Note: Descriptions are shown in the official language in which they were submitted.
CA 02284710 1999-09-23
WO 98/42673 PCTIEP98/OI740
1
QUINOLINE-2-CARBOXYLIC ACID DERIVATIVE AND ITS USE AS EXCITATORY AMINO ACIDS
ANTAGONIST
This invention relates to an enantiomer of (~) E 4-(4-Acetylamino-
, phenylcarbamoylmethylene}-5,7-dichloro-1,2,3,4-tetrahydro quinoline 2-
carboxylic acid a potent and specific antagonist of excitatory amino
acids, to processes for preparing the same, to pharmaceutical
compositions containing it, to its use in medicine.
WO 97112870 describes inter alia (~) E 4-(4-Acetylamino
phenylcarbamoylmethylene)-5,7-dichloro-1,2,3,4-tetrahydro quinoline
2-carboxylic acid (A)
O
c l \ ~ ,~\ / j _. _
--NHCOCH3
CI' ~ - N ,. _ COZH
H
(A)
and salts thereof, which have an antagonist action at the strychnine
insensitive glycine binding site located on the N-methyl-D- aspartate
(NMDA) receptor complex.
We have now found that an enantiomer of compound (A) herein after
referred to as the (+) enantiomer exhibits a particular useful profile of
activity as a selective antagonist for the strychnine insensitive glycine
binding site on the NMDA receptor complex.
The present invention thus provides the (+) enantiomer of (E) 4-(4-
acetylamino-phenylcarbamoylmethylene)-5,7-dichloro-1,2,3,4-tetrahydro
quinoline 2-carboxylic acid (hereinafter compound (I)) and salts thereof,
substantially free of the corresponding (-) enantiomer.
CA 02284710 1999-09-23
WO 98/42673 PCT/EP98101700
2
The term substantially free as used herein means that compound (I)
contains less than 10% of the {-) enantiomer and preferably less than
5%.
The term (+) enantiomer as used herein refers to the specific
enantiomer which is the product of examples 2, 4 and 5.
For use in medicine the salts of compound (I) will be physiologically
acceptable thereof. Other salts however may be useful in the
preparation of compound I or physiologically acceptable salts thereof.
Therefore, unless otherwise stated, references to salts include both
physiologically acceptable salts and non-physiologically acceptable salts
of compound (I).
Suitable physiologically acceptable salts of compounds of the invention
include base addition salts.
Suitable physiologically acceptable base addition salts of compound (I)
include alkali metal or alkaline earth metal salts such as sodium,
potassium, calcium, and magnesium, and ammonium salts, formed with
amino acids (e.g. lysine and arginine) and organic bases ( e.g. procaine,
phenylbenzylamine, ethanolamine diethanolamine and N-methyl
glucosamine).
A preferred salt of compound (I} is the sodium salt.
The compound of the invention and/or physiologically acceptable salts
thereof are excitatory amino acid antagonists. More particularly they are
potent antagonists at the strychnine insensitive glycine binding site
associated with the NMDA receptor complex. As such it is a potent
antagonist of the NMDA receptor complex. Compound (I) is therefore
useful in the treatment or prevention of neurotoxic damage or
neurodegenerative diseases. Thus compound (I) is also useful for the
treatment of neurotoxic injury which follows cerebral stroke,
thromboembolic stroke, haemorrhagic stroke, cerebral ischemia,
cerebral vasospam, hypoglycemia, amnesia, hypoxia, anoxia, perinatal
asphyxia cardiac arrest. Compound I is also useful in the treatment of
CA 02284710 1999-09-23
WO 98/42673 PCT/EP98101700
3
chronic neurodegenerative diseases such as Huntingdon's disease,
Alzheimer's senile dementia, amyotrophic lateral sclerosis, Giutcrric
Acidaemia type, multi-infarct dementia, status epilecticus, contusive
injuries (e.g. spinal cord injury and head injury), viral infection induced
neurodegeration (e.g. AIDS, encephalopaties}, Down syndrome,
epilepsy, schizophrenia, depression, anxiety, pain, neurogenic bladder,
irritative bladder disturbances, migraine, headaches, including cluster
headaches, tension headache, drug dependency, including withdrawal
symptoms from alcohol, cocaine, opiates, nicotine, benzodiazepine and
emesis.
The potent and selective action of the compound of the invention at the
strychnine- insensitive glycine binding site present on the NMDA
receptor complex may be readily determined using conventional test
procedures. Thus the ability to bind at the strychnine insensitive glycine
binding site was determined using the procedure of Kishimoto H et al. J
Neurochem 1981, 37 1015-1024. The selectivity of the action of
compound (I) for the strychnine insensitive glycine site was confirmed in
studies at other ionotropic known excitatory amino acid receptors. Thus
compound {I) was found to show little or no affinity for the kainic acid
(kainate) receptor, a-amino-3-hydroxy-5-methyl-4-isoxazole-proprionic
acid (AMPA) receptor or at the NMDA binding site.
The compound of the invention has also been found to inhibit NMDA
induced convulsions in mice using the procedure Chiamulera C. et al.
Psychopharmacology (1990) 102, 551-552.
The neuroprotective activity of the compound of the invention was
demonstrated in the middle cerebral artery occlusion preparation in
mice, using the procedure described by Chiamulera C. et al., European
Journal of Pharmacology, 216 (1992) pp. 335-336.
