Method of producing compound including isomerizing α,β-unsaturated ketone

Abstract

To provide a method of isomerizing α,β-unsaturated ketone for achieving a reduced reaction time and an enhanced reaction yield.SOLUTION: The present invention provides a method for producing a compound represented by the general formula (I) in the figure, the method comprising isomerizing a compound represented by the general formula (II) in the figure in the presence of molecular hydrogen and / or a hydrogen source, a platinum group metal catalyst, and a simple substance of Group 16 elements (excluding oxygen) or a compound thereof.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing a compound, which includes an isomerization step of an α,β-unsaturated ketone. [Background technology]

[0002] Alkyl (3-oxo-2-alkylcycloalkyl) acetates, particularly methyl dihydrojasmonate (MDJ), are useful fragrance materials with floral and jasmine-like aromas.

[0003] [ka]

[0004] For example, it has already been reported that MDJ can be obtained by an aldol reaction of cyclopentanone (1) and pentanal (2), as well as a dehydration and isomerization reaction to obtain compound (3), which is then reacted with dimethylmalonic acid ester (Patent Document 1).

[0005] [ka]

[0006] The aforementioned aldol reaction, as well as the dehydration and isomerization reactions, proceed specifically as follows.

[0007] [ka]

[0008] The aldol reaction of cyclopentanone (1) and pentanal (2) yields a keto alcohol (4). Dehydration of this keto alcohol (4) yields an α,β-unsaturated ketone compound (5). Isomerization of this α,β-unsaturated ketone compound (5) yields an α,β-unsaturated ketone compound (3).

[0009] For example, Patent Document 1 discloses a method for producing 2-alkyl-2-cycloalkene-1-one, which involves dehydrating and isomerizing 2-(1-hydroxyalkyl)-cycloalkane-1-one in the presence of an acid and a platinum group metal catalyst.

[0010] [ka]

[0011] Furthermore, Patent Document 2 discloses a manufacturing method in which an isomerization is carried out in the presence of a catalyst system comprising i) a metal selected from palladium (Pd) or platinum (Pt) and ii) molecular hydrogen or a hydrogen source.

[0012] [ka]

[0013] Furthermore, Patent Document 3 discloses a method for isomerizing olefins in a double bond isomerization reaction using a platinum group metal catalyst and hydrogen, by using a platinum group catalyst that has been treated with an organosulfur compound before being charged into the reactor. [Prior art documents] [Patent Documents]

[0014] [Patent Document 1] Japanese Patent Publication No. 2009-269910 [Patent Document 2] Japanese Patent Publication No. 2016-509991 [Patent Document 3] Japanese Patent Application Publication No. 7-69938 [Overview of the project] [Problems that the invention aims to solve]

[0015] However, the methods described in Patent Documents 1 and 2 have a problem in that, in the isomerization of the double bond, the presence of molecular hydrogen or a hydrogen source results in the formation of a compound with a hydrogenated double bond as a by-product, reducing the selectivity of the isomerization reaction. Furthermore, reducing the amount of hydrogen to suppress hydrogenation reduces the reactivity of the isomerization reaction. While it is possible to achieve both reactivity and selectivity of the isomerization reaction by increasing the amount of platinum group catalyst, this presents the problem of increased manufacturing costs.

[0016] Furthermore, the method described in Patent Document 3 targets olefins and differs from the method of isomerizing compounds obtained by dehydrating keto alcohols. In addition, this method has the drawback of low yield.

[0017] Therefore, the present invention aims to provide a method for isomerizing α,β-unsaturated ketones that achieves reduced reaction time and improved reaction yield. [Means for solving the problem]

[0018] The inventors of the present invention have surprisingly discovered that when sulfur, a Group 16 element (excluding oxygen), is present during the isomerization of α,β-unsaturated ketones using a platinum group catalyst, the reaction time is shortened and the reaction yield is improved. Based on this finding, the inventors of the present invention have completed the method of the present invention.

[0019] In other words, the present invention is This is a method for producing a compound represented by the following general formula (I), comprising the step of isomerizing a compound represented by the following general formula (II) in the presence of molecular hydrogen and / or a hydrogen source, a platinum group metal catalyst, and a group 16 element (excluding oxygen) in its elemental form or a compound thereof.

