The synthesis of some pyrazolyl- and thiazolylthienopyridines

Article abstract of DOI:10.1080/10426500600605665

2-acetyl-3-amino-4,6-dimethylthieno[2,3-b]pyridine 1 reacted with dimethoxy-tetrahydrofuran in acetic acid and ethyl cyanoacetate in the presence of ammonium acetate or with NaNO 2 in the presence of an AcOH/HCl mixture to produce 2-4. Compound 2 reacted

Full text of DOI:10.1080/10426500600605665

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The Synthesis of
Some Pyrazolyl- and
Thiazolylthienopyridines
A. M. Kamal El-Dean a , A. A. Geies a & Y. A. El-
Ossaily a
a Chemistry Department, Assiut University, Assiut,
Egypt
Published online: 21 Sep 2006.
To cite this article: A. M. Kamal El-Dean , A. A. Geies & Y. A. El-Ossaily
(2006) The Synthesis of Some Pyrazolyl- and Thiazolylthienopyridines,
Phosphorus, Sulfur, and Silicon and the Related Elements, 181:9, 2013-2022, DOI:
10.1080/10426500600605665
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Phosphorus, Sulfur, and Silicon, 181:2013–2022, 2006
Copyright © Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500600605665
The Synthesis of Some Pyrazolyl-
and Thiazolylthienopyridines
A. M. Kamal El-Dean
A. A. Geies
Y. A. El-Ossaily
Chemistry Department, Assiut University, Assiut, Egypt
2-acetyl-3-amino-4,6-dimethylthieno[2,3-b]pyridine
1 reacted with dimethoxy-
tetrahydrofuran in acetic acid and ethyl cyanoacetate in the presence of ammo-
nium acetate or with NaNO in the presence of an AcOH/HCl mixture to produce
2
2–4. Compound 2 reacted with aromatic aldehydes, semicarbazide hydrochloride,
thiosemicarbazide, and phenyl hydrazine or with hydrazine hydrate to give com-
pounds 5a–c and 11a–d, respectively.
Chalcone 5 reacted with hydrazines, hydroxylamine hydrochloride, or thiourea
to produce compounds 6–9. Thiosemicarbazone 11b reacted with α-haloester to
produce the corresponding thiazolidinone derivatives 12a,b; also it reacted with
ω-bromoacetophenone to give thiazoline derivatives 13a,b.
Keywords Pyrrolylthiazolylthienopyridines; pyrrolylthienopyridines; thienopyridines
INTRODUCTION
Thieno[2,3-b]pyridines are useful for multiple pharmacological applica-
tions. Thus, dihydrothieno[2,3-b]pyridine shows remarkable effects as a
calcium antagonist1 and has been also used in the treatment of epilepsy,
Alzheimer’s disease, and Huntington’s corea.2 Some thieno[2,3-b]
pyridines have shown interesting as an antiatherosclerotic,3 and other
thienopyridines show antimicrobial effects.4
In view of the previously discussed benefits and in continuation of
our work with thienopyridines,3−5 herein in this article we report the
synthesis of some new thienopyridines.
Received October 1, 2005; accepted November 25, 2005.
Address correspondence to A. M. Kamal El-Dean, Assiut University, Chemistry
Department, Faculty of Science, Assiut 71516, Egypt. E-mail: a.eldean@acc.aun.edu.eg
2013

2014
A. M. K. El-Dean et al.
RESULTS AND DISCUSSION
2-acetyl-3-amino-4,6-dimethylthieno[2,3-b]pyridine6 1 reacted with
dimethoxy-tetrahydrofuran in acetic acid, ethyl cyanoacetate in am-
monium acetate, and sod. Nitrite in acetic acid/HCl mixture to pro-
duce 2-acetyl-3(1-pyrrolyl)-4,6-dimethylthieno[2,3-b]pyridine 2, pyri-
dothienopyridine 3, and pyridothienopyridazine 4, respectively.
