Synthesis, physicochemical and anticonvulsant properties of new N-4-arylpiperazin-1-yl amides of (2-aza-1,3-dioxospiro[4.4]non-2-yl)- and [4.5]dec-2-yl-propionic acid

Article abstract of DOI:10.1002/ardp.200700038

In continuation of the search of new anticonvulsants, a series of N-4-arylpiperazin-1-yl 2-aza-1,3-dioxospiro[4.4]non-2-yl- (5-8) and [4.5]dec-2-yl- (9-15) propionamides, structurally related to the previously described N-4-arylpiperazin-1-yl amides of 2-aza-1,3-dioxospiro[4.5]dec-2-yl- acetic acid, were synthesized. The designed compounds 5-15 were prepared by condensation of the formerly obtained (2-aza-1,3-dioxospiro[4.5]dec-2-yl)- (3) and (2-aza-1,3-dioxo[4.4]non-2-yl)-(4) propionic acids with the appropriately substituted 4-arylpiperazines, in the presence of the N,N-carbonyldiimidazole (CDIM) reagent. All the compounds were tested for their anticonvulsant activity in the maximum electroshock seizure (MES) and subcutaneous pentylenetetrazole (scPTZ) seizure threshold tests. Several compounds 7-10, 13 and 14 revealed protection in the MES screening.

Full text of DOI:10.1002/ardp.200700038

404
Arch. Pharm. Chem. Life Sci. 2007, 340, 404–408
Full Paper
Synthesis, Physicochemical and Anticonvulsant Properties
of New N-4-Arylpiperazin-1-yl Amides of (2-Aza-1,3-
dioxospiro[4.4]non-2-yl)- and [4.5]dec-2-yl)-propionic Acid
Jolanta Obniska, Krzysztof Kaminski, Lukasz Hondo, and Alfred Zejc
Department of Medicinal Chemistry, Jagiellonian University Medical College, Krakꢀw, Poland
In continuation of the search of new anticonvulsants, a series of N-4-arylpiperazin-1-yl 2-aza-1,3-
dioxospiro[4.4]non-2-yl- (5–8) and [4.5]dec-2-yl- (9–15) propionamides, structurally related to the
previously described N-4-arylpiperazin-1-yl amides of 2-aza-1,3-dioxospiro[4.5]dec-2-yl-acetic acid,
were synthesized. The designed compounds 5–15 were prepared by condensation of the for-
merly obtained (2-aza-1,3-dioxospiro[4.5]dec-2-yl)- (3) and (2-aza-1,3-dioxo[4.4]non-2-yl)-(4) pro-
pionic acids with the appropriately substituted 4-arylpiperazines, in the presence of the N,N-car-
bonyldiimidazole (CDIM) reagent. All the compounds were tested for their anticonvulsant activ-
ity in the maximum electroshock seizure (MES) and subcutaneous pentylenetetrazole (scPTZ)
seizure threshold tests. Several compounds 7–10, 13 and 14 revealed protection in the MES
screening.
Keywords: Anticonvulsant activity / N-4-arylpiperazin-1-yl-2-aza-1,3-dioxospiro[4.4]non-2-yl- and [4.5]dec-2-yl-propio-
namides / Pyrrolidine-2,5-diones /
Received: February 23, 2007; accepted: May 16, 2007
DOI 10.1002/ardp.200700038
Introduction
Numerous compounds are getting synthesized and
screened for their anticonvulsant activities each year. To
make the discovery of new anticonvulsants more
rational, several investigators identify structural frag-
ments that may enhance anticonvulsant properties and
Figure 1. Structure of ethosuximide, phenytoin and ameltolide.
permit also for orientating the synthesis of novel com-
pounds in which some of these active fragments can
appear [1]. One of the structural features that play a sig-
nificant role in relation to anti-epileptic activity is an
amide function [2, 3]. This moiety may be introduced
into a heterocyclic ring, e.g. ethosuximide, phenytoin or
as an anilide nucleus, e.g. ameltolide (Fig. 1.).
