Synthesis and biological activities of some new fluorinated coumarins and 1-aza coumarins

Article abstract of DOI:10.1016/j.ejmech.2007.08.007

A series of new fluorinated coumarins and 1-aza coumarins have been synthesized and the presence of fluorine in these molecules and its effect on their anti-microbial, anti-inflammatory and analgesic activities are discussed. The results of bioassay showed that these newly synthesized compounds containing fluorine exhibit moderate analgesic and excellent anti-inflammatory and potential anti-bacterial and anti-fungal activities, compared to the other halogenated compounds. All the newly synthesized compounds were characterized by elemental analysis, IR, ¹H NMR, ¹³C NMR, ¹⁹F NMR, EI-MS, and FAB-MS. The ORTEP diagram of one of the compounds is reported herein.

Full text of DOI:10.1016/j.ejmech.2007.08.007

Available online at www.sciencedirect.com
European Journal of Medicinal Chemistry 43 (2008) 2178e2188
http://www.elsevier.com/locate/ejmech
Original article
Synthesis and biological activities of some new fluorinated
coumarins and 1-aza coumarins
a
Rajesh G. Kalkhambkar a, Geeta M. Kulkarni a, , Chandrappa M. Kamanavalli ,
*
N. Premkumar b, S.M.B. Asdaq b, Chung Ming Sun c
a Department of Chemistry, Karnatak University’s Karnatak Science College, College Road, Dharwad 580001, Karnataka, India
b Department of Pharmacology, Krupanidhi College of Pharmacy, Bangalore 560034, Karnataka, India
c Department of Applied Chemistry, National Chiao-Tung University, Hsinchu 300-50, Taiwan
Received 5 May 2007; received in revised form 16 July 2007; accepted 9 August 2007
Available online 11 September 2007
Abstract
A series of new fluorinated coumarins and 1-aza coumarins have been synthesized and the presence of fluorine in these molecules and its
effect on their anti-microbial, anti-inflammatory and analgesic activities are discussed. The results of bioassay showed that these newly synthe-
sized compounds containing fluorine exhibit moderate analgesic and excellent anti-inflammatory and potential anti-bacterial and anti-fungal ac-
tivities, compared to the other halogenated compounds. All the newly synthesized compounds were characterized by elemental analysis, IR, 1H
NMR, 13C NMR, 19F NMR, EI-MS, and FAB-MS. The ORTEP diagram of one of the compounds is reported herein.
Ó 2007 Elsevier Masson SAS. All rights reserved.
Keywords: Fluorinated coumarin; Fluorinated 1-aza coumarin; Anti-bacterial; Anti-fungal; Analgesic; Anti-inflammatory
1. Introduction
to inhibit these enzymes in inhibiting inflammation [3e5].
The potential of coumarin derivatives as anti-inflammatory
agents has been explored in our laboratory, by incorporating
biocompatible pharmacophores like vanillyl, cyanoester and
paracetamol, at the allylic position with respect to C3eC4
double bond of the coumarin moiety [6,7].
1-Aza coumarin derivatives, which ultimately metabolize
as the corresponding 8-hydroxy coumarins in the biological
system are therefore found to be very good anti-inflammatory
and analgesic agents [8]. The triheterocyclic thiazoles synthe-
sized from 4-aminomethyl carbostyrils and 3-bromoacetyl
coumarins [9] in our laboratory were found to exhibit promis-
ing anti-inflammatory and analgesic activities even after 24 h.
Interest in coumarins and 1-aza coumarins as antibiotics is
due to the recent observations that these are potent inhibitors
of bacterial DNA gyrase, which is involved in cell growth
[10,11]. Many coumarin and 1-aza coumarin derivatives,
with variety of substituents at 4-position, with very good
anti-bacterial activity have been reported from our laboratory
[12e15].
Coumarin and its nitrogen analogue 1-aza coumarin (also
known as carbostyril) are a class of lactones and lactams, re-
spectively, which are indispensable heterocyclic units to both
the chemists and the biochemists. A comparative review of
these two systems has been reported recently, for their natural
occurrence, anti-microbial, anti-inflammatory, anti-cancer and
other miscellaneous properties [1]. Many coumarin derivatives
are known for their special property of scavenging Reactive
Oxygen Species (ROS) and have been found to be inhibitors
of cyclooxygenase and lipoxygenase in the arachidonic acid
pathway of inflammation suppression [2]. Non steroidal anti-
inflammatory drugs (NSAIDs) have a broad spectrum of ef-
fects in acute pain management and target the cyclooxygenase
enzyme. Several coumarin derivatives have been reported for
their significant anti-inflammatory activities and their ability
* Corresponding author. Tel.: þ91 836 2770476; fax: þ91 836 2747884.
E-mail address: geeta_2562005@yahoo.com (G.M. Kulkarni).
0223-5234/$ - see front matter Ó 2007 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2007.08.007

R.G. Kalkhambkar et al. / European Journal of Medicinal Chemistry 43 (2008) 2178e2188
2179
Incorporation of fluorine into organic molecules can lead to
distinctive modification in their biological properties [16].
Fluorinated heterocycles have been found to exhibit enhanced
enzyme inhibiting [17] and anti-microbial activities, as com-
pared to their non-fluorinated analogues [18,19]. A series of
3-amino carbostyril derivatives containing fluorine have been
reported as promising potassium (Maxi-K) channel openers,
targeted for neuroprotection [20].
substituted 4-[(40-fluoro) anilinomethyl]-coumarins (5aee)
were synthesized by refluxing the reaction mixture of 4-fluo-
roaniline and various 4-bromomethyl coumarins in dry xylene
at 135e148 ꢀC. Similarly by a different sequence of reactions,
4-bromomethyl carbostyrils (8aed) were synthesized by the
bromination of acetoacetanilides and cyclising the intermediate
u-bromo acetoacetanilides in sulphuric acid [22] (Scheme 2).
The substituted 4-[(40-fluoro) phenoxymethyl]-carbostyrils
(9aed) were synthesized by refluxing the reaction mixture
of 4-fluorophenol and anhydrous K2CO3 with various 4-bro-
momethyl carbostyrils in absolute alcohol at 100 ꢀC. In an
analogous manner the substituted 4-[(40-fluoro)-anilino-
methyl]-carbostyrils (10aed) were synthesized by refluxing
the reaction mixture of 4-fluoroaniline and various 4-bromo-
methyl carbostyrils in dry xylene at 135e148 ꢀC.
Hence the purpose of the present work was to explore and
develop the new templates containing fluorine, coumarin and
1-aza coumarin, with three points of molecular diversity.
2. Chemistry
Synthesis of various 4-bromomethyl coumarins [21] was
brought about by the Pechman cyclisation of phenols with 4-
bromoethylacetoacetate (Scheme 1). The substituted 4-[(40-
fluoro) phenoxymethyl]-coumarins (4aee) were synthesized
at room temperature by stirring the reaction mixture of 4-fluo-
rophenol and anhydrous K2CO3 with various 4-bromomethyl
coumarins (3aee) in dry acetone. On the other hand the
All the products gave satisfactory analytical and spectro-
scopic data, which are in full accordance with their assigned
structures. The ORTEP diagram of one of the compounds,
7-methyl-4-[(40-fluoro)-anilinomethyl]-coumarin (5c), is re-
ported (Fig. 1). The various new compounds synthesized dur-
ing the present investigation are listed in Table 1.
O
O
O
1
liq-Br2
dry ether
stirr
Br
O
O
O
2
F
F
Subs.Phenols
Conc.H2SO4
0°-5°C
O
Br
NH
4-fluoro phenol
dry acetone
stirr
4-fluoro aniline
dry xylene
reflux
R
R
R
O
O
O
O
O
O
4
5
3
R = 6 - Cl, 6 - CH3, 7 - CH3, 5,6 - benzo, 7,8 - benzo
Scheme 1. Synthesis of new 4-fluoro-aryloxymethyl and aminomethyl coumarins.