The invention therefore provides for the use of compound (I) and/or
physiologically acceptable salt thereof for use in therapy and in
CA 02284710 1999-09-23
WO 98/42673 PCT/)JP98/01700
4
particular use as medicine for antagonising the effects of excitatory
amino acids upon the NMDA receptor complex.
The invention also provides for the use of compound (I) and/or a
physiologically acceptable salt thereof for the manufacture of a
medicament for antagonising the effects of excitatory amino acids upon
the NMDA receptor complex.
According to a further aspect, the invention also provides for a method
for antagonising the effects of excitatory amino acids upon the NMDA
receptor complex, comprising administering to a patient in need thereof
an antagonistic amount of compound (I) and/or a physiologically
acceptable salt.
It will be appreciated by those skilled in the art that reference herein to
treatment extends to prophylaxis as well as the treatment of established
diseases or symptoms.
It will further be appreciated that the amount of the compound of the
invention required for use in treatment will vary with the nature of the
condition being treated, the route of administration and the age and the
condition of the patient and will be ultimately at the discretion of the
attendant physician. In general however doses employed for adult
human treatment will typically be in the range of 2 to 800mg per day,
dependent upon the route of administration.
Thus for parenteral administration a daily dose will typically be in the
range 20-800mg, preferably 60-800mg per day. For oral administration
a daily dose will typically be within the range 200-800mg, e.g. 400-
600mg per day.
The desired dose may conveniently be presented in a single dose or as
divided doses administered at appropriate intervals, for example as two,
three, four or more sub-doses per day.
,.
CA 02284710 1999-09-23
WO 98/42673 PCT/EP98/01700
While it is possible that, for use in therapy, compound (I) may be
administered as the raw chemical, it is preferable to present the active
ingredient as a pharmaceutical formulation.
5 The invention thus further provides a pharmaceutical formulation
comprising compound (I) or a physiologically acceptable salt thereof
together with one or more pharmaceutically acceptable carriers thereof
and, optionally, other therapeutic andlor prophylactic ingredients. The
carriers) must be 'acceptable' in the sense of being compatible with the
other ingredients of the formulation and not deleterious to the recipient
thereof.
The compositions of the invention include those in a form especially
formulated for oral, buccal, parenteral, inhalation or insufflation, implant,
or rectal administration. Parenteral administration is preferred.
Tablets and capsules for oral administration may contain conventional
excipients such as binding agents, for example, syrup, acacia, gelatine,
sorbitol, tragacanth, mucilage of starch or polyvinylpyrrolidone; fillers, for
example, lactose, sugar, microcrystalline cellulose, maize-starch,
calcium phosphate or sorbitol; lubricants, for example, magnesium
stearate, stearic acid, talc, polyethylene glycol or silica; disintegrants,
for
example, potato starch or sodium starch glycoiiate, or wetting agents
such as sodium lauryl sulphate. The tablets may be coated according to
methods well known in the art. Oral liquid preparations may be in the
form of, for example, aqueous or oily suspensions, solutions emulsions,
syrups or elixirs, or may be presented as a dry product for constitution
with water or other suitable vehicle before use. Such liquid preparations
may contain conventional additives such as suspending agents, for
example, sorbitol syrup, methyl cellulose, glucoselsugar syrup, gelatin,
hydroxyethylcellulose, carboxymethyl cellulose, aluminium stearate get
or hydrogenated edible fats; emulsifying agents, for example, lecithin,
sorbitan mono-oleate or acacia; non-aqueous vehicles (which may
include edible oils), for example, atmond oil, fractionated coconut oil, oily
esters, propylene glycol or ethyl alcohol; solubilizers such as surfactants
CA 02284710 1999-09-23
WO 98/42673 PCT/EP98/01700
6
for example polysorbates or other agents such as cyclodextrins; and
preservatives, for example, methyl or propyl p- hydroxybenzoates or
ascorbic acid. The compositions may also be formulated as
suppositories, e.g. containing conventional suppository bases such as
cocoa butter or other glycerides.
For buccal administration the composition may take the form of tablets
or lozenges formulated in conventional manner.
The composition according to the invention may be formulated for
parenteral administration by injection or continuous infusion.
Formulations for injection may be presented in unit dose form in
ampoules, or in multi-dose containers with an added preservative. The
compositions may take such forms as suspensions, solutions, or
emulsions in oily or aqueous vehicles, and may contain formulatory
agents such as suspending, stabilising and/or dispersing agents.
Alternatively the active ingredient may be in powder form for constitution
with a suitable vehicle, e.g. sterile, pyrogen-free water, before use.
For administration by inhalation compound (I) according to the invention
is conveniently delivered in the form of an aerosol spray presentation
from pressurised packs, with the use of a suitable propellant, such as
dichlorodifluoromethane, tirchlorofluoromethane, dichloro-
tetrafluoroethane, carbon dioxide or other suitable propellants, such as
dichlorodifluoromethane, trichlorofluoromethane, dichloro-
tetrafluoroethane, carbon dioxide or other suitable gases, or from a
nebuliser. In the case of a pressurised aerosol the dosage unit may be
determined by providing a valve to deliver a metered amount.
Alternatively, for administration by inhalation or insufflation, the
compounds according to the invention may take the form of a dry
powder composition, for example a powder mix of the compound and a
suitable carrier such as lactose or starch. The powder composition may
be presented in unit dosage form in, for example, capsules or cartridges
CA 02284710 1999-09-23
WO 98/42b73 PCT/BP98/01700
7
of e.g. gelatin, or blister packs from which the powder may be
administered with the aid of an inhaler or insufflator.
