Synthesis of 2-(5-substituted-1,3,4-thiadiazolo-2-ylimino)-4- thiazolidinones under microwave irradiation

Article abstract of DOI:10.1080/00397910701845852

Fifteen 2-(5-substituted-1,3,4-thiadiazolo-2-ylimino)-4-thiazolidinones were efficiently synthesized from the reaction of ammonium thiocyanate with 2-chloro-N-(5-substutited-1,3,4-thiadiazolo-2-yl)acetamides under microwave irradiation. The target compoun

Full text of DOI:10.1080/00397910701845852

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Synthesis of
2‐(5‐Substituted‐1,3,4‐thiadiazolo‐2‐ylimino)‐4‐th
under Microwave Irradiation
Xi-Cun Wang a , Guo-Li Huang a , Zheng-Jun Quan a , Cheng-Wei Lv a & Wen-
Long Yang a
a Gansu Key Laboratory of Polymer Materials, College of Chemistry and
Chemical Engineering, Northwest Normal University, Lanzhou, Gansu, China
Published online: 22 Feb 2008.
To cite this article: Xi-Cun Wang , Guo-Li Huang , Zheng-Jun Quan , Cheng-Wei Lv & Wen-Long Yang (2008):
Synthesis of 2‐(5‐Substituted‐1,3,4‐thiadiazolo‐2‐ylimino)‐4‐thiazolidinones under Microwave Irradiation,
Synthetic Communications: An International Journal for Rapid Communication of Synthetic Organic Chemistry,
38:6, 973-982
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Synthetic Communicationsw, 38: 973–982, 2008
Copyright # Taylor & Francis Group, LLC
ISSN 0039-7911 print/1532-2432 online
DOI: 10.1080/00397910701845852
Synthesis of 2-(5-Substituted-1,3,4-
thiadiazolo-2-ylimino)-4-thiazolidinones
under Microwave Irradiation
Xi-Cun Wang, Guo-Li Huang, Zheng-Jun Quan,
Cheng-Wei Lv, and Wen-Long Yang
Gansu Key Laboratory of Polymer Materials, College of Chemistry and
Chemical Engineering, Northwest Normal University, Lanzhou, Gansu,
China
Abstract: Fifteen 2-(5-substituted-1,3,4-thiadiazolo-2-ylimino)-4-thiazolidinones
were efficiently synthesized from the reaction of ammonium thiocyanate with
2-chloro-N-(5-substutited-1,3,4-thiadiazolo-2-yl)acetamides
under
microwave
irradiation. The target compounds were obtained in better yields (75–98%) and
shorter time (5 min) than with conventional heating.
Keywords: microwave irradiation, synthesis, 1,3,4-thiadiazoles, 4-thiazolidinones
INTRODUCTION
The 1,3,4-thiadiazole derivatives have attracted continued interest over the
years because of their varied biological activities.[1,2] In particular, a large
number of 4-thiazolidinone derivatives possess antituberculosis, anticancer,
antibacterial, antifungal, and anticonvulsant activities.[3–9] Therefore, 1,3,4-
thiadiazole and 4-thiazolidone moieties are prospective scaffolds for the
design of drugs. There have some reports for the synthesis of 3-nonsubstituted
4-thiazolidinones.[10,11] However, these reactions suffered from drawbacks
such as long reaction times, the use of high boiling solvents, low yields,
Received in Japan December 5, 2007
Address correspondence to Xi-Cun Wang, Gansu Key Laboratory of Polymer
Materials, College of Chemistry and Chemical Engineering, Northwest Normal
University, Lanzhou, Gansu 730070, China. E-mail: wangxicun@nwnu.edu.cn
973

974
X.-C. Wang et al.
and use of reactants with high toxicity, which limit their use for the synthesis
of complex molecules. A simple and efficient approach for the synthesis of
functionalized 4-thiazolidinone is our interest.
Moreover, microwave (MW) irradiation is currently used to carry out a
wide range of reactions.[12] Compared with the traditional reactions under
refluxing, the MW reaction technique is often rapid and most convenient,
occurs in high yields, and has stereoselective, environmental, and economic
advantages.
