Synthesis and Anticonvulsant Activity of Substituted-1,3-diazaspiro[4.5]decan-4-ones

Article abstract of DOI:10.1002/ardp.201500092

A series of novel spiroimidazolidinone derivatives 6a-d and 8a-x were synthesized and biologically evaluated for their anticonvulsant activity in the maximal electroshock seizure (MES) assay and the subcutaneous pentylenetetrazole (scPTZ) screening test. Compound 8w was the most active derivative in the scPTZ screening test with an ED₅₀ value by about 5- and 83.6-fold lower than those of phenobarbital and ethosuximide as reference drugs, respectively. Most of the tested compounds exhibited moderate to weak activity in the MES screen test, except for 8a which displayed 100% protection at 0.09 mmol/kg. Moreover, all the test compounds did not show any minimal motor impairment in the neurotoxicity test.

Full text of DOI:10.1002/ardp.201500092

RCHH HARM
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Arch. Pharm. Chem. Life Sci. 2015, 348, 575–588
Archiv der Pharmazie
Full Paper
Synthesis and Anticonvulsant Activity of Substituted-1,3-
diazaspiro[4.5]decan-4-ones
Mohamed Nabil Aboul-Enein1, Aida Abdel Sattar El-Azzouny1, Ola Ahmed Saleh1,
Kamilia Mahmoud Amin2, Yousreya Ali Maklad3, and Rasha Mohamed Hassan1
1
Pharmaceutical and Medicinal Chemistry Department, Medicinal Chemistry Group, Pharmaceutical and
Drug Industries Research Division, National Research Centre (ID: 60014618), Dokki, Giza, Egypt
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Cairo University, Cairo, Egypt
Pharmaceutical and Medicinal Chemistry Department, Pharmacology Group, Pharmaceutical and Drug
Industries Research Division, National Research Centre (ID: 60014618), Dokki, Giza, Egypt
2
3
A series of novel spiroimidazolidinone derivatives 6a–d and 8a–x were synthesized and biologically
evaluated for their anticonvulsant activity in the maximal electroshock seizure (MES) assay and the
subcutaneous pentylenetetrazole (scPTZ) screening test. Compound 8w was the most active derivative in
the scPTZ screening test with an ED50 value by about 5- and 83.6-fold lower than those of phenobarbital
and ethosuximide as reference drugs, respectively. Most of the tested compounds exhibited moderate to
weak activity in the MES screen test, except for 8a which displayed 100% protection at 0.09 mmol/kg.
Moreover, all the test compounds did not show any minimal motor impairment in the neurotoxicity test.
Keywords: Anticonvulsants / 1,3-Diazaspiro[4.5]decan-4-ones / Epilepsy
Received: March 12, 2015; Revised: April 15, 2015; Accepted: April 17, 2015
DOI 10.1002/ardp.201500092
Additional supporting information may be found in the online version of this article at the publisher’s web-site.
:
development of new more effective and less toxic antiepilep-
tic agents.
Introduction
Epilepsy is a chronic neurological disorder characterized by
recurrent unprovoked seizures [1]. These seizures are tran-
sient signs and/or symptoms of abnormal excessive neuronal
activity in the brain [2]. Despite the introduction of many new
antiepileptic drugs, estimates suggest that available antiepi-
leptic drugs fail to control the seizures in about 20–30% of
patients [3, 4]. Moreover, these medications are accompanied
with severe adverse effects such as gingival hyperplasia,
ataxia, megaloblastic anemia, and hepatotoxicity [5, 6].
Accordingly, there is an importunate demand for the
Rational studies find it difficult to discover new antiepilep-
tic drugs due to insufficient information regarding molecular
pathway of human epilepsy and complex mechanisms of
action for the majority of available antiepileptic drugs [7].
Therefore, the development of new chemical entities having
anticonvulsant activity is paramount and could be performed
through the traditional screening investigations as well as the
hybrid pharmacophoric approach [8]. This approach relies on
the use of two or more pharmacophores, each with potential
pharmacological activity to be combined in one molecule,
aiming to produce candidates with better pharmacological
profile.
Through literature survey, it was revealed that imidazoli-
din-4-ones represent an interesting class of compounds with
respect to biological activity such as cholesterol-absorption
inhibitors [9], antimalarials [10], and anxiolytics [11]. Also,
certain imidazolidin-4-ones such as compound I (Fig. 1)
exhibited anticonvulsant activity against maximal electro-
shock and PTZ-induced seizure tests [12]. It is worth noticing
that one of the pharmacophoric groups inserted in
Correspondence: Prof. Mohamed Nabil Aboul-Enein, Pharma-
ceutical and Medicinal Chemistry Department, Medicinal Chem-
istry Group, Pharmaceutical and Drug Industries Research
Division, National Research Centre (ID: 60014618), 12622 Dokki,
Giza, Egypt.
E-mail: mnaboulenein@yahoo.com
Fax: þ20-237601877
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maximal electroshock seizure (MES) test. Moreover, many
geminally disubstituted cyclohexane derivatives have been
proven to elicit anticonvulsant profile such as gabapentin
(VI) [16]. In the same vein, Aboul-Enein et al. disclosed the
preparation and the anticonvulsant potential of several
geminally disubstituted cyclohexane derivatives VII,VIII, XI,
and X in the PTZ and maximal electroshock-induced seizure
tests [17–20]. In addition, it was reported that some
compounds bearing the pharmacophoric aminoacyl moiety
such as remacemide XI [21], safinamide XII [22], XIII [23], and
XIV [24] possessed pronounced anticonvulsant profile (Fig. 2).
Based on the aforementioned considerations and in
continuation of our research program on the design and
synthesis of new anticonvulsant candidates, it was deemed
valuable to prepare novel substituted-1,3-diazaspiro[4.5]-
decan-4-ones having the general hybrid structures 6a–d and
8a–x. These newly synthesized compounds were evaluated for
their anticonvulsant potential against maximal MES and the
subcutaneous pentylenetetrazole (scPTZ) model in mice.
Results and discussion
Chemistry
The synthesis of the target compounds 6a–d and 8a–x and
their intermediates is illustrated in Scheme 1. 1,3-Diazaspiro-
[4.5]decane-2,4-dione (2) was synthesized from cyclohexa-
none (1) in the presence of potassium cyanide and ammonium
carbonate in 50% ethanol according to the Bucherer–Bergs
reaction [25]. The hydantoin 2 was subjected to hydrolysis
under alkaline conditions for 72 h to yield 1-aminocyclohex-
anecarboxylic acid (3). Subsequently, protection of the amino
acid 3 was successfully achieved using di-tert-butyl dicarbon-
ate (Boc)2O in the presence of 3.8 M sodium hydroxide in THF
to furnish the corresponding N-Boc derivative 4. The desired
1-amino-N-substituted cyclohexanecarboxamides (5a and 5b)
were prepared by a previously described mixed anhydride
coupling procedure which involved reaction of
a tert-
butoxycarbonyl (Boc)-protected amino acid with ethylchlor-
oformate and an arylamine in the presence of triethylamine.
Subsequent deprotection of the coupled product using dry
HCl gas afforded the respective 1-amino-N-substituted cyclo-
hexanecarboxamides (5a and 5b). Cyclization of the latter
compounds 5a and 5b was successfully accomplished by
reacting with the appropriate aldehyde in absolute ethanol to
give the respective target spiro secondary amines 6a–d. The IR
spectra showed NH bands of 6a–d at 3291–3343 cmꢀ1. The
1
formation of 6a and 6b was confirmed through the H NMR
spectra by the presence of CH2 of the imidazolidine ring as a
singlet at d 4.77 and 4.69 ppm, respectively. Moreover, NH
proton appeared at d 2.07 and 1.99 ppm along with cyclohexyl
protons and aromatic protons at d 1.33–1.80 and 7.12–
7.56 ppm, respectively. Meanwhile, in the substituted C-2
analogs 6c and 6d the CH proton appeared as a singlet at 5.97
and 5.95, respectively, and new signals were observed at the
aromatic region. The 13C NMR spectrum of 6a revealed the
Figure 1. Reported anticonvulsant compounds and their
structural relation to the target compounds 6a–d and 8a–x.
compounds studied for their anticonvulsant activity is the
anilide moiety, for example, ameltolide (II) [13], ralitoline
(III) [14], as well as some phthalimide derivatives IV and V [15]
(Fig. 1) which exhibited potent anticonvulsant potential in
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Arch. Pharm. Chem. Life Sci. 2015, 348, 575–588
Anticonvulsant Activity of Diazaspirodecan-4-ones
Archiv der Pharmazie
Figure 2. Structuresofsomeanticonvulsantswiththeaminoacylappendageandtheirstructuralrelationtothetargetcompounds8a–x.
presence of CH2 at d 62.38 ppm while in 6d the CH carbon was
observed downfield at d 75.49 ppm. Subsequent chloroacety-
lation of 6a–d was performed using chloroacetyl chloride in
dry benzene in the presence of anhydrous potassium
carbonate to obtain the corresponding chloroacetylated
derivatives 7a–d. The molecules 7a–d showed the absence
of NH in their IR and 1H NMR spectra as well as the existence of
two carbonyl groups in 13C NMR spectra. Finally, the
preparation of the target compounds 8a–x was achieved by
condensation of 7a–d with the appropriate amine. The
1H NMR spectrum of the prototype compound 8a displayed
signals of ethyl group as triplet and quartet at d 1.03–1.05 and
7.16–7.57 ppm, respectively. The 13C NMR spectrum of 8a
confirmed the presence of 14 types of carbons where it
displayed an upfield peak due to CH3 of ethyl group at d
11.78 ppm and the peak of CH2 of ethyl group at d 47.8 ppm.
–
Furthermore, cyclohexyl carbons, CH –C O, CH2–N and
–
2
aromatic carbons were found in their expected region as
well as the carbonyl carbons which were observed downfield
at d 168.27 and 171.93 ppm. The structures of the new
compounds in the present investigation were further
confirmed by elemental analyses and the mass spectral data.
Anticonvulsant activity
–
2.58–2.59 ppm, respectively. Also the protons of CH –C O and
The use of predictable animal models is essential for the
discovery of new bioactive candidates for treatment of
epilepsy. The protocol given by the Epilepsy section of the
National Institute of Neurological Disorders and Stroke
–
2
CH2–N appeared as singlet at d 3.22 and 5.46 ppm, respective-
ly. Moreover, the cyclohexyl and aromatic protons were
observed at the expected chemical shifts at d 1.3–2.76 and
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Scheme 1. General method for the synthesis of the target compounds 6a–d and 8a–x. Reagents and conditions: (i) KCN, (NH4)2CO3,
50% ethanol, 55°C, 24 h; (ii) Ba(OH)2, H2O, reflux, 72 h; (iii) (Boc)2O, 3.8 M NaOH, THF, r.t., 15 h; (iv) a) Et3N, EtOCOCl, THF, r.t., 18 h; b)
HCl gas, DCM; (v) R2CHO, ethanol, reflux, 18 h; (vi) ClCH2COCl, anhyd. K2CO3, benzene, reflux, 18 h; (vii) appropriate amine, toluene,
90°C, 20 h.
