Reactions with hydrazonoyl halides 601: Synthesis of thieno[2',3':4,5] pyrimidino[1,2-b][1,2,4,5]tetrazines, [1]benzothieno[2',3':4, 5]pyrimidino [1,2-b][1,2,4,5]tetrazines, pyrazolo[3',4':4,5]pyrimidino[1,2-b] [1,2,4,5]tetrazines and pyrazolo[3,4-d]pyridazines

Article abstract of DOI:10.3184/030823407X256118

Thieno[2',3':4,5]pyrimidino[1,2-b][1,2,4/5]tetrazine,[1]benzothieno-[2',3': 4,5]pyrimidino[1,2-b)][1,2,4,5]tetrazine, pyrazolo [2',3':4,5]pyrimidinon[1,2-b] [1,2,4,5]tetrazine, triazolo[4,3-a]pyrimidin-5(1H)-one, 1-{[2-(1-benzofuran-2- yl)-5-phenyl-4,5-dihydro-1H-pyrazol-1-yl]-4-substituted-1,3-thiazol-5-yl} -2-phenyldiazene, 3-acyl-4-(1-benzofuran-2-ylcarbonyl) pyrazole and pyrazolo[3,4-d]pyridazine derivatives could be obtained via reactions of hydrazonoyl halides with the appropriate pyrimidine-2-thione, 3-amino-5,6-dimethyl-2-sulfanylthieno[2,3-d]pyrimidin-4(3H)-one, 5-amino-6-mercapto-1-phenyl-1,5-dihydropyrazolo[3,4-d]pyrimidin-4-one and 1-(benzofuran-2-yl)-3-(dimethylamino)prop-2-en-1-one. Structures of the products have been determined by elemental analyses, spectral data studies and alternative synthesis whenever possible.

Full text of DOI:10.3184/030823407X256118

JOURNaL OF ChEMICaL RESEaRCh 2007
OCTObER, 609–616
RESEARCH PAPER 609
Reactions with hydrazonoyl halides 601: synthesis of thieno[2',3':4,5]
pyrimidino[1,2-b][1,2,4,5]tetrazines, [1]benzothieno[2',3':4,5]pyrimidino
[1,2-b][1,2,4,5]tetrazines, pyrazolo[3',4':4,5]pyrimidino[1,2-b]
[1,2,4,5]tetrazines and pyrazolo[3,4-dꢀ]pyridazines
Abdou O. Abdelhamida*, Zeineb H. Ismailb and Anhar Abdel-Aziemb
aDepartment of chemistry, Faculty of Science, cairo University, Giza 12613, Egypt
bDepartment of chemistry, Faculty of Science (Girls Branch), Al-Azhar University, cairo, Egypt
Thieno[2’,3’:4,5]pyrimidino[1,2-b][1,2,4,5]tetrazine,[1]benzothieno-[2’,3’:4,5]pyrimidino[1,2-b][1,2,4,5]tetrazine,pyrazolo
[3’,4’:4,5]pyrimidino[1,2-b][1,2,4,5]tetrazine, triazolo[4,3-a]pyrimidin-5(1H)-one, 1-{[2-(1-benzofuran-2-yl)-5-phenyl-
4,5-dihydro-1H-pyrazol-1-yl]-4-substituted-1,3-thiazol-5-yl}-2-phenyldiazene,
3-acyl-4-(1-benzofuran-2-ylcarbonyl)
pyrazole and pyrazolo[3,4-d]pyridazine derivatives could be obtained via reactions of hydrazonoyl halides with
the appropriate pyrimidine-2-thione, 3-amino-5,6-dimethyl-2-sulfanylthieno[2,3-d]pyrimidin-4(3H)-one, 5-amino-6-
mercapto-1-phenyl-1,5-dihydropyrazolo[3,4-d]pyrimidin-4-one and 1-(benzofuran-2-yl)-3-(dimethylamino)prop-2-en-
1-one. Structures of the products have been determined by elemental analyses, spectral data studies and alternative
synthesis whenever possible.
Keywords: tetrazino[2,3-a]thieno[2,3-d]pyrimidine, triazolo[4,3-a]pyrimidine, pyrazolo[3,4-d]pyrimidines, pyrimidine-2-thione,
hydrazonoyl halides
hydrazonoyl halides have been widely used for the synthesis
of heterocyclic compounds.2-7 a large number of thiazole
derivatives have been found to exhibit pharmacological
activity.8,9 They are used also as an anthelmintic,10 fungicidal,11
antifungalactivity, inhibitinginvivothegrowthofXanthomonas
oryzae,12 and ingredient of herbicides.13 Pyrimidotetrazines
have been reported to exhibit a range of biological activities.14,15
also, triazolopyrimidines have been reported to exhibit in
vivo leishmanicidal activity against the amastigate stage of
leishmania donovani16,17 and cardiovascular activity.18,19
They are cardiotonics; coronary vasodilators and they have
antihypertensive properties.20 They act against aspergillus and
Pencicillium species21 and have been tested as microbicidal
and bioregulator agents.22 we report here the synthesis of
some new thieno[2',3':4,5]pyrimidino[1,2-b][1,2,4,5]tetrazine,
[1]benzothieno-[2',3':4,5]pyrimidino[1,2-b][1,2,4,5]tetrazine,
pyrazolo[3',4':4,5]-pyrimidino[1,2-b][1,2,4,5]tetrazine,
triazolo[4,3-a]pyrimidin-5(1H)-one,1-{[2-(1-benzofuran-2-yl)-
5-phenyl-4,5-dihydro-1H-pyrazol-1-yl]-4-substituted-1,3-
thiazol-5-yl}-2-phenyldiazene, and pyrazolo[3,4-dꢀ]pyridazine.
