Synthesis and antitumor activity of novel pyrimidinyl pyrazole derivatives. II. Optimization of the phenylpiperazine moiety of 1-[5-methyl-1-(2-pyrimidinyl)-4-pyrazolyl]-3-phenylpiperazinyl-1-trans-propenes.

Article abstract of DOI:10.1248/cpb.50.453

A series of novel 3-substituted-1-[5-methyl-1-(2-pyrimidinyl)-4-pyrazolyl]-1-trans-propenes in order to improve the in vitro and in vivo activity of our prototype 3-[4-(3-chlorophenyl)-1-piperazinyl]-1-[5-methyl-1-(2-pyrimidinyl)-4-pyrazolyl]-1-trans-propene (2) were synthesized and evaluated by assays of growth inhibition against several tumor cell lines in vitro and antitumor activity against some tumor models when dosed both intraperitoneally and orally in vivo. Compounds 7a and 7e, the 3,5-difluorophenyl and 3,5-dichlorophenyl analogues of 2, respectively, showed significantly more potent cytotoxicity than 2 in vitro and potent antitumor activities without causing decrease of body temperature related to side effects.

Full text of DOI:10.1248/cpb.50.453

April 2002
Chem. Pharm. Bull. 50(4) 453—462 (2002)
453
Synthesis and Antitumor Activity of Novel Pyrimidinyl Pyrazole
Derivatives. II.1) Optimization of the Phenylpiperazine Moiety
of 1-[5-Methyl-1-(2-pyrimidinyl)-4-pyrazolyl]-3-
phenylpiperazinyl-1-trans-propenes
Hiroyuki NAITO,a Satoru OHSUKI,a Masamichi SUGIMORI,b Ryo ATSUMI,c Megumi MINAMI,d
e
d
d
d
,a
*
Yoshihide NAKAMURA, Mineko ISHII, Kenji HIROTANI, Eiji KUMAZAWA, and Akio EJIMA
Medicinal Chemistry Research Laboratory,a Discovery Research Laboratory,b Drug Metabolism & Physicochemical
Property Research Laboratory,c and New Product Research Laboratories III,d Daiichi Pharmaceutical Co., Ltd., 16–13,
Kita-kasai 1-chome, Edogawa-ku, Tokyo 134–8630, Japan, and Technical Department, Fuji Chemical Industries Co., Ltd.,e
530 Chokeiji, Takaoka, Toyama 933–0951, Japan. Received October 5, 2001; accepted January 17, 2002
A series of novel 3-substituted-1-[5-methyl-1-(2-pyrimidinyl)-4-pyrazolyl]-1-trans-propenes in order to im-
prove the in vitro and in vivo activity of our prototype 3-[4-(3-chlorophenyl)-1-piperazinyl]-1-[5-methyl-1-(2-
pyrimidinyl)-4-pyrazolyl]-1-trans-propene (2) were synthesized and evaluated by assays of growth inhibition
against several tumor cell lines in vitro and antitumor activity against some tumor models when dosed both in-
traperitoneally and orally in vivo. Compounds 7a and 7e, the 3,5-difluorophenyl and 3,5-dichlorophenyl ana-
logues of 2, respectively, showed significantly more potent cytotoxicity than 2 in vitro and potent antitumor activi-
ties without causing decrease of body temperature related to side effects.
Key words cytotoxic activity; antitumor activity; pyrazole; structure–activity relationship
In the previous paper,1) we reported the synthesis and anti-
shown in Chart 1. The new substituted piperazines 4a—d
were prepared from aniline derivatives 3a—d and bis(2-
chloroethyl)amine hydrochloride. Mannich reaction of 4-
acetyl-5-methyl-1-pyrimidinylpyrazole (5)1) with modified
piperazines 4a—d or 4e—i2) gave 6a—i, respectively. 1-
Propanone derivatives 6j—l were prepared according to the
reported procedure.3) Compounds 6a—l were reduced with
sodium borohydride to give the corresponding alcohols,
which were dehydrated by p-toluenesulfonic acid (p-TsOH)
to afford 1-trans-propene derivatives 7a—l. Catalytic hydro-
genation of 6i over Pd/C with acetic anhydride gave the 3-
acetylaminophenyl derivative 8. Compound 9 was obtained
from 8 by the same procedure as described for 7a—l from
6a—l. Carbamoylphenyl derivative 10 was prepared from 7c
by hydrolysis of the cyano group with hydrochloride.
We also developed a new, efficient synthetic method to
construct this scaffold by employing reductive amination in-
stead of Mannich reaction, because Mannich reaction of hy-
droxyphenylpiperazine 15 with 5 did not progress (Chart 2).
Bromination of 5 with Br2 and treatment with cesium acetate
(CsOAc) gave 11. Compound 11 was hydrolyzed with aque-
ous NaOH to give the a-hydroxyketone, followed by reduc-
tion with sodium borohydride, and then oxidative cleavage of
the 1,2-diol with sodium periodate to give the aldehyde 12.
According to the Mukaiyama protocol,4) the carbon–carbon
bond formation of 12 with allyl bromide was performed
using metallic tin, followed by protection of the secondary
alcohol with triethylsilyl chloride to give 13. Oxidation of 13
with osmium tetraoxide (OsO4), followed by oxidative cleav-
age of the 1,2-diol with sodium periodate gave the aldehyde
14. The above method demonstrated the synthesis of the key
intermediate 14 in 40% overall yield through 9 steps from 5.
The reductive amination of 15 with 14 by treatment with
NaBH3CN in acetic acid (AcOH)/EtOH gave the correspond-
ing adduct, followed by deprotection and simultaneous dehy-
dration with p-TsOH to afford the 1-trans-propene derivative
16.
tumor activity of novel pyrimidinyl pyrazole derivatives.
These derivatives were found as new antiproliferative agents
through random screening using our laboratory’s chemical li-
brary. One of them, 3-[4-(3-chlorophenyl)-1-piperazinyl]-1-
[5-methyl-1-(2-pyrimidinyl)-4-pyrazolyl]-1-trans-propene
(2), showed significant antitumor activity against several
tumor models by both intraperitoneal injection and oral ad-
ministration. Furthermore, 2 was free from the cross-resis-
tance to some currently used antitumor agents such as vin-
cristine (VCR) and adriamycin (ADM). These pyrazole de-
rivatives, however, tended to cause undesirable effects, e.g.,
muscle relaxation and decrease of body temperature without
body weight loss, because these compounds had previously
been prepared as tranquilizers or antihypertensive agents. To
overcome these problems, we have been seeking derivatives
of 1 that might furthermore increase the antitumor activity
while decreasing the side effects. As a first step in the struc-
tural modification of this scaffold, we focused on the
phenylpiperazine moiety, namely, the introduction of some
substituents on the phenyl ring and replacement of the
phenylpiperazinyl group with some piperidinyl groups. We
describe here the synthesis and structure–activity relation-
ships (SARs) with regard to in vitro cytotoxic activity and in
vivo antitumor activity of these pyrazole derivatives.
Chemistry
The synthesis of the derivatives bearing a substituted
phenylpiperazine moiety was carried out via the route
Fig. 1
To whom correspondence should be addressed. e-mail: naitoxns@daiichipharm.co.jp
© 2002 Pharmaceutical Society of Japan

454
Vol. 50, No. 4
Chart 3
Chart 1
treated with hydroxylamine to afford the imine, followed by
the rearrangement with polyphosphoric acid and reduction
with lithium aluminum hydride (LAH) to construct the 4-
phenylpiperidine skeleton 19b. Mannich reaction of 5 with
19a—f gave 20a—f. Compounds 20g—l were prepared ac-
cording to the reported procedure.3) 1-trans-Propene deriva-
tives 21a—l were obtained from 20a—l by the same proce-
dure as described in Chart 1.
