Synthesis of Immunoactive Tris(2-hydroxyethyl)ammonium 1-R-Indol-3-ylsulfanyl(sulfonyl)acetates

Article abstract of DOI:10.1134/S1070427218030205

Difficultly accessible 1-R-indol-3-ylsulfanyl(sulfonyl)acetic acids 1-R-IndYCH₂CO₂H (R = H, Me, Bn; Y = S, SO₂) 1a–Id were prepared. Their reaction with tris(2-hydroxyethyl)amine yielded tris(2-hydroxyethyl) ammonium 1-R-i

Full text of DOI:10.1134/S1070427218030205

ISSN 1070-4272, Russian Journal of Applied Chemistry, 2018, Vol. 91, No. 3, pp. 469−472. © Pleiades Publishing, Ltd., 2018.
Original Russian Text © S.N. Adamovich, A.N. Mirskova, 2018, published in Zhurnal Prikladnoi Khimii, 2018, Vol. 91, No. 3, pp. 432−435.
SPECIFIC
TECHNOLOGICAL SOLUTIONS
Synthesis of Immunoactive Tris(2-hydroxyethyl)ammonium
1-R-Indol-3-ylsulfanyl(sulfonyl)acetates
S. N. Adamovicha,b and A. N. Mirskovaa,b,
*
a Favorsky Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, ul. Favorskogo 1, Irkutsk, 664033 Russia
b Irkutsk Scientific Center, Siberian Branch, Russian Academy of Sciences, ul. Lermontova 134, Irkutsk, 664033 Russia
*e-mail: mir@irioch.irk.ru
Received February 20, 2018
Abstract—Difficultly accessible 1-R-indol-3-ylsulfanyl(sulfonyl)acetic acids 1-R-IndYCH2CO2H (R = H, Me,
Bn;Y= S, SO2) 1a–Id were prepared. Their reaction with tris(2-hydroxyethyl)amine yielded tris(2-hydroxyethyl)
ammonium 1-R-indol-3-ylsulfanyl(sulfonyl)aceetates (protatranes) 2a–2d. The immunoactive properties of 2a–2d
were studied. Protatranes 2a, 2c, and 2d proved to be effective immunosuppressive agents (up to 99.5% inhibition
of mice splenocyte proliferation in vitro).
DOI: 10.1134/S1070427218030205
Awide range of physiologically active salts and ionic
liquids were prepared previously by the reaction of bio-
genic amines (imidazoles, guanidines, alkanolamines,
etc.) with biologically active arylchalcogenylacetic ac-
ids RYCH2CO2H (R = Ar, indolyl, etc.; Y = O, S, SO,
SO2, Se) [1–3].
and also an equimolar amount of toxic hydrazine hy-
drate. The yield of 1 was 70–85%, and the purity was
92–93% [5].
This study was aimed at developing an efficient pro-
cedure for preparing compounds 1 (Scheme 1) and their
tris(2-hydroxyethyl)ammonium salts (protatranes) 2
(Scheme 2) and at evaluating their immunotropic activ-
ity (2).
The tris(2-hydroxyethyl)amine (triethanolamine) de-
rivatives, tris(2-hydroxyethyl)ammonium arylchalcog-
enylacetates ArYCH2CO2 ·НN+(CH2CH2OH)3, whose
–
Conditions: i, H2O, 30°C, 3 h, yield up to 95%, pu-
rity up to 99.7%.
cation has unique tricyclic “atrane” structure favoring
penetration of the substance through cell membranes,
are the most studied. We termed them protatranes. Prota-
tranes combining the properties of their components ex-
hibit synergistic effect and high and diverse physiological
and pharmacological activity (antioxidant, antisclerotic,
antiallergic, antitumor, antimetastatic, protective, growth-
stimulating, enzyme-stimulating effects) [2].
As shown in Scheme 1, we were able to exclude the
use of alcohol in both steps of the synthesis. The reaction
was performed in water at 30°C. Instead of I2 and KI, we
used 10–20 times cheaper Br2 and KBr (NaBr) [6], which
allows the product synthesis cost to be reduced.
Indole is brominated already at room temperature
in 3-position. The 3-bromoindole formed reacts with
thiourea to form indolylisothiouronium bromide. This
reaction route ensures increased levels of the yield and
purity of 1 due to exclusion of the formation of side oxi-
dation products (indole disulfides etc.), occurring when
using a strong oxidant, I2 + KI. The use of hydrazine
hydrate is not required. Oxidation of 1c with hydrogen
peroxide yielded 1-benzylindol-3-ylsulfonylacetic acid
1-Bn-Ind-SO2CH2CO2H (1d).
Indole derivatives, in particular, indol-3-ylsulfanyl-
acetic acids 1 and their salts, deserve particular attention
as biologically active substances and intermediates for
drug synthesis [4]. However, in contrast to aryloxyace-
tic acids (Y = O), acids 1 (Y = S) are difficultly acces-
sible. Compounds 1 were prepared previously by pro-
longed (for up to 8 h) heating (to 85°C) in toxic alcohols
(methanol, isopropanol, etc.) using expensive I2 and KI,
469