SCHEME 1
Compound 2 reacted with aromatic aldehydes in alcoholic NaOH
(10%) to produce the corresponding substituted benzalacetyl derivative
5. The produced chalcone reacted with hydrazine hydrate in acetic acid
to give a pyrazolinyl derivative, which spontaneously oxidized under
the reaction condition and lost 2H, followed by acylation to give 6a,b.
Another pyrazolyl derivatives 7a,b was produced by the same manner
by refluxing compound 5 with phenyl hydrazine in ethanol.
Also, when compounds 5a–c were allowed to react with hydroxy-
lamine hydrochloride in ethanol in the presence of sodium acetate, isox-
azolyl derivatives 8a–c were obtained.
The pyrimidine derivative 9 was synthesized by the reaction of chal-
cone 5a with thiourea in ethanol in the presence of sodium ethoxide,
while the dihydropyrimidine derivative was produced, followed by de-
hydrogenation under the reaction condition. When chalcone compound
5 was allowed to react with malononitrile in ethanol in the presence of
catalytic amount of piperidine, pyrano derivative 10 was obtained.
Compound 2 was condensed with amino compounds, namely semi-
carbazide hydrochloride in ethanol in the presence of sodium acetate,
thiosemicarbazide in acetic acid, phenyl hydrazine in ethanol, or with
hydrazine hydrat in ethanol, to give compounds 11a–d.

Pyrazolyl- and Thiazolylthienopyridines
2015
SCHEME 2
Thiosemicarbazone 11b reacted with α-halocompounds, such as α-
haloester (2-ethyl chloroacetate, α-bromomethylpropionate), to give thi-
azolidinone derivatives 12a,b. Also, when compound 11b was allowed to
react with ω-bromoacetophenones to give thiazoline derivatives 13a,b.
EXPERIMENTAL
Melting points were determined on a Kofler melting point apparatus
and are uncorrected. IR spectra were recorded on potassium bromide
disks on a Pye Unicam spectrophotometer using the KBr Wafer tech-
nique. 1H NMR spectra were obtained on Varian 390 90-MHz spectrom-
eter in a suitable deuterated solvent. Chemical shifts were determined
on the δ scale by using tetramethylsilan as the internal standard. Ele-
mental analyses were obtained on Perkin Elmer 240 C microanalyzer.
2-Acetyl-3-amino-4,6-dimethylthieno[2,3-b]pyridine (1)
Prepared according to the literature method; m.p. 207◦C; Lit.[9] m.p.
206–207◦C.

2016
A. M. K. El-Dean et al.
SCHEME 3
2-Acetyl-3(1-pyrrolyl)-4,6-dimethylthieno[2,3-b]pyridine (2)
A mixture of compound 1 (2.23 g, 0.01 mol) and dimethoxytetrahydro-
furan (0.01 mol) in acetic acid (20 mL) was heated under reflux for one
h, allowed to cool, and poured into cold water. The solid product was
collected and washed with Na2CO3 (10% solution) several times and
recrystallized from ethanol as white crystals, 2.00 gm, 74% yield, m.p.
207◦C.
Anal. calcd. for C15H14N2OS(270.36): C, 66.64; H, 5.22; N, 10.36; S,
11.86%. Found: C, 66.46; H, 5.55; N, 10.14; S, 11.88%. IR: ν = 1700 cm−1
(C O) and showed the disappearance of band characteristic of NH2
1
group in the starting material. HNMR(CDCl3): δ = 1.85, 2.2, 2.7 (3s,
9H, CH3), 6.2–6.4, 6.55–6.75 (2m, 4H, 4CH-pyrrolyl ring), 6.9 (s, 1H,
CH-pyridine).