Modification of the piperazine moiety was carried out via
the routes shown in Charts 4 and 5. Aminoethylation of 22
with 2-oxazolidinone as an aziridine equivalent7) afforded the
desired N-phenylethylenediamine (23). 2-Piperazinone 24
was prepared from 23 in two steps (2-chloropropanoyl chlo-
ride, Et3N, CH2Cl2, then K2CO3, tert-BuOH), and the following
reduction of the amide with LAH afforded 26a. Compound
26b was prepared via a palladium(II)-catalyzed aromatic am-
ination reaction with the unprotected 2-methylpiperazine.5)
Compounds 27a and 27b were obtained from 26a and 26b,
respectively, by the sequence of reactions described in Chart
2, because Mannich reaction with 5 did not progress (Chart
4).
The synthetic route to 31, which was not prepared from 29
by either Mannich reaction with 5 or reductive amination
with 14, is shown in Chart 5. The N-phenylethylenediamine
(23) was protected with benzyl chloroformate (ZCl), then
treated with 2-bromoacethyl bromide followed by construc-
tion of the piperazinone with K2CO3 to afford the protected
2-piperazinone 28. Deprotection of the Z group of 28 by hy-
Chart 2
Furthermore, some derivatives 21a—l with other varia-
tions as modifications of the piperazine or phenyl group were
synthesized via the route shown in Chart 3. Compound 19a
was prepared via a palladium(II)-catalyzed aromatic amina-
tion reaction5) with 1-bromo-3,5-difluorobenzene (17a) and
the unprotected 1,4-diazepane. 1-Bromo-3,5-dichloroben-
zene (17b) was converted to 18b through a palladium-cat-
alyzed cross-coupling reaction6) with 2-cyclopentene-1-one
in the presence of the phosphine ligand. Compound 18b was

April 2002
455
Table 1. Cytotoxic Activity of Pyrimidinyl Pyrazole Derivatives
GI50 (ng/ml)a)
Compd. No.
PC-6
PC-12
1
2
153
34
1020
208
7a
7b
7c
7d
7e
7f
7g
7h
7i
7j
7k
7l
9
6.4
57
36
63
376
139
568
205
45
574
951
411
16
67
52
113
6.3
7.8
117
175
48
2.6
14
6.9
Chart 4
Ͼ1000
Ͼ1000
41
Ͼ1000
Ͼ1000
240
10
16
21a
21b
21c
21d
21e
21f
21g
21h
21i
21j
21k
21l
27a
27b
31
VCR
5-FU
Ͼ1000
527
Ͼ1000
Ͼ1000
Ͼ1000
Ͼ1000
Ͼ1000
Ͼ1000
Ͼ1000
Ͼ1000
Ͼ1000
Ͼ1000
Ͼ1000
Ͼ1000
358
Ͼ1000
Ͼ1000
Ͼ1000
Ͼ1000
869
Ͼ1000
201
Ͼ1000
Ͼ1000
Ͼ1000
23
23
Ͼ1000
104
Ͼ1000
33
Chart 5
0.3
460
30
drogenation over Pd/C provided 29. The aldehyde 14 was re-
duced with NaBH4 to give the corresponding primary alco-
hol, which was tosylated to afford the deprotected compound
30. Alkylation of 29 with 30 by treatment with K2CO3 in
MeCN gave the corresponding adduct, followed by dehydra-
tion with p-TsOH to afford the 1-trans-propene derivative 31.
PC-6, PC-12: Human non-small cell lung cancer cell lines. a) See Experimental.
of a bulky group to the 3 position of the phenyl ring caused a
decrease of cytotoxic activity (9, 10). Strong cytotoxic activ-
ity was observed when the phenyl ring possessed a halogen
atom at the 3 position. The order of in vitro potency was
halogen atomϾhydroxy groupϾalkyl group. In the series of
compounds 21a—l in Chart 3, only 21i bearing the tetrahy-
dropyridinyl group showed almost the same activity as the
non-substituted phenylpiperazine 1 against PC-6. The other
compounds showed very weak or no activity. Introduction of
a methyl group to the piperazine caused a decrease of cyto-
toxic activity (27a, b), and the piperazinone derivative 31
was not active. The phenylpiperazine moiety in this scaffold
was considered to be essential for cytotoxic activity.
Compounds 7a, e, f, j, k, and l, which showed strong cyto-
toxic activity in vitro, were evaluated in the in vivo assay by
employing murine fibrosarcoma Meth A as a solid tumor
model. 5-FU was used as the reference compound. As shown
in Table 2, compounds 7a, e, j—l showed significantly potent
antitumor activity by intraperitoneal injection compared to
that of 5-FU. Among them, compounds 7a and 7e did not
cause muscle relaxation or decrease of body temperature
though these side effects were observed in prototypes 1 and 2
at the level of each maximum tolerated dose (MTD) in spite
of same antitumor activity. Introduction of fluorine or chlo-
rine atom at the 3 and 5 positions of benzene caused a de-
Biological Activity and Discussion
The in vitro cytotoxic activity of these compounds was
measured by using the human lung cancer cell lines PC-6
and PC-12, and the concentrations producing a 50% growth
inhibitory effect (GI50) are listed in Table 1. Compounds 1, 2,
and 5-fluorouracil (5-FU) were used as reference com-
pounds, because 1 and 2 are orally available and the adminis-
tration route is the same as that of 5-FU. Among a series of
phenylpiperazinyl derivatives, 7a, e, f, j, and l having a fluo-
rine or chlorine atom at the 3 or 5 position of benzene
showed the highest in vitro cytotoxic activity, while the cor-
responding compounds 7b with a bromine atom at the 3 po-
sition and 7d with fluorine atoms at other positions of ben-
zene showed moderate or weak activity. The activity of the
corresponding compounds 7c, g—i bearing CN, Me, CF3,
and NO2 at the same position of the phenyl ring was moder-
ate or weak. The hydroxy derivative 16 increased the activity
compared to that of the non-substituted compound 1. The ac-
tivity of the 3-methylphenyl compound 7g and the 3-trifluo-
romethylphenyl compound 7h was the same as that of the
non-substituted phenylpiperazinyl derivative 1. Introduction

456
Vol. 50, No. 4
Table 2. Antitumor Activity of Pyrimidinyl Pyrazole Derivatives against Murine Fibrosarcoma Meth Aa)
Antitumor Activityb)
i.p.
p.o.
Compd. No.
Dose
(mg/kg)
IR
(%)
BWLmaxc)
(%)
Dose
(mg/kg)
IR
(%)
BWLmax
(%)
D/Ud)
D/U
7a
7e
7.4ϫ5
5.1ϫ5
63***
31**
56***
31**
60***
24*
Ͻ0
Ͻ0
14.1
5.6
10.9
Ͻ0
7.4
Ͻ0
1.6
4.1
0/7
0/7
0/7
0/7
2/7
0/7
0/7
0/7
0/7
0/7
0/7
0/7
6/7
0/7
12.5ϫ5
10.5ϫ5
140.0ϫ5
98.0ϫ5
86***
82***
81***
77***
7.5
2.4
10.1
10.3
0/7
0/7
0/7
0/7
80.0ϫ5
60.0ϫ5
28.0ϫ5
19.6ϫ5
5.8ϫ5
7f
7j
52***
31
4.6ϫ5
7k
7l
38.4ϫ5
30.7ϫ5
210.0ϫ5
147.0ϫ5
40.0ϫ5
20.0ϫ5
57***
40***
71***
37***
66
6.8
1.1
27.0
9.2
5-FU
60.0ϫ5
40.0ϫ5
80
40**
25.4
14.5
3/7
0/7
26
IR and BWLmax of VCR were 9.0% and 17.3% (1.6 mg/kg, i.v.), respectively. IRs of 2 were 62% (43ϫ5 mg/kg, i.p.) and 88% (60ϫ5 mg/kg, p.o.).1) a) Murine fibrosarcoma
Meth A cells (1ϫ106 cells/0.1 ml/head) were implanted into the right flank of BALB/C mice (day 0). Pyrimidinylpyrazole derivatives at the indicated doses were administered in-
traperitoneally (i.p.) or per os (oral) administration (p.o.) on days 7—11 consecutively. b) See Experimental. c) Rate of body weight loss. d) Number of mice that died of
toxicity/number of mice used. *** pϽ0.001, ** pϽ0.01, * pϽ0.05 vs. the control group.
