Synthesis of new carbamate derivatives of indole and their modification

Article abstract of DOI:10.1134/S107042801007016X

Oximation of indoles having a methoxycarbonylamino group on C⁵ and an acyl group on C³ with hydroxylamine hydrochloride in the presence of pyridine gave the corresponding oximes. The reduction of the 3-C=O group with sodium tetrahydridoborate in the presence of sodium hydroxide was accompanied by removal of the methoxycarbonyl group at the pyrrole nitrogen atom with formation of racemic alcohols. 1,4-Addition of 1-(pyridin-3-yl)butane-1,3- dione to dimethyl 1,4-benzoquinone diimine N,N′-dicarboxylate in dioxane in the presence of sodium methoxide, followed by heating in boiling 22% hydrochloric acid, afforded methyl 2-methyl-5-(methoxycarbonylamino)-3-(pyridin- 3-ylcarbonyl)-1H-indole-1-carboxylate. 3-(Dimethylamino)-1-(4-methyl-1,2,5- oxadiazol-3-yl)prop-2-en-1-one reacted with N,N′-bis(methoxycarbonyl)- and N,N′-bis(phenylsulfonyl)-1,4-benzoquinone diimines in methylene chloride and acetic acid, respectively, in the presence of BF₃ ? Et ₂O to produce indoles having a 1,2,5-oxadiazolylcarbonyl group on C₃.

Full text of DOI:10.1134/S107042801007016X

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2010, Vol. 46, No. 7, pp. 1060–1065. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © A.V. Velikorodov, A.K. Kuanchalieva, O.L. Titova, 2010, published in Zhurnal Organicheskoi Khimii, 2010, Vol. 46, No. 7,
pp. 1061–1066.
Synthesis of New Carbamate Derivatives of Indole
and Their Modification
A. V. Velikorodov, A. K. Kuanchalieva, and O. L. Titova
Astrakhan State University, pl. Shaumyana 1, Astrakhan, 414000 Russia
e-mail: avelikorodov@mail.ru
Received June 5, 2009
Abstract—Oximation of indoles having a methoxycarbonylamino group on C5 and an acyl group on C3 with
hydroxylamine hydrochloride in the presence of pyridine gave the corresponding oximes. The reduction of the
3-C=O group with sodium tetrahydridoborate in the presence of sodium hydroxide was accompanied by
removal of the methoxycarbonyl group at the pyrrole nitrogen atom with formation of racemic alcohols.
1,4-Addition of 1-(pyridin-3-yl)butane-1,3-dione to dimethyl 1,4-benzoquinone diimine N,N′-dicarboxylate in
dioxane in the presence of sodium methoxide, followed by heating in boiling 22% hydrochloric acid, afforded
methyl 2-methyl-5-(methoxycarbonylamino)-3-(pyridin-3-ylcarbonyl)-1H-indole-1-carboxylate. 3-(Dimethyl-
amino)-1-(4-methyl-1,2,5-oxadiazol-3-yl)prop-2-en-1-one reacted with N,N′-bis(methoxycarbonyl)- and
N,N′-bis(phenylsulfonyl)-1,4-benzoquinone diimines in methylene chloride and acetic acid, respectively, in the
presence of BF3·Et2O to produce indoles having a 1,2,5-oxadiazolylcarbonyl group on C3.
DOI: 10.1134/S107042801007016X
One of the most fruitful and extensively developing
fields in the chemistry of heterocyclic compounds is
chemical modification of natural and synthetic biologi-
cally active substances. Nitrogen-containing hetero-
cycles are traditional compounds exhibiting various
kinds of biological activity.
polyfunctional compounds. The above stated deter-
mined perspectives in the corresponding modifications
of carbamate indole derivatives.
Indolyl ketones Ia and Ib were subjected to oxima-
tion by the action of hydroxylamine hydrochloride in
the systems NaOH–EtOH, AcONa–dioxane, and pyri-
dine–EtOH, as well as in the presence of pyridine [6].