2180
R.G. Kalkhambkar et al. / European Journal of Medicinal Chemistry 43 (2008) 2178e2188
O
O
R
N
H
6
liq-Br2
dry CHCl3
Stirr
O
O
R
Br
N
H
7
F
F
heat
Conc.H2SO4
Br
O
NH
4-fluoro phenol
dry alcohol
reflux
4-fluoro aniline
dry xylene
reflux
R
R
R
N
H
O
N
H
O
N
H
O
8
10
9
R = H, 6 - Cl, 7 - Cl, 8 - CH3
Scheme 2. Synthesis of new 4-fluoro-aryloxymethyl and aminomethyl 1-aza coumarins.
3. Pharmacology
3.1. Anti-microbial assay
Griseofulvin. The tests were carried out at a concentration of
100 mg mlꢁ1, 50 mg mlꢁ1, and 25 mg mlꢁ1. After 48 h of incuba-
tion at 37 ꢀC, the zone of inhibition was measured in milli-
metres. The percentage inhibition of test compounds was
related to the standard whose zone of inhibition was taken as
100%.
All the new fluorinated analogues of coumarin and 1-aza cou-
marin were tested for in-vitro anti-microbial activity by
cupeplate method [23e25]. Two bacterial microorganisms
Escherischia coli (Gram þve) and Bacillus cirrhosis (Gram
ꢁve) and the two fungal microorganisms Aspirgillus niger and
Rhizoctonia bataticola were used. DMF was used as a solvent
control and the standard drugs used were Norfloxacin and
3.2. Acute toxicity
Groups of six albino mice, weighing 20e25 g were fasted
overnight and treated per orally and intraperitoneally with
the test compounds [26,27]. The dosage was varied from
1000 mg kgꢁ1 to 100 mg kgꢁ1 body weights. The animals
were observed for 24 h for any signs of acute toxicity such
as increased or decreased motor activity, tremors, convulsion,
sedation, lacrimation etc. No mortality of the animals was ob-
served even after 24 h. Hence the LD50 cut off value of the test
compounds was fixed as 1000 mg kgꢁ1, so that 100 mg kgꢁ1
i.e., 1/10 of cut off value was taken as screening dose for
the evaluation of anti-inflammatory activity.
O3
O1
C5
C3
C1
C4
C8
C2
C6
C7
C11
C13
F1
C14
C15
C16
C9
N1
C10
3.2.1. Ulcerogenic activity
C12
Male Wistar rats were fasted for 36 h. Indomethacin sus-
pended in 1% CMC was given orally at a dose level of
20 mg kgꢁ1 (2 ꢂ 10 mg kgꢁ1) body weight and the test
C17
Fig. 1. ORTEP diagram of 7-methyl-4-[(40-fluoro)-anilinomethyl]-coumarin.

R.G. Kalkhambkar et al. / European Journal of Medicinal Chemistry 43 (2008) 2178e2188
2181
Table 1
List of the new fluorinated coumarins and carbostyrils synthesized (4ae10d)
method according to Winter et al. [9,31], by employing
3.5% of formalin as the phlogistic agent. All the test com-
pounds were administered orally as suspensions in 2%
CMC, 30 min before the injection of the phlogistic agent, at
a dose level of 100 mg kgꢁ1 body weight. Indomethacin was
used as a standard at a dose level of 10 mg kgꢁ1 body weight.
Groups of six Wistar rats of either sex were used in each ex-
periment. Plain CMC (2%) served as a control. The paw oe-
dema volume was measured with the help of
plethysmograph by mercury displacement method at 0 h (im-
mediately after injection of formalin), 1 h, 2 h, 3 h, 4 h and
5 h.
R'
Y
R
X
O
(4a-10d)
R
Sl. no.
Compounds
R0
X
Y
4. Results and discussion
1
4a
4b
6-Cl
40-F
40-F
40-F
40-Cl
40-Br
40-F
40-F
40-F
40-F
40-F
40-Cl
40-Br
40-F
40-F
40-F
40-F
40-Cl
40-Br
40-F
40-Cl
40-Br
40-F
40-Cl
40-Br
40-F
40-F
40-F
40-F
O
O
2
6-CH3
7-CH3
7-CH3
7-CH3
5,6-Benz
7,8-Benz
6-Cl
O
O
4.1. Anti-microbial activity
3
4c
O
O
4
4c1
4c2
4d
O
O
The standard cupeplate method [23e25] was adopted for
the determination of anti-bacterial and anti-fungal activities
of the new fluorinated coumarins and the corresponding
1-aza coumarins.
5
O
O
6
O
O
7
4e
5a
O
O
8
O
NH
NH
NH
NH
NH
NH
NH
O
9
5b
5c
6-CH3
7-CH3
7-CH3
7-CH3
5,6-Benz
7,8-Benz
H
O
The results of the anti-microbial activities of coumarin de-
rivatives (Table 2) show that 4-aryloxymethylcoumarins 4c,
4c1 and 4c2 with 7-CH3 substitution in coumarin ring and F,
Cl, Br at 4-position of the aryloxymethyl moiety, have shown
up to 60% activity against both the bacterial strains and fungal
strains at 100 mg mlꢁ1 concentration as compared to the stan-
dard. But at 25 mg mlꢁ1 concentration the activity is less than
20%. Hence further dilution was not taken up. Even in the case
of 5c, 5c1 and 5c2 with 7-CH3 group in coumarin ring and F,
Cl, and Br at 4-position of the arylaminomethyl moiety, a max-
imum of 70% activity was observed against both the bacterial
and fungal strains at 100 mg mlꢁ1 concentration and up to 20%
activity at 25 mg mlꢁ1 concentration as compared to the stan-
dard. Therefore only fluorinated aryloxymethyl and arylami-
nomethyl coumarins were used for further studies.
Compounds 4a and 5a have shown more than 90% activity
for both the bacterial and fungal strains at 100 mg mlꢁ1 con-
centration as compared to the standard. They were active up
to 60% even at 25 mg mlꢁ1 concentration. In general the 4-ar-
yloxymethyl and arylaminomethyl coumarin derivatives
showed stronger anti-bacterial activity, even at the 25 mg mlꢁ1
concentration and presence of fluorine at 4-position of both ar-
yloxymethyl and arylaminomethyl coumarin derivatives
showed better anti-microbial activity as compared to the cor-
responding 4-chloro and 4-bromo derivatives.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
O
5c1
5c2
5d
O
O
O
5e
9a
O
NH
NH
NH
NH
NH
NH
NH
NH
NH
NH
NH
NH
NH
NH
9b
6-Cl
6-Cl
O
9b1
9b2
9c
O
6-Cl
7-Cl
O
O
9c1
9c2
9d
7-Cl
7-Cl
O
O
8-CH3
8-CH3
8-CH3
H
O
9d1
9d2
10a
10b
10c
10d
O
O
NH
NH
NH
NH
6-Cl
7-Cl
8-CH3
compounds were administered twice at 2 h interval at a dose
level of 400 mg kgꢁ1 body weight. The animals were sacrificed
after 4 h and stomach was examined for lesions. The compounds
showed low or no harmful effects. Indomethacin at lower doses
produced serious gastric ulcers in all animals [28].
3.2.2. Analgesic activity
The analgesic activity of the test compounds was deter-
mined in-vivo by using abdominal constriction test induced
by acetic acid 0.6% (0.1 ml 10 gꢁ1) in mice [29,30]. Albino
mice of both sexes (18e22 g) were used. Compounds were ad-
ministered orally (10 mg kgꢁ1) as a suspension in 5% carboxy
methyl cellulose (vehicle). Indomethacin (10 mg kgꢁ1) was
used as the standard drug under the same conditions.
