Synthesis of some new thiazoles and pyrazolo[1,5-a]pyrimidines containing an antipyrine moiety

Article abstract of DOI:10.1080/00397910903100726

Ethyl 2-{2-[4-(2,3-dimethyl-5-oxo-1-phenyl-3-(pyrazolin-4-yl)]-2-cyano-1- (phenylamino)vinylthio}-acetate, 2-[4-(2,3-dimethyl-5-oxo-1-phenyl-(3-pyrazolin- 4-yl))(1,3-thiazol-2-yl)]2-(4-oxo-3-phenyl-(1,3-thiazoilidin-2-ylidene)) ethanenitrile, 2-[4-(2,3-dimethyl-5-oxo-1-phenyl(3-pyrazolin-4-yl))(1,3-thiazol- 2-yl)]-2-(4-methyl-3-phenyl(1,3-thiazolin-2-ylidene))ethanenitrile, 2-(5-acetyl-4-methyl-3-phenyl(1,3-thiazolin-2-ylidene))-2-[4-(2, 3-dimethyl-5-oxo-1-phenyl(3-pyrazolin-4-yl))(1,3-thiazol-2-yl)]ethanenitrile, and ethyl 2-(cyano(4-(2,3-dihydro-1,5-dimethyl-3-oxo-2-phenyl-1H-pyrazol-4-yl) thiazol-2-yl)methylene)-2,3-dihydro-4-methyl-3-phenylthiazole-5-carboxylate were synthesized by treatment of 2-(4-(2,3-dihydro-1,5-dimethyl-3-oxo-2-phenyl-1H- pyrazol-4-yl)thiazol-2-yl)-3-mercapto-3-(phenylamino)-acrylonitrile with appropriate halo ketones or halo esters. Also, 4-{2-[5,7-dimethyl-2- (phenylamino)(7a-hydropyrazolo[1,5-a]pyrimidin-3-yl](1,-thiazol-4-yl)}-2, 3-dimethyl-1-phenyl-3-pyrazolin-5-one derivatives were synthesized via reaction of 4-{2-[5-amino-3-(phenylamino)pyrazolin-4-yl](1,3-thiazol-2-yl)}-2,3-dimethyl- 1-phenyl-3-pyrazolin-5-one with-diketone or-keto ester. All synthesized compound were established by elemental analysis, spectral data, and alternative synthesis whenever possible. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/00397910903100726

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Synthesis of Some New Thiazoles and
Pyrazolo[1,5-a]pyrimidines Containing
an Antipyrine Moiety
Abdou O. Abdelhamid a & Mamdouh A. M. Afifi a
a Department of Chemistry, Faculty of Science, Cairo University,
Giza, Egypt
Published online: 23 Apr 2010.
To cite this article: Abdou O. Abdelhamid & Mamdouh A. M. Afifi (2010) Synthesis of Some New
Thiazoles and Pyrazolo[1,5-a]pyrimidines Containing an Antipyrine Moiety, Synthetic Communications:
An International Journal for Rapid Communication of Synthetic Organic Chemistry, 40:10, 1539-1550,
DOI: 10.1080/00397910903100726
To link to this article: http://dx.doi.org/10.1080/00397910903100726
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Synthetic Communications1, 40: 1539–1550, 2010
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397910903100726
SYNTHESIS OF SOME NEW THIAZOLES AND
PYRAZOLO[1,5-a]PYRIMIDINES CONTAINING AN
ANTIPYRINE MOIETY
Abdou O. Abdelhamid and Mamdouh A. M. Afifi
Department of Chemistry, Faculty of Science, Cairo University,
Giza, Egypt
Ethyl 2-{2-[4-(2,3-dimethyl-5-oxo-1-phenyl-3-(pyrazolin-4-yl)]-2-cyano-1-(phenylamino)
vinylthio}-acetate, 2-[4-(2,3-dimethyl-5-oxo-1-phenyl-(3-pyrazolin-4-yl))(1,3-thiazol-2-yl)]-
2-(4-oxo-3-phenyl-(1,3-thiazoilidin-2-ylidene))ethanenitrile, 2-[4-(2,3-dimethyl-5-oxo-1-
phenyl(3-pyrazolin-4-yl))(1,3-thiazol-2-yl)]-2-(4-methyl-3-phenyl(1,3-thiazolin-2-ylidene))
ethanenitrile, 2-(5-acetyl-4-methyl-3-phenyl(1,3-thiazolin-2-ylidene))-2-[4-(2,3-dimethyl-
5-oxo-1-phenyl(3-pyrazolin-4-yl))(1,3-thiazol-2-yl)]ethanenitrile, and ethyl 2-(cyano
(4-(2,3-dihydro-1,5-dimethyl-3-oxo-2-phenyl-1H-pyrazol-4-yl)thiazol-2-yl)methylene)-2,
3-dihydro-4-methyl-3-phenylthiazole-5-carboxylate were synthesized by treatment of 2-
(4-(2,3-dihydro-1,5-dimethyl-3-oxo-2-phenyl-1H-pyrazol-4-yl)thiazol-2-yl)-3-mercapto-3-
(phenylamino)-acrylonitrile with appropriate halo ketones or halo esters. Also, 4-{2-[5,
7-dimethyl-2-(phenylamino)(7a-hydropyrazolo[1,5-a]pyrimidin-3-yl](1,-thiazol-4-yl)}-2,
3-dimethyl-1-phenyl-3-pyrazolin-5-one derivatives were synthesized via reaction of 4-{2-[5-
amino-3-(phenylamino)pyrazolin-4-yl](1,3-thiazol-2-yl)}-2,3-dimethyl-1-phenyl-3-pyrazolin-
5-one with b-diketone or b-keto ester. All synthesized compound were established by elemental
analysis, spectral data, and alternative synthesis whenever possible.