3-Cyano-4,7,9-trimethylpyrido[3’.2’:2,3]thieno[5,4-b]pyridin-
1(2H)-one (3)
A mixture of compound 1 (2.23 gm, 0.01 mol), ethyl cyanoacetate, and
ammonium acetate (10 g) was heated under reflux for 2 h; then ethanol
(30 mL) was added and refluxed for an additional 2 h. The solid product
was filtered off in hot, washed well with ethanol, and recrystallized
from dioxan as yellow crystals, 1.7 gm, 62% yield, m.p. > 300◦C.
Anal. calcd. for C14H11N3OS(269.33): C, 62.44; H, 4.12; N, 15.60; S,
11.91% Found: C, 62.18; H, 3.88; N, 15.44; S, 12.13%. IR: ν = 3250 cm−1
1
(NH), 1675 cm−1 (C O). HNMR(CF3CO2D): δ = 2.1, 2.5, 2.9 (3s, 9H,
3CH3), 6.9 (s, 1H, CH-pyridine).

Pyrazolyl- and Thiazolylthienopyridines
2017
1,4-Dihydro-8,9-dimethylpyrido[2,3:5’,4’]thieno[2,3-
c]pyridazin-4-one (4)
To a stirred ice cooled solution of compound 1 (1.1 gm, 0.005 mol) in
a mixture of HCl (2 mL, 11 N), and acetic acid (5 mL), sodium nitrite
solution (0.01 mol in 3 mL of H2O) was added dropwise for 10 min.
The stirring was continued for 30 min and then allowed to stand for 2
h. The solid product was collected and recrystallized from ethanol as
yellow crystals, 0.77 gm, 67% yield, m.p. 289◦C.
Anal. calcd. for C11H9N3OS(231.28): C, 57.13; H, 3.92; N, 18.17; S,
13.86%. Found: C, 56.88; H, 4. 21; N, 18.00; S, 14.07%. IR: ν = 3340 cm−1
1
(NH) and 1670 cm−1 (CO). HNMR (DMSO-d6): δ = 2.4, 2.8 (2s, 6H,
2CH3), 6.95 (s, 1H, CH-pyridine), 7.6 (s, 1H, CH-pyridazine), and 9.9 (s,
1H, NH).
2-Arylideneacetyl-3(pyrrol-1yl)-4,6-dimethylthieno[2,3-
b]pyridine (5a–c)
A mixture of compound 2 (2.7 gm, 0.01 mol) and aromatic aldehyde
(0.01 mol) in alcholic NaOH solution (10%, 30 mL) was stirried for
5 h.The solid product was collected and washed well with water and
recrystallized from acetic acid. Physical constants and spectral data of
compounds 5a–c are listed in Tables I and II.
4,6-Dimethyl-3(pyrrol-1-yl)-2(2-acetyl-3-diaryl-pyrazolin-
5yl)thieno[2,3-b]pyridine (6)
A mixture of chalcone compounds 5a–c (0.01 mol) and hydrazine hy-
drate (0.01 mol) in acetic acid (20 mL) was heated under reflux for 4
h, allowed to cool, and then poured into cold water (100 mL). The solid
product was collected and recrystallized from ethanol. Physical con-
stants and spectral data of compounds 4a,b are listed in Tables I and
II.
4,6-Dimethyl-3(pyrrol-1-yl)-2(2,3-diaryl-pyrazolin-5-
yl)thieno[2,3-b]pyridine (7)
A mixture of chalcone compound 5 (0.01 mol) and phenyl hydrazine
(0.01 mol) in ethanol (25 mL) was heated under reflux for 5 h and then
allowed to cool. The solid product was collected and recrystallized from
ethanol. Physical constants and spectral data of compounds 7a–c are
listed in Tables I and II.

2018
A. M. K. El-Dean et al.
TABLE I Physical Constants and Analytical Data of compounds 5a–c
Analytical data (calcd./found)
M.P.
◦C
Yield
%
Molecular
formula
No.
