Synthesis and anticancer activities of new 3-allylthio-6-(mono or disubstituted)aminopyridazines

Article abstract of DOI:10.1007/s12272-010-0201-x

A new series of 3-allylthio-6-(mono or disubstituted) aminopyridazines was synthesized by reacting 3-allylthio-6-chloropyridazine with several amines to develop new anticancer agents. These new compounds showed antiproliferative activities against lung ca

Full text of DOI:10.1007/s12272-010-0201-x

Arch Pharm Res Vol 33, No 2, 189-196, 2010
DOI 10.1007/s12272-010-0201-x
Synthesis and Anticancer Activities of New 3-Allylthio-6-(mono or
disubstituted)aminopyridazines
Yong-Hoon Won1 and Myung-Sook Park2
2
1Pharmaceutical Research Institute, Kwang Dong Pharmaceutical Co., Ltd, Pyong-Taek 459-020, Korea and College of
Pharmacy, Duksung Women’s University, Seoul 132-714, Korea
(Received August 14, 2009/Revised November 30, 2009/Accepted December 3, 2009)
A new series of 3-allylthio-6-(mono or disubstituted) aminopyridazines was synthesized by
reacting 3-allylthio-6-chloropyridazine with several amines to develop new anticancer agents.
These new compounds showed antiproliferative activities against lung cancer (A549), hepato-
blastoma (Hep3b), prostate cancer (PC3), colon cancer (SW480) and cervical cancer (HeLa)
cells in MTT assays, and could be promising candidates for chemotherapy of carcinomas. Com-
pound
for inhibiting the growth of these cell lines. This suggests the potential anticancer activity of
compound
5 (3-allylthio-6-homopiperidinylaminopyridazine) showed higher potencies than 5-FU
5
.
Key words: Allylthiopyridazines, Substituted aminopyridazines, Anticancer activities, MTT
assay
INTRODUCTION
The allylthio group of allicin and other organosulfur
compounds that are isolated from garlic is considered
an important pharmacopore (Cavallito et al., 1944;
Block et al., 1986; Yamasaki et al., 1991; Agarwal,
1996), i.e., a key structural component of the mole-
cules that is responsible for their antitumor activities.
In previous studies, various 3-allylthio-6-alkoxypyri-
dazine derivatives (K-compounds) and 3-allylthio-6-
alkylthiopyridazine derivatives (thio-K-compounds)
were synthesized (Lee et al., 2001; Kwon, 2002a,
2002b) and their biological activities were tested
Fig. 1. Allicin and reported allylthiopyridazines
(Jung et al., 2001). K-Compounds and thio-K-com- Shin and Kwon, 2003).
pounds showed especially good hepatoprotective and The isosteric replacement of the oxygen (or sulfur) of
antitumor activities (Kwon and Moon K-compounds by a nitrogen atom yields the amino-
2005) (Fig. 1).
,
The pyridazine group is an important moiety pre- pyridazines (Fig. 1). We recently reported the syn-
sent in many drugs acting at various pharmacological thesis of heterocyclo(or aryl)alkylaminopyridazines
targets (Tisler and Stanovnik, 1984; Kleeman and through amination (Lee et al., 2009), and of allylthi-
Engel, 2001; Song et al., 2008). This moiety has been oheterocyclopyridazines (Park and Park, 2005, 2007).
