Note: Descriptions are shown in the official language in which they were submitted.
CA 02485545 2004-11-18
81179fft
BOEHRINGER INGELHEIM PHARMA KG Case 1/1357
D-55216 Ingelheim foreign filing text
(R)-2-(4-amidinophenylaminomethyl)-1-methyl-5-[1-(carboxymethylamino)-
1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole, the monohydrochloride thereof,
preparation thereof and the use as pharmaceutical composition
The present invention relates to the crystalline forms of the compounds (R)-2-
(4-
amidinophenylaminomethyl)-1-methyl-5-[1-(carboxymethylamino)-
1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole and the monohydrochloride
thereof,
processes for the preparation thereof and the use thereof as pharmaceutical
compositions.
Background to the invention
A number of benzimidazole derivatives are known in the prior art. Thus, for
example,
International Patent Application WO 00/01704 discloses benzimidazole
derivatives
which have valuable pharmacological properties, particularly an antithrombotic
activity,
which is based, for example, on a thrombin-inhibiting or factor Xa-inhibiting
activity.
By virtue of their pharmacological properties, the compounds (R)-2-(4-
amidinophenyl-
aminomethyl)-1-methyl-5-[1-(carboxymethylamino)-1-(pyrrolidinocarbonyl)-ethylJ-
benzimidazole and the monohydrochloride thereof may be used for the prevention
and
treatment of venous thromboses in various vascular areas, including deep and
superficial leg vein thromboses, vena cava thromboses, thromboses of the renal
and
hepatic veins including veno-occlusive disease, for the prevention and
treatment of
pulmonary embolism, for the treatment of patients with all forms of coronary
heart
disease, including the acute form, as unstable angina pectoris or acute
myocardial
infarct, and the chronic form, as stable angina pectoris, or in patients with
post-
myocardial infarct condition, for preventing acute and chronic reocclusions
after bypass
operations on all vascular areas and after angioplasty (PT(C)A), and for
preventing
occlusion in patients with peripheral arterial diseases, for treating stroke
in its acute
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form, in the chronic form in patients with post-stroke conditions and for
primary
prophylaxis in patients with stenoses of the afferent cerebral arteries.
The benzimidazoles mentioned above may also be used to treat patients on
kidney
replacement therapy. This comprises both anticoagulation during the use of
kidney
replacement therapy to keep the system open and also treatment of the system
activation of clotting such as occurs in patients on kidney replacement
therapy, both in
patients undergoing chronic haemodialysis and in those undergoing a process of
veno-
venous or arterio-venous chronic filtration. Accordingly, both patients with
chronic
kidney failure and patients with acute kidney failure may be treated
irrespective of the
cause of the kidney failure. This also includes the prevention and treatment
of blockage
of the dialysis shunt.
The abovementioned pharmacologically valuable properties of the benzimidazole
I S derivatives disclosed in the prior art constitute the basic prerequisite
for effective use of
the compounds as pharmaceutics! compositions. However, to be permitted for use
as a
medicament, an active substance must also satisfy further requirements. These
parameters are largely to do with the physicochemical nature of the active
substance.
Without being restrictive, examples of these parameters are the stability of
effect of the
starting substance under various environmental conditions, the stability
during
production of the pharmaceutical formulation and stability in the final
compositions of
the drug. The pharmaceutically active substance used to prepare the
pharmaceutical
compositions should therefore have great stability which is ensured even under
all kinds
of environmental conditions. This is absolutely essential to prevent
pharmaceutical
compositions being used which contain breakdown products, for example, in
addition to
the active substance itself. In such a case the content of active substance
present in
the pharmaceutical formulation might be lower than specified.
The absorption of moisture reduces the content of pharmaceutically active
substance as
a result of the increased weight caused by the uptake of water. Pharmaceutical
compositions with a tendency to absorb moisture have to be protected from
moisture
during storage, e.g. by the addition of suitable drying agents or by storing
the drug in an
environment where it is protected from moisture. In addition, the uptake of
moisture
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may reduce the content of pharmaceutically active substance during manufacture
if the
pharmaceutical substance is exposed to the environment without being protected
from
moisture in any way. Preferably, therefore, a pharmaceutically active
substance should
be only slightly hygroscopic.
As the crystal modification of an active substance is important to the
reproducible active
substance content of a preparation, there is a need to clarify as far as
possible any
existing polymorphism of an active substance present in crystalline form. If
there are
different polymorphism modifications of an active substance care must be taken
to
ensure that the crystalline modification of the substance does not change in
the
pharmaceutical preparation later produced from it. Otherwise, this could have
a harmful
effect on the reproducible potency of the drug. Against this background,
active
substances characterised by only slight polymorphism are preferred.
Another criterion which may be of exceptional importance under certain
circumstances
depending on the choice of formulation or the choice of manufacturing process
is the
solubility of the active substance. If for example pharmaceutical solutions
are prepared
(e.g. for infusions) it is essential that the active substance should be
sufficiently soluble
in physiologically acceptable solvents. It is also very important for drugs
which are to be
taken orally that the active substance should be sufficiently soluble.
