Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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MERCAPTOACYLAMINO ACIDS AS METALLO-BETA-LACTAMASE INHIBITORS
This invention relates to chemical compounds having metallo-~i-lactamase
inhibitory and antibacterial properties. The invention also relates to methods
for the
preparation of such compounds, to pharmaceutical compositions containing them,
and to
uses thereof.
Metallo-(3-lactamases confer resistance to the vast majority of (3-lactam
based
therapies, including carbapenems and jeopardise the future use of all such
agents. As a
result of the increased use of carbapenems and other ~3-lactam antibiotics the
clinical
climate is becoming more favourable for the survival of clinical strains which
produce
metallo-~3-lactamases, and metallo-~-lactamases have now been identified in
common
pathogens such as Bacteroides fragilis, Klebsiella, Pseudomonas aeracginosa
and Serratia
marcescens. Emerging knowledge emphasises that metallo-(3-lactamases have the
potential to present a crisis situation for antimicrobial chemotherapy.
W097/30027 (21 August 1997) and W098/17639 (30 April 1998) disclose
certain p-thiopropionyl amino acid derivatives and their use as (3 lactamase
inhibitors.
A novel series of amino acid derivatives have now been discovered, which
compounds have metallo-~i-lactamase inhibitory properties, and are useful for
the
treatment of infections in animals.
According to the present invention there is provided a compound of formula (I)
or a pharmaceutically acceptable salt, solvate or in vivo hydrolysable ester
thereof:
R4S-C(R~R6)-C(=CHR3)-CON(R~)-CH(R 1 )-C02R
(I)
wherein:
R is hydrogen, a salt forming cation or an in vivo hydrolysable ester-formin'
group;
R 1 is hydrogen, (C 1 _6)alkyl optionally substituted by up to three halogen
atoms
or by a mercapto, (C 1 _6)alkoxy, hydroxy, amino, nitro, carboxy, (C 1-6)
alkylcarbonyloxy, (Cl_6)alkoxycarbonyl, formyl or {C1-6) alkylcarbonyl group,
(C3_~)cycloalkyl, (C3_7)cycloalkyl(C~_6)alkyl. (C~_6)alkenyl, (C2_6)alkynyl,
aryl,
aryl(C 1 _6)afkyl, heterocyclyl or heterocyciyl(C 1 _6)alkyl or is selected
from
CA 02298682 2000-O1-28
WO 99/06365 PCT/EP98/04974
ring C- ring
A B
(a)
C
ring ring
A B
D
{b)
in which A is a monocyclic aryl or heteroaryl ring and B is a monocyclic aryl,
alicyclic or
heterocyclic ring, C and D are independently -Zp-(CRgR9)q- or -(CRgR9)q-
Zpwhere p is
0 or 1, q is 0 to 3 provided that p + q in C is not 0, Rg and R9 are
independently hydrogen
or (CI_6)alkyl or together represent oxo and Z is O, NRIO or S(O)x where RIp
is
hydrogen, (C 1_6)alkyl or aryl(C 1 _6)alkyl and x is 0-2, and wherein C and D
are linked
ortho to one another on each of rings A and B in formula (b);
R~ is hydrogen, (C1_6)alkyl or aryl(C1_6)alkyl;
R3 is hydrogen, (C1_6)alkyl optionally substituted by up to three halogen
atoms,
(C3_~)cycloalkyl, fused aryl(C3_~)cycloalkyl, (C3_~)cycloalkyl(C2_6)alkyl,
(C2_
~)alkenyl, (C2_6)alkynyl, aryl, aryl-(C 1 _6)aIkyl, heterocyclyl or
heterocyclyl-(C 1 _6)alkyl;
R4 is hydrogen, or an in vivo hydrolysable acyl group; and
R5 and R6 are independently hydrogen and (Cl_6)alkyl or together represent
(CH2)r where r is 2 to 5.
The compound of formula (I) may exist in a number of isomeric forms, all of
which, including E- and Z- geometric isomers and racemic and diastereoisomeric
forms,
are encompassed within the scope of the present invention.
It is preferred that the stereochemistry at the carbon atom marked * is D-,
particularly when R 1 is selected from phenyl, (a) or (b).
The term 'aryl' includes phenyl and naphthyl, each optionally substituted with
up
to five, preferably up to three, groups selected from halogen, mercapto, (C 1
_6)alkyl
optionally substituted by I-3 halo, phenyl, phenyl(C 1 _6)alkyl, phenyl(C 1
_6)alkoxy, (C 1 _
6)alkoxy optionally substituted by 1-3 halo, hydroxy(C 1_6)alkyl, mercapto(C 1
_6)alkyl,
hydroxy, CO~R~, N(R~)2 or CON(R~)2 where each R~ is independently hydrogen. (C
1 _
6) alkyl or (C 1 _6) alkanoyl, OCONH2, vitro, (C 1 _6) alkylcarbonyloxy, (C 1
_
6)alkoxycarbonyl(C 1 _6) alkyl, formyl and (C 1 _6) alkylcarbonyl groups.
Each alicyclic ring suitably has from 4 to 7, preferably 5 or 6, ring carbon
atoms.
*rB
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Alicyclic rings may be unsubstituted or substituted by, for example, up to
five,
preferably up to three, groups selected from those mentioned above for
substitution on
arv 1.
The terms'heterocyclyl' and'heterocyclic' as used herein include aromatic and
non-aromatic, single and fused, rings suitably containing up to four hetero-
atoms in each
ring selected from oxygen, nitrogen and sulphur, which rings may be
unsubstituted or
substituted by, for example, up to three groups selected from those mentioned
above for
substitution on aryl and, for non-aromatic heterocyclic rings, oxo groups.
Each
heterocyclic ring suitably has from 4 to 7, preferably 5 or 6, ring atoms. The
term
'heteroaryl' refers to heteroaromatic heterocyclic ring or ring system,
suitably having 5 or
6 ring atoms in each ring. A fused heterocyclic ring system may include
alicyclic rings
and need include only one heterocyclic ring. Examples of heterocyclyl groups
include
pyridyl, triazolyl, tetrazolyl, indolyl, thienyl, isoimidazolyl, thiazolyl,
furanyl,
tetrahydrofuranyl, quinolinyl, imidazolidinyl and benzothienyl. Compounds
within the
1~ invention containing a heterocyclyl group may occur in two or more
tautometric forms
depending on the nature of the heterocyclyl group; all such tautomeric forms
are included
within the scope of the invention.