Results and discussion
Reaction of the appropriate hydrazonoyl halides 1a–e with
3-amino-5,6-dimethyl-2-sulfanylthieno[2,3-d]pyrimidin-
4(3H)-one23 (2a) in chloroform containing triethylamine
under reflux afforded, in each case, one isolable product as
evidenced by TLC. The isolated products were formulated as
6H-thieno[2',3':4,5]pyrimidino[1,2-b][1,2,4,5]tetrazines 6a–e
(Scheme 1) by elemental analyses and spectral data.
O
O
NH2
H3C
H3C
NH2
S
H3C
N
N
COR
N
i
+
H
N
RCOC(X):NNHPh
SR'
N
H3C
S
N
3
S
1a-e
Ph
i
2a, R' = H
2b, R' = CH3
i
O
NH2
H3C
H3C
O
H
N
N
COR
NNHPh
S
COR
H3C
N
N
H
S
N
N
SR'
H3C
N
Ph
S
4
7
i = Triethylamine
O
(1-8) a, R = OC2H5
b, R = CH3
O
H
COR
NH2
H3C
H3C
N
H3C
H3C
N
N
c, R = NHC6H5
d, R = C6H5
e, R = benzofuran-2-yl
NHCSCOR
N
N
Ph
N
N
S
N
H
S
SR'
Ph
5
8
- H2S
-R'SH
H3C
O
H
N
COR
N
N
N
Ph
H3C
N
S
6
Scheme 1
* Correspondent. E-mail: abdelhamid45@gmail.com
PAPER: 07/4804

610 JOURNaL OF ChEMICaL RESEaRCh 2007
The formation of ethyl 7,8-dimethyl-6-oxo-1-phenyl-
1,4-dihydro-6H-thieno[2',3':4,5]pyrimidino[1,2-b]
[1,2,4,5]tetrazine-3-carboxylate (6a) from the hydrazonoyl
chloride 1a and thione 2a could be accounted for the pathways
depicted in Scheme 1.
[1,2,4]triazolo[4,3-a]pyrimidin-5(1H)-one derivatives 17a–e,
respectively (Scheme 3). Structure of 17 was elucidated
on the basis of elemental analysis, spectral data and
1
alternative synthesis route. Thus, h NMR spectrum of 3-(1-
benzofuran-2-ylcarbonyl)-6,7-dimethyl-1-phenylthieno[2,3-
d][1,2,4]triazolo[4,3-a]pyrimidin-5(1H)-one (17a) showed
signals at d = 1.40 (t, J = 7.5 hz, 3h), 2.35 (s, 3h), 2.47 (s,
3h), 4.58 (q, Jꢀ= 7.5 hz, 2h), 7.03 (s, 1h), 7.13–7.55 (m, 3h),
8.16 (d, J = 7.5 hz, 2h). Its IR spectrum revealed bands at
1744 (CO ester), 1620 (C=N), 1600 (C=C). also, compound
17a was obtained from the reaction of 13b with 1a in boiling
sodiumethoxidesolution.ThemechanismoutlinedinScheme3
seems to be the most plausible pathway for the formation of
17 from the reaction of 1 with the appropriate 13a or 13b.
Two possible pathways can account for the formation of
17:1)- 1,3-addition of the thiol tautomer 13a to the nitrilium
imide, generated in situ from hydrazonoyl halides and
triethylamine, to give the thiohydrazonate ester 14 which
analogously,
2-(benzofuran-2-yl-N-phenyl-2-oxoaceto-
hydrazonoyl bromide (1e) reacted with each of 3-amino-2-
sulfanyl-5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidin-
4(3H)-one24 (9a) and 5-amino-6-mercapto-1-phenyl-1,5-
dihydropyrazolo[3,4-d]pyrimidin-4-one25 (10a) in boiling
chloroformcontainingtriethylaminetoafford3-(1-benzofuran-
2-ylcarbonyl)-1-phenyl-7,8,9,10-tetrahydro-6H-[1]benzo-
thieno[2',3':4,5]pyrimidino[1,2-b][1,2,4,5]tetrazin-6-one (11)
and 3-(1-benzofuran-2-ylcarbonyl)-1,9-diphenyl-1,4-dihydro-
6H-pyrazolo[3'4':4,5]-pyrimidino[1,2-b][1,2,4,5]tetrazin-6-
one (12) (Scheme 2).
also, treatment of the appropriate 1a–e with the pyrimidine-
2-thione23 13a in boiling chloroform gave thieno[2,3-d]
H
O
O
COR
N N
NH2
Et3N
N
RCOC(Br):NNHPh
+
N
N
Ph
SR'
N
N
S
S
N
9
11
R = Benzfuran-2-yl
a, R' = H
b, R' = CH3
O
H
N
O
N
COR
NH2
SR'
N
N
Et3N
N
N
RCOC(Br):NNHPh
+
N
N
N
N
Ph
Ph
Ph
10
12
Scheme 2
O
O
H3C
H3C
H3C
H3C
COR
NH
NH
RCOC(X):NNHPh
+
NNHPh
SR'
S
N
1
S
N
S
13
14
a, R' = H
b, R' = CH3
O
COR
NNHPh
H3C
H3C
O
O
NH
H3C
H3C
S
N
R
N
H
S
N
N
SR'
N
S
Ph
18
15
COR
O
O
H3C
H3C
H3C
H3C
N
N
N
NH
NHCSCOR
N
N
Ph
S
SR'
N
H
S
Ph
19
16
- H2S
- R'SH
COR
O
17a, R = OC2H5
b, R = CH3
c, R = NH6H5
d, R = C6H5
H3C
H3C
N
N
N
Ph
N
S
e, R = benzofuran-2-yl
17
Scheme 3
PAPER: 07/4804

JOURNaL OF ChEMICaL RESEaRCh 2007 611
undergo nucleophilic cyclisation to yield spiro compounds 15
That ring were opened to 16 which cyclised to yield 17 by loss
hydrogen sulfide; and 2)- 1,3-cycloaddition of nitrilium imide
to C=S double bond of 13a can give directly 15 (Scheme 3).
all attempts to isolate any intermediates were unsuccessful.
