Reactions of hydrazonoyl halides 391: Synthesis of some new triazoles and 2,3-dihydro-1,3,4-thiadiazoles

Article abstract of DOI:10.1080/10426500490475067

C-acyl-N-phenyllhydrazonoyl halides 1a-g have been caused to react with 3-(aminomethylthiomethyl)-2H-chromen-2-one in the presence of triethylamine to give triazoles. Also, C-acyl-N-pyrazolylhydrazonoyl chlorides 13a,b react with alkyl carbodithioates (14 or 15)a-m afforded 2,3-dihydro-1,3,4-thiadiazoles in good yields. Structures of the new compounds were elucidated on the basis of elemental analyses, spectral data, and alternative methods of synthesis whenever possible.

Full text of DOI:10.1080/10426500490475067

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REACTIONS OF HYDRAZONOYL
1
HALIDES 39 : SYNTHESIS OF
SOME NEW TRIAZOLES AND 2,3-
DIHYDRO-1,3,4-THIADIAZOLES
a
a
Abdou O. Abdelhamid & Ali A. Al-Atoom
a
Department of Chemistry, Faculty of Science, Cairo
University, Giza, Egypt
Published online: 16 Aug 2010.
To cite this article: Abdou O. Abdelhamid & Ali A. Al-Atoom (2004) REACTIONS
1
OF HYDRAZONOYL HALIDES 39 : SYNTHESIS OF SOME NEW TRIAZOLES AND 2,3-
DIHYDRO-1,3,4-THIADIAZOLES, Phosphorus, Sulfur, and Silicon and the Related
Elements, 179:11, 2221-2233, DOI: 10.1080/10426500490475067
To link to this article: http://dx.doi.org/10.1080/10426500490475067
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Phosphorus, Sulfur, and Silicon, 179:2221–2233, 2004
Copyright ꢀC Taylor & Francis Inc.
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500490475067
1
REACTIONS OF HYDRAZONOYL HALIDES 39 :
SYNTHESIS OF SOME NEW TRIAZOLES AND
2,3-DIHYDRO-1,3,4-THIADIAZOLES
Abdou O. Abdelhamid and Ali A. Al-Atoom
Department of Chemistry, Faculty of Science, Cairo University,
Giza, Egypt
(
Received November 6, 2003; accepted March 27, 2004)
C-acyl-N-phenyllhydrazonoyl halides 1a–g have been caused to react
with 3-(aminomethylthiomethyl)-2H-chromen-2-one in the presence of
triethylamine to give triazoles. Also, C-acyl-N-pyrazolylhydrazonoyl
chlorides 13a,b react with alkyl carbodithioates (14 or 15)a–m af-
forded 2,3-dihydro-1,3,4-thiadiazoles in good yields. Structures of the
new compounds were elucidated on the basis of elemental analyses,
spectral data, and alternative methods of synthesis whenever possible.
Keywords:
1,2,4-triazoles;
1,3-dipolar
cycloaddition;
1,3,4-
thiadiazoles; 2H-chromen-2-one; carbodithioates; hydrazonoyl
halides; thiocarbamates
INTRODUCTION
Pyrazoles and annelated pyrazoles have long been known to exhibit di-
verse biological activities.2 Among these activities include their use as
CAMP phosphodiesterase inhibitors, antipyretic,antitumor, hypnotic
and herbicidal agents. Moreover, 1,3,4-thiadiazole and its derivatives
have become very useful compound in medicine, agriculture and in
–7
8
many fields of technology. It was of value to combine the two moi-
eties in a series of derivatives with the objective of investigating their
expected biological activities.
RESULTS AND DISCUSSIONS
Treatment of hydrazonoyl chloride 1a with 3-(aminothioxomethyl)-2H-
chromen-2-one (2) in ethanolic triethylamine afforded three products
Address correspondence to Abdou O. Abdelhamid, Department of Chemistry, Faculty
of Science, Cairo University, Giza 12316, Egypt. E-mail: Abdou@main-scc.cairo.eun.eg
2
221