The problem of the present invention is to provide a pharmaceutically active
substance
which not only is characterised by high pharmacological potency but also
satisfies the
above-mentioned physicochemical requirements as far as possible.
Detailed description of the invention
Surprisingly, it has been found that the problem outlined above is solved by
the
crystalline monohydrochloride of the compound (R)-2-(4-
amidinophenylaminomethyl)-1-
methyl-5-[1-(carboxymethylamino)-1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole
of
formula (I):
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O
O
H C NH~
HZN H s . z
(+7 ~ ~ N N ~ O CI~
HZN ~~ ~ ~ N
N U
H3C
(I)
The monohydrochloride according to the invention is characterised by a high
degree of
stability and dissolves very easily in physiologically acceptable solvents.
The crystalline form of the monohydrochloride of the compound (R)-2-(4-
amidinophenylaminomethyl)-1-methyl-5-[1-(carboxymethylamino)-1-(pyrrolidino-
carbonyl)-ethyl] according to the invention is characterised by a melting
point of Tm.P, _
222°C ~ 5°C (determined by DSC = Differential Scanning
Calorimetry; evaluated by the
onset; heating rate: 10°C/min). The value given was determined using a
DSC 821
made by Messrs Mettler Toledo.
Therefore a first object of the present invention is the crystalline
monohydrochloride of
the compound (R)-2-(4-amidinophenylaminomethyl)-1-methyl-5-[1-(carboxy-
methylamino)-1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole, characterised by a
melting
point Of Tn,.P. = 222°C ~ 5°C.
The crystalline form of the (R)-2-(4-amidinophenylaminomethyl)-1-methyl-5-[1-
(carboxymethylamino)-1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole
monohydrochloride
according to the invention was examined more closely by X-ray powder
diffraction. The
diagram obtained is shown in Figure 1.
Table 1 that follows summarises the data obtained in this analysis:
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Table 1: X-ray powder reflections and intensities (standardised) of (R)-2-(4-
amidinophenylaminomethyl)-1-methyl-5-[1-(carboxymethylamino)
1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole-monohydrochloride.
2 O dhkl intensity 2 O dhkl intensity
I1 [~41 ulo I%] I1 Ill ulo [%]
9.17 9.64 13 22.66 3.92 12
10.21 8.66 19 23.50 3.78 15
11.28 7.84 21 23.90 3.72 30
13.06 6.77 11 24.22 3.67 18
13.34 6.63 16 24.51 3.63 16
14.03 6.31 100 25.33 3.51 19
14.57 6.07 38 25.63 3.47 16
15.62 5.67 23 26.04 3.42 9
17.22 5.14 34 27.83 3.20 12
18.45 4.80 14 29.76 3.00 10
18.63 4.76 16 31.10 2.87 12
19.19 4.62 16 32.39 2.76 8
19.78 4.48 13 32.98 2.71 11
20.45 4.34 14 33.32 2.69 12
20.99 4.23 12 33.89 2.64 10
21.24 4.18 17 35.73 2.51 9
22.39 3.97 14 36.34 2.47 8
In Table 1 above the value "2 O [°]" denotes the angle of diffraction
in degrees and the
value "dhkl [~]" denotes the specified distances in A between the lattice
planes.
The x-ray powder diagram was recorded, within the scope of the present
invention,
using a Bruker D8 Advanced Diffractometer fitted with a location-sensitive
detector
(OED) and a Cu anode as the x-ray source (CuICa radiation, ~, = 1.5418 A, 30
kV, 40
mA).
According to the findings shown in Table 1 the present invention relates to
crystalline
(R)-2-(4-amidinophenylaminomethyl)-1-methyl-5-[1-(carboxymethylamino)-
1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole-monohydrochloride, characterised
in that in
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the x-ray powder diagram it has, inter alia, the characteristic values d =
6.31 A, 6.07 A,
5.14 A and 3.72 A.
The crystalline monohydrochloride of the compound (R)-2-(4-
amidinophenylaminomethyl)-1-methyl-5-[1-(carboxymethylamino)-1-
(pyrrolidinocarbo-
nyl)-ethyl]-benzimidazole according to the invention occurs in the form of
hydrates
which, depending on the relative humidity, contain between about 3.0% and 6.5%
water. By virtue of its structure the compound is capable of absorbing water
of
crystallisation and releasing it again without the crystalline structure
changing
fundamentally.
Moreover, the monohydrochloride according to the invention forms solvates with
organic
solvents, e.g. with ethanol.
