Some cyclization reactions with 2-ethoxycarbonylmethylidene-4,5-dihydro-4- thiazolinone

Article abstract of DOI:10.1080/10426500903061509

2-Ethoxycarbonylmethylidine-4,5-dihydro-4-thiazolinone (1) was condensed with bis aromatic aldehydes such as terephthalaldehyde or 4,4′-bisformyl- diphenylether (2a,b) (2:1 molar ratio) and furnished bis-4-thiaozlidinones (3a,b). The reaction of (3a,b) with malononitrile and aromatic aldehydes (1:2:2 molar ratio) gave bis thiazolopyridines (4a-d). Bis-(thiazolopyridine) derivative (6) was obtained by reaction of 4-thiaozlinone (5c) with bis aldehyde (2b) in refluxing ethanol containing piperidine. Cyclization of 4-thiazolinones (5a,b) with different α-cyanocinnamonitriles gave thiazolo[3,2-a] pyridines (7a-d). Compound 9 was produced via the reaction of 8 with thioglycolic acid, which reacted with p-chlorobenzaldehyde to produce 10. Compound 10 was condensed with hydrazine hydrate and afforded 11. Compounds 12 and 16a,b were produced by the reaction of 9 with isatin and α-ethoxycarbonylcinnamonitriles, respectively. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/10426500903061509

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Phosphorus, Sulfur, and Silicon and the
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Some Cyclization Reactions with 2-
Ethoxycarbonylmethylidene-4,5-
Dihydro-4-Thiazolinone
Y. A. Ammar a , Y. A. Mohamed a , G. A. M. El-Hagali a , A. S. Abd El-
Aal a & M. S. A. El-Gaby b
a Al-Azhar University , Nasr City , Cairo, Egypt
b Al-Azhar University at Assuit , Assuit, Egypt
Published online: 03 Jul 2010.
To cite this article: Y. A. Ammar , Y. A. Mohamed , G. A. M. El-Hagali , A. S. Abd El-Aal & M. S.
A. El-Gaby (2010) Some Cyclization Reactions with 2-Ethoxycarbonylmethylidene-4,5-Dihydro-4-
Thiazolinone, Phosphorus, Sulfur, and Silicon and the Related Elements, 185:7, 1386-1394, DOI:
10.1080/10426500903061509
To link to this article: http://dx.doi.org/10.1080/10426500903061509
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Phosphorus, Sulfur, and Silicon, 185:1386–1394, 2010
Copyright ꢀC Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500903061509
SOME CYCLIZATION REACTIONS WITH
2-ETHOXYCARBONYLMETHYLIDENE-4,5-DIHYDRO-4-
THIAZOLINONE
Y. A. Ammar,1 Y. A. Mohamed,1 G. A. M. El-Hagali,1
A. S. Abd El-Aal,1 and M. S. A. El-Gaby2
1Al-Azhar University, Nasr City, Cairo, Egypt
2Al-Azhar University at Assuit, Assuit, Egypt
2-Ethoxycarbonylmethylidine-4,5-dihydro-4-thiazolinone (1) was condensed with bis
aromatic aldehydes such as terephthalaldehyde or 4,4ꢀ-bisformyl-diphenylether (2a,b)
(2:1 molar ratio) and furnished bis-4-thiaozlidinones (3a,b). The reaction of (3a,b) with
malononitrile and aromatic aldehydes (1:2:2 molar ratio) gave bis thiazolopyridines
(4a–d). Bis-(thiazolopyridine) derivative (6) was obtained by reaction of 4-thiaozlinone
(5c) with bis aldehyde (2b) in refluxing ethanol containing piperidine. Cyclization of
4-thiazolinones (5a,b) with different α-cyanocinnamonitriles gave thiazolo[3,2-a]pyridines
(7a–d). Compound 9 was produced via the reaction of 8 with thioglycolic acid, which reacted
with p-chlorobenzaldehyde to produce 10. Compound 10 was condensed with hydrazine
hydrate and afforded 11. Compounds 12 and 16a,b were produced by the reaction of 9 with
isatin and α-ethoxycarbonylcinnamonitriles, respectively.
Keywords Bisthiazolidinone; bisthiazolo[3,2-a]pyridine derivatives; 4-thiazolidinone
INTRODUCTION
Some thiazolo[3,2-a]pyridines have been reported to possess various biological activ-
ities including antibacterial, anticancer, antihypertensive, antidilator, and funigicidal activ-
ities.1–8 A considerable number of bis heterocyclic compounds exhibited various biological
activities including antibacterial, fungicidal, tuberculostatic, and plant growth regulative
properties.9–12 It has also been reported that bis heterocyclic compounds display much
better antibacterial activity than heterocyclic compounds.13 We report in this article the
synthesis of some novel 4-thiazolidinone and bis thiazolo[3,2-a] pyridine derivatives.14–20
RESULTS AND DISCUSSION
It has been found that 4-thiazolinone (1) reacts with bis aromatic aldehydes (2a,b) in
refluxing ethanol to yield bis-4-thiazolinones (3a,b). The structure of compounds 3a,b was
confirmed by spectroscopic data.
1
The H NMR spectrum of 3a showed signals at δ 1.11 (t, 6H, 2CH3), 3.77 (q, 4H,
2CH2), 5.23 (s, 2H, 2CH-methylidene), 6.90–7.49 (m, 6H, Ar H + 2 benzylidene-H)
Received 15 February 2009; accepted 21 May 2009.
Address correspondence to G. A. M. El-Hagali, Al-Azhar University, Nasr City, Cairo, Egypt. E-mail:
Elhag1970@yahoo.com
1386