The best results were obtained in pyridine on heating
at 50°C over a period of 1.5 h (Scheme 1). The IR
spectra of oximes IIa and IIb are hardly suitable for
identification of their structure, for stretching vibra-
tions of the C=N bond give rise to absorption in the
region 1640–1630 cm–1; analogous absorption band of
nonconjugated oximes is located at about 1640 cm–1.
The structure of compounds IIa and IIb was con-
We previously reported on the synthesis of indole
derivatives possessing a carbamate group on C5 [1–3].
However, poor solubility of these compounds is a con-
siderable drawback which reduces their pharmacologi-
cal value. Therefore, their modification with a view to
improve their solubility and introduce new pharmaco-
phoric groups seemed to be important. The presence of
a carbonyl group on C3 in indoles obtained by the
Michael reaction of N,N′-bis(methoxycarbonyl)-1,4-
benzoquinone diimine with β-diketones implies the
possibility for transformation of that group into oxime
or hydroxy. The oxime group in indole compounds is
responsible for their antiarrhythmic, hypotensive, anti-
depressant, psychotropic, antiphlogistic, and antiviral
activity [4]. Furthermore, oxime group may be reduced
to amino. Hydroxy group is a structural unit of a large
number of natural and synthetic biologically active
substances [5]. Nitro-substituted carbamate derivatives
of indole can find specific application, or they may be
used as intermediate products in the synthesis of other
1
firmed by their H and 13C NMR spectra. In the
1H NMR spectrum of oxime IIa we observed a double
set of signals belonging to protons in the methyl group
on C2 (δ 2.58 and 2.24 ppm for the syn and anti
isomers, respectively), methyl group in the oxime
residue (δsyn 2.25, δanti 2.16 ppm), and hydroxy group
(δsyn 10.32, δanti 9.69 ppm), indicating the presence of
two isomers (s-cis–trans or syn–anti isomerism). The
4-H proton resonates in a weaker field (δ 8.31 ppm)
relative to the corresponding signal of indole
(δ 8.25 ppm), so that we presumed conservation of the
1060

SYNTHESIS OF NEW CARBAMATE DERIVATIVES OF INDOLE
1061
Scheme 1.
O
HON
R'
R'
H
H
NH2OH·HCl
pyridine
MeO
N
MeO
N
R
R
O
O
N
N
OMe
OMe
O
O
Ia, Ib
IIa, IIb
R = R′ = Me (a); RR′ = CH2CMe2CH2 (b).
Scheme 2.
O
O
HO
R'
R'
H
H
N
MeO
N
MeO
NaBH4, EtOH–H2O
R
R
O
O
N
N
H
OMe
Ia–Ic
IIIa–IIIc
R = R′ = Me (a); RR′ = CH2CMe2CH2 (b); R = Me, R′ = Ph (c).
s-trans conformation and the presence of two forms
was ascribed to syn–anti isomerism [7].
δ 3.72–3.65 ppm; in addition, a signal from the hy-
droxy proton appeared in the region δ 5.90–3.55 ppm.
The 13C NMR spectrum of oxime IIb having fixed
s-trans conformation also contained signals from two
isomers which may differ only in the orientation of the
oxime hydroxy group. Here, γ-effect of the hydroxy
group is clearly observed: the difference in the chem-
ical shifts of the methylene and quaternary carbon
atoms is 14.80 and 3.30 ppm, respectively. This fact
also counts in favor of syn–anti isomerism of oxime
IIb. The predominant formation of oximes IIa and IIb
as syn-s-trans isomers may be rationalized in terms of
steric repulsion between the oxime OH group and
proton on C4 in the anti-s-trans isomer.
Indoles Ia and Ic were subjected to nitration ac-
cording to the procedure described in [9], i.e., using
copper(II) nitrate hexahydrate in a mixture of acetic
acid with acetic anhydride. The reaction mixtures were
heated for 1 h at 70°C. Analysis by thin-layer chroma-
1
tography and H NMR data showed that the nitration
was regioselective. The products were the correspond-
ing 4-nitro derivatives IVa and IVc (Scheme 3).