Keywords: Antipyrine; coumarine; pyrazoles; pyrazolo[1,5-a]pyrimidines; thiazoles
INTRODUCTION
Broad spectra of bioactive antipyrine derivatives have been investigated and
diverse bioactivities such as analgesic,[1,2] anti-inflammatory,[3] antimicrobial,[4–6]
and anticancer[7] activity have been reported. Also, a large number of thiazole deri-
vatives have been found to exhibit pharmacological activity.[8–13] As an extension of
our study[14–18] and as a part of our program aiming at the synthesis of different
thiazoles for medicines, we report herein the synthesis of some new thiazoles and
pyrazolo[1,5-a]pyrimidines containing an antipyrine moiety.
Received May 23, 2009.
Address correspondence to Abdou O. Abdelhamid, Department of Chemistry, Faculty of Science,
Cairo University, Giza 12613, Egypt. E-mail: Abdelhamid45@gmail.com
1539

1540
A. O. ABDELHAMID AND M. A. M. AFIFI
RESULTS AND DISCUSSION
Treatment of 2-[4-(2,3-dimethyl-5-oxo-1-phenyl-3-pyrazolin-4-yl)-1,3-thiazol-
2-yl]ethanenitrile[19] (1) with the appropriate of 4-methylbenzenediazonium chloride,
benzaldehyde, or salicylaldehyde to give [4-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-
1H-pyrazol-4-yl)thiazol-2-yl]-(N0-4-tolylhydrazino)-acetonitrile (2), [4-(1,5-dimethyl-3-
oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)thiazol-2-yl]-3-phenylacrylonitrile (4) and
4-[2-(2-imino-2H-chromen-3-yl)-thiazol-4-yl]-1,5-dimethyl-2-phenyl-1,2-dihydro-
pyrazol-3-one (8), respectively. Compound 8 was converted to 3-[4-(2,3-dimethyl-5-
oxo-1-phenyl-3-pyrazolin-4-yl)-1,3-thiazol-2-yl]-2H-chromen-2-one (9) by hydrolysis
with hydrochloric acid (Scheme 1).
Structures 2 and 4 were elucidated by elemental analysis, spectral data, alterna-
1
tive synthetic routes, and chemical transformation. H NMR spectrum of 2 showed
signals at d ¼ 2.42 (s, 3H, CH3), 2.76 (s, 3H, CH3), 3.20 (s, 3H, CH3), 7.26–7.52 (m,
10H, ArH’s and NH proton) and 8.16 (s, 1H, thiazole H-5). Its infrared (IR) spectra
=
revealed bands at 3417 (NH), 2206 (CN), 1681 (CO), 1620 (C N). Thus, treatment
of 4-(chloroacetyl)antipyrine with 2-cyano-2-(4-tolyhydrazono)thioacetamide (3)
and 2-cyano-3-phenylthioacrylamide (5) in boiling acetic acid gave products ident-
ical in all respects (mp, mixed mp, and spectra) to 2 and 4, respectively. Compound
2 reacted with x-bromoacetophenone in boiling N,N-dimethylformamide containing
potassium carbonate and triethylamine to give 4-{2-[4-amino-1-(4-methylphenyl)-5-
phenylcarbonyl)pyrazol-3-yl](1,3-thiazol-4-yl)}-2,3-dimethyl-1-phenyl-3-pyrazolin-
5-one (6). Structure 6 was confirmed by elemental analysis and spectral data. IR
=
spectrum of 6 revealed bands at 3463, 3355 (NH2), 1681 (CO), and 1600 (C C).
1
Its H NMR showed signals at d ¼ 2.42 (s, 3H, CH3), 2.74 (s, 3H, CH3), 3.21 (s,
3H, CH3), 6.23 (s, br., 2H, NH2), 7.21–7.52 (m, 14H, ArH’s), and 8.05 (s, 1H,
Scheme 1. Synthesis of 4-aminopyrazoles 6 and 4-substituted coumarine 9.

NEW THIAZOLES AND PYRAZOLO[1,5-a]PYRIMIDINES
1541
thiazole H-5). Meanwhile, compound 1 reacted with either (phenylmethylene)-
methane-1,1-dicarbonitrile or ethyl 2-cyano-3-phenylprop-2-enoate in boiling etha-
nol containing a catalytic amount of piperidine to yield 4. The reaction that takes
place is 1,4-Michael addition followed by a tautomerization to form the intermediate
7, which readily loses one molecule of malononitrile or ethyl cyanoacetate.
Treatment of thioamide 10, synthesized via reaction of 1 with phenyl isothio-
cyanate in the presence of potassium hydroxide, with ethyl chloroacetate in the
presence of potassium hydroxide gives ethyl 2-{2-[4-(2,3-dimethyl-5-oxo-1-phenyl-
3-(pyrazolin-4-yl)]-2-cyano-1-(phenylamino)vinylthio}acetate (11) (Scheme 2). Com-
pound 11 was elucidated by elemental analysis, spectra, and chemical transform-
1
ation. H NMR spectrum of 11 showed signals at d ¼ 1.24 (t, 3H, CH2CH3), 2.55
(s, 3H, CH3), 3.15 (s, 3H, CH3), 3.32 (s, 2H SCH2), 4.13 (q, 2H, CH2CH3),
7.27–7.52 (m, 11H, ArH’s and NH proton), and 8.09 (s, 1H, thiazole H-5). IR
=
spectrum reveled bands at 3182 (NH), 2198 (CN), 1726 (CO), 1654 (C N), 1593
=
(C C). Compound 11, when boiled with ethanol containing catalytic amounts of
piperidine, gave 2-[4-(2,3-dimethyl-5-oxo-1-phenyl-(3-pyrazolin-4-yl))(1,3-thiazol-2-
yl)]-2-(4-oxo-3-phenyl-(1,3-thiazoilidin-2-ylidene))ethanenitrile (12). Treatment of
10 with chloroacetylchloride in N,N-dimethylformamide containing potassium
hydroxide gave a product identical in all respects (mp, mixed mp., spectra) with 12.