CYCLIZATION REACTIONS
1387
and 10.32, 10.40 (2s, 2H, 2NH). Ternary condensation of bis 4-thiazolinone (3a,b),
aromatic aldehydes, and malononitrile (1:2:2 molar ratio) afforded bisthiazolo pyridines
(4a–d). The structure of compounds 4a–d was in agreement with their spectral data. The
IR spectrum of 4a showed the presence of absorption bands for amino at 3406, 3350 cm−1
and cyano at 2190 cm−1 functional groups, and its mass spectrum showed a molecular ion
peak at m/z 849 (5.13%) and a base peak at m/z 55. 2-Ethoxycarbonylmethylidine-4,5-
dihydro-5-arylmethylidene-4-thiazolinones (5a–c) were produced via the condensation of
1 with aromatic aldehydes in refluxing ethanol containing catalytic amount of piperidine.
On the basis of elemental analysis and spectral data, the structure of thiazolidinone
derivatives 5a–c was confirmed. Mass spectrum of compound 5c (C16H18N2O3S) exhibited
a molecular ion peak at m/z 318 (6.67%) with a base peak at m/z 177 (14.22%).
Cyclization of 5a,b with different α-cyanocinnamonitriles gave thiazolopyridines
7a–d. 4,4ꢁ-Bis-(2,3,7-trihydro-3-oxo-5-amino-6-cyano-8-ethoxycarbonyl-7-aryl-1,3-thia-
zolo[3,2-a]pyridine-2-ylidenemethyl) diphenyl ether (6) was produced by the reaction of
5c, malononitrile, and bis aldehyde (2b) (2:2:1 molar ratio) in refluxing ethanol in the
presence of a catalytic amount of piperidine (Scheme 1).
The IR spectrum of 6 revealed absorption bands for cyano and amino groups at
1
2188, 3468, and 3410 cm−1. Its H NMR spectrum in (DMSO-d6) displayed a signals at
δ 1.04, 1.22 (2t, 6H, 2CH3-ester), 3.03, 3.11 (2s, 12H, 2N(CH3)2), 4.05, 4.99 (2q, 4H,
2CH2-ester), 5.57, 5.62 (2s, 2H, 2 pyridine-H), 6.87, 7.87 (m, 20H, Ar H+ benzylidene-H
+ 2NH2). The novel 4-thiazolinone (9) can not be obtained from the reaction of 1 with
4-chloroaniline under various conditions, thus compound 9 was produced from the reaction
of thioglycolic acid with N-(4-chlorophenyl)-2-cyano-acetamide 8 in acetic acid under
reflux conditions. Electrophiles such as p-chlorobenzaldehyde and isatin were condensed
with 9 and gave 4-thiazolidinone derivatives (10, 12). The mass spectrum of compound 10
(C25H15N2Cl3O2S) showed a molecular ion peak at m/z 513.5 (7.7%), and a base peak was
found in the spectrum at m/z 63. Also, the mass spectrum of compound 12(C19H12N3ClO3S)
displayed a molecular ion peak at m/z 397 (4.18%) and a base peak at m/z 127.
The reaction of thiazolidinone derivative 10 with hydrazine hydrate in refluxing
ethanol afforded pyrazolo[3,4-d]thiazole derivative 11 (Scheme 2).
Elemental analysis and spectral data were in complete accordance with pyrazolo[3,4-
d]thiazole derivative (11). Mass spectrum of compound 11(C25H16N4Cl3OS) exhibited a
molecular ion peak at m/z 525 (0.7%) and a base peak was found at m/z 127.
Finally, treatment of thiazolidinone derivative 9 with α-ethoxycarbonylcinnamoni-
triles in dioxane in the presence of a catalytic amount of piperidine gave the corresponding
thiazolo-[3,2-a]pyridine derivatives 16a,b (Scheme 3). The other possible structures 13a,b,
14a,b, and 15a,b were excluded on the basis of elemental analyses and spectral data. The
IR spectrum of compound 16b showed absorption bands at 3375, 3316, 2184, 1714, and
1650 cm−1 due to imino, hydroxy, cyano, and carbonyl functional groups, respectively. Its
1H NMR spectrum in (DMSO-d6) displayed signals at δ 5.05 (s, 1H, pyridine-H), 7.26–7.71
(m, 13H, Ar H + methylidene-H), 9.49 (s, 1H, NH), and 12.10 (br, 1H, OH).
EXPERIMENTAL
Melting points were recorded on a Fisher-Johns melting points apparatus and are
uncorrected. IR spectra were recorded on a Shimadzu 470 spectrometer using KBr pellets.
1H NMR spectra were recorded on a Varian Gemini spectrometer (200 MHz) using TMS
as internal standard and mass spectra on a Jeol-JMS-600 mass spectrometer. Elemental