Isomeric 6-nitro derivatives should display in the
1H NMR spectra two singlets from aromatic protons on
C4 and C7. The spectra of the products contained two
doublets at δ 7.45–7.55 and 8.25–.38 ppm, indicating
formation of just 4-nitroindoles IVa and IVc.
We tried to reduce the carbonyl group in indoles
Ia–Ic to hydroxy with sodium tetrahydridoborate in
aqueous ethanol in the presence of sodium hydroxide
[8]. It was found that the reaction occurs fairly readily
at 60–70°C (in 1 h) and that it is accompanied by
reductive elimination of the methoxycarbonyl group at
the pyrrole nitrogen atom to give the corresponding
racemic alcohols IIIa–IIIc in good yields (Scheme 2).
The structure of compounds IIIa–IIIc was confirmed
Scheme 3.
O
NO2
R'
H
Cu(NO3)2 ·6H2O
MeO
N
AcOH–Ac2O, 70°C
Ia, Ic
R
O
N
OMe
O
IVa, IVc
1
1
by IR and H NMR spectra. The H NMR spectra of
IIIa–IIIc lacked singlets typical of the methoxycar-
bonyl group on the pyrrole nitrogen atom in the initial
indoles (δ 4.07–4.02 ppm), whereas signals from the
methoxycarbonylamino group on C5 were observed at
We also made an attempt to synthesize carbamate
indole derivatives possessing a pyridine fragment. For
this purpose, we examined the reaction of N,N′-bis-
(methoxycarbonyl)-1,4-benzoquinone diimine (V) with
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 7 2010

VELIKORODOV et al.
1062
Scheme 4.
NCOOMe
O
O
NHCOOMe
NHCOOMe
MeONa, dioxane
Me
O
+
N
NCOOMe
N
Me
O
V
VI
VII
O
H
N
MeO
N
(1) 22% HCl, Δ
(2) Aq. NH3
Me
O
N
OMe
O
VIII
[10–12]. We previously showed [13] that N,N′-bis-
(methoxycarbonyl)-1,4-benzoquinone diimine (V) is
capable of reacting with some enamino ketones. In
continuation of these studies we examined the react-
ions of 3-dimethylamino-1-(4-methyl-1,2,5-oxadiazol-
3-yl)prop-2-en-1-one (X) with compound V in meth-
ylene chloride and with N,N′-bis(phenylsulfonyl)-1,4-
benzoquinone diimine (IX) in acetic acid in the pres-
ence of BF3 ·Et2O. Unlike bis-sulfonamide IX, the
reaction of X with bis-carbamate V cannot be carried
out in acetic acid because of concurrent 1,4-addition of
acetic acid at the N=C–C=C conjugated bond system
with formation of the corresponding acetoxyphenol
[14]. By Neniţsescu reaction of compounds V and IX
with X we obtained indole derivatives XI and XII in
good yields (77–85%), and the product structure was
confirmed by IR, 1H NMR, and mass spectra.
1-(pyridin-3-yl)butane-1,3-dione (VI) in dioxane in the
presence of sodium methoxide. The reaction mixture
was kept for 8 h at 20°C, and the product was the
corresponding Michael adduct with aromatic structure.
The structure of dimethyl 2-[1,3-dioxo-1-(pyridin-3-
yl)butan-2-yl]-1,4-phenylenedicarbamate (VII) was
confirmed by IR spectroscopy. Treatment of compound
VII with boiling 22% hydrochloric acid over a period
of 2 h, followed by neutralization with 25% aqueous
ammonia gave substituted indole derivative VIII
1
(Scheme 4). The H NMR spectrum of methyl 5-(me-
thoxycarbonylamino)-2-methyl-3-(pyridin-3-ylcarbon-
yl)-1H-indole-1-carboxylate (VIII) contained singlets
from protons in the methyl group on C2, NHCO2Me
and NCO2Me groups, and 4-H at δ 2.64 (3H), 3.73
(3H), 3.96 (3H), and 8.48 ppm (1H), respectively, as
well as a multiplet at δ 8.08–8.19 ppm from the aro-
matic protons, a doublet from 4′-H at δ 8.58 ppm (J =
5.2 Hz), a singlet from 2′-H at δ 8.85 ppm, and a broad-
ened singlet from the NH proton at δ 8.65 ppm.
