Design and synthesis of 4-(1-(4-chlorobenzyl)-2,3-dioxoindolin-5-yl)-1-(4- substituted/unsubstituted benzylidene) semicarbazide: Novel agents with analgesic, anti-inflammatory and ulcerogenic properties

Article abstract of DOI:10.1016/j.cclet.2012.03.014

A new series of isatin semicarbazide derivatives (7a-7j) were synthesized and characterized by spectroscopic means and elemental analysis. Analgesic and anti-inflammatory screening was performed using tail-flick technique and the carrageenan-induced foot

Full text of DOI:10.1016/j.cclet.2012.03.014

Available online at www.sciencedirect.com
Chinese Chemical Letters 23 (2012) 541–544
www.elsevier.com/locate/cclet
Design and synthesis of 4-(1-(4-chlorobenzyl)-2,
3-dioxoindolin-5-yl)-1-(4-substituted/unsubstituted
benzylidene) semicarbazide: Novel agents with analgesic,
anti-inflammatory and ulcerogenic properties
b
c
Chinnasamy Rajaram Prakash a, , Sundararajan Raja , Govindaraj Saravanan
*
a Department of Medicinal Chemistry, DCRM Pharmacy College, JNTUH, Andhra Pradesh, India
b Department of Pharmaceutical Chemistry, GITAM Institute of Pharmacy, GITAM University, Vizag, Andhra Pradesh, India
c Medicinal Chemistry Research Laboratory, Bapatla College of Pharmacy, Bapatla 522 101, Andhra Pradesh, India
Received 23 November 2011
Available online 19 April 2012
Abstract
A new series of isatin semicarbazide derivatives (7a–7j) were synthesized and characterized by spectroscopic means and
elemental analysis. Analgesic and anti-inflammatory screening was performed using tail-flick technique and the carrageenan-
induced foot paw edema test respectively. The ulcerogenicity was also determined for all the compounds. Some of the compounds
showed moderate enhancement of the activity. Among the synthesized derivatives, compound 7d showed higher analgesic,
antiinflammatory and one-third of ulcer index of the reference drug.
# 2012 Chinnasamy Rajaram Prakash. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
Keywords: Isatin; Anti-nociceptive; Schiff base; Ulcerogenicity
Non-steroidal anti-inflammatory drugs (NSAIDs) are one of the frequently useful clinical therapies for the
treatment of minor pain and for the management of edema and tissue damage resulting from inflammatory joint
disease (arthritis) [1]. The major mechanism by which the NSAIDs elicit their therapeutic effects is inhibition of
cyclooxygenase, the enzymes that catalyze the synthesis of cyclic endoperoxides from arachidonic acid to form
prostaglandins. Generally, the NSAIDs inhibit both isoforms COX-1 and COX-2. However, long term clinical usages
of NSAIDs are associated with significant side effects such as severe gastrointestinal lesions, renal and hepatic [2,3]
toxicities. Thus, developing new therapeutic agents that can overcome gastrointestinal injury and at the same time
could lead to an enhanced anti-inflammatory effect becomes an urgent need for inflammation patients.
Isatin is a core structure in various synthetic pharmaceuticals displaying a wide variety of biological activities [4–
6]. These exciting properties encouraged many efforts toward the synthesis and pharmacological screening of many
isatin derivatives. On the other hand, semicarbazide derivatives show promising biological and pharmacological
activities [7]. In recent years, aryl and heteroaryl semicarbazides have documented increasing advances in analgesic
* Corresponding author.
E-mail address: crp2020@gmail.com (C.R. Prakash).
1001-8417/$ – see front matter # 2012 Chinnasamy Rajaram Prakash. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
doi:10.1016/j.cclet.2012.03.014