When used herein the terms 'lower alkyl', 'lower alkenyl', 'lower alkynyl' and
'alkoxy' include straight and branched chain groups containing from 1 to 6
carbon atoms,
such as methyl, ethyl, propyl and butyl. A particular alkyl group is methyl.
When used herein the term 'halogen' refers to fluorine, chlorine, bromine and
iodine.
In one aspect, examples of RI optionally substituted alkyl include methyl,
isobutyl, carboxymethyl, mercaptomethyl and l-hydroxyethyl. Examples of R1
arylalkyl
incude optionally substituted benzyl. Examples of R 1 aryl include phenyl
optionally
substituted with up to five, preferably up to three, groups selected from
halogen,
mercapto, (C 1 _6) alkyl optionally substituted by 1-3 halo, phenyl, (C 1 _6)
alkoxy
optionally substituted by 1-3 halo, hydroxy(Cl_6)alkyl, mercapto(C1-6)alkyl,
hydroxy,
amino, vitro, carboxy, (C 1 _6) alkylcarbonyloxy, (C I _6)alkoxycarbonyl,
formyl or (C I-6)
alkylcarbonyl groups, preferably unsubstituted phenyl. Examples of R 1
heteroaryl
include indolyf, thienyl, isoimidazolyl, thiazolyl, furyl and benzothienyl,
preferably 2-
thienyl. 2-furyl or 2-benzothienyl.
In another preferred aspect, when R 1 is formula (a), rind A is selected from
2,~-
thienyl. 2.~-furyl. 1.2-phenyl. 1,3-phenyl and 1,4-phenyl, ring B is selected
from phenyl
3~ optionally substituted by one or two hydroxy or by methoxy, dimethylamino,
carboxy,
vitro, amino, acetylamino, trifluoromethoxy or benzyloxy, 2-furyl, 2-, 3- or 4-
pyridyi, 1-
tetrazolyl, 2-tetrazolyl. I-triazolyl. 2-triazolyl, 2 thienyl and imidazolin-
2,5-dione-1-yl
-3-
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WO 99/06365 PCT/EP98/04974
and C is selected from CH2, O or OCH2. in a more preferred aspect R1 is 4-
benzyloxyphenyl 3- or 4-substituted in the benzyl group by asubstituent listed
above for
phenyl or naphthyl. Preferred substituents are carboxy or dimethylamino.
In a further preferred aspect, when Rl is formula (b), rings A and B are both
phenyl, C is O, CH2 or NR10 and D is a bond (p+q=0).
Preferred examples of R 1 include phenyl, (5-benzyl)thien-2-yl, (5-
benzyl)furan-2-
yl, 5-(1-tetrazolylmethyl)thien-?-yl, ~-{2-tetrazolylmethyl)thien-2-yl, S-
(imidazolin-2,5-
dione-1-ylmethyl)thien-2-yl, 5-(1-triazolylmethyl)thien-2-yl, 5-(2-
triazolylmethyl)thien-
2-yl, 3-phenoxyphenyl, 2-phenoxyphenyl, 4-phenoxyphenyl, 3-(4-
hydroxybenzyl)phenyl,
3-(4-methoxybenzyl)phenyl, 4-benzyloxyphenyl, 4-(2-thienylmethyloxy)phenyl, 1-
fluorenyl, 3-(N-ethylcarbazolyl), 4-hydroxybenzyloxy-4-phenyl, 4-
methoxybenzyloxy-4-
phenyl, 4-dimethylaminobenzyloxy-4-phenyl, 4-carboxybenzyloxy-4-phenyl, 3-
carboxybenzyloxy-4-phenyl, (2-pyridyl)-methoxy-4-phenyl, (4-pyridyl)-methoxy-4-
phenyl, 5-[1-(4-carbamoyltriazolyl)-methyl]-thien-2-yl, 5-[1-(4-
carboxytriazolyl)-
methyl]-thien-2-yl, (2-furyl)-methoxy-4-phenyl, dibenzofuranyl, 4-(4-
acetamidobenzyloxy)phenyl, 3-(3-carboxybenzyloxy)phenyl, 3-(4-
carboxybenzyloxy)phenyl, 4-(3-aminobenzyloxy)phenyl, 4-(4-
dimethylaminobenzyloxy)phenyl, 4-(4-benzyloxybenzyloxy)phenyl and 4-(4-
trifluoromethoxybenzyloxy)phenyl.
Suitable examples of R2 include hydrogen,~methyl and benzyl.
R2 is preferably hydrogen.
Examples of R3 include methyl, isobutyl, phenyl-(CH2) 1-~, 1-indanyl, 3,4-
dihydroxybenzyl, 4-hydroxycarbonyl-phenylethyl, 2-trifluoromethylquinolin-6-
yl, 4-
difluoromethoxy-phenylethyl, 3-difluoromethoxyphenylethyl and 3-methyl-2,4,5-
tricarbonylimidazolidin-1-yl.
Preferably R3 is aryl or aryl-(Cl_6)alkyl. R3 is most preferably phenyl.
Examples of R4 include hydrogen, lower alkylcarbonyl, optionally substituted
benzoyl or optionally substituted phenyl lower alkyl carbonyl, more preferably
hydrogen
and acetyl.
R~ is preferably hydrogen.
RS and R6 are preferably independently hydrogen or methyl.
Suitable pharmaceutically acceptable salts of the carboxylic acid group of the
compound of formula (I) (or of other carboxylic acid groups which may be
present as
optional substituents) include those in which R is a metal ion e.g. aluminium
salts, alkali
3~ metal salts (e.g. sodium, lithium or potassium salts), alkaline earth metal
salts (e.g.
calcium or magnesium salts), ammonium salts, and substituted ammonium salts,
for
example those with lower alkylamines (e.g.triethylamine), hvdroxy-lower
alkvlamines
_4_
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WO 99/06365 PCT/EP98/04974
(e.g. 2-hydroxyethylamine), bis-(2-hydroxyethyl)amine, tris-(2-hydroxyethyl)
amine,
lower-cycloalkylamines (e.g. dicyclohexyl-amine), or with procaine,
dibenzylamine,
~1,N-dibenzyl- ethylenediamine, 1-ephenamine, N-methylmorpholine, N-
ethylpiperidine,
N-benzyl-~3-phenethylamine, dehydroabietylamine, ethylenediamine,
N,N'-bishydroabietylethylenediamine, bases of the pyridine type (e.g.
pyridine, collidine
and quinoline), and other amines which have been or can be used to form
quaternary
ammonium salts.