Treatment of 1-benzo[d]furan-2-yl-3-phenylprop-2-en-1-
one26 (20) with thiosemicarbazide (21) in boiling acetic acid
gave 3-(1-benzofuran-2-ylcarbonyl)-5-phenyl-4,5-dihydro-
1H-pyrazol-1-carbothioamide (22). Compound 22 reacted
with the appropriate hydrazonoyl halides 1b, 1d and 1e in
chloroform (or ethanol) containing triethylamine to afford 1-{[2-
(1-benzofuran-2-yl)-5-phenyl-4,5-dihydro-1H-pyrazol-1-yl]-
4-methyl-1,3-thiazol-5-yl}-2-phenyldiazene (23a), 1-{[2-1-
(benzofuran-2-yl-5-phenyl-4,5-dihydro-1H-pyrazol-1-yl]-
4-phenyl-1,3-thiazol-5-yl)}-2-phenyldiazine (23b) and 1-{[2-1-
(benzofuran-2-yl-5-phenyl-4,5-dihydro-1H-pyrazol-1-yl]-
4-(benzofuran-2-yl)-1,3-thiazol-5-yl)}-2-phenyldiazine (23c),
respectively (Scheme 4).
Structure 23 was confirmed by elemental analysis, spectral
data and alternative synthesis. Thus, benzenediazonium
chloride reacted with 2-[3-(1-benzofuran-2-yl)-5-phenyl-4,5-
dihydro-1H-pyrazol-1-yl]-4-phenyl-1,3-thiazole (24b), which
prepared via reaction of 22 with ω-bromoacetophenone, in
pyridine to give product identical in all aspects (m.p., mixed
m.p. and spectra) with 23b.
also,
1-aza-2-[(benzofuran-2-yl)prop-1-enyl][4-phenyl-
5-(phenyldiazenyl)]-1,3-thiazol-2-amine (27b) reacted with
benzaldehyde in sodium hydroxide solution (10%) to give a
product identical in all aspects (m.p., mixed m.p. and spectra)
with 23b (Scheme 4).
Treatment of C-ethoxycarbonyl-N-phenylhydrazonoyl
chloride 1a with 1-(benzofuran-2-yl)-3-(dimethylamino)prop-
2-en-1-one27 (28) in refluxing toluene containing triethylamine
yielded ethyl 1-phenyl-4-(benzofuran-2-ylcarbonyl)pyrazole-
3-carboxylate (31a) (Scheme 5). Structure 31a was
inferred from its spectral, elemental analysis and chemical
R'
CSNH2
i
N
N
N
S
H2NNHC(S)NH2
+
Ph
RCOCH = CHPh
Ph
N
R
20
21
N
22
R
24a, R' = CH3
b, R = C6H5
iv
iii /TEA
ii
R = Benzofuran-2-yl
N
ia = CH3COCH2Cl
ib = C6H5COCH2Br
ii = benzenediazonium chloride
iii =1b, 1d, 1e
N
Ph
S
R
N
R
N
R'
N
NNHCSNH2
23a, R' = CH3
b, R' = C6H5
c, R' = benzofuran-2-yl
iv =2-acetylbenzofuran
v = NaOH (10%)
Ph
25
23
i
v
R
CH3
Ph
N
N
NH
S
ii
N
S
H3C
R
HN
N
N
N
R'
27
R'
26, 27a, R' = CH3
b, R' = C6H5
26
Scheme 4
N(CH3)2
+
Et3N
-
R =
R'COC(X):NNHPh
[R'COC:NNPh]
+
O
O
1
28
31a, R' = OC2H5
O
N(CH3)2
b, R' = HNC6H5
c, R' = CH3
d, R' = C6H6
e, R' = R
O
O
R
R
O
R'
N(CH3)2
N
N
R'
N
Ph
N
30
Ph
29
33a, R' = OH
b, R' = CH3
c, R' = C6H6
d, R' = R
O
O
O
N
N
N
R'
R
R'
O
R
R
N2H4.H2O
N
N
Ph
N
R'
N
Ph
N
Ph
33
31
32
Scheme 5
PAPER: 07/4804

612 JOURNaL OF ChEMICaL RESEaRCh 2007
transformation. Thus, 1h NMR spectrum of 31a showed
signals at δ = 1.3 (t, 3H, CH2Ch3), 4.21 (q, 2h, Ch2Ch3),
7.44–7.88 (m, 10h, arh’s) and 8.24 (s, 1h, pyrazole h-5).
Compound 31a was converted to 7-(1-benzofuran-2-
ylcarbonyl)-2-phenyl-2H-pyrazolo[3,4-d]pyridazin-4-ol
(33a) by its treatment with hydrazine hydrate in boiling
ethanol. Structure 33 was elucidated on the basis of elemental
analysis, spectral data and alternative synthesis route. 1h
NMR spectrum of 33a showed signals at δ = 7.33-7.62 (m,
10 h, arh’s), 8.23 (s, 1h, pyrazole h-5) and 11.12 (s, br., 1h,
Nh). analogously, 4-benzofuran-2-yl-1-phenyl-3-(phenyl-
carbamoyl)pyrazole (31b) reacted with hydrazine hydrate
in boiling ethanol to give an identical product in all aspects
(m.p., mixed m.p., and spectra) with 33a. Formation of 31
can be explained via reaction of nitrile imide, which formed
inꢀ situ from hydrazonoyl halides 1 and triethylamine, with
28 to afford the intermediate cyclo adduct 29 or 30 followed
by elimination of diethylamine to give the pyrazole 31 or 32
as the final isolated product. Structure 32 was ruled out on
the basis of the formation of pyrazolo[3,4-d]pyridazine 33.