combined with the allylthio group (Lee et al., 2003; The synthesis of allylthio heterocyclo(or aryl)alkyl-
aminopyridazines and their antitumor activities
against SK-Hep-1 human liver cancer cells were also
reported (Kwon and Lee, 2005; Lee et al., 2009). We
were then interested in synthesizing aminopyri-
dazines through coupling of pyridazinyl chloride with
Correspondence: Myung-Sook Park, College of Pharmacy, Duk-
sung Women's University, Seoul 132-714, Korea
Tel: 82-2-901-8395, Fax: 82-2-901-8386
E-mail: mspark@duksung.ac.kr
189

190
Y.H. Won and M.S. Park
Fig. 2. Derivatives of amino-K-compound
amines known to give new amino-K-compounds (Fig. 3-Allylthio-6-morpholinylaminopyridazine (3)
1
2). We also designed new 3-allylthio-6-aminopyrida- Yield: 8%, mp 116-117oC. H NMR (CDCl3)
δ 7.18 (s,
zine derivatives (mono or disubstituted aminopyri- 2H, pyridazine), 5.97-5.92 (m, 1H, =CH), 5.28 (d,
J
=
dazines)
3-12 using a modification of this method in 15.7 Hz, 1H, CH2=), 5.10 (d,
J
= 9.9 Hz, 1H, CH2=),
order to discover potential anti-tumor candidates. We 3.88 (d,
J
= 6.9 Hz, 2H, SCH2), 3.79 (t, J = 4.5 Hz, 4H,
tested the ability of these synthetic compounds to CH2×2), 2.81 (t,
J
= 4.5 Hz, 4H, CH2×2), 1.79 (s, 1H,
159.09, 153.03, 133.57, 128.95,
inhibit the growth of lung cancer (A549), hepatoblas- NH). 13C NMR (CDCl3)
δ
toma (Hep3b), prostate cancer (PC3), colon cancer 117.86, 114.22, 66.86, 56.59 (morpholine), 33.71. FT-
(SW480) and cervical cancer (HeLa) cell lines.
MATERIALS AND METHODS
Chemicals
IR (KBr cell) cm-1 3434, 3053, 2986, 1602, 1421, 1265.
3-Allylthio-6-piperidinylaminopyridazine (4)
Yield 13%, 1H NMR (CDCl3)
δ
7.06 (d,
= 9.5 Hz, 1H, aromatic), 6.03 (m,
= 16.9 Hz, 1H, CH2=), 5.08 (d,
and Tokyo Kasei. Melting points were determined in = 9.9 Hz, 1H, CH2=), 3.91 (d, = 6.9 Hz, 2H, SCH2),
open capillary tubes on a Büchi 535 melting point 3.58 (t, = 5.4 Hz, 4H, CH2×2), 1.66 (m, 6H, piperi-
apparatus and were uncorrected. NMR spectra were dine), 1.66 (s, 1H, NH). 13C NMR (CDCl3)
158.38,
J = 9.5 Hz, 1H,
aromatic), 6.82 (d,
J
Chemicals were supplied by Aldrich, Sigma, Merck, 1H, =CH), 5.30 (d,
J
J
J
J
δ
recorded using a Bruker 300 MHz NMR spectrometer. 150.03, 133.81, 127.82, 117.62, 113.75, 46.42, 33.51, 25.32,
Chemical shifts are reported in parts per million and 24.54. FT-IR (KBr cell) cm-1 3400, 3051, 2981, 2939,
were recorded in chloroform-d or dimethyl-d6 sulfoxide 1589, 1433, 1265.
with tetramethylsilane as the internal standard.
NMR spin multiplicities are indicated by the symbols: 3-Allylthio-6-homopiperidinylaminopyridazine (5)
s (singlet), d (doublet), t (triplet), q (quartet), and m Yield 11%, 1H NMR (CDCl3)
δ
7.06 (d,
= 9.5 Hz, 1H, aromatic), 6.01 (m,
= 16.8 Hz, 1H, CH2=), 5.09 (d,
= 7.0 Hz, 2H, SCH2),
= 5.9 Hz, 4H, CH2×2), 1.77 (m, 4H, CH2×2),
1.70 (s, 1H, NH), 1.56 (m, 4H, CH2×2). 13C NMR (CDCl3)
157.06, 148.53, 133.95, 128.08, 117.53, 111.89, 47.75,
J = 9.6 Hz, 1H,
(multiplet). IR spectra were recorded on a Perkin- aromatic), 6.68 (d,
Elmer 16F PC FT-IR spectrometer using NaCl discs 1H, =CH), 5.26 (d,
J
J
J
and pellets.