EXPERIMENTAL
1
The H NMR spectra were recorded on a Varian
VXR-400 spectrometer at 400.13 MHz using tetra-
Neniţsescu reaction provides one of the most im-
portant methods for the synthesis of 5-hydroxyindols
methylsilane as internal reference. The 13C NMR spec-
Scheme 5.
Me
NR
N
O
O
Me
O
BF3 ·Et2O
Me
H
N
+
N
N
N
O
R
N
Me
N
NR
R
V, IX
X
XI, XII
V, IX, R = CO2Me; XI, XII, R = SO2Ph.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 7 2010

SYNTHESIS OF NEW CARBAMATE DERIVATIVES OF INDOLE
1063
tra were obtained on a Bruker WM-400 instrument at
100 MHz with complete decoupling from protons. The
IR spectra were measured in the frequency range from
4000 to 400 cm–1 on IKS-29 and Infra-LUM FT-02
spectrometers from samples dispersed in mineral oil
(except for XI and XII). The mass spectra (electron
impact, 70 eV) were recorded on a Finnigan MAT
INCOS 50 instrument. The purity of the products was
checked by thin-layer chromatography on Silufol UV-
254 plates.
(NHCO2Me). Found, %: C 59.96; H 5.92; N 11.58.
C18H21N3O5. Calculated, %: C 60.17; H 5.85; N 11.70.
Methyl 3-(1-hydroxyethyl)-2-methyl-1H-indol-5-
ylcarbamate (IIIa). Several drops of a 10% aqueous
solution of sodium hydroxide was added to a mixture
of 12 ml of ethanol and 6 ml of water, 0.2 g
(5.4 mmol) of sodium tetrahydridoborate was added,
the mixture was heated to 60–70°C, and 1.1 g
(3.62 mmol) of compound Ia was added in portions
under stirring. The mixture was stirred for 1 h at that
temperature, diluted with water (30 ml), and extracted
with diethyl ether (3×25 ml), the extracts were com-
bined, washed with water (50 ml), dried over sodium
sulfate, and evaporated, and the residue was recrystal-
lized from ethyl acetate–petroleum ether (1 :3 by
volume). Yield 0.88 g (79%), colorless crystals,
mp 165–166°C. IR spectrum, ν, cm–1: 3470–3320 (NH,
OH); 1710 (C=O); 1620, 1595, 1555 (C=C, C=Carom).
1H NMR spectrum (acetone-d6), δ, ppm: 1.50 m (3H,
CHCH3), 2.75 s (3H, 2-CH3), 3.55 s (1H, OH), 3.71 s
(3H, NHCO2CH3), 4.63 m (1H, CHCH3), 6.05 br.s
(1H, NH), 7.30 d (1H, 6-H, J = 8.0 Hz), 7.42 d (1H,
7-H, J = 8.0 Hz), 7.92 s (1H, 4-H), 8.45 br.s (1H, NH).
Found, %: C 63.14; H 6.19; N 11.25. C13H16N2O3. Cal-
culated, %: C 62.90; H 6.45; N 11.29.
Initial indolylcarbamates Ia–Ic and bis-sulfonamide
IX were synthesized by known methods [1, 15].