470
ADAMOVICH, MIRSKOVA
Scheme 1. Synthesis of 1-R-indol-3-ylsulfanylacetic acids.
In cooperation with the Institute of Basic and Clinical
Immunology (Novosibirsk, Russia), we have studied
the immunomodulating activity of protatranes 2а–2d,
following the known procedure [8].
Scheme 2. Tris(2-hydroxyethyl)ammonium 1-R-indol-3-
ylsulfanyl(sulfonyl)acetates (protatranes) 2a–2d.
Compounds 2a–2d exhibit dose-dependent antipro-
liferative activity and inhibit spontaneous and mitogen-
induced (concanavalin, Con A, Sigma) proliferation of
spleen cells of experimental mice (see table).
Protatranes 2a, 2c, and 2d are the most active (up
to –99.5% inhibition of cell growth) and are therefore
promising for further studies as immunosuppressive
agents. The effect of 2a, 2c, and 2d is comparable to that
of the known immunosuppressive agent, cyclosporin A.
The reaction of 1a–1d with triethanolamine yielded
tris(2-hydroxyethyl)ammonium 1-R-indol-3-ylsulfanyl-
(sulfonyl)acetates, protatranes 2a–2d (Scheme 2).
EXPERIMENTAL
The NMR spectra (solutions in D2O or CD3OD)
were recorded with a Bruker DPX-400 spectrometer
(1H, 400.13 MHz; 13С, 101.62 MHz) using HMDS as
internal reference. The IR spectra were recorded with
a Bruker IFS-25 spectrophotometer. The purity of the
compounds was determined by potentiometric titration
(EA-74 ion meter).
In contrast to the known procedure for preparing
protatranes 2 (solvent ethanol, Т = 8°C, 2–3 h, yield 80–
90%, purity 93%) [5], the reaction is performed without
a solvent; Т = 60°C, 15–30 min, yield up to 99%, purity
up to 99%.
The modern knowledge of the pathogenesis of dis-
eases associated with disturbance of immune processes
at mismatch of the regulatory effects and of the balance
of the corresponding cytokines dictates the need for de-
veloping new immunoactive drugs for treating autoim-
mune, immunocomplex, immunodeficient, lymphopro-
liferative, tumor, and allergic diseases, and also compli-
cations in transplantations of organs, bone marrow, etc.,
associated with activation–deactivation of the immune
system. Today there are no drugs that would be allowed
for medical use and be capable of selectively altering the
Th1/Th2 balance in the required direction [7].
Synthesis of 1a–1c (general procedure). A solution
of Br2 (0.01 mol) and KBr (0.01 mol) in 25 mL of H2O
was added to a suspension of the corresponding indole
(0.01 mol) and thiourea (0.02 mol) in 25 mL of H2O.
The mixture was stirred for 3 h at 30°C, after which a
solution of 0.05 mol of NaOH in 15 mL of H2O and
a solution of 0.012 mol of monochloroacetic acid in
10 mL of H2O were added. The mixture was kept for
30 min at pH 9–10, acidified with HCl (10%) to pH 1,
and kept at 5°C for 24 h. The precipitate was filtered off
and dried.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 91 No. 3 2018

