One-pot synthesis of some new semicarbazone, thiosemicarbazone, and hydrazone derivatives of 1-phenyl-3-arylpyrazole-4-carboxaldehyde from acetophenone phenylhydrazones using Vilsmeier-Haack reagent

Article abstract of DOI:10.1080/00397910802372582

Semicarbazone derivatives 3 of 1,3-diphenylpyrazole-4-carboxaldehyde have been synthesized in high yields through a one-pot procedure involving acetophenone phenylhydrazones 1 subjected to Vilsmeier double formylation and workup under new conditions (i.e., treatment with semicarbazide followed by sodium bicarbonate). This method is even suitable for preparing other derivatives (i.e., thiosemicarbazones 4 and hydrazones 5) in high yields. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/00397910802372582

This article was downloaded by: [Stanford University Libraries]
On: 11 July 2012, At: 12:59
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954
Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH,
UK
Synthetic Communications: An
International Journal for Rapid
Communication of Synthetic
Organic Chemistry
Publication details, including instructions for
authors and subscription information:
http://www.tandfonline.com/loi/lsyc20
One-Pot Synthesis of Some
New Semicarbazone,
Thiosemicarbazone, and
Hydrazone Derivatives of
1-Phenyl-3-Arylpyrazole-4-
Carboxaldehyde
from Acetophenone
Phenylhydrazones Using
Vilsmeier–Haack Reagent
Rashmi Pundeer a , Pooja Ranjan a , Kamaljeet
Pannu a & Om Prakash a
a Department of Chemistry, Kurukshetra University,
Kurukshetra, India
Version of record first published: 22 Dec 2008
To cite this article: Rashmi Pundeer, Pooja Ranjan, Kamaljeet Pannu & Om Prakash
(2008): One-Pot Synthesis of Some New Semicarbazone, Thiosemicarbazone,
and Hydrazone Derivatives of 1-Phenyl-3-Arylpyrazole-4-Carboxaldehyde from
Acetophenone Phenylhydrazones Using Vilsmeier–Haack Reagent, Synthetic
Communications: An International Journal for Rapid Communication of Synthetic
Organic Chemistry, 39:2, 316-324

To link to this article: http://dx.doi.org/10.1080/00397910802372582
PLEASE SCROLL DOWN FOR ARTICLE
Full terms and conditions of use: http://www.tandfonline.com/page/terms-
and-conditions
This article may be used for research, teaching, and private study purposes.
Any substantial or systematic reproduction, redistribution, reselling, loan,
sub-licensing, systematic supply, or distribution in any form to anyone is
expressly forbidden.
The publisher does not give any warranty express or implied or make any
representation that the contents will be complete or accurate or up to
date. The accuracy of any instructions, formulae, and drug doses should be
independently verified with primary sources. The publisher shall not be liable
for any loss, actions, claims, proceedings, demand, or costs or damages
whatsoever or howsoever caused arising directly or indirectly in connection
with or arising out of the use of this material.

Synthetic Communications1, 39: 316–324, 2009
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397910802372582
One-Pot Synthesis of Some New Semicarbazone,
Thiosemicarbazone, and Hydrazone Derivatives
of 1-Phenyl-3-Arylpyrazole-4-Carboxaldehyde
from Acetophenone Phenylhydrazones Using
Vilsmeier–Haack Reagent
Rashmi Pundeer, Pooja Ranjan, Kamaljeet Pannu, and Om Prakash
Department of Chemistry, Kurukshetra University, Kurukshetra, India
Abstract: Semicarbazone derivatives 3 of 1,3-diphenylpyrazole-4-carboxaldehyde
have been synthesized in high yields through a one-pot procedure involving aceto-
phenone phenylhydrazones 1 subjected to Vilsmeier double formylation and
workup under new conditions (i.e., treatment with semicarbazide followed by
sodium bicarbonate). This method is even suitable for preparing other derivatives
(i.e., thiosemicarbazones 4 and hydrazones 5) in high yields.
Keywords: Acetophenone, 1,3-diphenylpyrazole-4-carboxaldehyde, phenylhydra-
zones, semicarbazones, thiosemicarbazones, Vilsmeier–Haack reaction
INTRODUCTION
Vilsmeier reaction was initially used for the formylation of activated
aromatic and carbonyl compounds;[1] it is now used as a powerful syn-
thetic tool for the construction of many heterocyclic compounds[2] such
as quinolines, indoles, quinozolines, and pyridine. Synthesis of 4-formyl-
pyrazoles from the double formylation of hydrazones using Vilsmeier–
Haack reagent was first reported by Kira et al. in 1969.[3] The formyl
group present on the pyrazole ring opens up the possibility of carrying
Received May 19, 2008.
Address correspondence to Om Prakash, Department of Chemistry, Kurukshe-
tra University, Kurukshetra 136119, India. E-mail: dromprakash50@rediffmail.com
316

