(Phenylpiperazinyl-butyl)oxindoles as selective 5-HT7 receptor antagonists

Article abstract of DOI:10.1021/jm070279v

A series of potent 5-hydroxytryptamine₇ (5-HT₇) ligands has been synthesized that contain a 1,3-dihydro2H-indol-2-one (oxindole) skeleton. The binding of these compounds to the 5-HT₇ and 5-HT _1A receptors was measured. Despite the structural similarity of these two serotonin receptor subtypes, several derivatives exhibited a high selectivity to the 5-HT₇ receptor. According to the structure-activity relationship observations, compounds unsubstituted at the oxindole nitrogen atom and containing a tetramethylene spacer between the oxindole skeleton and the basic nitrogen atom are the most potent ligands. Concerning the basic group, besides the moieties of the 4-phenylpiperazine type, halophenyl-1,2,3,6-tetrahydropyridines also proved to be 5-HT₇ receptor-ligands. Because of halogen substitution on the aromatic rings, good metabolic stability could be achieved. A representative of the family, 3-{4-[4-(4-chlorophenyl)-piperazin-1-yl]-butyl}-3-ethyl-6-fluoro-1, 3-dihydro-2H-indol-2-one (9e′) exhibited selective 5-HT₇ antagonist activity (K: = 0.79 nM). The in vivo pharmacological potencies of these 5-HT₇ receptor-ligands were estimated by the conflict drinking (Vogel) and the light-dark anxiolytic tests.

Full text of DOI:10.1021/jm070279v

2522
J. Med. Chem. 2008, 51, 2522–2532
(Phenylpiperazinyl-butyl)oxindoles as Selective 5-HT7 Receptor Antagonists
Balázs Volk,*,† József Barkóczy,† Endre Hegedus,‡ Szabolcs Udvari,‡ István Gacsályi,‡ Tibor Mezei,† Katalin Pallagi,‡
Hajnalka Kompagne,‡ György Lévay,‡ András Egyed,‡ László G. Hársing, Jr.,‡ Michael Spedding,§ and Gyula Simig†
Chemical Research DiVision and Preclinical Research DiVision, EGIS Pharmaceuticals Plc, P.O. Box 100, H-1475 Budapest, Hungary, and
Institut de Recherches SerVier, 11 rue des Moulineaux, 92150 Suresnes, France
ReceiVed March 12, 2007
A series of potent 5-hydroxytryptamine7 (5-HT7) ligands has been synthesized that contain a 1,3-dihydro-
2H-indol-2-one (oxindole) skeleton. The binding of these compounds to the 5-HT7 and 5-HT1A receptors
was measured. Despite the structural similarity of these two serotonin receptor subtypes, several derivatives
exhibited a high selectivity to the 5-HT7 receptor. According to the structure–activity relationship observations,
compounds unsubstituted at the oxindole nitrogen atom and containing a tetramethylene spacer between the
oxindole skeleton and the basic nitrogen atom are the most potent ligands. Concerning the basic group,
besides the moieties of the 4-phenylpiperazine type, halophenyl-1,2,3,6-tetrahydropyridines also proved to
be 5-HT7 receptor–ligands. Because of halogen substitution on the aromatic rings, good metabolic stability
could be achieved. A representative of the family, 3-{4-[4-(4-chlorophenyl)-piperazin-1-yl]-butyl}-3-ethyl-
6-fluoro-1,3-dihydro-2H-indol-2-one (9e′) exhibited selective 5-HT7 antagonist activity (Ki ) 0.79 nM).
The in vivo pharmacological potencies of these 5-HT7 receptor–ligands were estimated by the conflict drinking
(Vogel) and the light-dark anxiolytic tests.
Introduction
The 5-HT7 receptor is the last addition to the serotonin
subfamily of G-protein coupled receptors.1,2 Although the
functional significance of this receptor is largely unknown,
several reports have associated the human 5-HT7 receptor with
a variety of CNSa functions and disorders such as schizophre-
nia,3 depression,4–7 epilepsy,8 migraine,9,10 and control of
circadian rhythm.11,12 Therefore, the 5-HT7 receptor may be a
novel and valuable drug target, so the development of its potent
ligands is of key importance.
In recent years, some selective 5-HT7 receptor antagonists
have been reported.13–18 Also, papers have been published on
selective15,19 and nonselective agonists20,21 and partial agonists
Figure 1. Tetrahydrobenzindole 5-HT7 antagonists.
at the 5-HT7 receptor.15,19,22 However, the number of com-
pounds had been realized, the authors synthesized halogen-
substituted derivatives, e.g., 4 (DR4485), with increased in vitro
metabolic stability.27 However, the measured value of bioavail-
ability (18% in rats for 4) was still quite low.
pounds reported in the literature is still quite low. Additionally,
some of the potent compounds caused strong side-effects (e.g.,
blood pressure and heart rate changes20) or showed poor
metabolic stability in animal experiments.
Kikuchi et al. have achieved remarkable success during the
study of the tetrahydrobenzindole family and patented these
compounds as agents against depression and anxiety.23 The first
representatives of this family of compounds showed high affinity
for the 5-HT7 and also for the 5-HT2 receptors.23 Later on, the
(2-methoxyphenyl)piperazinyl derivative (1, Figure 1) proved
to be a selective 5-HT7 antagonist (pKi ) 8.67).24 The selectivity
over 5-HT2 and other 5-HT receptors was further increased with
fused ring analogues 2 (DR4365) and 3 (DR4446).25,26 After
serious problems with the oral bioavailability of these com-
Chemistry
We aimed at elaborating an efficient synthesis of new
compounds containing an oxindole skeleton, which can be
formally deduced from the tetrahydrobenzindoles by opening
the saturated carbocycle. It was assumed that the replacement
of the carbocycle by simple alkyl groups at position 3 of the
oxindole scaffold or the complete omission of this carbocycle
would result in less rigid and less lipophilic compounds (in order
to fulfill the requirements of the Lipinski’s Rule), hopefully with
strong 5-HT7 receptor affinity and good selectivity over other
receptors. We expected to achieve satisfactory metabolic stability
in addition to the required receptor binding profile by introducing
various substituents to both aromatic rings. Therefore, our aim
was to synthesize such substituted derivatives as well.
* To whom correspondence should be addressed. Phone: +36 1 2655874.
Fax: +36 1 2655613. E-mail: volk.balazs@egis.hu.
†
Chemical Research Division, EGIS Pharmaceuticals Plc.
Preclinical Research Division, EGIS Pharmaceuticals Plc.
Institut de Recherches Servier.
‡
§
a Abbreviations: CNS, central nervous system; n-BuLi, n-butyllithium;
Ra-Ni, Raney nickel; cAMP, cyclic adenosine monophosphate; CHO,
Chinese hamster ovary; 5-CT, 5-carboxytryptamine; TMS tetramethylsilane;
8-OH-DPAT, 8-hydroxy-2-(di-n-propylamino)-tetralin; DMEM, Dulbecco’s
modified Eagle’s medium with Ham’s F-12; EIA, enzyme immunoassay;
BCA, bicinchoninic acid; Tris, tris(hydroxymethyl)aminomethane.
Despite the structural similarity of oxindoles with tetrahy-
drobenzindoles, a new synthetic approach was needed. The
planned synthetic route to the title compounds made the
preparation of 3-alkyloxindole intermediates necessary. We suc-
ceeded in elaborating a novel, practical synthesis of these
10.1021/jm070279v CCC: $40.75
2008 American Chemical Society
Published on Web 03/25/2008

(Phenylpiperazinyl-butyl)oxindoles as 5-HT7 Antagonists
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 8 2523
Scheme 2a
Scheme 1a
a Reagents and conditions: (a) NaH, MeI or BnCl, DMF, from 0 °C to
rt, 1 h; 76–86%; (b) subst. phenylpiperazine, Na2CO3, in melt, 180 °C,
1.5 h, 56–71%.
The corresponding N-alkylated derivatives were synthesized
by the alkylation of 3-(4-chlorobutyl)-3-ethyloxindole (7b) with
methyl iodide or benzyl chloride after deprotonation with sodium
hydride (Scheme 2). The N-alkyl derivatives 13 were then
treated with the appropriate arylpiperazines, resulting in com-
pounds 14.
a Reagents and conditions: (a) R1OH, Ra-Ni, 15 bar H2, 180–210 °C,
3–5 h, 71–91%; (b) n-BuLi, Br-(CH2)n-Hlg, THF, from -78 °C to rt, 4 h,
82–94%; (c) Chlorination at position 5: SO2Cl2, cc. AcOH, 16–18 °C, 2 h,
86–91%; 7-chlorination or 5,7-dichlorination: SO2Cl2, cc. AcOH, 60 °C,
3 h, 67–79%; (d) HNR2R3, Na2CO3, in melt, 180 °C, 1–2 h, 32–88%; (e)
HO-(CH2)4-OH, Ra-Ni, 15 bar H2, 190 °C, 4–5 h, 75–81%; (f) MeSO2Cl,
Et3N, THF, from -78 °C to rt, 1–2 h, 81–93%; (g) subst. phenylpiperazine,
Na2CO3, in melt, 120 °C, 1 h, 52–87%.
Results and Discussion
The examination of the 5-HT7 receptor binding site revealed
its close similarities to that of the 5-HT1A receptor,35 which can
explain dual activity and difficulties in developing selective
ligands for the 5-HT7 receptor. Therefore, all the synthesized
compounds were primarily evaluated for their binding affinities
for human 5-HT7 and rat 5-HT1A receptors, in vitro. The
pharmacological activity of the compounds was also determined
in two anxiolytic tests, the conflict drinking (Vogel) test36 in
rats and the light-dark test37 in mice. The minimal effective
doses (MED, mg/kg ip.) calculated in these anxiolytic tests are
listed in Tables 1-7.
First of all, experiments were performed for the determination
of the optimal spacer length. The results in Table 1 led us to
the conclusion that among the (3-chlorophenyl)piperazine
derivatives, the one with a tetramethylene spacer (n ) 4)
between the oxindole skeleton and the basic group (9b) was
superior to other spacer lengths in terms of 5-HT7 receptor
affinity and selectivity over 5-HT1A receptor. The derivative with
a C5 alkyl chain (9c) demonstrated slightly lower 5-HT7 affinity,
while compound 9a, containing a C3 spacer, showed very strong
undesired binding to the 5-HT1A receptor and was not further
evaluated. The corresponding (4-chlorophenyl)piperazine de-
rivatives (9d, 9e) also exhibited high 5-HT7 affinity and
confirmed the supremacy of the C4 spacer. In case of 9d, strong
5-HT7 receptor binding was accompanied by good in vivo
efficacy (Vogel: 10 mg/kg). Concerning the distance between
the carbonyl group and the piperazine moiety, our results are
in accordance with the observations of Perrone and co-work-
ers:21 in a structurally related family of compounds, the authors
found the same spacer length ideal in terms of selectivity over
5-HT1A receptor.
compounds, starting from isatins,28–30 which circumvents the
usual problem of N-alkylation and C(3)-dialkylation of
oxindoles.31–33 By means of this new method, it was possible
to synthesize a wide variety of the desired compounds.
The synthetic procedures to the 3-mono and 3,3-disubstituted
target compounds are illustrated in Scheme 1. Isatin (5, X )
H) is commercially available, the substituted isatins (5, X )
5-F, 6-F) were synthesized, starting from anilines, by the
classical Sandmeyer procedure.34 The one-pot reductive alky-
lation of these starting materials (with alcohols, in the presence
of Raney nickel) to the corresponding 3-alkyloxindoles (6) was
performed by the method elaborated at our laboratory.29
Selective C(3)-alkylation of compounds 6 was carried out using
ω-dihaloalkanes after deprotonation with n-BuLi,33 resulting in
3-alkyl-3-(ω-haloalkyl)oxindole intermediates (7). Chlorination
of compounds 7 afforded the corresponding mono and dichloro
derivatives 8. Reaction of 7b and 7d with sulfuryl chloride (3
equiv) in glacial acetic acid at 16–18 °C yielded selectively the
5-chloro derivatives (8a and 8b), while at 60 °C, position 7
was also affected, thus 7-chloro-5-fluoro (7c f 8d) or 5,7-
dichloro (7b f 8c) analogues were obtained. Finally, replace-
ment of the side-chain halogen atom with various secondary
amines led to the target compounds 9. When necessary, the
product was purified by column chromatography. In cases where
the base was not a crystalline compound, the oily products were
converted into their hydrochloride or oxalate salts.
A different route was applied for the synthesis of the
3-monosubstituted derivatives (Scheme 1). Isatins (5) were
reductively hydroxyalkylated with butane-1,4-diol in the pres-
ence of Raney nickel to afford 3-(4-hydroxybutyl)oxindoles
(10).29 Mesylation of compounds 10 with methanesulfonyl
chloride to derivatives 11, followed by treatment with the
appropriate arylpiperazines led to the desired compounds 12.