Analogously, treatment of 10 with either chloroacetone or x-bromoacetophe-
none in N,N-dimethylformamide containing potassium hydroxide gave 2-(4-(2,
3-dihydro-1,5-dimethyl-3-oxo-2-phenyl-1H-pyrazol-4-yl)thiazol-2-yl)-2-(4-methyl-3-
phenylthiazol-2(3H)-ylidene)acetonitrile (14a) and 2-(4-(2,3-dihydro-1,5-dimethyl-3-
oxo-2-phenyl-1H-pyrazol-4-yl)thiazol-2-yl)-2-(3,4-diphenylthiazol-2(3H)-ylidene)
Scheme 2. Synthesis of some thiazoles 12, 14–16.

1542
A. O. ABDELHAMID AND M. A. M. AFIFI
acetonitrile (14b), respectively. Structures 14a and 14b were elucidated by elemen-
tal analysis and spectral data (cf. Experimental section).
Also, compound 10 reacted with either 3-chloro-2,4-pentanedione, ethyl 2-
chloro-3-oxobutanoate, or iodomethane in N,N-dimethylformamide containing
potassium hydroxide to afford 2-(5-acetyl-4-methyl-3-phenyl(1,3-thiazolin-2-
ylidene))-2-[4-(2,3-dimethyl-5-oxo-1-phenyl(3-pyrazolin-4-yl))(1,3-thiazol-2-yl)]etha-
nenitrile (15), ethyl 2-(cyano(4-(2,3-dihydro-1,5-dimethyl-3-oxo-2-phenyl-1H-
pyrazol-4-yl)thiazol-2-yl)methylene)-2,3-dihydro-4-methyl-3-phenylthiazole-5-carbox-
ylate (16), and 2-[4-(2,3-dimethyl-5-oxo-1-phenyl(3-pyrazolin-4-yl))(1,3-thiazol-
2-yl)]-3-methylthio-3-(phenylamino)prop-2-enenitrile (17), respectively. Structures
15 and 16 were confirmed by elemental analysis and spectral data. Thus, 1H
NMR spectrum of 15 showed signals at d ¼ 2.28 (s, 3H, CH3), 2.52 (s, 3H, CH3),
2.98 (s, 3H, CH3), 3.21 (s, 3H, CH3), 7.25–7.66 (m, 10H, ArH’s), and 8.03 (s, 1H,
=
thiazole 5-H). Its IR revealed bands at 2187 (CN), 1656 (CO), 1633 (C N), and
1
=
1587 (C C). H NMR spectrum of 16 showed signals at d ¼ 1.41 (t, 3H, CH2CH3),
2.10 (s, 3H, CH3), 2.96 (s, 3H, CH3), 3.20 (s, 3H, CH3), 4.35 (q, 2H, CH2CH3),
7.25–6.67 (m, 10H, ArH’s), and 8.02 (s, 1H, thiazole H-5). Its IR revealed bands
=
at 2183 (CN), 1705, 1658 (CO’s), and 1596 (C C).
Treatment of 17 with hydrazine hydrate in boiling ethanol gave 4-{2-[5-
amino-3-(phenylamino)pyrazolin-4-yl](1,3-thiazol-2-yl)}-2,3-dimethyl-1-phenyl-3-
pyrazolin-5-one (18) (Scheme 3). Structure 18 was elucidated by elemental analysis,
spectral data, and chemical transformation. Thus, 18 reacted with 2,4-pentanedione
Scheme 3. Synthesis of some pyrazolo[1,5-a]pyrimidines 19, 21, and 23.

NEW THIAZOLES AND PYRAZOLO[1,5-a]PYRIMIDINES
1543
in boiling acetic acid to give 4-{2-[5,7-dimethyl-2-(phenylamino)(7a-hydropyra-
zolo[1,5-a]pyrimidin-3-yl](1,-thiazol-4-yl)}-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one
(19). Structure 19 was confirmed on the basis of elemental analysis and spectral data.
Thus, 1H NMR spectrum of 19 showed signals at d ¼ 2.56 (s, 3H, CH3), 2.67 (s, 3H,
CH3), 2.87 (s, 3H, CH3), 3.16 (s, 3H, CH3), 6.12 (s, 1H, pyrimidine H-5), 7.0–7.95
(m, 11H, ArH’s and thiazole H-5), and 9.75 (s, 1H, NH). Its IR spectrum revealed
=
bands at 3301 (NH), 1639 (C N), and 1602 (C C).
=
Similarly, 18 reacted with either ethyl acetoacetate or ethyl benzoylacetate in
acetic acid to afford 3-[4-(2,3-dimethyl-5-oxo-1-phenyl(3-pyrazolin-4-yl))(1,3-thiazol-
2-yl)]-7-methyl-2-(phenylamino)-4,6,7,7a-tetrahydropyrazolo[1,5-a]-pyrimidin-5-one
(21a) and 3-[4-(2,3-dimethyl-5-oxo-1-phenyl(3-pyrazolin-4-yl))(1,3-thiazol-2-yl)]-7-
phenyl-2-(phenylamino)-4,6,7,7a-tetrahydropyrazolo[1,5-a]-pyrimidin-5-one (21b),
respectively. Structures 21 were elucidated by elemental analysis, spectral data,
and alternative synthetic routes. 1H NMR spectrum of 21a showed signals at
d ¼ 2.35 (s, 3H, CH3), 2.57 (s, 3H, CH3), 3.06 (s, 3H, CH3), 8.67 (s, 2H, 2 NH),
5.60 (s, 1H, pyrimidine H-5), 6.87–7.450 (m, 10H, ArH’s), and 8.01 (s, thiazole
=
H-5). Its IR spectrum revealed bands at 3350 (NH), 1687 (CO), 1643 (C N), and
=
1610 (C C). Molecular orbital calculation (using Hyper-Chem., semi-empirical
Method AM1) indicated that the structure 21 is more stable than structure 20.