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Anticonvulsant Activity of Diazaspirodecan-4-ones
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(NINIDS) allotted the use of the standard procedure adopted
by the Antiepileptic Drug Development (ADD) program
named “the gold standard screen” [26], which includes three
in vivo animal models: (i) the scPTZ screen, (ii) the MES screen,
and (iii) the neurotoxicity screen. The scPTZ screen identifies
compounds that elevate seizure threshold while MES screen
evaluates the ability of the test compound to prevent seizure
spread and the neurotoxicity identifies the minimal motor
impairment. Moreover, compounds exhibited 100% protec-
tion against induced seizures were subjected to median
effective dose (ED50) evaluation.
different congeners of this series was arranged in the
following decreasing order: 8w > 8o > 6c > 8q > 8m ¼ 8n ¼ 8r
¼ 8t ¼ 8x > 8u > 6d > 8s ¼ 8v > 8p.
Regarding the MES test, the dose which exerted the
maximum anticonvulsant protection in the scPTZ screening
has been selected. In this screening test, compound 8a
(ED50 ¼ 0.075 mmol/kg) was the most active one. It exhibited
100% protection at dose 0.09 mmol/kg and possessed less
potent effect than the reference drug diphenylhydantoin
(ED50 ¼ 0.034 mmol/kg) by about twofold. Compound 8d
(R1 ¼ H, R3, R4 ¼ piperidin-1-yl) (0.092 mmol/kg) displayed
83% protection effect, while compounds 8c, 8q, and 8r
exhibited equipotent anticonvulsant effect of 66%. On the
other hand, compounds 6c, 8m, and 8x were devoid of
anticonvulsant activity, meanwhile the rest of the compounds
exhibited 16–50% protection (Table 1).
The initial anticonvulsant activity (Phase I screening) of the
newly synthesized compounds 6a–d and 8a–x expressed as %
protection as well as their neurotoxicity are presented in
Table 1. The obtained data revealed that all the compounds
were effective in scPTZ screen while most of them were
effective in MES screen. Concerning the scPTZ screen, in the 2-
unsubstituted-3-aryl-1,3-diazaspiro[4.5]decan-4-ones series
(6a–b and 8a–l) where R2 ¼ H, compounds 6a (R1 ¼ H) (ED50
¼ 0.1 mmol/kg), 8b (R1 ¼ H, R3 ¼ R4 ¼ n-C3H7) (ED50 ¼ 0.064
mmol/kg), 8c (R1 ¼ H, R3, R4 ¼ pyrrolidin-1-yl) (ED50 ¼ 0.058
mmol/kg), 8f (R1 ¼ H, R3, R4 ¼ 1H-imidazol-1-yl) (ED50 ¼ 0.07
mmol/kg), and 8l (R1 ¼ CH3, R3, R4 ¼ 1H-imidazol-1-yl) (ED50
¼ 0.07 mmol/kg) were the most potent congeners in this
series displaying 100% protection against PTZ-induced
seizures at dose levels of 0.08–0.147 mmol/kg. These com-
pounds were nearly equipotent or less potent than pheno-
barbital (ED50 ¼ 0.056 mmol/kg) and most of them were more
potent than ethosuximide (ED50 ¼ 0.92 mmol/kg). Moreover,
compounds 6b (R1 ¼ CH3), 8a (R1 ¼ H, R3 ¼ R4 ¼ C2H5), 8e
(R1 ¼ H, R3, R4 ¼ morpholin-4-yl), 8h (R1 ¼ CH3, R3 ¼ R4 ¼ n-
C3H7), 8i (R1 ¼ CH3, R3, R4 ¼ pyrrolidin-1-yl), and 8k (R1 ¼ CH3,
R3, R4 ¼ morpholin-4-yl) exerted anticonvulsant potential of
83% at dose levels of 0.11, 0.09, 0.092, 0.067, 0.078, and
0.08 mmol/kg, respectively. The different congeners of this
series showed anticonvulsant activity in the following
decreasing order: 8c > 8b > 8l ¼ 8f > 6a > 8h > 8i ¼ 8k > 8a
¼ 8e > 6b > 8d ¼ 8j > 8g.
Interestingly, in the neurotoxicity screen test, all the
compounds did not show any minimal motor impairment at
the maximum administrated dose.
It could be revealed from the scPTZ screening results that in
the unsubstituted secondary amines (6a–d), compound 6c was
the most active one while removal of phenyl group from C-2
of the imidazolidine ring as in compounds 6a and 6b
decreased the activity. Introduction of aminoacyl moeity on
N-1 of the imidazolidine ring of 6a and 6c greatly affected the
anticonvulsant activities in 8a–f and 8m–r. In the compounds
having either diethylamino group or saturated heterocyclic
amine, for example, pyrrolidine, piperidine, or morpholine,
the presence of phenyl moeity on C-2 of the imidazolidine
ring (8m, 8o, 8p, and 8q) augmented the anticonvulsant
activity against scPTZ-induced seizures more than the
unsubstituted C-2 series (8a, 8c, 8d, and 8e). Meanwhile, in
the compounds having slightly longer aliphatic amine chain,
that is, di-n-propylamino group or unsaturated heterocyclic
amine, that is, imidazole moeity, the unsubstituted C-2
derivatives 8b and 8f were more active than the 2-phenyl
analogs 8n and 8r. Also, upon introduction of the aminoacyl
moeity to 6b and 6d, their 2-phenyl analogs 8s–w were found
to be more active than the C-2 unsubstituted ones 8g–k except
in the imidazole derivatives where 8l is more potent than 8x.
From the above-mentioned data, it could be observed that in
most derivatives the presence of phenyl group in C-2
enhanced the activity of the tested compounds in the scPTZ
screen more than the unsubstituted ones. Concerning the
relation between the substitution pattern in the anilide
moeity of 6a–d and the anticonvulsant activity against scPTZ
screen, it was found that the introduction of methyl
substitution at para position of the aromatic ring attenuated
the activity from 100% in 6a and 6c to 83% in 6b and 6d,
meanwhile the p-methyl substitution on the anilide moeity of
8a–x does not clearly affect the anticonvulsant activity against
scPTZ-induced seizures.
In addition, in the 2-phenyl-3-aryl-1,3-diazaspiro[4.5]-
decan-4-ones series (6c–d and 8m–x) where R2 ¼ phenyl,
compounds 6c (R1 ¼ H) (ED50 ¼ 0.03 mmol/kg), 8o (R1 ¼ H,
R3, R4 ¼ pyrrolidin-1-yl) (ED50 ¼ 0.016 mmol/kg), and 8w (R1 ¼
CH3, R3, R4 ¼ morpholin-4-yl) (ED50 ¼ 0.011 mmol/kg) showed
100% anticonvulsant protection compared to the reference
drugs phenobarbital (ED50 ¼ 0.056 mmol/kg) and ethosuxi-
mide (ED50 ¼ 0.92 mmol/kg). Those compounds exhibited 1.8-,
3.5-, and 5-fold more potent anticonvulsant effect than
phenobarbital as well as 30.6-, 57.5-, and 83.6-fold more
potent than ethosuximide, respectively. On the other hand,
6d (R1 ¼ CH3), 8m (R1 ¼ H, R3 ¼ R4 ¼ C2H5), 8n (R1 ¼ H, R3 ¼ R4
¼ n-C3H7), 8q (R1 ¼ H, R3, R4 ¼ morpholin-4-yl), 8r (R1 ¼ H, R3,
R4 ¼ 1H-imidazol-1-yl), 8t (R1 ¼ CH3, R3 ¼ R4 ¼ n-C3H7), 8u (R1
¼ CH3, R3, R4 ¼ pyrrolidin-1-yl), and 8x (R1 ¼ CH3, R3, R4 ¼ 1H-
imidazol-1-yl) displayed 83% anticonvulsant activity at 0.087,
0.033, 0.035, 0.025, 0.033, 0.035, 0.046, and 0.032 mmol/kg
dose levels, respectively. The anticonvulsant potential of the
It was proven that PTZ-induced seizures could be controlled
by drugs that reduce T-type Ca2þ currents and also by those
which enhance gamma amino butyric acid type A (GABAA)
receptor-mediated inhibitory neurotransmission [27–30]. As
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Table 1. Anticonvulsant activity and neurotoxicity of compounds 6a–d and 8a–x as well as the reference drugs against
pentylenetetrazole and electro-induced seizures in adult male albino mice.
Maximum %
ED50 mg/kg
protection
(confidence limits)
ED50 mmol/kg
(confidence limits)
Dosea) mg/kg
(mmol/kg)
Compd.
6a
scPTZ
MES
Neurotoxicityb)
34 (0.147)
100
50
0/6
23 (27.67–19.12)
0.1 (0.12–0.083)
6b
8a
28 (0.11)
31 (0.09)
83
83
16
100
0/6
0/6
nd
26 (28.29–23.89)c)
0.075 (0.082–0.069)
8b
8c
30 (0.08)
28 (0.08)
100
100
33
66
0/6
0/6
24 (26.29–21.90)
0.064 (0.071–0.059)
20 (24.42–16.38)
0.058 (0.071–0.48)
8d
8e
8f
33 (0.092)
33 (0.092)
37 (0.11)
66
83
100
83
16
16
0/6
0/6
0/6
nd
nd
24 (28.86–19.96)
0.07 (0.085–0.059)
8g
8h
8i
8j
8k
8l
28 (0.078)
26 (0.067)
28 (0.078)
36 (0.097)
30 (0.08)
32 (0.09)
50
83
83
66
83
50
33
16
50
16
33
0/6
0/6
0/6
0/6
0/6
0/6
nd
nd
nd
nd
nd
100
25 (28.53–21.91)
0.07 (0.081–0.062)
9 (11.35–7.135)
6c
18 (0.058)
100
–
0/6
0.03 (0.037–0.023)
6d
8m
8n
8o
28 (0.087)
15 (0.033)
15 (0.035)
10 (0.023)
83
83
83
33
–
0/6
0/6
0/6
0/6
nd
nd
nd
50
50
100
7 (9.11–5.38)
0.016 (0.022–0.013)
8p
8q
8r
8s
8t
8u
8v
8w
16 (0.037)
11 (0.025)
14 (0.033)
12 (0.028)
16 (0.035)
20 (0.046)
12 (0.026)
11 (0.024)
66
83
83
66
83
83
66
100
33
66
66
33
16
33
16
50
0/6
0/6
0/6
0/6
0/6
0/6
0/6
0/6
nd
nd
nd
nd
nd
nd
nd
5 (7.69–3.25)
0.011 (0.017–0.007)
nd
13.2 (15.90–6.80)
0.056 (0.068–0.029)
130 (150–111)
0.92 (1.06–0.78)
9.5 (7.8–11.6)
0.037 (0.03– 0.046)
8x
14 (0.032)
30 (0.13)
83
100
–
–
0/6
nd
Phenobarbital
Ethosuximide
150 (1.06)
45 (0.16)
100
–
nd
nd
Diphenylhydantoin
–
100
–, indicates the absence of anticonvulsant activity at the tested dose level; nd, not determined.
a)The minimal dose which exerted the maximum anticonvulsant potential.
b)Rotarod test: Number of animals exhibiting neurotoxicity/number of animals tested.
c)ED50 in MES screen.
