 52, 296–300.
fundus strips. Afterwards, strips were incubated with 10–6 M or 10–4
M
[7] A. M. M. E. Omar, S. A. Osman, Pharmazie 1973, 28, 30–31.
concentrations of the compounds in the antihistaminic and anticholinergic
activities experiments, respectively. At the end of the incubation period of
15 min histamine and acetylcholine concentration-response curves were
repeated in the presence of the compounds. Each fundus strip preparation
was exposed to only one compound. 4g and 5g were studied in a concentra-
tion-dependent manner (10–9–10–4 M). In these experiments exposure of the
strips to each histamine or acetylcholine concentrations were followed by
several washes and 30 min rest before the administration of the next concen-
tration. In some experiments fundus strips were incubated with mepyramine
(10–6 and 10–4 M) and atropine (10–4 M) for 15 min prior to administration
of histamine and acetylcholine, respectively.
[8] V. K. U. Ahluwalia Dutta, H. R. Sharma, Indian J Chem. Sect B, 1987,
26B, 88–90.
[9] Ö. Ates, N. Cesur, H. Güner, M. Uzun, M, Kiraz, D. Kaya, Farmaco
1995, 50, 361–364.
[10] R. M. Silverstein, G. C. Bassler, T. C. Morril, 13C-nmr spectroscopy.
In: Spectrometric Identification of Organic Compounds, John Wiley
and Sons, New York, 1981, chapter 5.
[11] C. Safak, H. Erdogan, A. Yesilada, K. Erol, I. Cimgi, Arzneim.-Forsch./
Drug Res. 1992, 42, 123–126.
[12] G. Çapan, N. Ergenç, S. Büyüktimkin, N. Yulug, Sci. Pharm. 1993, 61,
Guinea-pig Ileum
243–250
The experiments were performed to compare antihistaminic activities of
the compouds . For the purpose cumulative concentration-response curve to
histamine (10–9–10–4 M) were constructed in separate ileum segments. Ileum
[13] J. R. Vane, Br. J. Pharmacol. 1957, 12, 344–349.
Received: May 6, 1999 [FP395]
Arch. Pharm. Pharm. Med. Chem. 332, 422–426 (1999)