Compound 18 reacted with acetoacetanilide or benzoylacetanilide to afford
products identical in all aspects (mp, mixed mp, and spectra) to 21a and 21 b.
Also, compound 18 reacted with 2-benzylidenemalononitrile in boiling ethanol
to afford 7-amino-3-[4-(2,3-dimethyl-5-oxo-1-phenyl(3-pyrazolin-4-yl))(1,3-thiazol-
2yl)]-5-phenyl-2(phenylamino)-7a-hydropyrazolo[1,5-a]pyrimidine-6-carbonitrile (23).
The structure of 23 was confirmed by elemental analysis, alternate synthetic route,
1
and spectral data. H NMR spectra of 23 showed signals at d ¼ 2.92 (s, 3H, CH3),
3.28 (s, 3H, CH3), 7.25–7.61 (m, 15H, ArH’s), 8.00 (s, 1H, thiazol H-5), 8.95 (s,
br., 2H, NH2), 9.75 (s, br., 1H, NH). Thus, treatment of 4-{2-[5-(1-aza-2-
phenylvinyl)-3-(phenylamino)pyrazol-4-yl](1,3-thiazol-2-yl)}-2,3-dimethyl-1-phenyl-
3-pyrazolin-5-one (24a), which was prepared via reaction of 18 with benzaldehyde in
ethanolic sodium ethoxide, with malononitrile gave a product identical in all respects
(mp, mixed mp, and spectra) to 23.
EXPERIMENTAL
All melting points were determined on an electrothermal apparatus and are uncor-
rected. IR spectra were recorded (KBr discs) on a Shimadzu Fourier transform (FT)–IR
1
8201 PC spectrophotometer. H NMR and spectra were recorded in CDCl3 and
(CD3)2SO solutions on a Varian Gemini 300-MHz spectrometer, and chemical shifts
are expressed in d units using tetramethylsilane (TMS) as an internal reference. Elemen-
tal analyses were carried out at the Microanalytical Center of the Cairo University.
[4-(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-
4-yl)thiazol-2-yl]-(N0-tolylhydrazino)-acetonitrile (2)
Method A. A solution of the appropriate 4-methylbenzenediazonium chloride
(0.01 mol.) was added to a solution of 1 (3.1 g, 0.01 mol) and sodium acetate (1.3 g,

1544
A. O. ABDELHAMID AND M. A. M. AFIFI
0.01 mol) in ethanol (30 ml) at 0–5 ꢀC while stirring, and the reaction mixture was
stirred for 6 h at 0 ꢀC. The resulting solid was collected and recrystallized from acetic
acid to give yellow crystals; mp 249–251 ꢀC, yield (92%); IR (cmꢁ1): 3417 (NH), 2206
1
=
(CN), 1681 (CO), 1620 (C N). H NMR (CD3Cl) d ¼ 2.42 (s, 3H, CH3), 2.76 (s, 3H,
CH3), 3.20 (s, 3H, CH3), 7.26–7.52 (m, 10H, ArH’s and NH proton), and 8.16 (s, 1H,
thiazole H-5). Anal. calcd. for C23H20N6OS (428.52): C, 64.47; H, 4.70; N, 19.61; S,
7.48. Found: C, 64.35, H; 4.67; N, 19.52; S, 7.58.
Method B. A mixture of 4-chloroacetylantipyrine (2.6 g, 0.01 mol) and 4-toly-
lazocyanothioacetamide (2.18 g, 0.01 mol) in ethanol (20 ml) was heated under reflux
for 2 h. The resulting solid was collected, washed with boiling water containing
sodium acetate, and recrystallized from dimethylformamide to give 2.
Synthesis of 4 and 8
Method A. An equimolar amount of 1 and either benzaldehyde or salicylal-
dehde (5 mmol) in 20 ml ethanol containing a catalytic amount of sodium ethoxide
was stirred for 2 h. The resulting solid was collected and recrystallized from acetic
acid to give 4 and 8, respectively.
Method B. A mixture of 4-chloroacetylantipyrine (2.6 g, 0.01 mol) and
2-cyano-phenylthioacrylamide (1.88 g, 0.01 mol) in acetic acid (20 ml) was heated
under reflux for 2 h. The resulting solid was collected, washed with boiling water
containing sodium acetate, and recrystallized from dimethylformamide to give 4.
[4-(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-
4-yl)thiazol-2-yl]-3-phenylacrylonitrile (4)
This compound was obtained as pale yellow crystals (AcOH), mp 195 ꢀC, yield
1
(78%); IR (cmꢁ1): 2216 (CN), 1662 (CO), 1600 (C C). H NMR (CD3)2SO d ¼ 2.44
=
(s, 3H, CH3), 2.84 (s, 3H, CH3), 6.95–7.99 (m, 10H, ArH’s), 8.07 (s, 1H, thiazole
H-5), 8.74 (s, 1H, CH ¼). Anal. calcd. for C23H18N4OS (398.49): C, 69.33; H,
4.55; N, 14.06; S, 8.05. Found: C, 69.22, H; 4.45; N, 13.85; S, 8.11.
