A one-pot, three-component synthesis of thiazolidine-2-thiones

Article abstract of DOI:10.1016/j.tetlet.2012.04.129

An efficient method for the synthesis of thiazolidine-2-thiones is described via regiospecific iodocyclization of an allyl amine, carbon disulfide, and iodine. Dehydrohalogenation of the iodo-derivatives gives thiazole-2(3H)-thiones. In addition, nucleoph

Full text of DOI:10.1016/j.tetlet.2012.04.129

Tetrahedron Letters 53 (2012) 3490–3492
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A one-pot, three-component synthesis of thiazolidine-2-thiones
⇑
Azim Ziyaei-Halimehjani , Katayoun Marjani, Akram Ashouri
Faculty of Chemistry, Tarbiat Moallem University, 49 Mofateh St., Tehran, Iran
a r t i c l e i n f o
a b s t r a c t
Article history:
An efficient method for the synthesis of thiazolidine-2-thiones is described via regiospecific iodocycliza-
tion of an allyl amine, carbon disulfide, and iodine. Dehydrohalogenation of the iodo-derivatives gives
thiazole-2(3H)-thiones. In addition, nucleophilic substitution of the iodine in the products is accom-
plished using NaN3, thiophenol, or dithiocarbamate.
Received 29 January 2012
Revised 10 April 2012
Accepted 27 April 2012
Available online 3 May 2012
Ó 2012 Elsevier Ltd. All rights reserved.
Keywords:
Thiazolidine-2-thione
Regiospecific
Iodocyclization
Dehydrohalogenation
Nucleophilic substitution
S
Oxazolidinones and thiazolidinethiones are the main building
blocks in the structure of linezolid and its thia analogue, which have
attracted attention as a new class of orally active synthetic antibiot-
ics.1–4 Optically active oxazolidinethiones and thiazolidinethiones
have been used extensively as chiral auxiliaries for asymmetric C–
C bond formation.5 Thiazolidinethione chiral auxiliaries also exhibit
several advantages over their oxazolidinone analogues. They can be
directly reduced to aldehydes and displaced by several nucleo-
philes.6 Also, 3-acylthiazolidine-2-thiones have been used as selec-
tive acylating agents for alcohols.7 Furthermore, thiazolidine-2-
thiones have found wide application in coordination chemistry.8
Iodocyclization of unsaturated C–C bonds with a wide variety of
nucleophiles, including N, O, Se, and S, has been studied extensively
and represents a powerful tool for the construction of various
heterocycles.9
Thiazolidine-2-thione has commonly been synthesized by heat-
ing an alkaline solution of a b-amino alcohol and carbon disul-
fide.10 This simple procedure has several disadvantages such as
the use of a strong basic medium, an excess of carbon disulfide,
long reaction times, and high temperature. Therefore, methods
which overcome these drawbacks are required. In continuation of
our interest in developing efficient methods for the synthesis of
novel dithiocarbamates and the use of these intermediates in or-
ganic transformations,11 we describe a simple, new, and efficient
procedure for the synthesis of 5-iodomethyl thiazolidine-2-thiones
2 by iodocyclization of an allyl amine 1, carbon disulfide, and
iodine at room temperature (Scheme 1).
I2
R
N
S
+
CS2
NHR
THF, rt
CH2I
1
2
Scheme 1. Synthesis of 5-iodomethyl thiazolidine-2-thiones 2.
