Organic compounds -- part of the class 532-570 series – Organic compounds – Carbohydrates or derivatives
Reexamination Certificate
2000-01-05
2003-05-13
Fonda, Kathleen K. (Department: 1623)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carbohydrates or derivatives
C536S029130, C536S053000, C536S123130, C514S025000, C514S042000
Reexamination Certificate
active
06562954
ABSTRACT:
BACKGOUND OF THE INVENTION
The present invention relates to a method for producing an oligosaccharide. The present invention also relates to a novel oligosaccharide and a pharmaceutical composition containing it.
Keratan sulfate is a glycosaminoglycan comprising, as a basic structure, N-acetyl lactosamine in which the 6-position of the N-acetyl glucosamine residue is O-sulfated. It has been reported that some of degradation products of karatan sulfate, i.e., keratan sulfate oligosaccharides, have a pharmacological activity (see, for example, International Publication No. WO96/16973).
As a disaccharide structure derived from keratan sulfate, those shown in
FIG. 1
may be expected. However, searching of another keratan sulfate oligosaccharide having a pharmacological activity has been limited, because it has been difficult to obtain a keratan sulfate oligosaccharide as a disaccharide having a galactose residue at its reducing end (GlcNAc&bgr;1→3Gal where Gal represents galactose, GlcN represents glucosamine, and Ac represents an acetyl group) and having a sulfate group like keratan sulfate. For example, even by treating keratan sulfate with known endo-&bgr;-galactosidases, it is difficult to obtain a disaccharide having a galactose residue at its reducing end (GlcNAc&bgr;1→3Gal) with a sulfate group retained.
SUMMARY OF THE INVENTION
A first object of the present invention is to provide a method that makes it possible to easily produce a keratan sulfate disaccharide having a galactose residue at its reducing end.
A second object of the present invention is to provide a novel oligosaccharide having a pharmacological activity, and to provide it as a medicine.
The inventors of the present invention found that a disaccharide having a galactose residue at its reducing end could be obtained through glycosidic linkage formation by protecting hydroxyl groups and an amino group in glucosamine, and hydroxyl groups in galactose in a particular manner. Moreover, they also found that disaccharides in which hydroxyl groups at particular positions were sulfated had excellent pharmacological activities. The present invention has been accomplished based on these findings.
The present invention provides a method for producing an oligolsaccharide represented by the following general formula (3):
wherein R
10
and R
11
each independently represent a hydrogen atom or —SO
3
M where M represents a proton or a monovalent cation, Ac represents an acetyl group, R
12
represents a hydrogen atom, a 6-O-sulfated N-acetylglucosamine residue, an alkyl group, a glycerol residue, an O-alkylglycerol residue, an O-acylglycerol residue, a cholesterol residue, a cholestanyl group, a ceramide residue, a phospholipid residue, a biotin residue, or a peptide residue, and Z represents an oxygen atom or —NHCO—,
which method comprises at least a step of carrying out glycosidic linkage formation between a monosaccharide represented by the following general formula (1):
wherein R
1
and R
2
each independently represent an aralkyl group, R
3
represents an acyl group or a silyl group, R
4
represents a protective group for an amino group, and R
5
represents a leaving group, and
a monosaccharide represented by the following general formula (2):
wherein R
6
and R
8
each independently represent an aralkyl group, R
7
represents an acyl group or a silyl group, R
9
represents an aralkyl group, a 6-O-sulfated N-acetylglucosamine residue, an alkyl group, a glycerol residue, an O-alkylglycerol residue, an O-acylglycerol residue, a cholesterol residue, a cholestanyl group, a ceramide residue, a phospholipid residue, a biotin residue, or a peptide residue, and Z represents an oxygen atom or —NHCO— (this method is also referred to as the “production method of the present invention” hereinafter).
In the production method of the present invention, it is preferred that at least one of R
10
and R
11
represents —SO
3
M where M represents a proton or a monovalent cation, and the method comprises, after the step of carrying out the glycosidic linkage formation between the monosaccharide represented by the aforementioned general formula (1) and the monosaccharide represented by the aforementioned general formula (2), a step of substituting a hydrogen atom for at least one of R
3
and R
7
, and subsequently substituting —SO
3
M for the hydrogen atom.