4-[2-(2-Imino-2H-chromen-3-yl)-thiazol-4-yl]-1,5-dimethyl-2-phenyl-
1,2-dihydropyrazol-3-one (8)
This compound was obtained as pale-yellow crystals (DMF); mp 240–242 ꢀC,
1
yield (76%); IR (cmꢁ1): 3240 (NH), 1662 (CO), 1643 (C N), 1596 (C C). H NMR
(CD3Cl) d ¼ 2.44 (s, 3H, CH3), 2.84 (s, 3H, CH3), 6.95–7.99 (m, 10H, ArH’s), 8.07 (s,
1H, thiazole H-5), 9.25 (s, br., 1H, NH). Anal. calcd. for C23H18N4O2S (414.49): C,
66.65; H, 4.38; N, 13.52; S, 7.74. Found: C, 66.56, H; 4.35; N, 13.42; S, 7.82.
=
=
3-[4-(2,3-Dimethyl-5-oxo-1-phenyl-3-pyrazolin-4-yl)-1,3-thiazol-2-
yl]-2H-chromen-2-one (9)
A mixture of 8 (1 g, 0.0025 mol) and hydrochloric acid (10 ml, 3 M) was
warmed with stirring for 30 min. The resulting solid was collected, washed with

NEW THIAZOLES AND PYRAZOLO[1,5-a]PYRIMIDINES
1545
water, and recrystallized from ethanol to give pale-yellow crystals (EtOH); mp
ꢁ1
260–262 ꢀC, yield (67%); IR (cm ): 1702, 1662 (CO’s), 1643 (C N), 1589 (C C).
1H NMR (CD3)2SO d ¼ 2.44 (s, 3H, CH3), 2.84 (s, 3H, CH3), 6.95–7.99 (m, 10H,
ArH’s), 8.07 (s, 1H, thiazole H-5). Anal. calcd. for C23H17N3O3S (415.47): C,
66.49; H, 4.12; N, 10.11; S,7.72. Found: C, 66.52, H; 4.12; N, 10.21; S, 7.65.
=
=
4-{2-[4-Amino-1-(4-methylphenyl)-5-phenylcarbonyl)pyrazol-
3-yl](1,3-thiazol-4-yl)}-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one (6)
A mixture of 2 (4.27 g, 0.01 mol) and x-bromoacetophenone (0.01 mol) in
DMF (20 ml) containing anhydrous potassium carbonate (0.01 mol) was refluxed
in an oil bath at 130 ꢀC for 3 h. The mixture was cooled, triethylamine (1 ml) was
added, and the mixture was refluxed for 1 h at 90 ꢀC. Then the reaction mixture
was poured into an ice-water mixture (100 ml). The resulting solid was collected
and recrystallized from proper sꢁo1lvent to give pale-yellow crystals (AcOH); mp
238–240 ꢀC, yield (69%); IR (cm ): 3463, 3355 (NH2), 1681 (CO), 1600 (C C).
=
1H NMR (CD3)2SO d ¼ 2.42 (s, 3H, CH3), 2.74 (s, 3H, CH3), 3.21 (s, 3H, CH3),
6.23 (s, br., 2H, NH2), 7.21–7.52 (m, 14H, ArH’s), 8.05 (s, 1H, thiazole H-5). Anal.
calcd. for C31H26N6O2S (546.66): C, 8.11; H, 4.79; N, 15.37; S,5.87. Found: C, 68.14,
H; 4.87; N, 15.42; S, 5.76.
Ethyl 2-{2-[4-(2,3-Dimethyl-5-oxo-1-phenyl-3-(pyrazolin-4-yl)]-
2-cyano-1-(phenyl-amino)vinylthio}acetate (11)
A mixture of 10 (4.45 g, 10 mmol) and potassium hydroxide (0.6 g, 10 mmol) in
N,N-dimethylformamide (20 mL) was stirred for 2 h at room temperature. Ethyl
chloroacetate (10 mmol) was added, and stirring was continued for 2 h. The resulting
solid was collected and recrystallized with acetic acid to give pale-yellow crystals
(EtOH); mp 230–232 ꢀC, yield (60%); IR (cmꢁ1): 3182 (NH), 2198 (CN), 1726
1
=
=
(CO), 1654 (C N), 1593 (C C). H NMR (CD3)2SO d ¼ 1.24 (t, 3H, CH2CH3),
2.55 (s, 3H, CH3), 3.15 (s, 3H, CH3), 3.32 (s, 2H SCH2), 4.13 (q, 2H, CH2CH3),
7.27–7.52 (m, 11H, ArH’s and NH proton) and 8.09 (s, 1H, thiazole H-5). Anal.
calcd. for C27H25N5O3S2 (531.66): C, 61.13; H, 4.74; N, 13.17; S, 12.06. Found: C,
61.13, H; 4.85; N, 13.00; S, 12.10.
2-[4-(2,3-Dimethyl-5-oxo-1-phenyl-(3-pyrazolin-4-yl))(1,3-thiazol-2-
yl)]-2-(4-oxo-3-phenyl-(1,3-thiazoilidin-2-ylidene))ethanenitrile (12)
Method A. A solution of 11 (2.65 g, 5 mmol) in ethanol (20 mL) containing
piperidine (0.3 mL) was heated under reflux for 2 h. After cooling, the resulting solid
was collected by filtration and recrystallized from N,N-dimethylformamide to give
pale-yellow crystals (DMF); mp 255–257 ꢀC, yield (62%); IR (cmꢁ1): 2166 (CN),
1
=
=
1662 (CO), 1618 (C N), 1590 (C C). H NMR (CD3)2SO d ¼ 2.49 (s, 3H, CH3),
2.97 (s, 3H, CH3), 3.68 (s, 2H, CH2 thiazoline), 7.13–7.60 (m, 10H, ArH’s), 8.07
(s, 1H, thiazole H-5). Anal. calcd. for C25H19N5O2S2 (485.59): C, 61.84; H, 3.94;
N, 14.42; S,13.21. Found: C, 61.76, H; 4.10; N, 14.32; S, 13.22.

