Synthesis and biological activity of mercaptobenzoxazole based thiazolidinones and their arylidenes

Article abstract of DOI:10.1002/jccs.200700144

Arylidenes of thiazolidines with mercaptobenzoxazole, namely[(aryl-4-oxo-1, 3-thiazolidin)-hydrazinoacetyl-mercaptobenxazole]; (5-arylidene)-2-aryl-4-oxo-1, 3-thiazoliden hydrazinoacetyl-mercaptobenxazole were synthesized. Their chemical structures have b

Full text of DOI:10.1002/jccs.200700144

Journal of the Chinese Chemical Society, 2007, 54, 1003-1010
1003
Synthesis and Biological Activity of Mercaptobenzoxazole Based
Thiazolidinones and Their Arylidenes
P. Kohli,* S. D. Srivastava and S. K. Srivastava
Synthetic Organic Chemistry Laboratory, Department of Chemistry, Dr. H. S. Gour University,
Sagar (M.P.) 470 003, India
Arylidenes of thiazolidines with mercaptobenzoxazole, namely[(aryl-4-oxo-1,3-thiazolidin)-hydra-
zinoacetyl-mercaptobenxazole]; (5-arylidene)-2-aryl-4-oxo-1,3-thiazoliden hydrazinoacetyl-mercapto-
benxazole were synthesized. Their chemical structures have been confirmed by 1H NMR, IR, mass spectra
and also by microanalytical data. Antimicrobial evaluation was done by agar dilution method against three
pathogenic bacteria viz. Bacillus subtilis, Escherichia coli and Klebsiella pneumoniae and three patho-
genic fungi viz. Aspergillus niger, Candida albicans and Fusarium oxysporum. Among new derivatives
evaluated, the chloro derivatives exhibited higher potency as compared to the standard drugs streptomycin
(for bacteria) and griseofulvin (for fungi) against the tested organisms.
Keywords: Thiazolidines; Mercaptobenzoxazole; Antimicrobial agent.
Scheme I
INTRODUCTION
Thiazolidinone moiety is well known for biological1-4
and pharmacological activities5-9 such as CNS stimulant
anthelmintic,10 antibacterial,11 antifungal,10,12 hypnotic,
amoebicidal13 mosquito repellant,14 analgesic,15,16 diurals,
antiinflammatory, anticonvulsant,17 nematocidal, antitu-
bercular,18 etc. 2-Mercaptobenzoxazole is also reported as
a good medicinal19 as well as a biological agent.20 These
findings focused particular interest on incorporatating
thiazolidinon-arylidenes and 2-mercaptobenzoxazole in
one framework with a view to obtain compounds of better
antimicrobial activity. It has been found that these two moi-
eties on incorporation enhance the biological activity.
For the synthesis of the target heterocycles the reac-
tion sequences outlined in Scheme I were followed. The re-
action of 2-mercaptobenzoxazole 1 with chloroacetyl chlo-
ride in methanol yielded 2-chloroacetyl mercaptobenzox-
azole 1. Compound 2 on condensation with different car-
bonyls afforded [2-(arylidinehydrazino acetyl) mercapto-
benzoxazoles] 3. These intermediate 3 on cycloaddition
with mercaptoacetic acid yielded thiazolidine derivatives,
(2-aryl-4-oxo-1,3-thiazolidin)-hydrazinoacetyl-mercapto-
benzoxazoles 4. The compound 4 on reaction with different
carbonyls in ethanol furnished [(5-aryliden)-1-aryl-4-oxo-
1,3-thiazolidin-hydrazinoacetyl-mercaptobenzoxazoles]
5. All the compounds synthesized were adequately charac-
terized by their elemental analyses, IR, 1H NMR and mass

1004 J. Chin. Chem. Soc., Vol. 54, No. 3, 2007
Kohli et al.
spectral data.
