Heterocyclization of N-hetaryl-N′-(prop-2-en-1-yl)thioureas by the action of sulfuryl chloride

Article abstract of DOI:10.1134/S1070428007070159

Cyclization of N-hetaryl-N′-(prop-2-en-1-yl)thioureas by the action of sulfuryl chloride leads to the formation of the corresponding 2-hetarylimino-5-chloromethylthiazolidine hydrochlorides which are converted into the free bases by treatment with aqueous

Full text of DOI:10.1134/S1070428007070159

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2007, Vol. 43, No. 7, pp. 1030–1034. © Pleiades Publishing, Ltd., 2007.
Original Russian Text © Yu.L. Zborovskii, V.V. Orysyk, V.I. Staninets, E.B. Rusanov, A.N. Chernega, 2007, published in Zhurnal Organicheskoi Khimii,
2007, Vol. 43, No. 7, pp. 1036–1040.
Heterocyclization of N-Hetaryl-N′-(prop-2-en-1-yl)thioureas
by the Action of Sulfuryl Chloride
Yu. L. Zborovskii, V. V. Orysyk, V. I. Staninets, E. B. Rusanov, and A. N. Chernega
Institute of Organic Chemistry, National Academy of Sciences of Ukraine,
ul. Murmanskaya 5, Kiev, 02660 Ukraine
e-mail: zborovsky@bpci.kiev.ua
Received December 6, 2006
Abstract—Cyclization of N-hetaryl-N′-(prop-2-en-1-yl)thioureas by the action of sulfuryl chloride leads to the
formation of the corresponding 2-hetarylimino-5-chloromethylthiazolidine hydrochlorides which are converted
into the free bases by treatment with aqueous sodium sulfite.
DOI: 10.1134/S1070428007070159
Halocyclization of functionally substituted ethyl-
enes and acetylenes underlies an important method for
the synthesis of nitrogen-, oxygen-, and sulfur-contain-
ing heterocycles [1]. The cyclizations are usually per-
formed using iodine or bromine as reagents. Highly
reactive chlorine promotes formation of a number of
by-products; therefore, it is not generally used in such
syntheses.
en-1-yl)thiourea (I) reacts with SO2Cl2 in chloroform
at room temperature (18–25°C) to give 5-(chloro-
methyl)-2-(pyridin-2-ylimino)-1,3-thiazolidine hydro-
chloride (II) in almost quantitative yield. Treatment of
the latter with an aqueous solution of sodium sulfite
afforded the corresponding free base III (Scheme 1).
Under analogous conditions, reactions of N-(1,3-
thiazol-2-yl)-N′-(prop-2-en-1-yl)thioureas IV and V
with an equimolar amount of SO2Cl2 lead to the forma-
tion of 5-chloromethylthiazolidine hydrochlorides VIa
and VIIa, respectively, in high yield (Scheme 2). In the
We were the first to use sulfuryl chloride as reagent
to effect halocyclization of N-hetaryl-N′-(prop-2-en-1-
yl)thiourea. We found that N-(pyridin-2-yl)-N′-(prop-2-
Scheme 1.
S
SO2Cl2
HN
Na2SO3
HN
·HCl
CH2Cl
CH2Cl
CH2
S
S
N
N
N
N
N
N
N
H
H
I
II
III
Scheme 2.
R'
S
S
SO2Cl2
S
N
HN
S
·HCl
R
R
CH2Cl
CH2
N
N
N
H
N
H
IV, V
VIa, VIb, VIIa, VIIb
R'
Na2SO3
S
HN
R
CH2Cl
N
S
N
VIIIa, VIIIb, IXa, IXb
IV, VI, VIII, R = EtOCOCH2; V, VII, IX, R = Ph; R′ = H (a), Cl (b).
1030

HETEROCYCLIZATION OF N-HETARYL-N′-(PROP-2-EN-1-YL)THIOUREAS
1031
Heterocyclization of N-allyl-N′-hetarylthioureas by the action of sulfuryl chloride (chloroform, 18–25°C)
Initial
compound no.
N-Allylthiourea, g (mmol)
Sulfuryl chloride, ml (mmol)
Product no.