Finally, the crude products were purified by column chroma-
tography and, if necessary, they were converted into their
hydrochloric salts.
A short study was conducted regarding the impact of the
substitution of the oxindole nitrogen atom on 5-HT7 and 5-HT1A
receptor affinities. Considering the affinity data of the two
compounds bearing a substituent at the oxindole nitrogen atom
(14a, 14b, Table 2), it was demonstrated that substitution at
the oxindole nitrogen atom was detrimental: it reduced 5-HT7
affinity and enhanced 5-HT1A receptor binding at the same time.
This observation is particularly interesting in comparison with

2524 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 8
Volk et al.
Table 1. Human Recombinant 5-HT7 and Rat 5-HT1A Receptor Affinities of Compounds 9: The Effect of Spacer Length
5-HT1A % inhibitiona
conflict drinking
light-dark testc
MED (mg/kg ip)
a
compound
n
W
5-HT7 Ki (nM)
10-7
M
10-8
M
testb MED (mg/kg ip)
9a
9b
9c
9d
9e
3
4
5
4
5
3′-Cl
3′-Cl
3′-Cl
4′-Cl
4′-Cl
21
91
42
43
11
11
57
11
12
2
>20
>20
>10
10
3
0.41
1.45
0.38
1.24
>10
>10
>10
NDd
0
>20
a Receptors and radioligands used in binding assays and data analysis: see Experimental Section. b A modification of the Vogel36 method was used for
the conflict drinking test in rats, drugs were administered intraperitoneally. For details, see Experimental Section. c Testing of drugs in the light-dark test
was carried out in mice as described by Costall37 after intraperitoneal administration of the drugs. For details, see Experimental Section. d Not determined.
Table 2. Human Recombinant 5-HT7 and Rat 5-HT1A Receptor Affinities of Compounds 9 and 14: The Effect of Oxindole Nitrogen Substitution
5-HT1A % inhibitiona
conflict drinking
light-dark testa
MED (mg/kg ip)
a
compound
R4
W
5-HT7 Ki (nM)
10-7
M
10-8
M
testa MED (mg/kg ip)
9f
14a
9g
H
Me
H
H
H
2.07
33.38
5.38
26
42
79
86
6
10
20
10
NDa
ND
ND
ND
12
28
32
2′-MeO
2′-MeO
14b
Bn
6.57
>20
a See Table 1 for details,
Table 3. Human Recombinant 5-HT7 and Rat 5-HT1A Receptor Affinities of Compounds 9 and 12: Role of the Substituent at Position 3
5-HT1A % inhibitiona
conflict drinking
light-dark testa
compound
R1
Et
H
Et
H
i-Bu
Et
H
Et
H
X
W
5-HT7aa Ki (nM)
10-7
M
10-8
M
testa MED (mg/kg ip)
MED (mg/kg ip)
9h
12a
9i
12b
9j
9b
12c
9d
12d
12e
5-F
5-F
5-F
5-F
H
H
H
H
H
3′-Cl
3′-Cl
4′-F
2.11
1.96
1.5
24
43
7
NDa
<5
>20
>20
>10
10
>10
ND
ND
ND
ND
ND
ND
11
9
2
ND
5
4′-F
3.4
6
ND
3′-Cl
3′-Cl
3′-Cl
4′-Cl
4′-Cl
H
1.80
0.41
0.49
0.38
7.0
12
42
40
11
10
33
>10
>10
>10
>10
<1
>20
<5
10
<2.5
<10
H
5-F
44
ND
a See Table 1 for details.
the previous findings in the tetrahydrobenzindole family in
which small N-alkyl groups increased 5-HT7 receptor binding
(see 3, Figure 1).26
metabolic stability, 3,3-disubstituted compounds proved to be
more favorable for further development.
When compared with the corresponding 3-isobutyl analogue
9j, the 3-ethyl compound 9b proved to be more potent at the
5-HT7 receptor, however, with lower selectivity over the 5-HT1A
receptor. The exceedingly high efficacy of several compounds
in this series (e.g., 9d: pKi ) 9.42) showed that the saturated
carbocycle of tetrahydrobenzindoles23–27 is not indispensable
for the 5-HT7 receptor binding.
By keeping the spacer length (n ) 4) and the alkyl group at
position 3 (R1 ) Et) fixed, and by keeping the oxindole nitrogen
atom unsubstituted (R4 ) H), further derivatives have been
synthesized for the investigation of the role of various substitu-
tion patterns at the phenylpiperazine moiety (Table 4). The
In the following experiments, we inquired into the influence
of various substituents (R1 ) H, Et, i-Bu) at position 3 on 5-HT7
receptor affinity (Table 3). Thus, an answer was sought to the
question of how the replacement of the third ring of the
tetrahydrobenzindole derivatives (e.g., 1-4) by simple alkyl
groups or a hydrogen atom influence 5-HT7 receptor affinity. It
was demonstrated that the 3-ethyl derivatives (R1 ) Et)
exhibited a slightly more favorable binding profile than the
3-monosubstituted (R1 ) H) analogues. On the other hand,
several 3-monosubstituted derivatives (12c-e) were efficacious
in the conflict drinking test. Nevertheless, because of higher

(Phenylpiperazinyl-butyl)oxindoles as 5-HT7 Antagonists
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 8 2525
Table 4. Human Recombinant 5-HT7 and Rat 5-HT1A Receptor Affinities of Compounds 9: The Effects of Various Phenylpiperazine Basic Groups
5-HT1A % inhibitiona
conflict drinking
light-dark testa
MED (mg/kg ip)
a
compound
W, Z
5-HT7 Ki (nM)
10-7
M
10-8
M
testa MED (mg/kg ip)
9f
H
2.07
5.38
2.55
25.40
5.11
0.41
0.38
0.43
0.63
0.60
0.66
26
79
33
24
51
42
11
10
11
14
11
6
28
6
3
9
11
2
12
0
0
0
10
10
NDa
ND
ND
ND
ND
>10
>10
<1
9g
9k
9l
9m
9b
9d
9n
9o
9p
9q
2′-MeO
3′-MeO
4′-MeO
2′-Cl
3′-Cl
4′-Cl
>20
>20
>20
>20
10
4′-F
10
3′,4′-di-Cl
3′-Cl-4′-F
3′-Cl-4′-Me
>20
>20
>20
ND
ND
ND
a See Table 1 for details.
Table 5. Human Recombinant 5-HT7 and Rat 5-HT1A Receptor
Affinities of Compounds 9: The Effects of Other Basic Groups
In addition to phenylpiperazine-type basic groups, some
piperidine derivatives have also been investigated (Table 5),
which facilitated 5-HT7 receptor binding previously in other
laboratories. Halophenyl-1,2,3,6-tetrahydropyridines (9r, 9s),27
4-fluorophenylpiperidine (9t), tetrahydrothienopyridine (9u),26
and tetrahydroisoquinoline (9v)26 have proved to be efficient
in our hands as well. The omission of the aromatic ring at this
position and its replacement by a methyl group (9w)16 resulted
in a significant reduction in the 5-HT7 affinity in accordance
with former results.21,24,38,41 Nonetheless, the increased rigidity
of the structure, caused by fused rings (9u, 9v) or the extension
of the conjugated π-electron system (9r, 9s), which led to an
enhanced potency among the tetrahydrobenzindoles,25,26 was
not superior to simple phenylpiperazines in our case.
With the above information in hand, 3- and 4-chlorophe-
nylpiperazine moieties were used in the studies to evaluate the
effect of further substitution patterns at the oxindole benzene
ring on the receptor binding. The introduction of halogen
substituents at the oxindole carbocycle (Table 6) was expected
to maintain 5-HT7 receptor affinity and at the same time to
increase the in vitro metabolic stability in rats, which was not
satisfactory in the case of the unsubstituted analogues (e.g., 9b:
4%, 9d: 9%). Indeed, several substituted derivatives demon-
strated improved stability: e.g. 12b: 40%, 9h′: 76%.
a See Table 1 for details. b See Table 1 for details. c See Table 1 for
details. d See Table 1 for details.
introduction of a methoxy substituent at position 2 (9g) leads
to high 5-HT7 receptor affinity, as described for other 5-HT7
ligands containing a 2-methoxyphenylpiperazine (2-MPP) unit.38
Nevertheless, 9g exhibits a strong 5-HT1A binding as well. A
shift of the methoxy group from position 2 to position 3 resulted
in a promising derivative (9 h), although 3-methoxyphenylpip-
erazine was described in the literature as a basic group leading
to poor 5-HT7 receptor binding.39 The introduction of a
(4-methoxyphenyl)piperazine moiety (9l) was detrimental to
5-HT7 receptor affinity. This tendency is in perfect accordance
with previous findings.19,25 On the other hand, contrary to
literature data,25 we have found that not only the monosubsti-
tuted derivatives (e.g., 9b, 9d) but also some disubstituted
analogues (9o, 9p) exhibited high 5-HT7 receptor binding
potency in this series. Para-halogenated phenylpiperazine de-
rivatives (9d, 9n) showed very strong 5-HT7 receptor affinity
and good activity in vivo. In summary, phenylpiperazines
bearing a substituent at the meta or para position were superior
to the ortho-substituted analogues, which was not the case in a
structurally related family of compounds, described recently.40
Among the several compounds exhibiting high 5-HT7 receptor
affinity, combined with good selectivity over the 5-HT1A
receptor, 9e′, 12d, and 12e were selected for further evaluation.
The detailed study showed that 9e′ had high selectivity over a
series of other receptors (Table 7). Despite the strong 5-HT7
receptor binding, 9e′ was inactive in both anxiolytic tests.
Nevertheless, 12d and 12e exhibited lower 5-HT7 affinities, but
demonstrated outstanding in vivo activity. The remarkable
anxiolytic potency observed for 12d and 12e may be due to a
multireceptorial action involving not only 5-HT7 but also 5-HT2A
receptor and R1 adrenoceptor. In fact, several lines of evidence
suggest the importance of these receptors or their interaction in
the mediation of anxiety.42,43 Receptor binding affinities of 9e′,
12d, and 12e were also determined on R2- and ꢀ-adrenoceptors
and other G-protein coupled receptors, however, these com-
pounds exhibited only unsubstantially low displacement when
applied in a concentration of 1 µmol/L.
The effects of 9 EGIS compounds, including 9e′, 12d, and
12e, on the intracellular cAMP levels have been studied in CHO
cells stably expressing the human 5-HT7A receptor. The drugs

2526 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 8
Volk et al.
Table 6. Human Recombinant 5-HT7 and Rat 5-HT1A Receptor Affinities of Compounds 9: The Effects of Various Substitution Patterns on the
Oxindole Carbocycle
5-HT1A % inhibitiona
conflict drinking
light-dark testa
MED (mg/kg ip)
a
compound
X
Y
W
5-HT7 Ki (nM)
10-7
M
10-8
M
testa MED (mg/kg ip)
9x
9y
9z
5-Cl
6-F
5-Cl
5-F
5-Cl
5-F
5-Cl
6-F
H
H
6-F
7-Cl
7-Cl
H
H
H
6-F
7-Cl
7-Cl
3′-Cl
3′-Cl
3′-Cl
3′-Cl
3′-Cl
4′-Cl
4′-Cl
4′-Cl
4′-Cl
4′-Cl
4′-Cl
8.27
0.67
9.07
4.75
9.46
2.81
3.72
0.79
6.99
5.97
10.13
18
37
16
31
7
9
0
9
0
NDa
11
>20
>20
20
>20
>20
>20
>20
>20
ND
ND
ND
ND
>10
ND
>10
ND
>10
ND
ND
<1
ND
ND
ND
ND
ND
0
ND
ND
ND
9a′
9b′
9c′
9d′
9e′
9f′
9g′
9h′
5-Cl
5-F
5-Cl
0
5
>20
<5
a See Table 1 for details.
Table 7. Receptor Binding Profile and Anxiolytic Effects of 9e′, 12d,
and 12e
Kia (nM) or MED (mg/kg ip)
receptor/in vivo test
9e′
12d
12e
5-HT1A
5-HT2A
1610
19.4
1800
17.5
150
55
5-HT2C
5-HT6
5-HT7
R1
D1
D2
358
186.5
690
580
7.0
42
2400
960
1500
1800
44
0.79
71.3
3360
950
>20
>10
20
1900
330
<10
>10
conflict drinking testa
light-dark testa
<2.5
<1
a See Table 1 for details.
were added at 10 nM or 1 µM concentrations in the presence
of 10 nM 5-CT, or at 1 µM in the absence of 5-CT and cAMP
levels, were measured. On its own, 10 nM 5-CT produced an
approximately 30-fold elevation in cAMP levels (Figure 2).