= 9.9 Hz, 1H, CH2=), 3.91 (d,
3.67 (t,
J
J
General synthetic procedure for the 3-allyl-
thio-6-heterocyclicaminopyridazines 3-7
δ
A solution of 3-allylthio-6-chloropyridazine
the appropriate amine (10 mmol) and ammonium 2985, 2932, 1592, 1429, 1265.
chloride (5 mmol) in -butanol (16 mL) was refluxed
2
(5 mmol), 33.72, 27.57, 27.02. FT-IR (KBr cell) cm-1 3434, 3053,
n
for 4-50 h. The solvent was evaporated under reduced 3-Allylthio-6-(4-methylpiperazinyl)aminopyri-
pressure. The residue was extracted with ethyl acetate dazine (6)
and dried over Na2SO4. After solvent evaporation, the Yield 28%, 1H NMR (CDCl3)
δ
7.11 (d,
= 9.6 Hz, 1H, aromatic), 6.01 (m,
= 17.1 Hz, 1H, CH2=), 5.11 (d,
J = 9.6 Hz, 1H,
residue was purified by column chromatography on aromatic), 6.83 (d,
silica gel. 1H, =CH), 5.28 (d,
J
J
J

Synthesis of 3-Allylthio-6-(mono or disubstituted)aminopyridazines
191
= 10.2 Hz, 1H, CH2=), 3.92 (d,
3.64 (t, = 5.1 Hz, 4H, CH2×2), 2.55 (t,
CH2×2), 2.36 (s, 3H, CH3), 2.17 (s, 1H, NH). 13C NMR aromatic), 7.27 (d,
(CDCl3) 158.21, 151.07, 133.64, 127.96, 117.69, = 7.1 Hz, 2H, aromatic), 6.89 (d,
113.75, 54.51, 46.09, 45.18, 33.41, 30.90. FT-IR (KBr aromatic), 6.49 (d, = 9.5 Hz, 1H, aromatic), 6.02 (m,
cell) cm-1 3400, 3053, 2985, 2944, 1592, 1431, 1265.
1H, =CH), 5.30 (d, = 15.6 Hz, 1H, CH2=), 5.12 (d,
= 10.0 Hz, 1H, CH2=), 4.02 (t, = 7.7 Hz, 2H, CH2),
3-Allylthio-6-(4-thiomorpholinyl)aminopyrida- 3.95 (d, = 6.9 Hz, 2H, SCH2), 1.72 (m, 2H, CH2), 0.92
= 7.4 Hz, 3H, CH3). 13C NMR (CDCl3)
157.49,
J
= 6.9 Hz, 2H, SCH2), 3-Allylthio-6-
= 5.4 Hz, 4H, Yield 29%. 1H NMR (CDCl3)
= 4.9 Hz, 1H, aromatic), 7.20 (d,
= 9.5 Hz, 1H,
N
-propylanilinopyridazine (10)
J
J
δ
7.40 (t, = 7.9 Hz, 2H,
J
J
δ
J
J
J
J
J
J
J
zine (7)
(t,
J
δ
Yield 12%, mp 116-117oC, 1H NMR (CDCl3)
δ 7.22 (d, 150.67, 144.33, 133.69, 130.12, 127.51, 126.56, 117.71,
J
= 9.5 Hz, 1H, aromatic), 6.94 (d,
aromatic), 6.00 (m, 1H, =CH), 5.32 (d,
CH2=), 5.15 (d, = 10.1 Hz, 1H, CH2=), 4.20 (t,
Hz, 4H, CH2×2), 3.94 (d, = 6.8 Hz, 2H, SCH2), 3.11 3-Allylthio-6-
(t,
= 5.4 Hz, 4H, CH2×2), 1.60 (s, 1H, NH). 13C NMR Yield 45%. 1H NMR (CDCl3)
(CDCl3)
J
J
= 9.5 Hz, 1H, 115.42, 52.36, 33.40, 20.53, 11.33. FT-IR (KBr cell) cm-1
= 15.5 Hz, 1H, 3434, 3053, 2985, 2933, 1587, 1421, 1265.