A second object of the present invention is a process for preparing the
crystalline salt
(R)-2-(4-amidinophenylaminomethyl)-1-methyl-5-[1-(carboxymethylamino)-
1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole-monohydrochloride according to
the
invention, comprising the following steps:
Ste a
The starting material used is the (R)-2-(4-cyanophenylaminomethyl)-1-methyl-5-
[1-
amino-1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole of formula (II) already
described in
WO 00/01704:
H3C, NHZ
N ~ O
r
NC ~ \ N~N ~ N
~H
H3C II
()
The free primary amino group is alkylated for example with 1 to 1.5
equivalents,
preferably with about 1.2 equivalents, of a compound of general formula
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O
X OR , (III)
wherein R denotes a C~_3-alkyl group and X denotes a leaving group, for
example a
halogen atom such as the chlorine, bromine or iodine atom, the p-
toluenesulphonyl or
methanesulphonyl group, of which ethyl bromoacetate or n-propyl bromoacetate
is
preferably used, in an organic solvent or mixture of solvents, in the presence
of a base.
Suitable solvents according to the invention include ethyl acetate, n-propyl
acetate,
N-methylpyrrolidinone, dimethylformamide, dimethylacetamide or mixtures
thereof.
According to the invention, a solvent mixture consisting of N-
methylpyrrolidinone and
ethyl acetate or n-propyl acetate is used. Suitable bases include for example
tertiary
amines such as diisopropylethylamine (Hunig base) or triethylamine in an
amount of 1
to 2.5 equivalents. The reaction is preferably carried out at temperatures
between 0°C
and the boiling temperature of the solvent mixture, e.g. between 0°C
and 150°C,
preferably between 10°C and 30°C.
Purification of the reaction mixture through aqueous extractions yields, after
partial
evaporation of the organic solvent, a concentrated solution of crude (R)-2-(4-
cyanophenylaminomethyl)-1-methyl-5-[1-(n-C~_3-alkyloxycarbonylmethylamino)-
1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole of general formula
O
H3C, N~ R
N ~ O
NC ~ ~ N~N ~ ~ <N>
~H
H3c U
(IV)
wherein R denotes a C~_3-alkyl group.
Ste b
The concentrated solution of the crude compound of formula (IV) obtained in
step (b) is
dissolved in a C~_3-alcohol as solvent and reacted by piping in hydrogen
chloride gas,
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with cooling, preferably at a temperature below about 20°C, to produce
the imino ester
as intermediate. According to the invention methanol, ethanol or n-propanol is
preferably used as alcohol, while the choice of solvent depends on the ester
of formula
(IV) used. Once all the hydrogen chloride gas has been piped in the reaction
mixture is
stirred until the reaction is complete at a temperature between 0°C and
30°C, preferably
at about 20°C.
The conversion of the iminoester into an amidine of general formula
O
O
HC N~ R
3 .
O
H2N ~ ~ N~N I / N
HN H H3C U V
( )
wherein R denotes a C~_3-alkyl group,
is carried out with cooling, preferably at temperatures between 0°C and
40°C, most
preferably at 15°C to 40°C, by reacting with an aqueous ammonia
solution in a
C~_3-alcohol, preferably methanol, ethanol or n-propanol. Once the reaction
has ended,
to obtain the amidine, ammonium chloride may be filtered off optionally after
partial
distillation of the solvent. The compound (V) may be intermediately isolated
in the form
of the hydrochloride or directly as the p-toluenesulphonic acid salts of
general formula
(VI) (cf. step c).
Ste c
The intermediate compounds (R)-2-(4-amidinophenylaminomethyl)-1-methyl-5-[1-(n-
C,_3-alkyloxycarbonylmethylamino)-1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole
of
general formula (V) are precipitated according to the invention in the form of
sulphonic
acid salts, for example in the form of benzene-, p-toluene-, p-chlorobenzene-,
1- or 2-
naphthenesulphonic acid salts, most preferably in the form of the the p-
toluenesulphonic
acid salts of general formula (VI)
CA 02485545 2004-11-18
_g_
O
S03H p
HN HC N~ \R
z ~ ~ N N ~ ~ p
/ HN
CH3 H C
~U
s , (VI)
wherein R denotes a C~_3-alkyl group, enabling the compound to be easily
isolated from
the aqueous medium.
Further purification of the p-toluenesulphonic acid salts of the compounds of
general
formula (VI) is carried out by pH-controlled dissolving and precipitation of
the salt in
aqueous medium or by suspending in water.
Ste d
In order to prepare the free base (R)-2-(4-amidinophenylaminomethyl)-1-methyl-
5-[1-
(carboxymethylamino)-1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole of formula
O
~OH
HzN ~ ~ H HsC, N O
N N
HN
N ~ U
H3C , (VII)
the corresponding p-toluenesulphonic acid salt of general formula (VI) is
dissolved in a
suitable organic solvent. Suitable solvents include for example alcohols such
as
methanol, ethanol, i-propanol or polar solvents such as N-methylpyrrolidinone
or
dimethylformamide, preferably methanol or ethanol.
Then 1.5 to 3 equivalents, preferably 2 to 2.5 equivalents of a suitable base
are added
to this solution. Suitable bases within the scope of the present invention
include sodium
hydroxide, potassium hydroxide, lithium hydroxide and barium hydroxide.