Pharmaceutically acceptable salts may also be acid addition salts of any amino
or
substituted amino groups) that may be present as optional substituents on the
compound
of formula (I), or of a heterocyclic group ring nitrogen atom. Suitable salts
include for
example hydrochlorides, sulphates; hydrogen sulphates, acetates, phosphates
etc. and
other pharmaceutically acceptable salts will be apparent to those skilled in
the art.
Suitable addition salts are the hydrochlorides and hydrogen sulphates.
Preferred salts are sodium salts.
Examples of suitable pharmaceutically acceptable in vivo hydrolysable ester-
forming groups R include those forming esters which break down readily in the
human
body to leave the parent acid or its salt. Suitable groups of this type
include those of part
formulae (i), (ii), (iii), (iv) and (v):
Ra
-CH-O.CO.Rb
R°
R~-NC Re (ii)
-CH2-OR' (iii)
Ra
O-CO-CH-R9 (iv)
-CHOCO
RkOC R~
\ (v)
Rh R'
-5-
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WO 99/06365 PCT/EP98/04974
wherein Ra is hydrogen, (C1_6) alkyl, (C3_~} cycloalkyl, methyl, or phenyl, Rb
is
(C 1 _6) alkyl, (C 1_6) alkoxy, phenyl, benzyl, (C3_~) cycloalkyl, (C3_~)
cycloalkyloxy,
(Cl_6) alkyl (C3_~) cycloalkyl, 1-amino (C1_6) alkyl, or 1-(C1_6 alkyl)amino
(C1-6}
alkyl: or Ra and Rb together form a 1,2-phenylene group optionally substituted
by one or
two methoxy groups; Rc represents (C 1 _6) alkylene optionally substituted
with a methyl
or ethyl group and Rd and Re independently represent (C 1 _6) alkyl; Rf
represents (C 1-6)
alkyl; R5 represents hydrogen or phenyl optionally substituted by up to three
groups
selected from halogen, (C 1 _6) alkyl, or (C 1 _6) alkoxy; Q is oxygen or NH;
Rh is
hydrogen or (Cl_6) alkyl; Rt is hydrogen, (Cl_6) alkyl optionally substituted
by halogen,
(C2_6) alkenyl, (C1_6) alkoxycarbonyl, aryl or heteroaryl; or Rh and Rt
together form
(C 1 _6) alkylene; RJ represents hydrogen, (C 1 _6) alkyl or (C 1_6)
alkoxycarbonyl; and Rk
represents (C 1 _g) alkyl, (C 1 _g) alkoxy, (C 1 _6) alkoxy(C 1 _6)alkoxy or
aryl.
Examples of suitable in vivo hydrolysable ester-forming groups include, for
example, acyloxyalkyl groups such as acetoxymethyl, pivaloyloxymethyl,
a-acetoxyethyl, a-pivaloyloxyethyl, 1-(cyclohexylcarbonyloxy)prop-1-yl, and
(1-aminoethyl)carbonyloxymethyl; alkoxycarbonyloxyalkyl groups, such as
ethoxycarbonyloxymethyl, a-ethoxycarbonyloxyethyl and propoxycarbonyloxyethyl;
dialkylaminoalkyl especially di-loweralkylamino alkyl groups such as
dimethylaminomethyl, dimethylaminoethyl, diethylaminomethyl or
diethylaminoethyl;
2-(alkoxycarbonyl)-2-alkenyl groups such as 2-(isobutoxycarbonyl)pent-2-enyl
and
2-(ethoxycarbonyl)but-2-enyl; and lactone groups such as phthalidyl and
dimethoxyphthalidyl.
A further suitable pharmaceutically acceptable in vivo hydrolysable ester-
forming
Group is that of the formula:
CHz R''
0, ,0
0O
wherein Rk is hydrogen, C l _6 alkyl or phenyl.
R is preferably hydrogen.
It will be appreciated that also included within the scope of the invention
are
pharmaceutically acceptable Salts and pharmaceutically acceptable esters,
including in
vivo hydrolysable esters, of anv carboxy groups that may be present as
optional
substituents in compounds of formula (I).
Some compounds of formula (I) may be crystallised or recrystallised from
solvents such as organic solvents. In such cases solvates may be formed. This
invention
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includes within its scope stoichiometric solvates including hydrates as well
as compounds
containing variable amounts of solvents such as water that may be produced by
processes
such as lyophilisation. Compounds of formula (I) may be prepared in
crystalline form by
for example dissolution of the compound in water, preferably in the minimum
quantity
thereof, followed by admixing of this aqueous solution with a water miscible
organic
solvent such as a lower aliphatic ketone such as a di-(C I _6) alkyl ketone,
or a (C 1-6)
alcohol, such as acetone or ethanol.
The compounds of formula (I) are metallo-(3-lactamase inhibitors and are
intended
for use in phatTrtaceuticaI compositions. Therefore it will readily be
understood that they
are preferably each provided in substantially pure fotTn, for example at least
60% pure,
more suitably at least 75% pure and preferably at least 85% pure, especially
at least 95%
pure particularly at least 98%.pure (% are on a weight for weight basis).
Impure
preparations of the compounds may be used for preparing the more pure forms
used in the
pharmaceutical compositions; these less pure preparations of the compounds
should
contain at least 1%, more suitably at least 5% and preferably from 10 to 59%
of a
compound of the formula (I) or salt, solvate or in vivo hydrolysable ester
thereof.
The present invention also provides a process for the preparation of a
compound
of formula {I) as defined above, which comprises reacting a compound of
formula (II)
Y-C(RS'R6')-C(=CHR3')-CO-W
(II)
with a compound of formula (III)
X 1-CH(R 1')-CO~Rx
(III)
wherein W is a leaving group, Y is R4'S or a croup convertible thereto, Rx is
R or
a carboxylate protecting group, X 1 is N3 or NHR,,' and R 1'. R~', R3', R4',
RS' and R6' are
R1, R~, R3, R4, RS and R6 or groups convertible thereto, wherein R, Rl, R~,
R~, R~. RS
and R6 are as defined in formula (I), and thereafter, where necessary,
converting Y into
RD'S, Rx, R 1', R~', R3' R4', RS' and/or R6' into R, R 1, R~, R3, R~, R~
and/or R6 and
optionally inter-converting R, Rl, R2, R3, R~, RS andlor R6.