group of pyrrolidine-2,5-dione derivatives variously sub-
stituted at the nitrogen atom as well as at the position-3
of the imide ring [4–8]. In this series of compounds the
most promising were derivatives containing a 4-arylpi-
perazine moiety, connected to the imide nitrogen atom
by the alkylene spacer [9–11]. Their anticonvulsant prop-
erties depended on the kind of substitution mode at posi-
tion-3 of the pyrrolidine-2,5-dione ring, the length of the
alkylene chain joining the endocyclic imide nitrogen
atom and the 4-arylpiperazine fragment as well as the
nature of the substituents at the aromatic area.
In the course of developing new, potentially anticon-
vulsant agents, our attention has been focused on the
Correspondence: Jolanta Obniska, Department of Pharmaceutical
Chemistry, Jagiellonian University Medical College, Medyczna 9, 30-688
Krakow, Poland.
E-mail: mfobnisk@cyf-kr.edu.pl
Fax: +48 12 657-02-62
Taking into consideration a vital influence of amide
moiety on anticonvulsant activity, we have recently
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Arch. Pharm. Chem. Life Sci. 2007, 340, 404–408
Spirosuccinimid-2-yl Propionamides as Anticonvulsants
405
Table 1. Anticonvulsant and neurotoxicity screening results of
investigated compounds.
Com-
pound
Intraperitoneal injection in micea)
ASPb)
class
MES
scPTZ
TOXc)
0.5 [h] 4 [h]
0.5 [h] 4 [h]
0.5 [h] 4 [h]
5
6
7
8
9
10
11
12
13
14
15
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
3
3
2
2
2
2
3
3
2
2
3
300
300
300
300
–
30014
30014
30014
–
300
–
–
300
–
–
300
300
–
3025
–
a)
Doses of 30, 100 and 300 mg/kg were administrated. The fig-
ures in the table indicate the minimum dose (mg/kg),
whereby bioactivity was demonstrated. The dash (–) indicates
an absence of activity at the maximum dose administrated.
Toxicity screening: minimum dose of compound whereby
toxicity was exhibited. Response comments:14 unable to grasp
rotorod, 25 myoclonic jerks.
The ASP classification is as follows: 1 – anticonvulsant activ-
ity at doses of 100 mg/kg or less; 2 – anticonvulsant activity
at doses of 100 mg/kg and more; 3 – compound inactive at
doses of 300 mg/kg.
Scheme 1. Synthesis and structures of the obtained com-
pounds.
b)
b)
obtained a series of 2-aza-1,3-dioxospiro[4.5]dec-2-yl-acet-
amides with the 4-arylpiperazine derivatives as amide
function [12]. This molecules may be recognized as ana-
logues of respective N-[(4-arylpiperazine)-alkyl]-spirosucci-
nimides with an additional amide function in the alkyl
side chain. Several of those compounds were effective in
the maximal electroshock (MES) or subcutaneous metra- procedures described elsewhere [14], with 3-aminopro-
pionic acid yielded the corresponding 3-(1,3-dioxo-2-azas-
zole (scPTZ) screenings. On the other hand, the respective
piro[4.4]non-2-yl)- (3) or [4.5]dec-2-yl-propionic(4) acids.
N-phenyl and N-benzyl amides of 3-spirocycloalkylpyrro-
lidine-2,5-dione acetic acid were devoid of anticonvulsant These products were converted to the respective final 4-
arylpiperazine amides 5–15, by use of the amide-bond
formation reaction in the presence of the N,N-carbonyl-
diimidazole (CDIM) reagent. The structures of the com-
activity [13]. It proves the unique role of the 4-arylpipera-
zine fragment as pharmacophoric system of such type of
compounds.
