5-Amino-3-(2-aminopropyl)-1,2,4-thiadiazoles as the basis of hybrid multifunctional compounds

Article abstract of DOI:10.1007/s11172-014-0563-1

An approach to the synthesis of hybrid multifunctional compounds starting from 1,2,4-thiadiazoles containing an amino group in the side chain was developed.

Full text of DOI:10.1007/s11172-014-0563-1

Russian Chemical Bulletin, International Edition, Vol. 63, No. 5, pp. 1148—1152, May, 2014
1148
5ꢀAminoꢀ3ꢀ(2ꢀaminopropyl)ꢀ1,2,4ꢀthiadiazoles as the basis
of hybrid multifunctional compounds
A. N. Proshin, I. V. Serkov, L. N. Petrova, and S. O. Bachurin
Institute of Physiologically Active Compounds, Russian Academy of Sciences,
1 prosp. Severnyi, 142432 Chernogolovka, Moscow Region, Russian Federation.
Fax: +7 (496) 524 9508. Eꢀmail: proshin@ipac.ac.ru
An approach to the synthesis of hybrid multifunctional compounds starting from 1,2,4ꢀthiꢀ
adiazoles containing an amino group in the side chain was developed.
Key words: 1,2,4ꢀthiadiazoles, aryl isothiocyanate, 3ꢀaminoꢀ5ꢀmethylisoxazole, thiourea,
Boulton—Katritzky rearrangement, neuroprotective activity.
A traditional strategy for the design of highly effective
drugs in medicinal chemistry is to achieve the maximum
selectivity of the drug which acts on an individual drug
target.1 The combination of exclusivity and selectivity was
briefly expressed by Paul Ehrlich in his concept of the
"magic bullet". According to this concept, a pharmaceutiꢀ
cal agent, meeting the "magic bullet" criterion, should act
on a single selected target and have an expected and deꢀ
sired effect on it. After that the agent should be eliminated
from the target, metabolized, and removed from the
body without additional influence on the body funcꢀ
tions.2 However, highly selective medicines acting on the
selected target, for instance, on cancer cells, are often
removed from the market due to revealed side effects.
Moreover, a steady increase in the number of highly selecꢀ
tive medicines leads to the rise of the number of medicines
prescribed to every patient. Consequently, the probability
of undesirable side effects caused by excessive pharmaceuꢀ
tical load on metabolic and drug excretion systems inꢀ
creases. The risk of drug incompatibility in the case of
their simultaneous use also increases. All the facts made
us search for an alternative to a "magic bullet".
moiety have interesting biological properties, they are highꢀ
ly potential as promising medicines and are already at
different stages of preclinical and clinical trials.5 For exꢀ
ample, compound KC 12291 (2) shows high cardioꢀ
protective activity.6 The ability of 5ꢀaminoꢀ1,2,4ꢀthiadiaꢀ
zole derivatives (3) to influence the ꢀamyloid formation7
and to modulate ꢀsecretase8 is also reported. Therefore,
these compounds can be used in the treatment of Alzꢀ
heimer´s disease, cerebral amyloid angiopathy, multiꢀinfꢀ
arct dementia, and other neurodegenerative diseases.
We developed a method for the synthesis of 5ꢀaminoꢀ
1,2,4ꢀthiadiazole derivatives, viz., 5ꢀaminoꢀ3ꢀ(2ꢀaminoꢀ
propyl)ꢀ1,2,4ꢀthiadiazoles, as starting materials for the
synthesis of hybrid compounds containing the thiadiazole
pharmacophore.9 Starting Nꢀsubstituted 5ꢀaminoꢀ3ꢀ(2ꢀ
oxopropyl)ꢀ1,2,4ꢀthiadiazoles (4) were synthesized by the
A concept of multifunctional (or multiligand) drugs
having a broad spectrum of action and capable of acting
on several targets, i.e. a combination of two or more
pharmacophore groups in one molecule, can be considꢀ
ered as an alternative owing to the ability of such mediꢀ
cines to supplement and intensify each other activity. In
the past years, the line of research associated with the
introduction of the NOꢀdonor fragment3 into the moleꢀ
cule has been extensively developed.
1,2,4ꢀThiadiazole derivatives are of great interest beꢀ
cause of their various biological activity. Nowadays, the
commercial antibiotic cefozopram (1) containing the
1,2,4ꢀthiadiazole moiety4 is used in pharmacopoeia. Beꢀ
sides, many compounds containing the 1,2,4ꢀthiadiazole
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1148—1152, May, 2014.