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Arch. Pharm. Chem. Life Sci. 2015, 348, 575–588
Anticonvulsant Activity of Diazaspirodecan-4-ones
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mentioned above, as all the new screened compounds were
found to control the seizures induced by PTZ, thus this result
might speculate that these compounds probably exhibit their
anticonvulsant potential through GABA activation or influ-
ence on Ca2þ channels.
mixture was cooled to 0ꢀ5°C and 14.5 g (0.066 mol) of di-tert-
butyl dicarbonate (Boc)2O was added portionwise. The
reaction mixture was stirred at room temperature for 15 h.
The pH was adjusted to 3 with 2 M HCl, extracted with DCM,
dried over anhydrous Na2SO4, and evaporated under reduced
pressure to give 10.4 g (65%) yield of 4 as white solid, m.p.
176ꢀ178°C (Ref. [24], m.p. 177ꢀ178°C).
Conclusion
General procedure for synthesis of 1-amino-N-substituted
cyclohexanecarboxamides (5a and 5b)
The anticonvulsant potential of certain substituted-1,3-
diazaspiro[4.5]decan-4-ones 6a–d and 8a–x was investigated.
Most of the compounds displayed 50–100% anticonvulsant
activity in the scPTZ screen at a dose range from 0.023 to
0.147 mmol/kg. The most potent compounds in the scPTZ
screen were 8w (ED50 ¼ 0.011 mmol/kg), 8o (ED50 ¼ 0.016
mmol/kg), and 6c (ED50 ¼ 0.03 mmol/kg). They possessed
more potent activities which reached 1.8-, 3.5-, and 5-fold
than phenobarbital, and 30.6-, 57.5-, and 83.6-fold than
ethosuximide, respectively. Compound 8a is the only com-
pound which exhibited 100% protection in the MES screen
with an ED50 of 0.075 mmol/kg. None of the test compounds
showed any minimal motor impairment at the maximum
administered dose in the neurotoxicity screen. These com-
pounds could be regarded as promising candidates as
antiepileptic drugs.
A mixture of 4.86 g (0.02 mol) 1-[(tert-butoxycarbonyl)amino]-
cyclohexanecarboxylic acid (4) and 2.02 g (0.02 mol) of
triethylamine in 100 mL dry THF (100 mL) was stirred at 0–
5°C. After stirring for 5 min, ethylchloroformate (2.16 g,
0.02 mol) was added in one portion and immediately a white
precipitate formed. The reaction was allowed to proceed for
an additional 20 min, then a solution of 0.02 mol of either
aniline or p-toluidine in 20 mL THF was added dropwise.
The reaction mixture was stirred for an additional 18 h at
the ambient temperature and the precipitated triethylamine
hydrochloride was filtered off. The residue formed after
evaporation of solvent under reduced pressure was dissolved
in 100 mL of DCM and subjected to deprotection using
hydrogen chloride gas for 4 h followed by basification with
10% Na2CO3, extraction with DCM, and crystallization from a
mixture of petroleum ether (40–60)/ethyl acetate to give 5a
and 5b as white crystals.
Experimental
1-Amino-N-phenylcyclohexanecarboxamide (5a)
M.p. 98ꢀ100°C; yield 65%; IR (KBr, cmꢀ1): 3402–3317 (NH2),
Chemistry
–
Melting points (uncorrected) were determined by using
Electrothermal Capillary melting point apparatus. Infrared
(IR) spectra were recorded in KBr discs using a Jasco FT/IR-6100
spectrometer. 1H NMR and13C NMRspectra werecarriedout on
Jeol ECA 500MHz spectrometer and Bruker 300MHz using TMS
as internal standard and chemical shift values were recorded in
ppm on d scale. EI/MS measurements were made using Thermo
Scientific ISQ single quadrupole mass spectrometer at 70 eV
ionization energy. Elemental analyses were carried out in
Microanalytical Unit, National Research Centre and the results
were within ꢁ 0.4% of the theoretical value. Monitoring of
reactions was achieved by TLC on silica gel plates (Merck, 60F
254) and visualization was performed by illumination with UV
light source (254 nm). Column chromatography was carried out
on silica gel 60 purchased from Merck.
3229 (NH) and 1672 (C O, amide); MS (EI) m/z (%): 218 (21)
–
(Mþþ1), 98 (100); 1H NMR (CDCl3): 1.24–2.02 (m, 12H,
cyclohexyl protons, NH2), 7.02–7.6 (m, 5H, Har.), 10.09 (s, 1H,
NH); 13C NMR (CDCl3): 21.33, 25.29, 34.43 (5CH2–cyclohexyl),
57.89 (C–cyclohexyl), 119.28, 123.79, 129, 138.35 (aromatic
–
carbons), 176.4 (C O, amide). Anal. calcd. for C13H18N2O: C,
–
71.53; H, 8.31; N, 12.83. Found: C, 71.72; H, 8.13; N, 13.12.
1-Amino-N-(4-methylphenyl)cyclohexanecarboxamide
(5b)
M.p. 102ꢀ104°C; yield 63%; IR (KBr, cmꢀ1): 3395–3334 (NH2),
–
3218 (NH) and 1664 (C O, amide); MS (EI) m/z (%): 233 (4)
–
(Mþþ1), 98 (100); 1H NMR (CDCl3): 1.32–2.1 (m, 12H, cyclohexyl
protons, NH2), 2.31 (s, 3H, CH3), 7.11–7.13 (d, J ¼ 7.5 Hz, 2H,
H
ar.), 7.5–7.52 (d, J ¼ 8 Hz, 2H, Har.), 10 (s, 1H, NH); 13C NMR
(CDCl3): 20.87, 21.29, 25.21, 34.4 (5CH2–cyclohexyl, CH3), 57.81
(C–cyclohexyl), 118.98, 129.13, 133.19, 135.75 (aromatic
Synthesis of 1,3-diazaspiro[4.5]decane-2,4-dione (2)
Prepared as reported in Ref. [25].
–
carbons), 175.98 (C O, amide); Anal. calcd. for C14H20N2O:
–
C, 72.38; H, 8.68; N, 12.06. Found: C, 72.02; H, 9.03; N, 12.00.
Synthesis of 1-aminocyclohexanecarboxylic acid (3)
Prepared as reported in Ref. [31].
General procedure for the synthesis of 3-aryl-1,3-
diazaspiro[4.5]decan-4-one (6a and 6b) and 2-phenyl-3-
aryl-1,3-diazaspiro[4.5]decan-4-one (6c and 6d)
A mixture of 0.0128 mol of 1-amino-N-substituted cyclo-
hexanecarboxamides 5a or 5b, 0.0141 mol of paraformalde-
hyde or benzaldehyde and one drop of piperidine in 25 mL
Synthesis of 1-[(tert-butoxycarbonyl)amino]-
cyclohexanecarboxylic acid (4)
To a solution of 40 mL, 3.8 M NaOH was added (9.4 g,
0.066 mol) of 3 and 50 mL tetrahydrofuran. The reaction
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M. N. Aboul-Enein et al.
Archiv der Pharmazie
absolute ethanol were refluxed overnight. The solvent was
removed under vacuum, the residual oil was washed with a
solution of aqueous sodium bisulphite, extracted with DCM,
dried over Na2SO4, and evaporated under reduced pressure
to give crude solid which was purified by column chroma-
tography using silica gel as a stationary phase and a mixture
of petroleum ether (40–60)/ethyl acetate (8:2) as a mobile
phase.
General procedure for synthesis of 1-(chloroacetyl)-3-aryl-
1,3-diazaspiro[4.5]decan-4-ones (7a and 7b) and 1-
(chloroacetyl)-2-phenyl-3-aryl-1,3-diazaspiro[4.5]decan-4-
ones (7c and 7d)
Chloroacetyl chloride (6.7 g, 0.06 mol) was added dropwise to
a mixture of the appropriate amine 6a–d (0.05 mol) and
anhydrous K2CO3 (8.2 g, 0.06 mol) in 50 mL dry benzene at 0–
5°C. The reaction mixture was refluxed for 18 h, after cooling
to room temperature, the solvent was removed under vacuum
washed with 10% Na2CO3, extracted with DCM, dried over
anhydrous Na2SO4, evaporated under reduced pressure, and
crystallized from a mixture of petroleum ether (40–60)/ethyl
acetate to give 7a–d as white crystals.
3-Phenyl-1,3-diazaspiro[4.5]decan-4-one (6a)
White solid; m.p. 144ꢀ146°C; yield 80%; IR (KBr, cmꢀ1):þ3303
–
(NH) and 1685 (C O, amide); MS (EI) m/z (%): 230 (11) (M ), 98
–
(100); 1H NMR (CDCl3): 1.55–1.75 (m, 10H, cyclohexyl protons),
2.07 (s, 1H, NH), 4.77 (s, 2H, CH2–NH), 7.12–7.56 (m, 5H, Har.);
13C NMR (CDCl3): 21.71, 25.41, 31.88 (5CH2–cyclohexyl), 62.38
(CH2–NH), 63.45 (C–cyclohexyl), 118.73 (CHar), 124.5 (CHar),
1-(Chloroacetyl)-3-phenyl-1,3-diazaspiro[4.5]decan-4-one (7a)
White crystals; m.p. 156ꢀ158°C; yield 79%; IR (KBr, cmꢀ1): 1678
þ
–
–
129.09 (CH ), 138.23 (C ), 176.9 (C O, amide). Anal. calcd. for
(C O, amide); MS (EI) m/z (%): 307 (42) (M þ1), 309 (14), 271
–
–
ar
ar
C
14H18N2O: C, 73.01; H, 7.88; N, 12.16. Found: C, 72.90; H, 7.65;
(100); 1H NMR (CDCl3): 1.26–2.68 (m, 10H, cyclohexyl protons),
4.21 (s, 2H, CH2–Cl), 5.3 (s, 2H, CH2–N), 7.36–7.56 (m, 5H, Har.);
13C NMR (CDCl3): 21.78, 24.33, 29.74 (5CH2–cyclohexyl), 42.45
(CH2–Cl), 61.5, 64.43 (C–cyclohexyl, CH2–N), 120.17, 125.95,
N, 11.93.