2
222
A. O. Abdelhamid and A. A. Al-Atoom
according to TLC. The structures of these products elucidated on the
basis of elemental analyses, spectral data, and alternative synthe-
sis method. Thus, IR spectrum of the first product revealed bands
1
at 3330 (NH) and 1701 (CO), and its H NMR (δ ppm) spectrum
showed signals at δ = 1.22 (t, 6H), 4.20 (q, 4H), 7.01–7.47 (m, 10H),
and 10.83 (s, br., 2H). Based on these data the product formulated
as ethyl 2-[2-aza-1-(ethoxycarbonyl)-2-(phenylamino)vinylthio]-3-aza-
3-(phenylamino)prop-2-enoate (5). Structure 5 was further confirmed
by independent synthesis. Thus, cyanothioacetamide treated with 1a
9
to produce a product proved to be identical in all respects (m.p., mixed
m.p., and spectra) with 5. IR spectrum of the second product revealed
1
bands at 2190 (CN) and 1720 (CO) and its H NMR (δ ppm) spectrum
showed signals at δ = 7.23–7.78 (m, 4H, ArHs) and 9.30 (1H, coumarin
4
-H). Also, this compound showed no depression in m.p. with authen-
1
0
tic sample. Based on these data, the product formulated as 2-oxo-
-H-chromene-3-carbonitrile (6). IR spectrum of the third product re-
2
1
vealed bands at 1740, 1715 (COs), and its H NMR (δ ppm) spectrum
showed signals at δ = 1.32 (t, 3H, CH2CH3), 4.29 (q, 2H, CH2CH3), 7.21–
7
.63 (m, 9H, ArHs) and 8.16 (1H, coumarin 4-H). Based on these data,
the product formulated as ethyl 5-(2-oxo(2H-chromen-3-yl))-1-phenyl-
,2,4-triazole-3-carboxylate (9). Structure 9 was further confirmed by
1
independent synthesis. Thus, treated S-methyl 2-oxo-2H-chromene-3-
carboximidothioate (10)11 with 1a produced a product proved to be iden-
tical in all respects (m.p., mixed m.p., and spectra) with 9a.
The formation of these products can be explained via stepwise path
involving substitution via 1,3–addition of thiol 2 to nitrile imide (gen-
erated in situ by treatment of 1a with triethylamine) or 1,3-dipolar
cycloaddition of nitrile imide to C S double bond of 2 to give inter-
mediates 4, 7, and 8 which transformed to final products 5, 6, and 9,
respectively. All attempts to isolate any intermediates were unsuccess-
ful. Structure 3 was ruled out on the basis of previous data (Scheme 1).
Analogy, the hydrazonoyl halides 1b–g reacts with S-methyl
2-oxo-2H-chromene-3-carboximidothioate (10) afforded 5-(2-oxo(2H-
chromen-3-yl))-1-phenyl-1,2,4-triazole derivatives 9b–g, respectively
(
Scheme 1).
Hydrazonoyl chloride 13a reacted with each alkyl carbodithioa-
tes1
2–14
14a or 15a gave the same product 18a via elimination of alkyl
mercaptan. Structure 18a was elucidated on the basis of elemental
analysis and spectral data. Thus, IR spectrum of 18a revealed bands
1
at 3050, 2939 (CH), 1710 (CO), 1620 (C N), and 1600 (C C). Its H
NMR spectrum showed signals at δ = 1.32 (t, 3H, CH3CH2), 4.21 (q,
2H, CH2CH3), 6.51 (s, pyrazole C-4), 7.16–7.95 (m, 11H, ArH and
NH), and 8.34 (s, 1H, CH). Structure 18a was further confirmed

