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Synthesis ofN-(Chlorophenyl)-2-hydroxynicotinanilides as

Potential Anti-inflammatory Agents

Chien-Ming Huanga,b

( ), Yong-Hong Hsieha

( ),

Wen-Hsin Huanga* ( ) and An-Rong Lee

a* ( )

aSchool of Pharmacy, National Defense Medical Center, Taipei 114, Taiwan, R.O.C.

bDivision of Pharmacy, Cheng-Hsin Rehabilitation Medical Center, Pei-Tou, Taipei 112, Taiwan, R.O.C.

(Received April 10, 2007; Accepted April 16, 2007)

ABSTRACT

Leflunomide 1 and its non-enzymically active metabolite, malononitrilamide (MNA, 2) are

clinical use for treating rheumatoid arthritis (RA). Study indicated that the active pharmaco-

phore, a-keto amide with the enolic hydroxyl group, was fully responsible for the immunosup-

pressive effects of malononitrilamide 2 leading a salicylamide derivative 3 developed. Previously,

we have conducted isosterically structural modification mainly based on salicylamide derivative 3,

which-hydroxy-enamide-containing portion remains untouched, to successfully synthesize a se-

ries ofN-(4-substituted phenyl)-2-hydroxynicotinanilides. After pharmacological screenings,

compounds bearing electron-withdrawing groups such as 4-Cl, 4-Br, and 4-NO2 significantly

showed potent anti-inflammatory activity.1 Currently, a series of compounds 5-14, which are the

chloro variants on phenyl moiety, mainly based on N-(substituted phenyl)-2-hydroxynicotin-

anilide 4-14 were further synthesized in high yields. After systematic pharmacological screenings

of compounds 4-14 and controls, compound 14 exhibited potent in-vivoanti-inflammatory activity

comparable to that of compound 5 and leflunomide 1, whereas the other compounds have compa-

rable activity to compound 4 and malononitrilamide 2 by both in vitro suppressing nitric oxide

(NO) production under the LPS-elicited macrophage Raw 264.7 cell and thein-vivocarrageenan-

induced paw edema assay, except for compounds 8 and 11.

Key words: Nicotinailides; Anti-inflammation; Leflunomide.

INTRODUCTION

Rheumatoid Arthritis (RA) is primarily one in-

flammatory disease of the most common diseases of

the elderly that causes pain, swelling, stiffness, and

loss of function in the debilitating joints often com-

plicated with a wide range of other symptoms such

as feeling tired, running a fever, or generally not

feeling well.2

RA treatments can help relieve pa-

tients pain, reduce swelling, slow down or stop joint

damage, increase ability to function, and improve

sense of well being. In addition to treatment with

conventional non-steroidal anti-inflammatory drugs

(NSAIDs), steroids, substantial advances in RA pa-

tients may include antirheumatic drugs, called dis-

ease-modifying antirheumatic drugs (DMARDs),

Taiwan Pharmaceutical Journal,2007,59, 39-46 39

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such as cyclosporine and methotrexate, which can

slow damage of the diseases. However, the signifi-

cant adverse effects of DMARDs have made themintolerable in practical use, resulting in frequent with-

drawal.3,4

The emergence of the de novo pyrimidine-nu-

cleotide biosynthetic pathway for lymphocyte acti-

vation and proliferation was thus recognized and

confirmed by the elucidation of the mechanism of

action of leflunomide 1,5 an immunosuppressive

agent, and which being non-enzymically converts to

a bioactive metabolite malononitrilamide (MNA) 2,

a-cyano--hydroxy-enamide, involves the inhibi-

tion of the de novo pyrimidine pathway acting at

dihydroorotate dehydrogenase (DHODH).