3-(4-Methylphenyl)-1,3-diazaspiro[4.5]decan-4-one (6b)
White solid; m.p. 158ꢀ160°C; yield 82%; IR (KBr, cmꢀ1):þ3291
–
129.37, 136.33 (aromatic carbons), 163.48 (C O, amide), 171.41
–
–
–
(NH) and 1679 (C O, amide); MS (EI) m/z (%): 244 (12) (M ), 98
(C O, amide). Anal. calcd. for C16H19ClN2O2: C, 62.64; H, 6.24; N,
–
–
(100); 1H NMR (CDCl3): 1.33–1.80 (m, 10H, cyclohexyl protons),
1.99 (s, 1H, NH), 2.31 (s, 3H, CH3), 4.69 (s, 2H, CH2–NH), 7.15–
7.46 (m, 4H, Har.); 13C NMR (CDCl3): 20.92, 21.7, 25.37, 31.86
(5CH2–cyclohexyl, CH3), 62.46, 63.37 (C–cyclohexyl, CH2–NH),
118.88, 129.51, 134.17, 135.66 (aromatic carbons), 176.72
9.13. Found: C, 62.41; H, 5.87; N, 8.99.
1-(Chloroacetyl)-3-(4-methylphenyl)-1,3-diazaspiro[4.5]-
decan-4-one (7b)
White crystals; m.p. 156ꢀ158°C; yield 76%; IR (KBr, cmꢀ1):
–
–
–
–
(C O, amide). Anal. calcd. for C15H20N2O: C, 73.74; H, 8.25; N,
1697 (C O, amide) and 1669 (C O, amide); MS (EI) m/z (%):
–
–
11.47. Found: C, 73.51; H, 7.91; N, 11.09.
320 (2.71) (Mþ), 322 (0.91), 91 (100); 1H NMR (CDCl3): 1.27–2.14
(m, 8H, cyclohexyl protons), 2.38 (s, 3H, CH3), 2.71–2.75 (m, 2H,
cyclohexyl protons), 4.06 (s, 2H, CH2–Cl), 5.33 (s, 2H, CH2–N),
7.23–7.51 (m, 4H, Har.); 13C NMR (CDCl3): 20.94, 21.73, 24.28,
29.7 (5CH2–cyclohexyl, CH3), 42.28 (CH2–Cl), 61.60, 64.34
(C–cyclohexyl, CH2–N), 120.24, 129.83, 133.68, 135.82 (aro-
2,3-Diphenyl-1,3-diazaspiro[4.5]decan-4-one (6c)
White solid; m.p. 114ꢀ116°C; yield 77%; IR (KBr, cmꢀ1): 33þ43
–
(NH) and 1686 (C O, amide); MS (EI) m/z (%): 306 (26) (M ),
–
187 (100); 1H NMR (CDCl3): 1.25–2.12 (m, 11H, cyclohexyl
protons, NH), 5.97 (s, 1H, CH–NH), 7.22–7.34 (m, 10H, Har.);
13C NMR (CDCl3): 21.57, 21.79, 25.33, 31.55, 34.92
(5CH2–cyclohexyl), 63.02, 75.45 (C–cyclohexyl, CH–NH),
122.26, 125.15, 127.07, 128.77, 129.14, 129.23, 137.4, 139.03
–
–
matic carbons), 163.44 (C O, amide), 171.34 (C O, amide).
–
–
Anal. calcd. for C17H21ClN2O2: C, 63.64; H, 6.60; N, 8.73. Found:
C, 63.41; H, 6.42; N, 8.56.
–
(aromatic carbons), 177.68 (C O, amide). Anal. calcd. for
1-(Chloroacetyl)-2,3-diphenyl-1,3-diazaspiro[4.5]decan-4-
–
C
20H22N2O: C, 78.40; H, 7.24; N, 9.14. Found: C, 78.13; H, 6.84;
one (7c)
N, 8.99.
White crystals; m.p. 194ꢀ196°C; yield 77%; IR (KBr, cmꢀ1):
þ
–
1684 (C O, amide); MS (EI) m/z (%): 382 (3) (M ), 384 (1), 28
–
3-(4-Methylphenyl)-2-phenyl-1,3-diazaspiro[4.5]decan-4-
one (6d)
(100); 1H NMR (CDCl3): 1.35–2.24 (m, 10H, cyclohexyl protons),
3..46–3.74 (m, 2H, CH2–Cl), 6.52 (s, 1H, CH–N), 7.23–7.29 (m,
10H, Har.); 13C NMR (CDCl3): 22.04, 22.31, 24.39, 29.92, 31.49
(5CH2–cyclohexyl), 43.64 (CH2–Cl), 64.55, 75.73 (C–cyclohexyl,
CH–N), 126.52, 127.32, 127.68, 129.21, 129.4, 130.18, 134.43,
White solid; m.p. 126ꢀ128°C; yield 73%; IR (KBr, cmꢀ1): 33þ05
–
(NH) and 1678 (C O, amide); MS (EI) m/z (%): 320 (11) (M ),
–
187 (100); 1H NMR (CDCl3): 1.39–2.15 (m, 11H, cyclohexyl
protons, NH), 2.24 (s, 3H, CH3), 5.95 (s, 1H, CH–NH), 7.04–7.06
(d, J ¼ 7.5 Hz, 2H, Har.), 7.22–7.23 (d, J ¼ 8 Hz, 2H, Har.), 7.3–7.4
(m, 5H, Har.); 13C NMR (CDCl3): 20.9, 21.53, 21.74, 25.29, 31.48,
34.88 (5CH2–cyclohexyl, CH3), 62.89 (C–cyclohexyl), 75.48
(CH–NH), 122.28, 127.05, 129.04, 129.12, 129.32, 134.73,
–
–
137.56 (aromatic carbons), 164.71 (C O, amide), 171.25 (C O,
–
–
amide). Anal. calcd. for C22H23ClN2O2: C, 69.01; H, 6.05; N,
7.32. Found: C, 68.72; H, 5.68; N, 7.14.
1-(Chloroacetyl)-3-(4-methylphenyl)-2-phenyl-1,3-
–
134.8, 139.14 (aromatic carbons), 177.59 (C O, amide). Anal.
diazaspiro[4.5]decan-4-one (7d)
–
calcd. for C21H24N2O: C, 78.71; H, 7.55; N, 8.74. Found: C, 78.41;
H, 7.91; N, 8.58.
White crystals; m.p. 174ꢀ176°C; yield 79%; IR (KBr, cmꢀ1):
þ
–
1680 (C O, amide); MS (EI) m/z (%): 396 (17) (M ), 398 (5), 361
–
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Anticonvulsant Activity of Diazaspirodecan-4-ones
Archiv der Pharmazie
(100); 1H NMR (CDCl3): 1.29–1.82 (m, 8H, cyclohexyl protons),
2.29 (s, 3H, CH3), 2.93 (m, 2H, cyclohexyl protons), 3.5–3.81 (m,
2H, CH2–Cl), 6.51 (s, 1H, CH–N), 6.94–7.35 (m, 9H, Har.);
13C NMR (CDCl3): 21.07, 21.99, 22.24, 24.33, 29.98, 31.88
(5CH2–cyclohexyl, CH3), 43.54 (CH2–Cl), 64.41, 75.21
(C–cyclohexyl, CH–N), 126.31, 127.27, 129.3, 129.79, 129.4,
C–cyclohexyl), 119.64, 125.34, 129.18, 136.8 (aromatic car-
–
–
bons), 168.18 (C O, amide), 171.88 (C O, amide). Anal. calcd.
–
–
for C22H33N3O2: C, 71.12; H, 8.95; N, 11.31. Found: C, 70.82; H,
9.15; N, 11.29.
3-Phenyl-1-(pyrrolidin-1-ylacetyl)-1,3-diazaspiro[4.5]-
decan-4-one (8c)
Purified by column chromatography using a mixture of
–
130.04, 131.66, 137.66 (aromatic carbons), 164.65 (C O,
–
–
amide), 171.22 (C O, amide). Anal. calcd. for C23H25ClN2O2:
–
C, 69.60; H, 6.35; N, 7.06. Found: C, 69.45; H, 6.02; N, 6.81.
petroleum ether (40–60)/ethyl acetate 7:3 as a mobile phase,
yield 60%, m.p. 112ꢀ114°C, IR (KBr, cmꢀ1): 1708 (C O, amide)
–
–
þ
–
General procedure for synthesis of 1-(aminoacetyl)-3-aryl-
1,3-diazaspiro[4.5]decan-4-ones (8a–l) and 1-
(aminoacetyl)-2-phenyl-3-aryl-1,3-diazaspiro[4.5]decan-4-
ones (8m–x)
A mixture of 0.002 mol of the chloroacetylated derivative 7a–
d and 0.01 mol of the appropriate amine in 40 mL toluene was
heated at 90°C for 20 h. After cooling to room temperature,
the solvent was removed under reduced pressure to give a
residual oil which was washed with water and extracted with
DCM to give the target compounds 8a–x in crude form which
were purified by crystallization or by column chromatography
using silica gel as a stationary phase.
and 1660 (C O, amide); MS (EI) m/z (%): 342 (5.43) (M þ1), 84
–
(100); 1H NMR (CDCl3): 1.23–2.06 (m, 12H), 2.14-2.75 (m, 6H)
(cyclohexyl protons, pyrrolidine protons), 3.26 (s, 2H,
CH2–C¼O), 5.35 (s, 2H, CH2–N), 7.18–7.57 (m, 5H, Har.);