Suitable ester-forming carboxyl-protecting groups Rx other than in vivo
hydrolysable ester forming groups are those which may be removed under
conventional
conditions. Such Groups for R~ include methyl. ethyl, benzyl, p-methoxybenzyl.
3~ benzoylmethyl, p-nitrobenzyl. 4-pyridylmethyl, 2,2.2-trichloroethyl, 2,2,2-
tribromoethyl.
t-butyl, t-amyl, allyl, diphenylmethyl, triphenylrnethyl, adamantyl, 2-
benzyloxyphenvl.
:I-methylthiophenyl, tetrahydrofur-2-yl, tetrahydropyran-2-yl,
pentachlorophenyl.
*rB
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acetonyl, p-toluenesulphonylethyl, methoxymethyl, a silyl (such as
trimethylsilyl),
stannyl or phosphorus- containing group or an oxime radical of formula -
N=CHR12
where R 12 is aryl or heterocyclyl, or an in vivo .hydrolysable ester radical
such as defined
above.
Certain compounds of formulae (II) and (III) may include an amino group which
may be protected. Suitable amino protecting groups are those well known in the
art
which may be removed under conventional conditions if required without
disruption of
the remainder of the molecule.
Examples of amino protecting groups include (C 1 _6) alkanoyl; benzoyl; benzyl
optionally substituted in the phenyl ring by one or two substituents selected
from (C 1-~)
alkyl, (C 1-4) alkoxy, trifluoromethyl, halogen, or nitro; (C 1-q.)
alkoxycarbonyl;
benzyIoxycarbonyl or trityl substituted as for benzyl above; allyloxycarbonyl,
trichloroethoxycarbonyl or chloroacetyl.
When X1 in the compound of formula (III) is NHR2', the compound is preferably
presented as the anion prepared by treatment of the amine with an organic base
such as
triethylamine, pyridine or morpholine, and suitable examples of the leaving W
group in
the compound of formula (II) include halo such as chloro and mixed sulphonic
anhydrides such as those where W is methanesulphonyloxy, toluene-p-
sulphonyloxy or
trifluoromethanesulphonyloxy in mixed sulphonic anhydrides. The compound of
formula
(III) may be presented as the trimethylsilyl ester hydrochloride.
The reaction of the compounds of formula (II) and (BI) is preferably carried
out at
ambient temperature, for example 15-25°C, in an inert solvent such as
chloroform
tetrahydrofuran, dichloromethane, dioxan or dimethylformamide.
When X in the compound of formula (III) is N3, the leaving group W in the
compound of formula (II) is preferably SH and the reaction is carried out at
elevated
temperature, such as at reflux, in an inert solvent such as toluene.
Examples of Y convertible into RD'S include halo such as bromo which may be
displaced by thiobenzoic acid or thioacetic acid.
Examples of groups R1', R,,', R3', R~' convertible to Rl, R~. R3 and R4
include
those where any carboxy or amino~group is protected by carboxy or amino
protecting
groups. Additionally, examples of R l' convertible to R 1 include those
containing ring A
substituted by hydroxy which can generate R l groups of formula (a) where
linker C is of
the form -O-(CRgR9)q- and where ring B is an aromatic ring or heterocycle,
optionally
substituted. This may be effected, for example, by alkylation of the hydroxy
substituent
3~ with a benzyl bromide derivative or with a heterocyclylalkyl bromide
derivative.
Alternatively, the hydroxy group may be coupled with a benzyl alcohol
derivative or with
a heterocyclylalkvl alcohol derivative in established ways, for example in the
presence of
_g_
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WO 99/06365 PCT/EP98/04974
diethyl azodicarboxylate and triphenylphosphine (Mitsunobo et al, Bull. Chem.
Soc. Jpn.,
1967, 40, 2380).
R4' in the compound of formula (II) is preferably other than hydrogen, such as
an
acyl protecting group as described above for carboxy protecting groups, for
example
acetyl.
The acid derivative of formula (II) is preferably prepared from the
corresponding
free acid by treatment with strong base such as sodium hydride followed by a
source of
the anion leaving group W, such as oxalyl chloride where W is CI, or hydrogen
sulphide
where W is SH.
The initial product of the reaction of compounds of formulae {II) and (III} is
a
compound of formula (IV):
Y-C(R5'R6')-C(=CHR3')-CON(R2')-CH(R 1')-C02R"
(IV)
wherein the variables are as defined in formulae (II) and {III). Novel
intermediates of formula (IV) wherein R" is other than R when R1', R2', R3',
R4', R~' and
R6' are R1, R2, R3, R4, RS and R6 also form part of the invention. In one
aspect Y is
R4'S.
Compounds of formula {IV) where R1' is -(A)-OH or-(A)-CH20H may be
converted to compounds with R1 as defined in (a) where C is -OCH2- or -CH20-
using
alcohols of formula (B')-CH20H or (B')-OH, respectively under Mitsunobu
conditions
(Synthesis 1981, I), using a coupling reagent such as triphenyl phosphine and
diethyl
azodicarboxylate: B' is B or a group convertible thereto, for example where a
carboxy or
amino substituent on B is protected.
When Rx is other than hydrogen, the carboxy group -COORx may be deprotected,
that is to say, converted to a free carboxy, carboxy salt or carboxy ester
group -COOR in
a conventional manner, for example as described in EP0232966A.
Simultaneous deprotection of -COORx and R4'S and any protecting group in R 1'
may be achieved by treatment with sodium sulphide nonahydrate in
water/methanoi.
When it is desired to obtain a free acid or salt of the preferred isomer of
the
formula (I) from an isomeric mixture, this may be effected by chromatographic
separation
of the isomers of the product. Where this is an ester and/or where R~' is
other than
hydrogen, the desired isomer may then be deprotected to give the corresponding
free acid
or salt. In some cases, however, it has been found particularly convenient
first to
deprotect the isomeric mixture to give an isomeric mixture of the free acid or
salt of
formula (I), followed by fractional recrystallisation to give the desired acid
or salt isomer.
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Where *D isomer of formula (I) is desired, it is preferred to use the
corresponding *D
isomer of the intermediate of formula (III).
A carboxyl group may be regenerated from any of the above esters by usual
methods appropriate to the particular Rx group, for example, acid- and base-
catalysed
hydrolysis, or by enzymically-catalysed hydrolysis, or by hydrogenolysis under
conditions wherein the remainder of the molecule is substantially unaffected.
