1,7-dithioxo systems. Reaction of 3-[(5,5-dimethyl-3-thioxocyclohex-1-en-1yl)sulfanyl]-5,5-dimethylcyclohex-2-ene-1-thione with 2-aminoethanol and ethane-1,2-diamine

Article abstract of DOI:10.1134/S1070428009120082

The reaction of 3-[(5,5-dimethyl-3-thioxocyclohex-1-en-1-yl)sulfanyl]-5,5-dimethylcyclohex-2-ene-1-thione with 2-aminoethanol involves cleavage of the sulfide bond with formation of 3-[(2-hydroxyethyl)-amino]-5,5-dimethylcyclohex-2-ene-1-thione as the maj

Full text of DOI:10.1134/S1070428009120082

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2009, Vol. 45, No. 12, pp. 1795–1798. © Pleiades Publishing, Ltd., 2009.
Original Russian Text © L.V. Timokhina, L.V. Kanitskaya, 2009, published in Zhurnal Organicheskoi Khimii, 2009, Vol. 45, No. 12, pp. 1800–1803.
1,7-Dithioxo Systems. Reaction of 3-[(5,5-Dimethyl-3-thioxo-
cyclohex-1-en-1yl)sulfanyl]-5,5-dimethylcyclohex-2-ene-1-thione
with 2-Aminoethanol and Ethane-1,2-diamine
L. V. Timokhina and L. V. Kanitskaya
Favorskii Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences,
ul. Favorskogo 1, Irkutsk, 664033 Russia
e-mail: tim@irioch.irk.ru
Received April 6, 2009
Abstract—The reaction of 3-[(5,5-dimethyl-3-thioxocyclohex-1-en-1-yl)sulfanyl]-5,5-dimethylcyclohex-2-
ene-1-thione with 2-aminoethanol involves cleavage of the sulfide bond with formation of 3-[(2-hydroxyethyl)-
amino]-5,5-dimethylcyclohex-2-ene-1-thione as the major product. The reaction of the same sulfide with
ethane-1,2-diamine gave previously unknown 3-({2-[(5,5-dimethyl-3-thioxocyclohex-1-en-1-yl)amino]ethyl}-
amino)-5,5-dimethylcyclohex-2-ene-1-thione.
DOI: 10.1134/S1070428009120082
In continuation of our studies on the chemical prop-
erties of compounds containing an S=CC=CSC=CC=S
fragment [1, 2], in the present work we examined
reactions of 3-[(5,5-dimethyl-3-thioxocyclohex-1-en-
1-yl)sulfanyl]-5,5-dimethylcyclohex-2-ene-1-thione (I)
with N,O- and N,N-binucleophiles. The reactions of
dithioxo sulfide I with 2-aminoethanol and ethane-1,2-
diamine were carried out in acetonitrile in an inert
atmosphere. Like aminolysis of compound I reported
previously [2], these reactions involved cleavage of the
sulfide bond in the substrate.
3-methoxy-5,5-dimethylcyclohex-2-ene-1-thione [3].
In the present article we report for the first time de-
tailed spectral parameters of compound II. Its 1H NMR
spectrum contained signals at δ 6.49 ppm typical of
=CH protons and NH signal at δ 8.08 ppm; protons of
the methylene groups in the CH2CH2OH fragment
resonated at δ 3.39 and 4.74 ppm, respectively, and
broadened signal at δ 4.84 ppm was assigned to the
13
hydroxy proton. In the C NMR spectrum of II, the
CH2OH signal was located at δC 58.62 ppm, and the
=C–N carbon atom gave a signal at δC 161.48 ppm.
1
The reaction of I with 2-aminoethanol resulted in
the formation of 3-[(2-hydroxyethyl)amino]-5,5-di-
methylcyclohex-2-ene-1-thione (II) as the major prod-
uct (Scheme 1). Enamino thioketone II was synthe-
sized previously by reaction of 2-aminoethanol with
Analysis of the H ans 13C NMR spectra showed
that the reaction of dithioxo sulfide (I) with 2-amino-
ethanol at 20°C, apart from enamino thioketone II,
produced a small amount of 3-[(2-{2-[(5,5-dimethyl-3-
thioxocyclohex-1-en-1-yl)amino]ethoxy}ethyl)amino]-
5,5-dimethylcyclohex-2-ene-1-thione (III).