5a
C
H
N
S
252
220
75
72
68
60
64
71
67
74
77
63
67
71
65
69
72
75
C22H18N2OS
(358.46)
C23H20N2O2S
(388.48)
22H17N3O3S
(403.46)
73.72
73.95
71.11
70.87
65.49
65.63
69.88
69.66
67.85
67.94
63.01
63.01
75.31
75.20
73.08
72.88
68.42
68.19
71.14
70.93
68.81
68.67
63.45
63.24
56.38
55.16
57.41
57.57
64.98
64.65
60.30
60.70
5.06
4.86
5.19
4.99
4.25
4.03
4.89
5.12
5.01
4.78
4.19
4.19
4.97
5.19
5.08
5.32
4.31
4.53
4.61
4.89
4.77
5.0
3.87
4.04
4.474
.21
4.82
4.72
4.77
4.70
4.22
4.12
7.81
8.03
7.21
8.94
9.18
8.25
8.03
7.95
8.15
7.77
7.91
7.23
7.15
7.01
7.01
7.18
6.92
6.73
6.50
6.52
6.32
8.63
8.59
7.99
8.18
7.70
7.66
16.72
16.57
16.13
16.37
14.46
14.44
13.41
13.58
5b
5c
7.47
285–287
212
C
10.42
10.13
13.58
13.36
12.66
12.45
15.31
15.31
12.55
12.49
11.76
11.54
14.25
14.08
11.31
11.21
10.47
10.33
13.45
13.52
18.261
8.19
6a
C
24H20N4OS
(412.52)
6b
232
C
C
25H22N4O2S
(442.54)
24H19N5O3S
(457.51)
C28H22N4S
(446.58)
6c
289
7a
254
7b
235
C
29H24N4OS
(476.60)
7c
310
C
28H21N5O2S
(491.58)
8a
210
C
22H17N3OS
(371.46)
8b
225
C
C
23H19N3O2S
(401.49)
22H16N4O3S
(416.46)
C18H17N5OS2
(383.50)
C19H19N5OS2
(397.52)
8c
241
12a
12b
13a
13b*
237
233
17.62
17.82
15.79
15.98
14.65
14.85
289
C
24H21N5S2
(443.60)
299
C
24H20ClN5S2
(478.04)
*Calcd, Cl = 7.42; Found = 7.65.
4,6-Dimethyl-3(pyrrol-1-yl)-2(5-aryl-[1,2]oxzazolin-3-
yl)thieno[2,3-b]pyridine (8)
A mixture of chalcone compound 5 (0.01 mol), sod. acetate (0.015 mol),
and hydroxylamine hydrochloride (0.01 mol) in ethanol (25 mL) was
heated under reflux for 5 h, allowed to cool, and then poured into cold
water. The solid product was collected and recrystallized from ethanol.
Physical constants and spectral data of compounds 8a–c are listed in
Tables I and II.

Pyrazolyl- and Thiazolylthienopyridines
2019
TABLE II Spectral Data of Compounds 5a–c
No.