1066ꢀ5285/14/6305ꢀ1148 © 2014 Springer Science+Business Media, Inc.

5ꢀAminoꢀ3ꢀ(2ꢀaminopropyl)ꢀ1,2,4ꢀthiadiazoles
Russ.Chem.Bull., Int.Ed., Vol. 63, No. 5, May, 2014
1149
Scheme 1
reaction of various substituted aryl isothiocyanates (1) with
3ꢀaminoꢀ5ꢀmethylisoxazole (2) (Scheme 1). Isoxazoleꢀ
containing thioureas 3 formed in this way are subjected to
the Boulton—Katritzky rearrangement to form 1,2,4ꢀthiaꢀ
diazoles. The rearrangement involves the nucleophilic atꢀ
tack of the thiocarbonyl group on the N—O bond of the
isoxazole ring, the cleavage of this bond, and the subseꢀ
quent recyclization to the thiadiazole ring to form Nꢀsubꢀ
stituted 5ꢀaminoꢀ3ꢀ(2ꢀoxopropyl)ꢀ1,2,4ꢀthiadiazole (4).
The easily modified keto group that is present in the
synthesized 1,2,4ꢀthiadiazoles 4 gives an opportunity to
further modify the basic structure via the introduction of
various pharmacophore groups. For instance, the reacꢀ
tion of 1,2,4ꢀthiadiazole 4 with amines 5 in methanol
affords enamines 6a—h (Table 1) in almost quantitative
yield. It should be noted that these compounds exist not as
rat brain.10 It is known that glutamate receptors in the
central nervous system play an important role in the deꢀ
velopment of normal neurophysiological processes, as well
as in the pathogenesis of a number of neurodegenerative
diseases.11 In this connection, the evaluation of the ability
of compounds to influence calcium currents mediated by
glutamate receptors makes it possible to estimate their
total biological potential as possible neuroprotectors (in
the case of inhibition) or cognitive function stimulators
(in the case of activation).
The ability of synthesized enamines 6a—h and amino
derivatives 7a—h to inhibit glutamateꢀinduced 45Ca2+ capꢀ
ture in synaptosomes from rat cerebral cortex was studied.
Our investigations showed that the synthesized compounds
1
Table 1. Enamines 6a—h and 5ꢀaminoꢀ3ꢀ(2ꢀaminopropyl)ꢀ1,2,4ꢀ
thiadiazoles 7a—h
imines 6´ but in enamine form 6 according to H NMR.
The spectra of these compounds show a signal from one
proton at the double bond at 5.15—5.20, rather than a
signal from two protons at  3.5 as would be in the case of
imine form 6´.
Enamines 6a—h isolated by filtration were suspended
in methanol and hydrogenated by sodium borohydride at
40—50 С until the starting enamine was dissolved. This
procedure afforded amino derivatives 7a—h. To sum up,
we synthesized compounds containing an amino group,
which can be used for further modification of the moleꢀ
cule. These compounds may be used as the starting
materials for the synthesis of hybrid multifunctional
compounds.
Compound
6a, 7a
R1
R2
3ꢀClꢀ4ꢀF
3ꢀClꢀ4ꢀF
3ꢀClꢀ4ꢀF
3,4ꢀCl2
6b, 7b
6c, 7c
6d, 7d
6e, 7e
6f, 7f
4ꢀMe
4ꢀBr
For the preliminary estimation of biological activity of
the synthesized compounds, we investigated the influence
of the compounds on glutamateꢀinduced calcium ion capꢀ
ture using the synaptosomal Р2 fraction prepared from the
6g, 7g
6h, 7h
4ꢀF
3,4ꢀCl2

1150
Russ.Chem.Bull., Int.Ed., Vol. 63, No. 5, May, 2014
Proshin et al.
Table 2. Influence of the synthesized compounds on 45Са2+ capꢀ
ture in rat cortical synaptosomes using glutamate stimulation
ed to 40—50 С. Sodium borohydride (1.5 equiv.) was added to
the mixture, and the latter was stirred for 2 h. The suspension
gradually dissolved. After the completion of the reaction, the
mixture was cooled, methanol was evaporated, and the residue
was diluted with water (20 mL) and extracted with dichloꢀ
romethane (3×10 mL). Organic extracts were combined, dried
over sodium sulfate, and filtered off. The filtrate was evaporated,
and the residue was recrystallized. As a result, {3ꢀ[2ꢀ(alkylꢀ
amino)propyl]ꢀ[1,2,4]thiadiazolꢀ5ꢀyl}phenylamines 7a—h were
obtained.