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C.R. Prakash et al. / Chinese Chemical Letters 23 (2012) 541–544
Scheme 1. Reagents and conditions: (a) H2SO4, HNO3; (b) K2CO3, DMF, p-chloro benzyl chloride; (c) reduction, Fe/HCl; (d) C2H5OH, GlaÁ
CH3COOH, NaOCN; (e) reflux, NH2NH2.H2O, C2H5OH; (f) R-CHO, C2H5OH, GlaÁ CH3COOH.
and anti-inflammatory drug design [8,9]. With the aforementioned findings, in this work, we present the synthesis of
several isatin semicarbazide derivatives.
1. Experimental
The chemicals were obtained from units Merck India Ltd. All the reaction steps were monitored by TLC. Melting
points were taken in open glass capillary and are uncorrected. 1H NMR spectra were taken on a Bruker ultra shield
(300 MHz) NMR spectrometer. Mass spectra were obtained on a JEOL-SX-102 instrument. IR spectra were recorded
in KBr pellets on a Jasco FT-IR 410 spectrometer. Elemental analyses were performed on a Perkine Elmer model 240C
analyzer.
The synthetic pathway giving access to the final compounds (7a–7j) is illustrated in Scheme 1. The synthetic route
was initiated with the preparation of 5-nitro isatin 2, which involved a nitration of isatin 1 by nitric acid and sulfuric
acid. In the next step, compound 3 was synthesized by treating 5-nitro isatin (2) in DMF which was added to excess
K2CO3 followed by addition of 4-chloro benzyl chloride and the reaction was left to mix at 70 8C for 6 h. Compound 3
was recrystallized from ethanol. The nitro group presented in compound 3 gets reduced to amino group by heating
with a mixture of hydrochloric acid and iron powder to offer 4. On stirring with sodium cyanate and glacial acetic acid,
compound 4 got reduced to its respective urea derivative 5. Further these urea derivatives were treated with hydrazine
hydrate in ethanol to furnish semicarbazide 6. Finally, the compounds 7a–7j was synthesized by a Schiff base reaction,
in which a different aromatic/heterocyclic aldehydes (carbonyl compound) and amino derivative (6) underwent
nucleophilic addition in ethanol with few drops of glacial acetic acid, forming a hemiaminal. This reaction was
followed by a dehydration to generate the title compounds 7a–7j by forming a stable imine.
2. Results and discussion
The 1H NMR spectrum of 7d, showed signals at d 4.64 (s, 2H, CH2); 7.02–7.88 (m, 11H, Ar-H); 8.32 (s, 1H, Ar-
NH); 8.64 (s, 1H, CH N); 9.96 (s, 1H, CONH). Also, its IR spectrum displayed absorption bands at 1544 cmÀ1
(CH N), which confirms the formation of product through azomethine linkage by Schiff base reaction. The other
stretching vibrations at 1112 and 1728 cmÀ1 also confirms the formation of 7d, which was assigned to C–F and C O
respectively. The physicochemical parameters of all the synthesized compounds are summarized in Table 1.
Test for analgesic activity was carried out by tail-flick technique using Wistar albino mice [10]. All the results
obtained are summarized in Table 1. The results of analgesic activity showed that test compounds exhibited moderate
analgesic activity at 30 min of reaction time; the activity increased at 1 h, further it reached to peak level at 2 h and past
its best in activity was observed at 3 h. Compounds with chloro or nitro substituent 7b and 7e showed good activity.
With the increased lipophilicity (fluoro and trifluoro methyl substituents, compounds 7c and 7d) showed increased in
activity. Heterocyclic ring substituted compounds (indole (7i), 5-methyl furan (7j)) retains the activity as like as
standard drug. Electrondonating groups like methyl 7f, methoxy 7g and hydroxy 7h substituted derivatives leads to
moderate decrease in activity. The unsubstituted phenyl derivative 7a turns to further decreases in activity. Compounds

