Organic compounds -- part of the class 532-570 series – Organic compounds – Sulfur containing
Reexamination Certificate
2000-10-10
2002-03-12
Vollano, Jean F. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Sulfur containing
C568S034000, C585S351000
Reexamination Certificate
active
06355841
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a process for the production of &bgr;-carotene, a carotenoid that is important in the fields of medicines, feed additives and food additives and also to an intermediate of &bgr;-carotene.
For the synthesis of &bgr;-carotene, which is a symmetric C40 compound, there have been known a method of coupling two C19 compounds and a C2 compound, and a method of coupling two C15 compounds and a C10 compound (e.g., Helv. Chim. Acta, Vol. 39, 249 (1956) or Pure & Appl. Chem., Vol. 63, 35 (1991)). However, these methods were not always satisfactory in that they required to synthesize two different compounds having different carbon numbers and molecular structures. Methods of coupling two C20 compounds as reported in Pure & Appl. Chem., Vol. 63, 35 (1991), Japanese Patent No.2506495 or JP8-311020(Laid-Open unexamined) have also been known, however, these methods are not always practical from an industrial point of view because of multistep reactions to obtain C20 compounds, instability of intermediates, low yield of coupling reaction of said two C20 compounds, or the like.
SUMMARY OF THE INVENTION
An object of the invention is to provide a method for producing &bgr;-carotene using a novel intermediate compound.
Further objects of the invention are to provide industrially advantageous two C20 compounds for producing the intermediate compound and methods for producing the two C20 compounds from an inexpensive C10 compound, linalool or geraniol in an industrially advantageous manner.
The present invention provides:
1. a process for producing a sulfone derivative of formula (1):
wherein
Ar represents an aryl group which may be substituted,
R represents a lower alkyl group and the wavy line depicted by
indicates a single bond and stereochemistry relating to a double bond bound therewith is E or Z or a mixture thereof,
which comprises reacting an aldehyde derivative of formula (2):
wherein
Ar, R and the wavy line respectively have the same meanings as defined above, with a phosphonium salt of formula (3):
wherein
Ar, R and the wavy line respectively have the same meanings as defined above, X represents a halogen atom or HSO
4
, and
Y means an lower alkyl group or an optionally substituted phenyl group, in the presence of a base or an epoxide;
2. a sulfone derivative of formula (1) as defined above; and
3. a process for producing &bgr;-carotene of formula (4):
wherein the wavy line represents the same as defined above,
which comprises reacting a sulfone derivative of formula (1) as defined above, with a base.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will be hereinafter explained in detail below.
Substituents R and Ar in the chemical formulae of (1) through (7) in the present specification will be explained first.
Examples of the lower alkyl group represented by R in the sulfone derivative (1), aldehyde derivative (2), phosphonium salt (3) and alcohol derivative (7) in the present invention include a (C1-C5) straight or branched chain alkyl group such as a methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl group, n-pentyl group, i-pentyl group, neo-pentyl group and the like. Preferred is a methyl group.
Examples of the aryl group which may be substituted represented by “Ar” include
a phenyl group and a naphthyl group, both of which may be substituted with at least one group selected from
a C1 to C6 alkyl group(e.g. a methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, i-butyl, t-butyl, n-pentyl, t-amyl, or n-hexyl group),
a C1 to C6 alkoxy group(e.g. a methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, s-butoxy, i-butoxy, t-butoxy, n-pentyloxy, t-amyloxy, or n-hexyloxy group),
a halogen atom and a nitro group.
Preferred Aryl Group is a Tolyl Group.
Specific examples of the optionally substituted aryl group include a phenyl, naphthyl, o-tolyl, m-tolyl, p-tolyl, o-methoxyphenyl, m-methoxyphenyl, p-methoxyphenyl, o-chlorophenyl, m-chlorophenyl, p-chlorophenyl, o-bromophenyl, m-bromophenyl, p-bromophenyl, o-iodophenyl, m-iodophenyl, p-iodophenyl, o-fluorophenyl, m-fluorophenyl, p-fluorophenyl, o-nitrophenyl, m-nitrophenyl and p-nitrophenyl group.