Semicarbazone Derivatives
317
out a diverse range of functional group transformations and is an impor-
tant protocol for the construction of heterocyclic compounds. In the
recent literature, various aryl semicarbazones with established pharma-
cophore requirement have been reported to possess a novel class of anti-
convulsant agent with fewer central nervous system side effects and less
hepatotoxicity.[4] More recently, research on the interaction of DNA
and thiosemicarbazone has received significant attention.[5] In the context
of developing libraries of biologically active pyrazoles,[6] particularly
directed toward the search for new biologically active ligands, we envisi-
oned a versatile access to new aldehyde derivatives (i.e., semicarbazones,
thiosemicarbazones, and hydrazones of 4-formylpyrazoles). Hydrazone
derivatives have been claimed to possess interesting antibacterial,[7] anti-
convulsant,[8] and antituberculosis activities.[9] The possible biological
activities of semicarbazones, thiosemicarbazones, and hydrazones make
it attractive to report a facile, efficient, and one-pot synthesis of some
new derivatives of pyrazole-4-carboxaldehyde from acetophenone
Scheme 1. Method A: One-pot synthesis of some new carbonyl derivatives (3, 4,
and 5) of 4-formylpyrazole under new work-up condition of Vilsmeier–Haack
condition; Method B: Typical procedure for the synthesis of carbonyl derivative
(3) of 4-formylpyrazole.

318
R. Pundeer et al.
phenylhydrazones 1 under Vilsmeier–Haack (VH) conditions (Scheme 1).
Recently it has been shown that the intermediate iminium salt 6 formed in
VH formylation of aromatic substrates can be converted into groups other
than aldehydes such as oximes, using a modified workup procedure that
involves hydroxylamine in one pot.[10] We envisaged that treatment of the
acetophenone phenylhydrazones 1 with VH reagent would lead to iminium
salt of the type 7 followed by semicarbazide to afford desired pyrazole-4-
carboxaldehyde derivatives of the type 3 as shown in method A of Scheme 1.
To test the feasibility of the proposed scheme, acetophenone phenyl-
hydrazone (1a) was subjected to VH conditions using POCl3 and N,N-
dimethylformamide (DMF); the product mixture was worked up under
new conditions using NH2CONHNH2 followed by NaHCO3 to give
the substituted pyrazole (3a) in 78% yield. The chemical structure of
the pure product (recrystallized from ethanol) was confirmed by elemen-
1
tal analysis and spectral data [IR, H NMR, and mass (MS-ES)] data.
The –CH ¼ and –NH signals of newly synthesized compound appeared
as singlets at 8.55 and 9.67 ppm, respectively. The signals of aromatic
protons were also observed at the expected chemical shift. For comparing
the outcome of the present study with that of the reported procedure and
also to characterize the new compounds, the synthesis of 3 was carried
out by a conventional route (method B) which involved the isolation of
aldehyde. The yields obtained by new workup (method A) procedure
are much better than the established route (method B), employing the iso-
lation of aldehyde. Encourgaged by the successful results, we studied the
scope of new method for the synthesis of thiosemicarbazones 4 and
hydrazones 5. The VH reaction of hydrazones 1 using new workup
conditions indeed afforded the new aldehyde derivatives (i.e., thiosemi-
carbazones 4 and hydrazones 5) in good yields (Table 1).
In conclusion, the present study provides an easy access to synthesize
carbonyl derivatives of 4-formylpyrazole under a new workup procedure.
The synthetic route described here is simple, high-yielding, and a one-pot
procedure. Because these compounds contain pyrazole, carbazone, and
hydrazone functions in their structure, they seem to be suitable