J
J = 5.3
J
N
-butylanilinopyridazine (11)
7.40 (t, = 7.9 Hz, 2H,
= 5.1 Hz, 1H, aromatic), 7.20 (d,
= 7.1 Hz, 2H, aromatic), 6.89 (d, = 9.5 Hz, 1H,
= 9.5 Hz, 1H, aromatic), 6.02 (m,
= 16.9 Hz, 1H, CH2=), 5.12 (d,
= 7.8 Hz, 2H, CH2),
= 6.9 Hz, 2H, SCH2), 1.66 (m, 2H, CH2), 1.36
(5 (m, 2H, CH2), 0.89 (t,
= 7.4 Hz, 3H, CH3). 13C NMR
-alkyl aniline (10 mmol) and ammonium (CDCl3) 157.51, 150.69, 144.35, 133.69, 130.12, 127.52,
J
δ
J
δ
155.84, 153.47, 133.08, 128.63, 118.22, 114.06, aromatic), 7.27 (d, J
50.78, 44.46, 33.22. FT-IR (KBr cell) cm-1 3421, 3082,
2980, 2922, 1586, 1447, 1279.
J
J
aromatic), 6.49 (d,
1H, =CH), 5.29 (d,
J
J
J
= 10.6 Hz, 1H, CH2=), 4.04 (t,
3.95 (d,
J
General synthetic procedure for the 3-allylthio-
J
6-
A solution of 3-allylthio-6-chloropyridazine
mmol), the
chloride (5 mmol) in
N-alkylanilinopyridazines 8-12
2
J
N
δ
n
-butanol (16 mL) was refluxed 126.56, 117.72, 115.42, 50.61, 33.45, 29.56, 20.22,
for 6-25 h. The solvent was evaporated under reduced 13.97. FT-IR (KBr cell) cm-1 3412, 3053, 2984, 2932,
pressure. The residue was extracted with ethyl acetate 1587, 1421, 1265.
and dried over Na2SO4. After solvent evaporation, the
residue was purified by column chromatography on 3-Allylthio-6-
silica gel.
N
-pentylanilinopyridazine (12)
Yield 40%. 1H NMR (CDCl3)
7.42 (t, = 7.8 Hz, 2H,
aromatic), 7.27 (d, = 4.8 Hz, 1H, aromatic), 7.20 (d,
= 7.2 Hz, 2H, aromatic), 6.89 (d, = 9.6 Hz, 1H,
= 7.9 Hz, 2H, aromatic), 6.49 (d, = 9.3 Hz, 1H, aromatic), 6.02 (m,
aromatic), 7.23 (m, 3H, aromatic), 6.92 (d, = 9.6 Hz, 1H, =CH), 5.29 (d, = 16.8 Hz, 1H, CH2=), 5.12 (d,
= 9.3 Hz, 1H, aromatic), 6.04 = 9.9 Hz, 1H, CH2=), 4.03 (t, = 7.8 Hz, 2H, CH2),
= 17.1 Hz, 1H, CH2=), 5.12 (d, 3.95 (d, = 6.9 Hz, 2H, SCH2), 1.67 (m, 2H, CH2), 1.31
= 6.9 Hz, 2H, (m, 4H, CH2×2), 0.86 (t,
= 7.2 Hz, 3H, CH3). 13C
SCH2), 3.57 (s, 3H, CH3). 13C NMR (CDCl3)
157.61, NMR (CDCl3) 157.50, 150.67, 144.34, 133.70, 130.12,
δ
J
J
3-Allylthio-6-
N
-methylanilinopyridazine (8)
J
J
Yield 64%. 1H NMR (CDCl3)
δ
7.42 (t,
J
J
J
J
J
1H, aromatic), 6.65 (d,
(m, 1H, =CH), 5.31 (d,
J
J
J
J
J
= 10.7 Hz, 1H, CH2=), 3.95 (d,
J
J
δ
δ
151.12, 145.61, 133.72, 130.05, 127.08, 126.35, 117.71, 127.51, 126.55, 117.71, 115.41, 50.77, 33.46, 29.14,
115.39, 38.96, 33.29. FT-IR (KBr cell) cm-1 3434, 3052, 27.14, 22.59, 14.09. FT-IR (KBr cell) cm-1 3429, 3053,
2984, 2924, 1587, 1444, 1265.
2985, 2931, 1587, 1421, 1265.