The composition according to the invention may also be formulated as a
depot preparation. Such long acting formulations may be administered
by implantation (for example subcutaneously or intramuscularly) or by
intramuscular injection. Thus for example, the compounds of the
invention may be formulated with suitable polymeric or hydrophobic
materials (for example as an emulsion in an acceptable oil) or ion
exchange resins, or as sparingly soluble derivatives, for example, as a
sparingly soluble salt.
The compositions according to the invention may contain between 0.1 -
99% of the active ingredient, conveniently from 30- 95% for tablets and
capsules and 3-50% for liquid preparations.
In a further aspect the invention provides processes for the preparation
of compound 1.
Thus in a first process (hereinafter Process A) compound (I) ((+)-E-4-(4-
Acetylamino-phenylcarbamoylmethylene)-5,7- dichloro-1,2,3,4-tetra-
hydroquinoline-2-carboxylic acid) may be prepared by esterification of
compound A with a suitable chiral alcohol, separating the resultant
diastereomeric esters by conventional means e.g. chromatography or
crystallisation followed by hydrolysis of the required single
diastereomeric ester.
Suitable chiral alcohols for use in the process A include (+)S-indanol,
(+)S-methyl mandelate, chiral (C1-4)alkyl lactate: i.e., (+)R or (-)S
methly lactate, (+)R t-butyl lactate, (+)R or (-)S ethyl lactate, (-)S
isopropyl lactate, (-)S butyl lactate, (+)R isobutyl lactate or chiral aralkyl
lactate (i.e. benzyl lactate), (-)S perillyl alcohol, (-)methyl(R)-3-hydroxy-
2-methylpropionate, (-)(R)-2-butanol, (-)(S)-2-methyl-1-butanol.
CA 02284710 1999-09-23
WO 98/42673 PCT/EP98/01700
8
The diastereomeric esters of compound A including the single
diastereomeric ester substantially free of the other diastereomeric are
novel compounds and represent a further aspect of the invention
The diastereomeric esters of compound A may be prepared by
conventional means such as reaction of the chiral alcohol with an
activated derivative of the compound A in an aprotic solvent such as
ether e.g. tetrahydrofuran. The activated derivative of Compound A
may be prepared from compound A using conventional means for
preparing activated derivatives of a carboxylic acid groups such as
those conveniently used in peptide synthesis.
A particularly convenient method of preparing the diastereomeric esters
of compound A is to prepare the activated derivative of compound A in
the presence of the chiral alcohol.
Thus for example compound A may be treated with the Mitsunobu
combination of reagents, i.e. a dialkyl azo-dicarboxylate such as
diethylazodicarboxylate and a triarylphosphine e.g. triphenylphosphine
or trialkylphoshine (i.e. tributylphosphine) in the presence of the chiral
alcohol.
The reaction conveniently takes place in the presence of a suitable
solvent such as an ether (e.g. diethylether or tetrahydrofuran), a
halohydrocarbon (e.g. dichloromethane) or a nitrite (e.g. acetonitrile) or
a mixture thereof at a temperature ranging from 0-30°.
The required single diastereomeric ester of compound A substantially
free of the other diastereomers may be obtained from the mixture
thereof by conventional means, for example by the use of conventional
chromatographic procedures such as preparative HPLC or by fractional
crystallization.
Compound (I) may be prepared from the corresponding single
diastereomeric ester of compound A by hydrolysis e.g. alkaline
rt_ _ , , ..
CA 02284710 1999-09-23
WO 98142673 PCT/EP98/01700
9
hydrolysis. Thus for example the hydrolysis may be carried using an
alkali metal hydroxide e.g. sodium hydroxide or lithium hydroxide in a
solvent such as an ether e.g. tetrahydrofuran and water.
Compound (I) may be isolated as the free acid or as a salt thereof.
Compound I may also be obtained from racemic compound A by use of
chiral HPLC procedures.
Compound {A) may be prepared by reaction of an activated derivative of
the carboxylic acid (II) in which R1 is a carboxylic acid protecting group
and R3 is hydrogen or a nitrogen protecting group
C02H
CI
~__
CI ~ N ' '-COzR~
R3
with the amine(III)
NHCOCH3
NH2
followed where necessary by subsequent removal of the carboxylic acid
protecting group R~ and any nitrogen protecting group R3 using the
methods and examples described in W097I12870.
The invention also provides a further process for the preparation of the
compound (I) (hereinafter process B) which comprises reacting an
activated derivative of the carboxylic acid (IV)) in which R3 is hydrogen
or a nitrogen protecting group and R5 is a suitable chiral group with the
amine (III).
CA 02284710 1999-09-23
WO 98142673 PCT/EP98/01700
C02H
CI
l
f
CI N COZRS
R3
(IV)
5
NHCOCH3
1\~1
NHz
10 and subjecting the resulting compound to the following reactions:
i) where necessary removal of nitrogen protecting group R3
ii) separation of the resultant diastereomeric esters
iii) hydrolysis of the required single diastereomeric ester and isolation of
the (+) enantiomer as a free acid or a salt thereof, and if desired the
subsequent conversion of the free acid of the (+) enantiomer into a salt
thereof.
Suitable chiral groups (R5) for use in the process B are those derived
from chiral alcohols such as (+)S-indanol, (+}S-methyl mandelate, chiral
(C1-4)alkyl lactate: i.e., (+)R or (-)S methly lactate, (+)R t-butyl lactate,
(+)R or (-)S ethyl lactate, (-)S isopropyl lactate, (-)S butyl lactate, (+)R
isobutyl lactate or chiral aralkyl lactate (i.e. benzyl lactate), (-)S
perillyl
alcohol, (-)methyl(R}-3-hydroxy-2-methylpropionate, (-)(R)-2-butanol, (-)
(S)-2-methyl-1-butanol.