Semicarbazone Derivatives
319
Table 1. Physical data of semicarbazone (3), thiosemicarbazone (4), and hydra-
zone (5) derivatives of 4-formylpyrazoles prepared according to Scheme 1
Yieldsa (%)
Compounds
Ar
Mp (ꢀC)
Method A
Method B
3a
3b
3c
3d
3e
3f
C6H5
4-OMeC6H4
4-MeC6H4
4-ClC6H4
4-BrC6H4
4-FC6H4
4-NO2C6H4
C6H5
4-OMeC6H4
C6H5
4-OMeC6H4
110–112
194
193–195
189
192–194
203
195
78
75
79
82
84
86
79
75
78
70
78
52
50
54
45
48
56
40
52
57
57
50
3g
4a
4b
5a
5b
213
174–176
143
150–152
aYields of the isolated products 2 and 3 with regard to 1.
candidates for further chemical modification and may be pharmacolo-
gically active and useful as ligands in coordination chemistry.
EXPERIMENTAL
All reagents were purchased from commercial sources and were used
without further purification. Melting points were taken in open capil-
1
laries in an electrical apparatus and are uncorrected. H NMR spectra
were recorded on a Brucker 300-MHz instrument using TMS as an inter-
nal standard. Infrared (IR) spectra were recorded on a Perkin-Elmer 1800
Fourier transform infrared (FT-IR) spectrophotometer.
General Procedure for the Preparation of Semicarbazone (3),
Thiosemicarbazone (4), and Hydrazone (5) Derivatives of
1,3-Diphenylpyrazole-4-carboxaldehyde
Method A: One-Pot Synthesis of 3 from 1
Acetophenone phenylhydrazone (1a, 0.84 g, 4 mmol) was added to a cold
solution of DMF (10 ml) and phosphorus oxychloride (0.5 ml, 6 mmol),
and the mixture was stirred at 50–60 ꢀC for 5–6 h, cooled to room tem-
perature, and then poured into an ice-cold solution of semicarbazide

320
R. Pundeer et al.
hydrochloride and sodium bicarbonate. The reaction mixture was stirred
overnight. The solid product thus obtained was filtered, washed with
water, and recrystallized from ethanol to give 1,3-diarylpyrazole-4-
caboxyaldehyde semicarbazone (3a) in 78% yield.
Method B: Synthesis of 3 from 1 via Isolation of 2
Step I: Synthesis of 1,3-diphenylpyrazole-4-carboxyaldehyde 2 from 1. To
a cold solution of DMF (10 ml) and phosphorus oxychloride (0.5 ml,
6 mmol), acetophenone phenylhydrazone (1a, 0.84 g, 4 mmol) was added.
The mixture was stirred at 50–60 ꢀC for 5–6 h, cooled to room tempera-
ture, and then poured into ice-cold water. A saturated solution of sodium
bicarbonate was added to neutralize the mixture to give formylpyrazole
2a, isolated by filtration followed by washing with water (0.8 g yield 80%).
Step II: Synthesis of 3 from 2. Semicarbazide hydrochloride (20 mmol)
and sodium acetate (30 mmol) were added to formylpyrazole (2a, 2.4 g,
10 mmol) in 25 ml ethanol, and the reaction mixture was refluxed for
2 h. The reaction mixture was cooled to room temperature and poured
into ice-cold water. The solid thus obtained was filtered, washed with
water, and recrystallized from ethanol to get 3a (2.10 g, yield 69%, overall
yield of step I and step II: 55%).
Characterization Data of 1,3-Diarylpyrazole-4-carboxyaldehyde
Semicarbazones
1,3-Diphenylpyrazole-4-carboxaldehyde Semicarbazone (3a)
IR (KBr): 1682, 1591, 3200, 3345, 3472.2 cmꢁ1 1H NMR (CDCl3,
;
300 MHz): 6.28 (s, 2H, NH2), 7.2–7.7 (m, 10H, Ar–H), 8.2 (s, 1H,
C5H), 8.58 (s, 1H, CH¼N), 9.67 (s, 1H, NH). Anal. calcd. for
C17H15N5O: C, 66.8; H, 4.91; N, 22.95. Found:C, 66.5; H, 4.85; N, 23.12.
1-Phenyl-3-(4-methylphenyl)pyrazole-4-carboxaldehyde Semicarbazone
(3b)
IR (KBr): 1694, 1595, 3207, 3355, 3451 cmꢁ1 1H NMR (CDCl3,
;
300 MHz): 2.5 (s, 1H, CH3), 5.8 (s, 2H, NH2), 7.2–7.8 (m, 9H, Ar–H),
8.2 (s, 1H, C5H), 8.5 (s, 1H, CH¼N), 9.0 (s, 1H, NH). Anal. calcd. for
C18H17N5O: C, 67.7; H, 5.3; N, 21.94. Found:C, 68.02; H, 5.1; N,
21.8.