The reaction mixture can then be heated and in this way the progress of the
reaction
can be speeded up. Preferably, the reaction mixture is heated, with thorough
mixing, to
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a temperature above 30°C, the maximum temperature which can be selected
depending on the boiling temperature of the solvent used, preferably at
temperatures
between 30°C and 80°C.
Then 0.5 to 2 equivalents, preferably 1 to 1.5 equivalents, of an acid,
preferably
p-toluenesulphonic acid, are added.
If sodium hydroxide is used as the base, the desired product of formula (VII)
is obtained
directly on crystallisation. If potassium hydroxide is used as base, the
potassium salt of
p-toluenesulphonic acid crystallises out first. Then the desired product of
formula (VII)
can be crystallised.
Ste a
In order to prepare the crystalline monohydrochloride of general formula (I)
according to
the invention the base (VII) obtained in step (d) is suspended or dissolved in
a suitable
organic solvent or mixture of solvents. Particularly preferred solvents
according to the
invention include methanol, ethanol, n-propanol, i-propanol, acetone,
dimethylformamide or N-methylpyrrolidinone. A certain amount of water may be
added
as cosolvent.
Then the reaction mixture is heated to a temperature between 20°C and
the reflux
temperature of the solvent, preferably between 30°C and 80°C .
According to the
invention, hydrogen chloride dissolved in an organic solvent or hydrochloric
acid is
added to the solution or suspension.
According to the invention 0.8 to 1.2 mol, preferably about 1 mol, of hydrogen
chloride
are added per mol of base used. After the acid has been added the suspension
is
cooled to a temperature between 0°C and 40°C, preferably between
20°C and 25°C
and the product is filtered off.
A third object of the invention relates to crystalline (R)-2-(4-
amidinophenylaminomethyl)-
1-methyl-5-[1-(carboxymethylamino)-1-(pyrrolidinocarbonyl)-ethyl]-
benzimidazole-
monohydrochloride, obtainable by the process described hereinbefore.
A fourth object of the invention is the use of the crystalline
monohydrochloride of the
compound (R)-2-(4-amidinophenylaminomethyl)-1-methyl-5-[1-(carboxymethylamino)-
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1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole according to the invention as a
pharmaceutical composition on account of its pharmaceutical activity.
The p-toluenesulphonic acid salts of general formula (VI) obtained as
intermediates in
the process described above are valuable intermediate products for preparing
the
crystalline (R)-2-(4-amidinophenylaminomethyl)-1-methyl-5-[1-
(carboxymethylamino)-
1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole-monohydrochloride of formula (I).
A fifth object of the present invention thus consists of the p-
toluenesulphonic acid salts
of general formula (VI):
(1) (R)-2-(4-amidinophenylaminomethyl)-1-methyl-5-[1-(methyloxycarbonylmethyl
amino)-1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole-p-toluenesulphonate,
(2) (R)-2-(4-amidinophenylaminomethyl)-1-methyl-5-[1-(ethyloxycarbonylmethyl-
amino)-1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole-p-toluenesulphonate and
(3) (R)-2-(4-amidinophenylaminomethyl)-1-methyl-5-[1-(n-propyloxycarbonyl-
methylamino)-1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole-p-toluenesulphonate.
The crystalline form of the free base (R)-2-(4-amidinophenylaminomethyl)-1-
methyl-5-
[1-(carboxymethylamino)-1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole is the
direct
precursor for preparing the monohydrochloride of formula (I) and also has the
pharmacological activity described hereinbefore.
A sixth object of the present invention is therefore the crystalline form of
the free base
(R)-2-(4-amidinophenylaminomethyl)-1-methyl-5-[1-(carboxymethylamino)-
1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole, characterised by a melting point
Tm.P. _
241 °C ~ 5°C (determined by DSC = Differential Scanning
Calorimetry; evaluated by the
onset; heating rate: 10°C/min). The value given was determined using a
DSC 821
made by Messrs Mettler Toledo.
The crystalline form of the free base (R)-2-(4-amidinophenylaminomethyl)-1-
methyl-5-
[1-(carboxymethylamino)-1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole according
to the
CA 02485545 2004-11-18
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invention was investigated in more detail by x-ray powder diffraction. The
diagram
obtained is shown in Figure 2.
Table 2 which follows summarises the data obtained in this analysis:
Table 2: X-ray powder reflections and intensities (standardised) of (R)-2-(4-
amidinophenylaminomethyl)-1-methyl-5-[1-(carboxymethylamino)-
1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole.