1546
A. O. ABDELHAMID AND M. A. M. AFIFI
Method B. A mixture of 10 (4.45 g, 10 mmol) and potassium hydroxide (0.6 g,
10 mmol) in N,N-dimethylformamide (20 mL) was stirred for 2 h at room tempera-
ture. Chloroacetyl chloride (10 mmol) was added, and stirring continued for 2 h.
The resulting solid was collected and recrystallized with N,N-dimethylformamide
to give 12.
Synthesis of 14a,b and 15–17
A mixture of 10 (4.45 g, 0.01 mol) and potassium hydroxide (0.6 g, 0.01 mol) in
N,N-dimethylformamide (20 mL) was stirred for 2 h at room temperature.
Chloroacetone, x-bromoacetophenone, 3-chloro-2,4-pentandione, ethyl 2-chloro-3-
oxobutanoate, or iodomethane (0.01 mol each) was added, and stirring was
continued for 2 h. The resulting solid was collected and recrystallized from the
proper solvent to give 14a, 14b, 15, 16, or 17, respectively.
2-[4-(2,3-Dimethyl-5-oxo-1-phenyl(3-pyrazolin-4-yl))(1,3-thiazol-2-yl)]-2-
(4-methyl-3-phenyl(1,3-thiazolin-2-ylidene))ethanenitrile (14a). This com-
pound was obtained as pale yellow crystals (AcOH); mp 312–14 ꢀC, yield (60%);
1
IR (cmꢁ1): 2186 (CN), 1654 (C N), 1593 (C C). H NMR (CD3)2SO d ¼ 1.90 (s,
3H, CH3), 2.90 (s, 3H, CH3), 3.17 (s, 3H, CH3), 6.52–7.60 (m, 10H, ArH’s), 7.92
(s, 2H, 2 thiazole H-5). Anal. calcd. for C26H21N5OS2 (483.62): C, 64.57; H, 4.38;
N, 14.48; S, 13.26. Found: C, 64.74, H; 4.26; N, 14.35; S, 13.42.
=
=
2-[4-(2,3-Dimethyl-5-oxo-1-phenyl(3-pyrazolin-4-yl))(1,3-thiazol-2-yl)]-2-
(3,4-diphenyl(1,3-thiadiazolin-2- ylidene)ethanenitrile (14b). This compound
was obtained as pale yellow crystals (AcOH); mp 310–312 ꢀC, yield (60%); IR
1
(cmꢁ1): IR: 2173 (CN), 1651 (C N), 1614, 1593 (C C). H NMR (CD3)2SO
d ¼ 2.93 (s, 3H, CH3), 3.19 (s, 3H, CH3), 6.54–7.47 (m, 15H, ArH’s), 7.95 (s, 2H,
2 thiazole H-5). Anal. calcd. for C31H23N5OS2 (545.69): C, 68.23; H, 4.25; N,
12.83; S, 11.75. Found: C, 68.41, H; 4.12; N, 12.74; S, 11.53.
=
=
2-(5-Acetyl-4-methyl-3-phenyl(1,3-thiazolin-2-ylidene))-2-[4-(2,3-dimethyl-
5-oxo-1-phenyl(3-pyrazolin-4-yl))(1,3-thiazol-2-yl)]ethanenitrile
(15). This
compound was obtained as pale yellow crystals (AcOH); mp 346–349 ꢀC, yield
1
(62%); IR (cmꢁ1): IR: 2187 (CN), 1656 (CO), 1633 (C N), 1587 (C C). H NMR
(CD3)2SO d ¼ 2.28 (s, 3H, CH3), 2.52 (s, 3H, CH3), 2.98 (s, 3H, CH3), 3.21 (s, 3H,
CH3), 7.25–7.66 (m, 10H, ArH’s), 8.03 (s, 1H, thiazole 5-H) Anal. calcd. for
C28H23N5OS2 (525.66): C, 63.98; H, 4.41; N, 13.32; S, 12.20. Found: C, 63.34, H;
4.34; N, 13.25; S, 12.10.
=
=
Ethyl 2-{[4-(2,3-Dimethyl-5-oxo-1-phenyl(3-pyrazolin-4-yl))(1,3-thiazol-2-
yl)]cyano-methylene}-4-methyl-3-phenyl-1,3-thiazoline-5-carboxylate (16). This
compound was obtained as pale yellow crystals (AcOH); mp 307–309 ꢀC, yield
1
(63%); IR (cmꢁ1): 2183 (CN), 1705, 1658 (CO’s), 1596 (C C). H NMR (CD3)2SO
=
d ¼ 1.41 (t, 3H, CH2CH3), 2.10 (s, 3H, CH3), 2.96 (s, 3H, CH3), 3.20 (s, 3H, CH3),
4.35 (q, 2H, CH2CH3), 7.25–6.67 (m, 10H, ArH’s), 8.02 (s, 1H, thiazole H-5). Anal.
calcd. for C28H23N5O4S2 (557.66): C, 60.31; H, 4.16; N, 12.56; S, 11.50. Found: C,
60.32, H; 4.00; N, 12.67; S, 11.42.

