Immobilized palladium complexes

Details Immobilized palladium complexes Immobilized palladium complexes

2001-05-21

2003-03-11

McKane, Joseph K. (Department: 1626)

Organic compounds -- part of the class 532-570 series

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

C548S112000

Reexamination Certificate

active

06531607

ABSTRACT:

The invention relates to immobilized palladium complexes, to a process for their preparation, to their use as catalysts and to a process for the preparation of arylamines using the immobilized palladium complexes.
Arylamines, especially substituted anilines, are of great industrial importance as precursors for dyestuffs, fine chemicals, pharmaceuticals and agrochemicals. Arylamines are generally prepared on the industrial scale by the nitration of an appropriate aromatic compound, followed by hydrogenation. As nitrations are carried out under drastic reaction conditions, a large number of complex substituted arylamines cannot be prepared satisfactorily in this way, if at all.
Arylamines can also be prepared by the ammonolysis of phenols and chlorobenzenes (K. Weissermel et al., Industrial Organic Chemistry, 1993, 2nd edition, VCH Verlagsgesellschaft, Weinheim, 370-373). Again, because of its drastic reaction conditions, this procedure is unsuitable for the preparation of substituted arylamines.
U.S. Pat. No. 5,576,460 describes a process for the preparation of arylamines by reacting metal amides, prepared in situ, with amines using palladium complexes carrying phosphine ligands. The disadvantage of this process is that the phosphine ligands required for this purpose are normally expensive, air-sensitive and difficult to handle. The palladium complexes produced therefrom in situ are also air-sensitive and susceptible to degradation reactions.
Nolan et al., Organic Letters Vol. 1, No. 8, 1999, 1307-1309, describe the preparation of arylamines using palladium catalysts carrying heterocyclic carbenes as ligands. In comparison with phosphine ligands, heterocyclic carbenes have a high thermal and chemical stability. However, one disadvantage of the palladium catalysts used by Nolan et al. is that they have to be removed from the reaction mixture when the reaction has ended, which is costly. Another disadvantage is that the catalyst cannot be recycled, i.e. re-used in another reaction.
Surprisingly, immobilized palladium complexes have now been found which are distinguished by their ease of preparation, their high thermal stability and their insensitivity to oxygen and moisture. The complexes according to the invention have a high activity and selectivity and can preferably be used as catalysts for the preparation of arylamines. When the reaction has ended, the catalysts can easily be separated from the reaction mixture and used in another reaction without loss of activity.
The complexes according to the invention are supported compounds of formula (I):
in which
X is halogen, trifluoromethanesulphonate, acetylacetonate or acetate,
L is a radical of the formula P(D)
3
, D being alkyl, cycloalkyl, aryl, aralkyl, alkylaryl or heteroaryl, or
a radical of the formula N(E)
2
, E being alkyl, cycloalkyl, aryl, aralkyl, alkylaryl or heteroaryl, or
a radical of formula (II):
in which
B
1
and B
2
are identical or different and are a radical to complete a heterocycle, especially
R
1
-R
4
are identical or different and are a divalent radical from the group comprising alkyl, cycloalkyl, aryl, aralkyl and alkylaryl, each of which is optionally substituted by COO—(C
1
-C
4
-alkyl), O(C
1
-C
4
-alkyl) or CONH
2
, and
A
1
-A
4
are identical or different and are hydrogen or a chemical bond from the group comprising —CONH—, —CO—O—OC—, —COO—, —O— and
via which the complex is bonded to the support, with the proviso that at least one A is other than hydrogen.
The terms used above are defined as follows:
“Halogen” denotes F, Cl, Br or I.
“Alkyl” denotes linear or branched —C
1
-C
12
-alkyl, for example methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, isoheptyl, 2-ethylhexyl or octyl.
“Cycloalkyl” denotes —C
3
-C
8
-cycloalkyl, for example cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl or cyclooctyl.
“Aryl” denotes —C
6
-C
14
-aryl, for example phenyl, naphthyl or biphenyl.
“Aralkyl” denotes —C
1
-C
12
-alkyl-C
6
-C
14
