INTRODUCTION:
The substituted derivatives of
N-phenylanthranilic acid are of practical interest as compounds with different
biological activities. The Ullmann reaction is used for their preparation. This
is based on the reaction of o-halobenzoic acids with arylamines in the presence
of potassium carbonate and copper powder as a catalyst. To increase the yield
of the N-phenylanthranilic acids, the reaction is sometimes carried out in
high-boiling solvents, such as nitrobutanol and DMF. Nitrobenzene and glycerine
have also been reported as solvent for this reaction.
It is known that the rate of the Ullmann
reaction1 in the synthesis of diarylamines is considerably
influenced by the nature of the solvent; substitution of the halogen bound to
the aromatic ring is considerably facilitated by using polar aprotic solvents,
such as DMF and DMSO; these solvents appreciably increase the nucleophilicity
of arylamines.
Now, if the substituted N-phenyl anthranilic acid so
obtained is treated with iodine monochloride (ICl), the iodine is expected to
get attached to the position-5 of the anthranilic acid moiety and then
5-iodo-N-(substituted) phenyl anthranilic acids will be obtained2,J-3.
Thus, anthanilic acid derivatives of the following
general structure were synthesized during the course of the present work3:
EXPERIMENTAL:
Materials and Methods:
Procedure for synthesis of substituted Sulfonamides
(1,2,3) : Acetanilide
(20g, 0.148 mol) and chlorosulphonic acid (50 ml, 0.77 mol) were refluxed for 1
hour on a water bath,then poured on the crushed ice and filtered. Precipitate of
p-acetamido benzene sulphonyl chloride (1) was obtained. A mixture
of Amine (-NR1R2) and water was added to the above
product and heated with occasional swirling to just below the boiling point for
about 15 minutes. It is then cooled in ice and added H2SO4,
precipitate of p-acetamidobenzene sulphonamide (2) was filtered and
washed with water. Above crude product was then hydrolysed with hydrochloric
acid and water to give final substituted sulfonamides (3).
Preparation of N-(4-substituted sulfonamidophenyl)
Anthranilic Acid (4, 5, 6):-
Vrrious substituted benzoic acids 1.6 g (i.e.
o-chlorobenzoic acid/ 2,4-dichlorobenzoic acid/ 2,chloro,4,nitrobenzoic acid),
substituted sulfonamide (3) 1.72 g, potassium carbonate 1.38 gm and
copper oxide 300 mg were mixed together and dissolved in DMF 5 ml. It was then
heated under reflux for 3 hours on an oil bath on 150-1600C. After 3
hours of refluxing this reaction mixture was filtered and treated with dil. HCl
poured on crushed ice. The solid (4,5,6) thus precipitated out was
collected, filtered and washed with plenty of waterJ-1.
Preparation of Iodine substituted-N-(4-substituted
sulfonamidophenyl) Anthranilic Acid (7):-
N-(4- substituted sulfonamidophenyl) Anthranilic Acid
(0.5g) (4,5,6,) was taken in a beaker and 25 ml of 12.5% HCl was
dissolved into it by continuous stirring on magnetic stirrer. A solution of 1.2
g iodine monochloride in 10 ml 25% HCl was added to the previous solution and
stirred for one minute; a yellow precipitate appeared. The reaction mixture was
diluted with 25 ml water and raised the temperature of well stirred mixture
gradually and maintained at 900C for 15 minutes. Allowed to cool at
room temperature, filtered and washed with water and dried. The compound was
purified by dissolving it in dil. NaOH solution and precipitated with dil.HClJ-4.
PHARMACOLOGICAL EVALUATION:
(Anti-inflammatory Activity)
Paw Edema Method:
Among the many methods used for the screening of
anti-inflammatory drugs Carrageenin induced paw
edema method is one of the most commonly employed techniques.
This method is based upon the ability of such agents to inhibit
the edema produced in the hind paw of the rat after injection of a phlogistic
agent. Many phlogistic agents (irritants) have been used, such as brewer’s
yeast, formaldehyde, dextran, egg albumin, kaolin, Aerosil, sulfated
polysaccharides like carrageenin or naphthoylheparamine. The effect can be
measured in several ways. Usually, the volume of the injected paw is measured
before and after application of the irritant and the paw volume of the treated5,6.
Method:-
The anti-inflammatory activities of
synthesized compounds were carried out by the Carrageenan Induced Paw edema method
of Winter et al., 1962. The albino rats (200-300 gm) were divided into seven
groups of six animals each. One group named as Control (Group-I), another was
Standard (Group-II) and remaining groups were used for test groups, named as
Test Group I, Test group II, Test group III, Test group IV and Test
group V. Rats were weighed and marked for identification. A mark was made on
left hind paw of each rat just beyond tibio-tarsal junction, so that every time
the paw could be dipped in the column up to the fixed mark to ensure constant
paw volume. The initial paw volume of each rat was noted by mercury
displacement method. The Group-I, serving as control, was administered 5%
acacia solution in a volume of 1 ml/100g, body weight, orally. Group-II,
serving as standard, was administered Indomethacin (10 mg/kg, body weight,
orally). Test group I, Test group II, Test group III. Test group IV
and Test group V serving as test was administered synthesized compounds in the
dose of 100 mg/kg body weight, orally7,8.