R5 is preferably a group derived from a chiral (C1-4)alkyl lactate alcohol.
CA 02284710 1999-09-23
WO 98142673 PCT/EP98/01700
11
More preferably R5 is derived from (+)(R) t-butyl lactate alcohol.
Suitable activated derivatives of the carboxylic acid group include the
corresponding acyl halide, mixed anhydride, activated ester such as a
thioester or the derivative formed between the carboxylic acid group and
a coupling agent, such as that used in peptide chemistry, for example
carbonyl diimidazole or a diimide, such as dicyclohexylcarbodiimide.
The reaction is preferably carried out in an aprotic solvent, such as a
hydrocarbon, a halohydrocarbon such as dichloromethane or an ether
such as tetrahydrofuran.
When R3 is a nitrogen protecting group, examples of suitable groups
include alkoxycarbonyl, e.g. t-butoxycarbonyl, arylsulphonyl e.g.
phenysulphonyl or 2-trimethylsilylethoxymethyl.
Alkyl when used as substituent or a part of a substituent group means
that the group may be straight or branched. Thus C1-4 alkyl includes
methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or ter-butyl.
The activated derivatives of the carboxylic acid (IV) may be prepared by
conventional means. A particularly suitable activated derivative for use
in this reaction is thioester such as that derived from pyridine-2-thiol.
These esters may conveniently be prepared by treating the carboxylic
acid (II) with 2,2'-dithiopyridine and triphenylphosphine in a suitable
aprotic solvent such as an ether e.g. tetrahydrofuran, a halohydrocarbon
e.g. dichloromethane, an amide e.g. N,N-dimethylformamide or
acetonitrile.
The appropriate diastereomeric derivative can be isolated by
conventional means e.g. chromatography or by crystallisation.
The hydrolysis step conveniently takes place using an alkali metal
hydroxide e.g. sodium hydroxide or lithium hydroxide in a suitable
solvent such as an ether i.e. tetrahydrofuran, water and a mixture
CA 02284710 1999-09-23
WO 98/42673 PCT/EP98/01700
12
thereof or alkali trialkylmethylsilanolate (e.g. trimethylsilanolate)
followed, where desired or necessary, by the addition of a suitable acid
e.g. hydrochloric acid to give the corresponding free carboxylic acid.
Compounds of formula (IV) or (II) may be prepared by the cyclisation of
a compound of formula (V}
COZR4
CI
i Rz
1 ~~~ ' ~
CI N ; C02R6
R3
(V)
in which R2 represents a bromine or iodine atom, R3 represents
hydrogen or a nitrogen protecting group, R4 represents a hydrogen atom
or a suitable carboxylic acid protecting group such as t-butyl group and
R6 represents R~ or R5 as defined in formula (II} or formula (IV)
respectively, followed by removal of the of carboxylic protecting group
R4 using conventional methods.
In one embodiment of this process the reaction may be carried out
using a catalytic amount of a Palladium (O} complex such as
tetrakis(triphenylphosphine)palladium and a suitable organic base such
as trialkylamine e.g. triethyfamine or inorganic base, e.g. potassium
carbonate.
The reaction is conveniently carried out in an aprotic solvent such as
acetonitrile or dimethylformamide at a temperature with the range of
20°C to 150°C followed, where necessary or desired, by
subsequent
removal of the carboxylic acid protecting group R4 and any protecting
group R3.
In a further embodiment of the process the reaction is carried out using
a catalytic amount of a Pd(II) salt such as palladium acetate, in the
presence of a suitable organic base such as trialkyl amine e.g.
triethylamine and of a triarylphosphine such as triphenylphosphine.
,,
CA 02284710 1999-09-23
WO 98/42673 PCT/EP98/01700
13
The reaction is carried out in an aprotic solvent such as acetonitrile or
dimethylformamide and preferably with heating, followed, where
necessary or desired, by subsequent removal of the carboxylic acid
protecting group R4 and any nitrogen protecting group R3.
Compounds of formula (V) may be prepared by reacting a imino ester of
formula(VI), wherein R2 and Rs have the meanings defined above, with
a compound of formula (VII) in which R~ represents a C1-4. alkyl group
and R4 is a hydrocarbysilyl group such as trialkylsilyl, e.g. trimethylsilyl
or terbutyldimethylsilyl or a suitable carboxylic acid protecting group
such as tent-butyl group, followed, if desired, by the conversion of the
group NH into a nitrogen protecting group NR3.
cl
1 . RZ
oslR,
o
CI' .. ~ .- i ~ Rs
0 , \ oR4
(VI)
(VII)
The reaction is carried out in an aprotic solvent such as
halohydrocarbon e.g. dichloromethane, chlorobenzene or acetonitrile at
low temperature e.g. -78°C in the presence of a Lewis acid such as zinc
bromide and zinc chloride.
The conversion of the group NH into the nitrogen protected group NR3
may be obtained using conventional means for introducing such
nitrogen protecting groups, e.g. reaction with the group R3X wherein X is
a leaving group e.g. halogen or methanesuiphonate.
The process for preparing compounds of formulae (II) or (IV), using the
intermediate (V) when prepared from intermediates (VI) and (VII), is
novel and forms a further feature of the invention.
