Synthesis and anticonvulsant evaluation of (R)-and (S)-3-carbobenzyloxy- amino-1-oxysuccinimides

Article abstract of DOI:10.14233/ajchem.2013.14200

A series of (R)-and (S)-3-carbobenzyloxy-amino-1-oxysuccinimides (5a-d) [(S)-3-carbobenzyloxy-amino-1-benzoyloxysuccinimde, (R)-3-carbobenzyloxy-amino- 1-acetyloxysuccinimde, (R)-3-carbobenzyloxy-amino-1,4-nitrobenzoyloxysuccinimde, (R)-3-carbobenzyloxyamino-1,4-fluorobenzoyloxysuccinimde] were synthesized and investigated their anticonvulsant activities in maximal electric shock seizure test and pentylenetetrazole induced seizure test.

Full text of DOI:10.14233/ajchem.2013.14200

Asian Journal of Chemistry; Vol. 25, No. 11 (2013), 5948-5950
http://dx.doi.org/10.14233/ajchem.2013.14200
Synthesis and Anticonvulsant Evaluation of
(R)- and (S)-3-Carbobenzyloxy-amino-1-oxysuccinimides
DO-HUN LEE
Department of Chemistry, Dong-A University, Busan 604-714, Republic of Korea
Corresponding author: Fax: +82 51 2001053; E-mail: dohlee@dau.ac.kr
(Received: 18 June 2012; Accepted: 22 April 2013)
AJC-13374
A series of (R)-and (S)-3-carbobenzyloxy-amino-1-oxysuccinimides (5a-d) [(S)-3-carbobenzyloxy-amino-1-benzoyloxysuccinimde, (R)-
3-carbobenzyloxy-amino-1-acetyloxysuccinimde, (R)-3-carbobenzyloxy-amino-1,4-nitrobenzoyloxysuccinimde, (R)-3-carbobenzyloxy-
amino-1,4-fluorobenzoyloxysuccinimde] were synthesized and investigated their anticonvulsant activities in maximal electric shock seizure
test and pentylenetetrazole induced seizure test.
Key Words: Amino-1-oxysuccinimides, Maximal electric shock seizure test, Pentylenetetrazole induced seizure test, Anticonvulsant
activity.
anticonvulsant compounds, known to act by different pharma-
cological mechanisms each other. From the studies of structural
similarities of anticonvulsants, we find out the interesting facts
that anticonvulsant compounds included the common structural
moieties such as NH-CO-C-N and imide in their structures
and also some MNDA antagonist, showing anticonvulsive effect,
had structural similarity to aspartic acid, known as excitatory
amino acid, in view of bioisoster. So we thought that the new
anticonvulsants could be possibly developed from the aspartic
acid in view of their structures. We designed the following
imides such as A, having aforesaid common structures such
as NH-CO-C-N, imide and aminocarbonyl of GABA in their
structure originated from aspartic acid as shown in Fig. 1.
INTRODUCTION
Epilepsy is a common and diverse set of chronic neuro-
logical disorders characterized by seizures recent estimate
indicate that 1 % of population is affected some forms of
epilepsy and that 20-40 % of epileptic patients failed to expe-
rience significant seizure control with the drugs currently avail-
able1-5. Futheremore, the antiepileptic drug presently used in
clinical practics suffer from a broad range of adverse side effects
including sedation, tetratogenecity, cognitive dulling and liver
toxicity6-9. The clinically epilepsy consists of various forms of
seizure, so that there is a need for combination and repeat
therapy to control the such complex convulsion. Owing to this
multitherapy, there is a danger of toxic and troublesome side
effect. Consequently, there is a need for the development of
new antiepileptic compound having broader clinical spectrum
and lower toxic side effects. Recently, there has been many
trials for the development of new typed anticonvulsant comp-
ounds including derivatives of various amino acid such as
alanine derivatives and N-benzoyl and N-phenyl glycine amide
and structural modification of currently used drug such as
hydantoin, succinimdes and glutarimides and various GABA
O
N R
A
HN
O
O
OCH Ph
2
Fig. 1
related compounds10-14
.