Methyl 3-(1-hydroxyiminoethyl)-5-(methoxycar-
bonylamino)-2-methyl-1H-indole-1-carboxylate
(IIa). A mixture of 0.88 g (2.89 mmol) of methyl 3-
acetyl-5-(methoxycarbonylamino)-2-methyl-1H-in-
dole-1-carboxylate (Ia), 0.20 g (2.89 mmol) of hy-
droxylamine hydrochloride, and 5 ml of anhydrous
pyridine was heated for 1.5 h at 50°C (on a water
bath). The mixture was cooled and poured into ice
water, and the precipitate was filtered off, washed on
a filter with water (20 ml), dried in air, and recrystal-
lized from ethanol. Yield 0.59 g (64%), colorless crys-
tals, mp 178–179°C. IR spectrum, ν, cm–1: 3345 (NH,
OH); 1720 (C=O); 1630 (C=N); 1615, 1570, 1545
1
(C=C, C=Carom). H NMR spectrum (DMSO-d6), δ,
Methyl 4-hydroxy-2,2-dimethyl-2,3,4,9-tetrahy-
dro-1H-carbazol-6-ylcarbamate (IIIb) was synthe-
sized in a similar way by reduction of 1 g (2.9 mmol)
of compound Ib with 0.17 g (4.33 mmol) of sodium
tetrahydridoborate. The product was extracted into
methylene chloride (3 ×20 ml). Yield 0.8 g (82%),
colorless crystals, mp 266–268°C (from chloroform).
IR spectrum, ν, cm–1: 3375–3300 (NH, OH); 1710
ppm: 2.16 s and 2.25 s (3H, MeC=N), 2.28 s and
2.58 s (3H, 2-Me), 3.74 s (3H, NHCO2Me), 3.98 s
(3H, NCO2Me), 7.64 d (7-H, J = 8.0 Hz), 8.01 d (6-H,
J = 8.0 Hz), 8.31 s (4-H), 8.54 br.s (1H, NH), 9.69 s
and 10.32 s (1H, OH). Found, %: C 56.11; H 4.99;
N 13.02. C15H17N3O5. Calculated, %: C 56.43; H 5.33;
N 13.17.
1
(C=O); 1635, 1575, 1545 (C=C, C=Carom). H NMR
Methyl 4-hydroxyimino-6-(methoxycarbonyl-
amino)-2,2-dimethyl-1,2,3,4-tetrahydro-9H-carba-
zole-9-carboxylate (IIb) was synthesized in a similar
way by reaction of 0.5 g (1.45 mmol) of tetrahydrocar-
bazole Ib and 0.1 g (1.45 mmol) of hydroxylamine
hydrochloride. Yield 0.37 g (71%), Colorless crystals,
mp 202–203°C (from EtOH). IR spectrum, ν, cm–1:
3360 (NH, OH); 1725 (C=O); 1640 (C=N); 1615, 1595,
1540 (C=C, C=Carom). 13C NMR spectrum (acetone-d6),
δC, ppm: 29.50 and 30.72 (Me), 35.01 and 35.25 (C11),
37.14 and 37.23 (C10), 39.51 and 42.81 (C12, ΔδC =
3.30), 52.75 (NHCO2CH3), 53.42 (NCO2CH3), 108.41
and 123.21 (C3, ΔδC = 14.80), 115.23 and 116.01 (C7),
118.51 and 119.02 (C6), 120.15 and 120.21 (C4),
125.65 and 126.07 (C8), 131.62 and 131.65 (C9),
131.72 and 132.58 (C5), 145.14 and 145.27 (C2),
146.65 and 147.55 (C13), 149.01 (NCO2Me), 153.43
spectrum (DMSO-d6), δ, ppm: 1.05 s (6H, Me), 2.30 s
(2H, CH2), 2.82 s (2H, CH2), 3.65 s (4H, NHCO2CH3,
OH), 5.50 t (1H, CHOH, J = 2.3 Hz), 5.75 s (1H, NH),
7.25 q (2H, Harom, J = 7.1 Hz), 8.05 s (1H, 4-H),
9.35 br.s (1H, NH). Found, %: C 66.50; H 7.03; N 9.41.