2 O dhkl intensity 2 O dhkl intensity
I) I~l uto [l] I1 I~1 I/lo [%]
7.331 12.04817 11.9 21.500 4.12969 15.8
10.804 8.18223 7.5 22.240 3.99395 7.9
11.572 7.64093 12.3 23.308 3.81335 19.4
12.312 7.18300 4.2 23.738 3.74525 9.4
12.976 6.81712 7.6 24.308 3.65862 8.2
13,726 6.44632 5,9 24.890 3.57442 8.3
14.295 6.19076 17.9 25.131 3.54076 7.9
14.726 6.01067 100.0 26.503 3.36044 4.7
15.365 5.76201 6.7 27.204 3.27547 7.3
17.168 5.16080 29.4 27.786 3.20815 9.6
18.014 4.92041 11.3 28.530 3.12608 7.5
18.309 4.84161 9.2 29.678 3.00774 6.3
19.168 4.62671 7.1 30.962 2.88589 5.0
20.224 4.38744 8.8 32.412 2.76004 4.3
In Table 1 above the value "2 O [°]" denotes the angle of diffraction
in degrees and the
value "dhkl [~]" denotes the specified distances in A between the lattice
planes.
The x-ray powder diagram was recorded, within the scope of the present
invention,
using a Bruker D8 Advanced-diffractometer fitted with a location-sensitive
detector
(OED) and a Cu anode as the x-ray source (CuKa, radiation, ~, = 1.5418 A, 30
kV, 40
mA).
According to the findings shown in Table 2 the present invention relates to
crystalline
(R)-2-(4-amidinophenylaminomethyl)-1-methyl-5-[1-(carboxymethylamino)-
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1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole, characterised in that in the x-
ray powder
diagram it has, inter alia, the characteristic values d = 6.19 A, 6.01 A, 5.16
A, 4.13 A
and 3.81 A.
The invention further relates to the use of the crystalline base (R)-2-(4-
amidinophenylaminomethyl)-1-methyl-5-[1-(carboxymethylamino)-1-(pyrrolidi-
nocarbonyl)-ethyl]-benzimidazole according to the invention as a
pharmaceutical
composition on account of its pharmaceutical activity.
Solid stress stability data of the free base and of the corresponding
monohydrochloride
Stress Storage Stress Storagemonohydro- Free base
Parametersmethod conditionstime chloride
temperatureopen glass105 C 24 hoursno decomp- approx.
1
dish osition decomposition
temperatureopen glass70C; approx.3 days no decomp- approx.
4
and relativedish 90 % relative osition decomposition
humidity humidi
light open glassSuntester 22 - no significantapprox.
24 1
dish xenon lamphours decompositiondecomposition
(< 1 %)
CA 02485545 2004-11-18
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Experimental section
The HPLC data given below were measured under the following parameters, unless
otherwise stated:
Column: Prontosil 120-5-C18AQ, 5 pm, 125x4 mm; solvent A: 0.2°I°
aqueous KHZP04
solution, adjusted to pH = 5.5 with 1 M NaOH; solvent B: acetonitrile; column
temperature: 45°C; flow: 1 mL/min; gradient system: up to 2 min 10%
solvent B; within
14 min gradient to 60% solvent B, within 4 min gradient to 80% solvent B;
concentration
of the sample solution: 2 mg/mL in acetonitrile/water = 7:3; injection volume:
1 pL;
detection at 220 nm.
Exami Ip a 1:
(R)-2-(4-amidinophenylaminomethyl)-1-methyl-5-[1-(n-
propyloxycarbonylmethylamino)-
1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole-p-toluenesulphonic acid salt
442 g (2.09 mol) of n-propyl bromoacetate are poured into a solution of 700 g
(1.74 mol)
of (R)-2-(4-cyanophenylaminomethyl)-1-methyl-5-[1-amino-1-
(pyrrolidinocarbonyl)-
ethylj-benzimidazole and 700 mL of diisopropylethylamine in 1.4 L of N-
methylpyrrolidinone and 1.4 L of n-propylacetate within 15 minutes at
20°C. The
reaction mixture is stirred for 14 hours at 20°C. 2.1 L of n-
propylacetate and 5.6 L of
water are added. The mixture is cooled to 20°C and the aqueous phase is
separated
off. 3.5 L of water are added to the organic phase and this is adjusted to a
pH of pH =
5.8 by the addition of 30% hydrochloric acid. The aqueous phase is separated
off. 3.5 L
of water and 105 g of sodium chloride are added to the organic phase with
stirring. The
aqueous phase is separated off. The organic phase is concentrated by
evaporation
under reduced pressure using the rotary evaporator. 0.9 L of n-propylacetate
and 3.5 L
of n-propanol are added to the resulting oil. Another 3 litres of solvent are
distilled off
under reduced pressure.
3.5 L n-propanol are added to the residue and cooled to -15°C. 1.92 kg
of hydrogen
chloride gas are piped through this solution so that the temperature does not
exceed
8°C. After the introduction of gas has ended the reaction mixture is
stirred for 20 hours
at 20°C. Then the reaction solution is cooled to 10°C. The
reaction solution is stirred
CA 02485545 2004-11-18
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into a solution of 4.53 L of a 25% aqueous ammonia solution in 7 L of n-
propanol cooled
to -20°C, while the temperature is kept below 20°C. The reaction
mixture is stirred for
16 hours at 24 °C. 5.8 L of solvent are distilled off under reduced
pressure. The reaction
mixture is cooled to 45°C and filtered through a pressure filter. The
pressure filter is
washed with 3.5 L of hot n-propanol. 8.8 L of solvent are distilled off from
the filtrate in a
rotary evaporator under reduced pressure. The residue remaining is suspended
with 7 L
acetone while heating and refluxing. The suspension is cooled to 0°C
and stirred for
one hour at this temperature. The suspension is suction filtered and washed
with 2.8 L
acetone. The filter cake is dried at 50°C in the circulating air drier.