For
example, in the case of acetonyl, by hydrolysis in acetonitrile with O.1M
aqueous
potassium hydroxide solution.
Pharmaceutically acceptable salts may be prepared from such acids by treatment
with a base, after a conventional work-up if necessary. Suitable bases include
sodium
hydrogen carbonate to form sodium salts.
Crystalline forms of the compounds of formula (I) where R is a salt forming
canon may for example be prepared by dissolving the compound (I) in the
minimum
quantity of water, suitably at ambient temperature, then adding a water
miscible organic
solvent such as a (C1-6) alcohol or ketone such as ethanol or acetone, upon
which
crystallisation occurs and which may be encouraged for example by cooling or
trituration.
Compounds of formulae (II) and (III) are known compounds or may be prepared
by procedures analogous to those described in the prior art.
Compounds of formula (II) may be prepared from the readily available
a-substituted cinnamic acids (IIA):
R3'CH=C(CRS'R6'H)-C02H (IIA)
for example, by bromination of an a-methylcinnamic acid in carbon
tetrachloride using
N-bromosuccinimide under tungsten lamp illumination to give an a-
bromomethylcinnamic acid of formula (IIB).
2~ R3'CH=C(CR5'R6'Br)-C02H (IIB)
Compounds of formula (II) where Y is RD'S may be obtained from compounds of
formula (II) where Y is a group convertible into R4'S such as halo, e.g.
bromo, which
may be displaced by thiobenzoic acid or thioacetic acid in the presence of an
amine such
as triethvlamine.
Compounds of formula (III) may be prepared by procedures analogous to those
described in the prior art references listed above.
Novel compounds of formula (III), which are a-amino acids, may be prepared by
any conventional amino acid synthesis, for example from the corresponding a-
keto ester
R ~'-CO-CO,,Rx via the oxime ester R ~'-C(=N-OH)-CO~Rr by conventional routes.
'Che
3~ a-keto ester is obtainable from the R ~'-H, R ~'-CH~CO~R't or R ~'-CO~Rx by
routine
methods (J. Llarch, vide infra). Alternatively the compounds of formula (III)
may be
prepared from the aldehyde intermediate R ~'-CHO by the Strecker synthesis
[cf: Advanced
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Organic Chemistry; Mechanism and Structure, 4th Edn, by J. March, Section 6-
50, p.965;
1992, John Wiley and Sons Inc, ISBN 0-471-60180-2] or by the method of
Monianari et al.
(Synthesis 1979, 26). The invention also extends to novel compounds of formula
(III).
A compound of formula (I) or a salt, solvate or in vivo hydrolysable ester
thereof,
may be administered in the form of a pharmaceutical composition together with
a
pharmaceutically acceptable carrier and the invention also relates to such
compositions.
The compounds of formula (I) have metallo-~i-lactamase inhibitory properties,
and are
useful for the treatment of infections in animals, especially mammals,
including humans, in
particular in humans and domesticated (including farm)animals. The compounds
may be
used, for example, for the treatment of infections of, inter alia, the
respiratory tract, the
urinary tract, and soft tissues and blood, especially in humans.
Accordingly, the invention further provides a method of treatment of bacterial
infections in humans or animals which comprises administering, in combination
with a ~-
lactam antibiotic, a therapeutically effective amount of a compound of formula
(I) or a
pharmaceutically acceptable salt, solvate or in vivo hydrolysable ester
thereof.
The compounds may be used in combination with an antibiotic partner for the
treatment of infections caused by metallo-(3 -lactamase producing strains, in
addition to
those infections which are subsumed within the antibacterial spectrum of the
antibiotic
partner. Metallo-(3-laetamase producing strains include:- Pseecdomonas
aeruginosa,
Klebsiella pneumoniae, Xanthomonas maltophilia, Bacteroides fragilis, Serratia
marcescens, Bacteroides distasonis, Pseudomonas cepacia, Aeromonas hydrophila,
rlerornonas sobria, Aeromonas salmonicida, Bacillus cereces, Legionella
gormanii and
Flavobactericcm spp.
It is generally advantageous to use a compound according to the invention in
admixture or conjunction with a carbapenem, penicillin, cephalosporin or other
~i-lactam
antibiotic and that can result in a synergistic effect, because of the metallo-
~i-lactamase
inhibitory properties of the compounds according to the invention. In such
cases, the
compound of formula (I) and the (3-lactam antibiotic can be administered
separately or in
the form of a single composition containing both active ingredients as
discussed in more
detail below. The compositions of the invention include those in a form
adapted for oral,
topical or parenteral use and may be used for the treatment of bacterial
infection in
mammals including humans. The compounds of formula (I) are particularly
suitable for
parenteral administration.
The compounds of formula (I) may be formulated for administration in any
3~ convenient way for use in human or veterinary medicine, by analogy with
other
antibiotics and other (3-lactam antibiotic/~i-lactamase inhibitor
combinations.
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WO 99/06365 PCT/EP98/04974
The composition may be formulated for administration by any route, such as
oral,
topical or parenteral. The compositions may be in the form of tablets,
capsules, powders,
granules, lozenges, creams or liquid preparations, such as oral or sterile
parenteral
solutions or suspensions.
The topical formulations of the present invention may be presented as, for
instance, ointments, creams or lotions, eye ointments and eye or ear drops,
impregnated
dressings and aerosols, and may contain appropriate conventional additives
such as
preservatives, solvents to assist drug penetration and emollients in ointments
and creams.
The formulations may also contain compatible conventional carriers, such as
cream or ointment bases and ethanol or oleyl alcohol for lotions. Such
carriers may be
present as from about 1 % up to about 98% of the formulation. More usually
they will
form up to about 80% of the formulation.
Tablets and capsules for oral administration may be in unit dose presentation
form, and may contain conventional excipients such as binding agents, for
example syrup,
acacia, gelatin, sorbitol, tragacanth, or polyvinylpyrollidone; fillers, for
example lactose,
sugar, maize-starch, calcium phosphate, sorbitol or glycine; tabletting
lubricants, for
example magnesium stearate, talc, polyethylene glycol or silica;
disintegrants, for
example potato starch; or acceptable wetting agents such as sodium lauryl
sulphate. The
tablets may be coated according to methods well known in normal pharmaceutical
practice. Oral liquid preparations may be in the foim of, for example, aqueous
or oily
suspensions, solutions, emulsions, syrups or elixirs, or may be presented as a
dry product
for reconstitution with water or other suitable vehicle before use. Such
liquid
preparations may contain conventional additives, such as suspending agents,
for example
sorbitol, methyl cellulose, glucose syrup, gelatin, hydroxyethyl cellulose,
carboxymethyl
cellulose, aluminium stearate gel or hydrogenated edible fats, emulsifying
agents, for
example lecithin, sorbitan monooleate, or acacia; non-aqueous vehicles (which
may
include edible oils), for example almond oil, oily esters such as glycerine,
propylene
glycol, or ethyl alcohol; preservatives, for example methyl or propyl p-
hydroxybenzoate
or sorbic acid, and, if desired, conventional flavouring or colouring agents.