Semicarbazone Derivatives
321
1-Phenyl-3-(4-methoxyphenyl)pyrazole-4-carboxaldehyde
Semicarbazone (3c)
IR (KBr): 1698, 1603, 3188, 3357, 3458.3 cmꢁ1 1H NMR (CDCl3,
;
300 MHz): 3.6 (s, 3H, OCH3), 6.08 (s, 2H, NH2), 7.4–7.8 (m, 9H, Ar–
H), 8.314 (s, 1H, C5H), 8.59 (s, 1H, CH¼N), 9.59 (s, 1H, NH). Anal.
calcd. for C18H17N5O2: C, 64. 4; H, 5.0; N, 20.89. Found:C, 64.32; H,
4.89; N, 20.73.
1-Phenyl-3-(4-bromophenyl)pyrazole-4-carboxaldehyde
Semicarbazone (3d)
IR (KBr): 1700, 1595, 3189, 3357, 3484.3 cmꢁ1 1H NMR (CDCl3,
;
300 MHz): 6.0 (s, 2H, NH2), 7.2–7.8 (m, 9H, Ar–H), 8.314 (s, 1H, C5H),
8.71 (s, 1H, CH¼N), 9.69 (s, 1H, NH). Anal. calcd. for C17H14N5OBr:
C, 53.12; H, 3.64; N, 18.22. Found:C, 53.13; H, 3.6; N, 18.17.
1-Phenyl-3-(4-chlorophenyl)pyrazole-4-carboxaldehyde
semicarbazone (3e)
IR (KBr): 1702, 1596, 3195, 3375, 3471.3 cmꢁ1 1H NMR (CDCl3,
;
300 MHz): 6.16 (s, 2H, NH2), 7.2–7.7 (m, 9H, Ar–H), 8.2 (s, 1H, C5H),
8.58 (s, 1H, CH¼N), 9.89 (s, 1H, NH). Anal. calcd. for C17H14N5OCl:
C, 60.17; H, 4.12; N, 20.6. Found:C, 60.11; H, 4.36; N, 20.2. Mass:
Mþ341.
1-Phenyl-3-(4-fluorophenyl)pyrazole-4-carboxaldehyde
Semicarbazone (3f)
IR (KBr): 1708, 1593, 3200, 3331, 3470 cmꢁ1 1H NMR (DMSO,
;
300 MHz): 6.28 (s, 2H, NH2), 7.3–8.3 (m, 10H, Ar–H), 8.8 (s, 1H,
CH¼N), 10.13 (s, 1H, NH). Anal. calcd. for C17H14N5OF: C, 63.15;
H, 4.33; N, 21.6. Found:C, 63.11; H, 4.54; N, 21.57.
1-Phenyl-3-(4-nitrophenyl)pyrazole-4-carboxaldehyde
Semicarbazone (3g)
IR (KBr): 1708, 1595, 3220, 3330, 3470 cmꢁ1 1H NMR (DMSO,
;
300 MHz): 6.28 (s, 2H, NH2), 7.5–8.5 (m, 10H, Ar–H), 8.78 (s, 1H,
CH¼N), 10.03 (s, 1H, NH). Anal. calcd. for C17H14N6O3: C, 58.28; H,
4.00; N, 24.0. Found:C, 58.28; H, 4.35; N, 24.2.