1.23 kg of (R)-2-(4-
amidinophenylaminomethyl)-1-methyl-5-[1-(n-propyloxycarbonyfmethylamino)-1-
(pyrrolidinocarbonyl)-ethyl]-benzimidazole-hydrochloride are obtained
HPLC: Rf= 9.9 min (product)
Rf = 12.9 min (bisalkylated by-product)
Precipitation as p-toluenesulahonic acid salt:
1.22 kg of the crude hydrochloride described above are dissolved with stirring
in 1.05 L
n-propanol and 5.6 L water by heating to 55°C. To this solution is
added a solution of
530 g of p-toluenesulphonic acid monohydrate and 146 mL of a 50% sodium
hydroxide
solution in 4.2 L of water. The resulting mixture is cooled to 0°C and
stirred for 30
minutes at this temperature. The suspension is suction filtered and washed
with 3.5 L of
water. The filter cake is dried in the circulating air drier at 50°C.
0.70 kg of the p-
toluenesulphonic acid salt of the title compound are obtained as a crude
product.
HPLC: Rf = 3.6 min (p-toluenesulphonic acid)
Rf = 9.9 min (product)
Rf = 12.9 min (bisalkylated by-product)
A further 0.19 kg of product are isolated from the mother liquor by adjusting
the pH to
pH = 7.5 with 25% ammonia solution.
Total yield: 0.89 kg (73% of theory)
CA 02485545 2004-11-18
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Further purification of thep-toluenesulphonic acid salt:
1.1 kg of the crude product of the p-toluenesulphonic acid salt described
above are
suspended in 13.2 L water at 20°C. 151 g of p-toluenesulphonic acid and
328 mL of
30% hydrochloric acid are added, whereupon the solid goes into solution and a
pH of 1
to 1.5 is obtained. The pH is adjusted to 4 by the addition of 25% ammonia
solution
(approx. 170 mL). The resulting suspension is stirred for 19 hours at
20°C. The
precipitate (bisalkylated by-product) is filtered off. The filter cake is
washed with 2.2 L
water. 1.54 L of n-propanol are added to the filtrate followed by 130 mL of
25%
ammonia solution. The suspension is stirred overnight at 20°C. The
precipitate is
suction filtered and washed with 3.3 L water. The filter cake is dried at
50°C in the
circulating air drier. 0.83 kg (76% of theory) of the title compound are
obtained.
HPLC: Rf = 3.6 min (p-toluenesufphonic acid)
Rf= 9.9 min (product)
Example 2: Method of preparing the free base by ester cleaving with sodium
hydroxide
starting from the p-toluenesulphonic acid salt of the n-propyl ester
(R)-2-(4-amidinophenylaminomethyl)-1-methyl-5-[1-(carboxymethylamino)-1-
(pyrroli-
dinocarbonyl)-ethyl]-benzimidazole
To a solution of 27.7 g (40 mmol) of (R)-2-(4-amidinophenylaminomethyl)-1-
methyl-5-[1-
(n-propyloxycarbonylmethyfamino)-1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole-
p-
toluenesulphonate in 134 mL of methanol are added 3.36 g (84 mmol) of solid
sodium
hydroxide and the mixture is refluxed for 3 hours. 8.37 g (44 mmol) of p-
toluenesulphonic acid hydrate are added and the mixture is rei~uxed for a
further 1.5
hours. The solution is allowed to cool to 40°C and filtered (clear
filtration). 170 mL
methanol are added to the filtrate and it is inoculated. The suspension formed
is stirred
overnight at 20°C. The suspension is suction filtered and the filter
cake is washed with
60 mL methanol. The product is dried in the circulating air drier at
40°C. The title
compound is obtained as a crystalline solid.
Yield: 13.8 g (72% of theory)
melting point: Tm.P,. = 249°C ~ 5°C (decomposition, DSC,
evaluating using onset,
heating rate: 10°Clmin )
CA 02485545 2004-11-18
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Example 3: Method of preparing the free base by ester cleaving with sodium
hydroxide
starting from the hydrochloride salt of the n-propyl ester
(R)-2-(4-amidinophenylaminomethyl)-1-methyl-5-[1-(carboxymethylamino)-1-
(pyrroli-
dinocarbonyl)-ethyl]-benzimidazole
To a solution of 93.9 g (0.15 mot) of (R)-2-(4-amidinophenylaminomethyl)-1-
methyl-5-[1-
(n-propyloxycarbonylmethylamino)-1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole-
hydrochloride x 1 equivalent n-propanol in 470 mL methanol are added 13.3 g
(0.33
mol) of solid sodium hydroxide and this mixture is refluxed for 1.5 hours
under an inert
gas atmosphere. It is allowed to cool to 50°C and within 10 minutes
22.8 mL (0.18
mmol) of chlorotrimethylsilan are added dropwise thereto. The mixture is
diluted with
470 mL of dimethylsulphoxide and 370 mL of methanol are distilled off at 300
mbar /
80°C. To eliminate sodium chloride the suspension is filtered hot. The
filtrate is cooled
to 20°C and stirred for 3 hours at 20°C. The suspension formed
is suction filtered and
the filter cake is washed with 50 mL dimethylsulphoxide and 100 mL acetone.