New Triazoles and 2,3-Dihydro-1,3,4-Thiadiazoles
2223
SCHEME 1

2
224
A. O. Abdelhamid and A. A. Al-Atoom
by independent synthesis. Thus, 1-[5-hydrazono-4-(5-phenyl-2-H-
pyrazol-3-yl)-4,5-dihydro-[1,3,4]thiadazol-2-yl]ethanone (20), which
prepared from hydrazonoyl chloride 13a and the appropriate alkyl
hydrazinecarbodithioates,15 treated with benzaldehyde to produce
a product proved to be identical in all respects (m.p., mixed m.p.,
and spectra) with 18a (Scheme 2). Similar hydrazonoyl chloride
1
1
3a reacted with the appropriate alkyl carbodithioates 14b–m or
5b–m in ethanolic triethylamine afforded 2,3-dihydro-1,3,4-
thiadiazoles 18b–m, respectively, in a good yield.
SCHEME 2
Products 18a–m are assumed to be formed via elimination of alka-
nethiol from the corresponding cycloadduct 17, which formed from 1,3-
dipolar cycloaddition (or 1,3-addition) of nitrile imide (generated in situ
from 13a and triethylamine) to C S 14a or 15a (Scheme 2). By simi-
lar route, the appropriate 14a–m or 15a–m reacts with hydrazonoyl

New Triazoles and 2,3-Dihydro-1,3,4-Thiadiazoles
2225
chloride 13b in ethanolic triethylamine gave 2,3-dihydro-1,3,4-
thiadiazoles 19a–m, respectively (Scheme 2).
Treatment of hydrazonoyl chloride 13b with methyl dithiocarba-
1
6
mate 21 in ethanolic triethylamine at room temperature afforded one
isolable product 24 (Scheme 3). Structure 24 was confirmed by elemen-
1
tal analysis and spectral data. H NMR spectrum of 24b showed signals
at δ = 2.34 (s, 3H, CH3), and 6.99–8.57 (m, 11H, ArH and pyrazole C-4).
Formation of 24 can be explained via stepwise path involving substi-
tution via 1,3-addition of thiol 21 to nitrile imide (generate in situ by
SCHEME 3

2
226
A. O. Abdelhamid and A. A. Al-Atoom
treatment of 13 with triethylamine) or 1,3-dipolar cycloaddition of ni-
trile imide to C S double bond of 21 to give intermediates 22 and 23,
which transformed to final products 24 via elimination of methyl mer-
captan (Scheme 3).
Analogy, hydrazonoyl chloride 13a reacted with each 3-{aza-
1
7
[
2
(
(methylthiothioxomethyl)amino]methylene}indolin-2-one
(25) or
1
7
-{aza[(methylthiothioxomethyl)amino]methylene}indane-1,3-dione
27) or 3-methyl-4-(methylthiothioxomethyl)-1-phenyl-2-pyrazolin-5-
1
8
19
one (29) or 2-benzothiazol-2-yl-3-methylthio-3-thioxopropanenitrile
(
31) in ethanolic triethylamine to afford ethyl 2-[1,2-diaza-2-(2-
oxoindolin-3-ylidene)ethylidene]-3-(3-phenylpyrazol-5-yl-1,3,4-thiad
iazoline-5-carboxylate (26a), ethyl 2-[1,2-diaza-2-(1,3-dioxoindan-2-
ylidene)ethylidene]-3-(3-phenylpyrazol-5-yl)-1,3,4-thiadiazoline-5-car-
boxylate (28a), ethyl 2-(3-methyl-5-oxo-1-phenyl(2-pyrazolin-4-yli-
dene))-3-(3-phenylpyrazo;-5-yl)-1,3,4-thiadiazoline-5-carboxylate(30a),
and
ethyl
2-(benzothiazol-2-ylcyanomethylene)-3-phenyl-1,3,4-
thiadiazolin-5-carboxylate (32a), respectively (Scheme 3). By a
similar route, hydrazonoyl chlorides 13b reacted with the appropriate
2
5, 27, 29, or 31 afforded 2,3-dihydro-1,3,4-thiadiazoles 26b, 28b, 30b
and 32b, respectively.
Finally, the appropriate hydrazonoyl chlorides 13a,b reacted with
ethyl 6-methyl-2-methylthio-4-phenyl-3,4,5,6,-teterahydropyrmidine-
2
7
5
-carboxylate (33) in ethanolic sodium ethoxide gave triazolo[4,3-
a]pyrimidine 36a and 36b, respectively (Scheme 4).
The structure of 36 was elucidated on the basis of elemental anal-
yses, spectral data, and independent method synthesis. IR spectra of
3
6 revealed bands near 1712, 1665 (CO), 1625 (C N), and 1595 (C C).
1
H NMR spectra of 36b showed signals at δ = 1.18 (t, 3H, CH2CH3),
2
.32 (s, 3H, CH3), 2.37 (s, 3H, CH3), 4.09 (q, 2H, CH2CH3), 5.14 (s, 1H,
Pyrimidine C-4), 6.12 (s, 1H, pyrazole C-4), 7.20–7.96 (m, 10H, ArHs),
and 8.10 (s, 1H, NH). The formation of 36 can be explained via 1,3-
dipolar cycloaddition or 1,3-addition of nitrile imides (prepared in situ
from hydrazonoyl halides 13 with triethylamine or sodium ethoxide) to
3
3 to give intermediates 34 and 35, which gave final products 36 by
elimination of methyl mercaptan (Scheme 4).
EXPERIMENTAL
All melting points were determined on an electrothermal apparatus and
are uncorrected. IR spectra were recorded (KBr discs) on a Shimadzu
1
FTIR 8201 PC spectrophotometer. H NMR spectra were recorded in
CDCl3 and (CD3)2SO on a Varian Gemini 200 MHz spectrometer, and