1388
Y. A. AMMAR ET AL.
Ar
N
Ar
NC
CO2Et
EtO2C
S
CN
NH2
H2N
N
S
O
O
(X)
(4a-d)
ArCHO, CH2(CN)2
EtOH/pip.
CO2Et
EtO2C
NH
S
HN
O
S
O
(X)
(3a,b)
OHC
(X) CHO
, CH2(CN)2
(2a,b)
EtOH/pip.
O
3a
; X = zero,
3b; X = OC6H4-p
4a
H
N
EtO2C
; X = zero, Ar = C6H4Cl-p
4b; X = zero, Ar = C6H4OCH3-p
4c; X = OC6H4-p, , Ar = C6H4Cl-p
4d; X = OC6H4-p, Ar = C6H4OCH3-p
S
(1)
5a; Ar = C6H4CH3-4
5b; Ar = C6H4OCH3-4
5c; Ar = C6H4NMe2-4
ArCHO
EtOH/pip.
Ar
; Ar = C6H4CH3-4, Ar1 = C6H3(OH)(OCH3)-3,4
; Ar = C6H4CH3-4, Ar1 = C6H4OCH3-4
7a
7b
CN
CN
EtO2C
Ar1
S
O
HN
7c; Ar = C6H4OCH3-4, Ar1= C6H3(OH)(OCH3)-3,4
7d; Ar = C6H4OCH3-4, Ar1 = C6H4NMe2-4
Ar1
N
O
EtOH/pip.
EtO2C
S
Ar
NC
NH2
(5a-c)
(7a-d)
(5c)
, CH2(CN)2
CHO
OHC
O
EtOH/pip.
(2b)
CO2Et
EtO2C
S
S
N
O
N
NMe2
Me2N
O
O
H2N
CN
NC
NH2
(6)
Scheme 1
analyses were obtained from the Microanalytical Data Unit at Cairo University. The physical
and spectral data for the synthesized compounds are given in Tables I and II, respectively.
Compound 1 was prepared according to the reported method.21
1,4-Bis(2-ethoxycarbonylmethylidene-4-oxo-4,5-dihydro-5-yl)benzene
(3a), 4,4’-Bis(2-ethoxycarbonylmethylidene-4-oxo-4,5-dihydro-5-yl)diphenyl
Ether (3a,b)
To a solution of 1 (0.02 mol) in absolute ethanol (40 mL) containing a catalytic
amount of piperidine (0.5 mL), either a bisaldehyde 2a (0.01 mol) or 2b (0.01 mol) was

