Curare-like camphor derivatives and their biological activity

Article abstract of DOI:10.1134/S1068162015020156

The synthesis of symmetric dimeric camphor derivatives containing two quaternary nitrogen atoms was performed and their myorelaxant activity in mice was evaluated. For the comparison, some salts derived from meta-and para-xylylene dibromides were synthesi

Full text of DOI:10.1134/S1068162015020156

ISSN 1068ꢀ1620, Russian Journal of Bioorganic Chemistry, 2015, Vol. 41, No. 2, pp. 178–185. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © A.S. Sokolova, E.A. Morozova, V.G. Vasilev, O.I. Yarovaya, T.G. Tolstikova, N.F. Salakhutdinov, 2015, published in Bioorganicheskaya Khimiya, 2015,
Vol. 41, No. 2, pp. 203–211.
CurareꢀLike Camphor Derivatives and Their Biological Activity
A. S. Sokolovaa, b, E. A. Morozovaa, V. G. Vasileva,
O. I. Yarovayaa, b, 1, T. G. Tolstikovaa, b, and N. F. Salakhutdinova, b
a Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences,
pr. Lavrentjeva 9, Novosibirsk, 630090 Russia
b Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090 Russia
Received June 25, 2014; in final form, August 27, 2014
Abstract—The synthesis of symmetric dimeric camphor derivatives containing two quaternary nitrogen
atoms was performed and their myorelaxant activity in mice was evaluated. For the comparison, some salts
derived from metaꢀ and paraꢀxylylene dibromides were synthesized and their activity was tested.
Keywords: camphor, muscle relaxant activity, rotaꢀrod test, inclined plane test
DOI: 10.1134/S1068162015020156
1
INTRODUCTION
relaxation have been approved for application in anaꢀ
esthesiology [7] (formula). Atracurium (II), which is
structurally similar with tubocurarin, is a synthetic
compound used in medical practice. Dithylin (succiꢀ
nylcholine) (III) is a major representative of depolarꢀ
izing neuromuscular relaxants, which blocks neuroꢀ
muscular activation and causes relaxation of skeletal
muscles. This drug demonstrates a rapid and short
term effect and in spite of a number of side reactions
[8] is widely used in medicine. Neuromuscular relaxꢀ
ants with a steroidal backbone, being nondepolarizing
blocking agents with the myorelaxant activity close to
that of tubocurarin, do not display the hormonal activꢀ
One of the most effective current approaches to the
synthesis of biologically active compounds is functionꢀ
alization of the known biologically active molecules
with various pharmacophoric groups. Natural
resources serve as the major source of primary biomolꢀ
ecules. Now researchers specializing in the field of
medicinal chemistry pay special attention to the synꢀ
thesis and studies of symmetrical molecules bearing
two or more natural fragments in the backbone. Strucꢀ
tures of these natural fragments are very different.
They can be of the alkaloid [1, 2], steroid [3], monoꢀ
or diterpene [4, 5], etc. nature. Symmetrical nitrogenꢀ
containing compounds with natural fragments joined
with linkers and bearing in the backbone two quaterꢀ
nary nitrogen atoms display a wide spectrum of biologꢀ
ical activity. However, these compounds are most
known for their neuroblocking properties and are also
called curareꢀlike compounds.
ity. For example, arduan (IV) and pancuronium (V)
are approved for medical use [9] (formula). Until now,
steroidal myorelaxant drugs have displaced dithylin in
many hospitals due to a higher safety when used for the
relaxation of skeletal muscles.
However, none of the presently available muscle
relaxants meets the criteria for an ideal neuromuscular
blocking agent [10]. These criteria defined in the 1970s
include the rapid onset and the predetermined duraꢀ
tion of action, antidepolarizing mechanism of action,
rapid development of the effect, the lack of the cumuꢀ
lative action, the lack of cardiovascular side effects,
rapid and complete reversal with anticholinesterases,
and fast elimination from the body without regard to
renal/liver function or biotransformation into inactive
metabolites [11].
The biological activity of curare, concentrated
extracts of South American plants of the Strychnos and
Chondodendron species, has been studied for several
centuries. Curare and curareꢀlike compounds are used
in medicine as skeletal muscle relaxants, first of all, in
surgery. Compounds of different chemical classes
belong to such drugs, particularly, alkaloids containing
one or several tertiary amino groups, monoꢀ and di
quaternary nitrogen fragments within various backꢀ
bones, as well as the structures with positively charged
heteroatoms other than nitrogen [6].
In the 1970s, D.A. Kharkevich et al. systemically
searched for the most active derivatives of truxillic acid
[12]. Anatruxonium [13] and cyclobutonium [14], the
most effective compounds of this series, were impleꢀ
mented in medical practice in the USSR. Currently,
almost no studies on the search of new synthetic myoꢀ
relaxants are in progress. An exception is the studies of
Since 1953, when the structure of the active comꢀ
pounds of the pipe curare, alkaloid dꢀtubocurarin (I),
was found, many of its analogues causing muscular
1
Corresponding author: phone: +7 (383) 330ꢀ8870; eꢀmail:
ooo@nioch.nsc.ru.