CA 02284710 1999-09-23
WO 98/42673 PCTIEP98/01700
14
A particularly preferred embodiment of this novel process for preparing
compounds of formula (V) is to use an intermediate ester (Vi), wherein
R6 group is derived from (+)R t-butyl lactate alcohol. This yields a
mixture of diastereomeric esters in which the required diastereomeric
ester is obtained in diastereomeric excess.
Further, the cyclisation of the compound (V) so obtained using the
process conditions described above affords the required compound (IV)
as a mixture of diastereomeric esters in which the required
diastereomeric ester is also obtained in diastereomeric excess.
Compounds of formula (VI) may be prepared by reaction of amine (IX)
with a compound of formula (VIII) wherein R2, R6 have the meanings
defined for compounds of formula (V).
CI
J. RZ
CI ~ ~ ~-'~ ~ NHz (IX)
OH
-O~R
OH s
(VIII)
The reaction is preferably carried out in a solvent such as an aromatic
hydrocarbon (e.g. benzene toluene or xylene) at a temperature ranging
from ambient to the reflux temperature of the reaction mixture.
Compounds of formula (III), (VII), (VIII), and (IX) are either known
compounds or may be prepared by analogous methods to those used
for known compounds.
Thus compounds of formula (VII) may be prepared according to
procedures described in Tetrahedron Letters, Vol. 22, No. 29, pp. 2833 -
r
CA 02284710 1999-09-23
WO 98/42673 PCT/EP98/01700
2836, 1981. Compounds of formula (VIII) may be prepared according to
procedures described in Helvetica Chimica Acta, 1981 Vol. 64, p. 2808 .
In any of the above reactions the carboxylic acids protecting group may
5 be removed by conventional procedures known for removing such
groups. Thus compounds where R1 is a benzyl group, this may be
removed by hydrolysis using an alkali metal hydroxide e.g. lithium
hydroxide or sodium hydroxide in a suitable solvent such as ethanol or
isopropanol, water or mixtures thereof, followed, where desired or
10 necessary, by that addition of a suitable acid e.g. hydrochloric acid to
give the corresponding tree carboxylic acid.
When R4 is a t butyl group this may be removed by hydrolysis using
organic acids e.g. formic acid.
15 In any of the above reactions the nitrogen protecting group may be
removed by conventional procedures known for removing such groups,
for example by acid or base hydrolysis. Thus when R3 is alkoxycarbonyl
e.g. t-butoxycarbonyl or phenylsulphonyl it may be removed by alkaiine
hydrolysis using for example lithium hydroxide in a suitable solvent such
as tetrahydrofuran or an alkanol e.g. isopropanol. Alternatively the
alkoxycarbonyl group may be removed by acid hydrolysis.
Physiologically acceptable salts of compound f may be prepared by
treating the corresponding acid with an appropriate base in a suitable
solvent. For example alkali and alkaline metal salts may be prepared
from an alkali or alkaline metal hydroxide, or the corresponding
carbonate, bicarbonate or trialkylsilanolate e.g. trimethylsilanolate
thereof.
Alternatively alkali or alkaline earth salts may be prepared by direct
hydrolysis of carboxylic acid protected derivatives of compound I with
the appropriate alkali or alkaline metal hydroxide.
In order that the invention may be more fully understood the following
examples are given by way of illustration only.
CA 02284710 1999-09-23
WO 98/42673 PCT/EP98/01700
16
In the Intermediates and Examples unless otherwise stated:
Melting points (m.p.) were determined on a Gallenkamp m.p. apparatus
and are uncorrected. All temperatures refers to OC. Infrared spectra
were measured on a FT-IR instrument. Proton Magnetic Resonance
(1 H-NMR) spectra were recorded at 400 MHz, chemical shifts are
reported in ppm downfield (d) from Me4Si, used as internal standard ,
and are assigned as singlets (s), doublets (d), doublets of doublets (dd),
triplets (t), quartets (q) or multiplets (m). Column chromathography was
carrier out over silica gel (Merck AG Darmstaadt, Germany). The
following abbreviations are used in text: EA = ethyl acetate, CH =
cyclohexane, DCM = dichloromethane, THF = tetrahydrofuran, TFA =
trifluoroacetic acid, TEA = triethylamine, DMSO = dimethylsulphoxide,
Tlc refers to thin layer chromatography on silica plates. Solution were
dried over anhydrous sodium sulphate; r.t. (RT) refers to room
temperature.
Intermediate 1
-tert-butyl-(R)-acrytoyloxy-2-methylacetate
To a solution of (R)-tent butyl lactate alcohol (4.5 g), triethylamine (9.5
ml) and dimethylaminopyridine ( 0.73 g) in dry dichioromethane (200m1)
was added, at 0°C, a solution of acryfoyl chloride (5.5 ml) in
dichloromethane (100 ml), and the resulting mixture was stirred for 1 hr
at 0°C and for an additional hour at room temperature. Then a 1 M
solution of HCI was added followed by ethyl acetate (600 ml). The
organic phase was washed with water and brine. Final purifccation by
column chromatography (cyclohexanelethyl acetate 85115) afforded the
title compound (4.6g) as a colourless oil.