Comꢀ
pound
Enamines 6а—h
Amines 7а—h
Кa
IC50
Кa
IC50
b
b
a
b
c
d
e
f
49.8 9.7
76.9 11.1
65.1 13.9
26.0 0.3
81.8 5.1
70.0 4.1
68.3 6.0
15.0 3.0
114.8
—
—
45.7
—
—
4.7 1.9
28.05 11.1
35.1 6.1
61.7
64.6
85.1
—
—
—
177 14.4
Nꢀ(3ꢀChloroꢀ4ꢀfluorophenyl)ꢀ{3ꢀ[2ꢀ(4ꢀmethylbenzylamino)ꢀ
propꢀ1ꢀenyl][1,2,4]thiadiazolꢀ5ꢀyl}amine (6a). Colorless crystals,
m.p. 164—166 С, 91% yield. Found (%): С, 58.36; H, 4.32;
N, 14.81. C19H18ClFN4S. Calculated (%): С, 58.68; H, 4.67;
128.4 0.1
164.2 7.3
112.3 12.4
304.6 17.7
g
h
—
38.0
—
—
1
N, 14.41. H NMR (200 MHz, CDCl3), : 2.03 (s, 3 H, СH3);
2.38 (s, 3 H, ArCH3); 4.49 (d, 2 H, ArCH2, J = 6.3 Hz); 5.21
(s, 1 H, СН=C); 7.20 (m, 6 H, Нarom); 7.42 (m, 1 H, Нarom);
8.71 (t, 1 H, NHCH2, J = 6.3 Hz).
aК is the percentage of captured 45Са2+ in rat cortical synaptoꢀ
somes of the control group (control is 100%).
b IC50 was determined for active compounds (K < 50).
Nꢀ(3ꢀChloroꢀ4ꢀfluorophenyl)ꢀ[3ꢀ(2ꢀbenzylaminopropꢀ1ꢀenyl)ꢀ
[1,2,4]thiadiazolꢀ5ꢀyl]amine (6b). Lightꢀyellow powder, m.p.
155—157 С, 92% yield. Found (%): С, 57.95; H, 4.42; N, 14.35.
C18H16ClFN4S. Calculated (%): С, 57.57; H, 4.30; N, 14.95.
1H NMR (200 MHz, CDCl3), : 2.02 (s, 3 H, СCH3); 4.53 (d, 2 H,
ArCH2, J = 6.3 Hz); 5.19 (s, 1 H, СН=C); 7.17 (m, 2 H, Нarom),
7.36 (m, 6 H, Нarom); 8.77 (t, 1 H, NHCH2, J = 6.3 Hz).
Nꢀ(3ꢀChloroꢀ4ꢀfluorophenyl)ꢀ{3ꢀ[2ꢀ(4ꢀmethoxybenzylamino)ꢀ
propꢀ1ꢀenyl][1,2,4]thiadiazolꢀ5ꢀyl}amine (6с). Lightꢀyellow
powder, m.p. 146—148 С, 89% yield. Found (%): С, 55.92; H,
4.41; N, 14.09. C19H18ClFN4OS. Calculated (%): С, 56.36; H,
can modulate glutamateꢀinduced 45Ca2+ capture (Table 2).
Enamines 6a—h weakly inhibited 45Ca2+ capture. The acꢀ
tivity of amino derivatives 7a—h strongly depends on the
structure of the substituents R1 and R2. Benzyl derivatives
7a—с, particularly compound 7а, show quite good inhibiꢀ
tory activity. By contrast, compounds 7d—h bearing morꢀ
pholine or tetramethylpiperidine as a substituent act as
45Ca2+ capture stimulators.
To sum up, we developed a convenient synthetic method
and synthesized a number of new diamino derivatives of
1,2,4ꢀthiadiazole. These compounds can be used as the
starting materials for the synthesis of a new class of promꢀ
ising neuroprotectors.