Similarly, the appropriate hydrazonoyl halides 1b–e reacted
with 28 to afford corresponding pyrazoles 31b–e, respectively.
Pyrazolo[3,4-d]pyridazines 33a–d were obtained in good
yield from the reaction of the appropriate pyrazoles 31b–e
with hydrazine in boiling ethanol. Structures 33b,c were
elucidated on the basis of elemental analysis and spectral data
(experimental part).
aromatic protons). Its IR spectrum revealed bands at 1702
(CO ester), 1650 (CO conjugated) and 1615 (C=N). Thus,
hydrazonoyl bromide 1e reacted with ethyl 6-methyl-4-phenyl-
2-methylsulfanyl-1,6-dihydropyrimidine-5-carboxylate28
(39a) in boiling sodium methoxide to give product identical in
all aspects (m.p., mixed m.p., and spectra) with 38a.
Two possible pathways can account for the formation 38:
(1) 1,3-addition of the thiol, tautomer 34 to the nitrilium
imide, which generated inꢀsitu by treatment of hydrazonoyl
bromide 1e with triethylamine, can give the thiohydrazonate
ester 35 which undergo nucleophilic cyclisation to yield spiro
compounds 36. The latter intermediate 36 were ring opened to
37 which were cyclised to yield 38 by loss hydrogen sulfide;
and (2) 1,3-cycloaddition of nitrilium imide to C=S double
bond of 34 to give directly 36 (Scheme 6).
Experimental
all melting points were determined on an electrothermal apparatus
and are uncorrected. IR spectra were recorded (Kbr discs) on a
Shimadzu FT-IR 8201 PC spectrophotometer. 1h NMR and 13C NMR
spectra were recorded in CDCl3 and (CD3)2SO solutions on a Varian
Gemini 300 MHz spectrometer and chemical shifts are expressed in δ
units using TMS as an internal reference. Mass spectra was recorded
in on a GC-MS QP 1000 EX Schimadzu. Elemental analyses and
microorganism tests were carried out at the Microanalytical Centre of
the Cairo University. hydrazonoyl halides30-34 1a–e were obtained as
previously reported.
Treatment of hydrazonoyl bromide 1e with the
appropriate ethyl ethyl 4-aryl-6-methyl-2-thioxo-1,2,3,4-
tetrahydropyrimidin-5-carboxylate28,29 34a–d in boiling
chloroform under reflux gave the triazolo[4,3-a]pyrimidines
38a–d, respectively (Scheme 6). The structure of 38 was
elucidated on the basis elemental analysis, spectral data and
alternative synthesis route. Thus, h NMR spectrum of 38a
showed signals at d = 1.23 (t, 3h, J = 7.5 hz), 2.56 (s, 3h),
4.09 (q, 2h, J = 7.5 hz), 5.65 (s, 1h), 7.16–8.24 (m, 15h,
Synthesisꢀof 6a–d, 11, 12, 17a–e and 38a–d
MethodꢀA: a mixture of the appropriate 2a, 9a, 10a, 13a or 34a-d
(5 mmoles), the appropriate hydrazonoyl halides 1a–e (5 mmoles)
and triethylamine (1.5 ml, 5 mmoles) in boiling chloroform (20 ml)
under reflux for 10 hrs. Chloroform was evaporated under reduce
pressure and the resulting solid was triturated with petroleum ether
40–60°C. The resulting solid was collected and recrystallised from
the proper solvent to give 6a–e, 11, 12, 17a–e and 38a–d, respectively
(Tables 1 and 2).
1
Ar
Ar
C2H5O2C
C2H5O2C
Et3N
NH COR
NH
NHPh
RCOC(Br):NNHPh
+
H3C
N
35
S
N
H3C
N
H
S
1e
34
Ar
+
-
C2H5O2C
H3C
RCOC:NNPh
NH
S
COR
N
H
N
N
Ph
R = benzofuran-2-yl
36
a, Ar = C6H5
b, Ar =4-CH(CH3)2C6H4
Ar
c, Ar = 2,4-(CH3O)2C6H3
d, Ar = 2,3-(CH2O2)C6H3
C2H5O2C
H3C
NH
N
SH
COR
N
N
Ph
37
Ar
COR
N
Ar
C2H5O2C
H3C
C2H5O2C
H3C
N
CH3ONa
NH
N
RCOC(Br):NNHPh
+
N
N
39
SCH3
Ph
1e
38
Scheme 6
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JOURNaL OF ChEMICaL RESEaRCh 2007 613
Table 1 Characterisation data of the newly synthesised compounds
Compd no. Mp./°C
Solvent
Yielda/%
Colour
Mol. formula
Mol. wt.
