Process for producing 4-alkoxycarbonyl-2-oxazolidinone compound

Details Process for producing 4-alkoxycarbonyl-2-oxazolidinone compound Process for producing 4-alkoxycarbonyl-2-oxazolidinone compound

2000-01-10

2002-07-02

Higel, Floyd D. (Department: 1626)

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

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

Reexamination Certificate

active

06414160

ABSTRACT:

TECHNICAL FIELD
This invention relates to a process for producing a 4-alkoxycarbonyl-2-oxazolidinone compound which is useful as synthetic starting materials or intermediates of pharmaceuticals and agricultural chemicals.
4-Alkoxycarbonyl-2-oxazolidinone compound can be easily led to a &bgr;-hydroxy-&agr;-amino acid compound which is useful as pharmaceuticals, or pharmaceutical intermediates or starting materials in accordance with the method described in, for example, Journal of American Chemical Society, 118, pp. 3584-3590 (1996) by subjecting to alkali hydrolysis using an aqueous potassium hydroxide solution.
BACKGROUND ART
As the conventional method for preparing 4-alkoxycarbonyl-2-oxazolidinone compound, the following methods have been known.
{circumflex over (1)}: In Nihon Kagakukai Zasshi, vol. 82, p. 1075, (1961), there is disclosed a method in which phosgene is acted on D,L-threonine in the presence of sodium hydroxide, and esterifying with methanol and hydrochloric acid to obtain 5-methyl-4-methoxycarbonyl-2-oxazoline. This method is not industrially sufficient method in the point of using &bgr;-hydroxy-&agr;-amino acid compound which is difficultly obtained as a starting material.
{circumflex over (2)}: In Nihon Kagakukai Zasshi, vol. 82, p. 1075, (1961), there is disclosed a method in which N-Cbz-D,L-arothreonine is subjected to ring opening in the presence of sodium hydroxide, and esterifying with methanol and hydrochloric acid to obtain 5-methyl-4-methoxycarbonyl-2-oxazolidinone. This method is also not industrially sufficient method in the point of using, as a starting material, &bgr;-hydroxy-&agr;-amino acid compound the starting material of which is difficultly obtained.
{circumflex over (3)}: In Journal of Organic Chemistry, vol. 44, p. 3967, (1979), there is disclosed a method in which N-carbobenzyloxyglycine ethyl ester is reacted with benzaldehyde in the presence of lithium diisopropylamide to obtain 5-phenyl-4-methoxycarbonyl-2-oxazolidinone. However, this method is not industrially satisfied preparation method in the point that lithium diisopropylamide handling of which is difficult must be used.
{circumflex over (4)}: In Tetrahedron Letters, vol. 29, p. 2069 (1988), there is disclosed a method of obtaining 3-methyl-5-(1-methyl-3-pentenyl)-4-methoxycarbonyl-2-oxazolidinone by reacting 3-(1-methyl-3-pentenyl)-2,3-epoxy-1-propanol and methyl iso-cyanate to obtain 4-hydroxymethyloxazolidine and oxidizing the resulting compound with a chromium compound and esterifying with diazomethane. However, the method is not industrially sufficient method in the points that the steps are long and a chromium compound or diazomethane which is difficultly used industrially must be used.
Accordingly, in the above-mentioned conventionally known methods {circumflex over (1)}, {circumflex over (2)}, {circumflex over (3)} and {circumflex over (4)}, there are problems that the starting materials are difficultly obtained, a starting material which is difficultly used for industrial purpose must be used, the steps are long and yield is low, so that a novel preparation method of 4-alkoxycarbonyl-2-oxazolidinone compound which can overcome these problems has been desired.
An object of the present invention is to provide a preparation method of a 4-alkoxycarbony-2-oxazolidinon compound which is available as a synthetic starting material or an intermediate of medicine or agricultural chemicals.
DISCLOSURE OF THE INVENTION
The present inventors have investigated to solve the above-mentioned problems and as a result, they have found that by reacting 5-alkoxy-2(3H)oxazolone compound which has not yet been described in the references and an aldehyde compound in the presence of a Lewis acid catalyst, a 4-alkoxycarbonyl-2-oxazolidinone compound can be obtained easily with high yield to accomplish the present invention. That is, the present invention is as mentioned below.