But these compounds had some limitation in clinical use
that some drug showed anticonvulsant effect only in maximal
electric shock seizure test (MES) or pentylenetetrazole induced
seizure test (PTZ). So we were interested in the development
of new anticonvulsant compounds of broad spectrum. In connec-
tion with the studies for the development of anticonvulsants,
we tried examining the structural similarities of currently available
Usually the stereoisomers exhibited different pharmaco-
logical activities, so we tried preparing all the (R)- and (S)-
compounds in order to investigate the pharmacological diffe-
rences between their stereoisomers. The compounds (1a-d)
could be prepared from the corresponding (R)-or (S)-aspartic
acid in moderate yields by known chemical reactions as shown
in Scheme-I.

Vol. 25, No. 11 (2013)
Synthesis and Anticonvulsant Evaluation of (R)- and (S)-3-Carbobenzyloxy-amino-1-oxysuccinimides 5949
O
aspartic anhydride 3 (2.49 g, 10 mmol) and hydroxylamine
CO H
2
CO H
2
hydrochloride (0.83 g, 12 mmol) in H2O (2 mL) with Na2CO3
(0.64 g) was stirred at 0 ºC for 1 h. The reaction solution was
concentrated in vaccuo. The white crystal (1.45 g, 55 %) was
recrystallized by solution of ethanol and H2O.Yield 55 % m.p.
ºC; Rf 0.5 (TLC eluent; benzene: THF:formic acid = 15:5:1,
v/v/v); IR (KBr, νmax, cm-1): 3500, 3370, 3110, 1710, 1500,
1220; 1H NMR ( DMSO) δ 2.50 (2H, m), 2.99 (1H, m), 4.42
(1H, s), 5.05 (2H, s), 7.67 (5H, s), 1082 (1H, s).
O
i)
ii)
iii)
HN
C
CO H
2
HN
O
H N
2
CO H
2
O
O
O
CH
OCH
3
3
2
3
1
5a: (R)- and (S)-
5a :(R)- and (S)-
O
O
N
O
O
O
R
C
OH
N OR
iv)
5b: (R)- and (S)-
5b :(R)-and(S)-
O
(S)-3-Carbobenzyloxy-amino-1-hydroxy succinimde
1
(4): yield 54 % The IR and H NMR spectra of (S)-4 were
identical with the IR and 1H NMR spectra of (R)-4.
HN
O
HN
R
C CH
3
O
OCH
OCH
3
3
5c: (R)- and (S)-
5c :(R)- and (S)-
O
Typical experimental procedure for synthesis of (R)-3-
carbobenzyloxy-amino-1-benzoyloxysuccinimde: A mixture
of synthesized (R)-carbobenzyloxy-amino-1-hydroxysuccinimde
(4) (0.56 g, 2 mmol) benzoylchloride (0.34 g, 2 mmol) and
Na2CO3 (0.25 g) with acetone 8 mL H2O 5 mL were stirred at
room temperature for 5 h. After EtOAc (200 mL) was added,
the reaction mixture was added saturated NaHCO3 solution
(50 mL), 5 % HCl (50 mL) and H2O (50 mL) then the confined
organic layers were concentrated in vaccuo. The obtained (R)-
3-carbobenzyloxy-amino-1- benzoyloxysuccinimide (5a)
(0.35 g, 46 %) was recrystallized with EtOAc and n-hexane.