The allyl amines used in this project were synthesized by Mi-
chael addition of allyl amine to activated olefins or by reductive
amination of aldehydes with allyl amine. Cinnamyl amine was syn-
thesized by reduction of the corresponding azide using SnCl2 in
methanol. We optimized the reaction conditions for the key iodo-
cyclization by varying the number of equivalents of amine, carbon
disulfide, I2, and the solvent. The reactions of various allyl amines
were studied and the results are summarized in Table 1. The reac-
tion is regiospecific toward the synthesis of thiazolidine-2-thiones
via a 5-exo-trig mechanism; 6-endo-trig cyclization was not ob-
served. The products were stable for several months. The structures
of the products were confirmed by IR, 1H, and 13C NMR spectros-
copy, and mass spectrometry. According to the literature,12 the
CH2I group in five-membered heterocyclic compounds is observed
at 4–10 ppm in 13C NMR spectra, while the –CHI group in a six-
membered heterocycle appears above 14 ppm. The reaction of
dithiocarbamate salts with iodine normally gives thiuram disul-
fides,13 but reaction of dithiocarbamates prepared with allyl amine
derivatives and iodine affords thiazolidine-2-thiones as the sole
products.14 We performed the reaction in basic medium (using
NaHCO3) and the yield was low when run in neutral conditions.
The reaction of cinnamyl amine with carbon disulfide and iodine
was not successful.
⇑
Corresponding author. Tel.: +98 (21) 88848949; fax: +98 (21) 88820992.
E-mail addresses: ziyaei@tmu.ac.ir, azimkzn@yahoo.com (A. Ziyaei-Halimehjani).
0040-4039/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tetlet.2012.04.129

A. Ziyaei-Halimehjani et al. / Tetrahedron Letters 53 (2012) 3490–3492
3491
Table 1
S
S
Synthesis of thiazolidine-2-thiones via iodocyclizationa
DBU ( 2 eq)
NC
NC
NC
N
S
N
N
S
CH2Cl2/2 h
rt, 96%
S
CH2I
2b
CH2
I2
5
R
N
S
+
CS2
NHR
THF, rt
DBU (2 eq)
CH2Cl2/6 h
CH2I
1
2
Entry
1
Amine
Product
Yieldb (%)
55
rt, 98%
SCH3
S
S
S
S
H2N
NC
CH3I
2a
I-
N
HN
S
I
CH3
THF/rt
100%
CH3
H
N
S
7
6
NC
2b
I
NC
2
3
46
60
N
N
S
Scheme 3. Dehydrohalogenation of compound 2b.
S
N
H
2c
S
I
S
S
N
H
NC
N
S
2d
N
S
4
5
6
7
8
9
59
62
68
75
60
62
H3CO
Br
S
CH2N3
8 (53%)
I
H3CO
Br
NaN3/DMF
24 h/rt
NC
N
S
S
N
CH2I
H
2e
N
S
2b
S
I
NC
N
S
S
S
N
CH2
5 (47%)
H
2f
N
S
O2N
H3C
Cl
I
O2N
H3C
Cl
N
H
Scheme 4. Nucleophilic substitution of compound 2b with NaN3.
2g
N
S
I
S
N
S
H
PhSH/K2CO3
NC
2h
N
S
S
N
S
I
S
S
DMF
24 h/rt
96%
S
N
H
9
S
2i
N
S
S
NO2
NC
S
N
I
NO2
I
H
N
I
diethylamine
CS2
2b
NC
N
S
N
10
65
2j
S
N
S
rt/18 h
90%
10
a
Reaction conditions: amine (3 mmol), CS2 (5 mmol), I2 (3.3 mmol), 24 h.
Isolated yield.
b
Scheme 5. Nucleophilic substitutions of compound 2b.
S
S
I2
the substituted 2-methylthio-thiazolium iodide 7 by reaction with
methyl iodide. (Scheme 3). Compound 7 is an example member of
an important family of ionic liquids.16
NH
CS2
IH2C
CH2I
N
THF, rt
35%
I-
3
4
Also, nucleophilic substitution of iodo products is an effective
method for the synthesis of various valuable molecules. For this
purpose, the reaction of 2b with NaN3 was investigated. We ob-
served that the azide product 8 and kinetic dehydrohalogenation
product 5 were obtained in a 53:47 ratio (Scheme 4).17 In addition,
reaction of thiophenol with 2b was carried out in the presence of
K2CO3 in DMF and the corresponding thioether 9 was obtained in
excellent yield (Scheme 5).18 Furthermore, the one-pot, three-com-
ponent reaction of diethylamine, carbon disulfide, and compound
2b was carried out under neat conditions to afford the correspond-
ing dithiocarbamate 10 in an excellent yield (Scheme 5).19 Substi-
tution of the iodide with amines was not successful.