CYCLIZATION REACTIONS
1389
O
O
S
Ar
N
H
Ar
N
H
Cl
S
N
NH2NH2.H2O
EtOH
N
Cl
Cl
O
Cl
NH
N
(10)
(11)
Cl
CHO
O
dioxane/pip.
Ar
O
O
N
H
Ar
NHCOCH2CN
O
N
CH2COOH
SH
S
NH
O
H
N
H
S
NH
O
-H2O
O
N
Cl
H
(9)
(8)
(12)
CO2Et
Cl
NH2
HN
O
S
(1)
Scheme 2
added. The reaction mixture was heated under reflux for 6 h. The solid product formed was
collected by filtration.
1,4-Bis(2,3,7-trihydro-3-oxo-5-amino-6-cyano-7-aryl-8-ethoxycarbonyl-
1,3-thiazolo[3,2-a]pyridine-2-ylidenemethyl)-benzene (4a,b), 4,4ꢀ-Bis(2,3,7-
trihydro-3-oxo-5-amino-6-cyano-7-aryl-8-ethoxycarbonyl-1,3-thiazolo
[3,2-a]pyridine-2-ylidene-methyl)diphenyl Ether (4c,d)
To a solution of either 3a (0.01 mol) or 3b (0.01 mol) in absolute ethanol (40 mL)
containing a catalytic amount of piperidine (0.5 mL), malononitrile (0.02 mol) was added.
The reaction mixture was refluxed for 6 h. The solid product formed was collected by
filtration.
4,4ꢀ-Bis(2,3,7-trihydro-3-oxo-5-amino-6-cyano-7-aryl-8-ethoxycarbonyl-
1,3-thiazolo[3,2-a]pyridine-2-ylidene-methyl)-diphenyl Ether (6)
To a solution of 5c (0.02 mol) in absolute ethanol (40 mL) containing a catalytic
amount of piperidine (0.5 mL), malononitrile (0.02 mol) and 2b (0.01 mol) were added.
The reaction mixture was heated under reflux for 6h. The solid product formed was collected
by filtration.

1390
Y. A. AMMAR ET AL.
CONHAr
S
NH
O
Ar1
EtO2C
NH2
(13a,b)
O
Ar1
CO2Et
NH2
ArHN
N
O
S
O
S
CO2Et
CN
Ar
N
H
Ar1
(14a,b)
NH
O
EtOH/pip.
O
Ar1
CO2Et
NH2
ArHN
Ar1
(9)
Ar = C6H4Cl-4
N
S
O
(15a,b)
O
Ar1
CN
OH
ArHN
Ar1
N
S
O
(16a,b)
a; Ar1 = C6H4OCH3-4
b; Ar1 = C6H4Cl-4
Scheme 3
2-Ethoxycarbonylmethylidene-4-oxo-4,5-dihydro-5-arylmethylidene-
1,3-thiazole (5a–c)
Equimolar amounts of 4-thiazolinone 1 (0.01 mol) and aromatic aldehydes (0.01
mol) in absolute ethanol (40 mL) containing a catalytic amount of piperidine (0.5 mL) were
mixed together. The reaction mixture was heated under reflux for 3 h. The solid product
formed was collected by filtration.
2-Arylmethylidene-2–2,3,7-trihydro-3-oxo-5-amino-6-cyano-7-aryl-8-
ethoxycarbonyl-1,3-thiazolo[3,2-a]pyridine (7a–d)
Equimolar amounts of 4-thiazolinones 5a,b (0.01 mol) and α-cyanocinnamonitrile
derivatives (0.01 mol) in absolute ethanol (40 mL) containing catalytic amount of piperidine
(0.5 mL) were refluxed for 4 h. The solid product formed was collected by filtration.