Yield, g (%)
0.290 (1.50)
0.300 (1.05)
0.300 (1.05)
0.300 (1.09)
0.300 (1.09)
0.121 (1.50)
0.085 (1.05)
0.255 (3.15)
0.090 (1.11)
0.180 (2.22)
0.376 (95)
0.259 (69)
0.309 (75)
0.321 (85)
0.362 (87)
I
II
IV
IV
V
VIa
VIb
VIIa
VIIb
V
presence of excess sulfuryl chloride, the cyclization
was accompanied by chlorination of the thiazole ring
to give compounds VIb and VIIb (Scheme 2, see
table). Our results are very consistent with the data of
[2], according to which N-(pyridin-2-yl)-1,3-thiazol-2-
amine readily undergoes bromination at the 5-position
of the thiazole ring under mild conditions; here, the
pyridine ring remains intact. By treatment of hydro-
chlorides VIa, VIb, VIIa, and VIIb with an aqueous
solution of sodium sulfite we obtained free bases
VIIIa, VIIIb, IXa, and IXb.
the bond angles at that atom is 358.6°. Molecules III
in crystal are linked to centrosymmetric dimers via
medium-strength [3] intermolecular hydrogen bonds
N3–H···N2 with the following parameters: N3 ···N2
2.966(5) Å, ∠N3HN2 174(5)° (Fig. 2).
EXPERIMENTAL
1
The H NMR spectra were recorded on a Varian
VXR-300 spectrometer (300 MHz) from solutions in
DMSO-d6 using tetramethylsilane as internal refer-
ence. The X-ray diffraction data for a single crystal of
III, 0.03×0.39×0.48 mm, were acquired at room tem-
perature on a Bruker Apex II automatic CCD diffrac-
tometer (MoKα irradiation, λ = 0.71069 Å, θmax = 23°,
–16 ≤ h ≤ 16, –6 ≤ k ≤ 5, –19 ≤ l ≤ 24). Total of 3560
reflections were measured, 1357 of which were inde-
pendent (Rint = 0.029). Monoclinic crystals with the
Participation of the double bond in the cyclization
1
is confirmed by the H NMR spectra of the products,
which lack signals of the allyl fragment present in
initial compounds I, IV, and V; instead, two multiplets
appear in the δ region 3.71–4.19 ppm due to diastereo-
topic protons of two methylene groups (C4H2 in
the thiazolidine ring and CH2Cl), and a multiplet at
δ 4.14–4.44 ppm is present (3-H, thiazolidine).
1
C3
C2
However, the H NMR spectra did not allow us to
C2
C3
choose between alternative 2-iminothiazolidine and
2-aminodihydrothiazole X structures.
C1
N2
C4
C1
N2
N
C6
C4
N3
Ht
N3
N
CH2Cl
N1
C6
S
H
C5
C5
7
X
C7
C
N1
S1
Therefore, the structure of cyclization product III
was unambiguously proved by X-ray analysis. The
general view of molecule III and principal bond
lengths and bond angles therein are given in Fig. 1.
The five-membered ring S1C6C7C8N3 is not planar:
deviations of atoms from the mean-square plane reach
0.145 Å (envelope conformation); the bond system
S1C6N3C7 is planar within 0.013 Å, and it forms a di-
hedral angle of 22.6° with the S1C8C7 plane. The pyri-
dine ring N1C1C2C3C4C5 is approximately coplanar to
the S1C6C7C8N3 heteroring: the corresponding dihedral
angle is 15.3°. The N3 atom has a planar–trigonal bond
configuration (within experimental error); the sum of
C8
S1
C8
C9
Cl1
Cl1
C9
Fig. 1. Structure of the molecule of N-(5-chloromethyl-1,3-
thiazolidin-2-ylidene)pyridin-2-amine (III) according to the
X-ray diffraction data. Principal bond lengths (Å) and
bond angles (deg): C1–N2 1.397(5), N2–C6 1.299(6), N3–C6
1.330(5), N3–C7 1.435(6), S1–C6 1.767(5), S1–C8 1.825(5),
C7–C8 1.487(7); C6S1C8 90.9(2), C1N2C6 122.0(4), C6N3C7
117.6(4).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 43 No. 7 2007

ZBOROVSKII et al.