Fig. 2. Tumor Growth Inhibition Curves of 7a and 5-FU
*** pϽ0.001, ** pϽ0.01 vs. the control group.
method.6) As a result, compound 7a displayed quite a high
crease of side effects. When administered orally, compounds
7a and 7e exhibited a potent effect with respective inhibition
rate (IR) values of 86% and 81% at the MTDs, while 5-FU
and VCR showed weak activity with IR values of 40% and
9.0% at the MTDs. The tumor growth inhibition curves of 7a
and 5-FU are shown in Fig. 2. Furthermore, compounds 7a
and 7e were tested in the in vivo assay against murine P388
leukemia by intraperitoneal injection or oral administration.
As shown in Table 3, the antitumor activity of 7a and 7e by
oral administration was the same as that of 2 and superior to
that of 5-FU, although the effect of 7e was moderate when
administered intraperitoneally. The optimal dose of 7e was
about 10 times higher than that of 7a, even though these
compounds exhibited almost the same cytotoxic activity in
vitro. Therefore, the oral absorption rate of these two com-
pounds in rats was evaluated using the intestinal loop
absorption rate of 87.2%, while that of 7e was 6.2%. It is in-
teresting to note that only difference between a fluoride atom
and chloride atom on the phenyl ring dramatically affected
the oral absorbability.
Compounds 7a and 7e were selected for further evaluation
against several multi-drug resistant (MDR) cell lines, PC-
6/VCR and PC-6/ADM. These two cell lines have been re-
ported to overexpress P-glycoprotein.7) As shown in Table 4,
VCR and ADM showed high cross resistance rates of 400
against PC-6/VCR and 22 against PC-6/ADM, respectively.
Compounds 7a and 7e did not show cross-resistance as indi-
cated by their equal rates of 0.9 against PC-6/VCR and 1.3
against PC-6/ADM.
In conclusion, the study on structural modifications of the
phenylpiperazine moiety in this scaffold 1 has resulted in the

April 2002
457
Table 3. Therapeutic Effect of 7a and 7e on Mice Bearing P388 Murine Leukemiaa)
Survivalb)
Compd. No.
i.p.
p.o.
ILS (%)
Dose (mg/kg)
ILS (%)c)
D/Ud)
Dose (mg/kg)
D/U
7a
7e
NT
NT
48**
33**
74**
61**
10ϫ5
7ϫ5
160ϫ5
140ϫ5
60ϫ5
135**
93**
120**
118**
52**
0/6
0/6
0/6
0/6
0/6
200ϫ2
100ϫ2
100ϫ2
50ϫ2
0/6
0/6
0/6
0/6
5-FU
ILSs of 2 were 69% (77ϫ2 mg/kg, i.p.) and 127% (60ϫ5 mg/kg, p.o.). a) P388 tumor cells (1ϫ106) were inoculated into CDF1 mice i.p. (day 0). Pyrimidinylpyrazole deriv-
atives at the indicated doses were administrated i.p. on days 1 and 5 or p.o. on days 1—5, respectively. b) See Experimental. c) Increase in lifespane. d) Number of mice that
died of toxicity/number of mice used. NT: Not tested. ** pϽ0.01 vs. the control group.
Table 4. In Vitro Cytotoxicity against Multi-Drug Resistant Cell Linesa)
Jϭ8 Hz), 7.03 (1H, t, Jϭ2 Hz), 6.95 (1H, ddd, Jϭ8, 2, 1 Hz), 6.83 (1H, dd,
Jϭ8, 2 Hz), 3.3—3.1 (4H, m), 3.1—2.9 (4H, m).
1
GI50 ng/ml (Rateb))
PC-6/VCR
4c: Yield 37%, a white powder. H-NMR (CDCl3) d: 7.32 (1H, dd, Jϭ9,
7 Hz), 7.2—7.0 (3H, m), 3.3—3.1 (4H, m), 3.1—2.9 (4H, m).
Compd. No.
1
4d: Yield 10%, a white powder. H-NMR (CDCl3) d: 7.2—7.1 (1H, m),
PC-6
PC-6/ADM
6.96 (2H, t, Jϭ9 Hz), 3.4—3.5 (4H, m), 3.4—3.3 (4H, m).
3-[4-(3,5-Difluorophenyl)-1-piperazinyl]-1-[5-methyl-1-(2-pyrimidinyl)-
4-1H-pyrazolyl]-1-propanone (6a) Paraformaldehyde (650 mg, 22 mmol)
and a solution of 1 N HCl/EtOH (5.0 ml) were added to a mixture of 4a
(1.1 g, 5.0 mmol) and 51) (1.0 g, 5.0 mmol) in EtOH (85 ml), and the mixture
was heated to reflux for 4 d. The mixture was diluted with CHCl3, succes-
sively washed with saturated aqueous NaHCO3 and brine, and then dried.
Evaporation of the solvents afforded the crude mixture, which was chro-
matographed on a silica gel column (CHCl3/MeOHϭ50/1) to give 6a
(129 mg, 6%) as a yellow caramel. Compounds 4b—i were treated in the
same manner as described above to give 6b—i, respectively. The physical
data for these compounds and yields are shown in Table 5.
7a
7e
VCR
ADM
6.4
6.3
0.3
14
5.8
5.7
120
(0.9)
(0.9)
(400)
8.3
8.1
(1.3)
(1.3)
—
—
308
(22)
a) See Experimental. b) (GI50 value against VCR or ADM-resistant cell
line)/(GI50 value against PC-6 cell line).
discovery of 3,5-difluorophenyl and 3,5-dichlorophenyl com-
pounds, 7a and 7e, that displayed potent antitumor activity in
mice without causing a decrease of body temperature, com-
pared with that caused by 2, on both intraperitoneal injection
and oral administration. Furthermore, although the leading
compound 2 in this scaffold caused muscle relaxation and
crouching at MTD in mice, these visible symptoms were not
observed for compound 7a. Mechanism of action for the cy-
totoxic activity of this scaffold was reported to be inhibition
of tubulin polymerization.8) Further work with 7a to investi-
gate the inhibitory activity and the binding site on tubulin
will be described elsewhere.
3-[4-(3,5-Difluorophenyl)-1-piperazinyl]-1-[5-methyl-1-(2-pyrim-
idinyl)-4-1H-pyrazolyl]-1-trans-propene Hydrochloride (7a) Sodium
borohydride (50 mg, 1.3 mmol) was added in small portions to a solution of
6a (103 mg, 0.25 mmol) in anhydrous EtOH (10 ml) and THF (10 ml) at
0 °C, and the reaction mixture was stirred at room temperature for 2 h. The
reaction mixture was quenched with a solution of 1 N HCl/EtOH. The mix-
ture was diluted with CHCl3, successively washed with saturated aqueous
NaHCO3 and brine, and dried. Evaporation of the solvents afforded the cor-
responding secondary alcohol. Next, p-TsOH·H2O (68 mg, 0.38 mmol) was
added to a solution of the above product in anhydrous 1,4-dioxane (10 ml)
and THF (10 ml), and the mixture was heated to reflux for 40 min. The
reaction mixture was diluted with CHCl3, successively washed with satu-
rated aqueous NaHCO3 and brine, and dried. After removal of the solvents,
the crude mixture was chromatographed on a silica gel column (CHCl3/
MeOHϭ50/1) to afford the propene. An appropriate volume of a solution of
1 N HCl/EtOH was added to a solution of the propene in a small amount of
EtOH, and the solvent was removed. The residue was recrystallized from
EtOH to give 7a (39 mg, 35%) as a white powder. Compounds 6b—l were
treated in the same manner as described above to give 7b—l, respectively.