322
R. Pundeer et al.
1,3-Diphenylpyrazole-4-carboxaldehyde Thiosemicarbazone (4a)
IR (KBr): 1620, 3159, 3333, 3400 cmꢁ1; 1H NMR (CDCl3, 300 MHz): 5.0
(s, 2H, NH2), 6.7–7.2 (m, 10H, Ar–H), 8.0 (s, 1H, C5H), 8.3 (s, 1H,
CH¼N), 8.9 (s, 1H, NH). Anal. calcd. for C17H15N5S: C, 63.35; H,
4.6; N, 21.80. Found:C, 63.30; H, 4.96; N, 21.8. Mass: Mþ321.
1-Phenyl-3-(4-methoxyphenyl)pyrazole-4-carboxaldehyde
Thiosemicarbazone (4b)
IR (KBr): 1614, 3200, 3315, 3400 cmꢁ1; 1H NMR (CDCl3, 300 MHz): 3.8
(s, 3H, OMe), 5.28 (s, 2H, NH2), 6.8–7.4 (m, 10H, Ar–H), 8.3 (s, 1H,
C5H), 8.5 (s, 1H, CH¼N), 9.8 (s, 1H, NH). Anal. Calcd. for
C18H17N5OS: C, 61.5; H, 4.84; N, 19.9. Found:C, 61.57; H, 4.9; N, 20.1.
1,3-Diphenylpyrazole-4-carboxaldehyde Hydrazone (5a)
1
IR (KBr): 1603, 3321 cmꢁ1; H NMR (CDCl3, 300 MHz): 7.2–7.7 (m,
11H, Ar–H). Anal. calcd. for C23H20N4O: C, 78.10; H, 5.32; N, 16.5.
Found:C, 78.26; H, 5.44; N, 16.24.
1-Phenyl-3-(4-methoxyphenyl)pyrazole-4-carboxaldehyde
Hydrazone (5b)
1
IR (KBr): 1600, 3321 cmꢁ1; H NMR (CDCl3, 300 MHz): 3.8 (s, 3H,
OMe), 7.2–7.7 (m, 10H, Ar–H). Anal. calcd. for C23H20N4O: C, 75.0;
H, 5.43; N, 15.2. Found:C, 75.17; H, 5.44; N, 15.24.
ACKNOWLEDGMENTS
We are thankful to Council of Scientific and Industrial Research, New
Delhi, for the award of a junior research fellowship to Pooja Ranjan
and Defense Research Development Organization (ERIP=ER=0103294=
M=01), New Delhi, for the award of a senior research fellowship to
Kamaljeet Pannu to carry out this work.
REFERENCES
1. Marson, C. M. Reactions of carbonyl compounds with (monohalo) methyl-
eniminium salts (vilsmeier reagents). Tetrahedron 1992, 48, 3659.
2. (a) Meth-Cohn, O. The synthesis of pyridines, quinolines, and other related
systems by the Vilsmeier and the reverse Vilsmeier method. Heterocycles

Semicarbazone Derivatives
323
1993, 35, 539; (b) Guzman, A.; Ronero, M.; Maddox, M. L.; Machowski, J.
M. Vilsmeier–Haack reaction with glutarimides: Synthesis of 2,6-dichloro-
1,4-dihydropyridine-3,5-dicarboxaldehydes. J. Org. chem. 1990, 55, 5793; (c)
Mahatta, P. K.; Venktash, C.; Shyam kumar, U. K.; Ila, H.; Junjappa, H.
Reaction of -oxoketene-n,s-arylaminoacetals with Vilsmeier reagents: An effi-
cient route to highly functionalized quinolines and their benzo=hetero-fused
analogues. J. Org. Chem. 2003, 68, 3966; (d) Katrizky, A. R.; Arend, M. A.
Convenient and highly regioselective one-pot synthesis of quinolines by addi-
tion of a Vilsmeier-type reagent to n-arylimines. J. Org. Chem. 1998, 63, 9989.
3. Kira, M. A.; Abdel-Rahman, M. O.; Gadalla, K. Z. The Vilsmeier–Haack
reaction III: Cyclization of hydrazones to pyrazoles. Tetrahedron Lett.
1969, 10, 109.
4. (a) Dimmock, J. R.; Puthucode, R. N.; Smith, J. M.; Hetherington, M.;
Quail, J.W.; Pugazhenthi, U.; Lechler, T.; Stables, J. P. (Aryloxy)aryl semi-
carbazones and related compounds: A novel class of anticonvulsant agents
possessing high activity in the maximal electroshock screen. J. Med. Chem.
1996, 39, 3984; (b) Dimmock, J. R.; Vashishtha, S. C.; Stables, J. P. Anti-
convulsant properties of various acetylhydrazones, oxamoylhydrazones,
and semicarbazones derived from aromatic and unsaturated carbonyl com-
pounds. Eur J. Med. Chem. 2000, 35, 241; (c) Yogeeswari, P.; Sriram, D.;
Thirumurugan, R.; Reghavendran, J. V.; Sudhan, K.; Kumar, R. P.; Stables,
J. Discovery of N-(2,6-dimethylphenyl)-substituted semicarbazones as antic-
onvulsants: Hybrid pharmacophore-based design. J. Med. Chem. 2005, 48,
6202; (d) Yogeeswari, P.; Sriram, D.; Saxena, A.; Thirumurugan, R.; Stables,
J. 2,4-Dimethoxyphenylsemicarbazones with anticonvulsant activity against
three animal models of seizures: Synthesis and pharmacological evaluation.
Biorg. Med. Chem. 2006, 14, 3106; (e) Yogeeswari, P.; Thirumurugan, R.;
Sriram, D.; Suniljit, L. R. J.; Reghavendran, J. V.; Kavya, R.; Rakhera,
K.; Stables, J. Synthesis of N4-(2,4-dimethylphenyl) semicarbazones as
4-aminobutyrate aminotransferase inhibitors. Acta Pharm. 2006, 56, 259.
(f) Berlado, H.; Gambino, D. The wide pharmacological versatility of semi-
carbazones, thiosemicarbazones, and their metal complexes. Mini-Rev.
Med. Chem. 2004, 4(1), 31.
5. Bal, T.; Atasever, B.; Solakoglu, Z.; Kuruca, S. E.; Wkiiseven, B. Synthesis,
characterization, and cytotoxic properties of the N1,N4-diarylidene-S-methyl-
thiosemicarbazone chelates with Fe(III) and Ni(II). Eur. J. Med. Chem. 2007,
42, 161.
6. (a) Prakash, O.; Kumar, R.; Bhardwaz, V.; Sharma, P. K. Synthesis of some
new 3-aryl-4-formyl-1-(4,6-dimethyl-2-pyrimidinyl)pyrazoles using Vilsmeier–
Haack reaction. Hetcrocycl. Commun. 2003, 9(5), 515; (b) Kumar, A.;
Prakash, O.; Kinger, M.; Singh, S. P. Synthesis of some new 1-aryl-4-
formyl-3-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)pyrazoles using the
Vilsmeier–Haack reaction—Isolation of the key intermediate 1-aryl-3-(4-
hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)pyrazoles.Can.J.Chem.2006,84,438.
7. (a) Loncle, C.; Brunel, J. M.; Vidal, N.; Dherbomez, M.; Letourneux, Y.
Synthesis and antifungal activity of cholesterol-hydrazone derivatives. Eur.