Similarly in the anti-microbial activities of 1-aza coumarin
derivatives (Table 3), it was observed that the 4-aryloxy-
methyl-1-aza coumarin 9b, with 6-Cl substitution showed
81% growth inhibition for both bacterial and fungal strains
at 100 mg mlꢁ1 concentration as compared to 50e60% activity
of the corresponding chloro and bromo substituents in the ar-
yloxy moiety (9b1 and 9b2, respectively). Further it was ob-
served that compound 9b retained up to 45% activity even
at 25 mg mlꢁ1 concentration, whereas the other two derivatives
were inactive at that concentration. Similarly 9c with 7-Cl and
40-F substitution showed about 78% anti-bacterial activity and
3.2.3. Anti-inflammatory activity
The anti-inflammatory activity of the test compounds was
determined by formalin induced rat-paw oedema inhibition

2182
R.G. Kalkhambkar et al. / European Journal of Medicinal Chemistry 43 (2008) 2178e2188
Table 2
Anti-bacterial and anti-fungal activities of selected coumarins
Compounds R
R0
Zone of inhibition mm, %
Bacteria
Fungi
E. coli Concentration, mg/ml B. cirrhosis Concentration, mg/ml A. niger Concentration, mg/ml R. bataticola Concentration, mg/ml
100 mg 50 mg
25 mg 100 mg
50 mg
25 mg
100 mg
50 mg
25 mg
100 mg
50 mg
25 mg
4a
4c
6-Cl 40-F 238, 94 135, 60 92, 51 234, 97
148, 71
88, 37
84, 33
88, 37
150, 83
120, 55
82, 34
88, 37
200
110, 64
50, 21
40, 14
48, 20
110, 64
60, 28
44, 17
50, 21
160
216, 89 148, 71 106, 61 234, 89
168, 74
80, 30
75, 27
84, 32
172, 76
118, 49
84, 32
90, 35
220
118, 65
Nil, e
Nil, e
Nil, e
122, 68
60, 26
Nil, e
Nil, e
170
7-CH3 40-F 164, 62
7-CH3 40-Cl 170, 65
7-CH3 40-Br 172, 66
92, 37 44, 17 162, 64
88, 35 40, 14 158, 62
92, 37 48, 20 160, 63
136, 52
130, 50
138, 52
58, 21 Nil, e
60, 22 Nil, e
60, 22 Nil, e
148, 53
150, 54
158, 57
4c1
4c2
5a
5c1
6-Cl 40-F 240, 95 142, 64 92, 51 238, 99
7-CH3 40-F 188, 73 108, 46 58, 27 184, 74
220, 90 152, 73 110, 64 240, 91
168, 67
138, 52
142, 55
240
80, 33 40, 14
58, 21 Nil, e
62, 23 Nil, e
188, 70
150, 54
162, 59
260
5c2
5c3
7-CH3 40-Cl 164, 62
7-CH3 40-Br 168, 64
90, 36 44, 17 152, 60
88, 35 38, 13 160, 63
Standard
Control
e
e
e
e
250
20
210
20
160
20
240
20
200
20
160
20
20
20
20
20
20
20
Standards used e Norfloxacin, Gresofulvin e 100% inhibition at each concentration.
Control e dimethyl formamide.
higher anti-fungal activity, 85%, as compared to the 50e60%
activity of the corresponding chloro and bromo compounds
9c1 and 9c2. In the case of 4-anilinomethyl-1-aza coumarins,
10b and 10c, with 6-Cl and 7-Cl substituents, the compounds
have shown more than 75% activity against both the bacterial
and fungal strains, at 100 mg mlꢁ1 concentration as compared
to the standard. In general the fluorinated derivatives of 4-ar-
yloxymethyl and arylaminomethyl 1-aza coumarins showed
excellent anti-bacterial and anti-fungal activities up to 85%
as compared to the corresponding 4-chloro and 4-bromo deriv-
were watched for mortality and symptoms until eighth day
[26,27]. It is found that all the compounds possess good safety
profile till the highest dose. No mortality of animals was ob-
served even after 24 h.
4.3. Ulcerogenic activity
The ulcer index of the test compounds (Table 4) showed no
harmful effects on the stomach, at the dose of 400 mg kgꢁ1
p.o, in fasted rats. Indomethacin at lower doses produced seri-
ous gastric ulcers in all animals [28].
atives. At lower concentrations coumarins were found to be
more active than 1-aza coumarins.
The graphical representation of anti-microbial activities of
selected coumarins and 1-aza coumarins at 100 mg mlꢁ1 con-
centration is depicted in Fig. 2.
4.4. Analgesic activity
Abdominal constriction response induced by acetic acid is
a sensitive procedure to establish efficacy of peripherally act-
ing analgesics. Intraperitoneal administration of acetic acid
causes increase in the level of PGE2 and PGF 2a [29,30].
The results of analgesic activity (Table 4) indicate that com-
pounds 5e and 4b showed highest analgesic activity of 76%
4.2. Acute toxicity studies
The acute toxicity studies of the test compounds (Table 4)
were performed on albino mice fasted for 24 h. The animals
Table 3
Anti-bacterial and anti-fungal activities of selected 1-aza coumarins
Compounds R
R0
Zone of inhibition mm, %
Bacteria
Fungi
E. coli Concentration, mg/ml B. cirrhosis Concentration, mg/ml A. niger Concentration, mg/ml R. bataticola Concentration, mg/ml
100 mg 50 mg
25 mg
100 mg
50 mg
25 mg
100 mg
50 mg
25 mg
100 mg
50 mg
25 mg
9b
6-Cl 40-F 216, 81 144, 62 88, 45 204, 80
118, 51
80, 31
68, 25
96, 40
68, 25
70, 26
80, 31
88, 36
98, 41
104, 44
210
60, 28
Nil, e
Nil, e
52, 22
Nil, e
Nil, e
Nil, e
Nil, e
52, 22
58, 27
160
186, 75 104, 44 62, 29 222, 84
150, 68
84, 33
82, 32
158, 72
78, 35
80, 31
90, 36
90, 36
128, 56
138, 62
210
90, 50
Nil, e
Nil, e
98, 55
Nil, e
Nil, e
50, 21
50, 21
82, 44
88, 48
160
9b1
9b2
9c
6-Cl 40-Cl 142, 50
6-Cl 40-Br 140, 50
80, 30 Nil, e 158, 60
82, 30 Nil, e 154, 58
138, 53 68, 25 Nil, e 152, 55
158, 62 90, 36 50, 21 152, 55
194, 79 110, 47 68, 34 228, 86
7-Cl 40-F 209, 78 132, 56 72, 34 196, 76
9c1
9c2
7-Cl 40-Cl 136, 48
7-Cl 40-Br 140, 50
8-CH3 40-F 158, 57
76, 27 Nil, e 150, 56
80, 30 Nil, e 158, 60
86, 33 Nil, e 164, 62
92, 34 Nil, e 166, 68
132, 50
154, 60
154, 60
160, 63
60, 21 Nil, e 144, 51
88, 35 46, 18 150, 54
90, 36 52, 22 160, 58
98, 41 54, 24 164, 60
9d
10a
H
40-F 158, 57
10b
10c
6-Cl 40-F 188, 70 120, 50 60, 26 196, 76
7-Cl 40-F 196, 73 128, 54 68, 32 200, 78
190, 77 110, 47 70, 35 200, 75
198, 80 118, 52 78, 41 210, 79
Standard
Control
e
e
e
e
260
20
220
20
170
20
250
20
240
20
210
20
160
20
260
20
20
20
20
20
Standards used e Norfloxacin, Gresofulvin e 100% inhibition at each concentration.
Control e dimethyl formamide.

R.G. Kalkhambkar et al. / European Journal of Medicinal Chemistry 43 (2008) 2178e2188
2183
and 4a showed maximum of 83%, 81% and 80% inhibition
of inflammation, respectively, at the end of the fifth hour. Sim-
ilarly 1-aza coumarin derivatives 10d and 9b showed 85% and
80% inhibition of inflammation, respectively, at the end of
fifth hour and the activity was as good as the standard and it
is interesting to note that the presence of fluorine at 40-position
induces better activity than the other halogenated compounds.