5a
IR
1HNMR
1705 cm−1 (C O), 1600
cm−1 (C C)
(CDCl3): 1.9, 2.5 (2s, 6H, 2CH3), 6.2–6.4,
6.55–6.75 (2m, 4H, 4CH-pyrrolyl ring), 6.85
(s, 1H, CH-pyridine) and 7.0–7.8 (m, 7H,
CH CH , Ar-H)
(CDCl3): 1.9, 2.5, 3.8 (3s, 9H, 3CH3), 6.2–6.4,
6.55–6.75(2m, 4H, 4CH-pyrrolyl ring), 6.9 (s,
1H, CH-pyridine) and 7.0–7.8 (m, 6H,
CH CH , Ar-H)
(CDCl3): 1.9, 2.5, 3.2 (3s, 9H, 3CH3), 6.2–6.4,
6.55–6.75 (2m, 4H, 4CH-pyrrolyl ring), 6.9 (s,
1H, CH-pyridine) and 7.0–7.8 (m, 6H,
CH CH , Ar-H)
2.2, 2.4, 2.8 (3s, 9H, 3CH3), 6.4 (s, 1H, CH
pyrazole), 6.1–6.4, 6.55–6.75 (2m, 4H,
4CH-pyrrolyl ring), 7.05 (s, 1H, CH-pyridine)
and 7.3–7.7 (m, 5H, Ar-H)
2.2, 2.4, 2.8, 3.9 (4s, 12H, 4CH3), 6.4 (s, 1H, CH
pyrazole), 6.2–6.4, 6.55–6.75 (2m, 4H,
4CH-pyrrolyl ring), 7.1 (s, 1H, CH-pyridine)
and 7.2, 7.6 (2d, 4H, Ar-H)
2.2, 2.4, 2.9 (3s, 9H, 3CH3), 6.5 (s, 1H, CH
pyrazole), 6.2–6.4, 6.55–6.75 (2m, 4H,
4CH-pyrrolyl ring), 7.1 (s, 1H, CH-pyridine)
and 7.6, 8.2 (2d, 4H, Ar-H)
1.9, 2.5 (2s, 6H, 2CH3), 6.5 (s, 1H, CH pyrazole),
6.2–6.4, 6.55–6.75 (2m, 4H, 4CH-pyrrolyl
ring), 6.9 (s, 1H, CH-pyridine) and 7.0–7.8 (m,
10H, Ar-H)
1.9, 2.5, 3.9 (3s, 9H, 3CH3), 6.5 (s, 1H, CH
pyrazole), 6.2–6.4, 6.55–6.75 (2m, 4H,
4CH-pyrrolyl ring), 6.9 (s, 1H, CH-pyridine)
and 7.0–7.8 (m, 9H, Ar-H)
2.3, 2.6(2s, 6H, 2CH3), 6.5 (s, 1H, CH pyrazole),
6.2–6.4, 6.55–6.75 (2m, 4H, 4CH-pyrrolyl
ring), 6.9 (s, 1H, CH-pyridine) and 7.0–7.8 (m,
9H, Ar-H)
DMSO-d6: 2.35, 2.7(2s, 6H, 2CH3), 6.1 (s, 1H,
CH oxazole); 6.2–6.4, 6.55–6.75 (2m, 4H,
4CH-pyrrolyl ring), 6.9 (s, 1H, CH-pyridine)
and 7.0–7.8 (m, 5H, Ar-H)
DMSO-d6: 2.3, 2.7(2s, 6H, 2CH3), 3.7 (s, 3H,
CH3), 6.1 (s, 1H, CH oxazole); 6.2–6.4,
6.55–6.75 (2m, 4H, 4CH-pyrrolyl ring), 7.0 (s,
1H, CH-pyridine) and 7.1–7.3 (2d, 4H, Ar-H)
DMSO-d6: 2.4, 2.75(2s, 6H, 2CH3), 6.1 (s, 1H,
CH oxazole); 6.3–6.4, 6.6–6.8 (2m, 4H,
4CH-pyrrolyl ring), 7.05 (s, 1H, CH-pyridine)
and 7.2, 7.8 (2d, 4H, Ar-H)
5b
5c
6a
6b
6c
7a
7b
7c
8a
8b
8c
1705 cm−1 (C O), 1600
cm−1 (C C)
1710 cm−1 (C O), 1600
cm−1 (C C)
1690 cm−1 (C O), 1610
cm−1 (C N)
1690 cm−1 (C O), 1600
cm−1 (C N)
1690 cm−1 (C O), 1610
cm−1 (C N)
3050 cm−1 (CH-aromatic),
1620 cm−1 (C N)
3050 cm−1 (CH-aromatic),
1620 cm−1 (C N)
3050 cm−1 (CH-aromatic),
1630 cm−1 (C N)
3050 cm−1 (CH-aromatic),
1630 cm−1 (C N)
3050 cm−1 (CH-aromatic),
1630 cm−1 (C N)
3050 cm−1 (CH-aromatic),
1630 cm−1 (C N)
(Continued on next page)

2020
A. M. K. El-Dean et al.
TABLE II Spectral Data of Compounds 5a–c (Continued)
No.