None of the compounds produced a significant change in the
cAMP levels at 1 µM concentration when they were incubated
in the absence of 5-CT. However, all EGIS compounds and
the reference SB-26997044 antagonized the effect of 10 nM
5-CT by more than 95%. The EGIS compounds behaved
differently when incubated at 10 nM concentration prior to
treatment with 10 nM 5-CT. At 10 nM concentration, SB-
269970 and 12c-d inhibited the 5-CT-induced elevation in
cAMP level by approximately 80%. 12e, 9e′, 9q, and 9b
inhibited cAMP level elevation by 40-65%, and 9c by 20%.
9j and 9r were ineffective. Overall, it can be stated that all the
compounds studied are antagonists at the human 5-HT7A
receptor, with the following order of potency: 12d ) 12c >
12e > 9e′ ≈ 9b > 9c > 9r ≈ 9j.
Figure 2. Effect of incubation with 1 µM EGIS compounds on cAMP
levels in uninduced CHO cells stably expressing the human 5-HT7A
receptor, and the effect of a preincubation with 1 µM or 10 nM EGIS
compounds on cAMP levels induced by an incubation with 10 nM
5-CT. The average cAMP level of control cells was 20 ( 8 fmol/µg
protein, the average cAMP level of cells induced by 10 nM 5-CT was
592 ( 232 fmol/µg protein (taken as 100%) in six independent
experiments. For methodological details, see Experimental Section.
receptors. While possessing an oxindole scaffold, the most
potent representatives can be considered long-chain arylpipera-
zines at the same time, which is a family of high importance
among 5-HT7 receptor–ligands.19,21,46–49 The 5-HT7 receptor
affinity of the compounds also made certain conclusions possible
in terms of structure-affinity relationships. Nonetheless, only
a limited correlation was found between the affinity of the
compounds for the 5-HT7 receptor and their in vivo activity.
Further studies on the enantiomeric separation and on more
detailed in vivo effects of the above compounds are in progress.
Conclusion
The present study describes the identification of new, potent
5-HT7 receptor–ligands, which contain an oxindole skeleton.
Besides the compounds presented here, more than 200 other
representatives of this family have also been synthesized.45 The
binding of these compounds to the 5-HT7 and 5-HT1A receptors
was measured, and their in vivo pharmacological activity was
studied in two anxiolytic tests. Several members of this family
proved to be highly potent 5-HT7 receptor antagonists (e.g., 9d:
pKi ) 9.42), some of them also with good selectivity over other
Experimental Section
Chemistry. All melting points were determined on a Büchi 535
capillary melting point apparatus and are uncorrected. IR spectra
were obtained on a Bruker IFS-113v FT spectrometer in KBr pellets.
1H and 13C NMR spectra were recorded in CDCl3 or DMSO-d6 on

(Phenylpiperazinyl-butyl)oxindoles as 5-HT7 Antagonists
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 8 2527
a Varian Unity Inova 400 (400 and 101 MHz for 1H and 13C NMR
7.4 Hz, CH3). 13C NMR (CDCl3, 101 MHz) δ: 179.9, 144.1, 131.9,
127.7, 122.6, 122.5, 107.8, 53.5, 44.5, 36.8, 32.7, 31.0, 25.6, 21.8,
8.5. Anal. (C15H20ClNO) C, H, N, Cl.
1
spectra, respectively) or 500 (500 and 125 MHz for H and 13C
NMR spectra, respectively) spectrometer using TMS as internal
standard. Chemical shifts (δ) and coupling constants (J) are given
in ppm and in Hz, respectively. Elemental analyses were performed
on a Perkin-Elmer 2400 analyzer. All reactions were followed by
General Procedure C: 5-Chlorination of 3-Alkyl-3-(ω-halo-
alkyl)oxindoles (7). The corresponding 3-alkyl-3-(ω-haloalkyl)ox-
indole (7, 5.0 mmol) was dissolved in glacial acetic acid (15 mL),
the solution was cooled to 16–18 °C, then the solution of sulfuryl
chloride (0.5 mL, 5.7 mmol) in glacial acetic acid (85 mL) was
added dropwise, maintaining the temperature below 20 °C. The
reaction mixture was stirred for a further 2 h at this temperature,
then it was poured onto ice under stirring. The white solid was
filtered, washed with water and hexane, and dried. The products
were used without further purification. Analytical samples were
obtained by recrystallization from the indicated solvents.
analytical thin layer chromatography (TLC) on silica gel 60 F254
.
Degussa’s activated Raney nickel catalyst in water was used in the
reactions.
General Procedure A: Preparation of 3-Alkyl-3-(ω-haloalkyl)-
oxindoles (7). To a mixture of n-BuLi in hexane (2.5 M, 200 mL,
0.50 mol) and THF (200 mL), the solution of the appropriate
3-alkyloxindole29 (6, 0.20 mol) in THF (250 mL) was added
dropwise at –78 °C, under argon atmosphere. Then the appropriate
R,ω-dihaloalkane (0.50 mol) was added dropwise, and the reaction
mixture was allowed to warm to room temperature. The stirring
was continued for 3 additional hours, the mixture was quenched
with ethanol (20 mL), and the solvents were evaporated. The residue
was taken up in ethyl acetate and extracted with water. The organic
layer was dried over Na2SO4 and evaporated. The oily residue
crystallized upon trituration with hexane (200 mL). The white solid
was filtered, washed with hexane, and dried. The products were
used without further purification. Analytical samples were obtained
by recrystallization from the indicated sovents.
3-(3-Chloropropyl)-3-ethyl-1,3-dihydro-2H-indol-2-one (7a).
The title compound was prepared according to the general procedure
A, starting from 3-ethyloxindole (6a) and 1-bromo-3-chloropropane.
Yield: 86%, mp 91–93 °C (hexane). IR (KBr): 3183, 1701, 751
cm-1. 1H NMR (CDCl3, 400 MHz): δ 9.15 (br, 1H, NH), 7.23 (dt,
1H, J ) 7.7, 1.3 Hz, H-6), 7.14 (d, 1H, J ) 6.8 Hz, H-4), 7.06 (dt,
1H, J ) 7.4, 0.9 Hz, H-5), 6.95 (d, 1H, J ) 7.7 Hz, H-7), 3.48–3.36
(m, 2H, CH2Cl), 2.02–1.93 (m, 3H), 1.85–1.78 (m, 1H), 1.66–1.54
(m, 1H), 1.44–1.30 (m, 1H), 0.65 (t, 3H, J ) 7.4 Hz, CH3). 13C
NMR (CDCl3, 101 MHz) δ: 182.6, 141.3, 132.0, 127.9, 123.0,
122.6, 109.8, 53.7, 44.8, 34.8, 31.0, 27.5, 8.5. Anal. (C13H16ClNO)
C, H, N, Cl.
5-Chloro-3-(4-chlorobutyl)-3-ethyl-1,3-dihydro-2H-indol-2-
one (8a). The title compound was prepared according to the general
procedure C, starting from 3-(4-chlorobutyl)-3-ethyloxindole (7b).
Yield: 86%, mp 116–117 °C (hexane-ethyl acetate). IR (KBr):
1
3285, 1717, 818 cm-1. H NMR (CDCl3, 400 MHz) δ: 8.72 (br,
1H, NH), 7.15 (dd, 1H, J ) 8.2, 2.1 Hz, H-6), 7.12 (d, 1H, J ) 2.1
Hz, H-4), 6.86 (d, 1H, J ) 8.2 Hz, H-7), 3.41 (t, 2H, J ) 6.7 Hz,
CH2Cl), 2.00–1.86 (m, 2H, CH2), 1.84–1.74 (m, 2H, CH2),
1.74–1.60 (m, 2H), 1.29–1.15 (m, 1H), 1.12–0.95 (m, 1H), 0.65 (t,
3H, J ) 7.4 Hz, CH3). 13C NMR (CDCl3, 101 MHz) δ: 182.0,
139.8, 134.2, 127.9, 127.8, 123.4, 110.7, 54.5, 44.4, 36.8, 32.5,
31.0, 21.7, 8.5. Anal. (C14H17Cl2NO) C, H, N, Cl.
5,7-Dichloro-3-(4-chlorobutyl)-3-ethyl-1,3-dihydro-2H-indol-
2-one (8c). 3-(4-Chlorobutyl)-3-ethyloxindole (7b, 10.06 g, 40
mmol) was dissolved in glacial acetic acid (80 mL). Sulfuryl
chloride (9.6 mL, 120 mmol) was added dropwise at ambient
temperature, then the solution was stirred at 60 °C for 3 h. The
reaction mixture was allowed to cool to room temperature, poured
onto ice, and extracted with diethyl ether. The organic layer was
extracted twice with 10% NaOH solution, dried over Na2SO4, and
evaporated. The residue crystallized upon treatment with hexane.
It was triturated in hexane, filtered, washed with hexane, and dried.
The product was used without further purification. An analytical
sample was obtained by recrystallization from hexane. Yield: 67%,
3-(4-Chlorobutyl)-3-ethyl-1,3-dihydro-2H-indol-2-one (7b).
The title compound was prepared according to the general procedure
A, starting from 3-ethyloxindole (6a) and 1-bromo-4-chlorobutane.
Yield: 94%, mp 104–105 °C (hexane-ethyl acetate). IR (KBr):
mp 65–67 °C (hexane). IR (KBr): 3165, 2964, 1713, 1455 cm-1
.
1H NMR (CDCl3, 400 MHz) δ: 8.38 (br, 1H, NH), 7.20 (d, 1H, J
) 1.9 Hz, H-6), 6.97 (d, 1H, J ) 1.8 Hz, H-4), 3.38 (t, 2H, J )
6.7 Hz, CH2Cl), 1.95–1.84 (m, 2H, CH2), 1.76–1.60 (m, 4H, 2 ×
CH2), 1.19–1.16 (m, 1H), 1.04–0.96 (m, 1H), 0.62 (t, 3H, J ) 7.4
Hz, CH3). 13C NMR (CDCl3, 101 MHz) δ: 180.5, 137.7, 135.1,
128.3, 127.6, 121.9, 115.7, 55.7, 44.3, 36.8, 32.5, 31.0, 21.7, 8.5.
Anal. (C14H16Cl3NO) C, H, N, Cl.
1
3181, 2941, 1700, 1306, 755 cm-1. H NMR (CDCl3, 400 MHz)
δ: 8.57 (br, 1H, NH), 7.21 (dt, 1H, J ) 7.6, 1.5 Hz, H-6), 7.12 (d,
1H, J ) 7.4 Hz, H-4), 7.06 (dt, 1H, J ) 7.5, 1.0 Hz, H-5), 6.92 (d,
1H, J ) 7.7 Hz, H-7), 3.39 (t, 2H, J ) 6.7 Hz, CH2Cl), 1.96–1.84
(m, 2H, CH2), 1.83–1.74 (m, 2H, CH2), 1.74–1.60 (m, 2H, CH2),
1.24–1.18 (m, 1H), 1.08–1.03 (m, 1H), 0.64 (t, 3H, J ) 7.4 Hz,
CH3). 13C NMR (CDCl3, 101 MHz) δ: 182.4, 141.2, 132.3, 127.7,
123.0, 122.5, 109.6, 54.1, 44.4, 36.8, 32.7, 31.0, 21.8, 8.5. Anal.
(C14H18ClNO) C, H, N, Cl.
General Procedure B: 1-Alkylation of 3-(4-Chlorobutyl)-3-
ethyloxindole (7b). NaH (55% suspension; 0.79 g, 18.0 mmol) was
suspended in DMF (20 mL) under argon atmosphere. To the ice-
cooled suspension, the solution of 3-(4-chlorobutyl)-3-ethyloxindole
(7b, 3.78 g, 15.0 mmol) in DMF (15 mL) was added dropwise
over a period of 15 min. Then the solution of the alkylating agent
(methyl iodide or benzyl chloride, 18.0 mmol) was added dropwise.
After the addition, the solution was allowed to room temperature,
stirred for 1 h, and poured onto ice. After extraction with diethyl
ether (30 mL), the organic layer was washed with water (30 mL),
dried over Na2SO4, and evaporated. The white crystalline com-
pounds were used without further purification. Analytical samples
were obtained after a recrystallization from hexane.
General Procedure D: Mesylation of 3-(4-Hydroxybutyl)ox-
indoles (10). The corresponding 3-(4-hydroxybutyl)oxindole28,29
(10, 55 mmol) was dissolved in THF (150 mL). Triethyl amine
(15.2 mL, 110 mmol) was added, and the solution was cooled to
–78 °C. Methanesulfonyl chloride (8.5 mL, 110 mmol) was added
dropwise. After the addition, the reaction mixture was allowed to
warm to room temperature and stirred for further 1 h. The white
precipitate was filtered off, and the filtrate was evaporated. The
residual oil was dissolved in ethyl acetate and extracted with 10
wt % aqueous hydrochloric acid until pH ) 5. The organic layer
was dried over Na2SO4 and evaporated. The brown oily residue
crystallized upon treatment with diisopropyl ether. It was triturated
with diisopropyl ether (100 mL), filtered, washed with hexane, and
dried. The beige solid was recrystallized from the indicated solvent,
resulting in white crystals.