Given this background, we have designed and synthesized a series of new
compounds containing the 1,3,4-thiadiazole ring and 4-thiazolidinone moiety
under MW irradiation.
RESULTS AND DISCUSSION
As described in Scheme 1, the starting material 2-amino-5-aryloxymethy-
lene/aryl-1,3,4-thiadiazoles (1a–o) were synthesized as in our previous
work.[13] 2-Chloro-N-(5-aryloxymethylene/aryl-1,3,4-thiadiazolo-2-yl)ace-
tamides (2a–o) were obtained from the reaction of 1a–o and chloroacetyl
chloride in the presence of anhydrous potassium carbonate. Compounds
(2a–o) were treated with ammonium thiocyanate in N,N-dimethylforma-
mide (DMF) under MW irradiation to provide 2-(5-aryloxymethylene/
aryl-1,3,4-thiadiazolo-2-ylimino)thiazolidin-4-one (3a–o).
Preliminary experiments to examine the reaction time, the solvent, and
irradiation power were performed using 2a (1.0 mmol) and ammonium thio-
cyanate (1.5 mmol) as a model system to synthesize the compound 3a
(Table 1). First, various reaction times and irradiation power were tested
using DMF (4 mL) as a solvent (Table 1, entries 1–5). All comparative
reactions were conducted under optimized conditions, and compound 3a
was obtained under MW irradiation. The best yield of 3a (92%) was
obtained by carrying out the reaction in DMF under MW irradiation
(350 W) for 5 min. Second, other solvents were tested including ethanol
(EtOH), acetonitrile (MeCN), dimethyl sulfoxide (DMSO), and tetrahydro-
furan (THF) (Table 1, entries 6–9). In general, the use of DMF and DMSO
resulted in a faster reaction with a higher yield, in contrast to a reaction in
Scheme 1. R ¼ C6H5OCH2 (a), 2-ClC6H4OCH2 (b), 2-CH3C6H4OCH2 (c),
4-CH3C6H4OCH2 (d), 4-ClC6H4OCH2 (e), 4-CH3OC6H4OCH2 (f), 2-CH3OC6H4-
OCH2 (g), 3-CH3C6H4OCH2 (h), 3-NO2C6H4OCH2 (i), 4-NO2C6H4OCH2 (j), 2,4-Cl2-
C6H3OCH2 (k), C6H5 (l), 2-ClC6H4 (m), 3-CH3C6H4 (n), and 3-NO2C6H4 (o).

2-(5-Substituted-1,3,4-thiadiazolo-2-ylimino)-4-thiazolidinones
975
Table 1. Synthesis of 3a (MW ¼ microwave irradiation; Da ¼ conventional heating)
Mode of
activation
Power/
temp.
Yield
(%)b
Entry
Solvent
Time
1
2
DMF
DMF
DMF
DMF
DMF
EtOH
MeCN
DMSO
THF
MW
MW
MW
MW
MW
MW
MW
MW
MW
D
3 min
5 min
7 min
5 min
5 min
5 min
5 min
5 min
5 min
8 h
350 W
350 W
350 W
210 W
490 W
350 W
350 W
350 W
350 W
808C
56
92
3
92
71
4
5
63
6
,10
Trace
82
7
8
9
0
82
10
11
DMF
DMSO
D
8 h
808C
80
aThe reaction was conducted with 2a (1.0 mmol) and ammonium thiocyanate
(1.5 mmol) at 808C.
All the products were investigated thoroughly by 1H NMR, 13C NMR, IR, and
element analysis.
bIsolated yields.
less polar THF. Third, the reaction was also carried out with conventional
heating (Table 1, entries 10 and 11) but requires extended heating time
(8 h), providing the product in a lower yield (80–82%).
The IR spectrum of 2a–o displayed bands at 3201–3163 and 1713–
1702 cm21 due to -NH- and -C55O stretching frequencies, respectively. The
1H NMR spectrum of 2a displayed a singlet at d 11.62, which accounts for
the NH proton, and a multiplet appeared at d 7.35–6.99, which accounts for
five aromatic protons of the phenyl ring. Two singlets appeared at d 5.52 and
4.54 due to two methylene protons each on the OCH2 and ClCH2 protons.