SYNTHESIS OF IMMUNOACTIVE TRIS(2-HYDROXYETHYL)AMMONIUM
471
Effect of 2a–2d on spontaneous and mitogen-stimulated proliferation of intact mice spleen cells in vitro (– or +, effect relative
to control, %)a
Proliferation
Compound
Dosage, mg mL–1
spontaneous
Con A
2a
3
30
300
+8.0
–30.0
–84.0
+15.1
–31.0
–48.0
2b
2c
2d
3
30
300
+71.0
+25.0
–49.0
–4.0
+5.5
–25.4
3
30
300
–36.0
–74.5
–89.9
–19.0
–29.2
–99.5
3
30
300
–1.5
–60.4
–75.7
–17.5
–29.9
–90.9
a The control (without adding 2a–2d) is taken as 0%.
1d: yield 92%, colorless powder, mp 165°C, purity
98.6%. IR spectrum (KBr, ν, cm–1): 1380 (SO2), 1700
(С=О), 3290 (ОН). H NMR spectrum (CD3OD), δ,
ppm: 4.26 s (2Н, SО2СН2), 5.48 s (2Н, СН2–С6Н5),
7.20–8.03 m (10Н, Bnz, Ind). 13C NMR spectrum
(CD3OD), δ, ppm: 49.47 (СН2–С6Н5), 60.44 (SО2СН2),
110.33–134.43 (Bnz, Ind), 163.80 (С=О).
Synthesis of 1d. A mixture of 0.01 mol of 1c and
0.05 mol of 30% Н2О2 in 30 mL of acetic acid was
allowed to stand for 12 h. The solvent was distilled off,
and the residue was recrystallized (H2O/acetone, 45°C).
1
Synthesis of 2a–2d (general procedure). A mixture
of 0.01 mol of appropriate acid 1a–1d and 0.01 mol
of triethanolamine was stirred at 60°C for 15–30 min,
cooled, washed with diethyl ether, and dried.
2a: yield 97%, colorless powder, mp 93°C, purity
99.0%. IR spectrum (KBr, ν, cm–1): 1591 (С=О),
1a: yield 92%, colorless powder, mp 110°C, purity
99.6%. IR spectrum (KBr, ν, cm–1): 1704 (C=O), 3498
(ОН). 1H NMR spectrum (CD3OD), δ, ppm: 3.36 s (2Н,
SСН2), 7.09–7.70 m (5Н, Ind). 13C NMR spectrum
(CD3OD), δ, ppm: 39.94 (SСН2), 104.35–138.08 (Ind),
174.44 (С=О).
1
2700 (N + Н), 3308 (ОН). H NMR spectrum (D2O),
δ, ppm: 3.19 t (6Н, NСН2), 3.37 s (2Н, SCН2), 3.77 t
(6Н, ОСН2), 7.11–7.70 m (5Н, Ind). 13C NMR spectrum
(D2O), δ, ppm: 50.91 (NCН2), 57.11 (SCH2), 57.37
(ОСН2), 105.88–138.96 (Ind), 177.27 (С=О). Found,
%: С 54.01, Н 6.77, N 7.80, S 9.09. Calculated for
С16Н24N2О5S (%): С 53.91, Н 6.78, N 7.86, S 8.99.
1b: yield 93%, colorless powder, mp 106°C, purity
99.7%. IR spectrum (KBr, ν, cm–1): 1700 (C=O), 3475
(ОН). 1H NMR spectrum (CD3OD), δ, ppm: 3.39 s (2Н,
SСН2), 3.72 s (3Н, N–Me), 7.15–7.75 m (5Н, Ind).
2b: yield 99%, colorless powder with mp 90°C,
purity 98.0%. IR spectrum (KBr, ν, cm–1): 1600 (С=О),
1
2720 (N + Н), 3310 (ОН). H NMR spectrum (D2O),
Found, %:
C 59.78, Н 4.99, N 6.37. Calculated for
δ, ppm: 3.20 t (6Н, NСН2), 3.30 s (2Н, SCН2), 3.70 s
(3Н, N–Me), 3.75 t (6Н, ОСН2), 7.12–7.75 m (5Н, Ind),
180.07 (С=О).
С11Н11NО2S, %: С 59.71, Н 5.01, N 6.33.
1c: yield 95%, colorless powder, mp 108°C, purity
99.7%. IR spectrum (KBr, ν, cm–1): 1701 (C=O), 3435
2c: yield 96%, colorless powder with mp 94°C,
purity 98.6%. IR spectrum (KBr, ν, cm–1): 1607 (С=О),
1
(ОН). H NMR spectrum (CD3OD), δ, ppm: 3.36 s
(2Н, SСН2), 5.23 s (2Н, NСН2), 7.06–7.72 m (10Н,
Bnz, Ind). 13C NMR spectrum (CD3OD), δ, ppm: 38.55
(SСН2), 102.86–137.29 (Bnz, Ind), 172.83 (С=О).
1
2750 (N + Н), 3300 (ОН). H NMR spectrum (D2O),
δ, ppm: 3.32 t (6Н, NСН2), 3.36 s (2Н, SСН2), 3.83 t
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 91 No. 3 2018