3-(4-Chlorobutyl)-3-ethyl-1-methyl-1,3-dihydro-2H-indol-2-
one (13a). The title compound was prepared according to the
general procedure B, starting from 3-(4-chlorobutyl)-3-ethyloxindole
(7b) and methyl iodide. Yield: 76%, mp 62–63 °C (hexane). IR
(KBr): 3385, 2959, 1700, 763 cm-1. 1H NMR (CDCl3, 400 MHz)
δ: 7.28 (dt, 1H, J ) 7.7, 1.3 Hz, H-6), 7.14 (dd, 1H, J ) 7.3, 0.8
Hz, H-4), 7.08 (dt, 1H, J ) 7.5, 0.9 Hz, H-5), 6.86 (d, 1H, J ) 7.8
Hz, H-7), 3.38 (m, 2H, CH2Cl), 1.91 (m, 2H, CH2), 1.76 (m, 2H,
CH2), 1.64 (m, 2H), 1.09 (m, 1H), 0.99 (m, 1H), 0.55 (t, 3H, J )
Methanesulfonic acid 4-(2-oxo-2,3-dihydro-1H-indol-3-yl)-
butyl ester (11a). The title compound was prepared according to
the general procedure D, starting from 3-(4-hydroxybutyl)oxindole
(10a). Yield: 93%, mp 84–85 °C (heptane-ethyl acetate). IR (KBr):
1
3180, 1705 cm-1. H NMR (CDCl3, 400 MHz) δ: 9.33 (1H, s),
7.22 (1H, d, J ) 7.1 Hz), 7.21 (1H, t, J ) 7.0 Hz), 7.03 (1H, t, J
) 7.5 Hz), 6.93 (1H, d, J ) 7.6 Hz), 4.19 (2H, t, J ) 6.5 Hz), 3.49
(1H, t, J ) 6.0 Hz), 2.97 (3H, s), 2.05–1.98 (2H, m), 1.82–1.72
(2H, m) 1.58–1.40 (2H, m). 13C NMR (CDCl3, 101 MHz) δ: 180.5,

2528 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 8
Volk et al.
141.6, 129.1, 127.9, 123.9, 122.3, 109.9, 69.5, 45.7, 37.2, 29.6,
28.9, 21.6. Anal. (C13H17NO4S) C, H, N, S.
134.1, 132.4, 130.7, 127.7, 123.1, 121.6, 119.1, 115.2, 114.2, 109.3,
55.9, 53.2, 50.9, 45.6, 36.9, 30.5, 26.6, 23.8, 23.6, 8.6. Anal.
(C27H34ClN3O5) C: calcd, 62.84; found, 62.43; H, N, Cl.
General Procedure E: Coupling Reaction of the 3-Alkyl-3-
(ω-haloalkyl)oxindole Intermediates (7, 8) or 1,3-Dialkyl-3-(ω-
haloalkyl)oxindole Intermediates (13) with the Appropriate
Secondary Amines. The melt of the secondary amine (12 mmol)
was heated to 180 °C under slow stirring. The appropriate 3-alkyl-
3-(ω-haloalkyl)oxindole (7, 8, or 13; 12 mmol) and sodium
carbonate (1.36 g, 12 mmol) were added. After 1 h reaction time,
the brown melt was cooled to ambient temperature. Ethyl acetate
and water were added, and the layers were separated. The organic
layer was dried over MgSO4 and evaporated. The residual oil or
solid was purified by column chromatography using ethyl acetate
as eluent.
General Procedure E/1. In case the product of the chromato-
graphic purification crystallized upon treatment with diethyl ether,
it was triturated in this solvent, filtered, and the solid was
recrystallized from the solvent indicated below and dried to give a
white crystalline product.
General Procedure E/2. In case the product of the chromato-
graphic purification did not crystallize upon treatment with diethyl
ether, it was dissolved in diethyl ether (200 mL), the solid residue
was removed by filtration, and a calculated amount (1 equiv) of
hydrogen chloride (saturated solution of HCl gas in diethyl ether)
was added dropwise, under vigorous stirring. The white precipitate
was filtered, washed with diethyl ether and hexane, and dried in
vacuo at ambient temperature for 3 h. Where indicated, the obtained
hydrochloric salt was recrystallized.
General Procedure E/3. In case the product of the chromato-
graphic purification did not crystallize upon treatment with diethyl
ether and it did not give a crystalline hydrochloric acid salt in diethyl
ether, it was dissolved in ethyl acetate (100 mL) at 60–65 °C and
the solution of oxalic acid dihydrate (1 equiv) in ethyl acetate (50
mL) was added dropwise, keeping the temperature at 60–65 °C
during the addition. After the addition, the suspension was cooled
to ambient temperature, the white oxalic acid salt was filtered,
washed with ethyl acetate, and dried.
3-{4-[4-(4-Chlorophenyl)-piperazin-1-yl]-butyl}-3-ethyl-1,3-di-
hydro-2H-indol-2-one (9d). The title compound was prepared
according to the general procedure E/1, starting from 3-(4-
chlorobutyl)-3-ethyloxindole (7b) and 1-(4-chlorophenyl)-pipera-
zine. Yield: 88%, mp 145–146 °C (hexane-ethyl acetate). IR (KBr):
1
3163, 1712 cm-1. H NMR (CDCl3, 400 MHz) δ: 7.92 (1H, s),
7.20 (1H, dt, J ) 1.4, 7.6 Hz), 7.18 (2H, d, J ) 9.2 Hz), 7.12 (1H,
dt, J ) 0.7, 7.4 Hz), 7.05 (1H, dt, J ) 1.0, 7.5 Hz), 6.88 (1H, dt,
J ) 0.7, 7.7 Hz), 6.80 (2H, d, J ) 9.0 Hz), 3.10 (4H, t, J ) 5.0
Hz), 2.49 (4H, t, J ) 5.0 Hz), 2.24 (2H, t, J ) 7.8 Hz), 1.96–1.73
(4H, m), 1.50–1.36 (2H, m), 1.18–1.06 (1H, m), 0.98–0.84 (1H,
m), 0.63 (3H, t, J ) 7.4 Hz). 13C NMR (CDCl3, 101 MHz) δ:
182.6, 149.9, 141.3, 132.6, 128.9, 127.6, 124.4, 123.0, 122.3, 117.1,
109.5, 58.1, 54.2, 52.9, 49.0, 37.5, 31.0, 26.9, 22.2, 8.5. Anal.
(C24H30ClN3O). C: calcd, 69.97; found, 69.49; H, N, Cl.
3-{5-[4-(4-Chlorophenyl)-piperazin-1-yl]-pentyl}-3-ethyl-1,3-
dihydro-2H-indol-2-one (9e). The title compound was prepared
according to the general procedure E/1, starting from 3-(5-
bromopentyl)-3-ethyloxindole (7f) and 1-(4-chlorophenyl)-pipera-
zine. Yield: 61%, mp 143–144 °C (hexane-ethyl acetate). IR (KBr):
2939, 1700, 1497, 1236 cm-1. 1H NMR (DMSO-d6, 500 MHz) δ:
10.32 (1H, s), 7.22–7.14 (4H, m), 6.99–6.96 (1H, m), 6.92–6.89
(2H, m), 6.83 (1H, d, J ) 7.7 Hz), 3.06 (4H, t, J ) 4.9 Hz), 2.39
(4H, t, J ) 4.8 Hz), 2.16 (2H, t, J ) 7.3 Hz), 1.74–1.67 (4H, m),
1.31–1.27 (2H, m), 1.16–1.11 (2H, m), 0.97–0.94 (1H, m),
0.81–0.78 (1H, m), 0.50 (3H, t, J ) 7.4 Hz). 13C NMR (DMSO-
d6, 125 MHz) δ: 181.0, 150.0, 142.6, 132.5, 128.7, 127.6, 123.1,
122.3, 121.6, 116.8, 109.2, 57.8, 53.3, 52.7, 48.1, 37.1, 30.5, 27.3,
26.1, 23.9, 8.6. Anal. (C25H32ClN3O) C, H, N, Cl.
3-[4-(4-Phenylpiperazin-1-yl)-butyl]-3-ethyl-1,3-dihydro-2H-
indol-2-one oxalate (9f). The title compound was prepared
according to the general procedure E/3, starting from 3-(4-
chlorobutyl)-3-ethyloxindole (7b) and 1-phenyl-piperazine. Yield:
71%, mp 121–123 °C. IR (KBr): 3245, 1710, 1620 cm-1. 1H NMR
(DMSO-d6, 400 MHz) δ: 10.77 (2H, br), 10.46 (1H, s), 7.30–7.16
(4H, m), 7.02–6.91 (3H, m), 6.89 (1H, d, J ) 7.7 Hz), 6.84 (1H,
t, J ) 7.3 Hz), 3.37 (4H, br), 3.20 (4H, br), 2.93, 2.90 (2H, d, J )
6.0 Hz), 2.00–1.72 (4H, m), 1.56 (2H, m), 0.98 (1H, m), 0.83 (1H,
m), 0.51 (3H, t, J ) 7.3 Hz). 13C NMR (DMSO-d6, 101 MHz) δ:
180.9, 149.9, 142.7, 132.2, 129.3, 127.6, 123.2, 121.8, 120.1, 116.1,
109.4, 55.4, 53.2, 50.8, 45.7, 36.8, 30.4, 23.5, 21.5, 8.6. Anal.
(C26H33N3O5) C: calcd, 66.79; found, 66.29; H, N.
3-{4-[4-(3-Chlorophenyl)-piperazin-1-yl]-butyl}-3-ethyl-1,3-di-
hydro-2H-indol-2-one-H2O-HCl-Isopropyl Alcohol (1:1:1:1)
(9b). The coupling reaction was carried out according to the general
procedure E, starting from 3-(4-chlorobutyl)-3-ethyloxindole (7b)
and 1-(3,4-dichlorophenyl)-piperazine. After cooling the reaction
mixture to room temperature, ethyl acetate and aqueous hydrochloric
acid (10 wt %, 50 mL) were added and the layers were separated.
The organic layer was dried over Na2SO4, evaporated, and the beige
solid was recrystallized from isopropyl alcohol; mp 109–111 °C
(isopropyl alcohol). IR (KBr): 1701, 1180 cm-1. 1H NMR (DMSO-
d6, 400 MHz) δ: 11.14 (1H, br), 10.44 (1H, s), 7.25 (1H, t, J ) 8.2
Hz), 7.22 (1H, d, J ) 7.9 Hz), 7.18 (1H, dt, J ) 1.2, 7.7 Hz), 7.03
(1H, t, J ) 2.1 Hz), 6.99 (1H, dt, J ) 0.9, 7.6 Hz), 6.94 (1H, dd,
J ) 1.9, 8.3 Hz), 6.86 (1H, d, J ) 7.8 Hz), 6.86 (1H, d, J ) 7.9
Hz), 4.37 (1H, br), 3.84 (2H, br), 3.83–3.75 (1H, m), 3.5–3.3 (4H,
br), 3.21 (2H, t), 3.10–2.85 (4H, m), 1–85–1.65 (4H, m), 1.65–1.55
(2H, m), 1.04 (2H, d, J ) 6.1 Hz), 1.01–0.94 (1H, m), 0.9–0.7
(1H, m), 0.51 (3H, t, J ) 7.3 Hz). 13C NMR (DMSO-d6, 101 MHz)
δ: 180.8, 151.0, 142.7, 134.1, 132.1, 130.8, 127.8, 123.2, 121.8,
119.3, 115.4, 114.3, 109.4, 62.2, 55.1, 53.2, 50.3, 44.9, 36.6, 30.3,
25.7, 23.2, 21.4, 8.6. Anal. (C27H41Cl2N3O3) C, H, N, Cl.
3-{5-[4-(3-Chlorophenyl)-piperazin-1-yl]-pentyl}-3-ethyl-1,3-
dihydro-2H-indol-2-one oxalate (9c). The title compound was
prepared according to the general procedure E/3, starting from 3-(5-
bromopentyl)-3-ethyloxindole (7f) and 1-(3-chlorophenyl)-pipera-
3-Ethyl-3-{4-[4-(2-methoxyphenyl)-piperazin-1-yl]-butyl}-1,3-
dihydro-2H-indol-2-one oxalate (9g). The title compound was
prepared according to the general procedure E/3, starting from 3-(4-
chlorobutyl)-3-ethyloxindole (7b) and 1-(2-methoxyphenyl)-pip-
erazine. Yield: 74%, mp 180–183 °C. IR (KBr): 3201, 1707 cm-1
.