178

CURAREꢀLIKE CAMPHOR DERIVATIVES
179
Kazan researchers on the potential myorelaxant propꢀ
RESULTS AND DISCUSSION
erties of some uracil derivatives [15]. Experiments with
animals are complicated by a significant drawback of
neuroblocking agents: an extremely small difference
exists between the doses used for treatment and those
paralyzing respiratory muscles and causing apnoea.
The goal of this work was the synthesis of symmetꢀ
rical curareꢀlike compounds containing in the backꢀ
bone two fragments of natural camphor molecule and
two quaternary nitrogen atoms joined with linkers of
different length and rigidity. We studied myorelaxant
activities of the compounds synthesized, compared
the activities with those of some structurally similar
compounds, and evaluated the structure–activity relaꢀ
tionship within the series synthesized.
As a basis for the synthesis of symmetrical derivaꢀ
tives we took a common natural molecule of the
monoterpene series, (+)ꢀcamphor (VI). Previously, it
was shown that symmetrical camphor imino derivaꢀ
tives displayed a marked antiviral activity [16]; amiꢀ
doalcohols based on the camphor backbone were
demonstrated to be highly effective antituberculosis
agents [17]. A characteristic feature of the camphor
structure is a rigid carbon backbone to some extent
similar to the adamantane backbone. It is known that
adamantane derivatives with quaternary ammonium
atoms joined with aliphatic chains manifest myorelaxꢀ
ant properties [6].
2Cl–
OCH3
HO
H
N+
2I–
O
O
+
+
N
N
O
O
HO
O
N+
O
H3CO
(I
)
(III)
O−
O S O
OCH3
OCH3
H3CO
N+
N
O
5
+
O
2
H3CO
H3CO
+
O
O
OCH3
OCH3
H3CO
(II)
2Br–
2Br–
OAc
OAc
N+
N+
N+
N
N+
N
AcO
AcO
H
H
(
IV
)
(V)
Formulas. Chemical structures of myorelaxant agents used in medical practice.
For the synthesis of the target compounds we synꢀ with azeotropic distillation of water in toluene in the
thesized nitrogenꢀcontaining camphor derivatives presence of BF3 Et2O (Scheme 1). For the preparaꢀ
bearing imine and tertiary amine groups in the backꢀ tion of symmetrical dimeric molecules, aliphatic dihꢀ
bone (VII XIII) using the interaction of halogenides alogenides with the varied length of the chain were
with tertiary amines (Scheme 1). Previously, we used as linkers (R, Scheme 1). For the evaluation of
described the synthesis of compounds (VIII XIII the impact of the linker rigidity and electron structure
·
–
–
)
and demonstrated their effective inhibitory properties we synthesized compound (XI) bearing an aromatic
against the influenza virus. Iminoamine (VII) used as ring (Scheme 1). The reaction of methyl iodide or
a starting compound in the synthesis of the derivatives ethyl bromide and the starting iminoamine (VII
was obtained in a yield of 85–90% by the reaction of resulted in the corresponding quaternary ammonium
camphor (VI) with ꢀdiethylethanꢀ1,2ꢀdiamine bases (XII) and (XIII) (Scheme 1).
)
N,N
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180
SOKOLOVA et al.
2Br–
ii
N+
N+
R
N
N
N
H2N
N
i
N
iii
O
Hal–
(VI
)
(
VII)
+
N R1
N
Scheme 1. The synthesis of compounds (VII)–(XIII).
Et O (1–5 mol %); ii) BrꢀCH ꢀRꢀCH ꢀBr (0.5 mol), CH CN; iii) R Hal, CH CN.
1
i) PhMe, BF
⋅
3
2
2
2
3
3
1
–R– (VIII) –(CH ) –; (IX) –(CH ) –; (X) –(CH ) –; (XI) pꢀPh–R ; (XII) –CH , Hal = I; (XIII) –C H , Hal = Br.