A study5 indicated that a -cyano--hydroxy-

enamide2, a-keto amide with the enolic hydroxyl

group fixed in a cis-configuration to the amide moi-

ety, is the active pharmacophore of leflunomide me-

tabolite fully responsible for the immunosuppres-

sive effects. Bertolini et al. proposed that aZ-form of

metabolite2, which exhibited an intra-molecularH-bonding stabilization based on molecular model-

ing techniques, has -cyano--hydroxy-enamide

moiety as novel rational pharmacophore of the ac-

tive metabolite of leflunomide.6

A lead compound3,7 a salicylamide derivative

which has the minimum structural and physico-

chemical feature, -hydroxy-enamide moiety, wassynthesized and exhibited immunosuppressive ac-

tivity superior to that of leflunomide.

In previous, we have conducted isosterically

structural modification mainly based on salicyl-

amide derivative 3, containing a -hydroxy-enamide

portion remains untouched, to successfully synthe-

size a series ofN-(4-substituted phenyl)-2-hydroxy-

nicotinanilides. Among them,N-phenyl-2-hydroxy-

nicotinanilide4 andN-(4-substituted phenyl)-2-hy-

droxynicotinanilides bearing electron-withdrawing

groups such as 4-Cl (5), 4-Br, and 4-NO2 signifi-

cantly showed potent anti-inflammatory activity,1

which follow Topliss rule for lead optimization.8,9

In this study, we further mainly focused on the

structural extensive modifications of chloro sub-

stituents on phenyl moiety ofN-phenyl-2-hydroxy-

nicotinanilide4 in order to search potent immuno-

modulating agents with fewer and lower adverse ef-

fects for potently ameliorating rheumatoid arthritisand other autoimmune diseases. A series of title

compounds, mono-, di- and tri-chloro substituents of

N-phenyl-2-hydroxynicotinanilides5-14, were eval-

uated anti-inflammatory activity by both in vitro

suppressing nitric oxide (NO) production under the

LPS-elicited macrophage Raw 264.7 cell and the

in-vivocarrageenan-induced paw edema assay.

RESULTS AND DISCUSSION

Chemistry

The N-(substituted phenyl)-2-hydroxynicotin-

anilides 4-14were prepared using 2-hydroxynico-

tinic acid as starting material treated with thionyl

chloride in the presence of dichloromethane for re-

fluxing over 3 h. The residue was then reacted with

the corresponding anilines in high yields (almost

80%) and recrystallization from butanol afforded the

40 Taiwan Pharm. J. Vol. 59, No. 1, 2007 Huanget al.

Fig. 1. Structure of leflunomide 1, malononitril-

amide 2, salicylamide derivative 3, 2-hy-

droxy-N-phenylnicotinamide 4, and 2-hy-

droxy-N-(4-chlorophenyl)-nicotinamide5.

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desired title compounds 4-14. The active intermedi-ate, 2-hydroxynicotinoyl chloride, was successfully

prepared by thermodynamically controlling the re-

action in the presence of dichloromethane media in-

stead of dioxane due to a dominant side product, 2-

chloronicotinyl chloride, formed as if the reaction

over 70 C.

Conformation of compounds 4-14 similar as

-cyano--hydroxy-enamide 2 could exhibit in a

manner of solvent-dependence, the (Z)-isomer isdominant due to marked stabilization by forming a

strong intra-molecular hydrogen bonding, which

was considered crucial in the contribution of biolog-

ical activity.6,7

Biological Evaluations

In a previous report,1 a series ofN-(4-substi-

tuted phenyl)-2-hydroxynicotinanilides, isosterically

structural modification mainly based on salicyl-

amide derivative 3, containing a -hydroxy-enamide

portion remains untouched, were successfully syn-

thesized by introduction of electron-withdrawing

substituents such as CF3, OCF3, F, Cl, Br, I, CN, and

NO2at the para postion in the phenyl moiety, which

show compounds bearing electron-withdrawing groups

such as 4-Cl, 4-Br, and 4-NO2significantly showed

potent anti-i nflammatory act ivity, and follow the

Topliss rule for lead optimization. The Topliss tree

for aromatic substitution assumes that the lead com-pound has been synthesized and cont ains a mono-

substituted aromatic ring. The analog that should be

synthesized after unsubstituted derivative is the 4-

chloro compound. The chloro substituent is more

electron-withdrawing and hydrophobic than the H

atom and therefore the and values are positive as

Hammetts quantitative correlation.