1H NMR (DMSO-d6, 400 MHz) δ: 10.4 (1H, br), 9.10 (2H, m),
7.21 (1H, d, J ) 7.9 Hz), 7.18 (1H, dt, J ) 7.7, 1.1 Hz), 7.02–6.94
(3H, m), 6.91–6.87 (2H, m), 6.86 (1H, d, J ) 7.7 Hz), 3.78 (3H,
s), 3.15 (8H, br), 2.88 (2H, t, J ) 7.8 Hz), 1.78–1.68 (4H, m), 1.53
(2H, m), 0.99–0.94 (1H, m), 0.83–0.77 (1H, m), 0.51 (3H, t, J )
7.3 Hz). 13C NMR (DMSO-d6, 101 MHz) δ: 180.8, 164.6, 152.0,
142.7, 139.8, 132.2, 127.8, 123.5, 123.2, 121.7, 121.0, 118.4, 112.1,
109.3, 55.5, 55.5, 53.2, 51.4, 47.4, 36.6, 30.4, 23.7, 21.5, 8.6. Anal.
(C27H35N3O6) C, H, N.
3-{4-[4-(3-Chlorophenyl)-piperazin-1-yl]-butyl}-3-isobutyl-
1,3-dihydro-2H-indol-2-one hydrochloride (9j). The title com-
pound was prepared according to the general procedure E/2, starting
from 3-(4-chlorobutyl)-3-isobutyloxindole (7e) and 1-(3-chlorophe-
nyl)-piperazine. Yield: 32%, mp 214–216 °C. IR (KBr): 3166, 2411,
1701 cm-1. 1H NMR (DMSO-d6, 400 MHz) δ: 11.1 (1H, br), 10.4
(1H, s), 7.25 (1H, t, J ) 8.1 Hz), 7.22 (1H, d, J ) 7.7 Hz), 7.17
(1H, dt, J ) 1.2, 7.7 Hz), 7.03 (1H, t, J ) 2.1 Hz), 6.98 (1H, dt,
J ) 0.9, 7.5 Hz), 6.93 (1H, dd, J ) 1.9, 8.4 Hz), 6.86 (1H, dd, J
) 2.0, 7.8 Hz), 6.86 (1H, d, J ) 7.9 Hz), 3.44–3.35 (4H, m), 3.18
(2H, t, J ) 11.9 Hz), 2.94 (4H, br), 1.80–1.55 (6H, m), 1.25–1.15
(1H, m), 1.03–0.91 (1H, m), 0.79–0.72 (1H, m), 0.67 (3H, d, J )
zine. Yield: 57%, mp 127–129 °C. IR (KBr): 3187, 1705, 754 cm-1
.
1H NMR (DMSO-d6, 400 MHz) δ: 10.35 (1H, s), 8.8–7.4 (2H,
m), 7.24 (1H, dt, J ) 8.1 Hz), 7.20 (1H, d, J ) 7.6 Hz), 7.16 (1H,
dt, J ) 1.1, 7.7 Hz), 7.00 (1H, t, J ) 2.3 Hz), 6.98 (1H, dt, J )
0.9, 7.6 Hz), 6.93 (1H, dd, J ) 2.0, 8.4 Hz), 6.84 (2H, d, J ) 8.4
Hz), 3.38 (4H, br), 3.07 (4H, br), 2.81 (2H, t, J ) 7.9 Hz), 1.80–1.64
(4H, m), 1.50 (2H, quintet, J ) 7.5 Hz), 1.15 (2H, quintet, J ) 6.8
Hz), 1.04–0.90 (1H, m), 0.90–0.76 (1H, m), 0.50 (3H, t, J ) 7.4
Hz). 13C NMR (DMSO-d6, 101 MHz) δ: 180.9, 164.3, 151.3, 142.7,

(Phenylpiperazinyl-butyl)oxindoles as 5-HT7 Antagonists
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 8 2529
6.7 Hz), 0.56 (3H, d, J ) 6.7 Hz). 13C NMR (DMSO-d6, 101 MHz)
δ: 181.2, 151.0, 142.4, 134.1, 132.4, 130.8, 127.7, 123.5, 121.6,
119.3, 115.4, 114.3, 109.4, 55.0, 52.1, 50.3, 45.7, 44.9, 38.9, 25.7,
25.1, 24.2, 23.2, 20.8. Anal. (C26H35Cl2N3O) C: calcd, 65.54; found,
65.05; H, N, Cl: calcd, 14.88; found, 14.45.
Hz), 127.7, 123.2, 121.7, 115.4 (d, J ) 21.0 Hz), 109.4, 55.6, 53.2,
51.8, 38.2, 36.6, 30.4, 29.9, 23.4, 21.5, 8.6. Anal. (C
C, H, N, Cl.
25H32ClFN2O)
3-[4-(6,7-Dihydro-4H-thieno[3,2-c]pyridin-5-yl)-butyl]-3-ethyl-
1,3-dihydro-2H-indol-2-one hydrochloride (9u). The title com-
pound was prepared according to the general procedure E/2, starting
from 3-(4-chlorobutyl)-3-isobutyloxindole (7e) and 6,7-dihydro-
4H-thieno[3,2-c]pyridine. Yield: 57%, mp 143–144 °C. IR (KBr):
3-Ethyl-3-{4-[4-(4-fluorophenyl)-piperazin-1-yl]-butyl}-1,3-di-
hydro-2H-indol-2-one (9n). The title compound was prepared
according to the general procedure E/1, starting from 3-(4-
chlorobutyl)-3-ethyloxindole (7b) and 1-(4-fluoro-phenyl)-pipera-
zine. Yield: 66%, mp 118–119 °C (hexane-ethyl acetate). IR (KBr):
1
3427, 1706 cm-1. H NMR (DMSO-d6, 400 MHz) δ: 11.2 (1H,
br), 10.5 (1H, s), 7.48 (1H, d, J ) 5.1 Hz), 7.25 (1H, d, J ) 7.2
Hz), 7.21 (1H, dt, J ) 1.2, 7.6 Hz), 7.03 (1H, dt, J ) 1.0, 7.5 Hz),
6.91 (1H, d, J ) 5.3 Hz), 6.90 (1H, d, J ) 7.8 Hz), 4.37 (1H, br),
4.11 (1H, br), 3.63 (1H, br), 3.25 (1H, sz), 3.20 (1H, m), 3.07 (3H,
br), 1.83–1.72 (6H, m), 1.01 (1H, m), 0.85 (1H, m), 0.54 (3H, t, J
) 7.4 Hz). 13C NMR (DMSO-d6, 50 MHz) δ: 180.7, 142.7, 132.1,
131.5, 128.2, 127.7, 125.3, 123.2, 121.6, 109.3, 54.6, 53.1, 49.9,
49.0, 36.5, 30.3, 23.6, 21.7, 21.4, 8.5. Anal. (C21H27ClN2OS) C,
H, N, Cl, S.
1
3161, 1713 cm-1. H NMR (CDCl3, 400 MHz) δ: 9.06 (1H, s),
7.19 (1H, dt, J ) 1.3, 7.6 Hz), 7.11 (1H, d, J ) 6.6 Hz), 7.04 (1H,
dt, J ) 0.8, 7.5 Hz), 6.93 (2H, t, J ) 9.1 Hz), 6.90 (1H, d, J ) 8.0
Hz), 6.82 (2H, dd, J ) 4.7, 9.3 Hz), 3.06 (4H, t, J ) 4.9 Hz), 2.50
(4H, t, J ) 4.9 Hz), 2.24 (2H, t, J ) 7.8 Hz), 1.97–1.88 (2H, m),
1.84–1.74 (2H, m), 1.47–1.35 (2H, m), 1.14–1.10 (1H, m),
0.94–0.88 (1H, m), 0.63 (3H, t, J ) 7.4 Hz). 13C NMR (CDCl3,
101 MHz) δ: 182.8, 157.0 (d, J ) 238.8 Hz), 147.9 (d, J ) 1.9
Hz), 141.4, 132.6, 127.6, 123.0, 122.3, 117.6 (d, J ) 7.6 Hz), 115.4
(d, J ) 22.1 Hz), 109.5, 58.1, 54.2, 53.1, 50.0, 37.5, 31.0, 26.9,
22.2, 8.5. Anal. (C24H30FN3O) C, H, N.
3-{4-[4-(3-Chlorophenyl)-piperazin-1-yl]-butyl}-3-ethyl-6-
fluoro-1,3-dihydro-2H-indol-2-one (9y). The title compound was
prepared according to the general procedure E/1, starting from 3-(4-
chlorobutyl)-3-ethyl-6-fluorooxindole (7d) and 1-(3-chlorophenyl)-
piperazine. Yield: 81%, mp 116–117 °C (hexane-ethyl acetate).
IR (KBr): 3163, 1717 cm-1. 1H NMR (CDCl3, 400 MHz) δ: 9.34
(1H, s), 7.13 (1H, t, J ) 8.0 Hz), 7.03 (1H, dd, J ) 5.4, 8.1 Hz),
6.83 (1H, t. J ) 2.1 Hz), 6.78 (1H, ddd, 0.8, 1.9, 8.0 Hz), 6.76–6.70
(2H, m), 6.67 (1H, dd, J ) 2.3, 8.8 Hz), 3.13 (4H, t, J ) 5.0 Hz),
2.48 (4H, t, J ) 5.0 Hz), 2.24 (2H, t, J ) 7.8 Hz), 1.95–1.87 (2H,
m), 1.80–1.72 (2H, m), 1.50–1.34 (2H, m), 1.16–1.04 (1H, m),
0.98–0.84 (1H, m), 0.62 (3H, t, J ) 7.4 Hz). 13C NMR (CDCl3,
101 MHz) δ: 183.2, 162.4 (d, J ) 244.1 Hz), 152.2, 142.6 (d, J )
11.8 Hz), 134.8, 129.9, 127.8 (d, J ) 3.1 Hz), 123.8 (d, J ) 9.5
Hz), 119.1, 115.6, 113.7, 108.6 (d, J ) 22.1 Hz), 98.3 (d, J ) 26.7
Hz), 58.1, 53.9, 52.9, 48.5, 37.5, 31.0, 26.8, 22.2, 8.5. Anal.
(C24H29ClFN3O) C, H, N, Cl.
3-{4-[4-(3,4-Dichlorophenyl)-piperazin-1-yl]-butyl}-3-ethyl-
1,3-dihydro-2H-indol-2-one-H2O-HCl-Isopropyl Alcohol (1:
1:1:1) (9o). The coupling reaction was carried out according to
the general procedure E, starting from 3-(4-chlorobutyl)-3-ethy-
loxindole (7b) and 1-(3,4-dichlorophenyl)-piperazine. After cooling
the reaction mixture to room temperature, ethyl acetate, and aqueous
hydrochloric acid (10 wt %, 50 mL) were added and the layers
were separated. The organic layer was dried over MgSO4, evapo-
rated, and the beige solid was recrystallized from a mixture of ethyl
acetate and isopropyl alcohol. Yield: 67%, mp 224–226 °C (ethyl
1
acetate-isopropyl alcohol). IR (KBr): 3385, 1708, 946 cm-1. H
NMR (DMSO-d6, 400 MHz) δ: 11.1 (1H, br), 10.4 (1H, s), 7.44
(1H, d, J ) 9.0 Hz), 7.23–7.16 (3H, m), 7.02–6.97 (2H, m), 6.87
(1H, d, J ) 7.6 Hz), 4.38 (1H, br), 3.83 (2H, br), 3.78 (1H, m),
3.42 (2H, m), 3.21 (2H, m), 2.97–2.95 (4H, m), 1.82–1.62 (6H,
m), 1.04 (6H, d, J ) 6.1 Hz), 1.01–0.95 (1H, m), 0.81–0.77 (1H,
m), 0.51 (3H, t, J ) 7.3 Hz). 13C NMR (DMSO-d6, 101 MHz) δ:
180.8, 149.5, 142.7, 132.1, 131.8, 130.8, 127.8, 123.2, 121.7, 120.9,
117.1, 116.0, 109.4, 55.1, 53.2, 50.2, 44.9, 36.6, 30.3, 23.3, 21.4,
8.6. Anal. (C27H40Cl3N3O3) C: calcd, 57.81; found, 58.46; H, N,
Cl.
5-Chloro-3-{4-[4-(3-chlorophenyl)-piperazin-1-yl]-butyl}-3-
ethyl-6-fluoro-1,3-dihydro-2H-indol-2-one hydrochloride (9z).