5. Conclusion
The present study has shown that the introduction of fluo-
rine at the 40-position in the aryloxy and arylamino moieties
of both coumarin and 1-aza-coumarin enhances the anti-mi-
crobial as well as analgesic and anti-inflammatory activities,
which might serve as new templates in the synthesis and de-
velopment of potent therapeutics. Our findings will have
a good impact on chemists and biochemists for further inves-
tigations in this field in search of fluorine containing anti-
microbial, analgesic and anti-inflammatory agents.
Fig. 2. The anti-microbial activities of selected fluoro coumarins and 1-aza
coumarins. Columns represent the % inhibition of selected compounds for
bacteria and fungi at 100 mg mlꢁ1 concentration. B.c (B. cirrhosis), A.n
(A. niger), R.b (R. bataticola), E.c (E. coli).
and 72%, respectively. Compounds 10d, 9c and 4a showed
66%, 61% and 56% inhibition of writhing, respectively, higher
than the standard and most of the compounds showed moder-
ate analgesic activity when compared to the control and the
standard group.
6. Experimental protocol
The melting points of the products were determined by
open capillaries on a Buchi apparatus and are uncorrected.
The IR spectra were recorded on a Nicolet Impact-410 FT-
4.5. Anti-inflammatory activity
1
IR Spectrophotometer, using KBr pellets. H NMR and 13C
The anti-inflammatory activity of the test compounds was
determined by formalin induced rat-paw oedema method
[9,31]. The results of anti-inflammatory activity (Table 5) in-
dicate that most of the compounds showed an extremely sig-
nificant anti-inflammatory activity when compared to the
control and the standard group. Coumarin derivatives 5c, 5e
NMR spectra were recorded on a Bruker AC-300F 300 MHz
spectrometer in CDCl3 using TMS as an internal standard
with 1H resonant frequency of 300 MHz and 13C resonant fre-
quency of 75 MHz. D2O exchange was applied to confirm the
assignment of the signals of NH protons. 19F NMR spectra
were obtained on a Bruker AV 500 MHz spectrometer using
CF3COOH (TFA) as an external standard, positive for down-
field shift with 19F resonant frequency of 470 MHz. Mass
spectra were recorded on an Autospec EI-MS and FAB-MS.
Elemental analysis was carried out by using Heraus CHN
rapid analyzer. All the compounds gave C, H and N analysis
within ꢃ0.4% of the theoretical values. The homogeneity of
the compounds was described by TLC on aluminum silica
gel 60 F254 (Merck) detected by UV light (254 nm) and iodine
vapours. The reagents were all of analytical reagent-grade or
chemically pure. All solvents were dried, deoxygenated and
redistilled before use.
Table 4
Analgesic activities, ulcerogenic and acute toxicity studies of the test
compounds
Compounds
Analgesic activity,a
% inhibition of
writhing
Ulcerogenic
score,b
Acute toxicity
LD50, mg kgꢁ1
400 mg kgꢁ1
i.p
p.o
4a
4b
56.21
72.72
23.18
3.96
66.66
57.29
61.80
64.93
64.93
64.93
60.71
71.42
67.5
>700
>700
>800
>800
>800
>700
>800
>800
>800
>700
>700
>700
w15
e
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
w25
4e
5c
5d
5e
10.5
76.42
15.84
26.9
9a
9b
6.1. General procedure for the preparation of
compounds 4aee
9c
61.27
7.99
10b
10c
10d
Standard
Control
58.57
61.42
55.35
185.14
e
28.57
66.97
46.22
e
A mixture of substituted 4-bromomethyl coumarins (3aee)
(4.0 mmol), 4-fluoro-phenol (4.0 mmol) and powdered anhy-
drous potassium carbonate (4.0 mmol) in super dry acetone
(20 ml) was stirred at room temperature for 16 h; after com-
pletion of the reaction, the separated solid was filtered, washed
with 20% HCl and with excess of cold water, dried and crys-
tallized from suitable solvent.
e
Oral administration for all the test compounds at a dose level of 10 mg kgꢁ1
body weight.
a
Standard used e Indomethacin e 10 mg kgꢁ1
Standard used e Indomethacin e 2 ꢂ 10 mg kgꢁ1
.
b
.

2184
R.G. Kalkhambkar et al. / European Journal of Medicinal Chemistry 43 (2008) 2178e2188
Table 5
Anti-inflammatory activities of the test compounds (formalin induced rat-paw oedema method)
Compounds
Anti-inflammatory activity
Oedema volume at different time intervals ꢃ SEM (% inhibition)
1 h
2 h
3 h
4 h
0.55 ꢃ 0.08 (71)
5 h
0.4 ꢃ 0.09 (80)
4a
4b
0.48 ꢃ 0.04 (39)
0.87 ꢃ 0.04 (38)
0.77 ꢃ 0.05 (58)
0.45 ꢃ 0.07 (40)
0.43 ꢃ 0.06 (46)
0.30 ꢃ 0.03 (62)
0.29 ꢃ 0.03 (63)
0.15 ꢃ 0.02 (81)
0.55 ꢃ 0.07 (35)
0.48 ꢃ 0.04 (39)
0.6 ꢃ 0.02 (24)
0.72 ꢃ 0.03 (9)
0.76 ꢃ 0.04 (4)
0.61 ꢃ 0.04 (23)
0.51 ꢃ 0.03 (35)
0.79 ꢃ 0.010 (0)
0.89 ꢃ 0.11 (36)
0.98 ꢃ 0.08 (30)
0.88 ꢃ 0.07 (37)
0.92 ꢃ 0.04 (35)
0.64 ꢃ 0.06 (54)
1.11 ꢃ 0.06 (23)
1.01 ꢃ 0.07 (28)
1.06 ꢃ 0.03 (24)
1.23 ꢃ 0.05 (12)
1.35 ꢃ 0.05 (4)
1.01 ꢃ 0.04 (28)
0.8 ꢃ 0.05 (43)
1.40 ꢃ 0.013 (0)
0.95 ꢃ 0.1 (48)
1.0 ꢃ 0.06 (45)
0.83 ꢃ 0.08 (54)
0.85 ꢃ 0.07 (53)
0.86 ꢃ 0.07 (53)
0.88 ꢃ 0.04 (52)
0.78 ꢃ 0.08 (57)
0.83 ꢃ 0.04 (54)
0.98 ꢃ 0.03 (46)
1.06 ꢃ 0.08 (42)
1.71 ꢃ 0.06 (6)
0.55 ꢃ 0.05 (75)
1.82 ꢃ 0.013 (0)
0.68 ꢃ 0.04 (64)
0.76 ꢃ 0.05 (66)
0.64 ꢃ 0.08 (67)
0.64 ꢃ 0.08 (60)
0.56 ꢃ 0.09 (71)
0.71 ꢃ 0.06 (63)
0.55 ꢃ 0.08 (71)
0.65 ꢃ 0.02 (66)
0.78 ꢃ 0.04 (59)
0.81 ꢃ 0.08 (57)
0.51 ꢃ 0.07 (73)
0.46 ꢃ 0.06 (76)
1.91 ꢃ 0.011 (0)
0.48 ꢃ 0.04 (76)
0.51 ꢃ 0.06 (75)
0.35 ꢃ 0.04 (83)
0.46 ꢃ 0.06 (77)
0.38 ꢃ 0.08 (81)
0.46 ꢃ 0.03 (77)
0.4 ꢃ 0.06 (80)
0.45 ꢃ 0.03 (78)
0.46 ꢃ 0.03 (77)
0.46 ꢃ 0.06 (77)
0.31 ꢃ 0.07 (85)
0.3 ꢃ 0.02 (85)
2.02 ꢃ 0.01 (0)
4e
5c
5d
5e
9a
9b
9c
10b
10c
10d
Standard
Control
Oral administration of the test compounds, at a dose level of 100 mg kgꢁ1 body weight.
Standard used e Indomethacin e 10 mg kgꢁ1
.
The data are analyzed by one-way ANOVA followed by Tukey comparison of all pairs.
Model e acute inflammation.
Method e formalin induced.