[0020] [ka]

[0021] During the ceremony, R 1 , R 2 , and R 4represents, simultaneously or independently, a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms, R 3 represents a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms, or alternatively, R 1 and R 4 represent, simultaneously or independently, a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms, R 2 and R 3 together represent an alkanediyl group having 2 to 9 carbon atoms, or an alkanediyl group having 2 to 9 carbon atoms substituted with 1 to 2 alkyl groups having 1 to 5 carbon atoms.

Advantages of the Invention

[0022] The method of the present invention can achieve shortening of the reaction time and improvement of the reaction yield in the isomerization method of α,β-unsaturated ketones. Furthermore, reduction of the amount of the platinum group metal catalyst is also possible.

Embodiments for Carrying Out the Invention

[0023] The present invention is, as described above, a method for producing a compound represented by the following general formula (I), including a step of isomerizing a compound represented by the following general formula (II) in the presence of molecular hydrogen and / or a hydrogen source, a platinum group metal catalyst, and a Group 16 element (excluding oxygen) alone or a compound thereof.

[0024]

Chemical Formula

[0025] In the formula, R 1 、R 2 、and R 4R represents, simultaneously or independently, a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms. 3 This represents a linear or branched alkyl group with 1 to 8 carbon atoms, or a linear or branched alkenyl group with 2 to 8 carbon atoms, or R 1 and R 4 This simultaneously or independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms. R 2 and R 3 Together, these represent either an alkanediyl group with 2 to 9 carbon atoms, or an alkanediyl group with 2 to 9 carbon atoms substituted with 1 to 2 alkyl groups with 1 to 5 carbon atoms.

[0026] Furthermore, the present invention is a method for producing a compound represented by general formula (I), further comprising the step of dehydrating a compound represented by general formula (III) in the presence of an acid to obtain a compound represented by general formula (II).

[0027] [ka]

[0028] During the ceremony, R 1 , R 2 , and R 4 This simultaneously or independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms. R 3 This represents a linear or branched alkyl group with 1 to 8 carbon atoms, or a linear or branched alkenyl group with 2 to 8 carbon atoms. or R 1 and R 4 This simultaneously or independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms. R2 and R 3 Together, these represent either an alkanediyl group with 2 to 9 carbon atoms, or an alkanediyl group with 2 to 9 carbon atoms substituted with 1 to 2 alkyl groups with 1 to 5 carbon atoms.

[0029] Furthermore, the present invention is a method for producing a compound of formula (VII), comprising the following steps 1 and 2. Step 1: A step of dehydrating and isomerizing a compound represented by the following general formula (IV) in the presence of molecular hydrogen and / or a hydrogen source, an acid, a platinum group metal catalyst, and a group 16 element (excluding oxygen) or a compound thereof, to obtain a compound represented by the following general formula (V). Step 2: A step to obtain a compound represented by general formula (VII) by reacting the compound represented by general formula (V) obtained in Step 1 with a malonic acid diester represented by general formula (VI) below, and then reacting it with water.

[0030] [ka]

[0031] During the ceremony, R 1 and R 4 This simultaneously or independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms. R 2 'and R 3 ' together represents an alkanediyl group with 2 to 9 carbon atoms, or an alkanediyl group with 2 to 9 carbon atoms substituted with 1 to 2 alkyl groups with 1 to 5 carbon atoms. R 7 represents an alkyl group with 1 to 3 carbon atoms, and the two R's 7 They may be the same or different.