The mass spectrum of 2a gave a molecular ion peak at m/z 283 (16.5%), and
protonated molecular ion peak at m/z 285 (6.5%), which are in agreement
with its molecular formula C11H10ClN3O2S. Other prominent fragment ions
appeared at m/z 192 (23%), 190 (61%), 114 (100%), and 94 (25%).
The formation of 2-(5-aryloxymethylene/aryl)-1,3,4-thiadiazolo-2-yli-
1
mino)thiazolidin-4-one (3a–o) was confirmed by recording H NMR, 13C
NMR, and mass spectra. The IR spectrum of 3a–o displayed bands at
3168–3102 and 1737–1721 cm21 due to -NH- and -C55O stretching frequen-
1
cies, respectively. The H NMR spectrum of 3a exhibited two singlets at d
4.10 and 5.48, which account for two methylene protons each on the SCH2
and OCH2 protons. Aromatic protons resonated as a multiplet at d 6.99–
7.35, and a singlet appeared at d 12.37, which accounts for the NH proton.
The 13C NMR displayed peaks at 35.80 (CH2), 64.50 (CH2), 115.10 (2C),
121.85, 129.85 (2C), 157.42, 163.35, 166.37, 171.55, and 174.17 (C55O),
which account for all the carbon atoms in the molecule. The mass spectrum

976
X.-C. Wang et al.
of 3a exhibited a molecular ion peak at m/z 306 (5%) in accordance with its
molecular formula C12H10N4O2S2. Other prominent peaks appeared at m/z
214 (11%), 213 (100%), 159 (26%), 131 (9%), 127 (25%), and 94 (6%).
In conclusion, we have described a fast, easy, and efficient protocol for the
preparation of 2-(5-aryloxymethylene/aryl-1,3,4-thiadiazolo-2-ylimino)-4-
thiazolidinones under MW irradiation. The ease of the reaction procedure
and workup, high yields, and very short reaction times make this procedure
a useful and attractive alternative to the currently available methods.
EXPERIMENTAL
All reagents were obtained commercially and used without further purification.
Melting points were determined on an XT-4 electrothermal micromelting-
point apparatus and are uncorrected. IR spectra were recorded using KBr
pellets on Nicolet Avatar 36 fourier transform infrared (FT-IR) spectropho-
tometer. NMR spectra were recorded at 400 (1H) and 100 (13C) MHz, respect-
ively, on a Varian Mercury plus-400 instrument using DMSO as solvent and
TMS as internal standard. Mass spectroscopy (MS) spectra were recorded on
a Trace DSQ mass spectrometer. Elemental analyses were performed on a
Carlo-Erba 1106 Elemental Analysis instrument. MW experiments were
carried out in a domestic oven operating at a frequency of 2450 MHz.
General Synthetic Procedure for Compounds 2a–o
Chloroacetyl chloride (0.57 g, 5.0 mmol) was added dropwise to a solution of
compound (1a–o) (5.0 mmol) and anhydrous potassium carbonate (0.69 g,
5.0 mmol) in dry DMF (20 mL). The mixture was stirred for 4 h at room temp-
erature, then poured onto ice water. The obtained precipitate was filtered off,
washed with water (3 ꢀ 5 mL), and recrystallized from EtOH–DMF to give
the products.
Data
Compound 2a. Yield: 89%. White crystals. Mp: 182–1838C (1588C [14]). 1H
NMR (400 MHz, DMSO-d6) d (ppm): 11.62 (s, 1H, NH), 7.35–6.99 (m, 5H,
ArH), 5.52 (s, 2H, OCH2), 4.54 (s, 2H, ClCH2). IR (KBr) n: 3178, 1707,
1591 cm21. Anal. calcd. for C11H10ClN3O2S: C, 46.56; H, 3.55; N, 14.81.
Found: C, 46.77; H, 3.56; N, 14.74.