The physical data for these compounds and yields are shown in Table 6.
3-[4-(3-Acetylamino)-1-piperazinyl]-1-[5-methyl-1-(2-pyrimidinyl)-4-
1H-pyrazolyl]-1-propanone (8) Compound 6i (404 mg, 1.0 mmol) and
acetic anhydride (113 ml) were dissolved in AcOH (22 ml) and hydrogenated
over 10% Pd/C (110 mg) for 24 h at room temperature. The reaction mixture
was filtered through a Celite pad, and the filtrate was evaporated to afford the
crude mixture, which was chromatographed on a silica gel column (CHCl3/
MeOHϭ100/3) to give 8 (277 mg, 63%) as a yellow caramel. The physical
data for 8 are shown in Table 5.
Experimental
Melting points were determined on a Yanaco MP-500D apparatus and are
uncorrected. Infrared (IR) spectra were recorded on a JEOL JIR-5300 or
Horiba FT-720 spectrometer. 1H-NMR spectra were recorded on a JEOL
JNM-EX400 (400 MHz) instrument, and the chemical shifts are given in d
values. Mass spectra (MS) were recorded on a JEOL JMS-HX110 or a JMS-
AX505W mass spectrometer. Elemental analyses were performed with a
Perkin-Elmer Series II CHNS/O 2400 instrument. Column chromatography
was performed with silica gel 60 F 254 (70—230 mesh) (Merck). Sodium
sulfate was employed as a drying agent.
1-(3,5-Difluorophenyl)piperazine Hydrochloride (4a) A mixture of
3,5-difluoroaniline (3a) (10 g, 77 mmol) and bis(2-chloroethyl)amine hy-
drochloride (13.7 g, 77 mmol) in n-BuOH (120 ml) was refluxed for 48 h.
Anhydrous sodium carbonate (10.6 g, 77 mmol) was added to the mixture.
After being stirred for 24 h, the reaction mixture was cooled, and the precipi-
tate obtained was filtered. The precipitate was suspended with water and ex-
tracted with CHCl3. The organic phase was washed with water, dried, and
evaporated in vacuo. Et2O and 1 N HCl/EtOH (2.5 ml) were added to the
residue, and the precipitate obtained was filtered to give 4a (12.6 g) as a
white powder. Compounds 3b—d were treated in the same manner as de-
scribed above to give 4b—d, respectively.
3-[4-(3-Acetylamino)-1-piperazinyl]-1-[5-methyl-1-(2-pyrimidinyl)-4-
1H-pyrazolyl]-1-trans-propene Hydrochloride (9) Synthesis of 9 was
performed as described for the synthesis of 7a. Compound 9 was obtained
from 8 in 53% yield as a white powder. The physical data for 9 are shown in
Table 6.
3-[4-(3-Carbamoylphenyl)-1-piperazinyl]-1-[5-methyl-1-(2-pyrim-
idinyl)-4-1H-pyrazolyl]-1-trans-propene Hydrochloride (10) Compound
7c (88 mg, 0.2 mmol) was dissolved in conc. HCl (0.5 ml), and the mixture
was stirred for 62 h at room temperature. The reaction mixture was diluted
4a: Yield 74%, a white powder. 1H-NMR (DMSO-d6) d: 6.70 (1H, d,
Jϭ9 Hz), 6.56 (2H, t, Jϭ9 Hz), 3.5—3.4 (4H, m), 3.2—3.1 (4H, m).
4b: Yield 72%, a white powder. 1H-NMR (CDCl3) d: 7.10 (1H, t,

458
Vol. 50, No. 4
Table 5. Physical Data for Propanone Derivatives
Compd. No.
Yield (%)
1H-NMR (CDCl3) d
6a
6b
6
9.01 (2H, d, Jϭ5 Hz), 8.42 (1H, s), 7.67 (1H, t, Jϭ5 Hz), 6.77 (2H, d, Jϭ10 Hz), 6.58 (1H, t, Jϭ9 Hz), 4.0—3.9 (2H, m),
3.7—3.6 (2H, m), 3.5—3.4 (4H, m), 3.2—3.1 (4H, m), 2.82 (3H, s)
8.86 (2H, d, Jϭ5 Hz), 8.15 (1H, s), 7.35 (1H, t, Jϭ5 Hz), 7.10 (1H, t, Jϭ8 Hz), 7.03 (1H, t, Jϭ2 Hz), 6.95 (1H, ddd, Jϭ8,
2, 1 Hz), 6.83 (1H, dd, Jϭ8, 2 Hz), 3.21 (4H, t, Jϭ5 Hz), 3.09 (2H, t, Jϭ7 Hz), 3.00 (3H, s), 2.88 (2H, t, Jϭ7 Hz), 2.67
(4H, t, Jϭ5 Hz)
40
6c
6d
6e
6f
39
57
61
16
31
9.01 (2H, d, Jϭ5 Hz), 8.43 (1H, s), 7.66 (1H, t, Jϭ5 Hz), 7.47 (1H, d, Jϭ2 Hz), 7.45 (1H, t, Jϭ8 Hz), 7.37 (1H, dd, Jϭ8,
2 Hz), 7.26 (1H, d, Jϭ8 Hz), 4.0—3.9 (2H, m), 3.7—3.6 (2H, m), 3.4—3.4 (4H, m), 3.3—3.1 (4H, m), 2.82 (3H, s)
9.01 (2H, d, Jϭ5 Hz), 8.42 (1H, s), 7.67 (1H, t, Jϭ5 Hz), 7.2—7.1 (1H, m), 7.09 (2H, t, Jϭ9 Hz), 3.6—3.5 (6H, m), 3.4—
3.3 (4H, m), 3.3—3.2 (2H, m), 2.82 (3H, s)
8.36 (1H, s), 7.6—7.5 (3H, m), 7.08 (2H, s), 6.96 (1H, s), 4.0—3.9 (2H, m), 3.6—3.5 (2H, m), 3.5—3.4 (4H, m), 3.3—3.1
(4H, m), 2.54 (3H, s)
8.86 (2H, d, Jϭ5 Hz), 8.15 (1H, s), 7.34 (1H, t, Jϭ5 Hz), 7.18 (1H, dd, Jϭ15, 8 Hz), 6.67 (1H, d, Jϭ8 Hz), 6.5—6.4 (1H,
m), 6.4—6.3 (1H, m), 3.2—3.1 (4H, m), 3.09 (2H, t, Jϭ7 Hz), 3.00 (3H, s), 2.88 (2H, t, Jϭ7 Hz), 2.66 (4H, m)
8.86 (2H, d, Jϭ5 Hz), 8.15 (1H, s), 7.34 (1H, t, Jϭ5 Hz), 7.15 (1H, t, Jϭ8 Hz), 6.75 (1H, s), 6.74 (1H, d, Jϭ8 Hz), 6.68
(1H, d, Jϭ8 Hz), 3.21 (4H, t, Jϭ5 Hz), 3.10 (2H, t, Jϭ7 Hz), 3.00 (3H, s), 2.89 (2H, t, Jϭ7 Hz), 2.68 (4H, t, Jϭ5 Hz), 2.32
(3H, s)
6g
6h
6i
35
59
63
10
9
8.86 (2H, d, Jϭ4 Hz), 8.15 (1H, s), 7.4—7.3 (2H, m), 7.2—7.0 (3H, m), 3.26 (4H, t, Jϭ5 Hz), 3.10 (2H, t, Jϭ7 Hz), 3.00
(3H, s), 2.90 (2H, t, Jϭ7 Hz), 2.69 (4H, t, Jϭ5 Hz)