12a
IR
1HNMR
3350 cm−1(NH), 3050 cm−1
(CH-aromatic), 1720 cm−1
(CO), 1630 cm−1 (C N)
DMSO-d6: 1.9, 2.5, 3.3 (3s, 9H, 3CH3), 4.2 (s,
2H, CH2), 6.2–6.4, 6.55–6.75 (2m, 4H,
4CH-pyrrolyl ring), 6.9 (s, 1H, CH-pyridine)
and 10.2 (s, 1H, NH)
DMSO-d6: 1.9, 2.5, 3.3 (3s, 9H, 3CH3), 2.8 (d,
3H, CH3), 4.2 (q, 1H, CH), 6.2–6.4, 6.55–6.75
(2m, 4H, 4CH-pyrrolyl ring), 6.9 (s, 1H,
CH-pyridine) and 10.2 (s, 1H, NH)
DMSO-d6: 1.9, 2.5, 3.3 (3s, 9H, 3CH3), 6.2–6.4,
6.55–6.75 (2m, 4H, 4CH-pyrrolyl ring), 6.9 (s,
1H, CH-pyridine) and 7.0-7.8 (m, 6H, Ar-H,
CH thiazol)
DMSO-d6: 1.9, 2.5, 3.3 (3s, 9H, 3CH3), 6.2–6.4,
6.55–6.75 (2m, 4H, 4CH-pyrrolyl ring), 6.9 (s,
1H, CH-pyridine) and 7.2, 7.8 (2d, 4H Ar-H),
7.0 (s, 1H, CH thiazol)
12b
13a
13b
3320 cm−1(NH), 1720 cm−1
(CO), 1630 cm−1 (C N)
3360 cm−1(NH), 1610 cm−1
(C N)
3340 cm−1(NH), 1620 cm−1
(C=N)
6-Aryl-4-[4,6-Dimethyl-3(pyrrol-1-yl)thieno[2,3-b]pyridine-2-
yl]pyrimidin-2(1H)-thione (9)
A mixture of chalcone compound 5a (3.58 gm, 0.01 mol) and thiourea
(0.01 mol) in absolute ethanol (25 mL) containing sod. ethoxide (0.01
mol) was heated under reflux for 6 h, allowed to cool, and poured into
cold water. The produced solution was acidified with HCl (0.1 N) to just
pH 7. The solid product was collected and recrystallized from dioxane
as yellow crystals, 2.6 gm, 63% yield, m.p. > 300◦C.
Anal. calcd. for C23H18N4S2(414.55): C, 66.64; H, 4.38; N; 13.51, S,
15.47%. Found: C, 66.83; H, 4.54; N; 13.32, S, 15.63%. IR: ν = 3340 cm−1
(NH) and 1620 cm−1 (C N ). 1HNMR(DMSO-d6): δ = 2.4, 2.7 (2s, 6H,
2CH3), 6.2, 6.8(2d, 4H, CH-pyrryl), 7.05 (s, 1H, CH-pyridine), 7.3–
7.8 (m, 5H, CH-aromatic), 8.1 (s, 1H, CH-pyrimidine) and 11.9 (s, 1H,
NH).
4,6-Dimethyl-2-[2-amino-3-cyano-4(H)-4phenylpyran-6-yl]-3-
(pyrrol-1yl)thieno[2,3-b]pyridine (10)
To a mixture of chalcone compound 5a (3.58 gm, 0.01 mol) and malonon-
itrile (0.01 mol) in absolute ethanol (25 mL), a few drops of piperidine
were added. The mixture was heated under reflux for 5 h, allowed to
cool, and poured into cold water. The solid product was collected and
recrystallized from dioxane as yellowish white crystals, 2.8 gm, 66%
yield, m.p. > 300◦C.