The filter
cake is dried at 50°C in the circulating air drier. The title compound
is obtained as a
colourless solid.
Yield: 58.8 g (81 % of theory)
For further purification the product thus obtained may be crystallised from
methanol.
melting point: Tm,p_ = 241 °C ~ 5°C (decomposition, DSC,
evaluated via onset,
heating rate: 10°C/min)
Examlole 4: Method of precipitating the monohydrochloride from the free base
(R)-2-(4-amidinophenylaminomethyl)-1-methyl-5-[ 1-(carboxymethylamino)-1-
(pyrroli-
dinocarbonyl)-ethyl]-benzimidazole-monohydrochloride
A suspension of 11 g (23 mmol) of (R)-2-(4-amidinophenylaminomethyl)-1-methyl-
5-[1-
(carboxymethylamino)-1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole in 88 mL
methanol
is heated to 35°C to 40°C. To this suspension are added 8.4 mL
of a 2.75 molar
solution of hydrogen chloride (23 mmol) in ethyl acetate. The starting
material is
dissolved and the hydrochloride begins to crystallise out. The suspension is
cooled to
CA 02485545 2004-11-18
-18-
20°C and suction filtered. The filter cake is dried in the vacuum
drying cupboard at
35°C. 9.2 g (78% of theory) of the title compound are obtained as a
crystalline solid.
To eliminate traces of methanol 8 g of the title compound obtained above are
suspended in 80 mL of ethanol and stirred for 30 minutes at 50°C. The
suspension is
cooled to 20°C and suction filtered. The filter cake is washed with
ethanol and dried in
the vacuum drying cupboard at 35°C.
Yield: 7.3 g (91% of theory based on hydrochloride used)
melting point: Tm.P., = 222°C ~ 5°C (decomposition, DSC,
evaluated via onset,
heating rate: 10°C/min)
Example 5:
(R)-2-(4-Amidinophenylaminomethyl)-1-methyl-5-( 1-(ethyloxycarbonylmethylami
no)-1-
(pyrrolidinocarbonyl)-ethyl]-benzimidazole-p-toluenesulphonic acid salt
4.22 kg (10.5 mol) of (R)-2-(4-cyanophenylaminomethyl)-1-methyl-5-(1-amino-1-
(pyrroli-
dinocarbonyl)-ethyl]-benzimidazole and 3.11 kg (24.1 mol) of
diisopropylethylamine are
dissolved in a mixture of 8.4 L of N-methylpyrrolidinone and 8.4 L of
ethylacetate. 2.1 kg
(12.6 mol) of ethyl bromoacetate are metered in and the mixture is stirred for
15 hours
at 20°C. 34 L of water are added. The aqueous phase is separated off.
21 L of water
are added to the organic phase and the pH is adjusted to 5.7 by the addition
of
hydrochloric acid (30%). The aqueous phase is separated off and the organic
phase is
washed with a solution of 0.42 kg of sodium chloride in 21 L of water. The
organic
phase is concentrated under reduced pressure (10.6 L of ethyl acetate are
distilled off).
The concentrate is diluted with 42 L of ethanol and concentrated again under
reduced
pressure (21 L are distilled off). At 20°C 15 kg (411 mol) of
hydrochloric acid gas are
piped into the resulting solution and it is stirred at 20°C until the
reaction is complete
(the reaction to obtain the iminoester is monitored by HPLC). The iminoester
solution
formed is diluted with 25 L of ethanol. 37.8 kg (555 mol) of ammonia solution
(25%) are
added to the solution so that the temperature does not exceed 40°C. The
solution is
then stirred for 2 hours. The ammonium chloride formed is filtered through a
pressure
filter and the filtered material is washed with 30 L of ethanol. 42 L of
ethanol are distilled
off from the filtrate under reduced pressure. A solution of 3.86 kg (20.3 mol)
of p-
CA 02485545 2004-11-18
_19_
toluenesulpphonic acid monohydrate in 17 L of water is added to the filtrate.
Another 20
L of water are added. The pH is adjusted to 8.0 with sodium hydroxide solution
(50%).
The remaining ethanol is distilled off under reduced pressure. Towards the end
of the
distillation the product crystallises out. The pH is adjusted to 7.5 with
sodium hydroxide
solution (50%) and the suspension formed is cooled to 3°C. The product
is centrifuged
off and washed with 13 L of water. The product is dried in the drying cupboard
at 50°C.