Next, a description will be made to the process for producing a sulfone derivative of formula (1) which comprises reacting an aldehyde derivative of formula (2) with a phosphonium salt of formula (3) in the presence of a base or an epoxide.
Specific examples of the aldehyde derivative of formula (2) include an aldehyde derivative of formula (2), wherein
Ar is a p-tolyl group and R is a methyl group, and
aldehyde derivatives of formula (2), wherein
Ar is a p-tolyl group and R represents any one of specific C2-C4 alkyl groups as described above. Further specific examples thereof include aldehyde derivatives of formula (2), wherein the p-tolyl group is replaced by other specific groups as described above for “Ar” in the above-described specific aldehyde derivatives.
The aldehyde derivative (2) can be obtained by a process as shown in Scheme 1.
In the phosphopnium salt of formula (3), a halogen atom represented by X include a chlorine atom, bromine atom and iodine atom.
Examples of the lower alkyl group represented by Y include a C1-C6 alkyl group such as a methl, ethyl, n-propyl, i-propyl, sec-butyl, n-butyl, i-butyl, n-pentyl, or the like.
Examples of the optionally substituted phenyl group represented by Y include
a phenyl group which may be substituted with a C1-C3 alkyl (e.g. a methyl, ethyl, n-propyl, or i-propyl group) or a C1-C3 alkoxy group (e.g. a methoxy, ethoxy, n-propoxy, or i-propoxy group).
Specific examples of a group of formula: PY
3
in the phosphonium salt of formula (3) include triethylphosphine, tripropylphosphine, tributylphosphine, tripentylphosphine, trihexylphosphine, triphenylphosphine, tri-(o-tolyl)phosphine and the like.
Specific examples of the phosphonium salt (3) include a phosphonium salt (3), wherein “Ar” and R have the same meaning as defined for specific examples of the aldehyde derivative of formula (2) and Y is a phenyl group and X is chlorine, and
further examples of compounds of formula (3), wherein Y represents any one of the groups as specified for Y above in place of the phenyl group above. In addition to these phosphonium salt (3), yet further examples thereof include phosphonium salts of formula (3), wherein X represents bromine, iodine or HSO
4
in place of chlorine in the specified compounds above, and the like.
The amount of the phosphonium salt (3) to be used is usually 0.5 to 2.0 moles, preferably, 0.8 to 1.2 per mole of the aldehyde derivative (2).
There is no particular limitation as to the base used in the above reaction of the aforementioned phosphonium salt (3) with the aldehyde derivative (2) as long as it does not adversely affect the reaction.
Examples of the base include an alkali metal alkoxide such as potassium methoxide, potassium ethoxide, potassium n-butoxide, potassium t-butoxide, sodium methoxide, sodium ethoxide, sodium n-butoxide, or sodium t-butoxide and an alkali metal hydroxide such as potassium hydroxide or sodium hydroxide. An epoxide such as an ethylene oxide or 1,2-butene oxide may be used instead of the base.
The amount of the base or epoxide to be used is usually 1 to 5 moles per mol the phosphonium salt of formula (3).
Reacting of an aldehyde derivative of formula (2) with a phosphonium salt of formula (3) in the presence of a base or an epoxide is usually conducted in an organic solvent.
Examples of the solvent include
a hydrocarbon solvent such as n-hexane, cyclohexane, n-pentane, n-heptane, toluene or xylene,
a halogenated hydrocarbon solvent such as chloroform, dichloromethane, 1,2-dichloroethane, monochlorobenzene, o-dichlorobenzene or &agr;, &agr;, &agr;-trifluorotoluene,
an aprotic polar solvent such as N,N-dimethylformamide, dimethylsulfoxide, acetonitrile, N,N-dimethylacetamide or hexamethylphosphoric triamide and
an ether solvent such as 1,4-dioxane, tetrahydrofuran or anisole.
The reaction may also be conducted in a two phase system of an organi
Konya Naoto
Seko Shinzo
Birch & Stewart Kolasch & Birch, LLP
Sumitomo Chemical Company Limited
Vollano Jean F.
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