Moreover, a series of title compounds, N-(sub-

stituted phenyl)-2-hydroxynicotinanilides5-14bear-ing mono- di- and tri-chloro substituents on phenyl

moiety, were synthesized and evaluated anti-inflam-

matory activity by both in vitro suppressing nitric

oxide (NO) production under the LPS-elicited macro-

phage Raw 264.7 cell and the in-vivo carrageenan-

induced paw edema assay to investigate their struc-

ture-activity relationships. The anti-inflammatory

results, expressed as IC50 (M) for suppressing NO

production level to macrophages and percent inhibi-

tion of the response to carrageenan-induced inflam-

mation, are presented in Table 1.

Examination of these data indicated that activ-

ity is significant overall. None of compounds exhib-

ited more potent inhibition of NO production in LPS-

elicited macrophages than compound5 (4-Cl, IC50

2.38 0.20M) and compound4 (unsubstituent of

H at phenyl moiety, IC50 9.98 1.25M). The na-

ture of the substituents at the phenyl moiety of the ti-

Novel 2-Hydroxynicotinanilide Derivatives Taiwan Pharm. J. Vol. 59, No. 1, 2007 41

Scheme 1

Reagents and condition: (a) SOCl2/CH2Cl2, reflux 3 h; (b) respective aniline/dioxane, reflux 3 h.

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tle compounds does not seem to increase the activity

noticeably even those compounds are made by fol-

lowing the Topliss principle.

From thein-vivocarrageenan-induced paw ede-

ma study (Table 1), compounds 8 (2,3-(Cl)2 substi-

tuents) and 11 (2,6-(Cl)2 substituents) showed the

least anti-inflammatory activity, but compound 14

(2,4,6-(Cl)3 substituents) has a comparable activity

(89%, at 3 h, and 67%, at 5 h) to that of compound 5

(4-Cl substituent, 91%, at 3 h, and 65%, at 5 h) and

of leflunomide1(85%, at 3 h, and 57%, at 5 h), at an

intraperitoneal 20 mg/kg dose. The other compounds

have comparablein-vivoanti-inflammatory activity

to compounds 4 (unsubstituent of H, 66%, at 3 h, and

45%, at 5 h) and MNA 2 (73%, at 3 h, and 63%, at 5

h), at an intraperitoneal 20 mg/kg dose.

Most of compounds significantly show consis-

tent anti-inflammatory activity betweenin-vitrosup-

pressing nitric oxide (NO) production under the LPS-

elicited macrophage Raw 264.7 cell and the in-vivo

carrageenan-induced paw edema assay, whereas

compound14(2,4,6-(Cl)3substituents) was extraor-

dinary active in the screening model against carrage-

enan-induced inflammation but exhibited less active

inhibition of NO production in LPS-elicited macro-

phages. This ambiguous result might be compound

14 displayed a water-insoluble in in-vitro cellular

study.

CONCLUSION

We have conducted the extensive chloro sub-

stituents of structural modification mainly on the

phenyl ring derived from isosterically heteroatomic

display of a salicylamide derivative3, a lead of anti-

rheumatic drugs, while its -hydroxy-enamide-con-

taining portion remains untouched, to successfully

synthesize 2-hydroxynicotinamides 4-14. By virtue

of their potent anti-inflammatory activity, our syn-

thetic compounds might have potential to be em-

ployed as nove l anti-rheumatic anti-inflammatory

agents. Finally, the information gleaned from this


Table 1. Anti-inflammatory effects of 2-hydroxy-N-(substituted phenyl)-nicotinamides 4-14 and controls

Paw edema (mL) after carrageenan challengea

(percentage inhibition, %)*Experimental candidate R

3 h 5 h

NO

(M)