Compound 2b. Yield: 91%. White crystals. Mp: 196–1978C (1668C [14]). 1H
NMR (400 MHz, DMSO-d6) d (ppm): 11.61 (s, 1H, NH), 7.37–7.01 (m, 4H,
ArH), 5.51 (s, 2H, OCH2), 4.53 (s, 2H, ClCH2). IR (KBr) n: 3198, 1708,

2-(5-Substituted-1,3,4-thiadiazolo-2-ylimino)-4-thiazolidinones
977
1583 cm21. Anal. calcd. for C11H9Cl2N3O2S: C, 41.52; H, 2.85; N, 13.21.
Found: C, 41.35; H, 2.86; N, 13.27.
Compound 2c. Yield: 90%. White crystals. Mp: 225–2278C (1528C [14]). 1H
NMR (400 MHz, DMSO-d6) d (ppm): 11.60 (s, 1H, NH), 7.10–6.99 (m, 4H,
ArH), 5.51 (s, 2H, OCH2), 4.52 (s, 2H, ClCH2), 2.24 (s, 3H, CH3); IR (KBr) n:
3192, 1705, 1583 cm21. Anal. calcd. for C12H12ClN3O2S: C, 48.40; H, 4.06;
N, 14.11. Found: C, 48.60; H, 4.07; N, 14.04.
Compound 2d. Yield: 91%. White crystals. Mp: 185–1868C (1388C [14]). 1H
NMR (400 MHz, DMSO-d6) d (ppm): 11.60 (s, 1H, NH), 7.00 (d, J ¼ 8.0 Hz,
2H, ArH), 7.15 (d, J ¼ 8.0 Hz, 2H, ArH), 5.53 (s, 2H, OCH2), 4.52 (s, 2H,
ClCH2), 2.23 (s, 3H, CH3). IR (KBr) n: 3193, 1706, 1582 cm21. Anal.
calcd. for C12H12ClN3O2S: C, 48.40; H, 4.06; N, 14.11. Found: C, 48.61;
H, 4.08; N, 14.05.
Compound 2e. Yield: 86%. White crystals. Mp: 178–1808C (1608C [14]). 1H
NMR (400 MHz, DMSO-d6) d (ppm): 11.61 (s, 1H, NH), 7.21 (d, J ¼ 8.4 Hz,
2H, ArH), 7.44 (d, J ¼ 8.4 Hz, 2H, ArH), 5.53 (s, 2H, OCH2), 4.51 (s, 2H,
ClCH2); IR (KBr) n: 3195, 1707, 1585 cm21
. Anal. calcd. for
C11H9Cl2N3O2S: C, 41.52; H, 2.85; N, 13.21. Found: C, 41.70; H, 2.86; N,
13.27.
Compound 2f. Yield: 87%. White crystals. Mp: 179–1808C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 11.60 (s, 1H, NH), 7.00 (d, J ¼ 8 Hz, 2H,
ArH), 6.87 (d, J ¼ 8 Hz, 2H, ArH), 5.52 (s, 2H, OCH2), 4.51 (s, 2H,
ClCH2), 3.71 (s, 3H, CH3). IR (KBr) n: 3179, 1705, 1581 cm21. Anal.
calcd. for C12H12ClN3O3S: C, 45.94; H, 3.85; N, 13.39. Found: C, 46.13;
H, 3.86; N, 13.34.
Compound 2g. Yield: 85%. White crystals. Mp: 201–2028C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 11.59 (s, 1H, NH), 6.90–6.83 (m, 4H,
ArH), 5.50 (s, 2H, OCH2), 4.51 (s, 2H, ClCH2), 3.70 (s, 3H, CH3). IR
(KBr) n: 3181, 1706, 1583 cm21. Anal. calcd. for C12H12ClN3O3S: C,
45.94; H, 3.85; N, 13.39. Found: C, 46.16; H, 3.84; N, 13.45.
Compound 2h. Yield: 85%. White crystals. Mp: 174–1768C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 11.61 (s, 1H, NH), 7.11–6.80 (m, 4H,
ArH), 5.51 (s, 2H, OCH2), 4.53 (s, 2H, ClCH2), 2.21 (s, 3H, CH3). IR
(KBr) n: 3190, 1708, 1580 cm21. Anal. calcd. for C12H12ClN3O2S: C,
48.40; H, 4.06; N, 14.11. Found: C, 48.19; H, 4.07; N, 14.17.