Table 1
Physicochemical, analgesic, anti-inflammatory activities and ulcer index of synthesized compounds (7a–7j).
Compd.
Formula
Mp
Log Pa Dose
(mg/kg)
Percentage analgesic activityb
Percentage protection in paw edemab
Ulcer index
30 min
1 h
2 h
3 h
30 min
1 h
2 h
3 h
7a
7b
7c
7d
7e
7f
C23H17ClN4O3
242–244 3.87
10
27 Æ 1.39*
34 Æ 1.21*
34 Æ 1.21*
43 Æ 1.92*
40 Æ 1.46*
47 Æ 1.32*
49 Æ 1.05*
30 Æ 1.32*
36 Æ 1.74*
40 Æ 1.18*
50 Æ 1.63*
46 Æ 1.42*
60 Æ 1.51*
55 Æ 1.09*
35 Æ 1.32*
39 Æ 1.31*
42 Æ 1.31*
26 Æ 1.06* 26 Æ 1.16*
33 Æ 1.32* 30 Æ 1.71*
37 Æ 1.49* 33 Æ 1.07*
30 Æ 1.83*
32 Æ 1.21*
38 Æ 1.12*
32 Æ 1.62*
33 Æ 0.93*
39 Æ 1.23*
26 Æ 1.23* 1.12 Æ 0.27
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
10
20
30 Æ 1.80*
C23H16Cl2N4O3 265–267 4.43
C23H16ClFN4O3 258–260 4.03
C24H16ClF3N4O3 262–264 4.79
33 Æ 1.22* 0.57 Æ 0.42
55 Æ 1.370* 46 Æ 1.32* 48 Æ 1.47** 52 Æ 1.56** 60 Æ 1.72** 41 Æ 1.76*
48 Æ 1.39*
65 Æ 1.31*
59 Æ 1.67*
47 Æ 1.72* 31 Æ 1.27*
60 Æ 1.39* 43 Æ 134*
48 Æ 1.16* 41 Æ 1.21*
37 Æ 1.42*
50 Æ 1.30*
42 Æ 1.26*
38 Æ 1.37*
31 Æ 1.63* 0.52 Æ 0.32
59 Æ 1.41** 47 Æ 1.96*
46 Æ 1.63*
38 Æ 1.36* 0.48 Æ 0.38
52 Æ 1.22*** 60 Æ 1.51*** 69 Æ 1.03*** 62 Æ 1.15* 48 Æ 1.32*** 55 Æ 1.62*** 64 Æ 2.03*** 42 Æ 1.23*
C23H16ClN5O5
C24H19ClN4O3
C24H19ClN4O4
C23H17ClN4O4
C25H18ClN5O3
C22H17ClN4O4
274–276 2.36
212–214 4.36
222–224 3.74
238–240 3.48
252–254 3.41
286–288 2.82
32 Æ 1.72*
42 Æ 1.11*
30 Æ 1.69*
32 Æ 1.49*
27 Æ 1.43*
30 Æ 1.61*
26 Æ 1.06*
34 Æ 1.15*
37 Æ 1.09*
38 Æ 1.57*
45 Æ 1.69*
36 Æ 1.96*
38 Æ 1.72*
31 Æ 1.63*
36 Æ 1.74*
33 Æ 1.12*
38 Æ 1.69*
44 Æ 1.90*
39 Æ 1.82*
48 Æ 1.71*
38 Æ 1.90*
41 Æ 1.31*
35 Æ 1.32*
43 Æ 1.47*
40 Æ 1.18*
42 Æ 1.31*
45 Æ 1.56*
33 Æ 1.32* 29 Æ 1.18*
39 Æ 1.82* 41 Æ 1.38*
29 Æ 1.82* 27 Æ 1.41*
35 Æ 1.16* 36 Æ 1.07*
26 Æ 1.37* 28 Æ 1.71*
39 Æ 1.93* 32 Æ 1.73*
34 Æ 1.15* 26 Æ 1.61*
37 Æ 1.23* 29 Æ 1.26*
38 Æ 1.37* 27 Æ 1.29*
36 Æ 1.31*
46 Æ 2.32*
30 Æ 1.42*
39 Æ 1.39*
31 Æ 1.29*
34 Æ 1.74*
31 Æ 1.43*
33 Æ 1.53*
32 Æ 1.17*
38 Æ 1.72*
31 Æ 1.72*
33 Æ 1.24*
6.1 Æ 0.27
38 Æ 1.58*
37 Æ 1.39*
58 Æ 1.37*
33 Æ 1.29*
43 Æ 1.32*
33 Æ 1.24*
40 Æ 1.23*
32 Æ 1.21*
41 Æ 1.39*
35 Æ 1.22*
40 Æ 1.17*
35 Æ 1.60*
39 Æ 1.57*
5.7 Æ 0.32
39 Æ 1.97*
34 Æ 1.33* 0.59 Æ 0.33
42 Æ 1.92*
26 Æ 1.16* 0.86 Æ 0.33
31 Æ 1.43*
7g
7h
7i
29 Æ 1.26* 0.92 Æ 0.62
31 Æ 1.63*
27 Æ 1.23* 0.89 Æ 0.17
30 Æ 1.32*
32 Æ 1.71* 0.68 Æ 0.41
37 Æ 1.87*
46 Æ 1.15** 56 Æ 1.26*** 61 Æ 1.51** 52 Æ 1.58* 36 Æ 1.72*
7j
36 Æ 1.81*
45 Æ 1.62*
46 Æ 1.42*
39 Æ 1.72* 29 Æ 1.30*
30 Æ 1.30* 0.65 Æ 0.52
33 Æ 1.24*
45 Æ 1.46** 55 Æ 1.62*** 60 Æ 1.51** 50 Æ 1.52* 31 Æ 1.47*
Control
–
–
–
–
–
–
–
–
–
–
–
–
2 Æ 0.35
37 Æ 1.69*
46 Æ 0.95*
–
6 Æ 0.49
4 Æ 0.59
4 Æ 0.91 5.1 Æ 0.29
33 Æ 0.96* 32 Æ 0.63*
3.2 Æ 0.93
33 Æ 0.93*
0.15 Æ 0.32
Diclofenac
10
20
43 Æ 1.42*
45 Æ 0.94*
55 Æ 1.16** 62 Æ 1.49*** 39 Æ 1.13* 45 Æ 1.63*
52 Æ 0.92*** 60 Æ 1.52*** 42 Æ 1.36** 1.65 Æ 0.59
Aspirin
200
–
–
–
–
–
–
–
1.73 Æ 0.41
a
Log P was calculated with Chem office 2009 software.
Each value represents the mean Æ SEM (n = 6).
b
*
p < 0.5 significance levels as compared with the respective control.
p < 0.01 significance levels as compared with the respective control.
p < 0.001 significance levels as compared with the respective control.
**
***