Control 1.93 0.23 2.32 0.19

Leflunomide (1) 0.29 0.10 (85) 1.00 0.15 (57) 129.90 2.21

MNA (2) 0.52 0.08 (73) 0.86 0.12 (63) 157.60 6.11

4 H 0.66 0.11 (66) 1.28 0.17 (45) 9.98 1.25

5 4-Cl 0.17 0.06 (91) 0.81 0.11 (65) 2.38 0.20

6 2-Cl 1.25 0.17 (35) 1.41 0.21 (39) 155.34 1.91

7 3-Cl 0.45 0.13 (77) 0.83 0.15 (64) 54.36 2.07

8 2,3-(Cl)2 1.89 0.25 (2)#

2.08 0.19 (10)#

222.09 1.91

9 2,4-(Cl)2 0.52 0.13 (73) 0.88 0.18 (62) 60.01 2.48

10 2,5-(Cl)2 0.89 0.11 (54) 1.03 0.12 (56) 86.68 2.98

11 2,6-(Cl)2 1.97 0.31 (-2)

#

2.13 0.25 (8)

#

314.62 3.5912 3,4-(Cl)2 0.95 0.14 (51) 1.29 0.11 (44) 94.23 1.56

13 3,5-(Cl)2 0.70 0.13 (64) 0.96 0.19 (59) 74.73 2.16

14 2,4,6-(Cl)3 0.22 0.16 (89) 0.76 0.13 (67) 261.41 3.45

aEach value represents the mean S.E.M. of 5 animals.

Statistically significant different from control as *p< 0.05; statistically significant different from positive controls

(leflunomide and MNA) as#p< 0.05.

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study could suggest ways to develop new drugs use-

ful in the treatment of inflammatory or immunologi-

cal disorders such as RA.

MATERIALS AND METHODS

Chemistry

Melting points were taken in open capillary

tubes on a Buchi-530 melting point apparatus and

are uncorrected. UV-vis spectra were recorded on a

Shimazu UV-160A UV-Visble recording spectro-

photometer. IR spectra were recorded on a Perkin-

Elmer FTIR 1610 series infrared spectrophotometer

in KBr discs. 1

H- and 13

C-NMR spectra were deter-

mined on a Varian Gemini-300 NMR instrument.

Chemical shifts () were reported in parts per mil-

lion (ppm) relative to tetramethylsilane (TMS) as an

internal standard, and coupling constants (J) were

given in hertz (Hz). Fast atom bombardment (FAB)

mass spectra were recorded using a Finnigan MAT

95S (GC/MS) mass spectrometer. All reactions were

routinely monitored by TLC on Merck F254 silicagel plates. Merck silica gel (70-230 mesh) was used

for chromatography. Elemental analyses for carbon,

hydrogen and nitrogen were performed in the Instru-

ment Center of the National Science Counsel at the

Nat ional Taiwan Uni versit y usi ng Perkin-Elmer

CHN-2400. All the solvents and reagents were ob-

tained from commercial sources and purified before

use if necessary.

General synthetic procedure of N-(substi-

tuted phenyl)-2-hydroxynicotinanilides 4-14

2-Hydroxynicotinic acid (1.27 g, 10 mmol) was

warmed with thionyl chloride (2 mL) in dichloro-

methane (60 mL) at 50 C for 3 h. The excess thionyl

chloride was removedin vacuo. The residue was di-

rectly reacted with substituted anilines (12 mmol) in

dioxane (30 mL) for 3 h. The reaction mixture was

purified from chromatography (hexane/e thyl ace-

tate). Recrystallization of desired products from

butanol afforded the title compounds 4-14.

2-Hydroxy-N-phenylnicotinamide (4) and 2-Hydroxy-N-(4-chlorophenyl)nicotinamide (5) were

synthesized according to our previous published.1

2-Hydroxy-N-(2-chlorophenyl)nicotinamide

(6)

2.04 g (82% yield); TLC Rf= 0.42 (hexane:ethyl

acetate = 1:4); mp 224-226 C. UV max (DMSO)

nm (log ): 340 (4.11). IR (KBr) cm-1

: 3321 (OH),

2940 (CH), 1683 (C=O), 1595 (C=C). EI-MS m /z

(%): 248 (M+, 20), 122 (100). 1H-NMR (DMSO):