Compound 2i. Yield: 80%. White crystals. Mp: 200–2028C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 11.65 (s, 1H, NH), 7.35–6.99 (m, 4H,
ArH), 5.54 (s, 2H, OCH2), 4.56 (s, 2H, ClCH2). IR (KBr) n: 3163, 1703,

978
X.-C. Wang et al.
1616 cm21. Anal. calcd. for C11H9ClN4O4S: C, 40.19; H, 2.76; N, 17.04.
Found: C, 40.38; H, 2.77; N, 17.12.
Compound 2j. Yield: 81%. White crystals. Mp: 182–1848C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 11.64 (s, 1H, NH), 8.25 (d, J ¼ 8 Hz, 2H,
ArH), 7.30 (d, J ¼ 8 Hz, 2H, ArH), 5.60 (s, 2H, OCH2), 4.53 (s, 2H, ClCH2).
IR (KBr) n: 3167, 1704, 1610 cm21. Anal. calcd. for C11H9ClN4O4S: C,
40.19; H, 2.76; N, 17.04. Found: C, 40.00; H, 2.77; N, 17.11.
Compound 2k. Yield: 85%. White crystals. Mp: 200–2028C (1488C [14]). 1H
NMR (400 MHz, DMSO-d6) d (ppm): 11.61 (s, 1H, NH), 7.45–7.06 (m, 3H,
ArH), 5.51 (s, 2H, OCH2), 4.55 (s, 2H, ClCH2). IR (KBr) n: 3166, 1704, 1605,
cm21. Anal. calcd. for C11H8Cl3N3O2S: C, 37.47; H, 2.29; N, 11.92. Found: C,
37.65; H, 2.30; N, 11.88.
Compound 2l. Yield: 86%. Yellow crystals. Mp: 198–2008C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 11.64 (s, 1H, NH), 7.94–7.55 (m, 5H, ArH),
4.58 (s, 2H, ClCH2). IR (KBr) n: 3184, 1705, 1571 cm21. Anal. calcd. for
C10H8ClN3OS: C, 47.34; H, 3.18; N, 16.56. Found: C, 47.13; H, 3.19; N, 16.49.
Compound 2m. Yield: 81%. White crystals. Mp: 210–2118C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 11.63 (s, 1H, NH), 7.47–7.19 (m, 4H,
ArH), 4.57 (s, 2H, ClCH2). IR (KBr) n: 3181, 1703, 1578 cm21. Anal.
calcd. for C10H7Cl2N3OS: C, 41.68; H, 2.45; N, 14.58. Found: C, 41.86; H,
2.46; N, 14.65.
Compound 2n. Yield: 91%. Yellow crystals. Mp: 206–2088C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 11.62 (s, 1H, NH), 7.24–7.00 (m, 4H,
ArH), 4.56 (s, 2H, ClCH2), 2.31 (s, 3H, CH3). IR (KBr) n: 3201, 1702,
1575 cm21. Anal. calcd. for C11H10ClN3OS: C, 49.35; H, 3.76; N, 15.69.
Found: C, 49.58; H, 3.75; N, 15.76.
Compound 2o. Yield: 74%. White crystals. Mp: 225–2278C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 11.67 (s, 1H, NH), 8.44–7.62 (m, 4H, ArH),
4.61 (s, 2H, ClCH2). IR (KBr) n: 3176, 1713, 1585 cm21. Anal. calcd. for
C10H7ClN4O3S: C, 40.21; H, 2.36; N, 18.76. Found: C, 40.38; H, 2.37; 18.84.
General Synthetic Procedure for Compounds 3a–o
The mixture of compound (2a–o) (1.0 mmol) and ammonium thiocyanate
(0.11 g, 1.5 mmol) in DMF (4 mL) was placed into a Pyrexw open vessel
and irradiated in a domestic microwave oven at 350 W for 5 min (max.
temp 1558C). Progress of the reaction was monitored by thin-layer chromato-
graphy (TLC). After completion of the reaction, the reaction mixture was left

2-(5-Substituted-1,3,4-thiadiazolo-2-ylimino)-4-thiazolidinones
979
to cool and poured onto ice water. The resulting precipitate was collected by
filtration and recrystallized from EtOH–DMF to obtain 3a–o.