Suppositories will contain conventional suppository bases, e.g. cocoa-butter
or
other glyceride.
For parenteral administration, tluid unit dosage forms are prepared utilizing
the
compound and a sterile vehicle, water being preferred. The compound, depending
on the
vehicle and concentration used, can be either suspended or dissolved in the
vehicle. In
3~ preparing solutions the compound can be dissolved in water for injection
and filter
sterilised before filling into a suitable vial or ampoule and sealing.
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Advantageously, agents such as a local anaesthetic, preservative and buffering
agents can be dissolved in the vehicle. To enhance the stability, the
composition can be
frozen after filling into the vial and the water removed under vacuum. The dry
lyophilized powder is then sealed in the vial and an accompanying vial of
water for
injection may be supplied to reconstitute the liquid prior to use. Parenteral
suspensions
are prepared in substantially the same manner except that the compound is
suspended in
the vehicle instead of being dissolved and sterilisation cannot be
accomplished by
filtration. The compound can be sterilised by exposure to ethylene oxide
before
suspending in the sterile vehicle. Advantageously, a surfactant or wetting
went is
included in the composition to facilitate uniform distribution of the
compound.
The compositions may contain from 0.1 % by weight, preferably from 10-60% by
weight, of the active material, depending on the method of administration.
Where the
compositions comprise dosage units, each unit will preferably contain from 50-
500 mg of
the active ingredient. The dosage as employed for adult human treatment will
preferably
range from 100 to 3000 mg per day, for instance 1500 mg per day depending on
the route
and frequency of administration. Such a dosage corresponds to 1.5 to 50 mg/kg
per day.
Suitably the dosage is from 5 to 20 mg/kg per day.
No toxicological effects are indicated when a compound of formula (I) or a
pharmaceutically acceptable salt thereof is administered in the above-
mentioned dosage
range.
A composition according to the invention may comprise a compound of formula
(I)
or a salt, solvate or in vivo hydrolysable ester thereof together with one or
more additional
active ingredients or therapeutic ajents, for example a ~-lactam antibiotic
such as a
carbapenem, penicillin or cephalosporin or pro-drug thereof. Carbapenems,
penicillins,
cephalosporins and other (3-lactam antibiotics suitable for co-administration
with the
compound of formula (I) - whether by separate administration or by inclusion
in the
compositions according to the invention - include both those known to show
instability to
or to be otherwise susceptible to metallo-(3-lactamases and also those known
to have a
degree of resistance to metallo-~i-lactamases.
A serine (3-lactamase inhibitor such as clavulanic acid, sulbactam or
tazobactam
may also be co-administered with the compound of the invention and the [3-
lactam
antibiotic. either by separate administration, or co-formulation with one,
other or both of
the compounds of the invention and the (3-lactam antibiotic.
Examples of carbapenems that may be co-administered with the compounds
according to the invention include imipenem, rneropenem, biapenem, BMS 181139
([:1R-
[4alpha,5beta,6beta(R*)]]-4-[2-[(aminoiminomethyl)amino]ethyl]-3-[(2-
cyanoethyl)thio]-
6-(1-hydroxyethyl)-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylic acid).
B02727 ([4R-
-l3-
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3[3S*,SS*(R*)],4alpha,Sbeta,6beta(R*)]]-6-(1-hydroxyethyl) -3-[[5-[1-hydroxy-3-
(methylamino)propyl]-3-pyrrolidinyl]thio]-4-methyl-7-oxo-I-azabicyclo[3.2.0]
hept-2-ene-
2-carboxylic acid monohydrochloride), ER35786 ((1R, SS, 6S)-6-[1(R)-
Hydroxymethyl]-2-
[2(S)-[1(R)-hydroxy-1-[pyrrolidin-3(R)-yl] methyl]pyrrolidin-4(S)-ylsulfanyl]-
1-methyl-1-
carba-2-penem-3-carboxylic acid hydrochloride) and S4661 ((1R,SS,6S)-2-
[(3S,SS)-~-
(sulfamoylaminomethyl) pyrrolidin-3-yl]thio-6-[{1R)-1-hydroxyethyl]-1-
methylcarbapen-
2-em-3-carboxylic acid).
Examples of penicillins suitable for co-administration with the compounds
according to the invention include benzylpenicillin, phenoxymethylpenicillin,
carbenicillin,
azidocillin, propicillin, ampicillin, amoxycillin, epicillin, ticarcillin,
cyclacillin,
pirbeniciIlin, azlocillin, mezlocillin, sulbenicillin, piperacillin, and other
known penicillins.
The penicillins may be used in the form of pro-drugs thereof, for example as
in vivo
hydrolysable esters,for example the acetoxymethyl, pivaloyloxymethyl,
oc-ethoxycarbonyloxyethyl and phthalidyl esters of ampicillin,
benzylpenicillin and
amoxycillin; as aldehyde or ketone adducts of penicillins containing a 6-a-
aminoacetamido
side chain (for example hetacillin, metampicillin and analogous derivatives of
amoxycillin); and as a,-esters of carbenicillin and ticarcillin, for example
the phenyl and
indanyl a-esters.
Examples of cephalosporins that may be co-administered with the compounds
according to the invention include, cefatrizine, cephaloridine, cephalothin,
cefazolin,
cephalexin, cephacetrile, cephapirin, cephamandole nafate, cephradine,
4-hydroxycephalexin, cephaloglycin, cefoperazone, cefsulodin, ceftazidime,
cefuroxime,
cefmetazole, cefotaxime, ceftriaxone, and other known cephalosporins, all of
which may be
used in the form of pro-drugs thereof.
2~ Examples of ~-lactam antibiotics other than penicillins and cephalosporins
that may
be co-administered with the compounds according to the invention include
aztreonam,
latamoxef (Moxalactam - Trade Mark), and other known (3-lactam antibiotics,
all of which
may be used in the form of pro-drugs thereof.