[(2-Hydrazinoacetyl)-mercaptobenzoxazole] (2)
To a solution of 1 (0.02 mole) and hydrazine hydrate
(0.02 mole) in methanol (30 mL) was kept at room temper-
ature for about 20 hours. The solvent was removed in vacuo
and the resulting solid was dried recrystallised from chloro-
form to produce analytical pure material: 70% of yield, mp
180-182 °C; IR (KBr) vmax cm-1: 3028, 1545, 1242, 1085,
1032, 643 (benzoxazole nucleus with aromatic ring), 3350,
RESULTS AND DISCUSSION
Biological Activity
Antimicrobial activity
The compounds 3a-j, 4a-j and 5a-z were screened for
their antibacterial activity against B. substilis, E. coli and
K. pnenumoniae and antifungal activity against A. niger, C.
albicans and F. oxysporum by agar dilution method at dif-
ferent concentrations (50 and 100 ppm) using acetone as
solvent. The plates were incubated at 37° for 24 h in the
case of antibacterial activity and 48 h in the case of anti-
fungal activity. The control was also maintained with 0.1
mL of acetone, and the zone of inhibition of the growth was
measured in mm. The activity was compared with the stan-
dard drugs. A commercial antibacterial Streptomycin (50,
100 mg/mL) and antifungal Griseofulvin (50, 100 mg/mL)
were also tested under similar conditions for comparison.
The results are presented in Tables 2 and 3.
1
3380 (-NHNH2), 1665 (C=O of amide), 1430 (CH2); H
NMR d 9.13 (s, br, 1H, NH), 7.02-7.95 (m, 4H, Ar-H), 4.53
(s, 2H, CH2), 4.40 (s, 2H, NH2), FAB-MS, m/z: 223 [M]+,
207, 195, 192, 178, 176, 164, 150, 131, 122, 118, 108, 92,
90, 79, 73, 66, 64, 65, 60. Anal. Calcd for C9H9N3O2S: C,
48.4; H, 4.0; N, 18.8. Found: C, 48.1; H, 3.89; N, 18.62.
2-(Aryliden-hydrazinoacetyl)-mercaptobenzoxazole
(3a)
A mixture of compound 2 (0.008 mole) and benzalde-
hyde (0.008 mole) and 2-3 drops of gl. acetic acid in etha-
nol (25 mL) was kept at room temperature for about 24
hours. The solvent was removed in vacuo and the resulting
solid was dried and recrystallised from chloroform : metha-
nol (5%, v/v) mixture to get compound 3a: 65% of yield,
mp 185-187 °C, IR (KBr) vmax cm-1: 3028, 1590, 1563,
1546, 1247, 1045, 650 (benzoxazole nucleus with aromatic
ring), 3342, 1339 (-NH), 1665 (C=O), 1622 (N=CH): 1H
NMR d 9.12 (s, br, 1H, NH), 7.00-7.90 (m, 4H, Ar-H), 4.95
(s, 1H, N = CHAr), 4.57 (s, 2H, CH2); FAB-MS, m/z: 311
[M]+, 293, 261, 234, 207, 192, 178, 164, 150, 133, 124,
122, 119, 118, 108, 92, 90, 79, 77, 66, 64. Anal Calcd for
C16H13N3O2S: C, 61.7; H, 4.18; N, 13.50. Found C, 61.2; H,
3.93; N, 13.28.
EXPERIMENTAL SECTION
Melting points were determined in open capillaries.
IR spectra were recorded on a Shimadzu 8416 FTIR (vmax in
cm-1), 1H NMR spectra on a Bruker DRX 300 in CDCl3 at
300 MHz using TMS as an internal standard and the mass
spectra on a Jeol SX-102 (FAB). Purity of compounds was
monitored by TLC on silica gel coated plates.
2-Chloroacetyl mercaptobenzoxazole (1)
Likewise other compounds 3b-3j were prepared in a
similar way using different carbonyls. Characterization
data are presented in Table 1.
An equimolar solution of 2-mercaptobenzoxazole
(0.06 mole) and chloroacetyl chloride (0.06 mole) in meth-
anol (30 mL) in the presence of anhydrous potassiumcar-
bonate (2 g) was kept at room temperature for about 25
hours. The solvent was removed in vacuo and the residue
was recrystallised from chloroform to furnish compound 1.