[0032] In this specification, "linear or branched alkyl groups having 1 to 8 carbon atoms" refers to, for example, methyl, ethyl, n-propyl, isopropyl, 2-methylpropyl, n-butyl, i-butyl, sec-butyl, t-butyl, n-pentyl, i-pentyl group, sec-pentyl group, t-pentyl group, 2-methylbutyl group, n-hexyl, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group, 1-ethylbutyl group, 2-ethylbutyl group, 3-ethylbutyl group, and 1,1-dimethylbutyl group. Examples include 2,2-dimethylbutyl group, 3,3-dimethylbutyl group, 1-ethyl-1-methylpropyl group, n-heptyl, 1-methylhexyl group, 2-methylhexyl group, 3-methylhexyl group, 4-methylhexyl group, 5-methylhexyl group, 1-ethylpentyl group, 2-ethylpentyl group, 3-ethylpentyl group, 4-ethylpentyl group, 1,1-dimethylpentyl group, 2,2-dimethylpentyl group, 3,3-dimethylpentyl group, 4,4-dimethylpentyl group, 1-propylbutyl group, and n-octyl. Examples of "linear alkyl groups with 1 to 8 carbon atoms" include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, and n-octyl. "Branched C1-C8 alkyl groups" include, for example, isopropyl, i-butyl, sec-butyl, i-pentyl group, sec-pentyl group, t-pentyl group, 2-methylpropyl, 2-methylbutyl group, t-butyl, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group, 1-ethylbutyl group, 2-ethylbutyl group, 3-ethylbutyl group, 1,1-dimethylbutyl group, 2,2-dimethylbutyl group, 3,3- Examples include dimethylbutyl group, 1-ethyl-1-methylpropyl group, 1-methylhexyl group, 2-methylhexyl group, 3-methylhexyl group, 4-methylhexyl group, 5-methylhexyl group, 1-ethylpentyl group, 2-ethylpentyl group, 3-ethylpentyl group, 4-ethylpentyl group, 1,1-dimethylpentyl group, 2,2-dimethylpentyl group, 3,3-dimethylpentyl group, 4,4-dimethylpentyl group, and 1-propylbutyl group.In "linear or branched alkyl groups having 1 to 8 carbon atoms," the "alkyl groups having 1 to 8 carbon atoms" are preferably alkyl groups having 1 to 5 carbon atoms, and more preferably alkyl groups having 1 to 3 carbon atoms.

[0033] In this specification, "C1-C5 alkyl group" refers to, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, and pentyl alkyl groups. "C1-C5 alkyl group" is preferably a C1-C3 alkyl group, and more preferably a C1-C2 alkyl group.

[0034] In this specification, "alkyl groups having 1 to 3 carbon atoms" include, for example, methyl, ethyl, n-propyl, and isopropyl. C1-2 alkyl groups are preferred over C3 alkyl groups.

[0035] In this specification, "linear or branched alkenyl groups having 2 to 8 carbon atoms" include, for example, vinyl, allyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, 5-hexenyl, etc. The "linear or branched alkenyl groups having 2 to 8 carbon atoms" are preferably alkenyl groups having 2 to 6 carbon atoms, and more preferably alkenyl groups having 2 to 4 carbon atoms.

[0036] In this specification, "C2-C9 alkanediyl group" refers to linear alkylene groups having 2-9 carbon atoms, such as ethylene, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, and nonane-1,9-diyl group. "C2-C9 alkanediyl group" is preferably a C2-C7 alkanediyl group, and more preferably a C2-C5 alkanediyl group.

[0037] In this specification, "a C2-C9 alkanediyl group substituted with one or two C1-C5 alkyl groups" includes, for example, ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane-2,4-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, and 2-methylbutane-1,4-diyl group. "Alkanediyl groups having 2 to 9 carbon atoms substituted with 1 to 2 alkyl groups having 1 to 5 carbon atoms" is more preferably alkanediyl groups having 2 to 7 carbon atoms substituted with 1 to 2 alkyl groups having 1 to 5 carbon atoms, more preferably alkanediyl groups having 2 to 7 carbon atoms substituted with 1 to 2 alkyl groups having 1 to 3 carbon atoms, and more preferably alkanediyl groups having 2 to 5 carbon atoms substituted with 1 to 2 alkyl groups having 1 to 3 carbon atoms.

[0038] <Compounds represented by general formula (II) and compounds represented by general formula (I)> In the method for producing the compound represented by general formula (I) of the present invention (hereinafter sometimes referred to as "compound of formula (I)" or "compound (I)"), a compound represented by general formula (II) (hereinafter sometimes referred to as "compound of formula (II)" or "compound (II)") is used as a raw material.