In view of these data, in this work, we have designed pounds synthesized were confirmed by elemental anal-
ysis as well as examination of their 1H-NMR spectra.
and synthesized a new series of N-4-arylpiperazin-1-yl-2-
aza-1,3-dioxospiro[4.4]non-2-yl- (5–8) and [4.5]dec-2-yl- (9–
15) propionamides. The aim of this study was to evaluate Anticonvulsant activity
the influence of the introduction of an ethylene spacer The maximal electroshock (MES) and subcutaneous pen-
tylenetetrazole (scPTZ) tests are claimed to detect com-
pounds affording protection against generalized tonic-
clonic seizures and generalized absence seizures, respec-
tively. Thus, the MES and scPTZ screens have become the
most widely employed seizure models for early identifi-
cation of candidate anticonvulsants. The results of anti-
convulsant identification studies in mice are shown in
Table 1.
between the imide nitrogen atom and the carbonyl
amide group on the anticonvulsant activity, in compari-
son to the methylene analogues described previously.
Results and discussion
Chemistry
The results obtained revealed that, except for com-
pound 14, which was active in both MES and scPTZ tests,
Compounds 5–15 were synthesized according to
Scheme 1. First, the condensation reaction of starting 1-
carboxy-1-cyclopentane- (1) or 1-carboxy-1-cyclohexane- all other derivatives inhibited only electrically provoked
seizures (MES-test) 7–10, 13 or were inactive 5, 6, 11, 12,
acetic (2) acids, which were obtained according to the
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406
J. Obniska et al.
Arch. Pharm. Chem. Life Sci. 2007, 340, 404–408
using the developing systems A: benzene : ethyl acetate : acetone
(10 : 5 : 1) and B: chloroform : acetone (9 : 1). Spots were detected
by their absorption under UV light (k = 254 nm) and by visualiza-
tion with 0.05 mol iodine in 10% HCl. The chemical structures
were confirmed by elemental and spectral analyses (1H-NMR). 1H-
NMR spectra were obtained in a Varian Mercury 300 MHz spec-
trometer (Varian Inc., Palo Alto, CA, USA), in CDCl3, with TMS as
an internal standard. Chemical shifts are reported in d values
(ppm) and J values in Hertz (Hz). Signal multiplicities were given
by the following abbreviations: s (singlet), br. s (broad singlet),
dd (doublet of doublets), t (triplet), dt (doublet of triplets), m
(multiplet). Elemental analyses for C, H, N were carried out with
an Elementar Vario EL III (Hanau, Germany).
15. In the series of 4-arylpiperazin-1-yl-(2-aza-1,3-dioxo-
spiro[4.5]dec-2-yl)-propionamides, the most active were
compound 9 and its analogues with fluoro- 10, methyl- 13
and methoxy- 14 substituents at the position-2 of the 4-
arylpiperazine moiety. These molecules protected 100%
of the animals tested at a dose of 300 mg/kg at 0.5 h. Addi-
tionally, compound 14 exhibited anti-scPTZ activity at a
dose of 30 mg/kg at 0.5 h, however, at the same concen-
tration provoked myoclonic jerks.
Change of the size of the cycloalkyl unit from cyclohex-
ane to cyclopentane, caused only a marginal decrease in
anticonvulsant activity which was observed in a group of
4-arylpiperazin-1-yl amides of (2-aza-1,3-dioxospiro[4.4]-
non-2-yl)-propionic acid 5–8. In this series of compounds,
the 3-chloro- 7 and 2-methyl- 8 derivatives were active in
the MES test at a dose of 300 mg/kg at 0.5 h.
General procedure for the preparation of (2-aza-1,3-
dioxospiro[4.4]non-2-yl)- (3) and [4.5]dec-2-yl)-propionic
acids (4)
The total of 1-carboxy-1-cyclopentane- (1) or 1-carboxy-1-cyclo-
hexane-acetic (2) acids (0.04 mol) were dissolved in 20 mL of
water and 3-aminopropionic acid (0.04 mol) was gradually
added. The mixture was heated in an oil bath with simultaneous
distillation of water. After the water was completely removed,
the temperature of the reaction was raised to 1808C and main-
tained at that level for approx. 1.5 h. The crude products were
recrystallized from ethanol.