1
4.48; N, 13.84. H NMR (200 MHz, CDCl3), : 2.02 (s, 3 H,
СCH3); 3.85 (s, 3 H, ОCH3); 4.47 (d, 2 H, ArCH2, J = 6.3 Hz);
5.16 (s, 1 H, СН=C); 6.91 (d, 2 H, Нarom, J = 8.5 Hz); 7.18 (m, 2 H,
Нarom); 7.25 (d, 2 H, Нarom, J = 8.5 Hz); 7.41 (m, 1 H, Нarom);
8.70 (t, 1 H, NHCH2, J = 6.3 Hz); 9.35 (br. s, 1 H, ArNH).
Nꢀ(3,4ꢀDichlorophenyl)ꢀ{3ꢀ(2ꢀ[2ꢀ(morpholinꢀ4ꢀyl)ethylamino]ꢀ
propꢀ1ꢀenyl)[1,2,4]thiadiazolꢀ5ꢀyl}amine (6d). Lightꢀyellow
crystals, m.p. 179—181 С, 90% yield. Found (%): С, 49.11;
H, 5.21; N, 16.76. C17H21Cl2N5OS. Calculated (%): С, 49.28;
H, 5.11; N, 16.97. 1H NMR (200 NHz, CDCl3), : 2.00 (s, 3 H,
СCH3); 2.42 (m, 6 H, N(СН2)2, NСН2); 3.33 (m, 2 H, NНСН2);
3.56 (t, 4 H, О(СН2)2, J = 4.7 Hz); 5.10 (s, 1 H, СН=C); 7.43
Experimental
1
H NMR spectra were recorded on a Bruker СХРꢀ200 specꢀ
trometer (Germany) using Me4Si as an internal standard. Meltꢀ
ing points were determined on a Boetius heating table and are
uncorrected. The solutions were concentrated on a rotary evapꢀ
orator using a vacuum jet water pump. Elemental analysis of the
synthesized compounds was performed on a CarloꢀErba CHNꢀ
analyzer.
(dd, 1 H, Нarom, J = 2.6 Hz, J = 8.8 Hz); 7.59 (d, 1 H, Нarom
,
J = 8.8 Hz); 8.01 (d, 1 H, Нarom, J = 2.6 Hz); 8.47 (t, 1 H,
NHCH2, J = 5.1 Hz); 10.82 (s, 1 H, ArNH).
Nꢀ[1ꢀ(5ꢀрꢀTolylamino[1,2,4]thiadiazolꢀ3ꢀyl)propꢀ1ꢀenꢀ2ꢀ
yl]ꢀ(2,2,6,6ꢀtetramethylpiperidinꢀ4ꢀyl)amine (6е). Yellow crysꢀ
tals, m.p. 158—160 С, 88% yield. Found (%): С, 65.67; H, 8.17;
N, 18.17. C21H31N5S. Calculated (%): С, 65.42; H, 8.10; N, 18.16.
1H NMR (200 MHz, DMSOꢀd6), : 1.08 (t, 2 H, С(3)НН,
С(5)НН, J = 12.0 Hz); 1.11 and 1.22 (both s, 12 H, 2 (CH3)2);
1.84 (dd, 2 H, С(3)НН, С(5)НН, J = 2.8 Hz, J = 12.6 Hz); 2.05
(s, 3 H, CCH3); 2.33 (s, 3 H, ArCH3); 3.76 (m, 1 H, C(4)H);
4.97 (s, 1 H, СН=C); 7.09 and 7.38 (both d, 4 H, Нarom, J= 8.4 Hz);
8.03 (d, 1 H, NHC(4)Н, J = 8.8 Hz); 10.35 (br. s, 1 Н, ArNH).