NEW THIAZOLES AND PYRAZOLO[1,5-a]PYRIMIDINES
1547
2-[4-(2,3-Dimethyl-5-oxo-1-phenyl(3-pyrazolin-4-yl))(1,3-thiazol-2-yl)]-3-
methylthio-3-(phenylamino)prop-2-enenitrile (17). This compound was
obtained as pale-yellow crystals (DMF); mp 252–254 ꢀC, yield (65%); IR (cmꢁ1):
1
=
=
3320 (NH), 2186 (CN), 1654 (C N), 1593 (C C). H NMR (CD3)2SO d ¼ 2.19 (s,
3H, CH3), 2.54 (s, 3H, CH3), 3.14 (s, 3H, CH3), 7.25–7.49 (m, 11H, ArH’s, NH),
8.04 (s, 1H, thiazole H-5). Anal. calcd. for C24H21N5OS2 (459.60): C, 62.72; H,
4.61; N, 15.24; S, 13.95. Found: C, 60.55, H; 4.52; N, 15.20; S, 13.58.
4-{2-[5-Amino-3-(phenylamino)pyrazolin-4-yl](1,3-thiazol-
2-yl)}-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one (18)
A mixture of 17 (4.6 g, 0.01 mol) and hydrazine hydrate (1 ml, 99%) in ethanol
(20 ml) was heated for 6 h. The resulting solid was collected and recrystallized from
N,N-dimethylformamide to give colorless crystals (AcOH); mp 284–286 ꢀC, yield
1
(75%); IR (cmꢁ1): 3396, 3334, 3139 (NH, NH2), 1653 (CO), 1585 (C C). H NMR
=
(CD3)2SO d ¼ 2.82 (s, 3H, CH3), 3.21 (s, 3H, CH3), 5.81 (s, br., 2H, NH2), 6.76 (t,
1H), 7.20–7.81 (m, 10H, ArH’s), 8.52 (s, 1H, thiazole H-5), 11.24 (s, br., 1H,
NH). Anal. calcd. for C23H21N7OS (443.53): C, 62.29; H, 4.77; N, 22.11; S,7.23.
Found: C, 62.32, H; 4.87; N, 22.18; S, 7.32.
Synthesis of 19, 21a, and 21b
A mixture of 18 (4.43 g, 0.01 mol) and the appropriate 2,4-pentanedione, ethyl
3-oxobutanoate (or acetoacetanilide), or ethyl benzoylacetate (0.01 mol) in acetic
acid (20 ml) was boiled under refluxed for 3 h. The resulting solid was collected
and recrystallized from acetic acid to give 19, 21a, and 21b, respectively.
4-{2-[5,7-Dimethyl-2-(phenylamino)(7a-hydropyrazolo[1,5-a]pyrimidin-
3-yl](1,-thiazol-4-yl)}-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one
(19). This
compound was obtained as buff crystals (AcOH); mp 298–300 ꢀC, yield (69%); IR
1
(cmꢁ1): IR: 3301 (NH), 1639 (C N) and 1602 (C C). H NMR (CD3)2SO d 2.56
(s, 3H, CH3), 2.67 (s, 3H, CH3), 2.87 (s, 3H, CH3), 3.16 (s, 3H, CH3), 6.12 (s, 1H,
pyrimidine H-5), 7.0–7.95 (m, 11H, ArH’s and thiazole H-5) and 9.75 (s, 1H,
NH). Anal. calcd. for C28H25N7OS (507.62): C, 66.25; H, 4.96; N, 19.31; S, 6.32.
Found: C, 66.45, H; 4.85; N, 19.21; S, 6.24.
=
=
3-[4-(2,3-Dimethyl-5-oxo-1-phenyl(3-pyrazolin-4-yl))(1,3-thiazol-2-yl)]-7-
methyl-2-(phenylamino)-4,6,7,7a-tetrahydropyrazolo[1,5-a]-pyrimidin-5-one
(21a). This compound was obtained as buff crystals (AcOH); mp 310–314 ꢀC, yield
1
(72%); IR (cmꢁ1): 3350 (NH), 1687 (CO), 1643 (C N) and 1610 (C C). H NMR
(CD3)2SO d ¼ 2.35 (s, 3H, CH3), 2.57 (s, 3H, CH3), 3.06 (s, 3H, CH3), 8.67 (s, 2H,
2 NH), 5.60 (s, 1H, pyrimidine H-5), 6.87–7.450 (m, 10H, ArH’s), 8.01 (s, thiazole
H-5). Anal. calcd. for C28H25N7OS (507.62): C, 66.25; H, 4.96; N, 19.31; S, 6.32.
Found: C, 66.45, H; 4.85; N, 19.21; S, 6.24.
=
=
3-[4-(2,3-Dimethyl-5-oxo-1-phenyl(3-pyrazolin-4-yl))(1,3-thiazol-2-yl)]-7-
phenyl-2-(phenylamino)-4,6,7,7a-tetrahydropyrazolo[1,5-a]-pyrimidin-5-one
(21b). This compound was obtained as buff crystals (AcOH), mp > 350 ꢀC, yield

1548
A. O. ABDELHAMID AND M. A. M. AFIFI
1
(68%); IR (cmꢁ1): 3432 (NH), 1684 (C O), 1620 (C N), 1600 (C C). H NMR
(CD3)2SO d ¼ 2.96 (s, 3H, CH3), 3.21 (s, 3H, CH3), 6.28 (s, 1H), 7.25–7.60 (m,
15H, ArH’s), 7.92 (s, 1H, thiazole H-5), 9.21 (s, 1H, br., NH), 9.42 (s, 1H, br.,
NH). Anal. calcd. for C32H25N7O2S (571.67): C, 67.23; H, 4.41; N, 17.15; S, 6.61.
Found: C, 67.34, H; 4.34; N, 17.00; S, 5.45.