% Analyses, Calcd./Found
C
H
N
S
6a
120–121
EtOH
90 (85)
Yellow
90 (85)
Yellow
90 (85)
Yellow
90 (85)
Red
90 (85)
Red
90 (85)
Red
C18H17N5O3S
383.42
C17H15N5O2S
353.40
C22H18N6O2S
430.48
C22H17N5O2S
415.47
C24H17N5O3S
455.50
C26H19N5O3S
481.54
C27H17N7O3
487.48
C18H16N4O3S
368.41
C17H14N4O2S
338.39
C22H17N5O2S
415.47
C22H16N4O2S
400.46
C24H16N4O3S
440.48
C18H15N3OS
321.40
C27H21N5OS
463.56
C32H23N5OS
525.31
C34H23N5O2S
565.64
C21H17N3OS
359.32
C26H19N3OS
421.52
C14H13N3OS
271.34
C19H15N3OS
333.41
C20H17N5OS
375.45
C25H19N5OS
437.52
C27H19N5O2S
477.55
C21H16N2O4
360.36
C25H17N3O3
407.43
C20H14N2O3
330.34
C25H16N2O3
392.41
C27H16N2O4
432.43
C19H12N4O2
328.33
C20H14N4O
326.36
C25H16N4O
388.43
C27H16N4O2
428.18
56.39
56.21
57.78
57.87
61.38
61.54
63.60
63.42
63.29
63.35
64.85
64.65
66.53
66.35
58.68
58.86
60.34
60.43
63.60
63.50
65.98
66.10
65.44
65.33
67.27
67.15
69.96
70.11
73.12
73.00
72.31
72.11
70.17
70.25
74.09
74.25
61.97
62.15
68.44
68.58
63.98
63.70
68.63
68.42
67.91
67.75
69.99
70.12
73.70
73.56
72.72
72.65
76.52
76.65
74.99
75.12
69.51
69.35
73.61
73.85
77.30
77.15
75.68
75.86
71.42
71.56
72.51
72.70
68.08
68.12
67.88
67.65
4.47
4.27
4.28
4.15
4.21
4.13
4.12
4.00
3.76
3.67
3.98
3.91
3.52
3.35
4.38
4.23
4.17
4.10
4.12
4.32
4.03
4.20
3.66
3.57
4.70
4.50
4.57
4.67
4.41
4.52
4.10
4.12
4.77
4.68
4.54
4.35
4.83
4.92
4.53
4.35
4.56
4.65
4.37
4.52
4.01
3.98
4.48
4.52
4.21
4.32
4.27
4.40
4.11
4.23
3.73
3.94
3.68
3.86
4.32
4.12
4.15
4.00
3.78
3.87
4.79
4.97
5.53
5.30
5.00
5.21
4.41
4.32
18.27
18.00
19.82
19.70
19.52
19.41
16.86
16.62
15.38
15.45
14.54
14.22
20.11
19.85
15.21
14.98
16.56
16.65
16.86
16.57
13.99
14.15
12.72
12.58
13.07
12.86
15.12
15.18
13.33
13.54
12.38
12.30
11.69
11.75
9.97
8.36
8.53
9.07
8.92
7.45
7.32
7.72
7.52
7.04
6.89
6.66
6.87
–
6b
360
EtOH
298–300
EtOH
180–182
EtOH
260–261
EtOH
200–202
EtOH
300–301
EtOH
130–131
EtOH
6c
6d
6e
11
12
85 (80)
Red
17a
17b
17c
17d
17e
22
90 (80)
Yellow
90 (80)
Yellow
90 (80)
Yellow
90 (80)
Red
85 (70)
Red
70
Colourless
80 (75)
Red
90 (75)
Red
85 (75)
Red
80
Yellow
75
Yellow
72
Pale yellow
75
Yellow
70 (65)
Red
90 (80)
Red
80 (70)
Red
80
Yellow
75
Yellow
80
Yellow
75
Brown
70
Brown
80
White
80
White
80
Orange
80
Yellow
95 (85)
Red
95 (85)
Red
95 (85)
Red
95 (85)
Red
8.70
8.62
9.47
9.52
7.72
7.65
8.01
8.18
7.28
7.32
9.98
9.89
6.92
7.12
6.10
6.35
5.68
5.86
8.92
9.12
7.61
7.85
11.82
12.00
9.61
9.85
8.53
8.34
7.33
7.21
6.71
6.56
–
180–181
EtOH
260
EtOH
270
EtOH
230–231
EtOH
240–241
AcOH
160–162
EtOH
23a
23b
23c
24a
24b
26a
26b
27a
27b
27c
31a
31b
31c
31d
31e
33a
33b
33c
33d
38a
38b
38c
38d
220
EtOH
170
EtOH
160–161
EtOH
230–232
EtOH
189–190
EtOH
270
EtOH
159–160
EtOH
149–150
EtOH
10.12
15.49
15.34
12.60
12.75
18.65
18.36
16.00
15.89
14.67
14.76
7.77
180–181
EtOH
100
EtOH
7.94
75
10.31
10.23
8.48
–
–
–
–
–
–
–
–
–
EtOH
160
EtOH
8.62
60
7.14
EtOH
7.24
70
6.48
EtOH
6.75
259–260
AcOH
210–212
EtOH
17.06
16.85
17.17
17.28
14.42
14.52
13.08
12.82
11.10
11.00
10.25
10.00
9.92
158–160
EtOH
200–202
EtOH
200
EtOH
215–216
EtOH
180–181
EtOH
C30H24N4O4
504.55
C33H30N4O4
546.63
C32H28N4O6
564.60
C31H24N4O6
548.65
10.12
10.21
10.32
220–221
EtOH
PAPER: 07/4804

614 JOURNaL OF ChEMICaL RESEaRCh 2007
Table 2 Spectral data of some newly synthesised compounds
Compd. no.
Spectral data
6a
IR: 3216 (NH), 1739, 1699 (2 CO), 1665 (C=N).
1H NMR: 1.30 (t, 3H, J = 7.5 Hz, CH2CH3), 2.21 (s, 3H, CH3), 2.41 (s, 3H, CH3), 4.2 (q, 2H, J = 7.5 Hz, CH2CH3),
6.46–7.02 (m, 5H), 9.32 (s, br., 1H, NH).
13C NMR: 9.3 (CH3), 11.1 (CH3), 13.8 (CH3), 61.1 (CH2), 116.3, 118, 118.8. 129.6, 133.5, 134, 146.3, 154, 155.8, 159.3,
161, 163.