13C NMR (CDCl3): 21.89, 23.79, 24.42, 29.88 (5CH2–cyclohexyl,
2CH2–pyrrolidine), 54.2 (2CH2–pyrrolidine), 60.18, 61.34, 64.03
–
(CH –C O, C–cyclohexyl, CH –N), 119.97, 125.6, 129.28, 136.69
–
2
2
–
–
(aromatic carbons), 167.63 (C O, amide), 172.01 (C O,
–
–
amide). Anal. calcd. for C20H27N3O2: C, 70.35; H, 7.97; N,
12.31. Found: C, 70.63; H, 8.21; N, 12.56.
3-Phenyl-1-(piperidin-1-ylacetyl)-1,3-diazaspiro[4.5]-
decan-4-one (8d)
1-[(Diethylamino)acetyl]-3-phenyl-1,3-diazaspiro[4.5]-
decan-4-one (8a)
Purified by column chromatography using a mixture of
Crystallized from a mixture of petroleum ether (40–60)/ethyl
acetate, yield 63%, m.p. 138ꢀ140°C, IR (KBr, cmꢀ1): 1706 (C O,
–
–
–
amide) and 1644 (C O, amide); MS (EI) m/z (%): 356 (1.76)
–
petroleum ether (40–60)/ethyl acetate 6:4 as a mobile phase,
(Mþþ1), 98 (100); 1H NMR (CDCl3): 1.28–1.45 (m, 3H), 1.58–1.76
(m, 9H), 2.02–2.12 (m, 2H) (cyclohexyl protons and piperidine
protons), 2.48 (br s, 4H, piperidine protons), 2.75–2.81 (m, 2H,
yield 75%, m.p. 98ꢀ100°C, IR (KBr, cmꢀ1): 1711 (C O, amide)
–
–
þ
–
and 1646 (C O, amide); MS (EI) m/z (%): 344 (0.75) (M þ1), 86
–
(100); 1H NMR (CDCl3): 1.03–1.05 (t, J ¼ 6.7 Hz, 6H, (CH2–CH3)2),
1.3–2.06 (m, 8H, cyclohexyl protons), 2.58–2.59 (q, J ¼ 6.7 Hz,
4H, (CH2–CH3)2), 2.71–2.76 (m, 2H, cyclohexyl protons), 3.22 (s,
cyclohexyl protons), 3.12 (s, 2H,CH –C O), 5.43 (s, 2H, CH –N),
–
–
2
2
7.19–7.22 (m, 1H, Har.), 7.38–7.42 (m, 2H, Har.), 7.59–7.61 (m, 2H,
H
ar.); 13C NMR (CDCl3): 21.8, 23.88, 24.36, 25.92, 29.77 (5CH2
–
2H,CH –C O), 5.46 (s, 2H, CH –N), 7.16 (m, 1H, Har.), 7.36–7.57
cyclohexyl, 3CH2 piperidine), 54.57 (2CH2–piperidine), 61.33,
–
2
2
(m, 4H, Har.); 13C NMR (CDCl3): 11.78 (2CH2–CH3), 21.87, 24.42,
63.85, 64.03 (CH –C O, CH –N and C–cyclohexyl), 119.74,
–
–
2
2
–
–
29.78 (5CH –cyclohexyl), 47.8 (2CH –CH ), 58.95 (CH –C O),
125.42, 129.19,136.71 (aromaticcarbons), 167.27 (C O, amide),
–
–
2
2
3
2
–
61.56, 64.12 (C–cyclohexyl, CH2–N), 119.6, 125.4, 129.27,
171.88 (C O, amide). Anal. calcd. for C21H29N3O2: C, 70.95; H,
–
–
136.85 (aromatic carbons), 168.27 (C O, amide), 171.93
8.22; N, 11.82. Found: C, 70.69; H, 8.53; N, 11.73.
–
–
(C O, amide). Anal. calcd. for C20H29N3O2: C, 69.94; H, 8.51;
–
N, 12.23. Found: C, 69.59; H, 8.49; N, 12.02.
1-(Morpholin-4-ylacetyl)-3-phenyl-1,3-diazaspiro[4.5]-
decan-4-one (8e)
1-[(Dipropylamino)acetyl]-3-phenyl-1,3-diazaspiro[4.5]-
decan-4-one (8b)
Purified by column chromatography using a mixture of
Crystallized from a mixture of petroleum ether (40–60)/ethyl
acetate, yield 60%, m.p. 142ꢀ144°C, IR (KBr, cmꢀ1): 1710
–
–
–
(C O, amide) and 1683 (C O, amide); MS (EI) m/z (%): 358
–
petroleum ether (40–60)/ethyl acetate 7:3 as a mobile phase,
(0.67) (Mþþ1), 100 (100); 1H NMR (CDCl3): 1.23–1.36 (m, 1H,
cyclohexyl proton), 1.65–1.77 (m, 5H, cyclohexyl protons),
2.03–2.12 (m, 2H, cyclohexyl protons), 2.59 (s, 4H, morpholine
protons), 2.74–2.8 (m, 2H, cyclohexyl protons), 3.18 (s, 2H,
yield 70%, m.p. 80ꢀ82°C, IR (KBr, cmꢀ1): 1714 (C O, amide)
–
–
þ
–
–
and 1647 (C O, amide); MS (EI) m/z (%): 371 (15) (M ), 114
(100); 1H NMR (CDCl3): 0.89–0.92 (t, J ¼ 7.5 Hz, 6H,
(CH2–CH2–CH3)2), 1.33–1.35 (m, 1H, cyclohexyl proton),
1.47–1.55 (m, 4H, (CH2–CH2–CH3)2), 1.65–1.78 (m, 5H, cyclo-
hexyl protons), 2.09–2.11 (m, 2H, cyclohexyl protons), 2.48–
2.51 (t, J ¼ 7.5 Hz, 4H, (CH2–CH2–CH3)2), 2.76–2.82 (m, 2H,
–
–
CH –C O), 3.74–3.76 (t, J ¼ 4.5, 4H, morpholine protons),
2
5.38 (s, 2H, CH2–N), 7.21–7.28 (m, 1H, Har.), 7.4–7.43 (m, 2H,
H
ar.), 7.58–7.6 (m, 2H, Har.); 13C NMR (CDCl3): 21.76, 24.32,
29.83 (5CH2–cyclohexyl), 53.68 (2CH2–morpholine), 61.24,
–
–
cyclohexyl protons), 3.27 (s, 2H,CH –C O), 5.52 (s, 2H, CH –N),
62.57, 64.11 (CH –C O, CH2–N, C–cyclohexyl), 66.71
–
–
2
2
2
7.19–7.22 (m, 1H, Har.), 7.39–7.42 (m, 2H, Har.), 7.59–7.61
(m, 2H, Har.); 13C NMR (CDCl3): 11.98 (2CH2–CH2–CH3), 19.98,
21.8, 24.35, 29.72 (2CH2–CH2–CH3, 5CH2–cyclohexyl) 56.54
(2CH2–morpholine), 119.9, 125.64, 129.25, 136.53 (aromatic
–
–
carbons), 166.29 (C O, amide), 171.71 (C O, amide). Anal.
–
–
calcd. for C20H27N3O3: C, 67.20; H, 7.61; N, 11.76. Found: C,
67.48; H, 7.24; N, 11.57.
–
(2CH2–CH2–CH3), 60.64, 61.49, 64.04 (CH –C O, CH2–N,
–
2
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M. N. Aboul-Enein et al.
Archiv der Pharmazie
–
–
–
1-(1H-Imidazol-1-ylacetyl)-3-phenyl-1,3-diazaspiro[4.5]-
decan-4-one (8f)
Purified by column chromatography using a mixture of
(C O, amide) and 1656 (C O, amide); MS (EI) m/z (%): 355
–
(0.04) (Mþ), 84 (100); 1H NMR (CDCl3): 1.3–1.33 (m, 1H), 1.63–
1.8 (m, 9H) (cyclohexyl protons, pyrrolidine protons), 2.07–
2.09 (m, 2H, cyclohexyl protons), 2.33 (s, 3H, CH3), 2.64 (br s,
4H, pyrrolidine protons), 2.75–2.79 (m, 2H, cyclohexyl
chloroform/ethyl acetate/methanol 7:5:1 as a mobile phase,
yield 73%, m.p. 202ꢀ204°C, IR (KBr, cmꢀ1): 1705 (C O, amide)
–
–
þ
–
–
–
–
and 1679 (C O, amide); MS (EI) m/z (%): 338 (1.79) (M ), 81
protons), 3.3 (s, 2H,CH –C O), 5.34 (s, 2H, CH –N), 7.18–7.19
2
2
(100); 1H NMR (CDCl3): 1.17–2.63 (m, 10H, cyclohexyl protons),
(d, J ¼ 8 Hz, 2H, Har.), 7.45–7.46 (d, J ¼ 8 Hz, 2H, Har.), 13C NMR
(CDCl3): 20.88, 21.81, 23.75, 24.37, 29.82 (5CH2–cyclohexyl,
CH3, 2CH2–pyrrolidine), 54.05 (2CH2–pyrrolidine), 59.90,
–
4.72 (s, 2H,CH –C O), 5.22 (s, 2H, CH –N), 6.92 (s, 1H,
–
2
2
imidazole), 7.02 (s, 1H, imidazole), 7.19–7.54 (m, 6H, Har.
,
imidazole); 13C NMR (CDCl3): 21.78, 24.3, 30.02
61.41, 63.89 (CH –C O, C–cyclohexyl, CH2–N), 120.07,
–
–
2
–
–
(5CH –cyclohexyl), 48.77 (CH –C O), 61.06, 64.5 (C–cyclohexyl,
129.67, 134.08, 135.31 (aromatic carbons), 167.36 (C O,
–
–
2
2
–
CH2–N), 120.3, 120.49, 126.12, 129.43, 136.2, 138.18 (aromatic
amide), 171.73 (C O, amide). Anal. calcd. for C21H29N3O2: C,
–
–
–
and imidazole carbons), 163.58 (C O, amide), 171.28 (C O,
70.95; H, 8.22; N, 11.82. Found: C, 70.60; H, 7.97; N, 11.72.
–
–
amide). Anal. calcd. for C19H22N4O2: C, 67.44; H, 6.55; N, 16.56.
Found: C, 67.67; H, 6.75; N, 16.78.
3-(4-Methylphenyl)-1-(piperidin-1-ylacetyl)-1,3-
diazaspiro[4.5]decan-4-one (8j)
1-[(Diethylamino)acetyl]-3-(4-methylphenyl)-1,3-
diazaspiro[4.5]decan-4-one (8g)
Crystallized from a mixture of petroleum ether (40–60)/ethyl
acetate, yield 60%, m.p. 156ꢀ158°C, IR (KBr, cmꢀ1): 1706
–
–
–
Crystallized from a mixture of petroleum ether (40–60)/ethyl
(C O, amide) and 1654 (C O, amide); MS (EI) m/z (%): 370
–
acetate, yield 70%, m.p. 102ꢀ104°C, IR (KBr, cmꢀ1): 1706
(1.5) (Mþþ1), 98 (100); 1H NMR (CDCl3): 1.31–1.45 (m, 3H), 1.6–
1.77 (m, 9H), 2.05–2.13 (m, 2H) (cyclohexyl protons and
piperidine protons), 2.35 (s, 3H, CH3), 2.49 (br s, 4H, piperidine
protons), 2.75–2.81 (m, 2H, cyclohexyl protons), 3.13 (s, 2H,
–
–
–
(C O, amide) and1650 (C O, amide);MS (EI)m/z(%): 358(1.26)
–
(Mþþ 1), 86 (100); 1H NMR (CDCl3): 1.07–1.11 (t, J ¼ 6 Hz, 6H,
(CH2–CH3)2), 1.3–2.14 (m, 8H, cyclohexyl protons), 2.36 (s, 3H,
CH3), 2.59–2.65 (q, J ¼ 6 Hz, 4H, (CH2–CH3)2), 2.76–2.8 (m, 2H,
CH –C O), 5.4 (s, 2H, CH –N), 7.2–7.48 (m, 4H, Har.); 13C NMR
–
–
2
2
–
cyclohexyl protons), 3.25 (s, 2H,CH –C O), 5.49 (s, 2H, CH –N),
(CDCl3): 20.92, 21.82, 23.86, 24.38, 25.89, 29.8 (5CH2 cyclo-
hexyl, 3CH2 piperidine, CH3), 54.56 (2CH2–piperidine), 61.46,
–
2
2
7.21–7.51 (m, 4H, Har.); 13C NMR (CDCl3): 7.3 (2CH2–CH3), 16.4,
17.37, 19.93, 25.28 (5CH2–cyclohexyl, CH3), 43.26 (2CH2–CH3),
–
63.42, 64.01 (CH –C O, CH –N, C–cyclohexyl), 119.92, 129.71,
–
2
2
–
–
54.74 (CH –C O), 57.19, 59.54 (C–cyclohexyl, CH –N), 115.26,
134.13, 135.29 (aromatic carbons), 167.2 (C O, amide), 171.74
–
–
2
2
–
–
125.23, 129.85,130.66 (aromaticcarbons), 163.89 (C O, amide),
(C O, amide). Anal. calcd. for C22H31N3O2: C, 71.51; H, 8.46; N,
–
–
–
167.28 (C O, amide). Anal. calcd. for C21H31N3O2: C, 70.55; H,
11.37. Found: C, 71.20; H, 8.12; N, 11.05.
–
8.74; N, 11.75. Found: C, 70.25; H, 8.65; N, 11.52.