6.58 (1H, t,J= 6.6 Hz, pyridyl H-5), 7.12 (1H, t,J=

7.9 Hz, phenyl H-4), 7.35 (1H, t,J= 7.9 Hz, phenyl

H-5), 7.52 (1H, d,J= 7.9 Hz, phenyl H-6), 7.84 (1H,

dd, J= 6.6, 2.1 Hz, pyridyl H-4), 8.49 (1H, dd,J=

6.6, 2.1 Hz, pyridyl H-6), 8.55 (1H, d, J= 7.9 Hz,

phenyl H-3), 12.56 (1H, s, NH), 12.73 (1H, s, OH).13

C-NMR (DMSO) : 108.2, 121.2, 123.3, 123.9,

126.0, 129.0, 130.7, 136.9, 141.9, 146.4, 163.3,

163.8. Anal. Calcd. for C12H9ClN2O2: C, 57.96; H,3.65; N, 11.27. Found: C, 58.06; H, 3.54; N, 11.33.

2-Hydroxy-N-(3-chlorophenyl)nicotinamide

(7)



nm (log): 338 (4.13). IR (KBr) cm-1: 3265 (OH),

2929 (CH), 1690 (C=O), 1585 (C=C). EI-MS m /z

(%): 248 (M+, 40), 122 (100). 1H-NMR (DMSO):

6.57 (1H, t,J= 7.1 Hz, pyridyl H-5), 7.16 (1H, t,J=

8.1 Hz, phenyl H-5), 7.37 (1H, d, J= 8.1 Hz, phenyl

H-4), 7.44 (1H, d,J= 8.1 Hz, phenyl H-6), 7.82 (1H,

dd,J= 7.1, 2.1 Hz, pyridyl H-4), 7.98 (1H, s, phenyl

H-2), 8.45 (1H, dd, J= 7.1, 2.1 Hz, pyridyl H-6),

12.32 (1H, s, NH), 12.79 (1H, s, OH). 13C-NMR

(DMSO) : 108.3, 119.6, 120.6, 121.1, 124.8, 131.9,

134.7, 141.2, 141.8, 146.2, 163.3, 163.9. Anal.

Calcd. for C12H9ClN 2O2: C, 57.96; H, 3.65; N,


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11.27. Found: C, 57.80; H, 3.76; N, 11.12.

2-Hydroxy-N-(2,3-dichlorophenyl)nicotin-amide (8)



nm (log ): 341 (4.08). IR (KBr) cm-1: 3205 (OH),

2865 (CH), 1697 (C=O), 1588 (C=C). EI-MS m /z

(%): 283 (M+

, 40), 122 (100). 1

H-NMR (DMSO):

6.58 (1H, t,J= 5.8 Hz, pyridyl H-5), 7.36~7.38 (2H,

m, phenyl H-4, 6), 7.84 (1H, d, J= 5.8 Hz, pyridyl

H-4), 8.47~8.55 (2H, m, phenyl H-5, pyridyl H-6),

12.31 (1H, s, NH), 12.75 (1H, s, OH). 13C-NMR

(DMSO) : 108.4, 120.9, 121.6, 126.3, 129.7, 131.9,

133.2, 138.9, 142.1, 146.6, 163.5, 163.8.Anal. Calcd.

for C12H8Cl2N2O2: C, 50.91; H, 2.85; N, 9.89. Found:

C, 50.96; H, 3.02; N, 9.79.

2-Hydroxy-N-(2,4-dichlorophenyl)nicotin-

amide (9)


acetate = 1:4); mp 366-368 C. UV max (DMSO)nm (log ): 340 (4.15). IR (KBr) cm

-1: 3201 (OH),

2918 (CH), 1683 (C=O), 1584 (C=C). EI-MS m /z

(%): 283 (M+, 35), 122 (100). 1H-NMR (DMSO):

6.58 (1H, t,J= 7.0 Hz, pyridyl H-5), 7.47~7.59 (2H,

m, phenyl H-5, 6), 7.84 (1H, d, J= 7.0 Hz, pyridyl

H-4), 8.46 (1H, d,J= 7.0 Hz, pyridyl H-6), 8.57 (1H,

s, phenyl H-3), 12.14 (1H, s, NH), 12.78 (1H, s, OH).13

C-NMR (DMSO) : 108.4, 120.8, 121.9, 122.6,

128.9, 132.1, 133.3, 138.7, 142.5, 146.4, 163.7, 163.9.