1032
in 5 ml of ethanol at 40–50°C, the solution was cooled
to 25–30°C, 5.00 ml (0.051 mol) of allyl isothiocy-
anate was added, and the mixture was heated for 1 h
under reflux. After cooling, the crystalline product was
filtered off, washed in succession with a small amount
of ice-cold ethanol and diethyl ether, and recrystallized
from ethanol. Yield 7.92 g (82%), mp 100–101°C.
1H NMR spectrum, δ, ppm: 4.33 m (2H, CH2-
CH=CH2), 5.18 d (1H, =CH2, J = 10.3 Hz), 5.26 d
(1H, =CH2, J = 17.3 Hz), 5.98 m (1H, CH2CH=CH2),
7.07 m (1H, pyridine), 7.20 m (1H, pyridine), 7.81 (1H,
pyridine), 8.25 m (1H, pyridine), 10.70 br.s (1H, NH),
11.83 br.s (1H, NH). Found, %: C 55.61; H 5.59;
N 21.42; S 16.29. C9H11N3S. Calculated, %: C 55.93;
H 5.74; N 21.74; S 16.59.
c
N-(5-Chloromethyl-1,3-thiazolidin-2-ylidene)-
pyridin-2-amine hydrochloride (II). A solution of
0.121 ml (1.5 mmol) of SO2Cl2 in 5 ml of chloroform
was added over a period of 2 h under stirring at 18–
25°C to a solution of 0.290 g (1.5 mmol) of thiourea I
in 10 ml of chloroform. After 20 h, the solvent was
removed under reduced pressure (~15 mm), the residue
was ground with a few drops of acetone or chloroform,
and the finely crystalline product was filtered off and
washed with pentane. Yield 0.376 g (95%), mp 78–
81°C. 1H NMR spectrum, δ, ppm: 3.20–3.65 br.s (HCl,
H2O), 3.99–4.19 m (4H, 4′-H, CH2Cl), 4.37 m (1H,
5′-H), 7.30–7.41 m (2H, pyridine), 7.95–8.01 m (1H,
pyridine), 8.41 m (1H, pyridine), 10.55–12.55 br.s
(NH). Found, %: C 40.79; H 4.34; Cl 26.60; N 15.75;
S 11.93. C9H11Cl2N3S. Calculated, %: C 40.92; H 4.20;
Cl 26.84; N 15.91; S 12.14.
a
0 0
bb
Fig. 2. Crystal packing of N-(5-chloromethyl-1,3-thiazolidin-
2-ylidene)pyridin-2-amine (III). Intermolecular hydrogen
bonds N3–H···N2 are shown with dotted lines.
following unit cell parameters: a = 15.700(1), b =
6.076(6), c = 22.414(2) Å; β = 104.210(5)°; V =
2072.8(3) Å3; M 227.72; Z = 8; dcalc = 1.46 g/cm3; μ =
5.32 cm–1; F(000) = 944; space group C/2c (no. 15).
The structure was solved by the direct method and was
refined by the least-squares procedure in full-matrix
anisotropic approximation using CRYSTALS software
package [4]; 822 reflections with I > 3σ(I) were used
in the refinement (130 refined parameters, 6.3 reflec-
tions per parameter). All hydrogen atoms were visual-
ized by the difference synthesis of electron density and
were included into the refinement procedure with fixed
positional and thermal parameters. A three-parameter
Chebyshev’s weight scheme [5] was applied (1.65,
0.89, 1.29). The final divergence factors were R =
0.041 and RW = 0.048, GOF 1.074; the residual elec-
tron density from the Fourier difference series was
–0.22 and 0.48 e/A3. The complete set of crystallo-
graphic data for compound III was deposited to the
Cambridge Crystallographic Data Center (entry
no. CCDC 626858).
N-(Prop-2-en-1-yl)-N′-(1,3-thiazol-2-yl)thioureas
IV and V (general procedure). A mixture of 0.03 mol
of 4-phenyl-1,3-thiazol-2-amine or ethyl 2-amino-1,3-
thiazol-4-ylacetate and 5.89 ml (0.06 mol) of allyl iso-
thiocyanate was heated on a boiling water bath for 2 h
in the synthesis of IV or 6–7 h in the synthesis of V.