6b
6c
6d
6e
11
IR: 3246 (NH), 1693 (CO), 1629 (C=N).
1H NMR: 2.20 (s, 3H, CH3), 2.21 (s, 3H, CH3), 2.41 (s, 3H, CH3), 6.46–7.02 (m, 5H), 9.32 (s, br., 1H, NH).
IR: 3268, 3246 (2 NH), 1677 (CO), 1624 (C=N).
1H NMR: 2.21 (s, 3H, CH3), 2.41 (s, 3H, CH3), 6.46–7.02 (m, 10H), 9.32 (s, br., 1H, NH), 10.23 (s, br., 1H, NH).
IR: 3177 (NH), 1695, 1680 (2 CO), 1602 (C=N).
1H NMR: 2.21 (s, 3H, CH3), 2.41 (s, 3H, CH3), 6.46–7.81 (m, 10H), 9.32 (s, br., 1H, NH).
IR: 3280 (NH), 1675 (CO), 1640 (C=N).
1H NMR: 2.21 (s, 3H, CH3), 2.41 (s, 3H, CH3), 6.46–7.59 (m, 10H), 9.32 (s, br., 1H, NH).
IR: 3290 (NH), 1680, 1651 (2 CO), 1630 (C=N).
1H NMR: 1.83 (m, 2H, CH2), 2.69 (m, 4H, CH2), 2.94 (m, 2H, CH2), 7.226–8.22 (m, 10H, aromatic protons), 9.32 (s, br.,
1H, NH).
MS: m/e = 483 (M+2, 0.6%), 481 (M+, 34%), 336 (14%), 296 (12%), 190 (10%), 145 (100%), 89 (58%).
IR: 3203 (NH), 1675, 1656 (2 CO).
12
1H NMR: 7.20–7.91 (m, 15 H, aromatic protons), 8.30 (s, 1H, pyrazole H-3), 9.51 (s, br., 1H, NH).
IR: 1744 (CO), 1620 (C=N), 1600 (C=C).
17a
1H NMR: 1.30 (t, 3H, J = 7.5 Hz, CH2CH3), 2.21 (s, 3H, CH3), 2.41 (s, 3H, CH3), 4.2 (q, 2H, J = 7.5 Hz, CH2CH3),
6.46–7.64 (m, 5H).
17b
17c
17d
17e
22
IR: 1702, 1651 (2 CO), 1620 (C=N).
1H NMR: 2.20 (s, 3H, CH3), 2.21 (s, 3H, CH3), 2.41 (s, 3H, CH3), 6.46–7.34 (m, 5H).
IR: 3393 (NH), 1673 (C=N).
1H NMR: 2.21 (s, 3H, CH3), 2.41 (s, 3H, CH3), 6.46–7.64 (m, 10H), 9.34 (s, br., 1H, NH).
IR: 1696 (CO), 1644 (C=N), 1596 (C=C).
1H NMR: 2.21 (s, 3H, CH3), 2.41 (s, 3H, CH3), 6.46–7.81 (m, 10H).
IR: 1744 (CO), 1620 (C=N), 1600 (C=C).
1H NMR: 2.21 (s, 3H, CH3), 2.41 (s, 3H, CH3), 6.46–7.78 (m, 10H).
IR: 3298, 3190 (NH2).
1H NMR: 3.25 (dd, 1H, J = 18.1, 5.8 Hz, CH (pyraz)), 3.82 ((dd, 1H, J = 18.1, 12.2 Hz, CH2 (pyraz)), 5.54 (dd, 1H, J = 12.2,
5.8 Hz, CH2 (pyraz)), 6.61 (s, 2H, NH2), 7.3–8.3 (m, 10H, aromatic protons).
IR: 3026, 2956 (CH), 1650 (C=N)
23a
23b
1H NMR: 2.47 (s, 3H, CH3), 3.25 (dd, 1H, J = 18.1, 5.8 Hz, CH (pyraz)), 3.82 ((dd, 1H, J = 18.1, 12.2 Hz, CH2 (pyraz)), 5.54
(dd, 1H, J = 12.2, 5.8 Hz, CH2 (pyraz)), 7.3–8.3 (m, 15H, aromatic protons).
IR: 3027, 2917 (CH), 1601 (C=N)
1H NMR: 3.25 (dd, 1H, J = 18.1, 5.8 Hz, CH (pyraz)), 3.82 ((dd, 1H, J = 18.1, 12.2 Hz, CH2 (pyraz)), 5.54 (dd, 1H, J = 12.2,
5.8 Hz, CH2 (pyraz)), 7.3–8.3 (m, 20H, aromatic protons).
MS: m/e = 527 (M+2, 3%), 526 (M+1, 11%), 525 (M+1, 34%), 420 (2%), 143 (15%), 129 (22%), 115 (17%), 103 (15%),
77 (100%).
23c
24a
24b
IR: 3030, 2971, 2930 (CH), 1625 (C=N)
1H NMR: 3.25 (dd, 1H, J = 18.1, 5.8 Hz, CH (pyraz)), 3.82 ((dd, 1H, J = 18.1, 12.2 Hz, CH2 (pyraz)), 5.54 ((dd, 1H, J = 12.2,
5.8 Hz, CH2 (pyraz)), 7.3–8.3 (m, 20H, aromatic protons).
IR: 3060, 2917 (CH), 1600 (C=C).
1H NMR: 2.47 (s, 3H, CH3), 3.25 (dd, 1H, J = 18.1, 5.8 Hz, CH (pyraz)), 3.82 ((dd, 1H, J = 18.1, 12.2 Hz, CH2 (pyraz)), 5.54
(dd, 1H, J = 12.2, 5.8 Hz, CH2 (pyraz)), 6.15 (s, 1H, thiazole H-5), 7.3–8.3 (m, 10H, aromatic protons).