C16H20N2O3. Calculated, %: C 66.67; H 6.94; N 9.72.
Methyl 3-[hydroxy(phenyl)methyl]-2-methyl-
1H-indol-5-ylcarbamate (IIIc) was synthesized in
a similar way by reduction of 1.32 g (3.61 mmol) of
indole Ic with 0.2 g (5.4 mmol) of sodium tetra-
hydridoborate. Yield 0.96 g (71%), colorless crystals,
mp 130–133°C (from ethyl acetate–petroleum ether,
1 :3 by volume). IR spectrum, ν, cm–1: 3410–3300
(NH, OH); 1715 (C=O); 1635, 1600, 1555 (C=C,
1
C=Carom). H NMR spectrum (CDCl3), δ, ppm: 2.20 s
(3H, Me), 3.50 d (1H, OH), 3.72 s (3H, NHCO2CH3),
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 7 2010

VELIKORODOV et al.
1064
5.90 s (1H, CHOH), 6.25 br.s (1H, NH), 7.00–7.25 m
(5H, Harom), 7.30 d (1H, 6-H, J = 8.0 Hz), 7.48 d (1H,
7-H, J = 8.0 Hz), 7.72 s (1H, 4-H), 8.45 br.s (1H, NH).
Found, %: C 69.41; H 5.58; N 9.17. C18H18N2O3. Cal-
culated, %: C 69.68; H 5.81; N 9.03.
crystals, mp 159–160°C. IR spectrum, ν, cm–1: 3340
(NH); 1725, 1670 (C=O); 1620, 1570, 1550 (C=C,
C=Carom). Found, %: C 58.98; H 4.72; N 10.81.
C19H19N3O6. Calculated, %: C 59.22; H 4.94; N 10.91.
Methyl 5-(methoxycarbonylamino)-2-methyl-3-
(pyridin-3-ylcarbonyl)-1H-indole-1-carboxylate
(VIII). A mixture of 1 g of compound VII and 10 ml
of 22% hydrochloric acid was heated for 3 h at the
boiling point. The mixture was cooled, 25% aqueous
ammonia was added dropwise until neutral reaction,
and the precipitate was filtered off, washed on a filter
with water, dried in air, and recrystallized from etha-
nol. Yield 0.9 g (94%), colorless crystals, mp 185–
187°C. IR spectrum, ν, cm–1: 3330 (NH); 1715 (C=O);
Methyl 3-acetyl-5-(methoxycarbonylamino)-
2-methyl-4-nitro-1H-indole-1-carboxylate (IVa).
A mixture of 1.7 g (5.59 mmol) of indole Ia, 0.99 g
(3.35 mmol) of copper(II) nitrate hexahydrate, 10 ml
of glacial acetic acid, and 3 ml of acetic anhydride was
heated for 1 h at 70°C. The mixture was cooled and
poured into 100 ml of ice water, and the precipitate
was filtered off, washed on a filter with water (50 ml),
dried in air, and recrystallized from glacial acetic acid.
Yield 1.3 g (58%), light yellow crystals, mp 173–
175°C. IR spectrum, ν, cm–1: 3360 (NH); 1760, 1690
(C=O); 1620, 1590, 1550 (C=C, C=Carom); 1520, 1330
1
1635, 1600, 1555 (C=C, C=Carom). H NMR spectrum
(DMSO-d6), δ, ppm: 2.64 s (3H, Me), 3.73 s (3H,
NHCO2CH3), 3.96 s (3H, NCO2CH3), 8.08–8.19 m
(4H, Harom), 8.48 s (1H, 4-H), 8.58 d (1H, 4′-H, J =
5.2 Hz), 8.65 br.s (1H, NH), 8.85 s (1H, 2′-H). Found,
%: C 62.24; H 4.36; N 11.14. C19H17N3O5. Calculated,
%: C 62.13; H 4.63; N 11.44.