After cooling, the crystalline product was washed with
cold ethanol and recrystallized from ethanol.
Ethyl {2-[3-(prop-2-en-1-yl)thioureido]thiazol-4-
yl}acetate (IV). Yield 6.58 g (77%), mp 108–109°C.
1H NMR spectrum, δ, ppm: 1.19 t (3H, CH3, J =
7.0 Hz), 3.68 s (2H, CH2CO), 4.09 q (2H, OCH2, J =
7.0 Hz), 4.23 m (2H, CH2CH=CH2), 5.15 d (1H,
=CH2, J = 10.5 Hz), 5.22 d (1H, =CH2, J = 17.4 Hz),
5.86–5.99 m (1H, CH=CH2), 6.91 s (5-H), 9.56 br.s
(1H, NH), 11.70 br.s (1H, NH). Found, %: C 46.17;
H 5.17; N 14.53; S 22.62. C11H15N3O2S2. Calculated,
%: C 46.30; H 5.30; N 14.72; S 22.47.
N-(Prop-2-en-1-yl)-N′-(pyridin-2-yl)thiourea (I)
[6]. Pyridin-2-amine, 4.70 g (0.05 mol), was dissolved
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 43 No. 7 2007

HETEROCYCLIZATION OF N-HETARYL-N′-(PROP-2-EN-1-YL)THIOUREAS
1033
S 18.45. C13H13Cl2N3S2. Calculated, %: C 45.09; H 3.78;
Cl 20.48; N 12.13; S 18.52.
N-(4-Phenyl-1,3-thiazol-2-yl)-N′-(prop-2-en-1-yl)-
thiourea (V). [7]. Yield 5.69 g (69%), mp 177–178°C.
1H NMR spectrum, δ, ppm: 4.29 m (2H, CH2CH=CH2),
5.22 d (1H, =CH2, J = 10.2 Hz), 5.31 d (1H, =CH2, J =
17.1 Hz), 5.94–6.07 m (1H, CH=CH2), 7.31–7.46 m
(3H, Harom), 7.55 s (5-H), 7.86–7.88 m (2H, Harom),
9.62 br.s (1H, NH), 11.78 s (1H, NH). Found, %:
C 56.59; H 4.61; N 15.09; S 23.35. C13H13N3S2. Cal-
culated, %: C 56.70; H 4.76; N 15.26; S 23.29.
5-Chloro-N-(5-chloromethyl-1,3-thiazolidin-2-
ylidene)-4-phenyl-1,3-thiazol-2-amine hydrochlo-
1
ride (VIIb). mp 137–140°C. H NMR spectrum, δ,
ppm: 3.71–3.92 m (4H, 4′-H, CH2Cl), 4.14 m (1H,
5′-H), 4.35–5.10 br.s (HCl, H2O), 7.40–7.51 m (3H,
Harom), 7.92–7.95 m (2H, Harom), 8.33 s (NH). Found,
%: C 40.88; H 3.29; Cl 27.75; N 10.89; S 16.72.
C13H12Cl3N3S2. Calculated, %: C 41.01; H 3.18;
Cl 27.93; N 11.04; S 16.84.
Heterocyclization of N-allylthioureas IV and V
by the action of sulfuryl chloride (general proce-
dure). A solution of a required amount of SO2Cl2 in
5 ml of chloroform was added over a period of 2 h
under stirring at 18–25°C to a solution of 300 mg of
compound IV or V in 20 ml of chloroform. After 20 h,
the solvent was removed under reduced pressure. The
residue was a light yellow solid which was trans-
formed in 20–40 min into a thick oily material. It was
ground with a few drops of acetone or chloroform to
obtain a finely crystalline substance which was washed
with pentane and dried. The yields of hydrochlorides
VIa, VIb, VIIa, and VIIb are given in table.
N-(5-Chloromethyl-1,3-thiazolidin-2-ylidene)-
pyridin-2-amine (III) and N-(5-chloromethyl-1,3-
thiazolidin-2-ylidene)-1,3-thiazol-2-amines VIIIa,
VIIIb, IXa, and IXb (general procedure). A solution
of 0.5 g of hydrochloride II, VIa, VIb, VIIa, or VIIb
in 30 ml of dimethyl sulfoxide was cooled in an ice
bath, and 40–60 ml of a 10% aqueous solution of sodi-
um sulfite was added in small portions under stirring
and cooling over a period of 3 h. After 2–5 h, the finely
crystalline product was filtered off, thoroughly washed
with water, and recrystallized from acetone (III) or
ethanol (VIIIa, VIIIb, IXa, IXb).