In a preferred embodiment of the production method of the present invention, the aforementioned general formulae (1)-(3) are represented by the following formulae (4)-(6), respectively:
wherein Bn represents a benzyl group, R
13
represents an acetyl group or a levulinoyl group, and Phth represents a phthaloyl group, and X represents a halogen atom;
wherein Bn represents a benzyl group, R
14
represents a benzyl group, a 6-O-sulfated N-acetylglucosamine residue, an alkyl group, a glycerol residue, an O-alkylglycerol residue, an O-acylglycerol residue, a cholesterol residue, a cholestanyl group, a ceramide residue, a phospholipid residue, a biotin residue, or a peptide residue, Z represents an oxygen atom or —NHCO—, and Piv represents a pivaloyl group; and
wherein, Ac represents acetyl group, and M represents a proton or a monovalent cation, R
15
represents a hydrogen atom, a 6-O-sulfated N-acetylglucosamine residue, an alkyl group, a glycerol residue, an O-alkylglycerol residue, an O-acylglycerol residue, a cholesterol residue, a cholestanyl group, a ceramide residue, a phospholipid residue, a biotin residue, or a peptide residue, and Z represents an oxygen atom or —NHCO—.
In another preferred embodiment of the production method of the present invention, the aforementioned general formulae (1)-(3) are represented by the following formulae (7)-(9), respectively:
wherein, Bn represents a benzyl group, Lev represents a levulinoyl group, and Phth represents a phthaloyl group, and X represents a halogen atom;
wherein, Bn, R
14
and Z are as defined above, Ph represents a phenyl group, and Me represents a methyl group; and
wherein, R
15
and Z are as defined above, Ac represents an acetyl group, and M represents a proton or a monovalent cation.
In a further preferred embodiment of the production method of the present invention, the aforementioned general formulae (1)-(3) are represented by the following formulae (10)-(12), respectively:
wherein, Bn represents a benzyl group, Lev represents a levulinoyl group, and Phth represents a phthaloyl group, and X represents a halogen atom;
wherein, Bn, R
14
and Z are as defined above, Ph represents a phenyl group, and Me represents a methyl group; and
wherein, R
15
and Z are as defined above, Ac represents an acetyl group, and M represents a proton or a monovalent cation.
The present invention also provides an oligosaccharide represented by the following general formula (13):
wherein, R
16
and R
17
each independently represent a hydrogen atom or —SO
3
M where M represents a proton or a monovalent cation, Ac represents an acetyl group, R
18
represents a hydrogen atom, a 6-O-sulfated N-acetylglucosamine residue, an alkyl group, a glycerol residue, an O-alkylglycerol residue, an O-acylglycerol residue, a cholesterol residue, a cholestanyl group, a ceramide residue, a phospholipid residue, a biotin residue, or a peptide residue, and Z represents an oxygen atom or —NHCO—, provided that an oligosaccharide wherein both of R
16
and R
17
are hydrogen atoms, Z is an oxygen atom and R
18
is a hydrogen atom or a cholestanyl group, and an oligosaccharide wherein R
16
represents —SO
3
M where M represents a proton or a monovalent cation, Z is an oxygen atom and both of R
17
and R
18
are hydrogen atoms are excluded (The oligosaccharide is also referred to as the “oligosaccharide of the present invention” hereinafter).
In a preferred embodiment of the oligosaccharide of the present invention, each of R
16
and R
17
is —SO
3
M where M represents a proton or a monovalent cation.
In another preferred embodiment of the oligosaccharide of the present invention, R
16
is a hydrogen atom, and R
17
is —SO
3
M where M represents a
Hori Yusuke
Iida Masami
Matsuzaki Yuji
Miyauchi Satoshi
Mochizuki Hideo
Fonda Kathleen K.
Knobbe Martens Olson & Bear LLP
Seikagaku Corporation
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