Particularly suitable penicillins for co-administration with the compounds
according
to the invention include ampicillin, amoxycillin, carbenicillin, piperacillin,
azlocillin,
mezlocillin, and ticarcillin. Such penicillins may be used in the form of
their
pharmaceutically acceptable salts, for example their sodium salts.
Alternatively, ampicillin
or amoxycillin may be used in the form of fine particles of the zwitterionic
form (generally
as ampicillin trihydrate or amoxvcillin trihydrate) for use in an injectable
or infusable
3~ suspension, for example, in the manner hereinbefore described in relation
to the
compounds according to the invention. Amoxycillin, for example in the form of
its sodium
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WO 99/06365 PCT/EP98/04974
salt or the trihydrate, is particularly preferred for use in synergistic
compositions according
to the invention.
Particularly suitable cephalosporins for co-administration with the compounds
according to the invention include cefotaxime and ceftazidime, which may be
used in the
form of their pharmaceutically acceptable salts, for example their sodium
salts.
A compound of formula (I) may be administered to the patient in conjunction
with a
(3-lactam antibiotic such as a carbapenem, penicillin or cephalosporin in a
synergistically
effective amount.
The compounds of formula (I) may suitably be administered to the patient at a
daily
dosage of from 0.7 to 50 mg/kg of body weight. For an adult human (of
approximately 70
kg body weight), from 50 to 3000 mg, preferably from 100 to 1000 mg, of a
compound
according to the invention may be administered daily, suitably in from 1 to 6,
preferably
from 2 to 4, separate doses. Higher or lower dosages may, however, be used in
accordance
with clinical practice.
When the compositions according to the invention are presented in unit dosage
form,
each unit dose may suitably comprise from 25 to 1000 mg, preferably from 50 to
500 mg,
of a compound according to the invention. Each unit dose may, for example, be
62.5, 100,
125, 150, 200 or 250 mg of a compound according to the invention.
When the compounds of formula (I) are co-administered with a penicillin,
cephalosporin, carbapenem or other (3-lactam antibiotic, the ratio of the
amount of the
compound according to the invention to the amount of the other ~3-lactam
antibiotic may
vary within a wide range. The said ratio may, for example, be from 100:1 to
1:100; more
particularly, it may, for example, be from 2: i to 1:30.
The amount of carbapenem, penicillin, cephalosporin or other (3-lactam
antibiotic
in a synergistic composition according to the invention will normally be
approximately
similar to the amount in which it is conventionally used her ~e_, for example
from about 50
mg, advantageously from about 6~.5 mg, to about 3000 mg per unit dose, more
usually
about 125, 250, 500 or 1000 mg per unit dose.
The present invention further provides a compound of formula {I) or a
pharmaceutically acceptable salt, solvate or in vivo hydrolysable ester
thereof for use in
the treatment of bacterial infections.
The present invention also includes the use of a compound of formula (I) or a
pharmaceutically acceptable salt, solvate or in vivo hydrolvsable ester
thereof, in the
manufacture of a medicament for the treatment of bacterial infections
The present invention also includes the use of a compound of formula (I) or a
pharmaceutically acceptable salt, solvate or in vivo hydrolysable ester
thereof as a
metallo-~i-lactamase inhibitor.
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All the above compositions and methods may optionally include a serine ~-
lactamase inhibitor as above described.
The compounds of the present invention are active against metallo-(3-lactamase
enzymes produced by a wide range of organisms including both Gram-negative
organisms and Gram-positive organisms.
The following Examples illustrate compounds useful in the present invention,
and
intermediates in their preparation. (Atl temperatures are in °C).
EXAMPLES
Description 1
(E)-a-Bromomethylcinnamic acid
A solution of a-methylcinnamic acid (Aldrich) ( 1.62g, lOmmol) and N-
bromosuccinimi.de ( 1.78g, lOmmoI) in carbon tetrachloride (20m1) was refluxed
under illumination ( 150W; tungsten lamp) for 30 minutes. The solution was
cooled to room temperature, filtered and evaporated to give the title compound
(0.558, 23%); 8H (CDCI3) 4.42 (2H, s), 7.40-7.70 (SH, m), 7.97 (1H, s); mJz
(ES-) 239,241 (M-H).
Description 2
(E)-a-Acetylthiomethylcinnamic acid
A solution of (E~-a-bromomethylcinnamic acid (540mg) in ethyl acetate
(20m1) was created with triethylamine (0.74m1) and thiolacetic acid (0.18m1).
After lh at room temperature the solution was washed with IM hydrochloric
acid (15m1), water (3 x l5ml), brine (ISmI) and was dried (MgS04) and
evaporated to yield the title compound (590mg, 100%); 8H (CDCl3) 2.35 (3H,
s), 4.09 (2H, s), 7.43 (5H, m), 7.95 (1H, s); m/z (ES-) 235 (M-H).
Description 3
Methyl p-hydroxy-(D]-phenylglycinate
The title compound was prepared from D-p-hydroxyphenylglycine by stirring in
methanol, presaturated with hydrogen chloride gas, overnight. The methanol was
removed under reduced pressure and the residue partitioned between ethyl
acetate and an
excess of saturated NaHC03 solution. The organic layer was washed with water
and
dried and solvent removed.
Description 4
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N-(E-oc-Acetyithiomethyl-3-phenylprop-2-enoyl) p-hydroxy-[D]-
phenylglycinate
A solution of (E~-ot-acetylthiomethylcinnamic acid (Description 2,
1 mmol) in dichloromethane (Sml) at room temperature was treated with oxalyl
chloride (0.3m1) and N,N-dimethyl-formamide (1 drQp). After 30 minutes, the
solution was evaporated and then re-evaporated from dichloromethane (2 x Sml).
The acid chloride in dichloromethane (Sml) was added dropwise to an ice-cold
solution of methyl p-hydroxy-[D]-phenylglycinate (Description 3, lmmol) and
triethylamine (0.35m1, 2.Smmol) in dichloromethane ( l5ml). The reaction
mixture was warmed to room temperature and stirred for 2h. The mixture was
washed with water (2 x lOml), brine (lOml), was dried (MgS04) and evaporated.
Flash-chromatography on silica, eluting with 10-25% ethyl acetate in hexane
gave the title compound (O.SmmoI), mlz (ES+) 400 (MH'~).