=
=
=
7-Amino-3-[4-(2,3-dimethyl-5-oxo-1-phenyl(3-pyrazolin-4-yl))(1,3-
thiazol-2yl)]-5-phenyl-2(Phenylamino)-7a-Hydropyrazolo[1,5-a]
pyrimidine-6-carbonitrile (23)
A mixture of 18 (2.2 g, 0.005 mol) and a-cyanocinnaminitrile (0.8 g, 0.005 mol)
in ethanol (20 ml) containing a catalytic amount of piperidine (four to six drops) was
refluxed for 4 h. The resulting solid was collected and recrystallized from N,N-
dimethylformamide to give as yellow crystals (DMF); mp 365–367 ꢀC, yield (65%);
IR (cmꢁ1): 3396, 3334, 3139 (NH, NH2), 1653 (CO), 1585 (C C). 1H NMR
=
(CD3)2SO d ¼ 2.92 (s, 3H, CH3), 3.28 (s, 3H, CH3), 7.25–7.61 (m, 15H, ArH’s),
8.00 (s, 1H, thiazol H-5), 8.95 (s, br., 2H, NH2), 9.75 (s, br., 1H, NH). Anal. calcd.
for C33H25N9OS (571.67): C, 66.54; H, 4.23; N, 21.16; S,5.38. Found: C, 66.45, H;
4.12; N, 21.00; S, 5.45.
4-{2-[5-(1-Aza-2-arylvinyl)-3-(phenylamino)pyrazol-4-yl](1,3-thiazol-
2-yl)}-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one (24a–d)
Sodium ethoxide (0.11 g-atom sodium metal) in ethanol (5 ml) was added
portionwise while stirring to a mixture containing the appropriate benzaldehyde;
4-methylbenzaldehyde, 4-methoxybenzaldehyde, or 4-chlorobenzaldehyde (0.05 mol);
and 18 (2.22 g, mol) for 30 min. The reaction mixture was stirred for 2 h, and then
the resulting solid was collected and recrystallized from acetic acid to give 24a–d,
respectively.
4-{2-[5-(1-Aza-2-phenylvinyl)-3-(phenylamino)pyrazol-4-yl](1,3-thiazol-
2-yl)}-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one (24a). This compound was
obtained as orange crystals (AcOH); mp 255–257 ꢀC, yield (72%); IR (cmꢁ1): 3432
1
=
=
(NH), 1684 (C O), 1600 (C C). H NMR (CD3)2SO d ¼ 2.81 (s, 3H, CH3), 3.22
=
(s, 3H, CH3), 6.92–7.99 (m, 16 H, ArH’s and thiazole H-5), 8.07 (s, 1H, N CH),
8.78 (s, 1H, NH) and 9.16 (s, 1H, NH). Anal. calcd. for C30H25N7OS (531.64): C,
67.78; H, 4.74; N, 18.62; S, 6.03. Found: C, 67.87, H; 4.65; N, 18.62; S, 5.88.
4-{2-[5-(1-Aza-2-(4-methylphenylvinyl)-3-(phenylamino)pyrazol-4-yl](1,3-
thiazol-2-yl)}-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one (24b). This compound
was obtained as yellow crystals (AcOH); mp 226–228 ꢀC, yield (70%); IR (cmꢁ1):
1
=
=
3432 (NH), 1684 (C O), 1600 (C C). H NMR (CD3)2SO d ¼ 2.32 (s, 3H, CH3),
2.81 (s, 3H, CH3), 3.22 (s, 3H, CH3), 6.92–7.99 (m, 15 H, ArH’s and thiazole
=
H-5), 8.07 (s, 1H, N CH), 8.78 (s, 1H, NH), and 9.16 (s, 1H, NH). Anal. calcd.
for C31H27N7OS (545.67): C, 68.34; H, 4.99; N, 17.97; S, 5.88. Found: C, 68.34,
H; 5.12; N, 17.85; S, 6.06.

NEW THIAZOLES AND PYRAZOLO[1,5-a]PYRIMIDINES
1549
4-{2-[5-(1-Aza-2-(4-methoxyphenylvinyl)-3-(phenylamino)pyrazol-4-yl](1,
3-thiazol-2-yl)}-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one (24c). This com-
pound was obtained as yellow crystals (AcOH); mp 245–248 ꢀC, yield (78%); IR
(cmꢁ1): 3432 (NH), 1684 (C O), 1600 (C C). 1H NMR (CD3)2SO d ¼ 2.81 (s,
=
=
3H, CH3), 3.22 (s, 3H, CH3), 3.78 (s, 3H, OCH3), 6.92–7.99 (m, 15 H, ArH’s and
=
thiazole H-5), 8.07 (s, 1H, N CH), 8.78 (s, 1H, NH) and 9.16 (s, 1H, NH). Anal.
calcd. for C31H27N7O2S (561.67): C, 66.29; H, 4.85; N, 17.46; S, 5.71. Found: C,
66.38, H; 4.92; N, 17.64; S, 5.65.
4-{2-[5-(1-Aza-2-(4-chlorophenylvinyl)-3-(phenylamino)pyrazol-4-yl](1,3-
thiazol-2-yl)}-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one (24d). This compound
was obtained as pale-brown crystals (AcOH); mp 235–237 ꢀC, yield (78%); IR
(cmꢁ1): 3432 (NH), 1684 (C O), 1600 (C C). 1H NMR (CD3)2SO d ¼ 2.81 (s,
=
=
3H, CH3), 3.22 (s, 3H, CH3), 6.92–7.99 (m, 15 H, ArH’s and thiazole H-5), 8.07
=
(s, 1H, N CH), 8.78 (s, 1H, NH) and 9.16 (s, 1H, NH). Anal. calcd. for
C30H24ClN7OS (566.09): C, 63.65; H, 4.27; N, 17.32; S, 5.66. Found: C, 63.45, H;
4.32; N, 17.45; S, 5.76.
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