New Triazoles and 2,3-Dihydro-1,3,4-Thiadiazoles
2227
SCHEME 4
chemical shifts were expressed in δ units using TMS as internal ref-
erence. Elemental analyses were carried out at the Microanalytical
Center of the University of Cairo, Giza, Egypt. Hydrazonoyl halides
2
1–26
27
12–14
1
a–g,
13a,b, and alkyl carbodithioates (14–15)a–m
were
prepared as previously reported.
Reaction of 1 with 3-(Aminothioxomethyl)-2H-chromen-
-one (2)
2
Triethylamine (0.5 g, 0.75 ml, 5 mmol) was added dropwise while stir-
ring to a mixture of the hydrazonoyl chloride 1a (1.13 g, 5 mmol) and 3-
(
(
aminothioxomethyl)-2H-chromen-2-one (2) (1.03 g, 5 mmol) in ethanol
20 ml) at room temperature for 30 min. The yellow solid formed was
collected and crystallized from ethanol to give 5. The filtrate evaporates
to its half volume under reduced pressure and cooling. The solid was
collected and crystallized from acetic acid to afford compound 6. The
final filtrate was evaporated, and the residue oil was triturated with
methanol afforded 9a (which crystallized from ethanol).

2
228
A. O. Abdelhamid and A. A. Al-Atoom
Synthesis of 1.2,4-Triazole 9a–g
Triethylamine (0.5 g, 0.75 ml, 5 mmol) was added dropwise while stir-
ring to a mixture of the appropriate hydrazonoyl halides 1a–g and
S-methyl 2-oxo-2H-chromene-3-carboximidothioate (10) (5 mmol each)
in ethanol (20 ml) for 2 h. The solid formed was collect, washed with
water and crystallized from ethanol to give 1,2,4-triazoles 9a–g, respec-
tively (Tables I–III).
Synthesis of 2,3-Dihydro-1,3,4-thiadiazoles (18,19)a–m
Method A
Triethylamine (0.5 g, 0.75 ml, 5 mmol) was added dropwise with
stirring to a mixture of the appropriate alkyl carbodithioates (14–15)a–
m (5 mmol) and appropriate hydrazonoyl chlorides 13a,b (5 mmol) in
ethanol (20 ml). The resulting solid, which formed after 30 min, was
collected and crystallized from acetic acid gave the corresponding 2,3-
dihydro-1,3,4-thiadiazoles 18a–m and 19a–m, respectively in a good
yield (Tables I–III).
Method B
A mixture of hydrazine derivative 20a (1.65 g, 5 mmol) and benzalde-
hyde (0.53 g, 5 mmol) in ethanol (20 ml) was stirred for 30 min. The solid
formed was collect, washed with water, and crystallized from ethanol
gave products identical in all respects (m.p., mixed m.p., and spectra)
with 18a.
Synthesis of 2,3-Dihydro-1,3,4-thiadiazoles 24, 26, 28,
3
0, and 32
Triethylamine (0.5 g, 0.75 ml, 5 mmol) was added dropwise
while stirring to a mixture of the appropriate hydrazonoyl chlo-
rides 13a,b and the appropriate S-methyl phenylthiocarbamate—
3
2
-{aza[(methylthiothioxomethyl)amino]methylene}indolin-2-one (25),
{aza[(methylthiothioxomethyl)amino]methylene}indane-1,3-dione
(
(
(
27), 3-methyl-4-(methylthiothioxomethyl)-1-phenyl-2-pyrazolin-5-one
29), 2-benzothiazol-2-yl-3-methylthio-3-thioxopropanenitrile (31)
5 mmol each)—in ethanol (20 ml) for 2 h. The solid formed was
collected, washed with water and crystallized from ethanol to give
,3-dihydro- 1,2,4-thiadiazoles 24, 26, 28, 30, and 32, respectively
Tables I and II).
2
(