2 6 3 2 5
2 3
2 4
The study of the neuroblocking activity of comꢀ to 20 mg/kg (table). Among compounds (VIII)–(X),
pounds (VIII)–(XIII) bearing a camphor backbone no agent was found which could induce noticeable
and quaternary nitrogen atoms showed that only comꢀ neuroblockage in animals. It is noteworthy that the
pound (XI) containing a paraꢀsubstituted aromatic elongation of the linker chain in this series did not
ring in the linker chain could cause muscle relaxation affect the capacity of the compounds to induce muscle
in mice at doses of 10 mg/kg and 15 mg/kg (table). In relaxation but affected the compound toxicity: comꢀ
the rotaꢀrod test the capacity of the animals to remain pound (
X) with the longest aliphatic chain was the
on the rod after the injection of compound (XI most toxic (LD50 4.1 mg/kg), whereas LD50 values for
)
reduced and the time of the first fall from the rod the other members of this group were within the range
essentially decreased. The control animals did not fall of 9.2 to 12.5 mg/kg.
during the whole experimental time, whereas the aniꢀ
mals with dithylin fell immediately after they were
placed on the rod. Some animals (14 to 33%, depending
With the goal of studying the effects of shielding
the charged nitrogen atom in camphor imino derivaꢀ
tives on the biological activity of the compounds
tested, we synthesized another starting compound,
iminoamine (XIV), by the interaction of camphor
on the dose) that were administered compound (XI
)
could not keep the position on the inclined plane,
which served another evidence of the neuroblocking
activity of the compound under study. In this test the
control animals went up the inclined plane, whereas
the animals with the induced muscle relaxation went
down the plane and fell down as it was observed for the
dithylin group (table).
with
N,Nꢀdimethylꢀ1,2ꢀdiamine. Compound (XV)
was obtained under similar conditions, by the interacꢀ
tion of iminoamine (XIV) with paraꢀxylylene dibroꢀ
mide. For the studies of the positional relationship of
the linker aromatic ring substituents and the distance
between the quaternary nitrogen atoms of the
The monoquaternized salts of camphor iminoamꢀ “dimeric” molecule, we prepared compound (XIV
)
ine (XII) and (XIII) containing a charged nitrogen using a similar reaction of metaꢀxylylene dibromide
atom were inactive in any of the tests at the doses of 10 with compound (XVI) (Scheme 2).
2'
2Br–
17 17'
2
9
N+
N+
1
N
1'
N
14
N
N
ii
H2N
2
12'
12
18
18'
i
11
(XV)
N
5
O
1
N
iii
13
18
10
17
16
17'
16'
(VI)
2Br–
(
XIV)
N+
N+
19
N
1'
1
(
XVI)
Scheme 2. The synthesis of compounds (XIV)–(XVI).
Et O (1–5 mol %); ii ꢀBrCH –Ph–CH Br (0.5 mol), CH CN;
i) PhMe, BF
⋅
) p
3
2
2
2
3
iii) mꢀBrCH –Ph–CH Br (0.5 mol), CH CN.
2 2 3
RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY Vol. 41
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CURAREꢀLIKE CAMPHOR DERIVATIVES
181
Biological activity of compounds (VIII–XIII) in mice
Latency of the fall from the rod, s (120 s max)
Neuromuscular block
on an inclined plane, LD50, mg/kg
% of animals
Compound Dose, mg/kg
Control
attempt 1
attempt 2
attempt 3
120
120
120
120
120
120
0
(
(
(
(
VIII
)
5
10
10
15
5
0
33.3
0
9.2
10.3
4.1
115
5
110 10
120
120
IX)
120
120
109
8
87 16
120
98 13
120
25
0
X)
120
7
114
6
91 19
120
93 14
120
25
0
XI
)
5
120
12.3
10
15
10
117
103
2
8
65 15*
63 21*
120
106
6
14.3
33.3
0
90 30
120
(XII
)
120
not deterꢀ
mined
20
5
120
120
120
120
120
120
0
0
(
XIII
)
not deterꢀ
mined
10
20
5
120
120
120
120
120
120
120
0
0
115
5
(XV
)
120
0
14.9
10
15
10
10
15
20
5
109
104
120
8
53 13**
43 14***
60 35
75 14*
56 15**
25 6**
120
108
5
16.7
33.3
0
9
48 16**
(
XVI
)
115
110
5
5
12.5
27.2
(XVII
)
120
98 9*
120
0
49 9***
68 13***
120
0
0
(XVIII
)
120
0
13.9
22.7
10
10
15
20
10
15
5
85 9**
32 5***
30 30**
20 20***
–
84 11*
68 21*
100 20
–
20
0
(XIX
)
118
3
100 14
0
90 30
0
(XX
)
95 15
98 13
60 19*
–
118
3
0
20.6
94 13
90 19
–
0
(XXI
)
10
0
4.3
(
XXII
)
10
15
20
120
83 13**
35 16***
40 20*
0***
108 6*
105 6*
55 5*
0
30.4
120
110 10
0
0
Dithylin
2.5
0***
107
8
100
1.8
*
р
< 0.05; **
р
< 0.01; ***
р
< 0.001 compared to control.
RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY Vol. 41
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182
SOKOLOVA et al.