9.01 (2H, d, Jϭ5 Hz), 8.42 (1H, s), 7.68 (1H, dt, Jϭ8, 2 Hz), 7.79 (1H, t, Jϭ2 Hz), 7.66 (1H, t, Jϭ5 Hz), 7.54 (1H, t,
Jϭ8 Hz), 7.51 (1H, dt, Jϭ8, 2 Hz), 4.1—4.0 (2H, m), 3.8—3.6 (2H, m), 3.6—3.5 (4H, m), 3.3—3.2 (4H, m), 2.82 (3H, s)
8.86 (2H, d, Jϭ5 Hz), 8.14 (1H, s), 7.35 (1H, t, Jϭ5 Hz), 7.3—6.6 (4H, m), 3.3—3.1 (4H, m), 3.10 (2H, t, Jϭ7 Hz), 3.00
(3H, s), 2.89 (2H, t, Jϭ7 Hz), 2.7—2.6 (4H, m), 2.16 (3H, s)
8.86 (2H, d, Jϭ5 Hz), 8.12 (1H, s), 7.35 (1H, t, Jϭ5 Hz), 6.55 (1H, m), 6.51 (1H, m), 6.27 (1H, m), 3.6—3.4 (4H, m),
3.1—2.9 (4H, m), 2.98 (3H, s), 2.8—2.7 (2H, m), 2.7—2.6 (2H, m), 2.0—1.9 (2H, m)
8.86 (2H, d, Jϭ5 Hz), 8.15 (1H, s), 7.34 (1H, t, Jϭ5 Hz), 7.20 (1H, t, Jϭ2 Hz), 7.11 (2H, d, Jϭ2 Hz), 3.1—3.0 (2H, m),
2.99 (3H, s), 2.9—2.8 (2H, m), 2.8—2.7 (2H, m), 2.5—2.4 (1H, m), 2.15 (1H, dd, Jϭ14, 7 Hz), 2.0—1.8 (4H, m), 1.40
(1H, dt, Jϭ11, 7 Hz)
8
20a
20b
20c
18
8.86 (2H, d, Jϭ5 Hz), 8.13 (1H, s), 7.35 (1H, t, Jϭ5 Hz), 3.06 (2H, t, Jϭ7 Hz), 2.99 (3H, s), 2.83 (2H, t, Jϭ7 Hz), 2.7—2.4
(8H, m), 2.4—2.1 (1H, m), 2.0—1.7 (4H, m), 1.7—1.5 (2H, m), 1.3—1.0 (4H, m)
20d
20e
20f
32
35
28
9.00 (2H, d, Jϭ5 Hz), 8.36 (1H, s), 7.66 (1H, t, Jϭ5 Hz), 7.7—7.4 (5H, m), 3.8—3.2 (14H, m), 2.80 (3H, s)
9.00 (2H, d, Jϭ5 Hz), 8.38 (1H, s), 7.66 (1H, t, Jϭ5 Hz), 7.5—7.2 (10H, m), 4.49 (1H, s), 3.6—3.1 (12H, m), 2.80 (3H, s)
8.86 (2H, d, Jϭ5 Hz), 8.13 (1H, s), 7.35 (1H, t, Jϭ5 Hz), 3.62 (2H, t, Jϭ5 Hz), 3.05 (2H, t, Jϭ8 Hz), 2.99 (3H, s), 2.83
(2H, t, Jϭ8 Hz), 2.55 (2H, t, Jϭ6 Hz), 2.7—2.4 (9H, m)
with ice-water, alkalized with NaHCO3, and extracted with CHCl3. The or-
reaction mixture was quenched with a solution of 1 N HCl/EtOH, and the
ganic layer was washed with brine and dried. After removal of the solvent, solvents were removed to afford the diol. Next, sodium periodate (4.0 g) was
the crude residue was chromatographed on a silica gel column (CHCl3/ added to a solution of the above product in THF (15 ml) and water (3.0 ml),
MeOHϭ100/3) to afford the propene. An appropriate volume of a solution and the mixture was stirred at room temperature for 1 h. The mixture was di-
of 1 N HCl/EtOH was added to a solution of the propene in a small amount
of EtOH, and the solvent was removed. The residue was recrystallized from vents, the residue was chromatographed on
EtOH to give 10 (50 mg, 54%) as a white powder. The physical data for 10 (CHCl3/AcOEtϭ2/1) to give 12 (0.52 g, 75%) as a white caramel: H-NMR
luted with AcOEt, washed with brine, and dried. After removal of the sol-
a
silica gel column
1
are shown in Table 6.
2-[5-Methyl-1-(2-pyrimidinyl)-4-1H-pyrazolyl]-2-oxoethyl Acetate
(11) Bromine (0.5 ml) was added to a solution of 5 (2.0 g, 9.86 mmol) in
(CDCl3) d: 10.05 (1H, s), 8.87 (2H, d, Jϭ5 Hz), 8.17 (1H, s), 7.35 (1H, t,
Jϭ5 Hz), 3.01 (3H, s).
2-[5-Methyl-4-[1-[(triethylsilyl)oxy]-3-butenyl]-1-1H-pyrazolyl]pyrim-
AcOH (50 ml), and the mixture was stirred at 70 °C for 1.5 h. The reaction idine (13) Allyl bromide (0.16 ml, 0.6 mmol) and metallic tin (70 mg)
mixture was diluted with AcOEt, washed with saturated aqueous NaHCO3 were added to a solution of 12 (94 mg, 0.5 mmol) in THF (2.5 ml) and water
and brine, and dried. Evaporation of the solvents afforded the crude mixture, (2.5 ml), and the mixture was sonicated for 1 h in an ultrasonic cleaning bath
which was recrystallized from EtOH to give the bromoethanone (2.8 g, (Pasolina USC-1). The reaction mixture was carefully quenched with 1 N
quantitative yield) as colorless needles: 1H-NMR (CDCl3) d: 8.88 (2H, d, aqueous HCl (2.0 ml) at 0 °C, diluted with CHCl3/MeOH (95/5), washed
Jϭ5 Hz), 8.16 (1H, s), 7.37 (1H, t, Jϭ5 Hz), 4.29 (2H, s), 3.01 (3H, s).
with brine, and dried. After removal of the solvents, the residue was chro-
Cesium acetate (2.0 g, 10.42 mmol) was added to a solution of the bro- matographed on a silica gel column (CHCl3/MeOHϭ98/2) to give the alco-
moethanone (0.97 g, 3.45 mmol) in N,N-dimethylformamide (DMF, 10 ml) hol (112 mg, 97%) as a colorless amorphous solid: 1H-NMR (CDCl3) d:
at 0 °C, and the mixture was stirred at room temperature for 1.5 h. The reac- 8.77 (2H, d, Jϭ5 Hz), 7.77 (1H, s), 7.22 (1H, t, Jϭ5 Hz), 5.8—5.7 (1H, m),
tion mixture was diluted with AcOEt, washed with brine, and dried. Evapo-
5.3—5.2 (1H, m), 5.2—5.2 (1H, m), 4.76 (1H, dd, Jϭ8, 6 Hz), 2.68 (3H, s),
ration of the solvents afforded 11 (0.86 g, quantitative yield) as a pale yellow 2.7—2.4 (2H, m).
oil: 1H-NMR (CDCl3) d: 8.87 (2H, d, Jϭ5 Hz), 8.11 (1H, s), 7.37 (1H, t,
Jϭ5 Hz), 5.13 (2H, s), 3.01 (3H, s), 2.24 (3H, s).