One hour after the oral administration of
control, standard and test drug, 0.1 ml of 1% Carrageenan in normal saline was
injected into the plantar aponeurosis of the left hind paw of each rat. The
volume of the paw was measured by a plethysmometer in 1, 2, 3 and 4 hour after
Carrageenan suspension injection. The percentage increase in paw
volume in animals treated with standard, synthesized compounds were compared
with the increase paw volume of animals of control group after 1, 2, 3 and 4
hour.
RESULT AND DISCUSSION:
The N-(Aryl) anthranilic acids are a well established
class of NSAIDS with several drugs which are marketed. The work done by the
various workers on N-(substituted) anthranilic acids suggests that these
possess diverse type of biological properties including anti-inflammatory,
analgesic, antipyretic, diuretic, antimicrobial, anticancer etc.
The antimicrobial, anti-inflammatory and analgesic
activity promoted us to synthesize some new N-(Substituted)anthranilic acids
which would include more effectiveness and specific activities9,10.
(Fig. 1)
Spectral Analysis :-
N1b.
IR (KBr) in cm-1 (Figure
5) :- 3500.2
(O-H stretching), 2927.6 (C-H stretching), 1696 (C=O stretching), 1549 (C=C
stretching), 672 (C-I stretching),1253(N-H stretching). 1HNMR
(300 MHz, CDCl3) δ in ppm (figure 6):-
δ 7.04 ( 1H, aromatic C-H), δ 8.00 (1H,
secondary N-H), δ 3.20 ( 2H, CH2)
N1c.
IR (KBr) in cm-1 (Figure
5) :- 3507.2
(O-H stretching), 2931.6 (C-H stretching), 1711 (C=O stretching), 1609 (C=C
stretching), 678.4 (C-I stretching),1203(N-H stretching).
1HNMR (300 MHz, CDCl3) δ in ppm (figure 6):-
δ 7.06 ( 1H, aromatic C-H), δ 8.20 (1H,
secondary N-H), δ 3.23 ( 2H, CH2)
N2b.
IR (KBr) in cm-1 (Figure
5) :- 3491.2
(O-H stretching), 2967.6 (C-H stretching), 1706 (C=O stretching), 1621 (C=C
stretching), 679 (C-I stretching),1297(N-H stretching).
1HNMR (300 MHz, CDCl3) δ in ppm (figure 6):-
δ 7.12 ( 1H, aromatic C-H), δ 8.06(1H,
secondary N-H), δ 3.04 ( 2H, CH2)
N2c.
IR (KBr) in cm-1 (Figure
5) :- 3512.2
(O-H stretching), 2920.6 (C-H stretching), 1696 (C=O stretching), 1574 (C=C
stretching), 679.6 (C-I stretching),1265.8(N-H stretching).
1HNMR (300 MHz, CDCl3) δ in ppm (figure 6):-
δ 7.82 ( 1H, aromatic C-H), δ 8.26(1H,
secondary N-H), δ 3.43 ( 2H, CH2)
Thus in the present work different N-(Substitute
phenyl) anthranilic acids were synthesized and tested for a general profile
of biological activity as anti-inflammatory. A series of N-(4-sulfonamidophenyl)
anthranilic acids were synthesized by reaction of various substituted
anthranilic acid with O-chlorobenzoic acid these were further substituted with
iodine with the help of iodine monochloride.
The results showed that the N (substituted) phenyl
anthranilic acid, N- (substituted sulfonamidophenyl) anthranilic acids,
5-iodo-N(substituted)phenylanthranilic acid, i.e. all the derivatives tested
showed a moderate spectrum of anti-inflammatory
Thus it is possible that substitution at position 2 of
the anthranilic acid by sulfonamidophenyl and modification on the sulfonamide
moiety by using various amines and substituting iodine on 5th
position may yield compounds of much improved activity.
ACKNOWLEDGEMENT:
I wish to acknowledge Sophasticated Analytical
nstumentation Facility Department of Centeral Drug Research Institute, Lucknow
for providing facility of I.R. and N.M.R. analysis of my samples.
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JOURNALS:
1. Varnavas A., Valenta V., Berti F., Lassiani
L., “Synthesis of N-terminal substituted anthranilic acid dimmer derivatives
for evaluation on CCK receptors”, FARMACO year 2007, vol.56, pp 555-564.
2. Ratheesh M.,Helen A.,
“Antiinflammatory activity of Ruta Graveolens Linn on carrageenan induced paw
edema in wistar male rats.” J.Biotech.,2007 vol.6(10): pp 1209-1211.
3. Veerachamy A.,Viswas Raja S., Gnanavel V.,
Veeran P, Muniyandi R.C., “Synthesis, Analgesic, Anti-inflammatory and
Antibacterial Activitie OF Some Novel 2-Phenyl-3-substituted Quinazolin-4(3H)
Ones”. Biol. Pharm. Bull, 2002,vol 25(11): pp 1432-1435.
4. Peter Werner feit et al synthesized
new anthranilic acid derivatives being mono or di –N-substituted, having the
ether or thio- ether group in the 4- position and an alkyl sulphonyl group and
they reported diureticand saluretic activity with these derivatives.