72% of yield, mp 180-182 °C; IR (KBr) vmax cm-1: 3020,
1582, 1565, 1540, 1245, 1080, 1030, 640 (benzoxazole nu-
cleus with aromatic ring), 1660 (C=O of amide), 1425
(CH2), 720 (C-S-C); 1H NMR d 7.07-7.98 (m, 4H, Ar-H),
4.55 (s, 2H, CH2); FAB-MS, m/z: 227 [M]+, 201, 192, 178,
174, 144, 119, 109, 92, 90, 60. Anal. calcd for C9H6NO2ClS:
C, 47.4; H, 2.6; N, 6.15. Found: C, 47.2; H, 3; N, 6.08.
[(2-aryl-4-oxo-1,3-thiazolidin)-hydrazinoacetyl
mercaptobenzoxazole] (4a)
To a mixture of 3a (0.0003 mole), mercaptoacetic
acid (0.0003 mole) was added in ethanol (30 mL) and kept
at room temperature for about 20 hours. The solvent was re-
moved in vacuo and the resulting solid was dried and
recrystallised from methanol to get 4a: 63% of yield, mp
190-192 °C; IR (KBr) vmax cm-1: 3030, 1588, 1560, 1550,
1240, 1039, 647 (benzoxazole nucleus with aromatic ring),
3340, 1336 (-NH-), 1717 (C=O cyclic), 2986 (N-CH-S),

Synthetic Organic Chemistry
J. Chin. Chem. Soc., Vol. 54, No. 3, 2007 1005
Table 1. Characterization data of compounds 3a-j, 4a-j and 5a-z
Found (Calcd)%
Compounds
Ar1
Ar2
Yield (%)
Mol. formula
C
H
N
3a
3b
3c
3d
3e
3f
C6H5
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
60
77
75
72
69
72
70
65
68
66
65
69
68
68
70
72
71
71
73
72
65
69
72
70
67
69
67
70
73
70
65
60
62
73
75
78
66
62
64
72
70
74
69
62
66
68
C16H13N3O2S
61.2(61.7)
55.3(55.5)
55.4(55.5)
55.0(55.5)
53.5(53.9)
53.7(53.9)
53.3(53.9)
59.5(59.8)
59.3(59.8)
59.6(59.8)
55.82(56.0)
51.3(51.8)
51.5(51.8)
51.6(51.8)
50.0(50.23)
50.10(50.23)
49.8(50.23)
54.4(54.9)
54.7(54.9)
54.3(54.9)
63.3(63.4)
58.8(59.1)
58.6(59.1)
58.7(59.1)
57.5(57.9)
57.3(57.9)
57.7(57.9)
61.8(62.0)
61.9(62.0)
61.9(62.0)
55.1(55.3)
55.0(55.3)
55.0(55.3)
54.0(54.2)
54.1(54.2)
53.8(54.2)
57.8(58.1)
57.7(58.1)
57.5(58.1)
53.0(53.2)
57.4(57.9)
56.4(56.8)
56.4(56.8)
61.8(62.0)
57.7(58.0)
58.13(58.42)
4.05(4.18)
3.28(3.47)
3.08(3.47)
3.19(3.47)
3.15(3.37)
3.30(3.37)
2.95(3.37)
4.2(4.3)
13.12(13.50)
11.8(12.1)
11.9(12.1)
12.0(12.1)
15.6(15.7)
15.3(15.7)
15.4(15.7)
13.7(14.0)
13.7(14.0)
13.9(14.0)
10.62(10.90)
9.80(10.08)
9.72(10.08)
9.90(10.08)
12.75(13.0)
12.90(13.0)
12.74(13.0)
10.0(10.12)
9.82(10.12)
9.73(10.12)
8.52(8.80)
8.0(8.2)
2-ClC6H4
3-ClC6H4
4-ClC6H4
2-NO2C6H4
3-NO2C6H4
4-NO2C6H4
2-OCH3C6H4
3-OCH3C6H4
4-OCH3C6H4
C6H5
C16H12N3O2SCl