Imidazole (100 mg, 1.46 mmol) and chlorotetraethylsilane (2.45 ml,
1.46 mmol) were added successively to a solution of the alcohol (112 mg,
5-Methyl-1-(2-pyrimidinyl)-1H-pyrazole-4-carbaldehyde (12) One 0.49 mmol) in anhydrous DMF (3.0 ml) at 0 °C, and the mixture was stirred
normal aqueous NaOH (6.0 ml) was added to a solution of 11 (0.8 g, for 12 h. Water (10 ml) was added to the mixture, and the whole was ex-
3.22 mmol) in MeOH (20 ml), and the mixture was stirred at room tempera- tracted with AcOEt. The organic layer was washed with brine and dried.
ture for 20 min. After removal of the solvents, the crude mixture was chro- After removal of the solvents, the residue was chromatographed on a silica
matographed on a silica gel column (CHCl3/MeOHϭ30/1) to afford the pri-
gel column (CHCl3/MeOHϭ99/1) to afford 13 (170 mg, quantitative yield)
1
mary alcohol (0.8 g, quantitative yield) as a white caramel: 1H-NMR as a pale yellow oil: H-NMR (CDCl3) d: 8.77 (2H, d, Jϭ5 Hz), 7.74 (1H,
(CDCl3) d: 8.88 (2H, d, Jϭ5 Hz), 8.06 (1H, s), 7.38 (1H, t, Jϭ5 Hz), 4.70
(2H, s), 3.05 (3H, s), 2.5—2.4 (1H, m).
Sodium borohydride (0.3 mg) was added to a solution of the primary alco-
hol (0.81 g, 3.69 mmol) in EtOH (20 ml) and tetrahydrofuran (THF, 10 ml)
s), 7.19 (1H, t, Jϭ5 Hz), 5.8—5.7 (1H, m), 5.1—5.0 (2H, m), 4.72 (1H, t,
Jϭ8 Hz), 2.65 (3H, s), 2.6—2.5 (1H, m), 2.5—2.3 (1H, m), 0.90 (9H, t,
Jϭ8 Hz), 0.55 (6H, m).
3-[5-Methyl-1-(2-pyrimidinyl)-4-1H-pyrazolyl]-3-[(triethylsilyl)oxy]-
at 0 °C, and the mixture was stirred at the same temperature for 20 min. The propanal (14) 4-Methylmorpholine N-oxide (NMO, 1.08 g, 9.22 mmol)

April 2002
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and a catalytic amount of osmium tetraoxide were added to a solution of 13
ford the mixture of 19b and 3-(3,5-dichlorophenyl)piperidine (800 mg,
(1.59 g, 4.61 mmol) in THF (20 ml) and water (5 ml), and the mixture was quantitative yield as the mixture) as a pale red oil. This mixture was used in
stirred at room temperature for 24 h. A suspension of sodium periodate the next Mannich reaction without further purification: FAB-MS m/z 228
(4.93 g, 23.1 mmol) in water (20 ml) was added to the above mixture at room (MϩϩH).
temperature, and the mixture was stirred at the same temperature for 2 h.
3-[4-(3,5-Difluorophenyl)-1-(1,4-diazepanyl)]-1-[5-methyl-1-(2-pyrim-
The mixture was diluted with CHCl3, washed with brine, and dried. After re- idinyl)-4-1H-pyrazolyl]-1-propanone (20a) Synthesis of 20a—f from
moval of the solvents, the residue was chromatographed on a silica gel col- 19a—f was performed as described for the synthesis of 6a. The physical
umn (CHCl3/MeOHϭ99/1) to give 14 (0.91 g, 57%) as a pale yellow oil: 1H- data for 20a—f are shown in Table 5.
NMR (CDCl3) d: 9.81 (1H, t, Jϭ2 Hz), 8.78 (2H, d, Jϭ5 Hz), 7.77 (1H, s),
7.22 (1H, t, Jϭ5 Hz), 5.27 (1H, dd, Jϭ8, 5 Hz), 2.97 (1H, ddd, Jϭ16, 8,
3-[4-(3,5-Dichlorophenyl)-1-piperidinyl]-1-[5-methyl-1-(2-pyrim-
idinyl)-4-1H-pyrazolyl]-1-trans-propene Hydrochloride (21a) Synthesis
2 Hz), 2.73 (3H, s), 2.7—2.6 (1H, m), 0.89 (9H, t, Jϭ8 Hz), 0.5—0.4 (6H, of 21a—l from 20a—l was performed as described for the synthesis of 7a.
m).
3-[4-(3-Hydroxyphenyl)-1-piperazinyl]-1-[5-methyl-1-(2-pyrimidinyl)-
The physical data for 21a—l are shown in Table 6.
N1-(3,5-Difluorophenyl)-1,2-ethanediamine Hydrochloride (23) The
4-1H-pyrazolyl]-1-trans-propene Hydrochloride (16) AcOH (220 ml, mixture of 3,5-difluoroaniline hydrochloride (22, 10.6 g, 64 mmol) and 1,3-
3.88 mmol) and sodium cyanoborohydride (305 mg, 4.85 mmol) were added oxazolidin-2-one (5.6 g, 64 mmol) was stirred at 170 °C for 4 d. The reaction
successively to a solution of 14 (336 mg, 0.970 mmol) and 15 (864 mg, mixture was cooled, and the precipitate obtained was filtered. The precipitate
4.85 mmol) in MeOH (170 ml), and the mixture was stirred at room temper- was recrystallized from Et2O to give 23 (13.7 g, quantitative yield) as a pale
ature for 2.5 h. The reaction mixture was diluted with CHCl3, washed with red powder: 1H-NMR (CDCl3) d: 6.45 (2H, d, Jϭ9 Hz), 6.35 (1H, t,
saturated aqueous NaHCO3 and brine, and dried. Evaporation of the solvents Jϭ9 Hz), 4.30 (2H, t, Jϭ8 Hz), 3.72 (3H, br s), 3.55 (2H, t, Jϭ8 Hz).
afforded the corresponding adduct. Next, a solution of 1 N HCl/EtOH (10 ml)
was added to a solution of the above product in EtOH (10 ml), and the mix-
4-(3,5-Difluorophenyl)-3-methyl-2-piperazinone (24) Et3N (15 ml)
and 2-chloropropanoyl chloride (3.0 ml, 30.9 mmol) were successively added
ture was stirred at room temperature for 17 h. After removal of the solvents, dropwise to a solution of 23 (2.6 g, 15.1 mmol) in CH2Cl2 (10 ml) at 0 °C,
the crude mixture was dissolved in THF (15 ml) and 1,4-dioxane (15 ml). p- and the mixture was stirred at the same temperature for 20 min. The reaction
TsOH·H2O (275 mg, 1.45 mmol) was added to a solution of the crude mix- mixture was diluted with CHCl3, washed with 10% aqueous NaOH and
ture in anhydrous 1,4-dioxane (5 ml) and THF (5 ml), and the mixture was brine, and dried. Removal of the solvents afforded the corresponding amide.
heated to reflux for 2 h. The reaction mixture was diluted with CHCl3, suc-
Next, K2CO3 (3.0 g) was added to a solution of the above product in EtOH
cessively washed with saturated aqueous NaHCO3 and brine, and dried. (50 ml), and the mixture was heated to reflux for 41 h. The mixture was di-
After removal of the solvents, the crude mixture was chromatographed on a luted with CHCl3, washed with 10% aqueous NaOH and brine, and dried.
silica gel column (CHCl3/MeOHϭ50/3) to afford the propene. An appropri- After removal of the solvents, the residue was chromatographed on a silica
ate volume of a solution of 1 N HCl/EtOH was added to a solution of the
gel column (CHCl3/MeOHϭ40/1) to give 24 (1.2 g, 35%) as a yellow oil:
propene in a small amount of EtOH, and the solvent was removed. The 1H-NMR (CDCl3) d: 6.45 (2H, d, Jϭ9 Hz), 6.34 (1H, t, Jϭ9 Hz), 4.0—3.9
residue was recrystallized from EtOH to give 16 (113 mg, 25%) as a white (2H, m), 3.8—3.5 (3H, m), 1.34 (3H, d, Jϭ6.8 Hz).
powder. The physical data for 16 are shown in Table 6.