In the neurological toxicity screening, compounds 7–
9, 11 and 14 were found to be toxic at the maximum
administrated dose (300 mg/kg). The mice were unable to
grasp the rotorod after administration of derivatives 7, 8
and 9 at a dose of 300 mg/kg.
In conclusion, the introduction of an ethylene spacer
between the imide nitrogen atom and the carbonyl
amide group decreased the anticonvulsant activity in
comparison to 4-arylpiperazin-1-yl amides of (2-aza-1,3-
dioxospiro[4.5]dec-2-yl)-acetic acid described previously
[12]. As mentioned above, the amide function is one of
the structural elements that play a significant role
regarding the anticonvulsant activity for several groups
of compounds. However, the results of our studies indi-
cate that incorporation of the additional amide function
into the alkyl chain joining the nitrogen atom of succini-
mide and 4-arylpiperazine moiety decreased the anticon-
vulsant properties in relation to the respective alkylene
analogues.
2-Aza-1,3-dioxospiro[4.4]non-2-yl-propionic acid 3*
White solid (yield 82%), mp. 113–1158C. 1H-NMR (CDCl3,
300 MHz) d (ppm): 1.63–2.12 (8H, m, –C4H8–), 2.58 (2H, s, imide),
2.68 (2H, t, CH2–CH2–CO, J = 7.18 Hz), 3.82 (2H, t, CH2-CH2, J =
7.18 Hz), 10.41 (1H, br. s, COOH). Anal. calcd. for C11H15N1O4: C,
58.66; H, 6.71; N, 6.22. Found: C, 58.40; H, 6.60; N, 6.10.
* Mondon [15] described this compound as by-product; how-
ever, no physicochemical and spectral data were available so far.
2-Aza-1,3-dioxospiro[4.5]dec-2-yl-propionic acid 4
White solid (yield 78%), mp. 120–1228C. 1H-NMR (CDCl3,
300 MHz) d (ppm): 1.29–1.78 (8H, m, –C4H8–), 2.54 (2H, s, imide),
2.64 (2H, t, CH2–CH2–CO, J = 7.18 Hz), 3.78 (2H, t, CH2–CH2, J =
7.18 Hz), 10.32 (1H, br. s, COOH). Anal. calcd. for C12H17N1O4: C,
60.24; H, 7.16; N, 5.85. Found: C, 60.0; H, 7.10; N, 6.00.
The authors wish to thank Dr James Stables for providing us
with pharmacological data through the Anti-epileptic Drug
Development Program (Epilepsy Branch, National Institute of
Neurological Disorders and Stroke, National Institute of
Health, Bethesda, MD, USA).
General procedure for the preparation of compounds 5-15
The obtained 2-aza-1,3-dioxospiro[4.4]non-2-yl- (3) or [4.5]dec-2-yl-
propionic (4) acids (0.01 mol) were dissolved in 20 mL of DMF
and N,N-carbonyl-diimidazole (0.01 mol) was added. The mixture
was stirred for 0.5 h at a room temperature. Afterwards, the
appropriately substituted 4-arylpiperazine (0.01 mol) was added.
After 24 h of stirring at room temperature, the reaction mixture
was left in an ice cold bath. The product was precipitated with
cold water and was purified by recrystallization from isopropyl
alcohol.
Experimental
Chemistry
N-(4-Phenylpiperazin-1-yl)amide of 2-aza-1,3-
dioxospiro[4.4]non-2-yl-propionic acid 5
Compound 5 was obtained as white solid (yield 88%), mp. 123–
1258C. 1H-NMR (CDCl3, 300 MHz) d (ppm): 1.61–2.17 (8H, m,
–C4H8–), 2.58 (2H, s, imide), 2.69 (2H, t, CH2–CH2–CO, J = 7.69 Hz),
3.13–3.19 (4H, m, piperazine), 3.61 (2H, br. s, piperazine), 3.75
(2H, br. s, piperazine), 3.84 (2H, t, CH2–CH2, J = 7.69 Hz), 6.89–
All the chemicals and solvents were purchased from Merck
(Darmstadt, Germany) and were used without further purifica-
tion. Melting points (mp.) were determined in open capillaries
on a Bꢀchi 353 melting point apparatus (Bꢀchi Labortechnik,
Flawil, Switzerland) and are uncorrected. The purity of the com-
pounds was confirmed by the thin-layer chromatography (TLC)
performed on Merck silica gel 60 F254 aluminium sheets (Merck),
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Arch. Pharm. Chem. Life Sci. 2007, 340, 404–408
Spirosuccinimid-2-yl Propionamides as Anticonvulsants
407
6.94 (2H, m, arom.), 7.24–7.31 (3H, m, arom.). Anal. calcd. for
C21H27N3O3: C, 68.27; H, 7.37; N, 11.37. Found: C, 68.20; H, 7.40;
N, 11.30.