6.1.1. 6-Chloro-4-[(40-fluoro) phenoxymethyl]-
coumarin (4a)
19.00; 19F NMR (470 MHz, CDCl3, d ppm): ꢁ125.82 (s, 1F,
C40eF); EI-MS: m/z 284 (Mþ). Anal. Calc. for C17H13FO3:
C, 71.80; H, 4.58; found: C, 71.40; H, 4.24%.
Yield: 72%; light green crystaꢁls1 (ethanol); m.p. 205e
207 ꢀC; IR (KBr): 1728, 1150 cm
;
1H NMR (300 MHz,
CDCl3, d ppm): 5.40 (s, 2H, C4eCH2), 6.30 (s, 1H, C3eH),
6.50e7.80 (m, 7H, Ar-H); 13C NMR (75 MHz CDCl3,
d ppm): 161.50, 158.28, 156.34, 154.28, 136.89, 133.48,
132.80, 127.08, 124.60, 119.40, 116.30, 116.21, 114.47,
114.30, 109.10, 65.98; 19F NMR (470 MHz, CDCl3, d ppm):
ꢁ123.62 (s, 1F, C40eF); EI-MS: m/z 304 (Mþ). Anal. Calc.
for C16H10ClFO3: C, 63.07; H, 3.31; found: C, 62.87; H, 3.61%.
6.1.4. 7-Methyl-4-[(40-chloro) phenoxymethyl]-
coumarin (4c1)
Yield: 78%; colorless crystals (ethanol þ dioxan); m.p.
181e183 ꢀC; IR (KBr): 1701, 3032, 1152 cmꢁ1 1H NMR
;
(300 MHz, CDCl3, d ppm): 2.45 (s, 3H, C7eCH3), 5.22 (s,
2H, C4eCH2), 6.55 (s, 1H, C3eH), 6.94e7.41 (m, 7H, Ar-
H); 13C NMR (75 MHz, CDCl3, d ppm): 161.38, 159.24,
156.77, 155.24, 151.10, 137.80, 127.89, 126.74, 124.30,
122.88, 116.14, 116.18, 114.23, 114.04, 109.17, 65.48,
18.00; EI-MS: m/z 300 (Mþ). Anal. Calc. for C17H13ClO3:
C, 68.00; H, 4.33; found: C, 67.80; H, 4.24%.
6.1.2. 6-Methyl-4-[(40-fluoro) phenoxymethyl]-
coumarin (4b)
Yield: 85%; colorless crystals (ethanol þ dioxan); m.p.
188e190 ꢀC; IR (KBr): 1733, 1145 cmꢁ1
;
1H NMR
(300 MHz, CDCl3, d ppm): 2.45 (s, 3H, C6eCH3), 5.21 (s,
2H, C4eCH2), 6.67 (s, 1H, C3eH), 6.95e7.41 (m, 7H, Ar-
H); 13C NMR (75 MHz, CDCl3, d ppm): 162.18, 159.04,
156.80, 155.50, 151.08, 138.70, 127.03, 126.90, 124.24,
122.17, 116.50, 116.41, 114.44, 114.20, 109.20, 65.30,
18.90; 19F NMR (470 MHz, CDCl3, d ppm): ꢁ124.34 (s, 1F,
C40eF); EI-MS: m/z 284 (Mþ). Anal. Calc. for C17H13FO3:
C, 71.80; H, 4.57; found: C, 71.46; H, 4.29%.
6.1.5. 7-Methyl-4-[(40-bromo) phenoxymethyl]-
coumarin (4c2)
Yield: 80%; colorless crystals (ethanol þ dioxan); m.p.
176e178 ꢀC; IR (KBr): 1708, 3040, 1146 cmꢁ1 1H NMR
;
(300 MHz, CDCl3, d ppm): 2.38 (s, 3H, C7eCH3), 5.30 (s,
2H, C4eCH2), 6.48 (s, 1H, C3eH), 6.92e7.48 (m, 7H, Ar-
H); 13C NMR (75 MHz, CDCl3, d ppm): 162.50, 158.90,
156.80, 155.24, 151.10, 138.80, 127.89, 126.74, 124.30,
122.88, 116.14, 116.20, 114.23, 114.04, 109.17, 65.48,
19.04; EI-MS: m/z 345 (Mþ). Anal. Calc. for C17H13BrO3:
C, 59.31; H, 3.76; found: C, 59.09; H, 3.50%.
6.1.3. 7-Methyl-4-[(40-fluoro)phenoxymethyl]-coumarin(4c)
Yield: 80%; colorless crystals (ethanol þ dioxan); m.p.
194e196 ꢀC; IR (KBr): 1720, 1140 cmꢁ1
;
1H NMR
(300 MHz, CDCl3, d ppm): 2.48 (s, 3H, C7eCH3), 5.20 (s,
2H, C4eCH2), 6.45 (s, 1H, C3eH), 6.52e7.63 (m, 7H, Ar-
H); 13C NMR (75 MHz, CDCl3, d ppm): 162.30, 159.20,
156.77, 155.24, 151.10, 137.78, 126.89, 126.54, 124.30,
122.80, 116.14, 116.10, 114.23, 114.04, 109.17, 65.44,
6.1.6. 5,6-Benzo-4-[(40-fluoro) phenoxymethyl]-
coumarin (4d)
Yield: 86%; pale yellow crystals (ethanol þ dioxan); m.p.
168e170 ꢀC; IR (KBr): 1717, 1147 cmꢁ1
;
1H NMR

R.G. Kalkhambkar et al. / European Journal of Medicinal Chemistry 43 (2008) 2178e2188
2185
(300 MHz, CDCl3, d ppm): 5.38 (s, 2H, C4eCH2), 6.64 (s,
1H, C3eH), 6.94e8.50 (m, 10H, Ar-H); 13C NMR
(75 MHz, CDCl3, d ppm): 162.08, 159.78, 158.51, 153.80,
148.21, 133.40, 132.70, 127.06, 123.60, 122.34, 121.80,
120.41, 119.40, 118.28, 116.50, 116.31, 114.70, 114.56,
109.28, 66.04; 19F NMR (470 MHz, CDCl3, d ppm):
ꢁ122.61 (s, 1F, C40eF); EI-MS: m/z 320 (Mþ). Anal. Calc.
for C20H13FO3: C, 74.99; H, 4.09; found: C, 74.50; H, 3.80%.
6.2.3. 7-Methyl-4-[(40-fluoro) anilinomethyl]-coumarin (5c)
Yield: 88%; colorless crystals (ethanol); m.p. 141e143 ꢀC;
IR (KBr): 1718, 3348, 1145.1 cmꢁ1 1H NMR (300 MHz,
;
CDCl3, d ppm): 2.47 (s, 3H, C7eCH3), 4.17 (s, 1H, CH2NH ),
4.50 (s, 2H, C4eCH2), 6.25 (s, 1H, C3eH), 6.48e9.02 (m,
7H, Ar-H); 13C NMR (75 MHz, CDCl3, d ppm): 162.40,
159.30, 157.03, 149.29, 142.30, 134.60, 129.07, 128.90,
126.14, 121.14, 116.12, 116.03, 112.70, 112.61, 109.20,
63.18, 19.83; 19F NMR (470 MHz, CDCl3, d ppm): ꢁ126.64
(s, 1F, C40eF); EI-MS: m/z 283 (Mþ). Anal. Calc. for
C17H14FNO2: C, 72.07; H, 4.98; N, 4.94; found: C, 71.88;
H, 4.54; N, 4.79%.