New Triazoles and 2,3-Dihydro-1,3,4-Thiadiazoles
2229
TABLE I Characterization Data of the Newly Synthesized Compounds
Calcd./found (%)
◦
Comp. m.p. ( C)
no.
Color
yield (%)
Mol. formula
mol. wt.
solvent
C
H
N
S
9
9
9
9
9
9
9
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
a
211–212
EtOH
224–225
EtOH
189–190
EtOH
218–219
EtOH
205–207
EtOH
175–176
EtOH
168–169
EtOH
170–172
EtOH
142–144
EtOH
151–152
EtOH
202–203
EtOH
201–203
EtOH
237–238
AcOH
222–223
EtOH
224–226
AcOH
248–250
AcOH
243–244
AcOH
212–214
EtOH
239–240
AcOH
218–220
AcOH
223–225
AcOH
165–167
AcOH
160–161
EtOH
Pale brown
50
Pale brown
55
Brown
52
Pale brown
60
Pale orange
55
Green
25
Deep brown
40
Yellow
73
Yellow
70
Yellow
80
Yellow
60
Yellow
66
Yellow
75
Gold
68
Yellow
85
Yellow
60
Yellow
65
Yellow
68
Yellow
80
Yellow
78
Yellow
75
Yellow
65
Orange
72
C20H15N3O4
361.36
C19H13N3O4
347.33
C19H13N3O3
331.34
C24H16N4O3
408.42
C24H15N3O3
393.41
C22H13N3O3S
399.43
C28H17N3O3
443.47
C21H18N6O2S
418.48
C22H20N6O2S
432.51
C19H16N6O3S
408.44
C19H16N6O3S2
424.51
C20H18N7O2S
420.48
C22H20N6O2S
432.51
C20H18N6O3S
422.47
C20H18N6O2S2
438.53
C21H19N7O2S
433.50
C19H20N6O2S
396.48
C20H22N6O2S
410.50
C21H24N6O2S
424.53
C24H22N6O2S
458.55
C20H16N6OS
388.45
C21H18N6OS
402.47
C18H14N6O2S
378.42
66.48
66.62
65.70
65.92
68.87
68.78
70.58
70.70
73.27
73.30
66.15
66.25
75.84
75.98
60.27
60.70
61.10
60.90
55.87
55.65
53.76
53.60
57.13
57.14
61.10
61.24
56.86
56.98
54.78
54.80
58.19
58.26
57.56
57.42
58.52
58.63
59.41
59.50
62.86
62.72
61.84
61.90
62.67
62.75
57.13
57.25
4.18
4.00
3.44
3.45
3.95
4.10
3.95
3.75
3.84
3.90
3.28
3.40
3.86
3.60
4.34
4.34
4.66
4.65
3.95
4.10
3.80
4.10
4.32
4.39
4.66
4.87
4.29
4.13
4.14
4.06
4.42
4.61
5.08
5.26
5.40
5.55
5.70
5.40
4.84
4.80
4.15
4.30
4.51
4.60
3.73
3.90
11.36
11.50
12.10
12.30
12.68
12.80
13.72
13.56
10.68
10.70
9.48
—
b
—
—
c
d
—
e
—
f
10.82
—
9.70
9.48
9.62
g
8a
8b
8c
8d
8e
8f
8g
8h
8i
8j
8k
8l
8m
9a
9b
9c
20.08
20.20
19.34
19.43
20.58
20.70
19.80
19.90
23.32
23.20
19.43
19.34
19.89
19.90
19.16
19.30
22.62
22.42
21.20
21.10
20.47
20.30
19.80
19.65
18.33
18.52
21.63
21.80
20.88
20.75
22.21
22.40
7.66
7.50
7.41
7.32
7.85
7.90
15.11
14.95
7.63
7.30
7.41
7.30
7.59
7.65
14.62
14.40
7.40
7.52
8.09
7.90
7.81
7.70
7.55
7.52
6.99
6.78
8.25
8.50
7.97
8.20
8.47
8.60
(
Continued on next page)