The title compound was prepared according to the general procedure
E/2, starting from 5-chloro-3-(4-chlorobutyl)-3-ethyl-6-fluoroox-
indole (8b) and 1-(3-chlorophenyl)-piperazine. Yield: 53%, mp
237–239 °C. IR (KBr): 3133, 2446, 1710, 1150, 946 cm–1. 1H NMR
(DMSO-d6, 400 MHz) δ: 11.15 (1H, br), 10.79 (1H, s), 7.52 (1H,
d, J ) 7.4 Hz), 7.25 (1H, t, J ) 8.2 Hz), 7.03 (1H, t, J ) 2.0 Hz),
6.94 (1H, dd, J ) 2.0, 8.2 Hz), 6.90 (1H, d, J ) 9.4 Hz), 6.86 (1H,
dd, J ) 1.4, 7.8 Hz), 3.83 (2H, d, J ) 12.5 Hz), 3.48–3.42 (2H,
m), 3.20 (2H, t, J ) 11.8 Hz), 2.98 (4H, br), 1.87–1.63 (6H, m),
0.96–0.78 (2H, m), 0.51 (3H, t, J ) 7.3 Hz). 13C NMR (DMSO-
d6, 101 MHz) δ: 180.6, 156.9 (d, J ) 243.8 Hz), 151.0, 143.0 (d,
J ) 11.5 Hz), 134.1, 130.8, 129.4 (d, J ) 3.4 Hz), 125.1, 119.3,
115.4, 114.3, 111.7 (d, J ) 18.3 Hz), 99.0 (d, J ) 26.3 Hz), 55.0,
53.4, 50.3, 44.9, 36.4, 30.2, 23.2, 21.4, 8.5. Anal. (C24H29Cl3FN3O)
C: calcd, 57.55; found, 57.08; H, N, Cl: calcd, 21.23; found, 20,76.
3-Ethyl-3-{4-[4-(4-fluorophenyl)-1,2,3,6-tetrahydro-pyridin-
1-yl]-butyl}-1,3-dihydro-2H-indol-2-one hydrochloride (9s). The
title compound was prepared according to the general procedure
E/2, starting from 3-(4-chlorobutyl)-3-ethyloxindole (7b) and 4-(4-
fluoro-phenyl)-1,2,3,6-tetrahydropyridine. Yield: 44%, mp 108–111
1
°C. IR (KBr): 3426, 1705 cm-1. H NMR (DMSO-d6, 400 MHz)
δ: 10.9 (1H, br), 10.45 (1H, s), 7.52 (2H, m), 7.23–7.15 (4H, m),
7.00 (1H, dt, J ) 0.9, 7.5 Hz), 6.87 (1H, d, J ) 7.7 Hz), 6.12 (1H,
s), 3.80–2.86 (6H, m), 2.98 (2H, t, J ) 8.1 Hz), 1.83–1.64 (6H,
m), 1.02–0.94 (1H, m), 0.88–0.78 (1H, m), 0.51 (3H, t, J ) 7.4
Hz). 13C NMR (DMSO-d6, 400 MHz) δ: 180.8, 162.0 (d, J ) 244.9
Hz), 142.7, 134.9 (d, J ) 3.1 Hz), 133.3, 132.1, 127.8, 127.0 (d, J
) 8.0 Hz), 123.2, 121.7, 116.5, 115.5 (d, J ) 21.4 Hz), 109.3,
54.6, 53.2, 49.4, 48.0, 36.6, 30.4, 23.8, 23.6, 21.5, 8.6. Anal.
(C25H30ClFN2O) C, H, N, Cl.
3-{4-[4-(4-Chlorophenyl)-piperazin-1-yl]-butyl}-3-ethyl-6-
fluoro-1,3-dihydro-2H-indol-2-one (9e′). The title compound was
prepared according to the general procedure E/1, starting from 3-(4-
chlorobutyl)-3-ethyl-6-fluorooxindole (7d) and 1-(4-chlorophenyl)-
piperazine. Yield: 68%, mp 145–147 °C (hexane-ethyl acetate).
3-Ethyl-3-{4-[4-(4-fluorophenyl)-piperidin-1-yl]-butyl}-1,3-di-
hydro-2H-indol-2-one hydrochloride (9t). The title compound was
prepared according to the general procedure E/2, starting from 3-(4-
chlorobutyl)-3-ethyloxindole (7b) and 4-(4-fluorophenyl)-piperidine,
and the obtained hydrochloric salt was recrystallized from a mixture
of ethyl acetate and isopropyl alcohol. Yield: 40%, mp 199–201
°C (ethyl acetate-isopropyl alcohol). IR (KBr): 3123, 3086, 2510,
1698 cm-1. 1H NMR (DMSO-d6, 400 MHz) δ: 10.9 (1H, br), 10.49
(1H, s), 7.27–7.17 (4H, m), 7.15 (2H, t, J ) 8.9 Hz), 7.00 (1H, dt,
J ) 0.9, 7.6 Hz), 6.89 (1H, d, J ) 7.6 Hz), 3.43–3.35 (2H, m),
2.91–2.77 (5H, m), 2.10–1.63 (10H, m), 1.00–0.80 (2H, m), 0.51
(3H, t, J ) 7.3 Hz). 13C NMR (DMSO-d6, 100 MHz) δ: 180.8,
161.0 (d, J ) 241.9 Hz), 142.7, 140.6, 132.1, 128.5 (d, J ) 7.6
1
IR (KBr): 3284, 1716, 1088 cm-1. H NMR (CDCl3, 400 MHz)
δ: 8.28 (1H, s), 7.18 (2H, d, J ) 8.9 Hz), 7.04 (1H, dd, J ) 5.3,
8.2 Hz), 6.81 (2H, d, J ) 9.0 Hz), 6.75 (1H, ddd, J ) 2.4, 8.2, 9.7
Hz), 6.64 (1H, dd, J ) 2.4, 8.7 Hz), 3.11 (4H, t, J ) 5.0 Hz), 2.50
(4H, t, J ) 5.0 Hz), 2.25 (2H, t, J ) 7.8 Hz), 1.95–1.81 (2H, m),
1.80–1.71 (2H, m), 1.48–1.35 (2H, m), 1.12–1.04 (1H, m),
0.96–0.84 (1H, m), 0.63 (3H, t, J ) 7.4 Hz). 13C NMR (CDCl3,
101 MHz) δ: 182.6, 162.4 (d, J ) 244.2 Hz), 149.9, 142.4 (d, J )
11.4 Hz), 128.9, 127.8 (d, J ) 2.7 Hz), 124.4, 123.9 (d, J ) 9.9
Hz), 117.1, 108.7 (d, J ) 22.1 Hz), 98.2 (d, J ) 27.1 Hz), 58.1,
53.8, 53.0, 49.0, 37.6, 31.1, 26.9, 22.2, 8.5. Anal. (C24H29ClFN3O)
C, H, N, Cl.

2530 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 8
Volk et al.
5,7-Dichloro-3-{4-[4-(4-chlorophenyl)-piperazin-1-yl]-butyl}-
3-ethyl-1,3-dihydro-2H-indol-2-one (9h′). The title compound was
prepared according to the general procedure E/1 starting from 5,7-
dichloro-3-(4-chlorobutyl)-3-ethyloxindole (8c) and 1-(4-chlorophe-
nyl)-piperazine. Yield: 60%, mp 152–154 °C (heptane-ethyl
in a humidified atmosphere with 5% CO2. Cells were seeded at
30000 cells per well in a 96-well plate 24 h before treatment with
compounds.
Compound Preparation and Treatment. The compounds were
dissolved in DMSO at a concentration of 1 mM. The final
concentration of DMSO in the experiments was 0.1% (v/v). In the
absence of 5-CT, the cells were incubated with 1 µM or 10 nM
compounds for 20 min at 37 °C in order to investigate their effect
on the resting cAMP level. To examine antagonist behavior, the
cells were preincubated with 1 µM or 10 nM compounds for 10
min, immediately before a 20 min incubation with 10 nM 5-CT at
37 °C.
cAMP Measurement. The cells were lysed and the cAMP levels
were detected using the BioTrak Direct cAMP EIA kit (Amersham).
Protein determination was made by the BCA assay (Sigma).
Radioligand Binding Assay and Data Analysis. In the case of
5-HT7 assays, we used cloned human serotonin receptor subtype 7
(h5-HT7) produced in CHO cells (PerkinElmer), following the
recommended assay conditions using [3H]LSD (NEN) as radioli-
gand. Nonspecific binding was determined in the presence of 25
µM clozapine (Sigma). Binding assays were terminated by filtration
over Whatman GF/C glass-fiber filter (presoaked in 0.3% polyeth-
ylenimine for 30 min) using a Brandel cell harvester, and bound
radioactivity was measured with a Packard TopCount scintillation
spectrometer.
1
acetate). IR (KBr): 3137, 1719, 826 cm-1. H NMR (CDCl3, 400
MHz) δ: 8.15 (1H, s), 7.23 (1H, d, J ) 1.8 Hz), 7.18 (2H, d, J )
9.1 Hz), 7.01 (1H, d, J ) 1.8 Hz), 6.81 (2H, d, J ) 9.1 Hz), 3.12
(4H, t, J ) 5.0 Hz), 2.51 (4H, t, J ) 5.0 Hz), 2.27 (2H, t, J ) 7.8
Hz), 1.98–1.88 (2H, m), 1.80–1.70 (2H, m), 1.50–1.36 (2H, m),
1.16–1.04 (1H, m), 0.98–0.86 (1H, m), 0.65 (3H, t, J ) 7.4 Hz).
13C NMR (CDCl3, 101 MHz) δ: 180.3, 149.9, 137.7, 135.3, 128.9,
128.2, 127.5, 124.4, 122.0, 117.1, 115.7, 57.9, 55.8, 53.0, 49.1,
37.5, 31.1, 26.7, 22.2, 8.5. Anal. (C24H28Cl3N3O) C, H, N, Cl.
General Procedure F: Coupling Reaction between the 3-[4-
(Methanesulfonyloxy)-butyl]oxindole Intermediates (11) and
the Appropriately Substituted 4-Phenylpiperazines. The melt of
the secondary amine (12 mmol) was heated to 120 °C under slow
stirring. The appropriate 3-[4-(methanesulfonyloxy)-butyl]oxindole
(11, 12 mmol) and sodium carbonate (1.36 g, 12 mmol) were added.
After 1 h reaction time, the brown melt was cooled to ambient
temperature. Ethyl acetate and water were added and the layers
were separated. The organic layer was dried over MgSO4 and
evaporated. The residual oil or solid was purified by column
chromatography using ethyl acetate as eluent.
5-HT1A receptor binding assays were performed according to the
method of Peroutka and Snyder50 with minor modifications. 5-HT1A
membrane was prepared from adult rat frontal cortex obtained
immediately following decapitation. The wet weight was measured
and the tissue was homogenized (Potter-Elvehjem) in 50 volumes
of 50 mM Tris-HCl buffer (pH 7.7 at 25 °C). The tissue homogenate
was centrifuged at 40000g for 15 min at 4 °C, and the pellet was
resuspended in the same volume of the above buffer. The
homogenate was incubated in a shaking water bath for 10 min at
37 °C. After a quick chilling on ice, the homogenate was centrifuged
(40000g, 15 min, 4 °C), resuspended, and centrifuged again
(40000g, 15 min, 4 °C). The membrane was finally resuspended in
30 volumes of 50 mM Tris-HCl buffer (pH 7.7). The incubation
buffer contained 50 mM Tris-HCl (pH 7.7), 6.66 mM CaCl2, 16.66
µM pargyline, and 0.166% ascorbic acid. 5-HT1A sites were labeled
with 1.5 nM [3H]8-OH-DPAT (Amersham). Nonspecific binding
was determined in the presence of 10 µM 5-hydroxytryptamine
creatinine sulfate complex (5-HT, Sigma). The samples were
incubated for 45 min at 25 °C. Following the incubation, the
samples were rapidly filtered over Whatman GF/B glass fiber filter
(presoaked in 0.05% polyethylenimine for 30 min) and washed.
Individual filters were inserted into vials, equilibrated for 6 h with
Opti-Fluor scintillation fluid (PerkinElmer), and counted with a
Packard TopCount scintillation spectrometer.
General Procedure F/1. In case the product of the chromato-
graphic purification crystallized upon treatment with diethyl ether,
it was triturated in this solvent, filtered, and the solid was
recrystallized from the solvent indicated below and dried to give a
white crystalline product.
General Procedure F/2. In case the product of the chromato-
graphic purification did not crystallize upon treatment with diethyl
ether, it was dissolved in diethyl ether (200 mL), the solid residue
was removed by filtration, and a calculated amount (1 equiv) of
hydrogen chloride (saturated solution of HCl gas in diethyl ether)
was added dropwise, under vigorous stirring. The white precipitate
was filtered, washed with diethyl ether and hexane, and dried in
vacuo at ambient temperature for 3 h.