6.1.7. 7,8-Benzo-4-[(40-fluoro) phenoxymethyl]-
coumarin (4e)
Yield: 88%; light green crystaꢁls1 (ethanol); m.p. 240e
242 ꢀC; IR (KBr): 1702, 1161 cm
;
1H NMR (300 MHz,
6.2.4. 7-Methyl-4-[(40-chloro) anilinomethyl]-
coumarin (5c1)
CDCl3, d ppm): 5.25 (s, 2H, C4eCH2), 6.45 (s, 1H, C3eH),
6.90e8.22 (m, 10H, Ar-H); 13C NMR (75 MHz, CDCl3,
d ppm): 163.10, 159.08, 158.16, 153.20, 146.81, 133.14,
132.70, 128.44, 126.40, 126.20, 124.17, 122.80, 121.08,
119.80, 116.54, 116.38, 114.70, 112.30, 108.80, 66.21; 19F
NMR (470 MHz, CDCl3, d ppm): ꢁ128.69 (s, 1F, C40eF);
EI-MS: m/z 320 (Mþ). Anal. Calc. for C20H13FO3: C, 74.99;
H, 4.09; found: C, 74.55; H, 3.92%.
Yield: 76%; colorless crystals (ethanol þ dioxan); m.p.
200e202 ꢀC; IR (KBr): 3342, 1725, 1142 cmꢁ1 1H NMR
;
(300 MHz, CDCl3, d ppm): 2.38 (s, 3H, C7eCH3), 4.10 (s,
1H, CH2NH ), 4.48 (s, 2H, C4eCH2), 6.28 (s, 1H, C3eH),
6.50e9.10 (m, 7H, Ar-H); 13C NMR (75 MHz, CDCl3,
d ppm): 161.80, 159.58, 158.00, 149.24, 142.30, 134.60,
129.07, 128.90, 126.14, 121.14, 116.12, 116.00, 112.70,
112.61, 109.28, 63.34, 18.90; EI-MS: m/z 299 (Mþ). Anal.
Calc. for C17H14ClNO2: C, 68.22; H, 4.68; N, 4.68; found:
C, 68.00; H, 4.54; N, 4.43%.
6.2. General procedure for the preparation of
compounds 5aee
A mixture of substituted 4-bromomethyl coumarins (3aee)
(4.0 mmol) and 4-fluoro-aniline (4.0 mmol) in super dry xy-
lene (20 ml) was refluxed on an oil bath for 8 h (135e
148 ꢀC). After the completion of the reaction, the separated
solid was filtered, washed with excess of cold ethanol, dried
and crystallized from suitable solvent.
6.2.5. 7-Methyl-4-[(40-bromo) anilinomethyl]-
coumarin (5c2)
Yield: 80%; colorless crystals (ethanol þ dioxan); m.p.
230e232 ꢀC; IR (KBr): 3350, 1712, 1158 cmꢁ1 1H NMR
;
(300 MHz, CDCl3, d ppm): 2.42 (s, 3H, C7eCH3), 4.10 (s,
1H, CH2NH ), 4.62 (s, 2H, C4eCH2), 6.38 (s, 1H, C3eH),
6.48e9.08 (m, 7H, Ar-H); 13C NMR (75 MHz, CDCl3,
d ppm): 162.88, 159.00, 157.43, 149.29, 142.30, 134.60,
129.00, 128.90, 126.14, 121.14, 116.12, 116.03, 112.70,
112.61, 109.20, 63.00, 18.25; EI-MS: m/z 344 (Mþ). Anal.
Calc. for C17H14BrNO2: C, 59.30; H, 4.06; N, 4.06; found:
C, 59.18; H, 3.94; N, 3.83%.
6.2.1. 6-Chloro-4-[(40-fluoro) anilinomethyl]-coumarin (5a)
Yield: 78%; colorless crystals (ethanol þ dioxan); m.p.
238e240 ꢀC; IR (KBr): 1709, 3376, 1184 cmꢁ1 1H NMR
;
(300 MHz, CDCl3, d ppm): 4.14 (s, 1H, CH2NH ), 4.56 (s,
2H, C4eCH2), 6.30 (s, 1H, C3eH), 6.50e8.90 (m, 7H, Ar-
H); 13C NMR (75 MHz, CDCl3, d ppm): 161.48, 159.14,
156.66, 150.30, 138.92, 131.26, 129.50, 128.80, 127.17,
122.80, 116.30, 116.21, 113.98, 112.20, 108.76, 62.70; 19F
NMR (470 MHz, CDCl3, d ppm): ꢁ124.83 (s, 1F, C40eF);
EI-MS: m/z 303 (Mþ). Anal. Calc. for C16H11ClFNO2: C,
63.27; H, 3.65; N, 4.61; found: C, 63.36; H, 3.38; N, 4.50%.
6.2.6. 5,6-Benzo-4-[(40-fluoro) anilinomethyl]-
coumarin (5d)
Yield: 92%; yellow crystals (ethanol þ dioxꢁan1); m.p. 210e
212 ꢀC; IR (KBr): 1700, 3363, 1150 cm
;
1H NMR
(300 MHz, CDCl3, d ppm): 4.35 (s, 1H, CH2NH ), 4.92 (s,
2H, C4eCH2), 6.43 (s, 1H, C3eH), 6.50e8.30 (m, 10H, Ar-
H); 13C NMR (75 MHz, CDCl3, d ppm): 161.88, 158.60,
154.38, 151.71, 140.11, 131.68, 130.90, 128.20, 127.90,
126.12, 123.21, 118.13, 117.90, 116.28, 116.21, 113.22,
113.18, 112.80, 108.60, 62.76; 19F NMR (470 MHz, CDCl3,
d ppm): ꢁ122.64 (s, 1F, C40eF); EI-MS: m/z 319 (Mþ).
Anal. Calc. for C20H14FNO2: C, 75.22; H, 4.42; N, 4.39;
found: C, 74.84; H, 4.10; N, 4.09%.
6.2.2. 6-Methyl-4-[(40-fluoro) anilinomethyl]-coumarin (5b)
Yield: 82%; colorless crystals (ethanol þ dioxan); m.p.
215e217 ꢀC; IR (KBr): 1702, 3369, 1166 cmꢁ1 1H NMR
;
(300 MHz, CDCl3, d ppm): 2.45 (s, 3H, C6eCH3), 4.15 (s,
1H, CH2NH ), 4.50 (s, 2H, C4eCH2), 6.32 (s, 1H, C3eH),
6.58e8.40 (m, 7H, Ar-H); 13C NMR (75 MHz, CDCl3,
d ppm): 162.14, 158.20, 156.48, 148.31, 140.93, 134.50,
128.17, 128.10, 126.30, 121.41, 116.31, 116.20, 112.90,
112.81, 109.40, 63.10, 20.13; 19F NMR (470 MHz, CDCl3,
d ppm): ꢁ123.82 (s, 1F, C40eF); EI-MS: m/z 283 (Mþ).
Anal. Calc. for C17H14FNO2: C, 72.07; H, 4.98; N, 4.94;
found: C, 71.81; H, 4.60; N, 4.78%.
6.2.7. 7,8-Benzo-4-[(40-fluoro) anilinomethyl]-
coumarin (5e)
Yield: 90%; yellow crystals (ethanol þ dioxꢁan1); m.p. 202e
204 ꢀC; IR (KBr): 1720, 3338, 1140 cm
;
1H NMR

2186
R.G. Kalkhambkar et al. / European Journal of Medicinal Chemistry 43 (2008) 2178e2188
(300 MHz, CDCl3, d ppm): 4.32 (s, 1H, CH2NH ), 4.90 (s, 2H,
C4eCH2), 6.46 (s, 1H, C3eH), 6.62e8.34 (m, 10H, Ar-H);
13C NMR (75 MHz, CDCl3, d ppm): 162.10, 158.17, 155.14,
150.90, 141.34, 132.08, 130.87, 128.23, 127.80, 126.06,
125.94, 123.20, 119.20, 118.71, 116.10, 116.02, 113.71,
113.52, 108.14, 62.30; 19F NMR (470 MHz, CDCl3, d ppm):
ꢁ128.67 (s, 1F, C40eF); EI-MS: m/z 319 (Mþ). Anal. Calc.
for C20H14FNO2: C, 75.22; H, 4.42; N, 4.39; found: C,
74.90; H, 4.14; N, 4.20%.