The activity studies of salts (XV) and (XVI) demonꢀ activity, whereas a decrease in the distance between
strated that compound (XV) displayed myorelaxant
properties similar to those of compound (XI): at a dose
of 10 mg/kg the latency to fall off the rod was reduced
and 16% of the animals could not keep themselves on
the inclined plane. Salt (XVI) did not show the neuꢀ
roblocking activity: the reduction of the time to fall
from the rod was not reliable and no positive results
were observed in the inclined plane test. The toxicity
of these salts did not differ from the toxicity of comꢀ
pound (XI). Thus, we could assume that shielding of
the charged nitrogen atom (the replacement of ethyl
by methyl radicals) in the “dimeric” molecules under
quaternary nitrogen atoms resulted in a reduced
capacity to relax muscles in animals.
For the evaluation of the role of the terpene backbone
in the salts tested for biological activity we synthesized a
series of bisꢀquaternized compounds (XVII)–(XXII
derived from the corresponding paraꢀ and meta
xylylene dibromides (Scheme 3). Salts (XVII),
XVIII), (XX), and (XXI) were obtained by a direct
)
ꢀ
(
interaction of the aromatic dibromo derivative with
the corresponding tertiary amine, and salts (XIX) and
(XXII), via the formation of tertiary amines followed
study did not have any influence on the neuroblocking by quaternization with methyl iodide.
7
2Br–
6
6'
2Br–
6
6'
4'
N+
2
4
5
5'
4
4'
7'
8
i
N+
N+
N+
5
i
Br
Br
7'
1
4
7
1
(
XX)
3
ii
2Br–
(
XVII)
9
ii
9'
Br
N
Br
2Br–
iii
1
7
N+
iii
N+
N+
8
8'
N+
5
2
3
6
(
XXI)
N
(
XVIII)
2I–
iv
2I–
N
N
iv
N+
N+
N+
N+
(XIX)
(
XXII
)
Scheme 3. The synthesis of compounds (XVII)–(XXII).
iii) NHMe , CH CN; iv) CH I, CH CN.
i) NMe , CH CN; ii) NEt , CH CN;
3
3
3
3
2
3
3
3
The study of the myorelaxant activity of these comꢀ bromides and iodides (XVII)–(XIX) and (XX)–
pounds showed that nearly all of them at doses of 10 to XXII), which implied the lack of the counterion
20 mg/kg following intraꢀabdominal administration effect on the activity of the compounds tested (table).
(
considerably reduced the time taken for the animal to
remain on the rod. However, only compound (XVIII
To summarize, we systematically studied a new
class of curareꢀlike compounds, diquaternized derivaꢀ
tives of natural bicyclic diterpenoid camphor. On the
basis of the research some conclusions can be made.
An increase in the length of the aliphatic chain among
)
affected the capacity to remain on the inclined plane
(table). Hence, in this case we can observe the violaꢀ
tion of coordination of movements in animals caused
by neurotoxic effects rather than by the myorelaxant
activity of the compounds tested. The fact that nearly
all of the compounds of this group (except (XVIII))
caused tremor, and even convulsions in some cases,
after physical exercises (the attempts of the animals to
remain on the rod) is in favor of this hypothesis.
(
VIII)–(X) led to an increase in the toxicity; shielding
of the charged atom, i.e., an ethyl or methyl radical at
the quaternary nitrogen atom in compounds (XI) and
(
XV) did not essentially affect the neuroblocking activꢀ
ity of the compounds under study; the compounds
with paraꢀsubstituted aromatic rings in the linkers of
The most toxic compound within the monoquaterꢀ “dimeric” molecules manifested more noticeable
nized (XVII)–(XXII) was compound (XXI): its LD50 myorelaxing properties than their metaꢀsubstituted
was 4.3 mg/kg, whereas this value for the other comꢀ counterparts; the counterion nature is not important
pounds from this group was within 13.9 to 30.4 mg/kg. for biological properties of the compounds tested.
Also, no basic differences in the biological activity A comparison of biological activity of dimeric quaterꢀ
were found between the pairs of the corresponding nary bases (XV)–(XVI) demonstrated that the lack of
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CURAREꢀLIKE CAMPHOR DERIVATIVES
183
a natural camphor fragment provided the lack of the characteristics of compounds
myorelaxant activity and the appearance of the neuroꢀ described in [18].
(
VII)–(XI
)
were
toxic effect.
The purity of the active substance in the samples
used in biological tests was at least 98%.
Analytical and spectral tests were performed in the
Chemical Service Center for Joint Use, Siberian
Branch of Russian Academy of Sciences.
EXPERIMENTAL
Chemistry
(
E
)ꢀN1,N1ꢀDimethylꢀN2ꢀ((1
bicyclo[2.2.1]heptanꢀ2ꢀyliden)ethanꢀ1,2ꢀdiamine (XIV).