' H NMR (DMSO) (ppm) 6.36 (dd, 1 H), 6.22 (dd, 1 H), 5.99 (dd, 1 H),
4.89 (q, 1 H), 1.40 (d, 3H), 1.39 (s, 9H)
1R (CDC13) (cm-') 1727
Intermediate 2
CA 02284710 1999-09-23
WO 98/42673 PCT/EP98/01700
17
1-tert-butyl-(R)-2(oxoacetoxy)-2-methyl acetate
A solution of intermediate 1 (4.6 g} in THF/H20 (3/1) (28 ml) was
reacted overnight at room temperature with osmium tetroxide (4% wt in
water, 5 ml) and sodium periodate (12.3 g}. The mixture was taken up
with ether (500 ml), the water phase was separated, and the organic
phase was dried and concentrated. Final purification by column
chromatography (cyclohexane/ethyl acetate 60140) afforded the title
compound (4.1g) as a colourless oil.
' H NMR (DMSO): 6.75 (d, 1 H); 6.70 (d, 1 H); 5.05 (t, 1 H); NMR - 4.85m
(1 H);1.40m(12H).
Intermediate 3
(3,5-dichloro-iodophenylimino)acetic acid, 1-(R)-(1 tert
butoxycarbonyl)ethyl ester
A solution of intermediate 2 (0.784 g) in toluene (20 ml) was refluxed in
Dean-Stark apparatus for 1 hr. Then, 3,5-chloro-2-iodoaniline (0.75 g)
and MgS04 (5 g) was added, and the mixture refluxed for 1 hr. Then
mixture was cooled, filtered through celite to eliminate the MgS04,
concentrated to give the title compound (1.2 g) as a pale yellow oil.
' H NMR (DMSO) (ppm) 7.95 (s, 1 H); 7.67 (d, 1 H); 7.30 (d, 1 H); 5.09 (q,
1 H); 1.49 (d, 3H); 1.43 (s, 9H)
IR (Film} (crri'} 1743
Intermediate 4
(E)-5-(3,5-dichloro-iodophenylimino)hex-2-enedioic acid, 6-[1-(R) (1
tert-butoxycarbonyl)]-ethyl ester
To a suspension of ZnCl2 (0.36g) in dry dichloromethane (10m1) cooled
to -78°C, a solution of intermediate 3 (1.2g) in dry dichloromethane
(20m1) was added. Then 1,1 trimethylsilyloxy 1,3 butadiene (1.14g) was
added and the resulting mixture was stirred for 2hrs at -30°C. Then a
saturated solution of NH4CI (20m1) was added followed by ethyl acetate
(30m1). The organic phase was washed with brine (20m1) and dried.
Purification by column chromatography (cyclohexanelethyl acetate
50!50) afforded the title compound (1.13g) as a colourless oil
(diastereomeric excess 50%).
CA 02284710 1999-09-23
WO 98142673 PCT/EP98/01700
18
H NMR (DMSO) d (ppm) 12.3 (bs, 1 H) 7.01 (d, 1 H); 6.79 (m, 1 H); 6.66
(d, 1 H); 5.90 (d, 1 H); 5.29 (d, 1 H); 4.97 {q, 1 H); 4.72 {m, 1 H); 2.83 (m,
2H); 1.39 (m, 12H).
Intermediate 5
{E)-4-carboxymethylene-5,7-dichloro-1,2,3,4-tetrahydroquinoiine-2-
carboxylic acid, [1-(R)-(1-tert-butoxycarbonyl))ethyl ester
To a solution of intermediate 4 (1.2g) in dry DMF (10m1) was added TEA
(0.7m1) and Pd(PPh3)4 (0.248g). The reaction mixture was heated to
100°C for 1 hour, then ethyl acetate (20m1) was added followed by a 1 M
solution of HCI (10m1). The organic phase was washed with brine
(20m1), dried and concentrated. Final purification by column
chromatography (cyclohexanelethyl acetate 40/60) afforded the title
compound (0.5g) as a colourless oil (diastereomeric excess 50%).
' H NMR (DMSO) 12.3 (s, 1 H); 7.27 {bs, 1 H); 6.73 (d, 1 H); 6.45 (d, 1 H);
6.40 (s, 1 H); 4.79 (q, 1 H); 4.29 (m, 1 H); 3.61 (m, 1 H); 3.13 (m, 1 H);
1.35
(m, 10H).
Intermediate 6
(E)-4-j(2-pyridyl)thiocarbonylmethylene]-5,7-dichloro-1,2,3,4-
tetrahydroquinoline-2-carboxylic acid, [1-(R)-(1-tert-
butoxycarbonyl)]ethyl ester
To a solution of intermediate 5 (0.5g) in dry THF (30m1) was added
PySSPy (0.66g) and PPh3 (0.81g). The reaction mixture was stirred for
1 h at room temperature, then the solvent was evaporated and the crude
purified by column chromatography (cyclohexane/ethyl acetate 80/20) to
give the title product (0.170g) as a yellow foam (diastereomeric excess
60%).
~ H NMR (DMSO) p.p.m 8.61 (m, 1 H); 7.91 (m, 1 H); 7.71 (m, 1 H); 7.46
(bs, 1 H); 7.45 (m, 1 H); 6.88 (s, 1 H); 6.78 (d, 1 H); 6.76 (d, 1 H); 4.81
(q,
1 H); 4.36 (m, 1 H); 3.73 (dd, 1 H); 3.05 (m, 1 H); 1.4 (m, 3H); 1.34 (s, 9H).
Example 1
, ,
CA 02284710 1999-09-23
WO 98/42673 PCT/EP98/01700
19
(+I-)(E)-4-acetylamino-phenylcarbamoylmethylene)-5,7 dichloro
1,2,3,4-tetrahydro quinoline-2-carboxylic acid
(diastereomers 1a and 1b)
A solution of diethylazodicarboxylate (0.136m1;) in dry tetrahydrofuran
(10m1) was added, dropwise over 5 minutes, to a suspension of (~)(E}-
4-(4-acetylamino-phenylcarbamoylmethylene)-5,7-dichloro-1,2,3,4-
tetrahydroquinoline-2-carboxylic acid (270mg), triphenylphosphine
(228mg) and tert-butyl (R)-(+)-lactate (127mg) in dry tetrahydrofuran
(20m1) under a nitrogen atmosphere.