2
230
A. O. Abdelhamid and A. A. Al-Atoom
TABLE I Characterization Data of the Newly Synthesized Compounds
Continued)
(
Calcd./found (%)
◦
Comp. m.p. ( C)
no.
Color
yield (%)
Mol. formula
mol. wt.
solvent
C
H
N
S
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
3
3
3
3
3
3
9d
188–189
EtOH
179–181
EtOH
235–236
AcOH
233–234
AcOH
190–192
AcOH
>300
AcOH
148–149
EtOH
148–150
EtOH
133–134
EtOH
233–234
AcOH
85–87
EtOH
234–245
EtOH
172–173
EtOH
289–291
DMF
>315
DMF
200–202
AcOH
213–215
AcOH
152–154
AcOH
289–291
AcOH
274–246
DMF
279–281
DMF
Brown
65
Pale brown
60
Yellow
74
Yellow
62
Brown
65
Yellow
71
Yellow
68
Yellow
58
Yellow
67
Yellow
75
Yellow
65
Yellow
55
Yellow
65
Orange
78
Orange
80
Red
60
Red
70
Yellow
75
Yellow
70
Yellow
68
Yellow
55
Yellow
65
C18H14N6OS2
394.48
C19H15N7OS
389.44
C21H18N6OS
402.47
C19H16N6O2S
392.44
C19H16N6OS2
408.51
C20H17N7OS
403.47
C18H18N6OS
366.45
C19H20N6OS
380.48
C20H22N6OS
394.50
C23H20N6OS
428.52
C14H14N6O2S
330.37
C20H17N5O2S
391.46
C19H15N5OS
361.43
C22H17N7O3S
459.49
C21H15N7O2S
429.46
C23H16N6O4S
444.47
C22H14N4O3S
472.49
C24H20N6O3S
472.53
C23H18N6O2S
442.50
C23H16N6O2S2
472.55
C22H14N6OS2
442.52
C27H26N6O4
498.55
C26H26N6O4
468.52
54.81
54.60
58.60
58.50
62.67
62.70
58.15
58.30
55.86
55.60
59.54
59.60
59.00
59.20
59.98
59.30
60.89
61.10
64.47
64.50
50.90
50.66
61.37
61.56
63.14
63.12
57.51
57.72
58.73
58.90
62.15
62.24
58.47
58.20
61.00
60.80
62.43
62.50
58.46
58.60
59.71
59.90
65.05
55.90
66.65
66.50
3.58
3.70
3.88
4.00
4.51
4.60
4.11
4.20
3.95
3.80
4.25
4.30
4.95
4.80
5.30
5.10
5.62
5.70
4.70
4.60
4.27
4.40
4.38
4.25
4.18
3.10
3.73
3.94
3.52
3.30
3.63
3.50
3.41
3.50
4.27
4.30
4.10
4.20
3.14
3.30
3.19
2.90
5.26
5.10
5.16
5.00
21.30
21.10
25.18
25.40
20.88
21.10
21.42
21.20
20.57
20.70
24.30
24.50
22.93
23.10
22.10
22.00
21.30
21.10
19.61
19.40
25.44
25.15
17.89
17.90
19.38
19.40
21.34
21.45
22.83
22.70
12.61
12.52
17.79
17.90
17.79
17.50
18.99
18.90
17.78
17.60
18.99
18.65
16.89
16.70
17.94
18.10
16.26
16.30
8.23
8.28
7.97
8.20
8.17
8.00
15.70
15.60
7.95
8.00
8.75
8.90
8.34
8.40
8.13
8.10
7.48
7.60
9.71
9.80
8.19
8.24
8.87
8.70
6.98
7.24
7.47
7.60
7.21
7.10
6.79
7.10
6.79
6.62
7.25
7.00
13.57
13.60
14.49
14.52
—
9e
9f
9g
9h
9i
9j
9k
9l
9m
0
4a
4b
6a
6b
8a
8b
0a
0b
2a
2b
6a
6b
206–207
EtOH
148–150
EtOH
Yellowish-
brown
—