Description 5
N-(E-a-Acetylthiomethyl-3-phenylprop-2-enoyl) p-(m-methoxycarbonyl)-
benzyloxyphenylglycine methyl ester
To a stirred solution of the p-hydroxyphenylglycine derivative from
Description 4,
(O.Smmol) in dry tetrahydrofuran was added triphenylphosphine (0.6mmo1) and m-
methoxycarbonylbenzyl alcohol (0.6mmo1), follov~ied by diethyl
azodicarboxylate
(0.6mmol). The yellow solution was stirred at room temperature for l5min and
then
diluted with ethyl acetate. The organic layer was washed with water and dried
(MgSO,).
The solvent was removed to afford a gum which was chromatographed on silica
gel.
Elution with 25% ethyl acetate in hexane the title compound as a gum
(235mg;0.42mmol), EIMS M' 547.
Description 6
D-Phenylglycine methyl ester
Acetyl chloride (4m1) was added cautiously and dropwise to methanol (2Om1) at
0"C over
2 minutes. When the addition was completed, D-phenylgIycine ( 1 g, 5.9 mmol,
Aldrich)
was introduced in a single portion. The mixture was stirred until dissolved
then allowed
to stand at RT for 24 hours. The solvent was evaporated then coevaporated
twice from
toluene to afford D-Phenylglycine methyl ester hydrochloride as a white
crystalline solid
in quantitative yield.
3~ 8H (CD,OD) 3.80 (3H, s, Me0), 5.19 { 1 H, s, HCN), 7.42-7.~0 (SH, m, Ar-H).
The title compound was obtained from the hydrochloride by treatment with
triethylamine
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Description 7
iVlethyl [D]-N-(E-a-acetylthiomethyl-3-phenylprop-2-enoyl)phenylglycinate
A solution of (E)-a-acetylthiomethylcinnamic acid (Description 2)
(236mg, lmmol) in dichloromethane (5ml) at room temperature was treated with
oxalyl chloride (0.3m1) and N,N-dimethyl-formamide (1 drop). After 30
minutes, the solution was evaporated and then re-evaporated from
dichloromethane (2 x Sml). The acid chloride in dichloromethane (Sml) was
added dropwise to an ice-cold solution of methyl D-phenylglycinate
(Description
6) (202mg, lmmol) and triethylamine (0.35m1, 2.Smmol) in dichloromethane
( 15m1). The reaction mixture was warmed to room temperature and stirred for
2h. The mixture was washed with water (2 x lOml), brine (lOml), was dried
(MgS04) and evaporated. Flash-chromatography on silica, eluting with 10-25%
ethyl acetate in hexane gave the title compound {194g, 51%); b[(CD3)2S0] 2.31
(3H, s), 3.65 (3H, s), 3.98 {2H, s), 5.53 (1H, s, J=7.OHz), 7.38 (IOH, m),
8.96
( 1 H, d, J = 7Hz); m/z (ES+) 384 (MH+)
Example 1
N-(E-a-Mercaptomethyl-3-phenyl-prop-2-enoyl)-p-{m-carboxy)-benzyloxy-[D]-
phenylglycine
The methyl ester (100mg; 0.2mmo1) from Description S was suspended in
methanol (3m1) and treated with a solution of sodium sulphide nonahydrate
(200mg;
0.84mmo1) in water (2m1). The suspension was stirred under argon for 3 hours.
The
2~ reaction mixture was washed with ethyl acetate and the aqueous layer was
acidified by
addition of SM hydrochloric acid solution (10 drops) and then extracted with
ethyl
acetate. The organic layer was washed with water and dried (MgSO,). Removal of
the
solvent afforded title compound as a foam (0.1 mmol), APCI [M-H]~ 476.
Example 2
N-(E-a-Mercaptomethyl-3-phenylprop-2-enoyl)-[D]-phenylglycine
A solution of methyl [D]-N-(E'-a-acetylthiomethyl-3-phenylprop-2-
enoyl) phenyiglycinate (Description 7) ( 185mg) in methanol (Sml) at room
temperature was treated with a solution of sodium sulphide nonahydrate (350mg)
3~ in water (2.Sm1). After 40 minutes, the solution was diluted with ethyl
acetate
{25m1), was washed with 1 M hydrochloric acid ( I Oml), water (2 x l Oml), and
then dried (MgS04) and evaporated. The residue was flash-chromato~raphed on
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WO 99/06365 PCT/EP98/04974
silica, eluting with 5% grading to 10% methanol in dichloromethane to give the
title compound (114mg, 72%); b[CD3)2S0] 3.53 (2H, s), 5.22 (1H, d, J 6.8Hz),
7.05-7.55 ( 1H, m), 8.38 ( 1 H, d, J = 6.8Hz); m/z (ES-) 326 (M-H).
BIOLOGICAL ACTIVITY
ho screen
The inhibitory activity of the compounds of the invention is measured in 25mM
PIPES pH 7 buffer at 10 concentrations (1000, 333, 111, 37, 12.3, 4.1, 1.4,
0.46, 0.15 and
O.OS~M) at 37°C using nitrocefin (9l~tM final concentration) as the
reporter substrate.
The assays are performed with a 5 minute preincubation of enzyme and inhibitor
and are
conducted in the presence of added zinc sulphate (Zn''' 100~,M, final
concentration). The
methodology is described in detail in the following references: Payne et al
(1991), J.
Antimicrob. Chemother., 28:255; Payne et al ( 1994), Antimicrob. Agents and
Chemother.,
1 S 38:767.
Results
Compounds of the invention may be tested and found to inhibit Bacteroides
fragilis CfiA metallo-(3-lactamase with I50 values <10001tM.
The compound of the Example 2 exhibits ari Iso value against B. fragilis CfiA
metallo-(3-lactamase of <lp.M and exhibited significant inhibition of the
Stenotrophomonas maltophiIia L-1 (formerly Xanthomonas maltophilia L-1) and
Bacillus cereus II metallo-~i-lactamases, with ISa values in the range 0.2 -
l4~tM.
Antibacterial activity of compounds of the invention in combination with the
carbapenem antibiotic, meropenem, against the Bacteroides fragilis 262 strain,
which produces CfiA metallo-(3-lactamase:-
[MIC = minimum inhibitory concentration (p.g/ml)]
Antibacterial activity of meropenem was potentiated as follows:
MIC (p.g/ml) of meropenem alone: >128
MIC (p.a/ml) MIC (ug/ml) of meropenem
of
Inhibitor compound in the presence of
compound atone8p.g/ml of
com ound
Exam le 2 >256 8
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