Data
Compound 3a. Yield: 92%. Yellow crystals. Mp: 226–2288C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 12.37 (s, 1H, NH), 7.35–6.99 (m, 5H,
ArH), 5.48 (s, 2H, OCH2), 4.10 (s, 2H, SCH2). 13C NMR (100 MHz,
DMSO-d6) d: 174.16, 171.55, 166.37, 163.35, 157.42, 129.85, 121.85,
115.10, 64.50, 35.08. MS: m/z 306 (5%, Mþ), 213 (100%). IR (KBr) n:
3165, 1728, 1595 cm21. Anal. calcd. for C12H10N4O2S2: C, 47.04; H, 3.29;
N, 18.29. Found: C, 47.24; H, 3.30; N, 18.21.
Compound 3b. Yield: 98%. Yellow crystals. Mp: 241–2428C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 12.38 (s, 1H, NH), 7.39–7.02 (m, 4H, ArH),
5.59 (s, 2H, OCH2), 4.10 (s, 2H, SCH2). 13C NMR (100 MHz, DMSO-d6) d:
174.11, 171.46, 166.30, 163.46, 151.86, 130.12, 128.40, 123.45, 123.32,
116.59, 65.02, 35.76. MS: m/z 340 (16.5%, Mþ), 213 (100%). IR (KBr) n:
3121, 1726, 1603 cm21. Anal. calcd. for C12H9ClN4O2S2: C, 42.29; H, 2.66;
N, 16.44. Found: C, 42.09; H, 2.67; N, 16.52.
Compound 3c. Yield: 92%. Yellow crystals. Mp: 246–2488C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 12.35 (s, 1H, NH), 7.13–6.97 (m, 4H, ArH),
5.40 (s, 2H, OCH2), 4.11 (s, 2H, SCH2), 2.33 (s, 3H, CH3). 13C NMR
(100 MHz, DMSO-d6) d: 174.09, 171.44, 166.27, 163.54, 155.83, 130.47,
127.29, 125.72, 121.84, 115.03, 65.15, 35.74, 14.52. MS: m/z 320 (7%, Mþ),
213 (100%). IR (KBr) n: 3167, 1728, 1600 cm21. Anal. calcd. for
C13H12N4O2S2: C, 48.73; H, 3.78; N, 17.49. Found: C, 48.92; H, 3.77; N, 17.56.
Compound 3d. Yield: 92%. Yellow crystals. Mp: 242–2448C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 12.36 (s, 1H, NH), 7.02 (d, J ¼ 8 Hz, 2H,
ArH), 7.18 (d, J ¼ 8 Hz, 2H, ArH), 5.41 (s, 2H, OCH2), 4.11 (s, 2H,
SCH2), 2.34 (s, 3H, CH3). 13C NMR (100 MHz, DMSO-d6) d: 174.10,
171.47, 166.31, 163.52, 155.46, 131.87, 131.01, 114.76, 65.13, 35.75,
24.49. MS: m/z 320 (8%, Mþ), 213 (100%). IR (KBr) n: 3168, 1731,
1598 cm21. Anal. calcd. for C13H12N4O2S2: C, 48.73; H, 3.78; N, 17.49.
Found: C, 48.54; H, 3.79; N, 17.42.
1
Compound 3e. Yield: 97%. Yellow crystals. Mp: 247–2488C. H NMR
(400 MHz, DMSO-d6) d (ppm): 12.39 (s, 1H, NH), 7.23 (d, J ¼ 8.4 Hz, 2H,
ArH), 7.43 (d, J ¼ 8.4 Hz, 2H, ArH), 5.55 (s, 2H, OCH2), 4.10 (s, 2H,
SCH2). 13C NMR (100 MHz, DMSO-d6) d: 174.13, 171.49, 166.32, 163.42,
155.59, 129.95, 127.38, 116.52, 64.95, 35.78. MS: m/z 340 (18%, Mþ),
213 (100%). IR (KBr) n: 3125, 1721, 1602 cm21. Anal. calcd. for
C12H9ClN4O2S2: C, 42.29; H, 2.66; N, 16.44. Found: C, 42.48; H, 2.67; N,
16.51.