6.3.4. 6-Chloro-4-[(40-bromo) phenoxymethyl]-1-aza
coumarin (9b2)
Yield: 75%; colorless crystals (acetic aciꢁd)1; m.p. 270e
272 ꢀC; IR (KBr): 1655, 3419, 1147 cm
;
1H NMR
(300 MHz, CDCl3, d ppm): 5.45 (s, 2H, C4eCH2), 6.88e
7.95 (m, 8H, Ar-H), 11.86 (s, 1H, NH); 13C NMR (75 MHz,
CDCl3, d ppm): 161.88, 159.48, 156.96, 151.87, 137.00,
132.74, 129.46, 128.08, 125.95, 123.61, 116.60, 116.20,
114.66, 114.80, 109.04, 65.88; FAB-MS: m/z 365 (M þ H).
Anal. Calc. for C16H11ClBrNO2: C, 52.74; H, 3.02; N, 3.84;
found: C, 52.50; H, 2.88; N, 3.61%.
6.3. General procedure for the preparation of
compounds 9aed
6.3.5. 7-Chloro-4-[(40-fluoro) phenoxymethyl]-1-aza
coumarin (9c)
A mixture of substituted 4-bromomethylcarbostyril (8aed)
(4.0 mmol), 40-fluoro-phenol (4.0 mmol) and powdered anhy-
drous potassium carbonate (4.0 mmol) in super dry alcohol
(20 ml) was refluxed on a water bath for 10 h. After the com-
pletion of the reaction, the separated solid was filtered, washed
with 20% HCl and with excess of cold water, dried and crys-
tallized from suitable solvent.
Yield: 72%; colorless crystals (ethanol þ dioxan); m.p.
200e202 ꢀC; IR (KBr): 1659, 3425, 1120 cmꢁ1 1H NMR
;
(300 MHz, CDCl3, d ppm): 5.55 (s, 2H, C4eCH2), 6.44 (s,
1H, C3eH), 6.95e8.00 (m, 7H, Ar-H), 11.88 (s, 1H, NH);
13C NMR (75 MHz, CDCl3, d ppm): 161.21, 158.40, 156.30,
151.17, 135.90, 132.60, 129.86, 128.00, 126.10, 123.60,
116.40, 116.20, 114.80, 114.74, 110.01, 66.21; 19F NMR
(470 MHz, CDCl3, d ppm): ꢁ123.21 (s, 1F, C40eF); FAB-
MS: m/z 304 (M þ H). Anal. Calc. for C16H11FClNO2: C,
63.27; H, 3.65; N, 4.61; found: C, 63.14; H, 3.78; N, 4.33%.
6.3.1. 4-[(40-Fluoro) phenoxymethyl]-1-aza coumarin (9a)
Yield: 70%; colorless crystals (ethanol þ dioxan); m.p.
230e232 ꢀC; IR (KBr): 1665, 3431, 1140 cmꢁ1 1H NMR
;
(300 MHz, CDCl3, d ppm): 5.32 (s, 2H, C4eCH2), 6.95e
7.88 (m, 9H, Ar-H), 12.37 (s, 1H, NH); 13C NMR (75 MHz,
CDCl3, d ppm): 160.21, 158.51, 156.67, 153.67, 136.38,
133.78, 132.89, 126.15, 123.66, 118.38, 116.47, 116.38,
114.69, 114.58, 108.90, 66.74; 19F NMR (470 MHz, CDCl3,
d ppm): ꢁ122.94 (s, 1F, C40eF); FAB-MS: m/z 270(M þ H).
Anal. Calc. for C16H12FNO2: C, 71.37; H, 4.49; N, 5.20;
found: C, 71.07; H, 4.80; N, 5.23%.
6.3.6. 7-Chloro-4-[(40-chloro) phenoxymethyl]-1-aza
coumarin (9c1)
Yield: 78%; colorless crystals (acetic aciꢁd)1; m.p. 230e
232 ꢀC; IR (KBr): 1658, 3428, 1128 cm
;
1H NMR
(300 MHz, CDCl3, d ppm): 5.35 (s, 2H, C4eCH2), 6.94e
7.76 (m, 7H, Ar-H), 11.85 (s, 1H, NH); 13C NMR (75 MHz,
CDCl3, d ppm): 160.00, 158.32, 156.38, 151.20, 135.90,
132.60, 129.86, 128.09, 126.10, 123.60, 116.44, 116.20,
114.80, 114.74, 110.11, 66.18; FAB-MS: m/z 320 (M þ H).
Anal. Calc. for C16H11Cl2NO2: C, 60.18; H, 3.44; N, 4.38;
found: C, 60.10; H, 3.18; N, 4.04%.
6.3.2. 6-Chloro-4-[(40-fluoro) phenoxymethyl]-1-aza
coumarin (9b)
Yield: 78%; colorless crystals (ethanol þ dioxan); m.p.
240e242 ꢀC; IR (KBr): 1672, 3440, 1130 cmꢁ1 1H NMR
;
(300 MHz, CDCl3, d ppm): 5.28 (s, 2H, C4eCH2), 6.35 (s,
1H, C3eH), 6.88e7.90 (m, 7H, Ar-H), 11.95 (s, 1H, NH);
13C NMR (CDCl3, d ppm): 161.00, 159.34, 156.19, 151.87,
136.31, 132.74, 129.76, 127.31, 125.95, 123.61, 116.59,
116.19, 114.96, 114.84, 109.04, 66.32; 19F NMR (300 MHz,
CDCl3, d ppm): ꢁ123.68 (s, 1F, C40eF); FAB-MS: m/z 304
(M þ H). Anal. Calc. for C16H11FClNO2: C, 63.27; H, 3.65;
N, 4.61; found: C, 63.10; H, 3.80; N, 4.31%.
6.3.7. 7-Chloro-4-[(40-bromo) phenoxymethyl]-1-aza
coumarin (9c2)
Yield: 78%; colorless crystals (ethanol); m.p. 191e193 ꢀC;
IR (KBr): 1668, 3424, 1128 cmꢁ1 1H NMR (300 MHz,
;
CDCl3, d ppm): 5.18 (s, 2H, C4eCH2), 6.53e8.04 (m, 7H,
Ar-H), 11.94 (s, 1H, NH); 13C NMR (75 MHz, CDCl3,
d ppm): 161.22, 159.20, 156.38, 151.20, 135.90, 132.60,
128.66, 128.09, 126.10, 123.60, 116.44, 115.80, 114.80,
114.74, 110.11, 67.04; FAB-MS: m/z 365 (M þ H). Anal.
Calc. for C16H11ClBrNO2: C, 52.74; H, 3.02; N, 3.84; found:
C, 52.54; H, 2.78; N, 3.53%.
6.3.3. 6-Chloro-4-[(40-chloro) phenoxymethyl]-1-aza
coumarin (9b1)
Yield: 78%; colorless crystals (acetic aciꢁd)1; m.p. 250e
252 ꢀC; IR (KBr): 1660, 3434, 1140 cm
;
1H NMR
6.3.8. 8-Methyl-4-[(40-fluoro) phenoxymethyl]-1-aza
coumarin (9d)
(300 MHz, CDCl3, d ppm): 5.48 (s, 2H, C4eCH2), 6.70e
7.92 (m, 8H, Ar-H), 11.88 (s, 1H, NH); 13C NMR (75 MHz,
CDCl3, d ppm): 162.10, 159.44, 157.00, 151.87, 136.31,
132.74, 129.46, 127.31, 125.95, 123.61, 116.60, 116.19,
114.66, 114.84, 109.04, 66.40; FAB-MS: m/z 320 (M þ H).
Anal. Calc. for C16H11Cl2NO2: C, 60.18; H, 3.44; N, 4.38;
found: C, 60.00; H, 3.24; N, 4.10%.