3-{4-[4-(4-Chloro-phenyl)-piperazin-1-yl]-butyl}-1,3-dihydro-
2H-indol-2-one (12d). The title compound was prepared according
to the general procedure F/1, starting from 3-[4-(methanesulfony-
loxy)-butyl]oxindole (11a) and (4-chlorophenyl)-piperazine. Yield:
74%, mp 135–136 °C (hexane-ethyl acetate). IR (KBR): 3203,
1718, 754 cm-1. 1H NMR (CDCl3, TMS, 400 MHz) δ: 8.60 (1H,
s), 7.24–7.15 (2H, m), 7.18 (2H, d, J ) 9.1 Hz), 7.02 (1H, dt, J )
0.9, 7.6 Hz), 6.88 (1H, d, J ) 7.7 Hz), 6.81 (2H, d, J ) 9.2 Hz),
3.48 (1H, t, J ) 6.0 Hz), 3.13 (4H, t, J ) 5.0 Hz), 2.55 (4H, t, J
) 5.0 Hz), 2.36 (2H, t, J ) 7.5 Hz), 2.05–1.96 (2H, m), 1.58–1.36
(4H, m). 13C NMR (CDCl3, 101 MHz) δ: 180.3, 149.9, 141.5,
129.7, 128.9, 127.8, 124.4, 124.1, 122.2, 117.1, 109.6, 58.2, 53.0,
49.1, 45.9, 30.3, 26.8, 23.7. Anal. (C22H26ClN3O) C, H, N, Cl.
Membranes, radioligands, and varying concentrations of com-
petitive ligands were incubated in triplicates. Competition binding
data were fit to a single-site binding model using Prism GraphPad
for Ki determination. Ki values were calculated from two displace-
ment curves (nine concentrations) in triplicate.
5-Fluoro-3-[4-(4-phenyl-piperazin-1-il)-butyl]-1,3-dihydro-
2H-indol-2-one (12e). The title compound was prepared according
to the general procedure F/1, starting from 5-fluoro-3-[4-(meth-
anesulfonyloxy)-butyl]oxindole (11b) and phenylpiperazine. Yield:
61%, mp 142–144 °C (hexane-ethyl acetate). IR (KBr): 3188, 1705
Conflict Drinking (Vogel) Test. Experiments were performed
in a computer-operated system (LIIKOSYS, Experimetria, Hungary)
consisting of 8 test chambers (20 cm × 20 cm × 20 cm Plexiglas
boxes), each of which was equipped with a drinking spout mounted
at appropriate height on the wall of the chamber and a metal grid
floor for delivering electric shocks. Male Wistar rats, weighing
160–180 g, were deprived of drinking water for 48 h and fasted
for 24 h prior to test. Test and reference compounds or vehicle
were administered ip 30 min prior to test. All procedures were
carried out in a quiet, air-conditioned room between 07:30 and 13:
00 h at an ambient temperature of 23 °C. At the beginning of the
experiment, the animals were placed in the test chamber where they
had free access to drinking water for a 30 s grace period. After
that, electric shocks (600 µA, 0.6 s) were applied through the
drinking spout following every 20 licks during a 5 min test period.36
Number of punished licks was recorded and stored in a computer.
Means ( SEM of numbers of tolerated shocks were calculated in
1
cm-1. H NMR (CDCl3, TMS, 400 MHz) δ: 9.52 (1H, s), 7.24
(2H, dd, J ) 7.3, 8.8 Hz), 6.97 (1H, dd, J ) 1.8, 8.1 Hz), 6.92–6.87
(3H, m), 6.84 (1H, t, J ) 7.3 Hz), 6.80 (1H, dd, J ) 4.3, 8.4 Hz),
3.47 (1H, t, J ) 6.0 Hz), 3.17 (4H, t, J ) 5.0 Hz), 2.57 (4H, t, J
) 5.0 Hz), 2.36 (2H, t, J ) 7.7 Hz), 1.99–1.95 (2H, m), 1.57–1.52
(2H, m), 1.45–1.34 (2H, m). 13C NMR (CDCl3, TMS, 125 MHz)
δ: 180.7, 158.9, 151.2, 137.6 (d, J ) 2.1 Hz), 131.2 (d, J ) 8.1
Hz), 129.0, 119.6, 115.9, 114.1 (d, J ) 23.5 Hz), 112.0 (d, J )
24.8 Hz), 110.1 (d, J ) 8.1 Hz), 58.1, 53.1, 49.0, 46.5 (d, J ) 1.7
Hz), 30.2, 26.6, 23.6. Anal. (C22H26FN3O) C, H, N.
Pharmacology. Cell Culture. CHO cells stably expressing the
5-HT7A receptor were cultured in 1:1 F12:DMEM (Sigma) supple-
mented with 1% (v/v) penicillin-streptomycin (Sigma), 5% fetal
calf serum (Gibco BRL), and 2 mM L-glutamine (Sigma) at 37 °C

(Phenylpiperazinyl-butyl)oxindoles as 5-HT7 Antagonists
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 8 2531
(14) Linnanen, T.; Brisander, M.; Unelius, L.; Rosqvist, S.; Nordvall, G.;
Hacksell, U.; Johansson, A. M. Atropisomeric derivatives of 2′,6′-
disubstituted (R)-11-phenylaporphine: selective serotonin 5-HT7 recep-
tor antagonists. J. Med. Chem. 2001, 44, 1337–1340.
(15) Holmberg, P.; Sohn, D.; Leideborg, R.; Caldirola, P.; Zlatoidsky, P.;
Hanson, S.; Mohell, N.; Rosqvist, S.; Nordvall, G.; Johansson, A. M.;
Johansson, R. Novel 2-aminotetralin and 3-aminochroman derivatives
as selective serotonin 5-HT7 receptor agonists and antagonists. J. Med.
Chem. 2004, 47, 3927–3930.
(16) Forbes, I. T.; Douglas, S.; Gribble, A. D.; Ife, R. J.; Lightfoot, A. P.;
Garner, A. E.; Riley, G. J.; Jeffrey, P.; Stevens, A. J.; Stean, T. O.;
Thomas, D. R. SB-656104-A: a novel 5-HT7 receptor antagonist with
improved in vivo properties. Bioorg. Med. Chem. Lett. 2002, 12, 3341–
3344.
(17) Forbes, I. T.; Cooper, D. G.; Dodds, E. K.; Douglas, S. E.; Gribble,
A. D.; Ife, R. J.; Lightfoot, A. P.; Meeson, M.; Campbell, L. P.;
Coleman, T.; Riley, G. J.; Thomas, D. R. Identification of a novel
series of selective 5-HT7 receptor antagonists. Bioorg. Med. Chem.
Lett. 2003, 13, 1055–1058.
each group, statistical analysis of data was performed by one-way
ANOVA, followed by the Duncan’s test.
Light-Dark Test. Test was performed in a room illuminated
with a 2 lx light source. An animal activity monitor equipped with
six two-compartment automated test chambers (Omnitech, Digiscan,
model RXYZCM16) was used for all experiments. Each box
consisted of one dark and one lit compartment. Both areas measured
39 cm × 20 cm × 29 cm. Access between the two compartments
was provided by an 8 cm × 8 cm passage way. A 60 W white
tungsten light bulb was used to illuminate the lit area. Interruptions
of the 32 infrared beams (16 at 2 cm and 16 at 8 cm height above
the box floor) in both compartments were automatically recorded
by the Digiscan analyzer and transmitted to a computer. Male NMRI
mice, weighing 25–33 g, were used for the test. Mice were kept in
a dark room, treated ip 30 min prior to test, and were placed
individually in the center of the lit area. Behavioral activity was
detected for 5 min. Time spent in each area, number of transitions,
and horizontal and vertical activities were recorded.37 Means (
SEM values were calculated and the statistical analysis of data was
performed by one-way ANOVA, followed by the Duncan’s test.
(18) Mattson, R. J.; Denhart, D. J.; Catt, J. D.; Dee, M. F.; Deskus, J. A.;
Ditta, J. L.; Epperson, J.; King, H. D.; Gao, A.; Poss, M. A.; Purandare,
A.; Tortolani, D.; Zhao, Y.; Yang, H.; Yeola, S.; Palmer, J.; Torrente,
J.; Stark, A.; Johnson, G. Aminotriazine 5-HT7 antagonists. Bioorg.
Med. Chem. Lett. 2004, 14, 4245–4248.
(19) Leopoldo, M.; Berardi, F.; Colabufo, N. A.; Contino, M.; Lacivita,
E.; Niso, M.; Perrone, R.; Tortorella, V. Structure-affinity relationship
study on N-(1,2,3,4-tetrahydronaphthalen-1-yl)-4-aryl-1-piperazinealky-
lamides, a new class of 5-hydroxytryptamine7 receptor agents. J. Med.
Chem. 2004, 47, 6616–6624.
(20) Parikh, V.; Welch, W. M.; Schmidt, A. W. Discovery of a series of
(4,5-dihydroimidazol-2-yl)-biphenylamine 5-HT7 agonists. Bioorg.
Med. Chem. Lett. 2003, 13, 269–271.
(21) Perrone, R.; Berardi, F.; Colabufo, N. A.; Lacivita, E.; Leopoldo, M.;
Tortorella, V. Synthesis and structure-affinity relationships of 1-[ω-
(4-aryl-1-piperazinyl)alkyl]-1-aryl ketones as 5-HT7 receptor ligands.
J. Med. Chem. 2003, 46, 646–649.
(22) Holmberg, P.; Tedenborg, L.; Rosqvist, S.; Johansson, A. M. Novel
3-aminochromans as potential pharmacological tools for the serotonin
5-HT7 receptor. Bioorg. Med. Chem. Lett. 2005, 15, 747–750.
(23) Koyama, M.; Kikuchi, Ch.; Ushiroda, O.; Ando, T.; Nagaso, H.; Fuji,
K.; Okuno, M.; Hiranuma, T. Preparation of tetrahydrobenzindole
derivatives for the treatment or prevention of mental diseases. WO
9800400 (EP 937 715), 1997; Chem. Abstr. 1997, 128114961.
(24) Kikuchi, Ch.; Nagaso, H.; Hiranuma, T.; Koyama, M. Tetrahydroben-
zindoles: selective antagonists of the 5-HT7 receptor. J. Med. Chem.
1999, 42, 533–535.
(25) Kikuchi, Ch.; Ando, T.; Watanabe, T.; Nagaso, H.; Okuno, M.;
Hiranuma, T.; Koyama, M. 2a-[4-(tetrahydropyridoindol-2-yl)bu-
tyl]tetrahydrobenzindole derivatives: new selective antagonists of the
5-hydroxytryptamine7 receptor. J. Med. Chem. 2002, 45, 2197–2206.
(26) Kikuchi, Ch.; Hiranuma, T.; Koyama, M. Tetrahydrothienopyridyl-
butyltetrahydrobenzindoles: new selective ligands of the 5-HT7 recep-
tor. Bioorg. Med. Chem. Lett. 2002, 12, 2549–2552.
(27) Kikuchi, Ch.; Suzuki, H.; Hiranuma, T.; Koyama, M. New tetrahy-
drobenzindoles as potent and selective 5-HT7 antagonists with
increased in vitro metabolic stability. Bioorg. Med. Chem. Lett. 2003,
13, 61–64.
(28) Volk, B.; Mezei, T.; Simig, G. Raney nickel-induced 3-alkylation of
oxindole with alcohols and diols. Synthesis 2002, 595–597.
(29) Volk, B.; Simig, G. New one-pot synthesis of 3-alkyl- and 3-(ω-
hydroxyalkyl)oxindoles from isatins. Eur. J. Org. Chem. 2003, 3991–
3996.
Supporting Information Available: Elemental analysis data for
all new compounds, characterization and preparation of compounds
7c-f, 8b, 8d, 9a, 9h-i, 9k-m, 9p-r, 9v-x, 9a′-d′, 9f′-g′, 11b,
12a-c, 13b, 14a-b. This material is available free of charge via
the Internet at http://pubs.acs.org.
References
(1) Hoyer, D.; Hannon, J. P.; Martin, G. R. Molecular, pharmacological
and functional diversity of 5-HT receptors. Pharmacol., Biochem.
BehaV. 2002, 71, 533–554.
(2) Glennon, R. A. Higher-end serotonin receptors: 5-HT5, 5-HT6, and
5-HT7. J. Med. Chem. 2003, 46, 2795–2810.
(3) Roth, B. L.; Craigo, S. C.; Choudhary, M. S.; Uluer, A.; Monsma,
F. J., Jr.; Shen, Y.; Meltzer, H. Y.; Sibley, D. R. Binding of typical
and atypical antipsychotic agents to 5-hydroxytryptamine-6 and
5-hydroxytryptamine-7 receptors. J. Pharm. Exp. Ther. 1994, 268,
1403–1410.