N1 N1ꢀDiethylethanꢀ1,2ꢀdiamine (5.8 g, 66 mmol)
and BF3 Et2O (3.9 mmol) in 3 mL toluene was added
to a solution of (1 )ꢀ(+)ꢀ camphor (10 g, 66 mmol) in
R,4R)ꢀ1,7,7ꢀtrimethylꢀ
We used in this work (
1
R
)ꢀ(+)ꢀcamphor (Alfa
45.5 (СHCl3, s 0.8)), ꢀxylylene
bromide (abcr, 97%), ꢀxylylene bromide (abcr,
N1ꢀdiethylethaneꢀ1,2ꢀdiamine (Sigma,
N1ꢀdimethylethaneꢀ1,2ꢀdiamine (Acros,
25
Aesar, 98%,
⎯
p
[α]D
,
m
⋅
97%), N1
,
R
99%), N1
,
toluene (80 mL) and the reaction mixture was refluxed
for 15 h with a Dean–Stark adaptor. Brine (10 mL)
was added, extracted with methylene chloride, dried
with Na2SO4, and the solvent was evaporated. The resꢀ
99%).
1Н and 13C NMR spectra (
were recorded on a Bruker AVꢀ600 spectrometer (1Н
600.30 MHz, 13С: 150.95 MHz); compounds (XV
XVI), Bruker DRXꢀ500 (1Н: 500.13 MHz, 13С:
δ, J, Hz) of compound (XIV)
:
–
)
idue was distilled in vacuum to give compound (XIV
)
(9.8 g, 67%); bp 98°C (5 mm Hg). 1H NMR: 0.57
(3H, s, Meꢀ9), 0.74 (3H, s, Meꢀ10), 0.77 (3H, s,
Meꢀ8), 1.02 (1H, ddd, 2J = 12.3, J4endo, 5endo = 9.3,
(
125.76 MHz); compounds (XVII)–(XXII), Bruker
AVꢀ400 (1Н: 400.13 MHz, 13С: 100.78 MHz). As interꢀ
nal standards, chloroform (δH 7.24, δС 76.90 ppm),
DMSO (δH 2.50, δС 39.50 ppm) and MeOH (δH 3.31,
δC 49.00 ppm) were used. 1Нꢀ and 13C NMR spectra of
compound (XV) were recorded in a 10 : 1 mixture of
CD3OD and NEt3. The structures of the compounds
synthesized were confirmed using 1Н and 13C NMR
spectra as well as 1Н–1Н double resonance spectra,
twoꢀdimensional homonuclear 1Н–1Н correlation specꢀ
tra (1Н–1Н COSY) and twoꢀdimensional heteronuclear
J4endo,5exo = 4.2
J5endo, 4endo = 9.3, J5endo, 4 exo = 4.5, H5endo), 1.47 (1H,
ddd, 2J
5exo, 4exo = 12.3, 5exo, 4endo = 4.2 H5exo), 1.67
(1H, d, 2J = 16.9, H2exo), 1.67 (1H, dddd, 2J
J4exo, 5exo
12.3, J4exo, 5endo 4exo, 3 = 4.5, 4exo, 2exo = 3.2, H4exo),
1.78 (1H, dd, J3, 2exo J3, 4exo = 4.5, H3), 2.10 (6H, s,
Meꢀ13 and Meꢀ14), 2.18 (1H, ddd, 2J = 16.9, J2exo, 3
4.5, J2exo, 4exo = 3.2 H2exo), 2.35 (2H, t, 12, 11 = 7.6
H12), 3.14 and 3.19 (two 1H, dt, 2J = 12.1,
H11). 13C NMR: 182.18 s (C1), 59.56 t (C12), 53.11 s
(C6), 50.60 t (C11), 46.55 s (C7), 45.51 q (Meꢀ13 and
Meꢀ14), 43.40 d (C3), 35.10 t (C2), 31.80 t (C5),
27.07 t (C4), 19.14 q (Meꢀ9), 18.58 q (Meꢀ10), 11.01
22
q (Meꢀ8).
222.2092 [
,
H4endo), 1.16 (1H, ddd, 2J = 12.3,
=
J
J
,
=
=
=
J
J
=
=
,
J
,
С–Н
13С–1Н correlation (( –COSY, 1JС,Н 160 Hz) specꢀ
2,3
J11, 12 = 7.6,
tra, and distant coupling constants (COLOC,
J
C,H
10 Hz). High resolution mass spectra were recorded
on a DFSThermoScientific spectrometer using the
exhaustive scanning within m/z 0–500; electron
impact ionization (70 eV) with a direct injection of
samples. Final column chromatography was perꢀ
–19.8 (СHCl3,
с
1.1). Found:
222.2091
m/z
[α]D
M
formed on silica gel (60–200 m, MashereyꢀNagel).
μ
]+ C14H26N2. Calc.:
M
.