C16H12N3O2SCl
C16H12N3O2SCl
C16H12N4O4S
C16H12N4O4S
3g
3h
3i
C16H12N4O4S
C17C15O3N3S
C17H15O3N3S
4.0(4.3)
3j
C17H15O3N3S
4.18(4.3)
3.35(3.80)
2.23(2.64)
2.32(2.64)
2.50(2.64)
3.12(3.25)
2.95(3.25)
2.88(3.25)
3.8(4.0)
4a
4b
4c
4d
4e
4f
C18H15N3O3S2
C18H11N3O3S2Cl
C18H11N3O3S2Cl
C18H11N3O3S2Cl
C18H14N4O5S2
C18H14N4O5S2
C18H14N4O5S2
C19H17N3O4S2
C19H17N3O4S2
C19H17N3O4
2-ClC6H4
3-ClC6H4
4-ClC6H4
2-NO2C6H4
3-NO2C6H4
4-NO2C6H4
2-OCH3C6H4
3-OCH3C6H4
4-OCH3C6H4
C6H5
4g
4h
4i
3.78(4.0)
3.85(4.0)
3.82(4.0)
3.3(3.5)
4j
5a
5b
5c
5d
5e
5f
C6H5
C25H19N3O3S2
C25H18N3O3S2Cl
C25H18N3O3S2Cl
C25H18N3O3S2Cl
C25H18N4O5S2
C25H18N4O5S2
C25H18N4O5S2
C26H21N3O4S2
C26H21N3O4S2
C26H21N3O4S2
C25H17N3O3S2Cl2
C25H17N3O3S2Cl2
C25H17N3O3S2Cl2
C25H17N4O5S2Cl
C25H17N4O5S2Cl
C25H17N4O5S2Cl
C26H20N3O4S2Cl
C26H20N3O4S2Cl
C26H20N3O4S2Cl
C25H17N5O7S2
C25H18N4S2O5
C26H20N4O6S2
C26H20N4O6S2
C26H211N3S2O4
C26H20N3O4S2Cl
C26H20N4O6S2
C6H5
2-ClC6H4
C6H5
3-ClC6H4
3.0(3.5)
7.8(8.2)
C6H5
4-ClC6H4
2.9(3.5)
7.9(8.2)
C6H5
2-NO2C6H4
3-NO2C6H4
4-NO2C6H4
2-OCH3C6H4
3-OCH3C6H4
4-OCH3C6H4
2-ClC6H4
3.27(3.47)
3.02(3.47)
3.13(3.47)
3.9(4.1)
10.4(10.8)
10.5(10.8)
10.3(10.8)
8.0(8.3)
C6H5
5g
5h
5i
C6H5
C6H5
C6H5
3.7(4.1)
8.2(8.3)
5j
C6H5
4.02(4.1)
3.02(3.13)
2.8(3.13)
2.7(3.13)
2.9(3.0)
7.8(8.3)
5k
5l
2-ClC6H4
2-ClC6H4
2-ClC6H4
2-ClC6H4
2-ClC6H4
2-ClC6H4
2-ClC6H4
2-ClC6H4
2-ClC6H4
2-NO2C6H4
2-NO2C6H4
2-NO2C6H4
2-OCH3C6H4
2-OCH3C6H4
2-OCH3C6H4
2-OCH3C6H4
7.3(7.7)
3-ClC6H4
7.4(7.7)
5m
5n
5o
5p
5q
5r
5s
5t
4-ClC6H4
7.5(7.7)
2-NO2C6H4
3-NO2C6H4
4-NO2C6H4
2-OCH3C6H4
3-OCH3C6H4
4-OCH3C6H4
2-NO2C6H4
C6H5
10.02(10.13)
9.8(10.13)
9.7(10.13
7.52(7.82)
7.63(7.82)
7.02(7.82)
12.2(12.4)
10.62(10.81)
10.02(10.20)
10.02(10.20)
8.13(8.30)
7.61(7.81)
7.43(7.86)
2.6(3.0)
2.8(3.0)
3.52(3.72)
3.60(3.72)
3.65(3.72)
2.72(3.0)
3.15(3.47)
3.32(3.64)
3.32(3.64)
4.02(4.17)
3.50(3.72)
3.32(3.74)
5u
5v
5w
5x
5y
5z
2-OCH3C6H4
2-OCH3C6H4
C6H5
2-ClC6H4
2-NO2C6H4
1422 (CH2), 718 (C-S-C); 1H NMR d 9.10 (s, br. 1H, NH),
7.10-7.9 (m, 9H, Ar-H) 4.50 (s, 2H, CH2), 4.48 (s, 2H CH2
cyclic), 3.18 (s, 1H, Ar-CH-N); FAB-MS, m/z: 385 [M]+,
343, 325, 311, 263, 207, 193, 192, 178, 165, 164, 162, 150,
136, 122, 118, 108, 92, 90, 79, 66, 64. Anal. Calcd for
C18H15N3O3S2: C, 56.0; H, 3.80; N, 10.9. Found: C, 56.0;

1006 J. Chin. Chem. Soc., Vol. 54, No. 3, 2007
Kohli et al.