In conclusion, we have reported a new route toward the synthe-
sis of 5-(iodomethyl)-thiazolidine-2-thiones via the one-pot,
three-component reaction of allyl amine, carbon disulfide, and io-
dine. The reaction is simple, efficient, regiospecific, and gives good
to high yields of products. Dehydrohalogenation of product 2b
gave the corresponding thiazole-2(3H) thione in high yield. In
addition nucleophilic substitution of the iodine group of 2b was
accomplished with NaN3, thiophenol, and diethylamine/CS2.
Scheme 2. Synthesis of 2,6-bis(iodomethyl)-2,3,5,6-tetrahydrothiazolo[2,3-b]thia-
zol-4-ium iodide 4.
The reaction of diallyl amine 3 with carbon disulfide and iodine
gave 2,6-bis(iodomethyl)-2,3,5,6-tetrahydrothiazolo[2,3-b]thiazol-
4-ium iodide 4 as the only product. The pure product was obtained
from the reaction mixture by simple filtration and was character-
ized using 1H and 13C NMR spectroscopy and CHN analysis
(Scheme 2).14
The presence of the iodo group in the products allowed further
structural elaboration. Dehydrohalogenation of compound 2b
using DBU was examined as a model reaction. When the reaction
was carried out over a short time (1–2 h), only the exocyclic double
bond containing product 5 was obtained as the kinetic product,
while over a longer reaction time (more than 6 h), the endocyclic
double bond containing product 6 was obtained as the thermody-
namic product in an excellent yield.15 In addition, we have shown
that the thiazole-2(3H)-thione 6 could be converted simply into

3492
A. Ziyaei-Halimehjani et al. / Tetrahedron Letters 53 (2012) 3490–3492
EtOH. In the case of diallyl amine (1 equivalent), I2 (2.5 equivalents) was used
Acknowledgements
and the product was obtained by simple filtration and washing the precipitate
with Et2O. Characterization data for 3-(4-chlorobenzyl)-5-(iodomethyl)thia-
zolidine-2-thione (2h) (entry 8, Table 1): mp 62–64 °C; IR (KBr): 1490, 1316,
We are grateful to the Faculty of Chemistry of Tarbiat Moallem
University for supporting this work.
1158, 1014, 794, 564 cmÀ1 1H NMR (300 MHz, CDCl3): d (ppm) = 3.23 (1H, t,
;
J = 10.4 Hz), 3.37 (1H, dd, J = 10.6, 4.3 Hz), 3.81–4.02 (3H, m), 4.86 (1H, d,
J = 14.6 Hz), 4.99 (1H, d, J = 14.6 Hz), 7.27–7.38 (4H,m); 13C NMR (75 MHz,
CDCl3): d (ppm) = 7.0, 43.5, 51.9, 60.8, 129.3, 129.6, 132.4, 133.1, 196.5; MS
(EI): m/z 383 (M+), 349, 182, 167, 149, 125 (100), 89, 69, 57, 41.
Supplementary data
15. Synthesis of 3-[(5-methylene-2-thioxothiazolidin-3-yl)] propanenitrile (5) and 3-
[(5-methyl-2-thioxothiazol-3(2H)-yl)] propanenitrile (6) by dehydrohalogenation
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.tetlet.2012.04.