The HPLC–MS system outfitted with an Agilent
1200 chromatograph and a hybrid quadrupole timeꢀ
ofꢀflight micrOTOFꢀQ massꢀspectrometer (Bruker)
(the APIꢀES mode) was used for the assignment of the
structures of diquaternized compounds. The system
operated in positive polarity with a scanning mass
(
R
,
R
,
E
)ꢀN,N'ꢀ(1,4ꢀPhenylenbis(methylene))bisꢀ
N,Nꢀdimethylꢀ2ꢀ(( )ꢀ((1 ,4 )ꢀ1,7,7ꢀtrimethylbicyꢀ
clo[2.2.1]heptanꢀ2ꢀyliden)amino)ethanaminium)dibroꢀ
mide (XV). ꢀXylylene dibromide (0.26 g, 1 mmol) was
(
E
R R
p
added to a solution of compound (XIV) (0.5 g,
2 mmol) in dry acetonitrile (10 mL), and the mixture
was refluxed for 20 h. The precipitate was filtered off
and loaded onto silica gel column (5 g) eluting with
range of 80 to 3000
rate was 4 L/min; the gas temperature was 190
nebulizing pressure, 1.0 bar. A solution of the comꢀ
pound in methanol (5 L) was injected to the nebuꢀ
lizer of the mass spectrometer. The observed relative
intensities of the isotopic ions and values correꢀ
m/z. The drying gas (nitrogen) flow
°С,
chloroform–ethyl acetate + 1% methanol (100 :
: 100) to give compound (XV) (0.5 g, 35%); mp 207–
210 . In the spectra recorded, the substitution with
0
→
μ
0
°
С
m/z
deuterium in position 2ꢀexo achieved 95%. The resoꢀ
nances of the deuteriumꢀsubstituted compound difꢀ
fered from the unsubstituted are shown with asterix.
lated well with the calculated values for the expected
ions.
The atom numeration serves for the assignment of 1H NMR: 0.80 (6H, s, Meꢀ9), 0.96 (6H, s, Meꢀ8),
resonances in the NMR spectra and does not correlate 0.98 (6H, s, Meꢀ10), 1.28–1.40 (4H, m, H4endo
,
with the numeration according to the chemical H5endo), 1.71–1.79 (2H, m, H5exo), 1.88–1.95 (2H,
nomenclature. The solvents were purified using stanꢀ m, H4exo), 1.98–2.05 (4H, m, H2endo and H3), 2.01
dard protocols. Chloroform for column chromatograꢀ (2H, br s, H2endo*), 2.02.02 (2H, d, J3, 4exo = 4.5, H3*),
phy was washed with aqueous ammonia and dried with 2.53 (2H, ddd, 2J = 16.9,
J2exo, 3 = 4.5,
J2exo, 4exo = 3.2,
calcined molecular sieves. The synthesis and spectral H2exo), 3.21 and 3.21 (6H for each, s, Meꢀ13 and
RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY Vol. 41
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2015

184
SOKOLOVA et al.
Meꢀ14), 3.66–3.72 (4H, m, H12), 3.72–3.83 (4H, m, 129,7 s (C8, 8'), 58,9 t (C7, 7'), 52,3 t (C1, 2, 3, 1', 2',
H11), 4.83 (4H, s, H15), 7.84 (4H, s, H17 and H18). 3'), 6.6 q (Cꢀ4, 5, 6, 4', 5', 6'). (ESI): m/z [M
– Brꢀ]+
13C NMR: 188.59 s (C1), 135.12 d (C17 and C18), 385.219, (calculated for C20H38N2Br) 385.221
.
131.71 s (C16), 68.95 t (C15), 65.20 t (C12), 55.41 t
1,1'ꢀ(1,4ꢀPhenylene)bis(N,N,Nꢀtrimethylmethaꢀ
neaminium) diiodide (XIX). 40% Dimethylamine
(0.5 mL) and K2CO3 (1 g) were added to a solution of
(C6), 51.48 q (C13 and C14), 48.50 s (C7), 47.18 t
(C11), 45.30 d (C3), 45.21 d (C3*), 36.95 t (C2),
36.67 dt (1JC, D = 19.7, CHDꢀ2*), 33.09 t (C5), 28.04
t (C4), 28.01 t (C4*), 19.99 q (C9), 19.26 q (C10),
p
ꢀxylylene dibromide (0.5 g, 2 mmol) in acetonitrile
and the mixture was refluxed for 10 h. 25% NaOH was
added, the mixture was extracted with diethyl ester (3
11.72 q (C8). (ESI):
lated for C36H60N4Br) 627.400,
(calculated for C36H60N4) 274.240
m
/
z
[
M
– Br–]+ 627.394, (calcuꢀ
– 2Brꢀ]2+ 274.239
,
×
[M
20 mL), the organic layer was dried with Na2SO4, and
the solvent was evaporated. Methyl iodide (30 mmol)
was added to a resulting amine solution in acetonitrile,
and the mixture was kept for 4 days at room temperaꢀ
ture. The precipitate was filtered off and dried in air to
.