Table 2. Antibacterial activity data of compounds 3a-j, 4a-j and 5a-z
B. subtilis
E. coli
K. pneunoniae
50 ppm 100 ppm
Compounds
50 ppm
100 ppm
50 ppm
100 ppm
3a
3b
3c
3d
3e
3f
-
+
+
++
++
+++
+++
++
++
+
-
+
+
++
+
+
+
++
+
++
+++
++
++
++
+
+
++
+
+
+
++
+
++
+
+
++
+
++
3g
3h
3i
+
+
++
+
+++
+
-
+
+
-
+
+
+
++
+
+
3j
+
++
++
++
+++
+++
++
+++
+++
++
+
+
+
+
++
4a
4b
4c
4d
4e
4f
+
+
++
+
++
++
+++
++
++
++
++
+
+++
+++
+++
++
++
++
+
+++
+++
+++
++
+++
++
+++
+
++
+++
+++
++
+++
+++
++
+
++
4g
4h
4i
++
+
+++
++
+
+
++
+
++
4j
+
++
+
+
+
+
++
5a
5b
5c
5d
5e
5F
5g
5h
5i
+
+
++
+
++
+
++
+
+
++
+
+
+
+
++
+
++
+
++
++
++
++
+
+
+
+
++
++
+
+
++
++
+
++
++
+
++
+
++
+
++
+
++
+
+
+
++
+
++
+
+
+
+
++
5j
+
+
++
+
+
5k
5l
+++
++
++
++
++
++
+
++++
+++
+++
+++
+++
++
++
+
+++
+++
+++
++
++
++
+
++++
++++
++++
+++
+++
+++
++
+++
++
+++
++
++
++
++
+
++++
+++
++++
+++
++
5m
5n
5o
5p
5q
5r
5s
++
++
+
+
++
++
+
+
+
++
+
++
5t
++
++
+
++
+++
++
++
++
+++
++
++++
++
++
++
++
++
++
+
+++
+++
++
++
++
++
+
+++
++
5u
5v
5w
5x
5y
5z
Sm
+++
++
+
++
+
++
+
++
++
+
+++
++
++
++
+++
+++
++
+++
+++
++++
++++
Sm = Streptomycin inhibition diameter in mm: (-) < 8, (+) 9-11, (++) 11-17, (+++) 17-23,
(++++) 23-28.

Synthetic Organic Chemistry
J. Chin. Chem. Soc., Vol. 54, No. 3, 2007 1007
Table 3. Antifungal activity data of compounds 3a-j, 4a-j and 5a-z
C. albicans F. oxysporum
50 ppm 100 ppm
A. nigar
Compounds
50 ppm
100 ppm
50 ppm
100 ppm
3a
3b
3c
3d
3e
3f
-
+
+
++
+
-
+
-
+
+
++
++
++
+
+
+
+
++
+
+
+
+
++
+
+
+
-
+
+
+
+
++
+++
+
++
+
+++
++
+
+
++
++
+
3g
3h
3i
++
-
+
+
-
-
+
-
+
+
+
3j
+
+
+
+
-
+
4a
4b
4c
4d
4e
4f
-
+
-
+
-
+
+
+
+
+
+
++
++
++
++
++
+++
+
+
++
+
+
++
++
++
+++
++
+
+
+
+
+
-
+
+
+
+
+
+
+
4g
4h
4i
+
+
+
+
-
-
-
-
+
+
-
+
-
+
4j
+
+
-
+
+
+
5a
5b
5c
5d
5e
5f
-
+
+
+
-
+
++
+
++
++
+++
++
++
++
+
++
++
+
+++
+++
++
++
++
++
++
++
++
+++
+++
+++
++
++
++
+
++
++
++
+
+++
+++
+++
++
++
++
++
++
++
++
+++
+++
++
++
+++
++
++
++
++
++
++
++
++
++
++
++++
++
+
+
++
+
+
+
5g
5h
5i
+
++
+
-
+
+
+
+
+
5j
+
++
+++
++
+++
++
++
+++
++
++
+
+
+
5k
5l
++
++
+++
+
++
++
+++
+
++
++
++
++
+
5m
5n
5o
5p
5q
5r
5s
++
++
+
+
++
+
++
+
+
+
++
+
+
+
+
+
5t
++
++
++
+
++
++
++
+
+
++
+++
+++
++
++
++
++
++++
++
+
5u
5v
5w
5x
5y
5z
GF
++
++
+
+
++
+
+
++
++
++
++++
+
++
++
++
+
++
+
++
+++
+++
GF = Griseofulvin inhibition diameter in mm: (-) < 8, (+) 8-11, (++) 11-17, (+++) 17-23,
(++++) 23-28.