3-Allylthio-6-
Yield 67%. 1H NMR (CDCl3)
aromatic), 7.28 (d,
N
-ethylanilinopyridazine (9)
Materials and methods for bioassay
Cell lines and culture conditions. Lung cancer
δ
7.42 (t, = 7.6 Hz, 2H,
J
J
= 5.9 Hz, 1H, aromatic), 7.20 (d, (A549), hepatoblastoma (Hep3b), prostate cancer (PC3),
J
= 7.1 Hz, 2H, aromatic), 6.89 (d, = 9.5 Hz, 1H, colon cancer (SW480) and cervical cancer (HeLa) cells
J
aromatic), 6.50 (d,
1H, =CH), 5.30 (d,
J = 9.5 Hz, 1H, aromatic), 6.02 (m, were purchased from the Korean Cell Line Bank, and
J
= 15.5 Hz, 1H, CH2=), 5.12 (d,
J
were maintained at 37oC in a humidified atmosphere,
with 5% CO2, in Dulbecco’s modified Eagle medium
= 10.0 Hz, 1H, CH2=), 4.12 (m, 2H, CH2), 3.95 (d,
6.9 Hz, 2H, SCH2), 1.26 (t,
NMR (CDCl3) 157.15, 150.71, 144.03, 133.75, 130.13, bovine serum (FBS) and 1% penicillin-streptomycin
J
=
J
= 7.0 Hz, 3H, CH3). 13C (DMEM) (Gibco-BRL Inc.) supplemented with 5% fetal
δ
127.57, 127.22, 126.63, 117.69, 115.54, 45.48, 33.38, agent (Gibco-BRL Inc.).
30.95, 12.65. FT-IR (KBr cell) cm-1 3410, 3051, 2981,
1586, 1425, 1265.
MTT assay. Lung cancer (A549), hepatoblastoma
(Hep3b), prostate cancer (PC3), colon cancer (SW480)

192
Y.H. Won and M.S. Park
and cervical cancer (HeLa) cells (5
×
103 cells/well) aminopyridazines has not been reported until now.
cultured in 96-well-plates were treated with various We applied a general method of preparing aminopyri-
concentrations of the synthetic compounds (3-12) and dazines from pyridazinyl halides and amines (Wermuth
allowed to attach for 24 h. Control cells were treated et al., 1989; Contreras et al., 1999; Parrot et al., 1999a).
with dimethyl sulphoxide (DMSO) equal to the highest
percentage of solvent used in the experimental condi- aminopyridazines
A series of 3-allylthio-6-(mono or disubstituted)
12 was prepared by allylthiola-
3-
tions. 5-FU was used as a positive control. Briefly, tion and nucleophilic substitution. The allylthio group,
after 24 h treatment with the compound (62.5, 125, a pharmacologically active group, was introduced on
250 and 500 µg/mL), 2 mg/mL of 0.5% MTT (3-(4,5- one side of the pyridazine ring. The amines with he-
dimethylthiaxol-2-yl)-2,5-diphenyl tetrazolium bro- terocycle such as morpholine, piperidine, homopiperi-
mide) was added to the media and the cells were dine, 4-methylpiperazine and 4-thiomorpholine and
further incubated for 2 h. The supernatant (100
was replaced with the same volume of DMSO, and the position of 3-allylthio-6-chloropyridazine
absorbance was measured at 540 nm with a micro- The key intermediate in these preparations was 3-
ELISA reader (Molecular Devices). The percent of allylthio-6-chloropyridazine , which could be readily
cells surviving was defined as the relative absorbance obtained from the corresponding 3,6-dichloropyri-
µl) the
N
-alkylanilines were introduced into the para
-
2
(Scheme 1).
2
of treated versus untreated cells.
dazine
1
by reaction with allylmercaptan. Conden-
with
12
sation of the 3-allylthio-6-chloropyridazine
various amines gave the final target products
(Table I).
2
3-
RESULTS AND DISCUSSION
Activated aryl halides react well with amines to give
Here, we present the substitution reaction of 3-
by amines, which pro-
halide with an amine is not only important for the duced 3-allylthio-6-(mono or disubstituted) aminopyri-
synthesis of amines, but is also essential for the dazines 12. In Table I, we summarize the physical
preparation of pharmaceuticals. Many reports have properties and the reaction conditions for synthesizing
been published on the nucleophilic amination of aryl compounds 12
halides. Even though a synthetic pathway for 3- 3-Allylthio-6-chloropyridazine
aminopyridazines has been developed (Wermuth et final aminopyridazines 12 by nucleophilic aromatic
the corresponding arylamines. The reaction of an aryl allylthio-6-chloropyridazine
2
3-
3-
.