Ethyl [2-(5-chloromethyl-1,3-thiazolidin-2-yli-
deneamino)-1,3-thiazol-4-yl]acetate hydrochloride
(VIa). mp 85–87°C. 1H NMR spectrum, δ, ppm: 1.22 t
(3H, CH3, J = 7.2 Hz), 3.65–4.25 br.s (HCl, H2O),
3.74–3.83 m (2H) and 3.91–4.01 m (2H) (4′-H, CH2Cl),
3.79 s (2H, CH2CO), 4.13 q (2H, OCH2, J = 7.2 Hz),
4.44 m (1H, 5′-H), 7.13 s (5-H), 8.36 s (NH). Found,
%: C 36.96; H 4.31; Cl 19.72; N 11.78; S 17.96.
C11H15Cl2N3O2S2. Calculated, %: C 37.08; H 4.24;
Cl 19.90; N 11.79; S 18.00.
N-(5-Chloromethyl-1,3-thiazolidin-2-ylidene)-
pyridin-2-amine (III). Yield 0.39 g (90%), mp 134–
135°C. H NMR spectrum, δ, ppm: 3.68–3.81 m (4H,
4′-H, CH2Cl), 3.89–3.97 m (1H, 5′-H), 6.91 m (1H,
pyridine), 7.15 m (1H, pyridine), 7.64 m (1H, pyri-
dine), 8.23 m (1H, pyridine), 9.02 br.s (NH). Found,
%: C 47.30; H 4.31; Cl 15.48; N 18.28; S 13.91.
C9H10ClN3S. Calculated, %: C 47.47; H 4.43;
Cl 15.57; N 18.45; S 14.08.
1
Ethyl [2-(5-chloromethyl-1,3-thiazolidin-2-yli-
Ethyl [5-chloro-2-(5-chloromethyl-1,3-thiazoli-
din-2-ylideneamino)-1,3-thiazol-4-yl]acetate hydro-
deneamino)-1,3-thiazol-4-yl]acetate (VIIIa). Yield
1
0.202 g (45%), mp 100–101°C. H NMR spectrum, δ,
1
chloride (VIb). mp 73–75°C. H NMR spectrum, δ,
ppm: 1.20 t (3H, CH3, J = 7.2 Hz), 3.62 s (2H,
CH2CO), 3.65–3.88 m (4H, 4′-H, CH2Cl), 4.07–4.15 m
(1H, 5′-H), 4.10 q (2H, OCH2, J = 7.2 Hz), 6.84 s
(5-H), 8.52 br.s (NH). Found, %: C 41.25; H 4.29;
Cl 11.01; N 13.02; S 19.93. C11H14ClN3O2S2. Calculat-
ed, %: C 41.31; H 4.41; Cl 11.08; N 13.14; S 20.05.
ppm: 1.21 t (3H, CH3, J = 7.2 Hz), 3.68 s (2H,
CH2CO), 3.73–3.80 m (2H) and 3.86–3.95 m (2H)
(4′-H, CH2Cl), 4.12 q (2H, OCH2, J = 7.2 Hz), 4.23 m
(1H, 5′-H), 6.20–7.30 br.s (HCl, H2O), 8.33 s (NH).
Found, %: C 33.76; H 3.72; Cl 27.05; N 10.63;
S 16.25. C11H14Cl3N3O2S2. Calculated, %: C 33.81;
H 3.61; Cl 27.22; N 10.75; S 16.41.
Ethyl [5-chloro-2-(5-chloromethyl-1,3-thiazoli-
din-2-ylideneamino)-1,3-thiazol-4-yl]acetate (VIIIb).