980
X.-C. Wang et al.
Compound 3f. Yield: 91%. Grey crystals. Mp: 207–2088C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 12.35 (s, 1H, NH), 6.99 (d, J ¼ 8 Hz, 2H,
ArH), 6.88 (d, J ¼ 8 Hz, 2H, ArH), 5.41 (s, 2H, OCH2), 4.10 (s, 2H,
SCH2), 3.70 (s, 3H, CH3). 13C NMR (100 MHz, DMSO-d6) d: 174.07,
171.43, 166.24, 163.61, 154.26, 151.31, 116.32, 114.81, 65.22, 55.47,
35.73. MS: m/z 336 (13%, Mþ), 213 (100%). IR (KBr) n: 3117, 1726,
1606 cm21. Anal. calcd. for C13H12N4O3S2: C, 46.42; H, 3.60; N, 16.66.
Found: C, 46.28; H, 3.61; N, 16.73.
Compound 3g. Yield: 92%. Yellow crystals. Mp: 202–2038C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 12.34 (s, 1H, NH), 6.91–6.83 (m, 4H,
ArH), 5.38 (s, 2H, OCH2), 4.10 (s, 2H, SCH2), 3.72 (s, 3H, CH3). 13C NMR
(100 MHz, DMSO-d6) d: 174.05, 171.39, 166.20, 163.64, 147.15, 147.07,
121.81, 114.28, 65.24, 55.82, 35.72. MS: m/z 336 (10%, Mþ), 213 (100%).
IR (KBr) n: 3120, 1724, 1605 cm21. Anal. calcd. for C13H12N4O3S2: C,
46.42; H, 3.60; N, 16.66. Found: C, 46.61; 3.59; N, 16.73.
Compound 3h. Yield: 88%. Yellow crystals. Mp: 217–2188C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 12.37 (s, 1H, NH), 7.13–6.81 (m, 4H,
ArH), 5.45 (s, 2H, OCH2), 4.10 (s, 2H, SCH2), 2.30 (s, 3H, CH3). 13C NMR
(100 MHz, DMSO-d6) d: 174.11, 171.49, 163.49, 166.33, 157.74, 140.13,
129.80, 122.08, 113.95, 112.12, 64.98, 35.77, 25.15. MS: m/z 320 (8%,
Mþ), 213 (100%). IR (KBr) n: 3164, 1729, 1597 cm21. Anal. calcd. for
C13H12N4O2S2: C, 48.73; H, 3.78; N, 17.49. Found: C, 48.96; H, 3.79; N,
17.41.
Compound 3i. Yield: 75%. Brown crystals. Mp: 252–2548C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 12.40 (s, 1H, NH), 7.35–6.99 (m, 4H, ArH),
5.60 (s, 2H, OCH2), 4.11 (s, 2H, SCH2). 13C NMR (100 MHz, DMSO-d6) d:
174.18, 171.72, 166.48, 162.52, 157.83, 150.42, 130.92, 121.35, 114.28,
110.54, 65.00, 35.80. MS: m/z 351 (12%, Mþ), 213 (100%). IR (KBr) n:
3134, 1735, 1577 cm21. Anal. calcd. for C12H9N5O4S2: C, 41.02; H, 2.58; N,
19.93. Found: C, 41.19; H, 2.57; N, 20.02.
Compound 3j. Yield: 79%. Grey crystals. Mp: 253–2558C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 12.39 (s, 1H, NH), 8.25 (d, J ¼ 8 Hz, 2H,
ArH), 7.30 (d, J ¼ 8 Hz, 2H, ArH), 5.66 (s, 2H, OCH2), 4.11 (s, 2H, SCH2).
13C NMR (100 MHz, DMSO-d6) d: 174.18, 171.85, 166.60, 162.61, 161.84,
141.73, 126.07, 115.71, 65.08, 35.80. MS: m/z 351 (15%, Mþ), 213 (100%).
IR (KBr) n: 3130, 1733, 1581 cm21. Anal. calcd. for C12H9N5O4S2: C,
41.02; H, 2.58; N, 19.93. Found: C, 41.20; H, 2.59; N, 20.01.