That is, the present invention related to a process for producing a 4-alkoxycarbonyl-2-oxazolidinone compound represented by the formula (III):
wherein R
1
represents a hydrogen atom, a C
1
to C
10
alkyl group which may be substituted, a C
3
to C
10
cycloalkyl group which may be substituted, a C
2
to C
10
alkenyl group which may be substituted or a phenyl group which may be substituted, R
2
represents a hydrogen atom, a C
1
to C
10
alkyl group which may be substituted, a phenyl group which may be substituted or a C
2
to C
10
alkenyl group which is not substituted, R
3
represents a C
1
to C
10
alkyl group which may be substituted, a C
3
to C
10
cycloalkyl group which may be substituted,o a C
2
to C
10
alkenyl group which may be substituted (provided that a 2-alkenyl group is excluded), or a phenyl group which may be substituted, and R
4
represents a hydrogen atom, a C
1
to C
20
alkyl group which may be substituted, a C
2
to C
20
alkenyl group which may be substituted, a C
3
to C
10
cycloalkyl group which may be substituted, a C
2
to C
20
alkynyl group which may be substituted, a C
6
to C
20
aryl group which may be substituted, a 5- or 6-membered heteroaromatic ring group having 1 or 2 hetero atoms selected from N, O and S which may be substituted, a C
1
to C
6
alkoxycarbonyl group which
may be substituted, an acetyl group or a benzoyl group, which comprises reacting a 5-alkoxy-2(3H)oxazolone compound represented by the formula (I):
wherein R
1
, R
2
and R
3
have the same meanings as defined above,
and an aldehyde compound represented by the formula (II):
R
4
CHO  (II)
wherein R
4
has the same meaning as defined above, in the presence of a Lewis acid catalyst to obtain the title compound.
BEST MODE FOR CARRYING OUT THE INVENTION
In the following, the present invention is explained in detail.
The process of the present invention can be shown, for example by the following reaction formula (I):
wherein R
1
, R
2
, R
3
and R
4
have the same meanings as defined above.
In the present invention, R
1
in the compound (I) represented by the formula (I) represents a hydrogen atom, a C
1
to C
10
alkyl group which may be substituted, a C
3
to C
10
cycloalkyl group which may be substituted or a C
2
to C
10
alkenyl group which may be substituted or a phenyl group which may be substituted.
“The C
1
to C
10
alkyl group which may be substituted” represented by R
1
means (1) “a C
1
to C
10
alkyl group having no substituent” or (2) “a C
1
to C
10
alkyl group having a substituent(s)”.
As “the C
1
to C
10
alkyl group having no substituent” of (1), there may be mentioned, for example, a straight or branched C
1
to C
10
alkyl group such as a methyl group, an ethyl group, a propyl group (including an isomer), a butyl group (including isomers thereof), a pentyl group (including isomers thereof), a hexyl group (including isomers thereof), a heptyl group (including isomers thereof), an octyl group (including isomers thereof), a nonyl group (including isomers thereof) or a decyl group (including isomers thereof), etc.
As the substituent for “the C
1
to C
10
alkyl group having a substituent(s)”, there may be mentioned, for example, a cyano group, a benzyloxy group, a phthalimino group, an acylamino group, an alkoxycarbonyl group having a straight or branched C
1
to C
6
alkyl group portion, a trialkylsilyloxy group having the same or different straight or branched C
1
to C
6
alkyl group portion, a halogen atom, an aryl group which may be substituted, “a 5- or 6-membered heteroaromatic ring group (hereinafter also referred to as “a heteroaromatic ring group”) containing 1 or 2 hetero atoms selected from N, O and S”, or a C
1
to C
10
alkoxy group which may be substituted. Incidentally, the number of the substituent(s) and the position thereof is not limited.
“The aryl group which may be substituted” as the substituent for “the C
1
to C
10
alkyl group having a substituent(s)” of (2) means (2-1) “an aryl group having no substituent” or (2-2) “an aryl group having a substituent(s)”.
As “the aryl group having no substituent” of (2-1), there may be mentioned, for example, a phenyl gro

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