129.
of
3-[(5-(iodomethyl)-2-thioxothiazolidin-3-yl)]propanenitrile
(2b):
DBU
(2 mmol) was added to a solution of 2b (1 mmol) in CH2Cl2 (5 mL), and the
resulting mixture was stirred for 1 to 6 h at rt. H2O (10 mL) was added and the
product was extracted with CH2Cl2 (2 Â 10 mL). The combined organic layers
were washed with H2O (10 mL) and brine (10 mL) and dried over Na2SO4 and
evaporated in vacuo. The residue was pure enough to give satisfactory
spectroscopic data. When the reaction was quenched after 1 h, compound 5
was obtained as the sole product (96% isolated yield). Increasing the reaction
time to 6 h gave compound 6 as the thermodynamic product (98%). Compound
5: 1H NMR (500 MHz, CDCl3): d (ppm) = 2.85 (2H, t, J = 6.5 Hz), 4.02 (2H, t,
J = 6.5 Hz), 4.90 (2H, t, J = 2.5 Hz), 5.12 (1H, d, J = 2.3 Hz), 5.25 (1H, d,
References and notes
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J = 2.3 Hz); 13C NMR (125 MHz, CDCl3):
d (ppm) = 15.7, 44.8, 63.4, 106.4,
118.3, 135.9, 195.7; MS (EI): m/z 184 (M+) (100), 131, 111, 71, 54, 41; HRMS
calcd for C7H8N2NaS2 (M+Na+), 207.0027; Found 207.0021; Compound 6: mp
68–72 °C; 1H NMR (300 MHz, acetone-d6): d (ppm) = 2.23 (3H, d, J = 1.2 Hz),
3.09 (2H, t, J = 6.6 Hz), 4.44 (2H, t, J = 6.6 Hz), 7.26 (1H, J = 1.2 Hz); 13C NMR
(75 MHz, acetone-d6): d (ppm) = 12.4, 16.5, 45.7, 118.0, 124.2, 129.7, 188.5; MS
(EI): m/z 184 (M+) (100), 152, 131, 98, 86, 72, 59, 41; HRMS calcd for
C7H8NNaS2 (M+Na+), 207.0027; Found 207.0021.
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16. Synthesis of 3-[(2-cyanoethyl)-5-methyl-2-(methylthio)thiazol-3-ium] iodide (7)
from 3-[(5-methyl-2-thioxothiazol-3(2H)-yl)] propanenitrile (6): In a test tube
equipped with a magnetic stir bar were added compound 6 (1 mmol) and THF
(5 mL). To this solution was added MeI (3 mmol) and the mixture was stirred
for 10 h. The resulting precipitate was filtered and washed with excess THF to
give the pure 7 in quantitative yield. mp 106–109 °C. 1H NMR (500 MHz,
DMSO-d6+CDCl3): d (ppm) = 2.53 (3H, s), 2.98 (3H, s), 3.20 (2H, t, J = 6.5 Hz),
4.63 (2H, t, J = 6.5 Hz), 8.29 (1H, s) ppm; 13C NMR (125 MHz, DMSO-d6+CDCl3):
d (ppm) = 12.8, 17.3, 19.3, 47.9, 116.6, 134.8, 134.9, 174.9.; MS (EI): m/z 326
(M+), 294, 184 (100), 149, 142, 131, 123, 105, 73, 57, 41; HRMS calcd for
C8H11I2N2S2 (M+I-), 452.8453; Found 452.8458.
17. Synthesis of 3-[5-(azidomethyl)-2-thioxothiazolidin-3-yl] propanenitrile (8) from
2b: In a test tube equipped with a magnetic stir bar, compound 2b (2 mmol),
DMF (10 mL), and NaN3 (5 mmol) were added. The mixture was stirred
overnight at room temperature, then quenched with H2O and extracted with
EtOAc (2 Â 10 mL). The organic layer was washed with H2O (4 Â 20 mL) and
dried over anhydrous Na2SO4. Evaporation of the solvent gave the crude
product. NMR analysis showed that the mixture contained 53% of the azide
product 8 and 47% of kinetic dehydrohalogenation product 5. Spectroscopic
data for compound 8: 1H NMR (500 MHz, CDCl3): d (ppm) = 2.76–2.98 (2H, m),
3.62 (2H, m), 3.79–3.91 (2H, m), 4.07–4.13 (2H, m), 4.32 (1H, m) ppm; 13C NMR
(125 MHz, CDCl3): d (ppm) = 15.8, 42.8, 45.2, 54.3, 60.8, 118.3, 196.5.MS (EI):
m/z 227 (M+), 184, 170, 167, 144, 118, 111, 72 (100), 59, 54, 41.