-aryl, the free valency being on the alkyl moiety, for example phenylmethyl, phenylethyl, naphthylmethyl, naphthylethyl, diphenylmethyl or triphenylmethyl.
“Alkylaryl” denotes —C
6
-C
14
-aryl-C
1
-C
12
-alkyl, the free valency being on the aryl moiety, for example tolyl, ethylphenyl, xylyl, methylnaphthyl or ethylnaphthyl.
“Heteroaryl” denotes unsaturated rings having 5 or 6 atoms and containing one or two oxygen atoms and sulphur atoms and/or one to four nitrogen atoms, with the proviso that the total number of heteroatoms is four or less, for example furan, thiophene, pyridine, pyrrole or imidazole, or bicyclic rings in which the 5- or 6-membered rings defined above are fused to a benzene or pyridine ring, for example purines, benzopyran or benzimidazole.
The complexes according to the invention are preferably supported compounds of formula (I) in which
X is halogen,
L is a radical of the formula P(D)
3
, D being a radical from the group comprising cyclohexyl, phenyl, naphthyl and tolyl, or a radical of formula (II):
in which
B
1
and B
2
are identical or different and are
R
1
-R
4
are identical or different and are a divalent radical from the group comprising alkyl, cycloalkyl, aryl, aralkyl and alkylaryl, each of which is optionally substituted by COO—(C
1
-C
4
-alkyl), O(C
1
-C
4
-alkyl) or CONH
2
, and
A
1
-A
4
are identical or different and are hydrogen or a chemical bond from the group comprising —CONH—, —CO—O—OC—, —COO—, —O— and
via which the complex is bonded to the support, with the proviso that at least one A is other than hydrogen and the support is selected from the group comprising inorganic supports and polymeric supports.
The complexes according to the invention are particularly preferably compounds of formula (I) in which
X is I,
L is
B
1
is
R
1
and R
3
are identical and are a divalent radical —(C
1
-C
6
-alkyl)-, preferably —CH
2
—,
R
2
and R
4
are identical and are a divalent radical —(C
1
-C
6
-alkyl)-, preferably —(CH
2
)
3
,
A
1
and A
3
are identical and are hydrogen, and
A
2
and A
4
are identical and are a chemical bond from the group comprising —CONH—, —CO—O—OC—, —COO—, —O— and
and the support is an inorganic support from the group comprising silica gel, magnesium oxide and aluminium oxide, or a polymeric support from the group comprising polyester, polyether, polyethylene, polypropylene and polystyrene.
Very particularly preferred supports are functionalized polystyrenes crosslinked with divinylbenzene, such as those conventionally used in solid phase peptide chemistry or for solid phase synthesis.
The complexes according to the invention can be prepared in situ or separately. This can be done by first fixing the ligands to the support. The fixed ligands can then be converted in situ or separately to the complexes according to the invention.
Another possibility for separate preparation is first to prepare the free complex from ligands and Pd compound and then to fix it to the support in order to prepare the complexes according to the invention.
The invention further relates to a process for the preparation of compounds of formula (I) which is characterized in that compounds of formulae (III) and (IV):
in which
B
1
and B
2
are identical or different and are a radical to complete a heterocycle, especially
R
1
-R
4
are identical or different and are a divalent radical from the group comprising alkyl, cycloalkyl, aryl, aralkyl and alkylaryl, each of which is optionally substituted by COO—(C
1
-C
4
-alkyl), O(C
1
-C
4
-alkyl) or CONH
2
,
G
1
-G
4
are identical or different and are hydrogen, COOH, CO—O—CO(C
1
-C
4
-alkyl), COO(C
1
-C
4
-alkyl), COCl, CO(C
1
-C
4
-alkyl), COH, NH
2
, NH(C
1
-C
4
-alkyl), OH, Si(O—C
1
-C
4
-alkyl)
3
or OCN, with the proviso that at least one G is other than hydrogen, and
Y is an anion from the group comprising Cl, Br, I, C
1
-C
4
-alkylsulphonate, C
6
-C
14
-arylsulphonate, hexafluorophosphate and tetrafluoroborate,
or compounds of formulae (III) and P(D)
3
, or compounds of formulae (III) and N(E)
2
, are reacted with Pd(II) compounds in the p

Affiliated with

Also associated with

Rating

Immobilized palladium complexes does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Immobilized palladium complexes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Immobilized palladium complexes will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3027439