The yellow solution was stirred at 23°C for 30 minutes, then
concentrated in vacuo and purified by flash chromatography eluting with
cyclohexane/ethyl acetate 4:6 to give 240mg of the title compound (a
mixture of the two diastereoisomers 1a and 1b). The diastereomers
were separated by preparative HPLC (column:Supelcosil LC-CN; phase
hexane-tetrahydrofuran 65:35 and after 14 minutes 60:40; flux
10m1/min; 7~=260nm) and then further purified on silica, eluting with
cyclohexane/ethyl acetate, first 8:2 then 1:1, to give diastereoisomer 1a
:91 mg as whitish solid, and diastereoisomer 1 b 76mg as yellow solid
Example 1: rn.p.175-177°C. IR (nujol): 3200 (NH), 1738 (C=O) cm-'.'H-
NMR (DMSO): 10.09-10.05 (2s, 1 H); 9.86-9.84 (2s, 1 H); 7.64-7.44 (m,
4H); 7.34-7.19 (2d, 1 H); 6.73-6.66 (d, 2H); 6.71-6.64 (2s, 1 H); 4.76-4.56
(2q, 1 H); 4.39-4.26 and 3.73 (m and dd, respectively, 2H); 3.30-2.68
(dd, 1 H); 2.00 (s, 3H); 1.34-1.31 (2s, 9H); 1.29-1.15 (2d, 3H). MS:
m/z=562 [M+H]+
Diastereomer 1a m.p. 206-8°C. T.Lc.ethyl acetate-cyclohexane 7:3,
Rf=
047. IR (nujol): 3314 (NH), 1730, 1666, 1656 (C=O) cm-'. 'H-NMR
(DMSO): 10.09 (s, 1 H}; 9.86 (s, 1 H); 7.57 (d, 2H); 7.49 (d, 2H); 7.33 (d,
7 H); 6.71 (d, 2H); 6.67 (d, 1 H); 6.65 (m, 1 H); 4.57 (q, 1 H); 4.37 (m, 1
H);
4.29 (m, 1 H); 2.69 (m, 1 H); 2.00 (s, 3H); 1.35 (s, 9H); 1.16 (d, 3H). MS:
m/z=561[M]+, 562 [M+H]+. HPLC: retention time 12.56min
(column:Supelcosil LC-CN; phase hexane-tetrahydrofuran 70:30; flux
0.8mllmin; ~. =260nm)
Diastereomer 1 b: m.p. 105-7°C. T.Lc.ethyl acetate-cyclohexane 7:3,
Rf=
040. IR (nujol): 3310 (NH), 1738 and 1659 (C=O) cm-'. 'H-NMR
(DMSO): 10.05 (s, 1 H); 9.85 (s, 1 H); 7.55 (d, 2H); 7.47 (d, 2H); 7.19 (d,
CA 02284710 1999-09-23
WO 98/42673 PCT/EP98/01700
1 H); 6.74 (d, 1 H); 6.73 (d, 1 H); 6.72 (s, 1 H); 4.77 (q, 1 H); 4.29 (m, 1
H);
3.74 (dd, 1 H); 3.29 (m, 1 H); 2.00 (s, 3H); 1.32 (s, 9H); 1.29 (d, 3H). MS:
m/z=561[M]+, 562 [M+H]+. HPLC: retention time 15.60min
(column:Supelcosil LC-CN; phase hexane-tetrahydrofuran 70:30; flux
5 0.8m1/min; ~.=260nm)
Example 2
(+)-E-4-(4-Acetylamino-phenylcarbamoylmethylene)-5,7- dichloro-
1,2,3,4-tetrahydroquinoline-2-carboxylic acid
10 Lithium hydroxide monohydrate (12.84mg) was added to a solution of
diastereoisomer 1a {from Example 1 86mg) in tetrahydrofuran (5mi) and
water (2.5m1). The solution was stirred at 23°C for 30 minutes, then
concentrated in vacuo. The residue was diluted with further water {1 Oml)
and extracted with ethyl acetate (2X15m1). The aqueous layer was
15 acidified with 5% hydrochloric acid until pH=1 and e5ctracted with ethyl
acetate (3X15m1). The combined organic extracts were dried and
concentrated in vacuo to give the title compound as a whitish solid
(56mg). m.p. 224-6°. IR (nujol): 3356-3302 {NH), 3350-2600 (OH); 1724
and 1663-1650 (C=O) cm-'. 'H-NMR (DMSO}: 12.71 (s, 1H); 10.10 (s,
20 1 H); 9.87 (s, 1 H); 7.56 (d, 2H}; 7.50 (d, 2H); 7.10 (d, 1 H); 6.70 (d,
2H);
6.68 (m, 1 H}; 4.11 (m, 1 H); 3.87 (m, 1 H); 3.08 (dd, 1 H); 2.01 (s, 3H).
MS: m/z=434 [M+H]+.