New Triazoles and 2,3-Dihydro-1,3,4-Thiadiazoles
2231
TABLE II 1H NMR Spectra of Some Selected Synthesized Compounds
Compd. no.
1H NMR (δ ppm)
9
9
9
9
9
9
b
c
d
e
f
3.88 (s, 3H), 7.20–7.63 (m, 9H) and 8.16 (s, 1H)
2.55 (s, 3H), 7.20–7.63 (m, 9H) and 8.16 (s, 1H)
7.20–7.63 (m, 14 H), 8.16 (s, 1H) and 9.25 (s, br., 1H)
7.20–7.65 (m, 14 H) and 8.16 (s, 1H)
7.06–7.65 (m, 12 H) and 8.16 (s, 1H)
7.20–7.63 (m, 15 H), 8.16 (s, 1H) and 8.22 (s, 1H)
g
1
8b
1.30 (t, 3H), 2.35 (s, 3H), 4.20 (q, 2H), 6.50 (s, 1H), 7.10–7.50 (m, 9H),
.10 (s, 1H), and 8.45 (s, 1H)
1.30 (t, 3H), 4.20 (q, 2H), 6.30 (d, 1H), 6.35 (t, 1H), 6.5 (s, 1H), 7.22–7.48
m, 7H), and 8.32 (s, 1H)
8
1
8c
(
1
1
1
8d
8e
8f
1.30 (t, 3H), 4.20 (q, 2H), 6.50 (s, 1H), 7.22–7.48 (m, 9H), and 8.32 (s, 1H)
1.3 (t, 3H), 4.20 (q, 2H), 6.50 (s, 1H), and 7.21–9.32 (m, 11H)
1.30 (t, 3H), 2.00 (s, 3H), 4.22 (q, 2H), 6.5 (s, 1H), 7.22–7.60 (m, 10 H),
and 8.62 (s, 1H)
1
1
1
1
1
1
1
8g
8h
8i
1.30 (t, 3H), 2.00 (s, 3H), 4.20 (q, 2H), 6.3 (m, 2H), 6.5 (s, 1H), 7.22–7.48
(
m, 6 H), and 8.90 (s, 1H)
1.30 (t, 3H), 2.10 (s, 3H), 4.22 (q, 2H), 6.50 (s, 1H), 7.00–7.48 (m, 8 H),
and 8.80 (s, 1H)
1.30 (t, 3H), 2.09 (s, 3H), 4.22 (q, 2H), 6.50 (s, 1H), and 7.00–9.12
(
m, 10 H)
1.22 (t, 3H), 1.35 (t, 4H), 1.37 (m, 4H), 4.41 (q, 2H), 6.50 (s, 1H),
.22–7.48 (m, 5 H) and 8.82 (s, 1H)
2.20(s, 3H), 6.50 (s, 1H), 7.20–7.63 (m, 10H), 8.16 (s, 1H), and 8.45
s, br., 1H)
2.20 (s, 3H), 2.35 (s, 3H), 6.50 (s, 1H), 7.10–7.50 (m, 9H), 8.10 (s, 1H), and
.45 (s, 1H)
2.20 (s, 3H), 6.30 (d, 1H), 6.35 (t, 1H), 6.5 (s, 1H), 7.22–7.48 (m, 7H), and
.32 (s, 1H)
8j
7
9a
9b
9c
(
8
8
1
1
1
1
1
1
3
9d
9e
9f
9g
9h
9i
2.20 (s, 3H), 6.50 (s, 1H), 7.22–7.48 (m, 9H), and 8.32 (s, 1H)
2.21 (s, 3H), 6.53 (s, 1H), and 7.21–9.32 (m, 11H)
2.00 (s, 3H), 2.20 (s, 3H), 6.5 (s, 1H), 7.22–7.60 (m, 10 H), and 8.62 (s, 1H)
2.10 (s, 3H), 2.30 (s, 3H), 6.50 (s, 1H), 7.00–7.48 (m, 8 H), and 8.80 (s, 1H)
2.10 (s, 3H), 2.23 (s, 3H), 6.50 (s, 1H), 7.00–7.48 (m, 8 H), and 8.80 (s, 1H)
2.09 (s, 3H), 2.20 (s, 3H), 6.50 (s, 1H), and 7.00–9.12 (m, 10 H)
1.30 (t, 6H), 1.71 (s, 3H), 4.19 (q, 2H), 4.20 (q, 2H), 4.59 (s, 1H), 6.50
6a
(
s, 1H), 7.06–7.48 (m, 10 H), and 9.50 (s, 1H)
TABLE III 13C NMR Spectra of Some Selected Synthesized Compounds
Compd. no.
13C NMR (δ ppm)
9
a
13.6, 59.1, 121, 125, 126, 127, 128, 129, 140, 150, 154, 162, 167
13.3, 58.9, 90, 127, 128, 129, 130, 131, 136, 149, 154, 155, 161, 163, 164
13.3, 58, 91, 110, 127, 128, 129, 136, 143, 149, 154, 155, 161, 163, 164
13.3, 13.7, 17, 59.3, 59.9, 91, 123, 126, 127, 128, 129, 136, 142, 161,
1
1
3
8a
8c
6a
163, 165