m.p. 141-142 ºC; Rf 0.7 (TLC eluent; EtOAc: n-hexane = 1:1,
%); IR (KBr, νmax, cm-1): 3410, 3100, 1950, 1730, 1690, 1510;
1H NMR (DMSO) δ 2.85 (2H, m), 4.77 (1H, s), 5.07 (2H, s),
7.77 (10H, m). (S)-3-Carbobenzyloxy-amino-1-benzoyloxy-
4
5
R
C
NO
2
5d: (R)- and (S)-
5d :(R)-and(S)-
O
i) ClCOOCH2Ph, NaOH
i) ClCOOCH Ph, NaOH
iii) NH2OHHC2l, Na2CO3
ii) O(COCH3)2
ii) O(COCH
iv) RCl, Na2CO3
3)2
R
C
F
iii) NH2OHHCl, Na2CO3
iv) RCl, Na CO3
2
Scheme-I
EXPERIMENTAL
Melting points were determined on a Büchi 510 capillary
melting point apparatus and uncorrected. Infrared spectra were
recorded on a Perkin-Elmer 683 spectrophotometer. NMR
spectra were recorded on a Varian XL-300 or Bruker AC 200
FT-NMR spectrometer in CDCl3 containing Me4Si as an
internal reference. Mass spectra were obtained by using JEOL
JMS DX 303 or HP 5892 mass spectrometer.
(R)-3-Carbobenzyloxy-amino-aspartic acid (2): To a
solution of (R)-aspartic acid 1 (5.20 g, 40 mmol) and NaOH
(3.52 g, 88 mmol) in H2O (35 mL) and acetone (35 mL) at 0
ºC was added solution of carbobenzyloxy chloride (6.82 g, 40
mmol) and NaOH (1.76 g, 44 mmol) in H2O (17 mL) and
acetone (17 mL). The reaction mixture was stirred at room
temperature for 7 h. After reaction solution was concentrated
in vaccuo, it was carefully acidified (pH = 2) with conc HCl.
Then the white solid was obtained in good yield (8.20 g, 77
%). m.p. 115-116 ºC; Rf 0.6 (TLC eluent; benzene:THF:formic
acid = 15:5:1, v/v/v); IR (neat, νmax, cm-1): 3500, 3350, 3100,
1
succinimde (5a): yield 0.37 g (49 %). The IR and H NMR
spectra of (S)-5a were identical with the IR and 1H NMR spectra
of (R)-5a.
(R)-3-Carbobenzyloxy-amino-1-acetyloxysuccinimde
(5b): yield 56 % m.p. 103-104 ºC; Rf 0.6 (TLC eluent; EtOAc:n-
hexane = 1:1, %) ; IR (KBr, νmax, cm-1): 3380, 3370, 3100,
3000, 1720, 1700, 1510, 1210; 1H NMR (DMSO) δ 2.33 (3H,
s), 2.72 (2H, m), 4.64 (1H, s), 5.02 (2H, s), 7.71 (5H, m).
(R)-3-Carbobenzyloxy-amino-1-4-nitrobenzoyloxy-
succinimde (5c): yield 48 %; m.p. 175-176 ºC; Rf 0.5 (TLC
eluent; EtOAc:n-hexane = 2:1, v/v); IR (KBr, νmax, cm-1): 3400,
3100, 3100, 3000, 1850, 1700, 1320, 1280; 1H NMR ( DMSO)
δ 2.86 (2H, m), 2.72 (2H, m), 4.77 (1H, s), 5.08 (2H, s), 8.15
(10H, m).
1
1700, 1680; H NMR (200 MHz, DMSO) δ 2.70 (2H, m),
4.30 (1H, m) , 5.16 (2H , S), 7.55 (5H, m), 12.64 (1H , br) (S)-
3-carbobenzyloxy-amino-aspartic acid 2: yield 77 %; m.p. 115-
116 ºC; Rf 0.6 (TLC eluent; benzene; THF; formic acid =
15:5:1, v/v/v); the IR and 1H NMR spectra of (R)-2 was iden-
tical with the IR and 1H NMR spectra of (R)-2.
(R)-3-Carbobenzyloxy-amino-1-4-fluorobenzoyloxy-
succinimde (5d): yield 74 %; m.p. 176-177 ºC; Rf 0.4 (TLC
eluent; EtOAc:n-hexane = 2:1, v/v); IR (KBr, νmax, cm-1): 3400,
(R)-3-Carbobenzyloxy-amino-aspartic anhydride (3):
A mixture of synthesized (R)-2 10 g, 37 mmol) and acetic
anhydride (100 mL) was stirred at room temperature for 2 h.