2
was converted to
3
-
al., 1987; Parrot et al., 1999b; Contreras et al., 2001), substitution with amines in the presence of ammo-
the synthesis of 3-allylthio-6-(mono or disubstituted) nium chloride (Scheme 1) as an acid catalyst. The
Scheme 1. Synthesis of 3-allylthio-6-(mono or disubstituted) aminopyridazines 3-12

Synthesis of 3-Allylthio-6-(mono or disubstituted)aminopyridazines
193
Table I. Reaction conditions for the synthesis of target compounds
3-12 and antiproliferative activity in each cell lines
(A549, Hep3b, PC3, SW480 and HeLa)
Molar Ratioc
Reag./Subs.
Antiproliferative
Activity (cells)
Comp
R1
R2
Time /ha
mp /oC
Yield b/%
3
4
5
6
7
8
9
10
11
12
morpholinyl
piperidinyl
homopiperidinyl
4-methylpiperazinyl
4-thiomorpholinyl
phenyl
H
H
H
H
H
50
4
4
50
16
6
25
25
25
25
116-117
oil
8
2
2
2
2
2
2
3
3
3
2
-
13
11
28
12
64
67
29
45
40
Hep3b, PC3, HeLa
A549, Hep3b, PC3, SW480, HeLa
oil
oil
SW480
116-117
oil
57-59
49-51
74-75
oil
-
methyl
ethyl
propyl
butyl
pentyl
Hep3b, HeLa
A549, Hep3b, HeLa
phenyl
phenyl
phenyl
phenyl
-
-
-
a All reactions were performed in
n
-butanol under reflux. b Yield referred to isolated product.
c Reag./Subs. is the ratio of reagent (alkylamine) to substrate (chloropyridazine
2).
amination reactions of 3-allylthio-6-chloropyridazine
with a range of amines are shown in Table I. The as a broad singlet signal. The alkyl (methyl, ethyl,
alkyl group at R2 position was increased in carbon propyl, butyl and pentyl) NMR peak of 12 appeared
length up to five: methyl, ethyl, propyl, butyl and at 1.56-2.36 ppm as splitting signal. The pyridazine
pentyl.
13C NMR peak appeared at 128, 133, 153, and 159
The nucleophilic displacement of chlorine in 3- ppm, and the allyl peak appeared at 33, 111-115, and
allylthio-6-chloropyridazine requires prolonged reac- 117-118 ppm. In the FT-IR spectra, the NH absorp-
tion time at the reflux temperature of
-butanol. A tion band appeared at 3400-3434 cm-1.
typical reaction consisted of a mixture of amine (10 Finally, we synthesized ten new 3-allylthio-6-(mono
mmol), 6-allylthio-3-chloropyridazine (5 mmol), and or disubstituted) aminopyridazine derivatives 12 in
ammonium chloride (5 mmol) in -butanol stirred order to discover potential anti-tumor candidates. Re-
under reflux for 4~50 h. The reaction was usually fluxing of 3-allylthio-6-chloropyridazines and the
carried out using 1:2 (or 1:3) equivalents of 3-allylthio- corresponding amines, such as heterocycloamines and
6-chloropyridazine: amine. -alkylanilines, for 4~50 h produced the target amino-
The mono-allylthiolation from 3,6-dichloropyrida- K-compounds.