1008 J. Chin. Chem. Soc., Vol. 54, No. 3, 2007
Chart 1 Mass fragmentation of the compound 5a
Kohli et al.

Synthetic Organic Chemistry
J. Chin. Chem. Soc., Vol. 54, No. 3, 2007 1009
H, 3.80; N, 10.9. Found: C, 55.82; H, 3.35; N, 10.62.
Other compounds 4b-j were prepared in a similar
way using 3b-j; characterization data are respectively pre-
sented in Table 1.
(C=O, cyclic), 1450 (CH2), 723 (C-S-C); 1H NMR d: 9.16
(s, 1H, NH), 7.38-7.89 (m, 8H, Ar-H), 4.59 (s, 2H, CH2),
4.62 (s, 2H, CH2, cyclic), 3.96 (s, 3H, OCH3), 3.26 (s, 1H,
N-CH-Ar).
[(5-Benzylidene)-2-aryl-4-oxo-1,3-thiazolidinhydrazino-
acetyl]-mercaptobenzoxazole 5a
[(5-Arylidene-2-chlorophenyl-4-oxo-1,3-thiazolidin)-
hydrazinoacetyl-mercaptobenzoxazole] (5b)
An equimolar solution of 4a (0.0002 mole) and benz-
aldehyde (0.0002 mole) in methanol (25 mL) was kept at
room temperature for about 24 hours. The solvent was re-
moved in vacuo and the residue was dried and recrystal-
lised from ethanol to afford pure material: 61% of yield, mp
185-187 °C; IR (KBr) vmax cm-1: 3342, 1590, 1545, 1239,
1040, 650 (benzoxazole nucleus with aromatic ring), 3348,
1342 (-NH), 2980 (N-CH-S), 1450 (CH2), 1715 (C=O cy-
clic), 1630 (> C=CH Ar), 721 (C-S-C); 1H NMR d 9.15 (s,
1H, NH), 7.04-7.96 (m, 14H, Ar-H), 5.15 (s, 1H > C=
CHAr), 4.48 (s, 2H, CH2) 3.20 (s, 1H, N-CH Ar). FAB-MS,
m/z: 473 [M]+, 445, 384, 343, 327, 295, 281, 267, 253, 207,
192, 178, 164, 162, 150, 136, 129, 122, 118, 108, 92, 90, 79,
66. The proposed mass fragmentation is cited in Chart 1.
Anal. Calcd for C25H19N3O3S2: C, 63.4; H, 4.0; N, 8.80.
Found: C, 63.3; H, 3.82; N, 8.52.
IR (KBr) vmax cm-1: 3340, 1592, 1550, 1239, 1042,
652 (benzoxazole nucleus with aromatic ring), 3350, 1345
(-NH), 2982 (N-CH-S), 1440 (CH2), 1718 (C=O, cyclic),
1632 (> C=CH Ar), 750 (Ar-Cl), 721 (C-S-C); 1H NMR d:
9.10 (s, 1H, NH), 7.00-7.92 (m, 13H, Ar-H), 5.12 (s, 1H, >
C=CH Ar), 4.51 (s, 2H, CH2), 325 (s, 1H, N-CH-Ar).