472
ADAMOVICH, MIRSKOVA
(6Н, ОСН2), 5.44 s (2Н, СН2–C6Н5), 7.23–7.98 m
(10Н, Bnz, Ind). 13C NMR spectrum (D2O), δ, ppm:
38.00 (SСН2), 49.43 (СН2–С6Н5), 54.73 (NСН2), 54.80
(ОСН2), 110.15–135.52 (Bnz, Ind), 179.17 (С=О).
Siberian Branch, Russian Academy of Sciences “Basic
Research and Breakthrough Technologies as the Basis
for the Leading Development of the Baikal Region and
of Its Interregional Connections.”
2d: yield 96%, colorless powder with mp 136°C,
purity 98.1%. IR spectrum (KBr, ν, cm–1): 1380 (SO2),
1598 (С=О), 2800 (N + Н), 3320 (ОН). H NMR
The study was financially supported by the Russian
Foundation for Basic Research and Irkutsk oblast
government (research project no. 17-43-380006).
1
spectrum (D2O), δ, ppm: 3.39 t (6Н, NСН2), 3.88 t (6Н,
ОСН2), 4.19 s (2Н, SО2СН2), 5.35 s (2Н, СН2–C6Н5),
7.12–7.88 m (10Н, Bnz, Ind). 13C NMR spectrum
(D2O), δ, ppm: 37.10 (SСН2), 48.07 (СН2–С6Н5), 55.03
(NСН2), 55.10 (ОСН2), 61.54 (SО2СН2), 110.13–
134.00 (Bnz, Ind), 176.88 (С=О).
REFERENCES
1. Adamovich, S.N., Kashik, T.V., Chipanina, N.N., et al.,
Russ. J. Appl. Chem., 2009, vol. 82, no. 5, pp. 862–865.
2. Mirskova, A.N., Adamovich, S.N., Mirskov, R.G., et al.,
Russ. Chem. Bull., 2014, vol. 63, no. 9, pp. 1869–1883.
CONCLUSIONS
3. Adamovich, S.N., Ushakov, I.A., and Vashchenko, A.V.,
Mendeleev Commun., 2017, vol. 27, pp. 89–91.
1-R-Indol-3-ylsulfanyl(sulfonyl)acetic acids and
their tris(2-hydroxyethyl)ammonium salts (protatranes),
difficultly accessible previously, were synthesized by a
new efficient method. These compounds are of interest
as pharmacologically active substances and precursors
of immunomodulating and immunosuppressive drugs.
4. Sharma, V., Kumar, P., and Pathak, D., J. Heterocycl.
Chem., 2010, vol. 47, pp. 491–496.
5. Levkovskaya, G.G. and Rudyakova, E.V., Russ. J. Org.
Chem., 2002, vol. 38, no. 11, pp. 1641–1646.
6. AldrichAdvancing Science: Handbook of Fine Chemicals,
2007–2008, Sigma–Aldrich (Canada), 2006, pp. 433,
1479, 2079, 2091.
ACKNOWLEDGMENTS
7. Allergologiya i immunologiya: natsional’noe rukovodstvo
(Allergology and Immunology: National Guide),
Khaitov, R.M. and Il’ina, N.I., Eds., Moscow: GEOTAR-
Media, 2009.
The main results were obtained using the equipment
of the Baikal Analytical Center for Shared Use, Siberian
Branch, Russian Academy of Sciences.
8. Kolesnikova, O.P., Kudaeva, O.T., Sukhenko, T.G., et al.,
The study was performed within the framework of
the Integration Program of the Irkutsk Scientific Center,
Russ. J. Exp. Clin. Pharmacol., 2006, vol. 69, pp. 47–50.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 91 No. 3 2018