Compound 3k. Yield: 82%. Yellow crystals. Mp: 224–2268C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 12.36 (s, 1H, NH), 7.47–7.04 (m, 3H, ArH),

2-(5-Substituted-1,3,4-thiadiazolo-2-ylimino)-4-thiazolidinones
981
5.56 (s, 2H, OCH2), 4.10 (s, 2H, SCH2). 13C NMR (100 MHz, DMSO-d6) d:
174.10, 171.44, 166.30, 163.49, 150.05, 132.24, 128.58, 128.52, 124.76,
117.82, 65.19, 35.75. MS: m/z 375 (21%, Mþ), 213 (100%). IR (KBr) n:
3129, 1734, 1586 cm21. Anal. calcd. for C12H8Cl2N4O2S2: C, 38.41; H,
2.15; N, 14.93. Found: C, 38.58; H, 2.16; N, 14.86.
Compound 3l. Yield: 87%. Yellow crystals. Mp: 242–2438C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 12.38 (s, 1H, NH), 7.95–7.54 (m, 5H,
ArH), 4.13 (s, 2H, SCH2). 13C NMR (100 MHz, DMSO-d6) d: 185.53,
177.09, 174.13, 165.78, 131.21, 130.18, 129.57, 127.24, 35.86. MS: m/z
276 (31%, Mþ), 199 (100%). IR (KBr) n: 3111, 1726, 1583 cm21. Anal.
calcd. for C11H8N4OS2: C, 47.81; H, 2.92; N, 20.27. Found: C, 48.03; H,
2.93; N, 20.36.
1
Compound 3m. Yield: 87%. Yellow crystals. Mp: 222–2248C. H NMR
(400 MHz, DMSO-d6) d (ppm): 12.37 (s, 1H, NH), 7.45–7.18 (m, 4H,
ArH), 4.12 (s, 2H, SCH2). 13C NMR (100 MHz, DMSO-d6) d: 185.49,
177.05, 174.07, 165.90, 134.65, 132.94, 131.27, 130.12, 129.70, 127.56,
35.83. MS: m/z 310 (24%, Mþ), 199 (100%). IR (KBr) n: 3113, 1725,
1580 cm21. Anal. calcd. for C11H7ClN4OS2: C, 42.51; H, 2.27; N, 18.03.
Found: C, 42.31; H, 2.28; N, 18.11.
Compound 3n. Yield: 96%. Green crystals. Mp: 217–2188C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 12.36 (s, 1H, NH), 7.25–6.98 (m, 4H,
ArH), 4.12 (s, 2H, SCH2), 2.30 (s, 3H, CH3). 13C NMR (100 MHz, DMSO-
d6) d: 185.45, 177.02, 174.05, 165.96, 139.63, 131.37, 131.14, 130.07,
129.92, 124.25, 35.81, 25.10. MS: m/z 290 (45%, Mþ), 199 (100%). IR
(KBr) n: 3120, 1722, 1572 cm21. Anal. calcd. for C12H10N4OS2: C, 49.64;
H, 3.47; N, 19.30. Found: C, 49.86; H, 3.48; N, 19.22.
Compound 3o. Yield: 78%. Grey crystals. Mp: 255–2578C. 1H NMR
(400 MHz, DMSO-d6) d (ppm): 12.37 (s, 1H, NH), 8.45–7.60 (m, 4H,
ArH), 4.14 (s, 2H, SCH2). 13C NMR (100 MHz, DMSO-d6) d: 185.78,
177.40, 174.15, 166.01, 149.56, 133.15, 131.16, 131.14, 121.90, 121.82,
35.89. MS: m/z 321 (56%, Mþ), 199 (100%). IR (KBr) n: 3102, 1737,
1651 cm21. Anal. calcd. for C11H7N5O3S2: C, 41.12; H, 2.20; N, 21.79.
Found: C, 41.31; H, 2.19; N, 21.88.
ACKNOWLEDGMENT
We are thankful for the financial support from the Natural Science Foundation
of Gansu Province (3ZS061-A25-019) and the Scientific Research Fund of
Gansu Provincial Education Department (0601-25).

982
X.-C. Wang et al.
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