(
R,R,E)ꢀN,N'ꢀ(1,3ꢀPhenylenbis(methylene))bisꢀ
N,Nꢀdimethylꢀ2ꢀ(( )ꢀ((1R,4R)ꢀ1,7,7ꢀtrimethylbicyꢀ
clo[2.2.1]heptanꢀ2ꢀyliden)amino)ethanaminium) dibroꢀ
mide (XVI). ꢀXylylene dibromide (0.26 g, 1 mmol)
(
E
give compound (XIX) (0.5 g, 50%), mp 281 C.
°
m
1H NMR: 3.14 (18H, s, Meꢀ1, 2, 3, 1', 2', 3'), 4.58
(4H, s, 2H4, 2H4'), 7.71 (4H, s, H6, 7, 6', 7'). 13C
NMR: 135.7 d (C9, 10, 9', 10'), 132.1 s (C8, 8'), 71.0 t
was added to a solution of compound (XIV) (0.5 g,
2 mmol) in dry acetonitrile, and the mixture was
refluxed for 30 h. Compound (XVI) (0.27 g, 20%) was
isolated as described above for compound (XV); mp
(C4, 4'), 54.8 q (C1, 2, 3, 1', 2', 3'). (ESI):
349.112, (calculated for C14H26N2I) 349.114, [
111.102 (calculated for C14H26N2) 111.104
m
/
z
M
[
M
– I–]+
– 2I–]2+
133–136
С. 1H NMR: 0.77 (6H, s, Meꢀ9), 0.93 (6H,
°
.
s, Meꢀ8), 0.95 (6H, s, Meꢀ10), 1.25–1.37 (4H, m,
H4endo, H5endo), 1.66–1.78 (2H, m, H5exo), 1.83–1.93
(2H, m, H4exo), 1.95–2.05 (4H, m, H2endo and H3),
1,1'ꢀ(1,3ꢀPhenylene)bis(N,N,Nꢀtrimethylmethaꢀ
neaminium) dibromide (XX). 40% Trimethylamine
2.51 (2H, ddd, 2J = 16.9,
J2exo, 3 = 4.5, J2exo, 4exo = 3.2,
(1 mL) was added to a solution of
mꢀxylylene dibroꢀ
H2exo), 3.17 (6H, s, Meꢀ13 and Meꢀ14), 3.62–3.68
(4H, m, H12), 3.70–3.82 (4H, m, H11), 4.80 (4H, s,
H15), 7.66–7.76 (1H, m, H18), 7.87–7.95 (2H, m,
H17), 8.08 (1H, s, H19). 13C NMR: 187.1 s (C1),
137.6 d (C17, 17'), 135.08 d (C18, 18'), 129.5 d
(C19,19'), 128.6 s (C16, 16'), 67.4 t (C15, 15'), 63.7 t
(C12), 53.8 s (C6), 49.8 q (C13 and C14), 45.50 s
(C7), 47.18 t (C11), 43.6 d (C3), 35.5 t (C2), 31.5 t
(C5), 29.04 t (C4), 18.5 q (C9, 9'), 17.8 q (C10, 10'),
mide (0.5 g, 2 mmol) in methanol and the mixture was
refluxed for 20 h. The precipitate was filtered off and
dried in air to give compound (XX) (0.26 g, 35%), mp
1
95°
С. H NMR: 3.18 (18H, s, Meꢀ1, 2, 3, 1', 2', 3'),
4.68 (4H, s, 2H4, 2H4'), 7.61–8.04 (4H, m, H6, 7, 8,
6'). 13C NMR: 136.7 d, 135.0 d, 130.0 d, 128.3 s, 68.7
t, 52.4 q. (ESI):
for C14H26N2Br) 301.127, [
culated for C14H26N2) 111.104
m/z [M
– Br–]+ 301.126, (calculated
M
– 2Br–]2+ 111.102 (calꢀ
.
10.2 q (C8, 8'). (ESI):
culated for C36H60N4Br) 627.400,
274.239, (calculated for C36H60N4) 274.240
m/z [
M – Br–]+ 627.396, (calꢀ
N,N'ꢀ(1,3ꢀPhenylene bis(methylene))bis(
thaneaminium) dibromide (XXI). Triethylamine
(0.8 mL, 6 mmol) was added to a solution of
N,Nꢀdiethyleꢀ
[M
– 2Brꢀ]2+
.
mꢀ
1,1'ꢀ(1,4ꢀPhenylene)bis(N,N,Nꢀtrimethylmethaꢀ
neaminium) dibromide (XVII). 40% Trimethylamine
(1 mL) was added to a solution of pꢀxylylene dibroꢀ
xylylene dibromide (0.5 g, 2 mmol) in dry acetonitrile
and the mixture was refluxed for 12 h. The precipitate
was filtered off and dried in air to give compound
(
XXI) (0.5 g, 50%).1H NMR: 1.51 (18H, t, Meꢀ4, 5, 6,
mide (0.5 g, 2 mmol) in methanol and the mixture was
refluxed for 15 h. The precipitate was filtered off and
dried in air to give compound (XVII) (0.32 g, 23%);
4', 5', 6'), 3.39 (12H, q, H1, 2, 3, 1', 2', 3'), 4.68 (4H,
s, H7, 7'), 7.69–7.85 (4H, m, H9, 9', 10, 11).