1
(NO2). H NMR spectrum (DMSO-d6), δ, ppm: 2.35 s
(3H, COMe), 3.02 s (3H, 2-Me), 3.75 s (3H,
NHCO2CH3), 4.10 s (3H, NCO2CH3), 7.55 d (1H, 7-H,
J = 10.0 Hz), 8.25 d (1H, 6-H, J = 10.0 Hz), 9.20 br.s
(1H, NH). Found, %: C 51.22; H 3.98; N 12.31.
C15H15N3O7. Calculated, %: C 51.58; H 4.30; N 12.03.
Methyl 5-(methoxycarbonylamino)-3-(4-methyl-
1,2,5-oxadiazol-3-ylcarbonyl)-1H-indole-1-carbox-
ylate (XI). Compound V, 0.6 g (2.7 mmol), was dis-
solved in 10 ml of methylene chloride, 0.5 g
(2.7 mmol) of 3-dimethylamino-1-(4-methyl-1,2,5-
oxadiazol-3-yl)prop-2-en-1-one (X) and two drops of
boron trifluoride–ether complex were added, and the
mixture was kept for 30 min at room temperature. The
crystalline solid was filtered off, washed on a filter
with diethyl ether (10 ml), and recrystallized from
glacial acetic acid. Yield 0.74 g (77%), colorless crys-
tals, mp 233–235°C. IR spectrum (KBr), ν, cm–1: 3360
(NH); 3168, 3135, 2961 (C–Haliph); 1733 (C=O); 1595,
Methyl 3-benzoyl-5-(methoxycarbonylamino)-2-
methyl-4-nitro-1H-indole-1-carboxylate (IVc) was
synthesized in a similar way by reaction of 2 g
(5.59 mmol) of indole Ic with 0.99 g (3.35 mmol) of
copper(II) nitrate hexahydrate. Yield 1.35 g (60%),
yellow crystals, mp 214–215°C (from glacial acetic
acid). IR spectrum, ν, cm–1: 3360 (NH); 1770, 1670
(C=O); 1620, 1570, 1550 (C=C, C=Carom); 1510, 1350
1
(NO2). H NMR spectrum (DMSO-d6), δ, ppm: 2.43 s
(3H, Me), 3.70 s (3H, NHCO2CH3), 4.10 s (3H,
NCO2CH3), 7.45 t (2H, Harom, J = 6.0 Hz), 7.60 t (1H,
1
H
arom, J = 6.0 Hz), 7.75 d (3H, Harom, J = 8.5 Hz),
1541, 1487 (C=C, C=Carom). H NMR spectrum
8.38 d (1H, Harom, J = 8.5 Hz), 9.10 br.s (1H, NH).
Found, %: C 58.51; H 4.02; N 10.56. C20H17N3O7. Cal-
culated, %: C 58.39; H 4.14; N 10.22.
(DMSO-d6), δ, ppm: 2.50 s (3H, Me), 3.71 s (3H,
NHCO2CH3), 4.07 s (3H, NCO2CH3), 7.55 d.d (1H,
6-H, J = 2.1, 9.0 Hz), 8.06 d (1H, 7-H, J = 9.0 Hz),
8.57 s (1H, 2-H), 8.72 s (1H, 4-H), 9.76 br.s (1H, NH).
Mass spectrum, m/z (Irel, %): 359 [M + 1]+ (23), 358
[M]+ (100), 326 (7.7), 317 (11), 275 (69), 268
(38.5), 243 (23.1), 216 (38.5), 199 (46.2), 184 (38.4),
171 (30.8), 157 (61.5), 143 15.4), 129 (23.1), 116
(12.3), 102 (21.5), 79 (12.3). Found, %: C 53.38;
H 4.02; N 15.45. C16H14N4O6. Calculated, %: C 53.63;
H 3.91; N 15.64.