The reaction mixture was concentrated in vaccuo.After concen-
trating it was added diethyl ether 100 mL. Then the white solid
was obtained in good yield (8.4 g, 91 %) m.p. 134-135 ºC; Rf
0.5 (TLC eluent; benzene:THF:formic acid = 15:5:1, v/v/v);
IR (neat, νmax, cm-1): 3370, 3350, 3110, 1710, 1500, 1220; 1H
NMR (200 MHz, DMSO) δ 2.50 (2H, m), 2.99 (1H, m), 4.42
(1H, S), 5.05 (2H, S), 7.57 (5H, m), 10.82 (1H , S).
1
3100, 3100, 3000, 1730, 1690, 1550, 1290, 1190; H NMR
(DMSO) δ 2.87 (2H, m), 4.77 (1H, s), 5.08 (2H, s), 7.80 (10H,
m). The IR and 1H NMR spectra of (S)-5b (60 %), 5c (49 %),
5d (67 %) were identical with the IR and 1H NMR spectra of
(R)-5b, 5c and 5d.
RESULTS AND DISCUSSION
All products gave satisfactory spectral data. So the comp-
ounds 5a-d were submitted to the following anticonvulsant
tests. It was reported that MES test was correlated to generalized
tonic clonic seizure and PTZ test to generalized absence seizure.
So these two kinds of seizure test are very meaningful for the
clinical prediction of anticonvulsant drug candidates. There-
fore we investigated the anticonvulsant activity for those
compounds((R)-5a-d and (S)-5a-d) in maximal electric shock
(S)-3-Carbobenzyloxy-amino-aspartic anhydride (3):
m.p. 95-96 ºC; Rf 0.8 (TLC eluent; ethylacetate); the IR and
1
1H NMR spectra of (S)-3 was identical with the IR and H
NMR spectra of (R)-3.
(R)-3-Carbobenzyloxy-amino-1-hydroxysuccinimde
(4): A mixture of synthesized (R)-3-carbobenzyloxy-amino-

5950 Lee
Asian J. Chem.
3. D. Lindhart and R.J.E.A. Hopperner, Epilepsia, 25, 77 (1984).
4. J.A. Vida, In ed.: W.O. Foye, Principle of Medicinal Chemistry, Lea &
Febiger: Philadelphia, Ch. 11 (1995).
seizure test (MES test) and pentylenetetrazole induced seizure
test (PTZ test). The results of anticonvulsant activity are
summarized in Table-1.
5. (a) H. Kohn, K.N. Sawhney, D. LeGall and J.D. Leader, J. Med. Chem.,
34, 2444 (1991); (b) H. Kohn, K.N. Sawhney, D. LeGall and J.D. Cinley,
J. Med. Chem., 33, 919 (1990); (c) J.D. Conley and H. Kohn, J. Med. Chem.,
30, 567 (1987).
TABLE-1
SELECTED ANTICONVULSANT EVALUATION OF
(R)-, (S)-CARBOBENZYLOXY-AMINO-1-3-
HYDROXYLSUCCINIMDES IN MICE
6. (a) J. Takahashi, K. Ogui, H. Fujimura, I. Satoda, T. Fukui and Y.
Yamamoto, Swiss Patent 393355, Oct. 30 (1965); (b) D.E. Thorne, US
Patent. 3657341, April 8 (1972).
a
ED50 (mg/Kg)
Compound
Config
7. (a) W.J. Brouillette, V.P. Jestkov, M.L. Brown, M.S. Akhatar, T.M.
DeLorey and G.B. Brown, J. Med. Chem., 37, 3289 (1994); (b) C.H.
Kwon, M.T. Iqbal and J.N.D. Eurpel, J. Med. Chem., 34, 1845 (1991).