Scheme 1.
Me
Me
Me
Me
Me
Me
Me
Me
+
2H2NCH2CH2OH
O
S
N
N
S
S
S
S
H
H
I
III
The minor product displayed in the 13C NMR spec-
trum nine signals whose position was similar to the
position of signals in the spectrum of II. In particular,
signals at δC 166.34 (=C–N), 114.22 (=CH), and
59.94 ppm (CH2OCH2) were present. In addition, the
Me
Me
2
+ H2S
S
NHCH2CH2OH
II
1795

TIMOKHINA, KANITSKAYA
1796
1H NMR spectrum contained signals at δ 8.51 and
6.64 ppm, typical of NH and =CH protons, respec-
tively, while no signal assignable to hydroxy proton
was present. The molar ratio of compounds II and III,
calculated from signal intensities in the 1H NMR spec-
trum, was 1.00:0.09. An indirect support to the as-
sumed structure of III may be elemental composition
of the product mixture, calculated on the basis of the
1H NMR data, which coincided with the results of
chemical analysis (see Experimental).
The 13C NMR spectrum of the product mixture also
contained signals with lower intensity at δC 195.26,
166.33, 115.29, 57.16, 55.30, and 45.16 ppm; taking
1
into account the corresponding signals in the H NMR
spectrum, we identified the third product as 3-[(2-hy-
droxyethyl)amino]-5,5-dimethylcyclohex-2-en-1-one
(V). According to the signal intensity ratio in the
1H NMR spectrum, the molar ratio of compounds II,
IV, and V was estimated at 1.00:0.57:0.11. The ele-
mental composition calculated for that mixture was
consistent with that found experimentally.
When the reaction of dithioxo sulfide I with
2-aminoethanol was carried out at reduced temperature
(–10 to 0°C) in a more concentrated solution (2 mmol
of I in 10 ml of acetonitrile against 0.65 mmol in 30 ml
of acetonitrile in the reaction performed at 20°C), the
products were enamino thioketone II and previously
unknown 6,6-dimethyl-3,4,5,6,7,8-hexahydro-2H-1,4-
By reaction of dithioxo sulfide I with ethane-1,2-
diamine in acetonitrile at –10 to 0°C under argon we
obtained a new dithiocarbonyl compound, 3-({2-[(5,5-
dimethyl-3-thioxocyclohex-1-en-1-yl)amino]ethyl}-
amino)-5,5-dimethylcyclohex-2-ene-1-thione (VI)
(Scheme 2).
1
benzoxazine-8-thione (IV). The H NMR spectrum of
Scheme 2.
the product mixture contained minor signals indicating
the presence of a compound structurally related to II
but lacking hydroxy proton and proton at double C=C
I
+
H2NCH2CH2NH2
Me
S
Me
H
13
N
bond. Unlike thioketone II, in the C NMR spectrum
of the other product we observed signals at δC 138.95
and 159.73 ppm, whereas the C=S signal was dis-
placed appreciably upfield (ΔδC ~10 ppm). These find-
ings suggest the presence of a CH2OC=CN fragment
which could be formed via intramolecular cyclization
of enamino thioketone II at position 2 of the cyclo-
hexene ring (structure IV). The presence of a vinyl
ether fragment (C–O–C=C) in molecule IV should led
to considerable electron density redistribution over
the cyclohexene ring, i.e., delocalization over the
S=CC=CN bond system. As a result, the carbon atom
in the thiocarbonyl group in IV should be shielded to
a greater extent as compared to compound II, and the
C8a atom should be shielded more strongly than quater-
nary Cα atom in O–Cα=Cβ fragment; the chemical
shifts of the latter generally range from δC 145 to
152 ppm provided that there are no conjugated bonds
[4]. In addition, the C4a atom in molecule IV resonates
in a stronger field than does analogous carbon atom in
II, though the corresponding ΔδC value is smaller than
that observed for C=S.