N-[4-(2-Chlorophenyl)-piperazin-1-yl]amide of 2-aza-1,3-
dioxospiro[4.5]dec-2-yl-propionic acid 11
Compound 11 was obtained as white solid (yield 63%), mp. 126–
1288C. 1H-NMR (CDCl3, 300 MHz) d (ppm): 1.19–1.84 (10H, m,
–C5H10–), 2.54 (2H, s, imide), 2.66 (2H, t, CH2–CH2–CO, J = 7.69 Hz),
2.99–3.07 (4H, m, piperazine), 3.62 (2H, t, piperazine, J =
4.87 Hz), 3.76 (2H, t, piperazine, J = 4.99 Hz), 3.83 (2H, t, CH2–CH2,
J = 7.56 Hz), 6.98-7.03 (2H, m, arom.), 7.20-7.23 (1H, m, arom.),
7.38 (1H, dd, arom., J = 6.66 Hz). Anal. calcd. for C22H28N3O3Cl: C,
63.22; H, 6.77; N, 10.08. Found: C, 63.0; H, 6.70; N, 9.85.
N-[4-(2-Fluorophenyl)-piperazin-1-yl]amide of 2-aza-1,3-
dioxospiro[4.4]non-2-yl-propionic acid 6
Compound 6 was obtained as white solid (yield 77%), m.p 134–
1368C. 1H-NMR (CDCl3, 300 MHz) d (ppm): 1.59–2.16 (8H, m,
–C4H8–), 2.57 (2H, s, imide), 2.67 (2H, t, CH2–CH2–CO, J = 7.69 Hz),
3.02–3.10 (4H, m, piperazine), 3.61 (2H, t, piperazine, J =
5.13 Hz), 3.76 (2H, t, piperazine, J = 5.13 Hz), 3.82–3.87 (2H, m,
CH2–CH2), 6.90–7.10 (4H, m, arom.). Anal. calcd. for C21H26N3O3F:
C, 65.18; H, 6.76; N, 10.85. Found: C, 65.0; H, 6.90; N, 10.80.
N-[4-(3-Chlorophenyl)-piperazin-1-yl]amide of 2-aza-1,3-
dioxospiro[4.5]dec-2-yl-propionic acid 12
Compound 12 was obtained as white solid (yield 89%), mp. 159–
1618C. 1H-NMR (CDCl3, 300 MHz) d (ppm): 1.19–1.84 (10H, m,
–C5H10–), 2.54 (2H, s, imide), 2.66 (2H, t, CH2–CH2–CO, J = 7.56 Hz),
3.14–3.22 (4H, m, piperazine), 3.60 (2H, t, piperazine, J =
5.12 Hz), 3.71–3.74 (2H, t, piperazine, J = 5.13 Hz), 3.82 (2H, t,
CH2–CH2, J = 7.56 Hz), 6.77–6.90 (3H, m, arom.), 7.18 (1H, t, arom.