Pyrazolyl- and Thiazolylthienopyridines
2021
Anal. calcd. for C25H20N4OS(424.53): C, 70.73; H, 4.75; N, 13.20;
S, 7.55%. Found: C, 70.91; H, 4.88; N, 12.98; S, 7.72%. IR: ν = 3440,
3340 cm−1 (NH2) and 1220 cm−1 (CN). 1HNMR(DMSO-d6): δ = 2.35, 2.7
(2s, 6H, 2CH3), 4.05 (s, 1H, CH-pyran), 6.6 (s, 2H, NH2), 6.2, 6.9 (2d, 4H,
CH-pyrryl), 7.05 (s, 1H, CH-pyridine), 7.2–7.7 (m, 5H, CH-aromatic).
4,6-Dimethyl-3(pyrrol-1yl)thieno[2,3-b]pyridin-2-
acetylsemicarbazone (11a)
A mixture of compound 2 (2.73 gm, 0.01 mol), semicarbazidehydrochlo-
ride (1.11 gm, 0.01 mol), and sodium acetate (1.23 gm, 0.015 mol) in
ethanol (20 mL) was heated under reflux for 5 h, allowed to cool, and
poured into cold water. The solid product was collected and recrystal-
lized from ethanol as yellow crystals, 2.23 gm, 68% yield, m.p. 298◦C.
Anal. calcd. for C16H17N5OS(327.40): C, 58.70; H, 5.23; N, 21.39; S,
9.79%. Found: C, 58.85; H, 5.05; N, 21.17; S, 10.00%. IR: ν = 3370, 3270,
1
3120 cm−1 (NH, NH2), 1675 cm−1 (C O). HNMR(DMSO-d6): δ = 2.1,
2.5, 2.9 (3s, 9H, 3CH3) , 6.2–6.4, 6.55–6.75 (2m, 4H, 4CH-pyrrolyl ring),
6.9 (s, 1H, CH-pyridine), 5.5 (s, 2H, NH2) and 9.8 (s, 1H, NH).
4,6-Dimethyl-3(pyrrol-1yl)thieno[2,3-b]pyridin-2-
acetylthiosemicarbazone (11b)
A mixture of compound 2 (2.73 gm, 0.01 mol) and thiosemicarbazide
(0.91 gm, 0.01 mol) in acetic acid (20 mL) was heated under reflux
for 2 h and then allowed to cool. The solid product was collected and
recrystallized from acetic acid as yellow crystals, 2.47 gm, 72% yield,
m.p. 270◦C.
Anal. calcd. for C16H17N5S2(343.46): C, 55.95; H, 4.99; N, 20.39; S,
18.67%. Found: C, 56.15; H, 5.21; N, 20.12; S, 18.86%. IR: ν = 3370,
1
3270, 3120 cm−1 (NH, NH2). HNMR (DMSO-d6): δ = 2.1, 2.5, 2.9 (3s,
9H, 3CH3) , 6.2–6.4, 6.55–6.75 (2m, 4H, 4CH-pyrrolyl ring), 6.9 (s, 1H,
CH-pyridine), 5.5 (s, 2H, NH2) and 9.8 (s, 1H, NH).
4,6-Dimethyl-3(pyrrol-1yl)thieno[2,3-b]pyridin-2-
acetylphenylhydrazone (11c)
A mixture of compound 2 (2.73 gm, 0.01 mol) and phenyl hydrazine (1.1
gm, 0.01 mol) in ethanol (20 mL) was heated under reflux for 5 h, allowed
to cool, and poured into cold water. The solid product was collected and
recrystallized from ethanol as yellow crystals in 74% yield, m.p. 235◦C.
Anal. calcd. for C21H20N4S(360.48): C, 69.97; H, 5.59; N, 15.54; S, 8.89%.