Dimethyl {2-[1,3-dioxo-1-(pyridin-3-yl)butan-2-
yl]benzene-1,4-diyl}biscarbamate (VII). Dimethyl
cyclohexa-2,5-diene-1,4-diylidenebiscarbamate (V),
0.99 g (4.5 mmol), was dissolved in 10 ml of anhy-
drous dioxane, 0.75 g (4.6 mmol) of 1-(pyridin-3-yl)-
butane-1,3-dione (VI) and 0.04 g of sodium methoxide
were added, and the mixture was kept for 8 h (until
complete conversion of V). The mixture was poured
into 50 ml of ice water, 2 drops of glacial acetic acid
were added, and the precipitate was filtered off, dried
in air, and recrystallized from chloroform–petroleum
ether (1:2 by volume). Yield 1.4 g (84%), colorless
N-[3-(4-Methyl-1,2,5-oxadiazol-3-ylcarbonyl)-1-
phenylsulfonyl-1H-indol-5-yl]benzenesulfonamide
(XII). p-Quinone diimine IX, 1.0 g (2.59 mmol), was
dissolved in 10 ml of glacial acetic acid, 0.5 g
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 46 No. 7 2010

SYNTHESIS OF NEW CARBAMATE DERIVATIVES OF INDOLE
1065
5. Ishizuka, T., Ishibuchi, S., and Kunieda, T., Tetrahedron,
(2.59 mmol) of compound X and two drops of boron
trifluoride–ether complex were added, and the mixture
was stirred for 10 h and poured into ice water (100 ml).
The precipitate was filtered off, dried in air, and re-
crystallized from dioxane. Yield 1.15 g (85%), color-
less crystals, mp 256–258°C. IR spectrum (KBr), ν,
cm–1: 3246 (NH); 3142 (C–Haliph); 1651 (C=O); 1618,
1600, 1531 (C=C, C=Carom); 1335, 1159 (SO2).
1H NMR spectrum (DMSO-d6), δ, ppm: 2.50 s (3H,
Me), 7.25 d (1H, Harom, J = Hz), 7.47–7.53 m (3H,
1993, vol. 49, p. 1841.
6. Weygand–Hilgetag Organisch-chemische Experimen-
tierkunst, Hilgetag, G. and Martini, A., Eds., Leipzig:
Johann Ambrosius Barth, 1964, 3rd ed. Translated under
the title Metody eksperimenta v organicheskoi khimii,
Moscow: Khimiya, 1968, p. 944.
7. Yurovskaya, M.A., Druzhinina, V.V., Tyurekhodzhae-
va, M.A., Shestakova, A.K., Chertkov, V.A., and
Bundel’, Yu.G., Khim. Geterotsikl. Soedin., 1984, p. 65.
8. Repinskaya, I.B. and Shvartsberg, M.S., Izbrannye
metody sinteza organicheskikh soedinenii (Selected
Methods of Synthesis of Organic Compounds), Novo-
sibirsk: Novosib. Gos. Univ., 2000, p. 284.
H
arom, 2-H), 7.55–7.57 m (1H, Harom), 7.63 t (2H, Harom
J = 8.3 Hz), 7.72–7.80 m (3H, Harom), 7.93 d (1H,
arom, J = 9.0 Hz), 8.14 d (2H, Harom, J = 9.0 Hz),
,
H
8.81 s (1H, Harom), 10.45 br.s (1H, NH). Mass spec-
trum, m/z (Irel, %): 522 [M]+ (2.6), 381 (46), 157 (77),
141 (100), 77 (98). Found, %: C 54.83; H 3.22;
N 10.56. C24H18N4O6S2. Calculated, %: C 55.11;
H 3.44; N 10.72.
9. Vatsuro, K.V. and Mishchenko, G.L., Imennye reaktsii v
organicheskoi khimii (Name Reactions in Organic
Chemistry), Moscow: Khimiya, 1976, p. 528.
10. Ketcha, D.M., Wilson, L.J., and Portlock, D.E., Tetra-
hedron Lett., 2000, vol. 41, p. 6253.
11. Lyubchanskaya, V.M., Alekseeva, L.M., and Gra-
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