1-(3,5-Difluorophenyl)-2-methylpiperazine (26a) A solution of 24
3-(3,5-Dichlorophenyl)cyclopentanone (18b) 2-Cyclopentenone (2.2 (400 mg, 1.8 mmol) in THF (20 ml) was added to a suspension of LAH
g, 27 mmol), palladium(II) acetate (940 mg), tris(2-methylphenyl)phosphine (200 mg, 5.3 mmol) in THF (20 ml), and the mixture was stirred at room
(112 mg), and Et3N (4.3 ml, 31 mmol) were added to a solution of 1-bromo- temperature for 5 h. The reaction mixture was carefully quenched with
3,5-dichlorobenzene (17b, 5.9 g, 26 mmol) in CH3CN (8.0 ml), and the mix- AcOEt, and the whole was filtered through a Celite pad. The filtrate was
ture was heated to reflux for 3 weeks. The reaction mixture was diluted with washed with brine, and dried. After removal of the solvents, the crude mix-
CHCl3, washed with 1 N HCl and brine, and dried. After removal of the sol- ture was chromatographed on a silica gel column (CHCl3/MeOHϭ20/1) to
1
vents, the crude mixture was chromatographed on a silica gel column
afford 26a (60 mg, 32%) as a yellow oil: H-NMR (CDCl3) d: 6.46 (2H, d,
(CHCl3) to afford 18b (1.13 g, 19%) as a colorless clear oil: 1H-NMR Jϭ9 Hz), 6.38 (1H, t, Jϭ9 Hz), 4.30 (1H, br s), 4.0—3.7 (1H, m), 3.7—3.6
(CDCl3) d: 7.26 (1H, t, Jϭ2 Hz), 7.14 (2H, d, Jϭ2 Hz), 3.38 (1H, ddt, (2H, m), 3.6—3.5 (3H, m), 2.78 (1H, dd, Jϭ12, 3 Hz), 2.46 (1H, dd, Jϭ12,
Jϭ14, 11, 7 Hz), 2.67 (1H, dd, Jϭ14, 7 Hz), 2.4—2.3 (2H, m), 2.6—2.4 9 Hz), 1.18 (3H, d, Jϭ7 Hz).
(2H, m), 1.97 (1H, dt, Jϭ11, 7 Hz).
1-(3,5-Difluorophenyl)-1,4-diazepane (19a) 1,4-Diazepane (2.0 g, 20.7
1-(3,5-Difluorophenyl)-3-methylpiperazine (26b) 2-Methylpiperazine
(623 mg, 6.22 mmol) was treated in the same manner as for 19a to give 26b
mmol), dichlorobis(tri-o-tolylphosphine)palladium (122 mg, 0.155 mmol), (346 mg, 32%) as a pale yellow oil: 1H-NMR (CDCl3) d: 6.3—6.2 (2H, m),
and sodium tert-butoxide (695 mg, 7.23 mmol) were added to a solution of 6.24 (1H, tt, Jϭ9, 2 Hz), 3.4—3.3 (2H, m), 3.1—3.0 (1H, m), 2.98 (1H, dt,
1-bromo-3,5-difluorobenzene (17a, 1.0 g, 5.18 mmol) in toluene (25 ml), and Jϭ12, 3 Hz), 2.9—2.8 (1H, m), 2.75 (1H, dt, Jϭ12, 3 Hz), 2.39 (1H, dd,
the mixture was stirred at 100 °C for 13 h. The reaction mixture was washed Jϭ12, 10 Hz),1.14 (3H, d, Jϭ6 Hz).
with water and brine, and dried. After removal of the solvents, the crude
mixture was chromatographed on a silica gel column (CHCl3/MeOHϭ9/1) pyrimidinyl)-4-1H-pyrazolyl]-1-trans-propene Hydrochloride (27a)
to afford 19a (346 mg, 32%) as a pale yellow oil: 1H-NMR (CDCl3) d: 6.5—
Compounds 26a and 26b were treated in the same manner as described
6.4 (1H, m), 6.51 (1H, dt, Jϭ8, 2 Hz), 6.28 (1H, dt, Jϭ13, 2 Hz), 3.6—3.5 above to give 27a and 27b, respectively. The physical data for these com-
3-[4-(3,5-Difluorophenyl)-3-methyl-1-piperazinyl]-1-[5-methyl-1-(2-
(4H, m), 3.02 (2H, t, Jϭ5 Hz), 2.84 (2H, t, Jϭ5 Hz), 2.0—1.9 (2H, m).
4-(3,5-Difluorophenyl)piperidine (19b) Sodium acetate (1.3 g) and hy-
pounds and yields are shown in Table 6.
Benzyl 4-(3,5-Difluorophenyl)-3-oxo-1-piperazinecarboxylate (28)
droxylamine hydrochloride (0.68 g, 9.9 mmol) were added to a solution of Et3N (1.20 ml, 8.57 mmol) and ZCl (0.665 ml, 3.9 mmol) were successively
18b (1.13 g, 5.0 mmol) in MeOH (20 ml) and water (10 ml), and the mixture added dropwise to a solution of 23 (813 mg, 3.9 mmol) in anhydrous THF
was heated to reflux for 2 h. The reaction mixture was diluted with CHCl3, (10 ml) at 0 °C, and the mixture was stirred at room temperature for 4 h. The
washed with water and brine, and dried. Removal of the solvents afforded reaction mixture was diluted with CHCl3, washed with brine, and dried.
the corresponding oxime. To this residue was added polyphosphoric acid After removal of the solvents, the crude mixture (800 mg) was dissolved in
(10 g), and the mixture was stirred at 80 °C for 2 h. The reaction mixture was AcOEt (7.5 ml). 2-Bromoactyl bromide (0.71 ml, 8.22 mmol) and a solution
diluted with ice-water, neutralized with NaHCO3, and extracted with CHCl3. of NaOH (411 mg, 10.3 mmol) were added successively to the above solu-
The organic layer was washed with brine and dried. After removal of the sol- tion at 0 °C, and the mixture was stirred at room temperature for 6 h. The re-
vents, the crude mixture was chromatographed on a silica gel column action mixture was diluted with CHCl3, washed with brine, and dried. Re-
(CHCl3/AcOEtϭ1/1) to afford the mixture of 4-(3,5-dichlorophenyl)-2- moval of the solvents afforded the corresponding amide (1.1 g). Next,
piperidinone and 5-(3,5-dichlorophenyl)-2-piperidinone (800 mg, 66%) as a K2CO3 (1.07 g, 7.73 mmol) was added to a solution of the above product in
red caramel. The ratio of 4-(3,5-dichlorophenyl)-2-piperidinone and the iso- DMF (6 ml), and the mixture was stirred at room temperature for 48 h. The
mer was about 1 : 1 based on the NMR spectrum. This mixture was used in mixture was diluted with CHCl3, washed with brine, and dried. After re-
the next reaction without further purification: FAB-MS m/z 244 (MϩϩH).
A
moval of the solvents, the residue was chromatographed on a silica gel col-
solution of the mixture of the above 2-piperidinones (800 mg, umn (CHCl3/MeOHϭ50/1) to give 28 (800 mg, 59%) as a yellow oil: 1H-
3.3 mmol) in THF (20 ml) was added to a suspension of LAH (370 mg,
NMR (CDCl3) d: 7.5—7.2 (5H, m), 7.0—6.8 (1H, m), 6.8—6.7 (1H, m),
9.7 mmol) in THF (40 ml) at 0 °C, and the mixture was heated to reflux for 5.19 (2H, s), 4.33 (2H, s), 4.0—3.8 (2H, m), 3.8—3.6 (2H, m).