Found: C, 70.07; H, 5.40; N, 15.51; S, 9.08%. IR: ν = 3410 cm−1 (NH).
1HNMR(DMSO-d6): δ = 2.1, 2.5, 2.9 (3s, 9H, 3CH3) , 6.2–6.4, 6.55–6.75

2022
A. M. K. El-Dean et al.
(2m, 4H, 4CH-pyrrolyl ring), 6.9 (s, 1H, CH-pyridine), and 10.8 (s, 1H,
NH).
4,6-Dimethyl-3(pyrrol-1yl)thieno[2,3-b]pyridin-2-
acetyhydrazone (11d)
A mixture of compound 2 (2.73 gm, 0.01 mol) and hydrazine hydrate
(0.5 gm, 99%, 0.01 mol) in ethanol (20 mL) was heated under reflux
for 5 h, allowed to cool, and poured into cold water. The solid product
was collected and recrystallized from ethanol as yellow crystals, 2.1 gm,
74% yield, m.p. 208◦C.
Anal. calcd. for C15H16N4S(284.38): C, 63.35; H, 5.67; N, 19.70; S,
11.27%. Found: C, 63.52; H, 5.80; N, 19.52; S, 11.05%. IR: ν = 3370,
1
3270, 3120 cm−1 (NH, NH2). HNMR (DMSO-d6): δ = 2.1, 2.5, 2.9 (3s,
9H, 3CH3), 6.2–6.4, 6.55–6.75 (2m, 4H, 4CH-pyrrolyl ring), 6.9 (s, 1H,
CH-pyridine), 4.6 (s, 2H NH2).
The Cyclization of Thiosemicarbazone 11b
with α-Halocompounds
General Procedure
A mixture of compound 11b (3.4 gm, 0.01 mol), α-halocompound (0.01
mol), and sod. acetate (0.012 mol) in ethanol (30 mL) was refluxed for 5
h and allowed to cool. The solid product was collected, washed well with
water, and recrystallized from dioxan. Physical constants and spectral
data of compounds 12a,b and 13a,b are listed in Tables I and II.
REFERENCES
[1] I. Adachi, T. Yamamori, Y. Hiramatsu, K. Sakai, S. Mihara, M. Kawakami, M. Masui,
O. Uno, and M. Ueda, Chem. Pharm. Bull., 36, 4389 (1988).
[2] M. Ueda, T. Gemba, M. Eigyo, and Y. Adachi, European Patent Appl; EP: 519,602
(1992); C.A., 118, 94335t (1993).
[3] Y. Saito, M. Yasushi, M. Sakashita, K. Toyoda, and T. Shibazalti, European Patent
Appl; EP 535,548 (1993); C.A., 119, 117112e (1993).
[4] M. Z. A. Badr, S. A. Mahgoub, F. F. Abdel-Latif, and A. A. Abd El-Hafez, Phosphorus,
Sulfur, and Silicon, 55, 175 (1991).
[5] H. S. El-Kashef, A. A. Geies, A. M. Kamal El-Dean, and A. A. Abdel-Hafez, J. Chem.
Tech., Biotechnol., 57, 15 (1993).
[6] E. A. Bakhite, A. A. Geies, A. M. Kamal El-Dean, and H. S. El-Kashef, Phosphorus,
Sulfur, and Silicon, 104, 143 (1995).
[7] H. S. El-Kashef, A. M. Kamal El-Dean, A. A. Geies, J. C. Lancelot, P. Dallemagne,
and S. Rault, J. Heterocyclic Chem., 37, 1521 (2000).
[8] Kh. M. Hassan, A. M. Kamal El-Dean, M. S. K. Youssef, F. M. Atta, and M. S. Abbady,
Phosphorus, Sulfur, and Silicon, 47, 181 (1990).
[9] Y. W. Ho and I. J. Wang, J. Heterocycl. Chem., 32, 819 (1995).