IR: 3060, 2917 (CH), 1600 (C=C).
1H NMR: 3.25 (dd, 1H, J = 18.1, 5.8 Hz, CH (pyraz)), 3.82 ((dd, 1H, J = 18.1, 12.2 Hz, CH2 (pyraz)), 5.54 ((dd, 1H, J = 12.2,
5.8 Hz, CH2 (pyraz)), 6.11 (s, 1H, thiazole H-5), 7.3–8.3 (m, 15H, aromatic protons).
IR: 3247 (NH), 3047, 2948 (CH), 1619 (C=N).
26a
26b
1H NMR: 2.47 (s, 3H, CH3), 6.11 (s, 1H, thiazole H-5), 7.3–7.8 (m, 5H, aromatic protons), 9.32 (s, br,, 1H, NH).
IR: 3218 (NH), 3059, 2948 (CH), 1629 (C=N).
1H NMR: 1.13 (s, 3H, CH3), 2.47 (s, 3H, CH3), 6.11 (s, 1H), thiazole H-5), 7.4–7.8 (m, 10H, aromatic protons), 9.35 (s,
br., 1H, NH).
27a
27b
IR: 3420 (NH), 3057, 2949 (CH), 1604 (C=N).
1H NMR: 1.13 (s, 3H, CH3), 2.47 (s, 3H, CH3), 7.4–7.8 (m, 10H, aromatic protons), 9.32 (s, br., 1H, NH).
IR: 3422 (NH), 3058, 2935 (CH), 1605 (C=N).
1H NMR: 1.13 (s, 3H, CH3), 7.4–7.8 (m, 15H, aromatic protons), 9.32 (s, br., 1H, NH).
MS: m/e = 438 (M+1, 0.6%), 437 (M+, 0.54%), 405 (0.7%), 393 (5%), 158 (3.6%), 136 (5.8%), 135 (73%), 105 (58%),
90 (9%), 77 (100%).
27c
31a
31b
31c
31d
31e
IR: 3422 (NH), 3058, 2935 (CH), 1605 (C=N).
1H NMR: 1.13 (s, 3H, CH3), 7.4–7.8 (m, 15H, aromatic protons), 9.32 (s, br., 1H, NH).
IR: 1728 (CO), 1651 (CO) and 1596 (C=C).
1H NMR: 0.98 (t, 3H, J = 7.5 Hz, CH2CH3), 4.06 (q, 2H, J = 7.5 Hz, CH2CH3), 7.25–7.82 (m, 10H) and 8.29 (s,1H).
IR: 3331 (NH), 1681(CO), 1658(CO), 1627 (C=N) and 1596 (C=C).
1H NMR: 7.23–8.12 (m, 15H), 8.25 (s, 1H) and 9.25 (s, 1H).
IR: 1681(CO), 1658(CO), 1627 (C=N), 1596 (C=C).
1H NMR: 2.64 (s, 3H), 7.25–7.99 (m, 10H), 8.27 (s, 1H).
IR: 1651(CO), 1596 (C=C).
1H NMR: 7.23–8.12 (m, 15H), and 8.25 (s, 1H).
IR: 1651(CO), 1596 (C=C).
1H NMR: 7.23–8.12 (m, 15H), and 8.25 (s, 1H).
PAPER: 07/4804

JOURNaL OF ChEMICaL RESEaRCh 2007 615
Table 2 continued
Compd no.
Spectral data
33a
IR: 3330 (NH), 2923 (CH), 1674 (CO), 1596(C=C).
1H NMR: 7.33–7.62 (m, 10H), 8.23 (s, 1H), 11.12 (s, 1H).
MS: m/e = 329 (M+1, 18%), 328 (M+, 70%), 271 (39%), 113 (11%), 77 (100%).
IR: 1681(CO), 1627 (C=N), 1596 (C=C).
33b
1H NMR: 2.64 (s, 3H), 7.25–7.99 (m, 10H), 8.27 (s, 1H).
MS: m/e = 328 (M+2, 2.8%), 327 (M+1, 22%), 326 (M+, 90.52%), 284 (3%),256 (3%), 189 (3%), 182 (6%), 139 (6%),
104 (15%), 89 (15%), 77 (100%).
33c
33d
38a
IR: 1645 (C=N) and 1596 (C=C).
1H NMR: 7.23–8.12 (m, 15H), 8.25 (s, 1H).
IR: 1645 (C=N) and 1596 (C=C).
1H NMR: 7.23–8.12 (m, 15H), 8.35 (s, 1H).
IR: 3066, 2962 (CH),1739 (CO), 1627 (C=N), 1600 (C=C).
1H NMR: 1.24 (t, 3H, J = 7.5 Hz, CH2CH3), 2.50 (s, 3H), 4.09 (q, 2H, J = 7.5 Hz, CH2CH3), 5.62 (s, 1H), 7.05–8.47 (m,
15H, aromatic protones).
38b
38c
38d
IR: 3050, 2973 (CH), 1739 (CO), 1655 (C=N), 1607 (C=C).
1H NMR: 1.08 (d, 6H), 1.21 (t, 3H, J = 7.5 Hz, CH2CH3), 2.58 (s, 3H), 2.71 (sept., 1H), 4.06 (q, 2H, J = 7.5 Hz, CH2CH3),
5.62 (s, 1H), 7.03–8.51 (m, 14H).
IR: 3064, 2992 (CH), 1708 (CO), 1655 (C=N), 1610 (C=C).
1H NMR: 1.29 (t, 3H, J = 7.5 Hz, CH2CH3), 1.77 (s, 3H), 3.73 (s, 6H), 4.11 (q, 2H, J = 7.5 Hz, CH2CH3), 5.43 (s, 1H),
6.59–8.45 (m, 13H).