3-(4-Methylphenyl)-1-(morpholin-4-ylacetyl)-1,3-
diazaspiro[4.5]decan-4-one (8k)
Purified by column chromatography using a mixture of
1-[(Dipropylamino)acetyl]-3-(4-methylphenyl)-1,3-
diazaspiro[4.5]decan-4-one (8h)
Purified by column chromatography using a mixture of
petroleum ether (40–60)/ethyl acetate 6:4 as a mobile phase,
petroleum ether (40–60)/ethyl acetate 7:3 as a mobile phase,
yield 62%, m.p. 182ꢀ184°C, IR (KBr, cmꢀ1): 1703 (C O, amide)
–
–
yield 63%, viscous oil, IR (KBr, cmꢀ1): 1682 (C O, amide); MS
and 1650 (C O, amide); MS (EI) m/z (%): 372 (0.28) (M þ1),
þ
–
–
–
–
(EI) m/z (%): 386 (1.52) (Mþþ1), 114 (100); 1H NMR (CDCl3):
0.83–0.86 (t, J ¼ 7.65 Hz, 6H, (CH2–CH2–CH3)2), 1.27–1.3 (m, 1H,
cyclohexyl proton), 1.42–1.48 (m, 4H, (CH2–CH2–CH3)2), 1.65–
1.72 (m, 5H, cyclohexyl protons), 2.09–2.11 (m, 1H, cyclohexyl
protons), 2.29 (s, 3H, CH3), 2.4–2.43 (t, J ¼ 7.65 Hz, 4H,
(CH2–CH2–CH3)2), 2.71–2.75 (m, 2H, cyclohexyl protons), 3.19
100 (100); 1H NMR (CDCl3): 1.29–1.32 (m, 1H, cyclohexyl
proton), 1.63–1.76 (m, 5H, cyclohexyl protons), 2.03–2.08
(m, 2H, cyclohexyl protons), 2.34 (s, 3H, CH3), 2.57 (s, 4H,
morpholine protons), 2.72–2.78 (m, 2H, cyclohexyl protons),
–
–
3.16 (s, 2H,CH –C O), 3.72–3.74 (t, J ¼ 4.5, 4H, morpholine
2
protons), 5.36 (s, 2H, CH2–N), 7.19–7.46 (m, 4H, Har.); 13C NMR
(CDCl3): 20.92, 21.78, 24.34, 29.84 (5CH2–cyclohexyl, CH3),
–
(s, 2H, CH –C O), 5.43 (s, 2H, CH –N), 7.15–7.43 (m, 4H, Har.);
–
2
2
13C NMR (CDCl3): 12.11 (2CH2–CH2–CH3), 20.05, 20.98, 21.89,
24.44, 29.76 (2CH2–CH2–CH3, 5CH2–cyclohexyl, CH3), 56.54
53.68 (2CH2–morpholine), 61.35, 62.5, 64.04 (CH –C O,
–
–
2
CH2–N, C–cyclohexyl), 66.71 (2CH2–morpholine), 120.06,
–
–
(2CH2–CH2–CH3), 60.81, 61.65, 64.02 (CH –C O, CH2–N,
129.74, 133.94, 135.5 (aromatic carbons), 166.28 (C O,
–
–
2
–
C–cyclohexyl), 119.79, 129.77, 134.25, 135.22 (aromatic
amide), 171.56 (C O, amide). Anal. calcd. for C21H29N3O3: C,
–
–
–
carbons), 168.42 (C O, amide), 171.8 (C O, amide). Anal.
67.90; H, 7.87; N, 11.31. Found: C, 67.53; H, 7.53; N, 11.18.
–
–
calcd. for C23H35N3O2: C, 71.65; H, 9.15; N, 10.90. Found: C,
71.88; H, 9.43; N, 11.23.
1-(1H-Imidazol-1-ylacetyl)-3-(4-methylphenyl)-1,3-
diazaspiro[4.5]decan-4-one (8l)
3-(4-Methylphenyl)-1-(pyrrolidin-1-ylacetyl)-1,3-
diazaspiro[4.5]decan-4-one (8i)
Purified by column chromatography using a mixture of
chloroform/ethyl acetate/methanol 7:5:1 as a mobile phase,
yield 70%, m.p. 172ꢀ174°C, IR (KBr, cmꢀ1): 1704 (C O, amide)
–
Crystallized from a mixture of petroleum ether (40–60)/ethyl
–
acetate, yield 75%, m.p. 136ꢀ138°C, IR (KBr, cmꢀ1): 1713
and 1675 (C O, amide); MS (EI) m/z (%): 352 (0.4) (M ), 81
þ
–
–
ß 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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Anticonvulsant Activity of Diazaspirodecan-4-ones
Archiv der Pharmazie
(100); 1H NMR (CDCl3): 1.19–2.02 (m, 8H, cyclohexyl protons),
2.3 (s, 3H, CH3), 2.6–2.62 (m, 2H, cyclohexyl protons), 4.75 (s,
H
ar.); 13C NMR (CDCl3): 22.12, 22.39, 23.79, 24.46, 30.1, 31.64
(5CH2–cyclohexyl, 2CH2–pyrrolidine), 53.76 (2CH2–pyrrolidine),
60.42, 64.24, 75.66 (CH –C O, C–cyclohexyl, CH–N), 126.30,
–
–
2H,CH –C O), 5.23 (s, 2H, CH -N), 6.94 (s, 1H, imidazole), 7.02
–
–
2
2
2
(s, 1H, imidazole), 7.16–7.18 (d, J ¼ 7.65 Hz, 2H, Har.), 7.41–7.42
(d, J ¼ 7.65 Hz, 2H, Har.), 7.52 (s, 1H, imidazole); 13C NMR
(CDCl3): 21.04, 21.8, 24.32, 30.04 (CH3, 5CH2–cyclohexyl), 48.87
127.32, 127.6, 128.93, 129.07, 129.57, 134.78, 138.26 (aromatic
–
–
carbons), 168.36 (C O, amide), 171.63 (C O, amide). Anal.
–
–
calcd.forC26H31N3O2:C,74.79;H,7.48;N,10.06.Found:C,74.50;
H, 7.10; N, 9.82.
–
(CH –C O), 61.23, 64.5 (C–cyclohexyl, CH –N), 120.45, 120.66,
–
2
2
128.82, 129.95, 133.56, 136.07, 138.16 (aromatic and imidaz-
–
–
ole carbons), 163.56 (C O, amide), 171.19 (C O, amide). Anal.
2,3-Diphenyl-1-(piperidin-1-ylacetyl)-1,3-diazaspiro[4.5]-
decan-4-one (8p)
–
–
calcd. for C20H24N4O2: C, 68.16; H, 6.86; N, 15.90. Found: C,
67.87; H, 6.55; N, 15.78.
Crystallized from a mixture of petroleum ether (40–60)/ethyl
acetate, yield 50%, m.p. 150ꢀ152°C, IR (KBr, cmꢀ1): 1701 (C O,
–
–
–
1-[(Diethylamino)acetyl]-2,3-diphenyl-1,3-diazaspiro[4.5]-
decan-4-one (8m)
Purified by column chromatography using a mixture of
amide) and 1658 (C O, amide); MS (EI) m/z (%): 432 (2.88)
–
(Mþþ1), 98 (100); 1H NMR (CDCl3): 1.24–1.46 (m, 3H), 1.6–1.79
(m, 8H), 2.09–2.17 (m, 1H), 2.24–2.26 (m, 4H), 2.39 (brs, 2H),
2.54–2.56 (m, 1H), 2.78–2.81 (m, 1H) (cyclohexyl protons and
piperidinyl protons), 2.94–2.96 (m, 1H), 3.09–3.15 (m, 1H)
petroleum ether (40–60)/ethyl acetate 6:4 as a mobile phase,
yield 67%, m.p. 130ꢀ132°C, IR (KBr, cmꢀ1): 1690 (C O, amide)
–
–
þ
and 1669 (C O, amide); MS (EI) m/z (%): 420 (1.02) (M þ1), 86
(CH –C O), 7.11–7.29 (m, 11H, CH–N, Har.); 13C NMR (CDCl3):
–
–
–
–
2
(100);1HNMR(CDCl3):0.94–0.96(t,J ¼ 6 Hz,6H,(CH2–CH3)2),1.4–
21.06, 22.07, 22.34, 23.9, 24.41, 26.03, 29.99, 31.6
(5CH2–cyclohexyl, 3CH2–piperidinyl), 54.09 (2CH2–piperidinyl),
2.25 (m, 8H, cyclohexyl protons), 2.50–2.56 (q, J ¼ 6 Hz, 4H,
–
–
–
(CH –CH ) ), 2.85–3.09 (m, 4H, cyclohexyl protons, CH –C O),
64.17, 64.47, 75.25 (CH –C O, CH –N, C–cyclohexyl), 126.2,
–
2
3 2
2
2
2
7.01(s,1H,CH-N),7.09–7.28(m,10H, Har.);13CNMR(CDCl3):11.45
(2CH2–CH3), 22.11, 22.33, 24.4, 30.45, 31.72 (5CH2–cyclohexyl),
127.22, 127.51, 128.76, 129.03, 129.38, 134.8, 138.22 (aromatic
–
–
carbons), 168.63 (C O, amide), 171.58 (C O, amide). Anal.
–
–
–
46.63 (2CH –CH ), 59.17 (CH –C O), 64.03, 75.5 (C–cyclohexyl,
calcd. for C27H33N3O2: C, 75.14; H, 7.71; N, 9.74. Found: C, 75.23;
H, 7.45; N, 9.50.
–
2
3
2
CH–N), 126.48, 127.29, 128.77, 129.04, 129.35, 134.85, 138.33
–
–
(aromatic carbons), 169.59 (C O, amide), 171.65 (C O, amide).