8. (a) V.A. Farrar, M. Ciechanowicz-Rutkowska, J. Grochowski, P. Serda,
G. Filippini, C.N. Hinko, A. El-Assadi, J.A. Moore, I.O. Edafiogho,
C.W. Andrew, M. Cory, J.M. Nicholson and K.R. Scott, J. Med. Chem.,
36, 3517 (1993); (b) I.O. Edafiogho, K.R. Scitt, J.A. Moore, V.A. Farrar
and J.M. Nicholson, J. Med. Chem., 34, 387 (1991); (c) M.R. Borenstein
and P.H. Duukas, J. Pharm. Sci., 76, 300 (1987); (d) M.J. Kornet,
J. Pharm. Sci., 73, 405 (1984).
MES (P1)b
PTZc
103.2
137.5
81.3
5a
R
R
R
R
S
S
S
S
–
97.2
5b
172.5
98.3
5c
5d
125.2
121.3
92.3
100.0
106.3
89.7
5a
5b
90.6
112.3
97.2
5c
5d
102.2
21.8(3.1)
9. (a) D.T. Witiak, S.K. Seth, E.R. Baizmann, S.L. Weibel and H.H. Wolf,
J. Med. Chem., 19, 1419 (1976); (b) H.Y.Aboul-Eneine, C.W. Schauberger,
A.R. Hansen and L.J. Fischer, J. Med. Chem., 18, 736 (1975).
10. (a) K.E. Andersen, C. Braestrup, F.C. Gronwald, A.S. Jorgensen, E.B.
Nielsen, U. Sonnewald, P.O. Sorensen, P.D. Suzdak and L.J.S. Knutsen,
J. Med. Chem., 36, 1716 (1993); (b)V. N'Goka, G. Schlewer, J.M. Linget,
J.P. Chambon and C.G. Wermuth, J. Med. Chem., 34, 2547 (1991); (c)
J.R. Bruke and R.B. Silvermann, J. Am. Chem. Soc., 113, 9329 (1991).
11. (a) P.C.K. Pook, D.E. Jane and J.C. Watkins, J. Med. Chem., 37, 4288
(1994); (b) R. Heckendorn, H. Allgeier, J. Baud, W. Grunzenhauser and
C. Angst, J. Med. Chem., 36, 3721 (1993).
Phenobarbitald
13.1(5.3)
aAll compounds were administered ip to ICR male mice and all
anticonvulsant tests were performed in groups of 4 mice 30 min after
test compound administration. bMaximal electric shock seizure test ;
50 mA, 60 Hz, ac, 02 s. cSubcutaneous pentylenetetrazoyl (90 mg/Kg)
induced seizure test. dRef 14.
It is found that the (R)-isomer was more active than (S)-
isomer about the anticonvulsant activity. Especially, (R)- and
(S)-5a-d were reported to be active in only PTZ. We continue
to synthesize their analogs and evaluate their anticonvulsant
activities in order to develop more active anticonvulsant
compounds and define the structure-activity relationship more
distinctly.
12. For the preparation of compound 4: M. Itoh, Chem. Pharm. Bull., 17,
1679 (1969); For the preparation of compounds 1 and 2: S.R. Sandler
and W. Karo, Organic Functional Group Preparation; Academic Press:
New York, Vol. 3, p. 253 (1972).
13. (a) E.A. Swinyard, J.H. Woodhead, H.S. White and M.R. Franklin, in
ed: R. Levy, General Priciples, Experimental Section, Quantification
and Evaluation of Anticonvulsants in Antiepileptic Drugs, Ravan Press,
New York, edn. 3, p. 88 (1988); (b) R.L. Krall, J.K. Penry, B.G. White,
H.J. Kupferberg and C.A. Swinyard, Epilepsia, 19, 409 (1978).
14. R.J. Porter, J.J. Cereghino, G.D. Gladding, B.J. Hessie, H.J. Kupferberg,
B. Scoville and B.G. White, Cleveland Clin. Q., 51, 283 (1984).
REFERENCES
1. (a) J.M. Liebmann and A. Schneider, Ann. Med. Chem., 20, 11 (1985);
(b) E.A. Swinyard, Antiepilepic Drug, Ravan Press: New York, edn. 2,
p. 5 (1982).
2. D. Schmidt, Epilepsia, 25, 244 (1984).