1
N-(5-Chloromethyl-1,3-thiazolidin-2-ylidene)-4-
Yield 0.231 g (51%), mp 112–113°C. H NMR spec-
phenyl-1,3-thiazol-2-amine hydrochloride (VIIa).
trum, δ, ppm: 1.20 t (3H, CH3, J = 7.2 Hz), 3.62 s (2H,
CH2CO), 3.65–3.90 m (4H, 4′-H, CH2Cl), 4.07–4.15 m
(1H, 5′-H), 4.11 q (2H, OCH2, J = 7.2 Hz), 8.85 br.s
(NH). Found, %: C 37.15; H 3.62; Cl 19.95; N 11.79;
S 18.02. C11H13Cl2N3O2S2. Calculated, %: C 37.29;
H 3.70; Cl 20.01; N 11.86; S 18.10.
1
mp 111–114°C. H NMR spectrum, δ, ppm: 3.79–
3.99 m (4H, 4′-H, CH2Cl), 4.27–4.30 m (1H, 5′-H),
4.40–5.40 br.s (HCl, H2O), 7.34–7.48 m (3H, Harom),
7.67 s (5-H), 7.94–7.96 m (2H, Harom), 8.35 s (NH).
Found, %: C 44.96; H 3.89; Cl 19.69; N 12.02;
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 43 No. 7 2007

ZBOROVSKII et al.
1034
(Electrophilic Intramolecular Cyclization of Olefins),
N-(5-Chloromethyl-1,3-thiazolidin-2-ylidene)-4-
Kiev: Naukova Dumka, 1990; Orysyk, V.V., Zborov-
skii, Yu.L. Staninets, V.I., Dobosh, A.A., and Khri-
pak, S.M., Khim. Geterotsikl. Soedin., 2003, p. 739; Zbo-
rovskii, Yu.L., Orysyk, V.V., Dobosh, A.A., Stani-
nets, V.I., Pirozhenko, V.V., and Chernega, A.N., Khim.
Geterotsikl. Soedin., 2003, p. 1255; Zborovskii, Yu.L.,
Orysyk, V.V., Staninets, V.I., Nadtochii, S.N., Boguslav-
skii, A.Yu., Sagach, V.F., Dmitrieva, A.V., and Cherne-
ga, A.N. Zh. Org. Farm. Khim., 2003, vol. 1, p. 80.
phenyl-1,3-thiazol-2-amine (IXa). Yield 0.350 g
(79%), mp 159–160°C. H NMR spectrum, δ, ppm:
1
3.62–3.89 m (4H, 4′-H, CH2Cl), 4.06–4.13 m (1H,
5′-H), 7.29–7.33 m (1H, Harom), 7.40–7.45 m (2H,
Harom), 7.52 s (5-H), 7.91–7.94 m (2H, Harom), 8.60 br.s
(NH). Found, %: C 49.54; H 3.79; Cl 11.30; N 13.47;
S 20.55. C13H12ClN3S2. Calculated, %: C 50.39;
H 3.90; Cl 11.44; N 13.56; S 20.70.
2. Bodeker, J., Hauser, S., Selle, U., and Koppel, H.,
5-Chloro-N-(5-chloromethyl-1,3-thiazolidin-2-
ylidene)-4-phenyl-1,3-thiazol-2-amine (IXb). Yield
0.382 g (84%), mp 175–176°C. H NMR spectrum, δ,
ppm: 3.63–3.87 m (4H, 4′-H, CH2Cl), 4.08–4.13 m
(1H, 5′-H), 7.40–7.52 m (3H, Harom), 7.93–7.96 m (2H,
Harom), 8.86 br.s (NH). Found, %: C 45.19; H 3.11;
Cl 20.43; N 12.09; S 18.47. C13H11Cl2N3S2. Calculat-
ed, %: C 45.35; H 3.22; Cl 20.60; N 12.20; S 18.63.
J. Prakt. Chem., 1974, vol. 6, p. 881.
3. Kuleshova, L.N. and Zorkii, P.M., Acta Crystallogr.,
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4. Watkin, D.J., Prout, C.K., Carruthers, J.R., and Better-
idge, P.W., Crystals. Issue 10, Chemical Crystallography
Laboratory, Univ. of Oxford, 1996.
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Sect. A, 1979, vol. 35, p. 698.
1
6. Karanov, E. and Vasil’ev, G., Dokl. Akad. Nauk SSSR,
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