–
–
Anal. calcd. for C26H33N3O2: C, 74.43; H, 7.93; N, 10.02. Found: C,
74.12; H, 7.74; N, 9.85.
2,3-Diphenyl-1-(morpholin-4-ylacetyl)-1,3-diazaspiro[4.5]-
decan-4-one (8q)
Crystallized from a mixture of petroleum ether (40–60)/ethyl
–
2,3-Diphenyl-1-[(dipropylamino)acetyl]-1,3-
diazaspiro[4.5]decan-4-one (8n)
Purified by column chromatography using a mixture of
acetate, yield 60%, m.p. 168ꢀ170°C, IR (KBr, cmꢀ1): 1707 (C O,
–
þ
–
–
amide) and 1663 (C O, amide); MS (EI) m/z (%): 434 (2) (M þ1),
100 (100); 1H NMR (CDCl3): 1.26–1.43 (m, 1H, cyclohexyl proton),
1.68–1.79(m, 4H, cyclohexyl proton), 2.04–2.26(m, 3H, cyclohexyl
protons) 2.384 (br s, 2H, morpholine protons), 2.43 (br s, 2H,
morpholine protons), 2.57–2.6 (m, 1H, cyclohexyl proton), 2.87–
petroleum ether (40–60)/ethyl acetate 7:3 as a mobile phase,
yield 65%, m.p. 138ꢀ140°C, IR (KBr, cmꢀ1): 1691 (C O, amide)
–
–
þ
–
and1659(C O,amide);MS(EI)m/z(%):447(16)(M ),114(100);
–
1H NMR (CDCl3): 0.83–0.85 (t, J ¼ 6.4 Hz, 6H, (CH2–CH2–CH3)2),
1.34–2.42 (m, 16H) (cyclohexyl protons, (CH2–CH2–CH3)2,
(CH2–CH2–CH3)2), 2.77–2.93 (m, 4H) (cyclohexyl protons,
3.07 (m, 3H, cyclohexyl proton, CH –C O), 3.71–3.79 (m, 4H,
–
–
2
morpholine protons), 6.92 (s, 1H, CH–N), 7.07–7.29 (m, 10H, Har.);
13C NMR (CDCl3): 22.06, 22.3, 24.38, 30.22, 31.56
(5CH2–cyclohexyl), 53.39 (2CH2–morpholine), 63.52, 64.15,
CH –C O), 7.05–7.3 (m, 11H, CH–N, Har.); 13C NMR (CDCl3):
–
–
2
–
10.21 (2CH2–CH2–CH3), 17.99, 20.45, 24.56, 22.68, 28.38, 29.96
(2CH2–CH2–CH3, 5CH2–cyclohexyl), 53.87 (2CH2–CH2–CH3), 59
66.86, 75.63 (CH –C O, CH –N, 2CH –morpholine, C–cyclohexyl),
–
2
2
2
126.35, 127.4, 127.6 128.92, 129.09, 129.59, 134.68, 138.08
–
–
–
(CH –C O), 62.34, 75.33 (C–cyclohexyl, CH-N), 124.91, 125.49,
(aromatic carbons), 167.85 (C O, amide), 171.47 (C O, amide).
–
–
–
2
125.71, 127.07, 127.39, 127.65, 133.09, 136.56 (aromatic
Anal. calcd. for C26H31N3O3: C, 72.03; H, 7.21; N, 9.69. Found: C,
71.75; H, 7.59; N, 9.62.
–
–
–
carbons), 168.04 (C O, amide), 169.95 (C O, amide). Anal.
–
calcd. for C28H37N3O2: C, 75.13; H, 8.33; N, 9.39. Found: C, 74.81;
H, 8.02; N, 8.99.
2,3-Diphenyl-1-(1H-imidazol-1-ylacetyl)-1,3-
diazaspiro[4.5]decan-4-one (8r)
2,3-Diphenyl-1-(pyrrolidin-1-ylacetyl)-1,3-diazaspiro[4.5]-
decan-4-one (8o)
Purified by column chromatography using a mixture of
Purified by column chromatography using a mixture of
chloroform/ethyl acetate/methanol 7:5:3 as a mobile phase
followed by crystallization from mixture of ethyl acetate/
isopropanol, yield 65%, m.p. 104ꢀ106°C, IR (KBr, cmꢀ1): 1682
methylene chloride/ethyl acetate 7:1 as a mobile phase, yield
66%, m.p. 132ꢀ134°C, IR (KBr, cmꢀ1): 1699 (C O, amide) and
(C O, amide) and 1668 (C O, amide); MS (EI) m/z (%): 414 (10)
–
–
–
–
–
–
þ
1646 (C O, amide); MS (EI) m/z (%): 418 (14.57) (M þ1), 84
(Mþ), 81 (100); 1H NMR (CDCl3): 1.28–2.36 (m, 8H, cyclohexyl
protons), 2.84–2.95 (m, 2H, cyclohexyl protons), 4–4.02 (m, 1H,
–
–
1
(100); H NMR (CDCl3): 1.36–2.22 (m, 12H, cyclohexyl protons,
–
–
pyrrolidine protons), 2.54 (s, 4H, pyrrolidine protons), 2.93–3.28
CH –C O), 4.65–4.68 (m, 1H, CH –C O), 6.47 (s, 1H), 6.72 (s,
–
2 2
–
–
(m, 4H, cyclohexyl protons, CH –C O), 7.08–7.25(m, 11H, CH–N,
1H) (CH–N, imidazole proton), 7.02–7.36 (m, 12H, Har.,
–
2
ß 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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585

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Arch. Pharm. Chem. Life Sci. 2015, 348, 575–588
M. N. Aboul-Enein et al.
Archiv der Pharmazie
imidazole); 13C NMR (CDCl3): 22.07, 22.26, 24.3, 30.33, 31.48
(5CH2–cyclohexyl, 2CH2–pyrrolidine, CH3), 53.74 (2CH2–pyrrolidine),
–
–
(5CH –cyclohexyl), 49.68(CH –C O), 64.22, 75.66 (C–cyclohexyl,
60.9, 64.12, 75.63 (CH –C O, C–cyclohexyl, CH–N), 126.24,
–
–
2
2
2
CH–N), 120.17, 126.67, 127.39, 127.91, 129.16, 129.31, 129.65,
130.45, 134.2, 137.43, 137.93 (aromatic and imidazole carbons),
127.6, 128.88, 129.49, 129.7, 129.57, 132.09, 137.25, 138.45
–
–
–
(aromatic carbons), 168.84 (C O, amide), 171.74 (C O,
–
–
–
164.87 (C O, amide), 171.11 (C O, amide). Anal. calcd. for
C
amide). Anal. calcd. for C27H33N3O2: C, 75.14; H, 7.71; N,
9.74. Found: C, 75.16; H, 7.59; N, 9.57.
–
–
25H26N4O2: C, 72.44; H, 6.32; N, 13.52. Found: C, 72.11; H, 5.99;
N, 13.32.
3-(4-Methylphenyl)-2-phenyl-1-(piperidin-1-ylacetyl)-1,3-
diazaspiro[4.5]decan-4-one (8v)
Purified by column chromatography using a mixture of
1-[(Diethylamino)acetyl]-3-(4-methylphenyl)-2-phenyl-
1,3-diazaspiro[4.5]decan-4-one (8s)
Purified by column chromatography using a mixture of
petroleum ether (40–60)/ethyl acetate 6:4 as a mobile phase,
petroleum ether (40–60)/ethyl acetate 6:4 as a mobile phase,
yield 60%, m.p. 148ꢀ150°C, IR (KBr, cmꢀ1): 1702 (C O, amide)
–
–
yield 61%, m.p. 102ꢀ104°C, IR (KBr, cmꢀ1): 1689 (C O, amide);
and 1657 (C O, amide); MS (EI) m/z (%): 446 (7.7) (M þ1), 98
þ
–
–
–
–
MS (EI) m/z (%): 433 (2.42) (Mþþ1), 86 (100); 1H NMR (CDCl3):
0.89–0.92 (t, J ¼ 6.7 Hz, 6H, (CH2–CH3)2), 1.29–2.11 (m, 8H,
cyclohexyl protons), 2.28 (s, 3H, CH3), 2.48–2.52 (t, J ¼ 6.7 Hz, 4H
(100); 1H NMR (CDCl3): 1.27–1.47 (m, 3H), 1.61–1.79 (m, 8H),
2.12–2.15 (m, 1H), 2.23–2.25 (m, 4H) (cyclohexyl protons and
piperidine protons), 2.27 (s, 3H, CH3), 2.4 (br s, 2H), 2.54–2.57
(m, 1H), 2.81–2.87 (m, 1H) (cyclohexyl protons and piperidine
–
(CH –CH ) ), 2.73–3.04 (m, 4H, cyclohexyl protons, CH –C O),
–
2
3 2
2
6.87–7.24 (m, 10H, CH–N, Har.); 13C NMR (CDCl3): 11.49
(2CH2–CH3), 21.16, 22.17, 22.4, 24.47, 30.11, 31.69
protons), 2.95–2.97 (m, 1H), 3.04–3.3.06 (m, 1H) (CH –C O),
–
–
2
6.95–7.29 (m, 10H, CH–N, Har.); 13C NMR (CDCl3): 21.07, 22.07,
22.34, 23.82, 24.42, 25.92, 30, 31.58 (5CH2–cyclohexyl, 3CH2
piperidine), 54.04 (2CH2–piperidine), 60.4, 64.16, 75.39
–
(5CH –cyclohexyl, CH ), 46.67 (2CH –CH ), 59.09 (CH –C O),
–
2
3
2
3
2
64.15, 76.93 (C–cyclohexyl, CH–N), 126.52, 127.37, 128.87,
–
129.44, 129.78, 132.07, 138.4 (aromatic carbons), 169.64
(CH –C O, CH2–N, C–cyclohexyl), 126.14, 127.53, 128.77,
–
2
–
–
(C O, amide), 171.77 (C O, amide). Anal. calcd. for
129.36, 129.67, 132.07, 137.18, 138.32 (aromatic carbons),
–
–
–
–
C27H35N3O2: C, 74.79; H, 8.14; N, 9.69. Found: C, 74.99; H,
168.43 (C O, amide), 171.59 (C O, amide). Anal. calcd. for
–
–
8.35; N, 9.89.
C28H35N3O2: C, 75.47; H, 7.92; N, 9.43. Found: C, 75.16; H, 8.16;
N, 9.26.