4.89 kg (69% of theory) of the title compound are obtained in the form of the
crude
product.
Further auriflcation of the p-toluenesulphonic acid salt:
4.75 kg of the crude product are suspended in 38 L of water. The suspension is
stirred
for 2.5 hours at 20°C. The suspension is centrifuged off and washed
with 19 L of water.
The product is dried at 50°C in the drying cupboard.
3.86 kg (81% of theory) of the title compound are obtained.
1 S HPLC: Rf = 3.6 min (p- toluenesulphonic acid)
Rf= 17.6 min (product)
Column: Inertsil ODS-2, 5 pm, 125x4.6 mm; solvent A: 0.3% aqueous KH2P04
solution,
adjusted to pH = 5.0 with 1 M NaOH; solvent B: acetonitrile; column
temperature: 45°C;
flow: 1 mL/min; gradient system: start: 10% solvent B; within 20 min gradient
to 25%
solvent B, within 10 min gradient to 50% solvent B; concentration of the
sample
solution: 2 mg/mL in acetonitrile/water = 7:3; injection volume: 3 uL;
detection at 217
nm.
CA 02485545 2004-11-18
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Example 6: Method of preparing the free base by ester cleaving with potassium
hydroxide starting from the p-toluenesulphonic acid salt of the ethyl ester
(R)-2-(4-Amidinophenylaminomethyl)-1-methyl-5-[ 1-(carboxymethylamino)-1-
(pyrroli-
dinocarbonyl)-ethyl]-benzimidazole
3.7 kg (5.49 mol) of (R)-2-(4-amidinophenylaminomethyl)-1-methyl-5-[1-
(ethyloxycarbonylmethylamino)-1-(pyrrolidinocarbonyl)-ethyl]-benzimidazol-p-
toluenesulphonic acid salt are dissolved in 7.4 L of methanol at 40°C.
To this solution is
added a solution of 0.795 kg (12.8 mol) of potassium hydroxide powder in 5.6 L
of
methanol and this is then rinsed with 1.8 L of methanol. The mixture is
stirred for 2.5
hours at 40°C. The potassium salt of the p-toluenesulphonic acid
crystallises out. A
solution of 1.37 kg (7.2 mol) of p-toluenesulphonic acid monohydrate in 2.8 L
of
methanol is added to the suspension, this is rinsed with 1.8 litres of
methanol and
cooled to 22°C. The precipitated potassium salt of p-toluenesulphonic
acid is separated
off using a pressure filter and the filter cake is washed with 7.4 litres of
methanol. The
filtrate is inoculated with the title compound and stirred overnight. The
precipitated
product is suction filtered under argon, washed with 3.7 L of methanol and
recycled into
the reactor while still damp. 18.5 L of methanol are added and the suspension
is
refluxed for one hour and cooled to 22°C. The product is suction
filtered under argon,
washed with 3.7 L of methanol and dried at 30°C in a circulating air
drier.
2.22 kg (85% of theory) of the title compound are obtained.
Melting point: Tm.P. = 241 °C ~ 5°C (decomposition, DSC,
evaluated using onset,
heating rate: 10°C/min, measured with DSC 204 of Messrs
Netzsch-Geratebau GmbH)
Example 7: Method of precipitating the monohydrochloride from ethanol
(R)-2-(4-Amidinophenylaminomethyl)-1-methyl-5-[1-(carboxymethylamino)-1-
(pyrroli-
dinocarbonyl)-ethyl]-benzimidazole-monohydrochloride
5.0 g of (R)-2-(4-amidinophenylaminomethyl)-1-methyl-5-[1-(carboxymethylamino)-
1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole are refluxed in 25 mL of ethanol.
After the
addition of 2 mL of water a solution is obtained. The solution is filtered
clear and the
CA 02485545 2004-11-18
-21 -
filter is rinsed with 25 mL of ethanol. The filtrate is heated to 70°C.
A solution of 0.802
mL of cons. hydrochloric acid in 25 mL of ethanol is added and then another 25
mL of
ethanol are added. The mixture is cooled to 25°C and stirred for one
hour at this
temperature. The product is filtered off, washed with 15 mL of ethanol and
dried in the
circulating air drier.
4.95 g (92% of theory) of the title compound are obtained as a crystalline
solid
Melting point: Tm,p. = 220°C ~ 5°C (decomposition, DSC,
evaluating using onset,
heating rate: 10°Clmin )
CA 02485545 2004-11-18
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Brief description of the Figures
Figure 1 shows the x-ray powder diffractogram of the crystalline
monohydrochloride of
the compound (R)-2-(4-amidinophenylaminomethyl)-1-methyl-5-[1-
(carboxymethylamino)-1-(pyrrolidinocarbonyl)-ethyl]-benzimidazole.
Figure 2 shows the x-ray powder diffractogram of the crystalline compound (R)-
2-(4-
amidinophenylaminomethyl)-1-methyl-5-[1-(carboxymethylamino)-1-(pyrrolidino-
carbonyl)-ethyl]-benzimidazole.