(4) Mullins, U. L.; Gianutsos, G.; Eison, A. S. Effects of antidepressants
on 5-HT7 receptor regulation in the rat hypothalamus. Neuropsychop-
harmacology 1999, 21, 352–367.
(5) Clemett, D. A.; Kendall, D. A.; Cockett, M. I.; Marsden, C. A.; Fone,
K. C. F. Pindolol-insensitive [3H]-5-hydroxytryptamine binding in the
rat hypothalamus; identity with 5-hydroxytryptamine7 receptors. Br. J.
Pharmacol. 1999, 127, 236–242.
(6) Hagan, J. J.; Price, G. W.; Jeffrey, P.; Deeks, N. J.; Stean, T.; Piper,
D.; Smith, M. I.; Upton, N.; Medhurst, A. D.; Middlemiss, D. N.;
Riley, G. J.; Lovell, P. J.; Bromidge, S. M.; Thomas, D. R.
Characterization of SB-269970-A, a selective 5-HT7 receptor antago-
nist. Br. J. Pharmacol. 2000, 130, 539–548.
(7) Sleight, A. J.; Carolo, C.; Petit, N.; Zwingelstein, C.; Bourson, A.
Identification of 5-hydroxytryptamine7 receptor binding sites in rat
hypothalamus: sensitivity to chronic antidepressant treatment. Mol.
Pharmacol. 1995, 47, 99–103.
(8) Pouzet, B. SB-258741: a 5-HT7 receptor antagonist of potential clinical
interest. CNS Drug ReV. 2002, 8, 90–100.
(9) Terrón, J. A.; Falcón-Neri, A. Pharmacological evidence for the 5-HT7
receptor mediating smooth muscle relaxation in canine cerebral arteries.
Br. J. Pharmacol. 1999, 127, 609–616.
(30) Porcs-Makkay, M.; Volk, B.; Kapiller-Dezsöfi, R.; Mezei, T.; Simig,
G. New routes to oxindole derivatives. Monatsh. Chem. 2004, 135,
697–711.
(10) Terrón, J. A. Is the 5-HT7 receptor involved in the pathogenesis and
prophylactic treatment of migraine? Eur. J. Pharmacol. 2002, 439,
1–11.
(31) This difficulty is investigated in detail in Gruda, I. Formation des
dérivés N- et C-substitués au cours de l’alkylation de l’indol-2(3H)-
one. Can. J. Chem. 1972, 50, 18–23.
(11) Ying, S.-W.; Rusak, B. 5-HT7 receptors mediate serotonergic effects
on light-sensitive suprachiasmatic nucleus neurons. Brain Res. 1997,
755, 246–254.
(32) Reisch, J.; Müller, M.; Labitzke, H. Synthesewege zu 3-substituierten
Indol-2-onen Arch. Pharm. (Weinheim, Germany) 1984, 317, 639-646;
Chem. Abstr. 1984, 101, 130558c.
(12) Thomas, D. R.; Melotto, S.; Massagrande, M.; Gribble, A. D.; Jeffrey,
P.; Stevens, A. J.; Deeks, N. J.; Eddershaw, P. J.; Fenwick, S. H.;
Riley, G.; Stean, T.; Scott, C. M.; Hill, M. J.; Middlemiss, D. N.;
Hagan, J. J.; Price, G. W.; Forbes, I. T. SB-656104-A, a novel selective
5-HT7 receptor antagonist, modulates REM sleep in rats. Br. J.
Pharmacol. 2003, 139, 705–714.
(13) Lovell, P. J.; Bromidge, S. M.; Dabbs, S.; Duckworth, D. M.; Forbes,
I. T.; Jennings, A. J.; King, F. D.; Middlemiss, D. N.; Rahman, S. K.;
Saunder, D. V.; Collin, L. L.; Hagan, J. J.; Riley, G. J.; Thomas, D. R.
A novel, potent, and selective 5-HT7 antagonist: (R)-3-(2-(2-(4-
methylpiperidin-1-yl)ethyl)pyrrolidine-1-sulfonyl)phenol (SB-269970).
J. Med. Chem. 2000, 43, 342–345.
(33) Kende, A. S.; Hodges, J. C. Regioselective C-3 alkylations of oxindole
dianion. Synth. Commun. 1982, 12, 1–10.
(34) Popp, F. D. The chemistry of isatin. In AdVances in Heterocyclic
Chemistry, Vol. 18; Katritzky, A. R., Boulton, A. J., Eds.; Academic
Press: New York, 1975; pp 2–5,and references cited therein.
(35) Wilcox, R. E.; Ragan, J. E.; Pearlman, R. S.; Brusniak, M. Y.-K.;
Eglen, R. M.; Bonhaus, D. W.; Tenner, T. E., Jr.; Miller, J. D. High-
affinity interactions of ligands at recombinant guinea pig 5-HT7
receptors. J. Comput. Aided Mol. Des. 2001, 15, 883–909.
(36) Vogel, J. R.; Beer, B.; Clody, D. E. A simple and reliable conflict
procedure for testing antianxiety agents. Psychopharmacology (Berlin)
1971, 21, 1–7.

2532 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 8
Volk et al.
(37) Costall, B.; Jones, B. J.; Kelly, M. E.; Naylor, R. J.; Tomkins, D. M.
Exploration of mice in a black and white test box: validation as a
model of anxiety. Pharm. Biochem. BehaV. 1989, 32, 777–785.
(38) Paillet-Loilier, M.; Fabis, F.; Lepailleur, A.; Bureau, R.; Butt-Gueulle,
S.; Dauphin, F.; Delarue, C.; Vaudry, H.; Rault, S. Phenylpyrroles, a new
chemolibrary virtual screening class of 5-HT7 receptor ligands. Bioorg.
Med. Chem. Lett. 2005, 15, 3753–3757, and references cited herein.
(39) Bojarski, A. J.; Paluchowska, M. H.; Duszyn´ska, B.; Kłodzin´ska, A.;
Tatarczyn´ska, E.; Chojnacka-Woˇjcik, E. 1-Aryl-4-(4-succinimidobu-
tyl)piperazines and their conformationally constrained analogues:
synthesis, binding to serotonin (5-HT1A, 5-HT2A, 5-HT7), R1-adrenergic
and dopaminergic D2 receptors, and in vivo 5-HT1A functional
characteristics. Bioorg. Med. Chem. 2005, 13, 2293–2303.
(40) Leopoldo, M.; Lacivita, E.; Contino, M.; Colabufo, N. A.; Berardi,
F.; Perrone, R. Structure-activity relationship study of N-(1,2,3,4-
tetrahydronaphthalen-1-yl)-4-aryl-1-piperazinehexanamides, a class of
5-HT7 receptor agents. 2. J. Med. Chem. 2007, 50, 4214–4221.
(41) Raubo, P.; Beer, M. S.; Hunt, P. A.; Huscroft, I. T.; London, C.;
Stanton, J. A.; Kulagowski, J. J. Aminoalkyl phenyl sulfonessa novel
series of 5-HT7 receptor ligands. Bioorg. Med. Chem. Lett. 2006, 16,
1255–1258.
Preparation of pyridine derivatives of alkyl oxindoles as 5-HT7
receptor active agents. WO 2005108388, 2005; Chem. Abstr. 2005,
143, 477850. (c) Volk, B.; Barkóczy, J.; Simig, G.; Mezei, T.;
Kapiller-Dezsöfi, R.; Gacsályi, I.; Pallagi, K.; Gigler, G.; Lévay,
G.; Móricz, K.; Leveleki, C.; Sziray, N.; Szénási, G.; Egyed, A.;
Hársing, L. G. Preparation of piperazine derivatives of alkyl
oxindoles as 5-HT7 receptor active agents for treating or preventing
central nervous system or cardiovascular system disorders. WO
2005108363, 2005; Chem. Abstr. 2005, 143, 477984. (d) Volk, B.;
Barkóczy, J.; Simig, G.; Mezei, T.; Kapiller-Dezsöfi, R.; Gacsályi, I.;
Pallagi, K.; Gigler, G.; Lévay, G.; Móricz, K.; Leveleki, C.; Sziray,
N.; Szénási, G.; Egyed, A.; Hársing, L. G. Preparation of piperazine
derivatives of alkyl oxindoles for treating or preventing central nervous
system or cardiovascular disorders. WO 2005108364, 2005; Chem.
Abstr. 143, 477985. (e) Volk, B.; Barkóczy, J.; Simig, G.; Mezei, T.;
Kapiller-Dezsöfi, R.; Flórián, E.; Gacsályi, I.; Pallagi, K.; Gigler, G.;
Lévay, G.; Móricz, K.; Leveleki, C.; Sziray, N.; Szénási, G.; Egyed,
A.; Hársing, L. G. Preparation of piperazine-containing dialkyloxin-
doles that bind to 5-HT2C and R1 receptors for use against central
nervous system and other diseases. WO 2005109987, 2005; Chem.
Abstr. 2005, 143, 477989.
(42) Weisstaub, N. V.; Zhou, M.; Lira, A.; Lambe, E.; Gonzalez-Maeso,
J.; Hornung, J.-P.; Sibille, E.; Underwood, M.; Itohara, S.; Dauer,
W. T.; Ansorge, M. S.; Morelli, E.; Mann, J. J.; Toth, M.; Aghajanian,
G.; Sealfon, S. C.; Hen, R.; Gingrich, J. A. Cortical 5-HT2A receptor
signaling modulates anxiety-like behaviors in mice. Science 2006, 313,
536–540.
(43) Masse, F.; Hascoet, M.; Dailly, E.; Bourin, M. Effect of noradrenergic
system on the anxiolytic-like effect of DOI (5-HT2A/2C agonist) in the
four plate test. Psychopharmacology 2006, 183, 471–481.
(44) Mahé, C.; Loetscher, E.; Feuerbach, D.; Müller, W.; Seiler, M. P.
Schoeffter, Ph. Differential inverse agonist efficacies of SB-258719,
SB-258741 and SB-269970 at human recombinant serotonin 5-HT7
receptors. Eur. J. Pharmacol. 2004, 495, 97–102.
(46) Bojarski, A. J.; Duszyn´ska, B.; Kołaczowski, M.; Kowalski, P.;
Kowalska, T. The impact of spacer structure on 5-HT7 and 5-HT1A
receptor affinity in the group of long-chain arylpiperazine ligands.
Bioorg. Med. Chem. Lett. 2004, 14, 5863–5866.
(47) López-Rodríguez, M. L.; Porras, E.; Morcillo, M. J.; Benhamú,
B.; Soto, L. J.; Lavandera, J. L.; Ramos, J. A.; Olivella, M.;
Campillo, M.; Pardo, L. Optimization of the pharmacophore model
for 5-HT7R antagonism. Design and synthesis of new naphtholactam
and naphthosultam derivatives. J. Med. Chem. 2003, 46, 5638–5650.
(48) López-Rodríguez, M. L.; Porras, E.; Benhamú, B.; Ramos, J. A.;
Morcillo, M. J.; Lavandera, J. L. First pharmacophoric hypothesis
for 5-HT7 antagonism. Bioorg. Med. Chem. Lett. 2000, 10, 1097–
1100.
(45) (a) Volk, B.; Barkóczy, J.; Simig, G.; Mezei, T.; Kapiller-Dezsöfi,
R.; Gacsályi, I.; Pallagi, K.; Gigler, G.; Lévay, G.; Móricz, K.;
Leveleki, C.; Sziray, N.; Szénási, G.; Egyed, A.; Hársing, L. G.
Preparation of indol-2-one derivatives for the treatment of central
nervous disorders, gastrointestinal disorders and cardiovascular
disorders. WO 2005108390, 2005; Chem. Abstr. 2005, 143, 477847.
(b) Volk, B.; Barkóczy, J.; Simig, G.; Mezei, T.; Kapiller-Dezsöfi,
R.; Gacsályi, I.; Pallagi, K.; Gigler, G.; Lévay, G.; Móricz, K.;
Leveleki, C.; Sziray, N.; Szénási, G.; Egyed, A.; Hársing, L. G.
(49) Leopoldo, M.; Berardi, F.; Colabufo, N. A.; Contino, M.; Lacivita,
L.; Perrone, R.; Tortorella, V. Studies on 1-arylpiperazine derivatives
with affinity for rat 5-HT7 and 5-HT1A receptors. J. Pharm. Pharmacol.
2004, 56, 247–255.
(50) Peroutka, S. J.; Snyder, S. H. Multiple serotonin receptors: differential
binding of [3H]5-hydroxytryptamine, [3H]lysergic acid diethylamide
and [3H]spiroperidol. Mol. Pharmacol. 1979, 16, 687–699.
JM070279V