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C.R. Prakash et al. / Chinese Chemical Letters 23 (2012) 541–544
7c and 7d emerged as the most active analgesic agent and it is moderately more potent when compared to the reference
standard diclofenac sodium.
Anti-inflammatory activity was performed by carrageenan-induced paw edema test in rats [11]. The anti-
inflammatory activity results (Table 1) showed that compounds showed maximum activity at 2 h. The compounds with
electron withdrawing group like chloro, fluoro and nitro (compounds 7b, 7c and 7e) exhibited equipotent activity when
compared to the standard diclofenac. With increased lipophilicity the compound with trifluoro methyl substituent 7d
showed more potent activity compared to standard. Replacement of this electron withdrawing groups by electron
donating substituents like methyl, methoxy and hydroxy (compounds 7f, 7g and 7h) leads to moderate decrease in
activity. Unlike analgesic activity, the replacement of distal phenyl ring by heterocyclic nucleus like indole 7i and 5-
methyl furan 7j leads to further decrease in activity. Among all the synthesized compounds the unsubstituted distal
phenyl ring derivative 7a exhibited least activity.
The ulcer index of the synthesized compounds (Table 1) reveals that the compounds 7b–7e possessing electron
withdrawing substituents showed negligible ulcer index, whereas compounds 7i and 7j exhibited little increases in
ulcer index. Compounds bearing electron donating groups 7f, 7g and 7h exhibited higher ulcer index over other test
compounds. When compared to diclofenac and aspirin test compounds exhibited 28–66% of the ulcer index.
Compounds 7d and 7c exhibited least ulcer index which is about one-third of the ulcer index of reference drugs.
Compound 7a showed highest ulcer index of about 66% when compared to standard drugs.
In summary, a new series of isatin derivatives has been prepared and fully assigned by analytical and spectral data.
The results of the analgesic and anti-inflammatory activities of the synthesized compounds showed that moderate
enhancement of the activity. Compound 7d exhibited 59% and 69% analgesic activity at 10 and 20 mg/kg dose level,
respectively, at the reaction time of 2 h. The compound 7d also showed 46% and 64% anti-inflammatory activity at the
dose 10 and 20 mg/kg, respectively, at the reaction time of 2 h. Interestingly this compound showed one-third of ulcer
index of the reference diclofenac and aspirin. Hence this analog could be developed as a new class of analgesic and
anti-inflammatory agents. However, further structural modification is planned to enhance the analgesic and anti-
inflammatory activities with the decreased ulcerogenic index.
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