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18. Synthesis of 3-[5-(phenylthiomethyl)-2-thioxothiazolidin-3-yl] propanenitrile (9)
from 2b: In a test tube equipped with a magnetic stir bar, compound 2b
(2 mmol), DMF (10 mL), thiophenol (3 mmol), and K2CO3 (3 mmol) were
added, respectively. The mixture was stirred overnight at room temperature,
then quenched with H2O (5 mL) and extracted with EtOAc (2 Â 10 mL). The
organic layer was washed with saturated NaHCO3 solution and with H2O
(4 Â 20 mL) and dried over anhydrous Na2SO4. Evaporation of the solvent gave
the corresponding thioether 9 in 95% yield. The product was pure enough to
give satisfactory spectroscopic data. 1H NMR (500 MHz, CDCl3):
d
(ppm) = 2.76–2.84 (2H, m), 3.17–3.22 (2H, m), 3.67–3.97 (3H, m), 4.23–4.26
(2H, m) 7.25–7.38 (5H, m); 13C NMR (125 MHz, CDCl3) d (ppm) = 15.8, 39.1,
43.4, 45.3, 61.6, 118.3, 127.9, 129.8, 131.5, 137.3, 197.1; MS (EI): m/z = 294
(M+), 218 (100), 185, 163, 154, 141, 123, 109, 73, 65, 57, 51, 45, 41; HRMS calcd
for C13H14N2NaS3 (M+Na+), 317.0217; Found 317.0211.
19. Synthesis of [3-(2-cyanoethyl)-2-thioxothiazolidin-5-yl]methyl diethylcarbamodi-
thioate (10) from 2b: In
a test tube equipped with a magnetic stir bar,
12. (a) Mancini, F.; Piazza, M. G.; Trombini, C. J. Org. Chem. 1991, 56, 4246–4252;
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2000, 65, 4826–4829.
compound 2b (2 mmol), CS2 (6 mmol), and diethylamine (4 mmol) were
added, respectively. The mixture was stirred overnight at room temperature,
then quenched with H2O (5 mL) and extracted with EtOAc (2 Â 10 mL). The
organic layer was washed with H2O (2 Â 20 mL) and dried over anhydrous
Na2SO4. Evaporation of the solvent gave the corresponding dithiocarbamate 10
in 90% isolated yield. 1H NMR (500 MHz, CDCl3): d (ppm) = 1.29 (6H, m), 2.85–
2.91 (2H, m), 3.66–3.79 (4H, m), 3.96–4.10 (5H, m) 4.23 (1H, m), 4.32 (1H, m);
13C NMR (125 MHz, CDCl3): d (ppm) = 11.9, 13.0, 15.8, 40.8, 43.6, 45.5, 47.5,
50.5, 61.9, 118.4, 193.7, 197.3; MS (EI): m/z = 334 (M+H)+, 185 (100), 149, 132,
116, 84, 60, 41; HRMS calcd for C12H19N3NaS4 (M+Na+), 356.036; Found
356.0354.
13. Field, L.; Buckman, J. D. J. Org. Chem. 1968, 33, 3865–3871.
14. General Procedure for synthesis of N-substituted-5-(iodomethyl)-thiazolidine-2-
thiones: In a test tube equipped with a magnetic stir bar, N-substituted allyl
amine (3 mmol), THF (5 mL), and CS2 (5 mmol) were added. The mixture was
stirred for 20 min, I2 (3.3 mmol) was added and the mixture stirred for 24 h at
room temperature. After completion, the mixture was treated with 5 mL
aqueous NaHSO3 solution (2 M) and extracted with CH2Cl2 (2 Â 10 mL). The
organic layer was dried over Na2SO4 and evaporated under reduced pressure to
give the crude products. Purification was achieved by recrystallization from