zines to 3-allylthio-6-chloropyridazine produced In order to investigate the potential anti-cancer
2
The NH NMR peak of 3-7 appeared at 1.66-2.17 ppm
8-
2
n
3-
n
2
N
1
2
high yields. Reactions of dichloropyridazines with activity of the ten synthetic compounds, the growth-
allylmercaptan occurred in yields of more than 95%. inhibitory effect of the synthetic compounds was
We previously reported the synthesis of 3-allylthio-6- examined against lung cancer (A549), hepatoblastoma
chloropyridazine
Park, 2007). 3-Allylthio-6-chloropyridazine
ethylaniline were reacted in the presence of ammo- conducted on cells treated with various concentrations
nium chloride in -butanol to form the corresponding of the compounds. 5-Fluorouracil (5FU), which pro-
products in 67% yield (Table I, entry ). 4-Amino- duces partial responses in 10% to 20% of patients with
2
through allylthiolation (Park and (Hep3b), prostate cancer (PC3), colon cancer (SW480)
2
and and cervical cancer (HeLa) cells. MTT assays were
N-
n
9
morpholine, 1-aminopiperidine, 1-aminohomopiperi- metastatic colon carcinomas, upper gastrointestinal
dine, 1-amino-4-methylpiperidine and 4-aminothio- tract carcinomas, and breast carcinomas (Brunton et
morpholine were converted into the corresponding al., 2006), was used as a positive control. The IC50
aminopyridazine derivatives in lower yields (Table I, values for these compounds were not determined by
entries
The pyridazine NMR peak of
7.42 and 6.94-7.04 ppm, and the allyl peak appeared
at 3.88-4.12, 5.08-5.15, 5.26-5.32, and 5.92-6.04 ppm. cells at a high concentration (250
3
-
7
).
the concentration range used in this study.
Of the ten compounds tested, five compounds (4, 5,
3-
12 appeared at 6.49-
6,
8, and
9) inhibited the growth of lung cancer (A549)
µg/mL) (Fig. 3). We

194
Y.H. Won and M.S. Park
further investigated the antiproliferative activity of
Of the ten compounds tested, five compounds (
and 10) inhibited the growth of prostate cancer
growth than the other compounds. As shown in Fig. 3, (PC3) cells at a low concentration (62.5 g/mL) (Fig.
4, 5,
compound
4, which caused a greater inhibition of cell
8, 9
µ
this compound markedly inhibited A549 cell growth in 5). 5FU, a positive control, showed low inhibitory effects
a dose-dependent manner. The greatest inhibition was on the growth of PC3 cells at standard concentrations
observed with
higher potencies than 5FU in inhibiting the growth of against prostate cancer. We further investigated the
A549 cells, suggesting the potential anticancer activity antiproliferative activity of compounds and
5. Two compounds, 5 and 9, showed (62.5, 125, 250, 500 µg/mL). 5FU is not indicated
4, 5, 8, 9
of compounds
5
and
9.
10, which caused greater inhibition of cell growth
Of the ten compounds tested, five compounds (
4,
5,
than the other compounds. As shown in Fig. 5, these
8,
9
and 11) inhibited the growth of hepatoblastoma compounds markedly inhibited PC3 cell growth in a
(Hep3b) cells at a low concentration (62.5 g/mL) (Fig. dose-dependent manner. Two compounds ( and
4). We further investigated the antiproliferative acti- showed higher potencies than 5FU in inhibiting the
vity of compounds and 11, which caused growth of PC3 cells, suggesting the potential anti-
greater inhibition of cell growth than the other com- cancer activity of these compounds ( and ).
pounds. As shown in Fig. 4, compounds and 11 Of the ten compounds tested, five compounds (
markedly inhibited Hep3b cell growth in a dose- and ) inhibited the growth of colon cancer
dependent manner. Four compounds ( and (SW480) cells at a standard concentration (Fig. 6). We
showed higher potencies than 5FU in inhibiting the further investigated the antiproliferative activity of
growth of Hep3b cells, suggesting the potential anti- compounds and , which caused a greater inhibition
cancer activity of these compounds ( and ). of cell growth than the other compounds. As shown in
µ
4
5)
4, 5, 8, 9
4
5
4,
8,
9
4, 5,
6,
8
9
4,
5,
8
9)
4
5
4,
5,
8
9
Fig. 5. Anticancer activity of synthesized compounds (3-12)
in PC3 prostate cancer cells
Fig. 3. Anticancer activity of synthesized compounds (3-12)
in A549 lung cancer cells
Fig. 4. Anticancer activity of synthesized compounds (
in Hep3b hepatoblastoma cells
3
-
12
)
Fig. 6. Anticancer activity of synthesized compounds (3-12)
in SW480 colon cancer cells

Synthesis of 3-Allylthio-6-(mono or disubstituted)aminopyridazines
195
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