J = 8.08 Hz). Anal. calcd. for C22H28N3O3Cl: C, 63.22; H, 6.77; N,
10.08. Found: C, 63.40; H, 6.50; N, 9.80.
N-[4-(3-Chlorophenyl)-piperazin-1-yl]amide of 2-aza-1,3-
dioxospiro[4.4]non-2-yl-propionic acid 7
Compound 7 was obtained as white solid (yield 74%), mp. 99–
1018C. 1H-NMR (CDCl3, 300 MHz) d (ppm): 1.62–2.17 (8H, m,
–C5H10-), 2.57 (2H, s, imide), 2.7 (2H, t, CH2–CH2–CO, J = 7.69 Hz),
3.17 (4H, dt, piperazine, J = 5.01 Hz), 3.10 (2H, t, piperazine, J =
5.01 Hz), 3.73 (2H, t, piperazine, J = 5.21 Hz), 3.84 (2H, dd, CH2–
CH2, J = 6.90 Hz), 6.76–6.87 (3H, m, arom.), 7.15–7.20 (1H, m,
arom.). Anal. calcd. for C21H26N3O3Cl: C, 62.45; H, 6.49; N, 10.40.
Found: C, 62.30; H, 6.50; N, 10.40.
N-[4-(2-Methylphenyl)-piperazin-1-yl]amide of 2-aza-1,3-
dioxospiro[4.5]dec-2-yl-propionic acid 13
Compound 13 was obtained as white solid (yield 62%), mp. 120–
1
1228C. H-NMR (CDCl3, 300 MHz) d (ppm): 1.19–1.84 (10H, m,
–C5H10–), 2.33 (3H, s, CH3), 2.54 (2H, s, imide), 2.67 (2H, t, –CH2–
CH2–CO, J = 7.69 Hz), 2.86 (2H, t, piperazine, J = 5.00 Hz), 2.92 (2H,
t, piperazine, J = 5 Hz), 3.60 (2H, t, piperazine, J = 4.74 Hz), 3.74
(2H, t, piperazine, J = 4.87 Hz), 3.84 (2H, t, CH2–CH2, J = 7.56 Hz),
7.02 (2H, t, J = 8.08 Hz, arom.), 7.15–7.20 (2H, m, arom.). Anal.
calcd. for C23H31N3O3: C, 69.59; H, 7.87; N, 10.58. Found: C, 69.40;
H, 7.70; N, 10.40.
N-[4-(2-Methylphenyl)-piperazin-1-yl]amide of 2-aza-1,3-
dioxospiro[4.4]non-2-yl-propionic acid 8
Compound 8 was obtained as white solid (yield 61%), mp. 102–
1048C. 1H-NMR (CDCl3, 300 MHz) d (ppm): 1.62–2.17 (8H, m,
–C4H8–), 2.32 (3H, s, CH3), 2.58 (2H, s, imide), 2.68 (2H, t, CH2–CH2–
CO, J = 7.95 Hz), 2.85–2.93 (4H, m, piperazine), 3.60 (2H, t, piper-
azine, J = 4.86 Hz), 3.74 (2H, t, piperazine, J = 4.87 Hz), 3.83–3.88
(2H, m, CH2–CH2), 6.90–6.99 (2H, m, arom.), 7.00–7.20 (2H, m,
arom.). Anal. calcd. for C22H29N3O3: C, 68.99; H, 7.63; N, 10.97.
Found: C, 68.71; H, 7.40; N, 10.70.
N-[4-(2-Methoxyphenyl)-piperazin-1-yl]amide of 2-aza-
1,3-dioxospiro[4.5]dec-2-yl-propionic acid 14
Compound 14 was obtained as white solid (yield 67%), mp. 128–
1
1298C. H-NMR (CDCl3, 300 MHz) d (ppm): 1.20–1.80 (10H, m,
–C5H10–), 2.54 (2H, s, imide), 2.66 (2H, t, –CH2–CH2–CO, J =
7.69 Hz), 3.05 (4H, br. s, piperazine), 3.62 (2H, br. s, piperazine),
3.77 (2H, br. s, piperazine), 3.83 (2H, t, –CH2–CH2–, J = 7.69 Hz),
3.88 (3H, s, OCH3), 6.87–7.05 (4H, m, arom.). Anal. calcd. for
C23H31N3O4: C, 66.89; H, 7.57; N, 10.17. Found: C, 66.90; H, 7.40;
N, 9.88.