324
R. Pundeer et al.
J. Med. Chem. 2004, 39, 1067 (b) Vicini, P.; Zani, F.; Cozzini, P:
Doytchinova, I. Hydrazones of 1,2-benzisothiazole hydrazides: Synthesis,
antimicrobial activity, and QSAR investigations. Eur. J. Med. Chem. 2002,
37, 553.
8. (a) Popp, F. D. Potential anticonvulsant, XII: Anticonvulsant activity of
some aldehyde derivatives. Eur. J. Med. Chem. 1989, 24, 313 (b) Sridhar,
S. K.; Pandeya, S. N.; Stables, J. P.; Atmakuru, R. The influence of particles
of a minor component on the matrix strength of sodium chloride. Eur. J.
Pharma. Sci. 2002, 16, 129 (c) Kuchukguzel, S. G.; Mazi, A.; Sahin, F.;
Ozturk, S.; Stables, J. P. Synthesis and biological activities of diflunisal
hydrazide–hydrazones. Eur. J. Med. Chem. 2003, 38, 1005.
9. (a) Kuchukguzel, S. G.; Rollas, S.; Kuchukguzel, I.; Kiraz, M. Synthesis and
antimycobacterial activity of some coupling products from 4-aminobenzoic
acid hydrazones. Eur. J. Med. Chem. 1999, 34, 1093 (b) Patole, J.;
Sandbhor, U.; Padhye, S.; Deobagkar, D. N.; Arison, C. E.; Powell, A. Struc-
tural chemistry and in vitro antitubercular activity of acetylpyridine benzoyl
hydrazone and its copper complex against Mycobacterium smegmatis. Biorg.
Med. Chem. Lett. 2003, 13, 51 (c) Rando, D. G.; Sato, D. N.; Siqueira, L.;
Malvezzi, A.; Leite, C. Q. F.; Amaral, A. T.; Ferreira, E. J.; Tavares, L. C.
Synthesis, DNA binding, topoisomerases inhibition and cytotoxic properties
of 4-arylcarboxamidopyrrolo-2-carboxyanilides. Biorg. Med. Chem. Lett.
2002, 10, 557.
10. Prakash, O.; Pannu, K.; Kaur, H.; Naithani, R. One-pot synthesis of oxime
derivatives of 1,3-diphenylpyrazole-4-carboxaldehydes from acetophenone
phenylhydrazones using Vilsmeier–Haack reagent. Synth. Commun. 2006,
36, 3479.