Yield: 84%; colorless crystals (ethanol); m.p. 199e201 ꢀC;
IR (KBr): 1659, 3450, 1123 cmꢁ1 1H NMR (300 MHz,
;
CDCl3, d ppm): 2.60 (s, 3H, C8eCH3), 5.50 (s, 2H, C4e
CH2), 6.45 (s, 1H, C3eH), 6.98e7.98 (m, 7H, Ar-H), 11.80
(s, 1H, NH); 13C NMR (75 MHz, CDCl3, d ppm): 161.53,
159.69, 156.51, 153.66, 134.79, 134.11, 126.68, 125.78,

R.G. Kalkhambkar et al. / European Journal of Medicinal Chemistry 43 (2008) 2178e2188
2187
121.54, 120.24, 116.40, 116.14, 112.80, 114.14, 108.89, 66.82,
16.93; 19F NMR (470 MHz, CDCl3, d ppm): ꢁ124.23 (s, 1F,
C40eF); FAB-MS: m/z 284 (M þ H). Anal. Calc. for
C17H14FNO2: C, 72.07; H, 4.98; N, 4.94; found: C, 72.20;
H, 4.54; N, 4.80%.
CDCl3, d ppm): 4.10 (s, 1H, CH2NH ), 4.44 (s, 2H, C4e
CH2), 6.48 (s, 1H, C3eH), 6.88e7.48 (m, 7H, Ar-H), 8.78
(s, 1H, NHCO); 13C NMR (75 MHz, CDCl3, d ppm):
160.94, 158.48, 155.74, 148.17, 136.20, 133.18, 132.57,
126.10, 123.28, 115.40, 116.17, 116.08, 114.40, 114.32,
108.38, 63.54; 19F NMR (470 MHz, CDCl3, d ppm):
ꢁ122.20 (s, 1F, C40eF); FAB-MS: m/z 303 (M þ H). Anal.
Calc. for C16H12FClN2O: C, 63.48; H, 4.00; N, 9.25; found:
C, 63.57; H, 3.97; N, 9.07%.
6.3.9. 8-Methyl-4-[(40-chloro) phenoxymethyl]-1-aza
coumarin (9d1)
Yield: 80%; colorless crystals (ethanol þ dioxan); m.p.
236e238 ꢀC; IR (KBr): 1660, 3445, 1129 cmꢁ1 1H NMR
;
6.4.3. 7-Chloro-4-[(40-fluoro) anilinomethyl]-1-aza
coumarin (10c)
Yield: 70%; colorless crystals (acetic acid); m.p. 264e
(300 MHz, CDCl3, d ppm): 2.58 (s, 3H, C8eCH3), 5.52 (s,
2H, C4eCH2), 6.92e7.95 (m, 8H, Ar-H), 11.78 (s, 1H,
NH); 13C NMR (75 MHz, CDCl3, d ppm): 160.43, 159.60,
157.00, 153.78, 134.79, 134.90, 126.68, 125.78, 121.54,
120.64, 116.40, 116.14, 112.52, 114.14, 108.89, 67.52,
18.05; FAB-MS: 300 (M þ H). Anal. Calc. for C17H14ClNO2:
C, 68.22; H, 3.67; N, 4.68; found: C, 68.10; H, 3.44; N, 4.30%.
266 ꢀC; IR (KBr): 1659, 3369 cmꢁ1 1H NMR (300 MHz,
;
CDCl3, d ppm): 4.18 (s, 1H, CH2NH ), 5.08 (s, 2H, C4e
CH2), 6.38 (s, 1H, C3eH), 6.80e7.90 (m, 7H, Ar-H), 8.76
(s, 1H, NHCO); 13C NMR (75 MHz, CDCl3, d ppm):
161.08, 158.70, 156.18, 146.24, 136.78, 133.30, 132.16,
126.10, 123.24, 118.92, 116.24, 116.16, 114.40, 114.20,
108.40, 63.28; 19F NMR (470 MHz, CDCl3, d ppm):
ꢁ123.21 (s, 1F, C40eF); FAB-MS: m/z 303 (M þ H). Anal.
Calc. for C16H12FClN2O: C, 63.48; H, 4.00; N, 9.25; found:
C, 63.50; H, 3.97; N, 9.10%.
6.3.10. 8-Methyl-4-[(40-bromo) phenoxymethyl]-1-aza
coumarin (9d2)
Yield: 82%; colorless crystals (acetic aciꢁd)1; m.p. 238e
240 ꢀC; IR (KBr): 1672, 3429, 1122 cm
;
1H NMR
(300 MHz, CDCl3, d ppm): 2.48 (s, 3H, C8eCH3), 5.62 (s,
2H, C4eCH2), 6.76e7.90 (m, 8H, Ar-H), 11.72 (s, 1H,
NH); 13C NMR (75 MHz, CDCl3, d ppm): 160.40, 159.88,
157.12, 153.78, 134.79, 134.98, 127.04, 125.78, 121.54,
120.64, 116.40, 116.14, 112.52, 114.20, 108.80, 67.52,
16.50; FAB-MS: 345 (M þ H). Anal. Calc. for C17H14BrNO2:
C, 59.30; H, 4.06; N, 4.06; found: C, 59.20; H, 3.84; N, 3.70.
6.4.4. 8-Methyl-4-[(40-fluoro) anilinomethyl]-1-aza
coumarin (10d)
Yield: 82%; pale green crystals ꢁ(1acetic acid); m.p. 230e
232 ꢀC; IR (KBr): 1657, 3357 cm
;
1H NMR (300 MHz,
CDCl3, d ppm): 2.48 (s, 3H, C8eCH3), 3.72 (s, 1H, CH2NH ),
4.38 (s, 2H, C4eCH2), 6.59 (s, 1H, C3eH), 6.88e7.46 (m,
7H, Ar-H), 8.76 (s, 1H, NHCO); 13C NMR (75 MHz,
CDCl3, d ppm): 162.08, 158.80, 156.47, 144.38, 136.20,
133.14, 132.34, 126.17, 123.77, 118.78, 116.36, 116.28,
114.26, 114.18, 108.80, 63.44, 18.33; 19F NMR (470 MHz,
CDCl3, d ppm): ꢁ123.89 (s, 1F, C40eF); FAB-MS: m/z 283
(M þ H). Anal. Calc. for C17H15FN2O: C, 72.32; H, 5.36; N,
9.92; found: C, 71.94; H, 5.07; N, 9.70%.
6.4. General procedure for the preparation of
compounds 10aed
A mixture of substituted 4-bromomethylcarbostyril (8aed)
(4.0 mmol), 40-fluoro-aniline (4.0 mmol) in super dry xylene
(20 ml) was refluxed on oil bath for 10 h (135e148 ꢀC). After
the completion of the reaction, the separated solid was filtered,
washed with excess of cold ethanol, dried and crystallized
from suitable solvent.
Acknowledgments
6.4.1. 4-[(40-Fluoro) anilinomethyl]-1-aza coumarin (10a)
Yield: 68%; colorless crystals (acetic acid); m.p. 308e
The authors thank the National Dong Hwa University, Hua-
lien 974, Taiwan, for IR, NMR and FAB-MS data and the
Chairman and Principal of Krupanidhi College of Pharmacy
for providing facilities to conduct animal studies. One of the
authors Mr. Rajesh.G. Kalkhambkar is grateful to Karnatak
University and Karnatak Science College, Dharwad for the
University Research Studentship.
310 ꢀC; IR (KBr): 1659, 3363 cmꢁ1 1H NMR (300 MHz,
;
CDCl3, d ppm): 4.08 (s, 1H, CH2NH ), 4.60 (s, 2H, C4e
CH2), 6.59 (s, 1H, C3eH), 6.90e7.50 (m, 8H, Ar-H), 8.70
(s, 1H, NHCO); 13C NMR (75 MHz, CDCl3, d ppm):
160.43, 158.17, 156.70, 145.10, 136.22, 133.10, 132.60,
126.30, 123.66, 119.12, 116.71, 116.50, 114.30, 114.21,
109.88, 63.24; 19F NMR (470 MHz, CDCl3, d ppm):
ꢁ122.90 (s, 1F, C40eF); FAB-MS: m/z 269 (M þ H). Anal.
Calc. for C16H13FN2O: C, 71.63; H, 4.88; N, 5.22; found: C,
71.20; H, 4.48; N, 5.02%.
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