Organic compounds -- part of the class 532-570 series – Organic compounds – Amino nitrogen containing
Reexamination Certificate
2002-05-20
2004-03-02
Kumar, Shailendra (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Amino nitrogen containing
C564S169000
Reexamination Certificate
active
06700017
ABSTRACT:
FIELD OF THE INVENTION
The present application relates to a plurality of novel processes for preparing 2-(2-hydroxyphenyl)-2-(alkoxyimino)-N-methylacetamide derivatives, to novel intermediates for their preparation, and to processes for preparing these intermediates.
BACKGROUND OF THE INVENTION
It is already known that 2-(2-hydroxyphenyl)-2-(methoxyimino)-N-methylacetamide (C) is obtained when methyl 2-(2-hydroxyphenyl)-2-(methoxyimino)-acetate (A) or 1-benzofuran-2,3-dione 3-(O-methyl oxime) (B) is reacted with methylamine (compare, for example, EP-A 398692 or WO 95-24396):
These processes have the disadvantage that the starting materials are difficult to obtain.
DETAILED DESCRIPTION OF THE INVENTION
It has now been found that 2-(2-hydroxyphenyl)-2-(alkoxyimino)-N-methylacetamide derivatives of the general formula (I)
in which
R represents substituted or unsubstituted alkyl, are obtained when
a) 2-(2-hydroxyphenyl)-2-(hydroxyimino)-N-methylacetamide of the formula (II)
is reacted with alkylating agents of the formula (III)
R—X (III)
in which
R is as defined above, and
X represents halogen, —O—CO—O—R, —O—SO
2
—R
1
or —O—SO
2
—O—R, where R is as defined above and R
1
represents alkyl or optionally alkyl-substituted phenyl,
if appropriate in the presence of a diluent and if appropriate in the presence of an acid acceptor, if appropriate in the presence of a phase-transfer catalyst, or when
b) 2-(2-hydroxyphenyl)-2-(methylimino)-N-methylacetamide of the formula (IV)
is reacted with alkoxyamines of the formula (V)
R—O—NH
2
(V)
in which
R is as defined above,
or an acid addition complex thereof,
if appropriate in the presence of a diluent and if appropriate in the presence of a buffer medium, or when
c) 2-(2-hydroxyphenyl)-2-(oxo)-N-methylacetamide of the formula (VI)
is reacted with alkoxyamines of the formula (V)
R—O—NH
2
(V)
in which
R is as defined above,
or an acid addition complex thereof,
if appropriate in the presence of a diluent and if appropriate in the presence of a buffer medium.
In the definition of R, the saturated hydrocarbon chains, such as alkyl, are in each case straight-chain or branched. In particular, alkyl represents C
1
-C
4
-alkyl, preferably methyl, ethyl, n- or i-propyl, n-, s- or i-butyl, n-pentyl or i-pentyl, in particular methyl, ethyl or n-propyl.
The preferred substituent for alkyl is halogen.
Halogen generally represents fluorine, chlorine, bromine or iodine, preferably fluorine, chlorine or bromine, in particular fluorine or chlorine.
Aryl represents aromatic, mono- or polycyclic hydrocarbon rings, such as, for example, phenyl, naphthyl, anthranyl, phenanthryl, preferably phenyl or naphthyl, in particular phenyl.
Suitable substituents for aryl are alkyl or halogen.
R represents in particular methyl, ethyl, fluoromethyl and difluoromethyl.
R particularly preferably represents methyl.
R
1
particularly preferably represents methyl or tolyl.
The abovementioned general or preferred radical definitions apply both to the end products of the formula (I) and, correspondingly, to the starting materials or intermediates required in each case for the preparation.
The particular radical definitions given for these radicals in the respective combinations or preferred combinations of radicals are, independently of the particular combination of radicals given, also replaced as desired by radical definitions of other preferred ranges.
If appropriate, the compounds according to the invention can be present as mixtures of different possible isomeric forms, in particular stereoisomers, such as, for example, E and Z. What is claimed are both the E and the Z isomers, and any desired mixtures of these isomers.