2
232
A. O. Abdelhamid and A. A. Al-Atoom
Synthesis of Ethyl 5-Hydrazono-4-(5-phenyl-2H-pyrazol-
-yl)-4,5-dihydro-[1,3,4-]thiadiazole-2-carboxylate (20)
3
Triethylamine (0.5 g, 0.75 ml, 5 mmol) was added dropwise to amix-
ture of equimolar quantities of C-ethoxycarbonyl-N-(5-phenyl)pyrazol-
3-ylhydrazonoyl chloride (13a) and methyl hydrazinecarbodithioate
(
5 mmol each) in ethanol (15 ml) while stirring for 2 h. The resulting
solid was collected and crystallized from ethanol to give 20 (Tables I
and II).
Synthesis of Triazolo[4,3-a]Pyrimidines 36a,b
Method A
An equimolar amount of each of the appropriate hydrazonoyl chlo-
rides 13a,b and sodium ethoxide (5 mmol) in ethanol (20 ml) was re-
fluxed for 3 h. The reaction mixture was cooled, and the resulting solid
was collected and crystallized from ethanol to give 36a and 36b, respec-
tively (Tables I–II).
Method B
A mixture of the appropriate hydrazonoyl chlorides 13a,b (5 mmol)
and compound 37 (1.37 g, 5 mmol) in chloroform (20 ml) containing
triethylamine (0.5 g, 0.75 ml, 5 mmol) was refluxed for 10 h. Chloro-
form was evaporated under reduced pressure, and the residue solid
was crystallized from ethanol to give products identical in all respects
(
m.p., mixed m.p., and spectra) with corresponding products obtained
by method A.
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