1391

1392
Y. A. AMMAR ET AL.
Table II Physical and analytical data for the synthesized compounds
Elemental analyses
Calcd./found
Compd.
No.
Mp
(◦C)
Yield
(%)
Solvent
cryst.
Molecular formula
(Mol. Wt.)
C%
H%
N%
3a
3b
4a
4b
4c
4d
5a
5b
5c
6
211–213
191–193
271–273
281–283
225–227
235–237
180–182
195–197
192–194
271–273
225–227
228–230
241–243
235–237
235–237
292–294
>300
67
72
69
70
74
71
65
68
69
82
74
70
65
72
72
79
71
76
73
71
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
Bz∗
C22H20N2O6S2 (472)
55.93
55.95
59.57
59.55
59.36
59.46
62.85
62.87
61.21
61.23
57.02
57.03
62.28
62.21
59.01
59.00
60.37
60.40
65.13
65.10
61.34
61.30
65.46
65.46
61.78
61.78
64.54
64.53
49.16
49.16
58.53
58.93
57.08
57.11
57.35
57.35
62.99
62.95
57.88
57.93
4.23
4.25
4.25
4.20
3.53
3.50
4.28
4.30
3.61
3.61
3.16
3.16
5.19
5.20
4.91
4.50
5.66
5.65
4.80
4.70
4.70
4.71
4.86
4.85
4.55
4.55
5.17
5.17
7.07
7.06
2.92
2.92
3.04
3.01
3.01
2.97
3.84
3.86
2.75
2.77
5.93
5.97
4.96
4.96
9.89
9.90
10.00
10.05
8.92
8.91
8.31
8.33
4.84
4.85
4.59
4.60
8.80
8.81
11.69
11.60
8.58
8.59
8.87
8.86
8.31
8.33
11.15
11.15
10.42
10.40
5.46
5.76
10.05
10.00
10.56
10.60
7.34
7.37
7.23
7.25
C
C
28H24N2O7S2 (564)
42H30N6Cl2O6S2 (849)
C44H36N6O8S2 (840)
C
C
C
C
C
C
C
C
C
C
48H34N6Cl2O7S2 (941)
48H32N6Cl4O7S2 (1010)
15H15NO3S (289)
15H15NO4S (305)
16H18N2O3S (318)
52H46N8O7S2 (958)
26H23N3O5S (489)
26H23N3O4S (473)
26H23N3O6S (505)
27H26N4O4S (502)
7a
7b
7c
7d
9
C11H19N2ClO2S (268.5)
10
11
12
16a
16b
EtOH/Bz
EtOH/Bz
EtOH/Bz
EtOH
EtOH
C
C
C
C
C
25H15N2Cl3O2S (512.5)
25H16N4Cl3OS (525.5)
19H12N3ClO3S (397.5)
30H22N3ClO3S (571.5)
28H16N3Cl3O3S (580.5)
281–283
291–293
295–297
∗Bz = benzene.
2-N-(4-Chlorophenyl)acetamido-4-oxo-4,5-dihydro-1,3-thiazole (9)
To a solution of cyanoacetanilide derivative 8 (0.01 mol) in acetic acid (30 mL),
thioglycolic acid (0.01 mol) was added. The reaction mixture was heated under reflux for
3 h. The solid product formed was collected by filtration.

CYCLIZATION REACTIONS
1393
2-[5-(4-Chlorobenzylidene)-4-oxo-4,5-dihydro-1,3-thiazolo-2-yl]1,3-N-
bis(4-chlorophenyl)acrylamide (10)
To a solution of 9 (0.01 mol) in dioxane (30 mL) containing a catalytic amount of
piperidine (0.5 mL), p-chlorobenzaldehyde (0.01 mol) was added. The reaction mixture
was refluxed for 3 h. The solid product formed was collected by filtration.
1,3-N-Bis(4-chlorophenyl)-2-[3-(4-chlorophenyl)-1H-pyrazolo-[3,4-
d]thiazol-5-yl]acrylamide (11)
Equimolar amounts of 4-thiazolinone derivative 10 (0.01 mol) and hydrazine hydrate
(0.01 mol) in dioxane (30 mL) was refluxed for 6 h. The solid product formed was collected
by filtration.
N-(4-Chlorophenyl)-2-[4-oxo-5-(2-oxo-1,2-dihydro-indol-3-yli-
dene)thiazolidine]acetamide (12)
To a solution of 4-thiaozlidinone 9 (0.01 mol) in dioxane (30 mL) containing a
catalytic amount of piperidine (0.5 mL), isatin (0.01 mol) was added. The reaction mixture
was heated under reflux for 6 h. The solid product formed was collected by filtration.
2-(Arylmethylidene)-7-aryl-6-cyano-5-hydroxy-3-oxo-2,3-dihydro-7H-
thiazolo[3,2-a]pyridine-8-carboxylic Acid (4-Chloro-phenyl)
Amide (16a,b)
To a solution of compound 9 (0.01 mol) in dioxane (30 mL) containing a catalytic
amount of piperidine (0.5 mL), α-ethoxy-carbonylcinnamonitriles (0.01 mol) was added.
The reaction mixture was heated under reflux for 6 h. The solid product formed was
collected by filtration.
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