Anal. Calcd. for C12H8Cl2N2O2: C, 50.91; H, 2.85;

N, 9.89. Found: C, 50.81; H, 2.95; N, 9.86.


amide (10)



nm (log ): 341 (4.13). IR (KBr) cm-1

: 3310 (OH),

2953 (CH), 1697 (C=O), 1590 (C=C). EI-MS m /z

(%): 283 (M+, 20), 122 (100). 1H-NMR (DMSO):

6.59 (1H, t,J= 7.1 Hz, pyridyl H-5), 7.18 (1H, dd,J

= 8.5, 2.0 Hz, phenyl H-4), 7.55 (1H, d, J= 8.5 Hz,phenyl H-3), 7.86 (1H, d, J= 7.1 Hz, pyridyl H-4),

8.48 (1H, d,J= 7.1 Hz, pyridyl H-6), 8.67 (1H, d,J=

2.0 Hz phenyl H-6), 12.18 (1H, s, NH), 12.76 (1H, s,

OH). 13C-NMR (DMSO) : 108.3, 120.7, 122.3,

122.4, 125.5, 131.9, 133.3, 138.2, 142.2, 146.6, 163.7,

163.8.Anal. Calcd. for C12H8Cl2N2O2: C, 50.91; H,

2.85; N, 9.89. Found: C, 50.87; H, 2.95; N, 9.78.


amide (11)



nm (log): 333 (3.99), 294 (3.26), 262 (3.56). IR

(KBr) cm-1

: 3336 (OH), 2988 (CH), 1676 (C=O),

1615 (C=C). EI-MS m/z (%): 283 (M+

, 80), 122

(100). 1H-NMR (DMSO): 6.56 (1H, t,J= 7.0 Hz,

pyridyl H-5), 7.33 (1H, t, J= 8.1 Hz, phenyl H-4),

7.53~7.55 (2H, m, phenyl H-3, 5), 7.84 (1H, dd, J=

7.0, 2.0 Hz, pyridyl H-4), 8.43 (1H, dd, J= 7.0, 2.0Hz, pyridyl H-6), 11.73 (1H, s, NH), 12.79 (1H, s,

OH). 13

C-NMR (DMSO) : 108.1, 120.8, 129.8,

130.2, 134.2, 134.2, 141.9, 146.4, 163.0, 164.0.Anal.

Calcd. for C12H8Cl2N2O2: C, 50.91; H, 2.85; N, 9.89.

Found: C, 50.84; H, 2.93; N, 9.88.


amide (12)

2.31 g (82% yield); TLC Rf

= 0.27 (hexane:ethyl


nm (log): 340 (4.22). IR (KBr) cm-1

: 3302 (OH),

2943 (CH), 1682 (C=O), 1591 (C=C). EI-MS m /z

(%): 283 (M+, 25), 122 (100). 1H-NMR (DMSO):

6.58 (1H, t,J= 7.0 Hz, pyridyl H-5), 7.49~7.59 (2H,

m, phenyl H-5, 6), 7.82 (1H, dd, J= 7.0, 2.0 Hz,

pyridyl H-4), 8.14 (1H, s, phenyl H-2), 8.44 (1H, dd,

J= 7.0, 2.0 Hz, pyridyl H-6), 12.36 (1H, s, NH),

12.82 (1H, s, OH). 13

C-NMR (DMSO) : 108.3,


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120.9, 121.3, 122.3, 126.6, 132.2, 132.6, 139.8, 141.9,

146.2, 163.4, 163.9.Anal. Calcd. for C12H8Cl2N2O2:

C, 50.91; H, 2.85; N, 9.89. Found: C, 50.89; H, 3.01;N, 9.77.


amide (13)



nm (log ): 339 (4.21). IR (KBr) cm-1: 3423 (OH),

3073 (CH), 1681 (C=O), 1594 (C=C). EI-MS m /z

(%): 283 (M+

, 30), 122 (100). 1

H-NMR (DMSO):

6.58 (1H, t, J= 6.8 Hz, pyridyl H-5), 7.30 (1H, s,

phenyl H-4), 7.77~7.83 (2H, m, phenyl H-2, 6), 7.84

(1H, dd,J= 6.8, 2.1 Hz, pyridyl H-4), 8.44 (1H, dd,J

= 6.8, 2.1 Hz, pyridyl H-6), 12.40 (1H, s, NH), 12.82

(1H, s, OH). 13

C-NMR (DMSO) : 108.4, 119.4,

120.8, 124.3, 135.6, 142.1, 146.4, 163.6, 163.9.Anal.

Calcd. for C12H8Cl2N2O2: C, 50.91; H, 2.85; N, 9.89.

Found: C, 50.87; H, 2.94; N, 9.79.

2-Hydroxy-N-(2,4,6-trichlorophenyl)nicotin-amide (14)



nm (log ): 334 (4.01), 294 (3.35), 265 (3.64). IR

(KBr) cm-1

: 3416 (OH), 3075 (CH), 1698 (C=O),

1615 (C=C). EI-MS m/z (%): 317 (M+, 20), 122

(100). 1H-NMR (DMSO): 6.57 (1H, t,J= 6.9 Hz,

pyridyl H-5), 7.77 (2H, s, phenyl H-3, 5), 7.85 (1H,

d,J= 6.9 Hz, pyridyl H-4), 8.43 (1H, d, J= 6.9 Hz,

pyridyl H-6), 11.73 (1H, s, NH), 12.79 (1H, s, OH).13

C-NMR (DMSO) : 108.2, 120.5, 129.6, 133.4,

133.7, 135.1, 142.1, 146.5, 163.1, 163.9.Anal. Calcd.

for C12H7Cl3N2O2: C, 45.39; H, 2.22; N, 8.82.

Found: C, 45.36; H, 2.37; N, 8.67.

Pharmacology10

Cell culture

The mouse BALB/c macrophage cell line, RAW

264.7 (identical to ATCC number TIB-71), was ob-

tained from Bioresource Collection and Research

Center, Taiwan. The cells were maintained accord-ing to the reported method, being cultured in 50 cm2

plastic flasks (Nunc, Roskilde, Denmark) with the

medium renewed every 3 days.

Determination of cell viability by an MTT assay

To evaluate the cell viability, a methylthiazo-

letetrazolium bromide (MTT) assay was conducted

by the standard method as described previously. In-

cubation was performed after pretreating with a

combination of the polyhydroxyflavonoids, in con-

centrations of 25, 50, 100, and up to 200 M in

dimethyl sulfoxide, and LPS (100 ng/mL) in normal

saline for 24 h. Untreated cells were used as the con-

trol.

Nitrite quantification

The cells were cultured with or without a pre-

treatment by a polyhydroxyflavonoid of 25, 50, 100,

and up to 200M as already described. The produc-

tion of NO was determined by measuring the accu-

mulated level of nitrite in the culture supernatantwith the Griess reagent in LPS-stimulated macro-

phage cells. A quantity of 100 l of a sample aliquot

were mixed with 100l of the Griess reagent (0.1%

N-(1-naphthyl)ethylenediamine, 1% sulfanilamide,

and 2.5% phosphoric acid) in a 96-well plate and

then incubated at 25C for 10 min. The absorbance

at 550 nm was measured with an ELISA reader (MR

700, Dynatech Laboratories, Alexandria, VA, USA).

NaNO2was used as the standard to calculate the ni-

trite concentration.