It is extremely surprising that the alkylation in the process a) according to the invention occurs selectively in high yield at the oxygen atom of the oxime group. In general, in the alkylation of oximes, mixtures of the O- and N-alkylation products are formed. A selective O-alkylation can otherwise only be realized with silver salts which are expensive or difficult to prepare (cf. H. Metzger in Houben-Weyl, Methoden der org. Chemie, Volume X/4, page 217 ff., 1968)
The process a) according to the invention has a number of advantages. Thus, 2-(2-hydroxyphenyl)-2-(alkoxyimino)-N-methylacetamide derivatives of the formula (I) can be obtained in high yields and purities from easily obtainable starting materials, under conditions which do not cause any technical problems at all.
It is extremely surprising that the selective exchange of the imino group in the process b) according to the invention occurs without any side reactions and under very simple conditions.
The process b) according to the invention has a number of advantages. Thus, 2-(2-hydroxyphenyl)-2-(alkoxyimino)-N-methylacetamide derivatives of the formula (I) can be obtained in high yields and purities from easily obtainable starting materials, under conditions which do not cause any technical problems at all.
It is extremely surprising that, in the process c) according to the invention, the derivatives of the formula (I) are obtained in high yields and high purity.
The process c) according to the invention has a number of advantages. Thus, 2-(2-hydroxyphenyl)-2-(alkoxyimino)-N-methylacetamide derivatives of the formula (I) can be obtained in high yields and purities from easily obtainable starting materials, under conditions which do not cause any technical problems at all.
The 2-(2-hydroxyphenyl)-2-(hydroxyimino)-N-methylacetamide of the formula (II) required as starting material for carrying out the process a) according to the invention has hitherto not been disclosed and, as novel chemical compound, also forms part of the subject-matter of the present application.
2-(2-Hydroxyphenyl)-2-(hydroxyimino)-N-methylacetamide of the formula (II) is obtained when
d) 2-(2-hydroxyphenyl)-2-(methylimino)-N-methylacetamide of the formula (I)
is reacted with hydroxylamine or an acid addition complex thereof,
if appropriate in the presence of a diluent and if appropriate in the presence of a buffer medium,
or when
e) 2-(2-hydroxyphenyl)-2-oxo-N-methylacetamide of the formula (VI)
is reacted with hydroxylamine or an acid addition complex thereof,
if appropriate in the presence of a diluent and if appropriate in the presence of a buffer medium.
It is extremely surprising that the selective exchange of the imino group by the process d) according to the invention proceeds under simple and mild conditions and without any side reactions.
The process d) according to the invention has a number of advantages. Thus, 2-(2-hydroxyphenyl)-2-(hydroxyimino)-N-methylacetamide of the formula (II) can be obtained in high yields and purities from easily obtainable starting materials, under conditions which do not cause any technical problems at all.
It is extremely surprising that the reaction with hydroxylamine by the process e) according to the invention takes place selectively at the keto group.
The process e) according to the invention has a number of advantages. Thus, 2-(2-hydroxyphenyl)-2-(hydroxyimino)-N-methylacetamide of the formula (II) can be obtained in high yields and purities from easily obtainable starting materials, under conditions which do not cause any technical problems at all.
The 2-(2-hydroxyphenyl)-2-(methylimino)-N-methylacetamide of the formula (IV) required as starting material for carrying out the processes b) and d) according to the invention has hitherto not been disclosed and, as novel chemical compound, also forms part of the subject-matter of the present application.
2-(2-Hydroxyphenyl)-2-(methylimino)-N-methylacetamide of the formula (IV)
is obtained when
f) an alkyl (2-hydroxyphenyl)-oxoacetate of the general formula (VII)
in which
A represents alkyl or optionally substituted aryl,
is reacted with methylamine, if appropriate in the presence of a diluent,
or when
g) 1-benzofuran-2,3-dione of the formula (VIII)
is reacted with methylamine, if appropriate in the presence of a diluent.
It is extremely surprising that, by the processes f)
Gallenkamp Bernd
Gayer Herbert
Hübsch Walter
Lantzsch Reinhard
Müh Thorsten
Bayer Aktiengesellschaft
Henderson Richard E. L.
Kumar Shailendra
LandOfFree
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