Nꢀ{1ꢀ[5ꢀ(4ꢀBromophenylamino)[1,2,4]thiadiazolꢀ3ꢀyl]propꢀ
1ꢀenꢀ2ꢀyl}ꢀ(2,2,6,6ꢀtetramethylpiperidinꢀ4ꢀyl)amine (6f). White
crystals, m.p. 180—182 С, 92% yield. Found (%): С, 53.49; H, 6.42;
N, 15.24. C20H28BrN5S. Calculated (%): С, 53.33; H, 6.27;
N, 15.55. 1H NMR (200 MHz, DMSOꢀd6), : 0.90 (t, 2 H, С(3)НН,
С(5)НН, J = 12.0 Hz); 1.07 and 1.18 (both s, 12 H, 2 (CH3)2);
1.81 (dd, 2 H, С(3)НН, С(5)НН, J = 2.3 Hz, J = 12.1 Hz); 2.04
Synthesis of {3ꢀ[2ꢀ(alkylamino)propyl]ꢀ[1,2,4]thiadiazolꢀ5ꢀ
y}phenylamines (7a—h) (general procedure). A solution of aryl
isothiocyanate 1 (0.01 mol) in acetonitrile (10 mL) was added
dropwise with stirring to a solution of 3ꢀaminoꢀ5ꢀmethylisoxꢀ
azole 2 (0.01 mol) in acetonitrile (20 mL). The mixture was
brought to a boil and allowed to stand at room temperature until
5ꢀarylaminoꢀ3ꢀ(2ꢀoxopropyl)ꢀ[1,2,4]thiadiazole 4 precipitated,
and the latter was filtered off. If the crystals were not formed, the
reaction mixture was concentrated and the resulting oil was tritꢀ
urated in diethyl ether. 1,2,4ꢀThiadiazole 4 (0.01 mol) was disꢀ
solved in methanol (10 mL), and a solution of amine 5 (0.01 mol)
in methanol (10 mL) was added dropwise to the mixture while
stirring. The reaction mixture was stirred at room temperature
for 2—5 h until the precipitate formed. The precipitate of enamꢀ
ine 6a—h was filtered off, washed with methanol, and dried. The
resulting enamine was suspended in methanol (20 mL) and heatꢀ

5ꢀAminoꢀ3ꢀ(2ꢀaminopropyl)ꢀ1,2,4ꢀthiadiazoles
Russ.Chem.Bull., Int.Ed., Vol. 63, No. 5, May, 2014
1151
(s, 3 H, CCH3); 3.73 (m, 1 H, C(4)H); 5.03 (s, 1 H, СН=C);
7.55 (s, 4 H, Нarom); 8.00 (d, 1 H, NHC(4)Н, J = 8.8 Hz).
Nꢀ{1ꢀ[5ꢀ(4ꢀFluorophenylamino)[1,2,4]thiadiazolꢀ3ꢀyl]propꢀ
1ꢀenꢀ2ꢀyl}ꢀ(2,2,6,6ꢀtetramethylpiperidinꢀ4ꢀyl)amine (6g). Yellow
crystals, m.p. 123—125 С, 88% yield. Found (%): С, 61.53;
H, 7.39; N, 17.68. C20H28FN5S. Calculated (%): С, 61.67;
Nꢀ[1ꢀ(5ꢀрꢀTolylamino[1,2,4]thiadiazolꢀ3ꢀyl)propanꢀ2ꢀyl]ꢀ
(2,2,6,6ꢀtetramethylpiperidinꢀ4ꢀyl)amine (7е). Yellow crystals,
m.p. 62—64 С, 65% yield. Found (%): С, 65.42; H, 8.76;
N, 17.91. C21H33N5S. Calculated (%): С, 65.08; H, 8.58;
1
N, 18.07. H NMR (200 MHz, DMSOꢀd6), : 0.71 (m, 2 H,
С(3)НН, С(5)НН), 1.02 and 1.05 (both s, 6 H, 2 CH3); 1.07 (d, 3 H,
СН2CHCH3, J = 6.5 Hz); 1.12 and 1.14 (both s, 6 H, 2 CH3);
1.75 (dd, 2 H, С(3)НН, С(5)НН, J = 3.1 Hz, J = 12.5 Hz); 2.34
(s, 3 H, ArꢀCH3); 2.73 (dd, 2 H, СН2CHМе, J = 2.3 Hz,
J = 6.5 Hz); 2.91 (m, 1 H, C(4)H); 3.32 (m, 1 H, СН2CHМе);
7.09 and 7.38 (both d, 4 H, Нarom, J = 8.6 Hz); 10.56 (br. s,
1 Н, ArNH).
1
H, 7.25; N, 17.98. H NMR (200 MHz, DMSOꢀd6), : 0.96
(t, 2 H, С(3)НН, С(5)НН, J = 12.0 Hz); 1.06 and 1.17 (both s,
12 H, 2 (CH3)2); 1.80 (d, 2 H, С(3)НН, С(5)НН, J = 12.0 Hz);
2.03 (s, 3 H, CCH3); 3.73 (m, 1 H, C(4)H); 5.02 (s, 1 H, СН=C);
7.22 (m, 2 H, Нarom); 7.57 (m, 2 H, Нarom); 8.02 (d, 1 H,
NHC(4)Н, J = 8.8 Hz).