5 h. The reaction mixture was carefully quenched with AcOEt, and the 1-(3,5-Difluorophenyl)-2-piperazinone (29) Compound 28 (800 mg,
whole was filtered through a Celite pad. The filtrate was concentrated to af- 2.31 mmol) was dissolved in EtOH (40 ml) and hydrogenated over 10%

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Vol. 50, No. 4
Evaluation of Therapeutic Effect in Vivo P388 cells (1ϫ106) were in-
oculated i.p. into CDF1 mice (6 mice per group) on day 0. Compounds were
suspended in BTC salt solution (0.9% benzyl alcohol, 0.4% Tween 80, 0.5%
carboxymethyl cellulose, 0.9% NaCl) and administered i.p. or p.o. on days 1
and 5, or days 1—5 consecutively. The increase in life span (ILS) was calcu-
lated by the following formula: ILS (%)ϭ[(median survival time of treated
group)/(median survival time of control group)Ϫ1]ϫ100. Meth A murine fi-
brosarcoma cells (1ϫ106) were implanted into the right flank of BALB/c
mice (day 0). Compounds were administered p.o. on days 7—11 consecu-
tively. Tumor weights were measured on day 17. The tumor growth-inhibi-
tion rate (IR) was calculated by the formula: IR (%)ϭ(1ϪTWt/TWc)ϫ100
(%), where TWt represents the mean of tumor weight of a treated group, and
TWc represents that of the control group. To evaluate the intensity of the
side effects of compounds, the rate of body weight loss (BWL) was utilized
as a parameter of toxicity. The maximum value of BWL was designated as
BWLmax, and a BWLmax of less than zero indicates no body weight loss.
Pd/C (250 mg) for 10 min at room temperature. The reaction mixture was
filtered through a Celite pad, and the filtrate was evaporated to afford
the crude mixture, which was chromatographed on a silica gel column
(CHCl3/MeOHϭ30/1) to give 29 (326 mg, 67%) as a yellow oil: H-NMR
(CDCl3) d: 7.0—6.8 (2H, m), 6.8—6.6 (2H, m), 3.70 (2H, s), 3.68 (2H, t,
Jϭ5 Hz), 3.23 (2H, t, Jϭ5 Hz).
1
3-Hydroxy-3-[5-methyl-1-(2-pyrimidinyl)-4-1H-pyrazolyl]propyl-4-
methyl-benzenesulfonate (30) Sodium borohydride (38 mg, 1.0 mmol)
was added to a solution of 14 (328 mg, 0.95 mmol) in MeOH (4.0 ml) at
0 °C, and the mixture was stirred at the same temperature for 1 h. A solution
of 1 N HCl/EtOH (1.0 ml) and water (20 ml) was successively added to the
reaction mixture, and the whole was extracted with CHCl3. The organic
layer was dried and then evaporated in vacuo to afford the primary alcohol
(296 mg). Next, p-toluenesulfonyl chloride (361 mg, 1.84 mmol) was added
to a solution of the above product in pyridine (3.0 ml) at 0 °C, and the mix-
ture was stirred at the same temperature for 24 h. The mixture was diluted
with CHCl3, washed with brine, and dried. After removal of the solvents, the
residue was chromatographed on a silica gel column (CHCl3/MeOHϭ95/5)
to give the tosylate, which was kept in a refrigerator overnight to afford 30
(350 mg, 74%) as a pale yellow oil: 1H-NMR (CDCl3) d: 8.79 (1H, d,
Jϭ5 Hz), 7.80 (2H, d, Jϭ8 Hz), 7.70 (1H, s), 7.35 (2H, d, Jϭ8 Hz), 7.24
(1H, t, Jϭ5 Hz), 4.88 (1H, dd, Jϭ5, 9 Hz), 4.4—4.3 (1H, m), 4.2—4.1 (1H,
m), 2.66 (3H, s), 2.44 (3H, s), 2.2—2.1 (1H, m), 2.1—2.0 (1H, m).
3-[4-(3,5-Difluorophenyl)-3-oxo-1-piperazinyl]-1-[5-methyl-1-(2-pyrim-
idinyl)-4-1H-pyrazolyl]-1-propene Hydrochloride (31) Compound 29
(33 mg, 0.15 mmol) and K2CO3 (11 mg) were added to a solution of 30
(30 mg, 0.077 mmol) in CH3CN (1 ml) and THF (10 ml), and the mixture
was stirred at 60 °C for 30 min. The reaction mixture was diluted with
CHCl3, washed with brine, and then dried. Evaporation of the solvents
afforded the corresponding adduct. Next, p-TsOH·H2O (50 mg, 0.263
mmol) was added to a solution of the above product in anhydrous 1,4-diox-
ane (3 ml) and THF (3 ml), and the mixture was heated to reflux for 40 min.
The reaction mixture was diluted with CHCl3, successively washed with
saturated aqueous NaHCO3 and brine, and dried. After removal of the
solvents, the crude mixture was chromatographed on a silica gel column
(CHCl3/MeOHϭ98/2) to afford the propene. An appropriate volume of a so-
lution of 1 N HCl/EtOH was added to a solution of the propene in a small
amount of EtOH, and the solvent was removed. The residue was recrystal-
lized from EtOH to give 31 (14 mg, 51%) as a white powder. The physical
data and yields are shown in Table 6.
References and Notes
1) Naito H., Sugimori M., Mitsui I., Nakamura Y., Ishii M., Iwahana M.,
Hirotani K., Kumazawa E., Ejima A., Chem. Pharm. Bull., 47, 1679—
1684 (1999).
2) Compounds 4e, g, and h, were commercially available. The synthesis
of 4f; Martin G. E., Elgin R. J., Jr., Mathiasen J. R., Davis C. B.,
Kesslick J. M., Baldy W. J., Shank R. P., DiStefano D. L., Fedde C. L.,
Scott M. K., J. Med. Chem., 32, 1052—1056 (1989), 4i; Lopez-Ro-
driguez M. L., Morcillo M. J., Fernandez E., Rosado M. L., Orensanz
L., Beneytez M. E., Manzanares J., Fuentes J. A., Schaper Klaus-Jur-
gen., Bioorg. Med. Chem. Lett., 9, 1679—1682 (1999).
3) Ueno K., Ohmura Y., Moroi R., Akashi A., Ger. Patent 2038503
[Chem. Abstr., 75, 49121c (1971)].
4) Mukaiyama T., Harada T., Chem. Lett., 1981, 1527—1528.
5) Zhao S.-H., Miller A. K., Berger J., Flippin L. A., Tetrahedron Lett.,
37, 4463—4466 (1996).
6) Cortese N. A., Ziegler C. B., Hrnjez B. J., Heck R. F., J. Org. Chem.,
43, 2952—2958 (1978).
7) Poindexter G. S., Owens D. A., Dolan P. L., Woo E., J. Org. Chem., 57,
6257—6265 (1992).
8) Barr W. H., Riegelman S., J. Pharm. Sci., 59, 154—163 (1970).
9) Ishii M., Iwahana M., Mitsui I., Minami M., Imagawa S., Tohgo A.,
Ejima A., Anticancer Drugs, 11, 353—362 (2000).
10) Iwahana M., Ochi Y., Ejima A., Anticancer Research, 20, 785—792
(2000).
11) Mitsui I., Kumazawa E., Aonuma M., Sugimori M., Ohsuki S., Uoto
K., Ejima A., Terasawa H., Sato K., Jpn. J. Cancer Res., 86, 776—782
(1995).
In Vitro Cytotoxicity To examine the direct growth-inhibitory effects of
the test compounds against PC-6 and PC-12 human non-small cell lung can-
cer cell lines and resistant cell lines (PC-6/VCR and PC-6/ADM), the 3-
(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay
was performed, and the concentration giving a growth inhibition of 50%
(GI50) was calculated according to a published procedure.9)