N-(4-Phenylpiperazin-1-yl)-amide of 2-aza-1,3-
dioxospiro[4.5]dec-2-yl-propionic acid 9
Compound 9 was obtained as white solid (yield 74%), mp. 139–
1418C. 1H-NMR (CDCl3, 300 MHz) d (ppm): 1.20–1.84 (10H, m,
–C5H10–), 2.54 (2H, s, imide), 2.67 (2H, t, CH2–CH2–CO, J = 7.69 Hz),
3.12–3.19 (4H, m, piperazine), 3.60 (2H, br, s, piperazine), 3.74
(2H, br. s, piperazine), 3.83 (2H, t, CH2–CH2, J = 7.55 Hz), 6.89–
6.93 (2H, m, arom.), 7.28–7.31 (3H, d, arom., J = 8.72 Hz). Anal.
calcd. for C22H29N3O3: C, 68.99; H, 7.63; N, 10.97. Found: C, 69.10;
H, 7.50; N, 10.80.
N-[4-(3-Methoxyphenyl)-piperazin-1-yl]amide of 2-aza-
1,3-dioxospiro[4.5]dec-2-yl-propionic acid 15
Compound 15 was obtained as white solid (yield 77%), mp. 125–
1
1278C. H-NMR (CDCl3, 300 MHz) d (ppm): 1.20–1.84 (10H, m,
–C5H10–), 2.54 (2H, s, imide), 2.66 (2H, t, –CH2–CH2–CO, J =
7.56 Hz), 3.13–3.19 (4H, m, piperazine), 3.59 (2H, br. s, pipera-
zine), 3.73 (2H, br. s, piperazine), 3.79 (3H, s, OCH3), 3.83 (2H, t,
CH2–CH2–, J = 7.44 Hz) 6.45-6.58 (3H, m, arom.), 7.18 (1H, t, arom.
J = 8.20 Hz). Anal. calcd. for C23H31N3O4: C, 66.89; H, 7.57; N,
10.17. Found: C, 66.60; H, 7.60; N, 10.30.
N-[4-(2-Fluorophenyl)-piperazin-1-yl]amide of 2-aza-1,3-
dioxospiro[4.5]dec-2-yl-propionic acid 10
Compound 10 was obtained as white solid (yield 69%), mp. 129–
1318C. 1H-NMR (CDCl3, 300 MHz) d (ppm): 1.59–2.16 (8H, m,
–C4H8–), 2.57 (2H, s, imide), 2.68 (2H, t, CH2–CH2–CO, J = 7.69 Hz),
3.02–3.10 (4H, m, piperazine), 3.61 (2H, t, piperazine, J =
5.13 Hz), 3.76 (2H, t, piperazine, J = 5.13 Hz), 3.82–3.87 (2H, m,
CH2–CH2), 6.90–7.10 (4H, m, arom.). Anal. calcd. for C22H28N3O3F:
C, 65.90; H, 7.04; N, 10.48. Found: C, 65.70; H, 7.20; N, 10.70.
Pharmacology
Compounds 5–15 were pharmacologically pre-evaluated within
the Antiepileptic Drug Development (ADD) Program, Epilepsy
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408
J. Obniska et al.
Arch. Pharm. Chem. Life Sci. 2007, 340, 404–408
Branch, Neurological Disorders Program, National Institute of
the Neurological and Communicative Disorders and Stroke
(NINCDS), Bethesda, using procedures described elsewhere
[16, 17].
Phase I studies of the compounds investigated involved three
testes: maximal electroshock seizure (MES), subcutaneous penty-
lenetrazole seizure (scPTZ) and neurological toxicity (TOX). Male
albino mice (CF#1 strain, weighing 18-25 g) were used as experi-
mental animals.
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investigated was classed with the following categories: active at
doses of 100 mg/kg or less (class 1), active at doses of greater than
100 mg/kg (class 2), inactive at 300 mg/kg (class 3). The results of
preliminary screening for compounds 5–15 are presented in
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i 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.archpharm.com