Nꢀ{1ꢀ[5ꢀ(3,4ꢀDichlorophenylamino)[1,2,4]thiadiazolꢀ3ꢀyl]ꢀ
propꢀ1ꢀenꢀ2ꢀyl}ꢀ(2,2,6,6ꢀtetramethylpiperidinꢀ4ꢀyl)amine (6h).
White powder, m.p. 130—132 С, 90% yield. Found (%): С, 54.81;
H, 6.29; N, 15.47. C20H27Cl2N5S. Calculated (%): С, 54.54;
H, 6.18; N, 15.90. 1H NMR (200 MHz, CDCl3), : 1.13 (t, 2 H,
С(3)НН, С(5)НН, J = 12.0 Hz); 1.20 and 1.29 (both s, 12 H,
2 (CH3)2); 1.97 (dd, 2 H, С(3)НН, С(5)НН, J = 3.5 Hz,
J = 12.8 Hz); 2.10 (s, 3 H, CCH3); 3.78 (m, 1 H, C(4)H); 5.14
(s, 1 H, СН=C); 7.16 (dd, 1 H, Нarom, J = 2.8 Hz, J = 8.8 Hz); 7.46
(d, 1 H, Нarom, J = 8.8 Hz); 7.49 (d, 1 H, Нarom, J = 2.8 Hz);
7.50 (s, 1 H, Нarom); 8.19 (d, 1 H, NHC(4)Н, J = 8.8 Hz).
Nꢀ(3ꢀChloroꢀ4ꢀfluorophenyl)ꢀ{3ꢀ[2ꢀ(4ꢀmethylbenzylamino)ꢀ
propyl][1,2,4]thiadiazolꢀ5ꢀyl}amine (7a). White powder, m.p.
90—92 С, 67% yield. Found (%): С, 58.22; H, 5.26; N, 14.37.
C19H20ClFN4S. Calculated (%): С, 58.38; H, 5.16; N, 14.33.
1H NMR (200 MHz, CDCl3), : 1.21 (d, 3 H, СН2CHCH3,
J = 6.3 Hz); 2.33 (s, 3 H, ArCH3); 2.90 (dd, 1 H, СННCHМе,
J = 6.0 Hz, J = 14.4 Hz); 3.01 (dd, 1 H, СННCHМе, J = 6.7 Hz,
J = 14.2 Hz); 3.28 (sext, 1 H, СН2CHМе, J = 6.3 Hz); 3.77 and
3.89 (both d, 2 H, ArCHН, J = 13.0 Hz); 7.17 (m, 5 H, Нarom);
7.29 (m, 1 H, Нarom); 7.41 (m, 1 H, Нarom).
Nꢀ{1ꢀ[5ꢀ(4ꢀBromophenylamino)[1,2,4]thiadiazolꢀ3ꢀyl]propꢀ
anꢀ2ꢀyl}ꢀ(2,2,6,6ꢀtetramethylpiperidinꢀ4ꢀyl)amine (7f). Yellow
powder, m.p. 78—80 С, 72% yield. Found (%): С, 53.28; H, 6.56;
N, 15.64. C20H30BrN5S. Calculated (%): С, 53.09; H, 6.68;
1
N, 15.48. H NMR (200 MHz, DMSOꢀd6), : 0.73 (m, 2 H,
С(3)НН, С(5)НН); 1.02 and 1.05 (both s, 6 H, 2 CH3); 1.08
(d, 3 H, СН2CHCH3, J = 6.5 Hz); 1.11 and 1.13 (both s, 6 H,
2 CH3); 1.72 (dd, 2 H, С(3)НН, С(5)НН, J = 3.1 Hz, J = 12.5 Hz);
2.75 (dd, 2 H, СН2CHМе, J = 2.3 Hz, J = 6.5 Hz); 2.91 (m, 1 H,
C(4)H); 3.33 (m, 1 H, СН2CHМе); 7.40 and 7.52 (both d, 4 H,
Нarom, J = 8.8 Hz).