13C NMR:136.35 d, 134.4 d, 134.39 d, 128.5 s, 59.2 t,
mp >330°C.
1H NMR: 3.04 (18H, s, Meꢀ1, 2, 3, 1', 2',
52.4 t, 6.8 q. (ESI):
lated for C20H38N2Br) 385.221, [
(calculated for C20H38N2) 153.151
m/z [M
– Br–]+ 385.222, (calcuꢀ
3'), 4.48 (4H, s, H4, H4'), 7.62 (4H, s, H6, 7, 6', 7').
13C NMR: 133.10 d (C6, 7, 6', 7'), 129,5 s (C5, 5'),
M
.
– 2Br–]2+ 153.152
68,4 t (C4, 4'), 52,3 q (C1, 2, 3, 1', 2', 3'). (ESI):
– Br–]+ 301.127, (calculated for C14H26N2Br)
301.127
m/z
[M
1,1'ꢀ(1,3ꢀPhenylene)bis(N,N,Nꢀtrimethylmethaꢀ
neaminium) diiodide (XXII). 40% Dimethylamine
.
N,N'ꢀ(1,4ꢀPhenylenebis(methylene))bis(N,Nꢀdiethꢀ (0.5 mL) was added to a solution of
ylethaneaminium) dibromide (XVIII). Trimethylamine mide (0.5 g, 2 mmol) in acetonitrile and the mixture
(0.8 mL, 6 mmol) was added to a solution of ꢀxylylene was refluxed for 10 h in the presence of K2CO3 (1 g).
dibromide (0.5 g, 2 mmol) in dry acetonitrile and the The mixture was treated with 25% NaOH and
mixture was refluxed for 8 h. The precipitate was filꢀ extracted with diethyl ester ( 20 mL). The organic
mꢀxylylene dibroꢀ
p
3
×
tered off and dried in air to give compound (XVIII
(0.71 g, 40%); mp 270
C. 1H NMR: 1.43 (18H, t,
7.06, Meꢀ4, 5, 6, 4', 5', 6'), 3.32 (12H, t,
)
J =
layer was dried, and the solvent was evaporated. The
precipitate was filtered off, the resulting tertiary amine
°
J
= 7.2, H1, (0.4 g) was dissolved in dry acetonitrile, and methyl
2, 3, 1', 2', 3'), 4.55 (4H, s, 2H7, 2H7'), 7.70 (4H, s, iodide (20 mmol) was added. The mixture was kept for
H9, 10, 9', 10'). 13C NMR: 133.07 d (C9, 10, 9', 10'), 2 days at room temperature. The precipitate was filꢀ
RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY Vol. 41
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2015

CURAREꢀLIKE CAMPHOR DERIVATIVES
185
5. Korochkina, M.G., Nikitashina, A.D., Khaybullin, R.N.,
Petrov, K.A., Strobykina, I.Yu., Zobov, V.V., and
Kataev, V.E., Med. Chem. Commun., 2012, vol. 3,
pp. 1449–1454.
tered off and dried in air to give the target compound
XXII) (0.6 g, 60%), mp 215
1H NMR: 3.15 (18H, s,
(
°С.
Meꢀ1, 2, 3, 1', 2', 3'), 4.60 (4H, s, H4,4'), 7.68–7.82
(4H, m, H6, 7, 6', 8). 13C NMR: 136.7 d, 135.0 d,
130.0 d, 128.3 s, 68.7 t, 52.4 q. (ESI): m/z [M
– I–]+
6. Salakhutdinov, N.F. and Tolstikov, G.A., MiniꢀRev.
Med. Chem., 2010, vol. 10, no. 13, pp. 1248–1262.
349.111, (calculated for C14H26N2I) 349.114
.
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Primary experiments on the evaluation of the bioꢀ
logical activity of the compounds tested were perꢀ
formed on male outbred mice 25–30 g in weight. The
compounds were administered as aqueous solutions at
doses 5 to 20 mg/kg. Median lethal doses, LD50, were
taken as toxicity indices (experimental time of 72 h);
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and inclined plate, as indices of the myorelaxant activꢀ
ity [19]. Each group had 6 to 8 animals. Control aniꢀ
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ical solution, 0.1 mL/10 g body weight.
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2015