Determination of anti-inflammatory activities by

the carrageenan-induced hind paw edema test on

rats

Male albino Wistar rats (180-215 g) were housed

and cared for under the guidelines of the Institu-

tional Animal Care and Use Committee at the Na-

tional Defense Medical Center, Taiwan. The rats

were assigned to groups, one of them being the con-


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trol. In order to induce inflammation, 50l of a 1%

carrageenan solution in normal saline was injected

into the right hind paw subplantar tissue, accordingto the modified method of Winter et al.11 The devel-

opment of paw edema was measured plethysmo-

graphically (Basile 7140 plethysmometer, Ugo,

Varese, Italy) and recorded prior to this administra-

tion. One hour before the carrageenan challenge, a

sample preparation (20 mg/kg) was injected i.p. into

a rat in a test group. Normal saline was injected in

the same way into animals in the control group. Af-

ter the carrageenan challenge, each paw volume

(mL) was measured hourly up to 5 h. The volumes of

the injected and of the contralateral paws were mea-

sured, using a plethysmometer (Ugo Basile, Italy), at

3 h after test compounds administered (i.e., 4 h after

induction of inflammation). The percentage of paw

edema and the inhibition of inflammation were cal-

culated by the previously reported protocol.

Statistical analysis

Each experimental data value is expressed as

the mean SEM. The statistical significance of dif-ferences was assessed with an analysis of variance

(ANOVA), followed by Tukeys test or Students

test between two groups. Differences with p values

of less than 0.05 are considered statistically signifi-

cant.

ACKNOWLEDGEMENTS

We gratefully acknowledge the research grant

supported from the Cheng-Hsin Rehabilitation Med-

ical Center (CHRMC 94-34), the Republic of China.

REFERENCES

1. Huang, C. M.; Hsieh, Y. H.; Huang, W. H.; Lee, A.

R. Synthesis of N-(4-substituted phenyl)-2-hy-

droxynicotinanilides as potential anti-inflamma-

tory agents. Chin. Pharm. J.2006,58, 105-113.

2. Schattenkirchner, M. The use of leflunomide in

the treatment of rheumatoid arthritis: an experi-

mental and clinical review. Immunopharmacol-

ogy 2000,47, 291-298.

3. van der Heide, A.; Jacobs, J. W.; Bijlsma, J. W. J.

The effectiveness of early treatment with sec-

ond-line antirheumatic drugs. A randomized,

controlled trial. Ann. Intern. Med. 1996, 124,

699-707.

4. El Desoky, E. S. Pharmacoatherapy of rheuma-

toid arthritis: an overview. Curr. Ther. Res.2001,

62, 92-112.

5. Silva, H. T.; Morris, R. E. Leflunomide andmalononitrilamides. Am. J. Med. Sci. 1997,313,

289-301.

6. Papageorgiou, C.; Zurini, M.; Weber, H.-P.;

Borere, X. Leflunomides bioactive metabolite

has the minimal structural requirements for the ef-

ficient inhibition of human dihydrooratate

dehydrogenase. Bioorg. Chem. 1997, 25, 233-

238.

7. Bertolini, G.; Aquino, M.; Biffi, M.; et al. A new

rational hypothesis for the pharmacophore of theactive metabolite of leflunomide, a potent immu-

nosuppressive drug. J. Med. Chem. 1997, 40,

2011-2016.

8. Topliss, J. G. Utilization of operational schemes

for analog synthesis in drug design. J. Med.

Chem.1972,15, 1006-1011.

9. Topliss, J. G. A manual method for applying the

Hansch approach to drug design. J. Med. Chem.

1977,20, 463-469.

10. Huang, W. H.; Lee, A. R.; Yang, C. L. Anti-

oxidative and anti-inflammatory activities of

polyhydroxyflavonoids ofScutellaria baicalensis

GEORGI. Biosci. Biotechnol. Biochem.2006,70,

2371-2380.

11. Winter, C. A.; Risley, E. A.; Nuss, C. W. Car-

rageenan-induced edema in hind paw of the rats as

an assay for anti-inflammatory drugs. Proc. Soc.

Exp. Biol. Med. 1962,111, 544-547.


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