Nꢀ{1ꢀ[5ꢀ(4ꢀFluorophenylamino)[1,2,4]thiadiazolꢀ3ꢀyl]propꢀ
anꢀ2ꢀyl}ꢀ(2,2,6,6ꢀtetramethylpiperidinꢀ4ꢀyl)amine (7g). Yellow
powder, m.p. 68—70 С, 69% yield. Found (%): С, 61.23; H, 7.87;
N, 17.92. C20H30FN5S. Calculated (%): С, 61.35; H, 7.72;
1
N, 17.89. H NMR (200 MHz, DMSOꢀd6), : 0.71 (m, 2 H,
С(3)НН, С(5)НН); 1.02 and 1.04 (both s, 6 H, 2 CH3); 1.07
(d, 3 H, СН2CHCH3, J = 6.6 Hz); 1.11 and 1.13 (both s, 6 H,
2 CH3); 1.72 (dd, 2 H, С(3)НН, С(5)НН, J = 3.0 Hz, J = 12.6 Hz);
2.72 (dd, 2 H, СН2CHМе, J = 2.3 Hz, J = 6.6 Hz); 2.91 (m, 1 H,
C(4)H); 3.34 (m, 1 H, СН2CHМе); 7.04 (t, 2 H, Нarom
,
Nꢀ(3ꢀChloroꢀ4ꢀfluorophenyl)ꢀ[3ꢀ(2ꢀbenzylaminopropyl)[1,2,4]ꢀ
thiadiazolꢀ5ꢀyl]amine (7b). White powder, m.p. 82—84 С, 65%
yield. Found (%): С, 58.93; H, 4.37; N, 14.72. C18H18ClFN4S.
Calculated (%): С, 58.68; H, 4.67; N, 14.41. 1H NMR (200 MHz,
CDCl3), : 1.21 (d, 3 H, СН2CHCH3, J = 6.5 Hz); 2.87 (dd,
1 H, СННCHМе, J = 6.0 Hz, J = 14.4 Hz); 3.01 (dd, 1 H,
СННCHМе, J = 6.7 Hz, J = 14.2 Hz); 3.27 (sext, 1 H,
СН2CHМе, J = 6.3 Hz); 3.79 and 3.91 (both d, 2 H, ArCHН,
J = 13.0 Hz); 7.22 (m, 7 H, Нarom); 7.42 (m, 1 H, Нarom).
Nꢀ(3ꢀChloroꢀ4ꢀfluorophenyl)ꢀ{3ꢀ[2ꢀ(4ꢀmethoxybenzylamino)ꢀ
propyl][1,2,4]thiadiazolꢀ5ꢀyl}amine (7с). White powder, m.p.
93—95 С, 63% yield. Found (%): С, 56.30; H, 4.78; N, 13.91.
C19H20ClFN4OS. Calculated (%): С, 56.08; H, 4.95; N, 13.77.
1H NMR (200 MHz, CDCl3), : 1.22 (d, 3 H, СН2CHCH3,
J = 6.5 Hz); 2.85 (dd, 1 H, СННCHМе, J = 6.0 Hz, J = 14.4 Hz);
3.02 (dd, 1 H, СННCHМе, J = 6.7 Hz, J = 14.2 Hz); 3.25 (sext,
1 H, СН2CHМе, J = 6.3 Hz); 3.69 and 3.81 (both d, 2 H,
ArCHН, J = 13.0 Hz); 3.84 (s, 3 H, ОCH3); 6.91 (m, 2 H,
Нarom); 7.21 (m, 5 H, Нarom).
Nꢀ(3,4ꢀDichlorophenyl)ꢀ{3ꢀ(2ꢀ[2ꢀ(morpholinꢀ4ꢀyl)ethylamino]ꢀ
propyl)[1,2,4]thiadiazolꢀ5ꢀyl}amine (7d). Yellow powder, m.p.
96—98 С, 66% yield. Found (%): С, 49.39; H, 5.67; N, 16.27.
C17H23Cl2N5OS. Calculated (%): С, 49.04; H, 5.57; N, 16.82.
1H NMR (200 MHz, CDCl3), : 1.09 (d, 3 H, СН2CHCH3,
J = 6.3 Hz); 2.30 (t, 4 H, N(СН2)2, J = 4.4 Hz); 2.37 (m, 2 H,
NНСН2); 2.64 (m, 2 H, NСН2); 2.77 (m, 2 H, СН2CHМе);
3.11 (m, 1 H, СН2CHМе); 3.49 (t, 4 H, О(СН2)2, J = 4.4 Hz);
7.46 (s, 2 H, Нarom); 7.99 (s, 1 H, Нarom).