1-[(Dipropylamino)acetyl]-3-(4-methylphenyl)-2-phenyl-
1,3-diazaspiro[4.5]decan-4-one (8t)
Purified by column chromatography using a mixture of
3-(4-Methylphenyl)-1-(morpholin-4-ylacetyl)-2-phenyl-
1,3-diazaspiro[4.5]decan-4-one (8w)
petroleum ether (40–60)/ethyl acetate 7:3 as a mobile phase,
Purified by column chromatography using a mixture of
yield 62%, m.p. 114ꢀ116°C, IR (KBr, cmꢀ1): 1692 (C O, amide)
petroleum ether (40–60)/ethyl acetate 6:4 as a mobile phase,
–
–
þ
and 1670 (C O, amide); MS (EI) m/z (%): 461 (0.04) (M ), 114
yield 63%, m.p. 154ꢀ156°C, IR (KBr, cmꢀ1): 1707 (C O, amide)
–
–
–
–
(100); 1H NMR (CDCl3): 0.81–0.84 (t, J¼ 7.6 Hz, 6H,
(CH2–CH2–CH3)2), 1.32–2.48 (m, 19H) (cyclohexyl protons,
(CH2–CH2–CH3)2, (CH2–CH2–CH3)2, CH3), 2.78–3.05 (m, 4H) (cyclo-
and 1644 (C O, amide); MS (EI) m/z (%): 448 (0.32) (M þ1),
þ
–
–
100 (100); 1H NMR (CDCl3): 1.37–1.78 (m, 6H, cyclohexyl
protons), 2.06–2.25 (m, 3H, cyclohexyl protons), 2.28 (s, 3H,
CH3), 2.43 (br s, 2H, morpholine protons), 2.45 (br s, 2H,
morpholine protons), 2.59–2.61 (m, 1H, cyclohexyl proton),
–
hexyl protons, CH –C O),6.9(s,1H, CH–N), 7.03–7.25 (m, 9H, Har.);
–
2
13C NMR (CDCl3): 11.94 (2CH2–CH2–CH3), 19.57, 21.14, 22.17,
22.37, 24.46, 30.17, 31.75 (2CH2–CH2–CH3, 5CH2–cyclohexyl, CH3),
–
2.87–3.07 (m, 2H, CH –C O), 3.74–3.8 (m, 4H, morpholine
–
2
55.66 (2CH2–CH2–CH3), 59.56, 64.18, 75.63 (CH –C O,
protons), 6.85 (s, 1H, CH–N), 6.93–7.31 (m, 9H, Har.);13C NMR
(CDCl3): 21.07, 22.04, 22.29, 24.38, 30.14, 31.49
(5CH2–cyclohexyl, CH3), 53.24 (2CH2–morpholine), 62.94,
–
–
2
C–cyclohexyl, CH–N), 126.53, 127.33, 128.91, 129.49, 129.79,
–
132.04, 137.47, 138.25 (aromatic carbons), 169.03 (C O, amide),
–
–
–
171.61(C O, amide). Anal. calcd. forC29H39N3O2: C, 75.45; H, 8.52;
64.24, 66.59, 75.76 (CH –C O, CH2-N, 2CH2–morpholine,
–
–
2
N, 9.10. Found: C, 75.11; H, 8.95; N, 8.89.
C–cyclohexyl), 126.3, 127.41, 128.98, 129.64, 129.74, 131.86,
–
137.45, 138.09 (aromatic carbons), 167.69 (C O, amide),
–
–
3-(4-Methylphenyl)-2-phenyl-1-(pyrrolidin-1-ylacetyl)-1,3-
diazaspiro[4.5]decan-4-one (8u)
171.66 (C O, amide). Anal. calcd. for C27H33N3O3: C, 72.46;
–
H, 7.43; N, 9.39. Found: C, 72.17; H, 7.09; N, 9.21.
Purified by column chromatography using a mixture of
methylene chloride/ethyl acetate 7:1 as a mobile phase, yield
1-(1H-Imidazol-1-ylacetyl)-3-(4-methylphenyl)-2-phenyl-
1,3-diazaspiro[4.5]decan-4-one (8x)
52%, m.p. 140ꢀ142°C, IR (KBr, cmꢀ1): 1703 (C O, amide) and
–
–
þ
–
–
1651 (C O, amide); MS (EI) m/z (%): 432 (3.82) (M þ1), 84
Purified by column chromatography using a mixture of
chloroform/ethyl acetate/methanol 7:5:3 as a mobile phase
followed by crystallization from a mixture of petroleum ether
(40–60)/ethyl acetate, yield 63%, m.p. 150ꢀ152°C, IR (KBr,
(100); 1H NMR (CDCl3): 1.34–1.36 (m, 1H, cyclohexyl proton),
1.64–1.76 (m, 8H, cyclohexyl protons, pyrrolidine protons),
2.07–2.24 (m, 6H, CH3, cyclohexyl protons), 2.45–2.54 (m, 5H,
cyclohexyl proton, pyrrolidine protons), 2.93–3.12 (m, 3H,
cmꢀ1): 1708 (C O, amide) and 1672 (C O, amide); MS (EI) m/z
–
–
–
–
cyclohexyl proton, CH –C O), 6.82–7.27 (m, 10H, CH–N, Har.);
(%): 428 (1.15) (Mþ), 81 (100); H NMR (CDCl3): 1.32–2.11 (m,
1
–
–
2
13C NMR (CDCl3): 21.14, 22.15, 22.42, 23.78, 24.49, 30.54, 31.61
8H, cyclohexyl protons), 2.26 (s, 3H, CH3), 2.72–2.92 (m, 2H,
ß 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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586

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Arch. Pharm. Chem. Life Sci. 2015, 348, 575–588
Anticonvulsant Activity of Diazaspirodecan-4-ones
Archiv der Pharmazie
–
cyclohexyl protons), 4.11–4.62 (m, 2H,CH –C O), 6.49 (s, 1H),
failure to observe even a threshold seizure (a single episode
of clonic spasms of a least 5 s duration) was defined as
protection [35].
–
2
6.69 (s, 1H) (CH–N, imidazole), 6.92–6.93 (d, J ¼ 8 Hz, 2H, Har.),
6.99 (s, 1H, imidazole), 7.05–7.06 (d, J ¼ 8 Hz, 2H, Har.), 7.23 (s,
1H, imidazole), 7.28–7.37 (m, 5H, Har.); 13C NMR (CDCl3): 21.04,
22, 22.2, 24.26, 30.33, 31.47 (5CH2–cyclohexyl, CH3), 49.67
(CH –C O), 64.44, 76.28 (C-cyclohexyl, CH–N), 120.2, 126.43,
127.37, 128.73, 129.51, 129.83, 130.26, 131.49, 137.59, 137.77,
137.83 (aromatic and imidazole carbons), 164.77 (C O,
amide), 171.06 (C O, amide). Anal. calcd. for C26H28N4O2: C,
72.87; H, 6.59; N, 13.07. Found: C, 72.67; H, 6.75; N, 12.89.
MES test:Animals were randomly assigned to groups of six
mice each. The first group served as the control group. The
second group received the reference drug diphenylhydantoin
at a dose of 45mg/kg ꢂ 0.16 mmol/kg and the other groups of
mice received individually the test compounds by intraperito-
neal injection with the dose that induces maximum protection
in the PTZ test. Thirty minutes later, electroconvulsions were
induced by a current (fixed current intensity of 25mA, 0.2 s
stimulusduration) deliveredviaearclip [36] bya Rodent Shoker
generator (current stimulator Type 221, Hugo Sachs Elektronik,
Freiburg, Germany). The typical maximal seizure lasts approxi-
mately 22 s. Failure to extend the hind limbs to an angle with
trunk greater than 90° is defined as protection [37].
Neurotoxicity screen: The neurotoxicity of the tested
compounds was evaluated by adopting the rotarod test [38],
which is designed to detect minimal neurological deficit. In
this test, the animals were trained to maintain equilibrium on
a rotating 1-inch diameter knurled plastic rod at a speed of
6 rpm for at least 1 min in each three trials using a rotarod
device (UGO Basile, 47600, Varese, Italy). Only animals which
fulfill this criterion were included in the experiment. The
selected trained mice were classified into control and
experimental groups (n ¼ 6). The animals in the experimental
groups were dosed (i.p.) with one of the test compounds at
doses which exerted the maximal protection in the PTZ test.
Thirty minutes later, the mice were placed again on the
rotating rod and the neurotoxicity was indicated by the
inability of the animal to maintain equilibrium on the rod for
at least one min.
–
–
2
–
–
–
–
Biological studies
Materials
Animals: Swiss male albino mice weighing 19–25 g were used
for evaluation of the anticonvulsant and neurotoxicity of the
target compounds 6a–d and 8a–x. Animals used in this study
were purchased from the Animal House Colony of the
National Research Centre, Cairo, Egypt. Animals were housed
under standardized conditions of room temperature, relative
humidity, light/dark cycle, and were allowed free access to
water and standard mice laboratory chow throughout the
whole experimental period. Procedures involving animals and
their care were performed after the Ethics Committee of
the National Research Centre and in accordance with the
recommendations for the proper care and use of laboratory
animals, “Canadian Council on Animal Care Guidelines,
1984”. Additionally, all efforts were made to minimize
animals suffering and to use only the number of animals
necessary to produce reliable data.
Drugs and chemicals: Phenobarbital (Memphis Co. Pharm
and Chem. Ind., Cairo, Egypt), ethosuximide (Pfizer Co., Giza,
Egypt), diphenylhydantoin (Nasr Co., Giza, Egypt), Tween 80,
and PTZ (Sigma, St. Loius, MO, USA) were used. Phenobarbital,
ethosuximide, and PTZ were dissolved in physiologic saline
solution. Diphenylhydantoin was dissolved in slightly alkalin-
ized saline with 0.1 mmol potassaium hydroxide. Reference
drugs and tested compounds were administered intraperito-
neally (i.p.) in volumes of 0.1 mL/10 g of mice body weight.
Determination of the ED50: Anticonvulsant potential of the
tested compounds was expressed in term of median effective
dose (ED50). Groups of mice were given range of doses of the
test compound until at least three points were established in
the range of 15–84% seizure protection. From the plot of
these data, the respective ED50 value and the confidence limits
were calculated [39].
Methods
Animals were allowed to acclimatize to laboratory conditions
for one week before starting the experiments. Mice were
randomly assigned to control, reference, and experimental
groups consisting of six mice each. Each mouse was used only
once. All the tested compounds were suspended in 7% Tween
80 as a vehicle.
The authors thank the National Research Centre, Dokki, Giza,
Egypt, for the support of this research through project No.
10010302 (2013–2016).
The authors have declared no conflict of interest.
scPTZ test: To determine the production of threshold or
minimal clonic seizures, 85 mg/ kg PTZ [32] was injected
subcutaneously in a loose fold of skin on the back of the mice
neck 30 min after individually i.p. injection of the reference
drugs ethosuximide (150 mg/kg ꢂ 1.06 mmol/kg) [20], pheno-
barbital (30 mg/kg ꢂ 0.13 mmol/kg) [33], or one of the test
compounds in the dose range of 4–37 mg/ kg. Meanwhile, the
control experiments were performed using the solvent alone.
Each animal was placed in a single cage to minimize the
stress [34] and observed for 30 min after PTZ administration,
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