IR: 3064, 2979 (CH), 1691 (CO), 1654 (C=N), 1608 (C=C).
¹H NMR: 1.29 (t, 3H, J = 7.5 Hz, CH2CH3), 2.57 (s, 3H), 4.11 (q, 2H, J = 7.5 Hz, CH2CH3), 5.61 (s, 1H), 5.82 (s, 2H),
6.59–8.45 (m, 13H).
Methodꢀ B: an equimolar amount of the appropriate 2b, 13b or
39a–d (5 mmoles), the appropriate hydrazonoyl halides 1a–e
(5 mmoles) and sodium methoxide (0.27 g, 5 mmol) in ethanol
(20 ml) were heated under reflux for 4 h. The resulting solid was
collected and recrystallised from the proper solvent to give 6a–e,
17a–e and 38a–d, respectively (Tables 1 and 2).
Synthesisꢀ ofꢀ N-[1-benzofuran-2-ylethylidene]-N'-(4-substitutedꢀ
5-phenylazo-1,3-thiazol-2-yl)hydrazines 27a–c
Methodꢀ A: an equimolar amounts of 25 and the appropriate
hydrazonoyl halides 1b, 1d, 1e and triethylamine (5 mmoles)
in ethanol (20 ml) were heated under reflux for 4 h. The resulting
solid was collected and recrystallised from ethanol to give 27a–c,
respectively (Tables 1 and 2).
Methodꢀ B: benzene diazonium chloride was added to a cold
solution of the appropriate 26a or 26b (5 mmoles) in pyridine (20 ml)
while stirring. The crude solid was collected and recrystallised from
ethanol to give 27a and 27b, respectively (Tables 1 and 2).
Synthesisꢀ ofꢀ 3-(1-benzofuran-2-ylcarbonyl)-5-phenyl-4,5-dihydro-
1H-pyrazol-1-carbothioamide (22)
a mixture of 1(1-benzofuran-2-yl)-3-phenylpropenone (20) (2.48 g,
10 mmoles) and thiosemicarbazide (21) (1 g, 10 mmoles) in acetic
acid (25 ml) was heated under reflux for 6 h. The resulting solid that
obtained after cooling was collected and recrystallised from acetic
acid to give 22 (Tables 1 and 2).
Synthesisꢀ ofꢀ 1-phenyl-4-(1-benzofuran-2-ylcarbonyl)-3-substitutedꢀ
pyrazolesꢀ31a–e
an equimolar amounts of the appropriate hydrazonoyl halides 1a–e,
1-(benzofuran-2-yl)-3-(dimethylamino)prop-2-en-1-one (28) and
triethylamine (5 mmoles) in toluene (20 ml) were heated under
reflux for 2 h. The solvent was evaporated under reduce pressure and
triturated with petroleum ether 40–60°C then the resulting solid was
collected and recrystallised from ethanol to give the pyrazoles 31a–e,
respectively (Tables 1 and 2).
Synthesisꢀ ofꢀ 1-{[2-(1-benzofuran-2-yl)-5-phenyl-4,5-dihydro-1H-
pyrazol-1-yl]-4-substitutedꢀ1,3-thiazol-5-yl}-2-phenyldiazene 23a–c
Methodꢀ A: a mixture of 22 (1.60 g, 5 mmoles), the appropriate
hydrazonoyl halides 6b, 6d, 6e (5 mmoles) and triethylamine (0.5 g,
0.75 ml, 5 mmoles) in ethanol (20 ml) was heated under relux for
4 h. The resulting solid was collected and recrystallised from ethanol
to give 23a–c, respectively (Tables 1 and 2).
Methodꢀ B: benzene diazonium chloride was added to a cold
solution of the appropriate 24a or 24b (5 mmoles) in pyridine (20 ml)
while stirring. The crude solid was collected and recrystallised from
ethanol to give 23a and 23b, respectively.
MethodꢀC: Sodium hydroxide solution (100 ml, 10%) was added
dropwise to equimolar amounts of the appropriate 27a or 27b and
benzaldehyde in ethanol (20 ml) while stirring at room temperature.
The reaction mixture was stirred for 4 h and the resulting solid
was collected and recrystallised from ethanol to give 23a and 23b,
respectively.
Synthesisꢀ ofꢀ 7-(1-benzofuran-2-yl)-2-phenyyl-2H-4-substitutedꢀ
pyrazolo[3,4-d]pyridazines 33a–d
an equimolar amounts of the appropriate pyrazoles 31a–e and
hydrazine hydrate (5 mmoles) in ethanol (20 ml) was boiled under
refluxed for 2 h. The resulting solid was collected and recrystallised
from the proper solvent to give the pyrazolo[3,4-d]pyridazines 33a–c,
respectively (Tables 1 and 2).
Receivedꢀ21ꢀAugustꢀ2007;ꢀacceptedꢀ30ꢀOctoberꢀ2007ꢀ
Paperꢀ07/4804ꢀ
doi:ꢀ10.3184/030823407X256118
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pyrazol-1-yl]-4-substitutedꢀ1,3-thiazoleꢀ24a and 24b
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8
9
Synthesisꢀ ofꢀ N-[1-benzofuran-2-ylethylidene]-N’-(4-substitutedꢀ 1,3-
thiazol-2-yl)hydrazine 26a and 26b
Equimolar amounts of 2-acetylbezofuranthisemicarbazone (25) and
the appropriate chloroacetone or ω-bromoacetophenone (5 mmoles)
in ethanol (20 ml) was boiled under refux for 2 h. The resulting solid
was collected and recrystallised from ethanol to give 26a and 26b,
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PAPER: 07/4804

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PAPER: 07/4804