N
H
Me
S
Me
VI
Its structure was determined on the basis of the IR
and NMR spectra and elemental analysis. In the IR
spectrum of dithione VI, stretching vibrations of the
C=S groups gave rise to a strong absorption band at
1050 cm–1, and vibrations the C=C bonds were charac-
terized by a frequency of 1525 cm–1. The NH absorp-
tion band was located at 3201 cm–1. The H NMR
1
spectrum of VI contained signals from methylene
protons in the NCH2CH2N fragment (δ 3.82 ppm),
the NH signal appeared as a broadened singlet at
δ 7.84 ppm, and olefinic protons resonated at
13
δ 6.29 ppm. In the C NMR spectrum of VI we ob-
served characteristic signals from carbon atoms in the
C=S (δC 217.67 ppm), =C–NH (δC 161.54 ppm), and
=CH fragments (δC 110.81 ppm).
EXPERIMENTAL
The IR spectra were recorded in KBr on an IFS 25
H
N
4
Me
Me
Me
Me
1
spectrometer. The H and 13C NMR spectra were
4a
8a
5
8
3
2
6
7
measured on a Bruker DPX-400 instrument at 400.1
and 100.4 MHz, respectively, using hexamethyldisilox-
ane as internal reference. The progress of reactions and
the purity of products were monitored by TLC on
1
O
O
NHCH2CH2OH
S
IV
V
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 45 No. 12 2009

1,7-DITHIOXO SYSTEMS. REACTION OF 3-[(5,5-DIMETHYL-3-THIOXO-...
1797
Silufol UV-254 plates using chloroform–ethyl acetate
(3:1) as eluent.
changed from dark green to dark orange). The mixture
was then kept for 20 h at 5°C, and the precipitate was
filtered off, washed with acetonitrile, and dried under
reduced pressure. We thus isolated 0.57 g of a mixture
of 3-[(2-hydroxyethyl)amino]-5,5-dimethylcyclohex-2-
ene-1-thione (II), 6,6-dimethyl-3,4,5,6,7,8-hexahydro-
2H-1,4-benzoxazine-8-thione (IV), and 3-[(2-hydroxy-
ethyl)amino]-5,5-dimethylcyclohex-2-en-1-one (V) as
yellow powder. IR spectrum, ν, cm–1: 3218, 3143,
3057 (NH); 1586, 1546 (C=C); 1048, 1025 (C=S).
1H NMR spectrum (CD3OD), δ, ppm: compound IV:
0.97 s (6H, CH3), 2.52 br.s (4H, 5-H, 7-H), 3.04 t (2H,
3-H, 3JHH = 5.12 Hz), 3.75 t (2H, 2-H, 3JHH = 5.12 Hz),
7.35 s (1H, NH); compound V: 1.05 s (6H, CH3),
2.44 s (2H, 4-H), 2.59 s (2H, 6-H), 3.46 t (2H, NCH2,
3-[(5,5-Dimethyl-3-thioxocyclohex-1-en-1-yl)sul-
fanyl]-5,5-dimethylcyclohex-2-ene-1-thione (I) was
synthesized according to the procedure reported in [5].
Reaction of dithioxo sulfide I with 2-amino-
ethanol. a. A solution of 0.079 g (1.3 mmol) of
2-aminoethanol in 3 ml of acetonitrile was added
dropwise over a period of 10 min to a solution of 0.2 g
(0.65 mmol) of compound I in 30 ml of anhydrous
acetonitrile under stirring in an argon atmosphere. The
color of the mixture changed from dark green to dark
orange, and vigorous evolution of hydrogen sulfide
was observed [test with a solution of Pb(OAc)2]. The
mixture was stirred for 12 h while continuously bub-
bling argon until hydrogen sulfide no longer evolved,
evaporated to 1/3 of the initial volume, and left over-
night at 5°C. The precipitate was filtered off, washed
with acetonitrile, and dried under reduced pressure. We
isolated 0.15 g of a mixture of 3-[(2-hydroxyethyl)-
amino]-5,5-dimethylcyclohex-2-ene-1-thione (II) and
3-[(2-{2-[(5,5-dimethyl-3-thioxocyclohex-1-en-1-yl)-
amino]ethoxy}ethyl)amino]-5,5-dimethylcyclohex-2-
ene-1-thione (III) as orange powder. IR spectrum, ν,
cm–1: 3217, 3057 (NH); 1585, 1545 (C=C); 1048
3
3JHH = 5.00 Hz), 3.69 t (2H, OCH2, JHH = 5.00 Hz),
8.99 s (1H, 2-H). 13C NMR spectrum (CD3OD), δC,
ppm: compound IV: 26.74 (CH3), 33.92 (C6), 41.54
(C5), 56.44 (C7), 57.61 (C2), 138.95 (C8a), 159.73 (C4a),
205.05 (C=S); compound V: 27.87 (CH3), 45.16
(NCH2), 55.30 (C6), 57.16 (CH2O), 115.29 (C2),
166.33 (C3), 195.26 (C=O). Found, %: C 63.18;
H 9.00; N 6.19; S 13.87. C10H17NOS (II), C10H15NS
(IV), C10H17NO (V). Calculated, %: C 60.83; H 8.27;
N 7.10; S 15.16 (according to the product ratio deter-
mined on the basis of the 1H and 13C NMR data).