[(5-Arylidene-2-nitrophenyl-4-oxo-1,3-thiazolidin)-
hydrazinoacetyl-mercaptobenzoxazole] (5c)
IR (KBr) vmax cm-1: 3329, 1588, 1560, 1232, 1050,
660 (benzoxazole nucleus with aromatic ring), 3062, 1350
(-NH), 2988 (N-CH-S), 1490, 1350 (Ar-NO2), 1450 (CH2),
1721 (> C=O, cyclic), 1635 (> =CHAr), 718 (C-S-C); 1H
NMR d: 8.95 (s, 1H, -NH), 7.59-7.90 (m, 13H, Ar-H), 5.13
(s, 1H, > C=CH Ar), 4.55 (s, 2H, CH2), 3.29 (s, 1H, N-
CH-Ar).
[2-(2-Chlorophenyl-4-oxo-1,3-thiazolidin)-hydrazino-
acetyl-mercaptobenzoxazole] (4b)
[(5-Arylidene-2-methoxyphenyl-4-oxo-1,3-thiazolidin)-
hydrazinoacetyl-mercaptobenzoxazole] (5h)
IR (KBr) vmax cm-1: 3032, 1585, 1557, 1248, 1040,
645 (benzoxazole nucleus with aromatic ring) 3342, 1330
(-NH-), 2988 (N-CH-S), 1720 (C=O, cyclic), 1424 (CH2),
756 (Ar-Cl), 716 (C-S-C); 1H NMR d: 9.12 (s, 1H, NH),
7.02-7.90 (m, 8H, Ar + H), 4.55 (s, 2H, CH2), 4.50 (s, 2H,
CH2, cyclic), 3.17 (s, 1H, CH-Ar).
IR (KBr) vmax cm-1: 3320, 1590, 1564, 1237, 1047,
652 (benoxazole nucleus with aromatic ring) 3066, 1352
(-NH), 2983 (N-CH-S), 1453 (CH2), 1716 (> C=O, cyclic),
1632 (> C=CH Ar), 2872, 1162 (Ar-OCH3), 721 (C-S-C);
1H NMR d: 9.02 (s, 1H, NH), 7.58-7.92 (m, 13H, Ar-H),
5.09 (s, 1H, > C=CH Ar), 4.49 (s, 2H, CH2), 3.31 (s, 1H,
N-CH-Ar), 3.90 (s, 3H, OCH3).
[2-(2-Nitrophenyl-4-oxo-1,3-thiazolidin)-hydrazinoace-
tyl-mercaptobenzoxazole] (4c)
IR (KBr) vmax cm-1: 3035, 1577, 1562, 1237, 1048,
650 (benzoxazole nucleus with aromatic ring) 3420-1350
(-NH), 2985 (N-CH-5) 1712 (> C=O, cyclic), 1429 (CH2),
1495, 1345 (Ar-NO2), 720 (C-S-C); 1HNMR d: 9.14 (s, 1H,
NH), 7.32-7.82 (m, 8H, Ar-H), 4.52 (s, 2H, CH2), 4.49 (s,
2H, CH2 (cyclic), 3.20 (s, 1H, CH-Ar).
ACKNOWLEDGEMENTS
The authors are thankful to SAIF, CDRI, Lucknow,
for providing special and analytical data of the compounds.
Authors are also thankful to the Head of the Botany Depart-
ment and the Head of the Microbiology Department of Dr.
H. S. Gour University, Sagar, for giving cooperation for bi-
ological screening.
[2-(2-Methoxyphenyl-4-oxo-1,3-thiazolidin)-hydrazino-
acetyl-mercaptobenzoxazole] (4h)
IR (KBr) vmax cm-1: 3038, 1579, 1565, 1243, 1055,
642 (benzoxazole nucleus with aromatic ring), 3358, 1348
(-NH), 2867, 1172 (Ar-OCH3), 2992 (N-CH-S), 1715
Received June 6, 2006.

1010 J. Chin. Chem. Soc., Vol. 54, No. 3, 2007
Kohli et al.
Chem. Soc. 2004, 81, 342-343.
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