HPLC: retention time 15.2 min (cofumn:cyclobond z 2000 SN ; phase [i
cyclodextrin S Naphthyl ethyl carbamate, phase mobile: methanol buffer
ammonium acetate (pH=3); flux 1 mi/min. ; ~,=260 nm)
[a]o=[+16]20~ ~.= 598nm, solvent :dimethyl sulphoxide.
Conc=0.26% w/v
Example 3
~-4-(4-acetylamino-phenylcarbamoylmethylene)-5,7-dichloro-
1,2,3,4-tetrahydroquinoline-2-carboxylicacid,(1-(R)-(1-tert-
butoxycarbonyl)]ethyl ester
To a solution of intermediate 6 (0.155g) in dry toluene (20m1) 4
aminoacetanalide (0.05g} was added. The resulting mixture was heated
at 100°C for 3hrs, then the solvent was evaporated and the crude
. T.. ~ .......
CA 02284710 1999-09-23
WO 98/42673 PCT/EP98/017U0
21
purified by column chromatography (cyclohexanelethyl acetate 50/50) to
give the title compound (0.05 g) as a yellow solid.
' H-NMR (DMSO) d 10.05 (bs, 1 H); 9.85 (bs, 1 H); 7.55 (d, 2H); 7.47 {d,
2H); 7.19 (dd, 1 H); 6.74 (d, 1 H); 6.73 (d, 1 H); 6.72 (s, 1 H); 4.77 (q, 1
H);
4.29 (m, 1 H); 3.74 (dd, 1 H); 3.29 (m, 1 H); 2.00 (s, 3H); 1.32 (s, 9H);
1.29 (d, 3H).
IR (nujol) (cm~') 3310, 1738, 1659.
Example 4
(+)(E).4-(4-acetylamino-phenylcarbamoylmethylene)-5,7-dichloro-
1,2,3,4-tetrahydroquinoline-2-carboxylic acid
To a solution of example 3 (0.021 g) in THFIH20 (311 ) LiOH (0.005g)
was added. After 15mins. the THF was evaporated and water (2ml) was
added. The solution was washed with ethylacetate (2x5m1), then a 1 M
solution of HCI was added and the resulting solution was extracted with
ethyl acetate (2x5m1) and evaporated to give the title compound as a
pale yellow solid (0.01g).
'H-NMR (DMSO) d 12.71 (s, 1 H); 10.10 (s, 1 H); (9.87 (s, 1 H}; 7.56 (d,
2H); 7.50 (d, 2H); 7.10 (d, 1 H); 6.70 (d, 2H); 6.68 (m, 1 H); 4.11 (m, 1 H);
3.87 (m, 1 H); 3.08 (dd, 1 H); 2.01 (s, 3H).
IR (nujol) (cm-1 ) 3356-3302, 1724, 1663-1650.
HPLC: retention time 9.7 min (column: cyclobond SN; phase (3-
cyclodextrin S Naphthyl carbamate, phase mobile: methanol buffer
ammonium acetate (pH=5); flux 1 mllmin. ; ~,=260 nm)
Example 5
+) 4-(4-Acetylamino-phenylcarbamoylmethylene)-5,7-dichloro
1,2,3,4-tetrahydroquinoline-2-carboxylic acid, sodium salt
Sodium trimethylsilanolate (7.74 mg) was added to a suspension of (+}
4-(4-acetylamino-phenylcarbamoylmethylene}-5,7-dichloro-1,2,3,4-
tetrahydroquinoline-2-carboxylic acid (30 mg) in dry tetrahydrofuran (3
ml) under a nitrogen atmosphere. The yellow suspension was stirred at
23°C for 1 hr, then it was concentrated in vacuo and the residue was
triturated with diethyl ether (5 ml). After filtration the title compound was
obtained (27 mg) as a yellow solid.
CA 02284710 1999-09-23
WO 98/42673 PCT/EP98/01700
22
M.p. 202-5 °C (dec).
IR (nujol): 3400-3000 (NH), 1650 (C=O) cm-~. 'H-NMR (DMSO): 11.71
(bs, 1 H); 9.26 (bs, 1 H}; 7.65 (d, 2H); 7.49 (d, 2H); 6.74 (d, 1 H}; 6.71
(bs,
1 H); 6.52 (s, 1 H); 6.50 (d, 1 H); 3.51 (m, 1 H); 3.29 (m, 1 H); 2.64 (m, 1
H);
2.01 (s, 3H). MS: m/z=456 [M+H]+, 478 [M+HJ +. HPLC: retention time
14.28 min.(column: cyclobond I 2000SN; phase b-cyclodextrin S
Naphtyl ethyl carbamate, phase mobile: methanol-buffer ammonium
acetate, flux 1 mllmin; ~,=260nm).
Pharmacy Example
Intravenous Infusion % wlv
Compound (I) 0.3 - 0.5
Polysorbate 80 1
tris(hydroxymethyl)aminomethane 0.54
Dextrose solution 5% wlv qs to volume
Compound (1) and Polysorbate were added to a solution of
tris(hydroxymethyl)aminomethane in a 5% aqueous dextrose solution
suitable for injection. The solution was filtered through a sterile 0.2
micron sterilising filter and filled in containers before being sterilised by
autoclaving.
The affinity of the compound of the invention for strychnine insensitive
glycine binding site located on the NMDA receptor complex was
determined using the procedure of Kishimoto H. et al ,!. Neurochem
1981, 37, 1015-1024. The pKi value obtained is 8.8.