1
(C=S). H NMR spectrum, δ, ppm: compound II (in
3-({2-[(5,5-Dimethyl-3-thioxocyclohex-1-en-1-yl)-
amino]ethyl}amino)-5,5-dimethylcyclohex-2-ene-1-
thione (VI). The reaction was carried out as described
above in b using 0.31 g (1 mmol) of compound I in
10 ml of anhydrous acetonitrile and 0.12 g (2 mmol) of
ethane-1,2-diamine in 4 ml of acetonitrile. Yield 0.23 g
(68%), yellow powder, mp 194–196°C. IR spectrum, ν,
CD3OD): 1.02 s (6H, CH3), 2.32 s (2H, 4-H), 2.65 s
(2H, 6-H), 3.39 t (2H, NCH2, 3J = 5.64 Hz), 4.74 t (2H,
3
OCH2, J = 5.64 Hz), 6.49 s (1H, 2-H), 8.08 br.s (in
DMSO-d6; 1H, NH); compound III (in DMSO-d6):
0.92 s (12H, CH3), 2.32 s and 2.49 s (4H each, 4-H,
6-H), 3.22 t (4H, OCH2), 3.27 t (4H, NCH2), 8.51 br.s
(2H, NH), 6.64 s (2H, 2-H). 13C NMR spectrum
(DMSO-d6), δC, ppm: compound II: 27.30 (CH3),
32.98 (C5), 42.03 (C4), 45.28 (NCH2), 51.12 (C6),
58.62 (CH2O), 110.00 (C2), 161.48 (C3), 215.12 (C=S);
compound III: 27.64 (CH3), 32.62 (C5), 41.04 (C4, C6),
45.11 (NCH2), 56.53 (C4, C6), 59.94 (CH2O), 114.22
(C2), 166.34 (C1, C3), 210.02 (C=S). Found, %:
C 59.40; H 8.68; N 7.30; S 16.98. C10H17NOS (II),
C20H32N2OS2 (III). Calculated, %: C 60.73; H 8.52;
N 7.09; S 16.19 (according to the product ratio deter-
mined on the basis of the 1H NMR data).
1
cm–1: 3201 (NH), 1525 (C=C), 1050 (C=S). H NMR
spectrum (DMSO-d6), δ, ppm: 0.94 s (12H, CH3),
2.19 s and 3.18 s (4H each, 4-H, 6-H), 3.82 br.s
(4H, NCH2), 6.29 s (2H, 2-H), 7.84 br.s (2H, NH).
13C NMR spectrum (DMSO-d6), δC, ppm: 27.82 (CH3),
33.25 (C5), 41.69 (C4, C6), 42.91 (NCH2), 58.00
(C4, C6), 110.81 (C2), 161.54 (C1, C3), 217.67 (C=S).
Found, %: C 63.50; H 8.37; N 8.09; S 18.84.
C18H18N2S2. Calculated, %: C 64.29; H 8.33; N 8.33;
S 19.05.
b. A suspension of 0.62 g (2 mmol) of dithioxo
sulfide I in 10 ml of anhydrous acetonitrile was cooled
to –14°C, a solution of 0.24 g (4 mmol) of 2-amino-
ethanol in 5 ml of acetonitrile was added dropwise
under stirring over a period of 20 min in an argon
atmosphere, and the mixture was stirred for 2 h at
–10 to 0°C (hydrogen sulfide evolved, and the mixture
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