J = 8.6 Hz); 7.58 (dd, 2 H, Нarom, J = 4.7 Hz, J = 9.1 Hz).
Nꢀ{1ꢀ[5ꢀ(3,4ꢀDichlorophenylamino)[1,2,4]thiadiazolꢀ3ꢀyl]ꢀ
propanꢀ2ꢀyl}ꢀ(2,2,6,6ꢀtetramethylpiperidinꢀ4ꢀyl)amine (7h).
White powder, m.p. 90—92 С, 67% yield. Found (%): С, 54.67;
H, 6.66; N, 15.48. C20H29Cl2N5S. Calculated (%): С, 54.29;
H, 6.61; N, 15.83. 1H NMR (200 MHz, DMSOꢀd6), : 0.79 (dt,
2 H, С(3)НН, С(5)НН, J = 12.0 Hz, J = 21.2 Hz); 1.08 and 1.12
(both s, 6 H, 2 CH3); 1.15 (d, 3 H, СН2CHCH3, J = 6.6 Hz);
1.16 and 1.20 (both s, 6 H, 2 CH3); 1.84 (dd, 2 H, С(3)НН,
С(5)НН, J = 3.3 Hz, J = 12.6 Hz); 2.84 (dd, 1 H, СННCHМе,
J = 6.0 Hz, J = 14.2 Hz); 2.92 (dd, 1 H, СННCHМе, J = 4.0 Hz,
J = 14.2 Hz); 3.00 (m, 1 H, C(4)H); 3.42 (m, 1 H, СН2CHМе);
7.17 (dd, 1 H, Нarom, J = 2.2 Hz, J = 8.6 Hz); 7.45 (d, 1 H,
Нarom, J = 8.6 Hz); 7.51 (d, 1 H, Нarom, J = 2.2 Hz).
Determination of 45Са2+ capture in synaptosomes. Brain corꢀ
tical synaptosomes were isolated from newborn rats (9—10 days
old) following the standard Hajos method. The synaptosomal Р2
fraction was suspended in incubation buffer А: 132 mM NaCl,
5 mM KCl, 5 mM HEPES, 10 mM glucose, pH 7.4 (peptide
concentration 1.5—2 mg mL–1) for accumulation of a radioꢀ
active label. The calcium concentration in the resulting bulk was
1.25 mol L–1 (1.4 Ci mL–1). Glutamate (200 M) was used for
the stimulation of 45Са2+ capture in synaptosomes. After incuꢀ
bation with glutamate at 37 С for 5 min, the capture was termiꢀ
nated by filtration through a glass fiber filter (grade GF/B, Whatꢀ
man, UK). The filter was thrice washed with a cold buffer soluꢀ
tion B: 145 mM HEPES, 10 mM Tris, 5.4 mM NaꢀEDTA,
pH 7.4. All runs were carried out with three replicate samples for

1152
Russ.Chem.Bull., Int.Ed., Vol. 63, No. 5, May, 2014
Proshin et al.
two independent experiments. The samples were analyzed on
a liquid scintillation betaꢀanalyzer (TriCarb 2800, Perkin—Elꢀ
mer). An amount of 45Са2+ captured in synaptosomes was deterꢀ
mined as a label content difference with the use of glutamate
capture stimulation and without it, expressed in percentage from
the control (control was taken to be 100%). The statistical proꢀ
cessing of the results was done using Student´s t criterion.
5. A. Castro, T. Castaсo, A. Encinas, W. Porcal, C. Gil, Bioorg.
Med. Chem., 2006, 14, 1644.
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J. Meil, J. Schrader, NaunynꢀSchmiedeberg´s Arch. Pharmaꢀ
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bers, Pat. US, No. 20100120874A1.
9. A. N. Proshin, I. V. Serkov, S. O. Bachurin, Dokl. Akad.
Nauk, 2012, 446, 1, 48 [Dokl. Chem. (Engl. Transl.), 2012, 1].
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This work was financially supported in part by the Rusꢀ
sian Foundation for Basic Research (Project Nos 11ꢀ03ꢀ
00863ꢀа and 12ꢀ04ꢀ00713ꢀа).
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Received Novemver 19, 2013;
in revised form April 3, 2014