[0039] [ka]

[0040] In equations (I) and (II) above, R 1 , R 2 , and R 4 This simultaneously or independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms. R 3 This represents a linear or branched alkyl group with 1 to 8 carbon atoms, or a linear or branched alkenyl group with 2 to 8 carbon atoms. or R 1 and R4 This simultaneously or independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms. R 2 and R 3 Together, these represent either an alkanediyl group with 2 to 9 carbon atoms, or an alkanediyl group with 2 to 9 carbon atoms substituted with 1 to 2 alkyl groups with 1 to 5 carbon atoms.

[0041] In equations (I) and (II) above, R 1 , R 2 , and R 4 This simultaneously or independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, or a linear or branched alkenyl group having 2 to 6 carbon atoms. R 3 This represents a linear or branched alkyl group with 1 to 6 carbon atoms, or a linear or branched alkenyl group with 2 to 6 carbon atoms. or R 1 and R 4 This simultaneously or independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, or a linear or branched alkenyl group having 2 to 6 carbon atoms. R 2 and R 3 It is preferable that together they represent an alkanediyl group having 2 to 7 carbon atoms, or an alkanediyl group having 2 to 7 carbon atoms substituted with 1 to 2 alkyl groups having 1 to 5 carbon atoms.

[0042] In equations (I) and (II) above, R 1 The group is preferably an alkyl group having 1 to 4 carbon atoms, and more preferably an n-butyl group.

[0043] In equations (I) and (II) above, R 4 The element is preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a hydrogen atom.

[0044] In equations (I) and (II) above, R 2 and R 3 Together, these are preferably alkanediyl groups having 2 to 9 carbon atoms, more preferably alkanediyl groups having 2 to 4 carbon atoms, and even more preferably alkanediyl groups having 2 carbon atoms.

[0045] In equations (I) and (II) above, R 1 is an n-butyl group, and R 2 and R 3 Together, these represent a carbon-2 alkanediyl group, R 4 It is even more preferable that it be a hydrogen atom.

[0046] Specific examples of compound (I) include 2-propyl-2-cyclopenten-1-one, 2-butyl-2-cyclopenten-1-one, 2-pentyl-2-cyclopenten-1-one, 2-hexyl-2-cyclopenten-1-one, 2-(1-methylbutyl)-2-cyclopenten-1-one, 2-(2-methylbutyl)-2-cyclopenten-1-one, 2-cyclopentyl-2-cyclopenten-1-one, and 2-cyclohexyl-2-cyclopenten-1 Examples include -one, 2-propyl-2-cyclohexen-1-one, 2-butyl-2-cyclohexen-1-one, 2-pentyl-2-cyclohexen-1-one, 2-hexyl-2-cyclohexen-1-one, 2-(1-methylbutyl)-2-cyclohexen-1-one, 2-(2-methylbutyl)-2-cyclohexen-1-one, 2-cyclopentyl-2-cyclohexen-1-one, and 2-cyclohexyl-2-cyclohexen-1-one. Among these, 2-propyl-2-cyclopenten-1-one, 2-butyl-2-cyclopenten-1-one, 2-pentyl-2-cyclopenten-1-one, and 2-hexyl-2-cyclopenten-1-one are preferred, and 2-pentyl-2-cyclopenten-1-one is particularly preferred.

[0047] Specific examples of compound (II) include 2-propyridenecyclopentan-1-one, 2-butylidenecyclopentan-1-one, 2-pentylidenecyclopentan-1-one, 2-hexylidenecyclopentan-1-one, 2-cyclopentylidenecyclopentan-1-one, 2-cyclohexylidenecyclopentan-1-one, 2-propyridenecyclohexane-1-one, 2-butylidenecyclohexane-1-one, 2-pentylidenecyclohexane-1-one, 2-hexylidenecyclohexane-1-one, 2-cyclopentylidenecyclohexane-1-one, and 2-cyclohexylidenecyclohexane-1-one. Among these, 2-propyridenecyclopentan-1-one, 2-butylidenecyclopentan-1-one, 2-pentylidenecyclopentan-1-one, and 2-hexylidenecyclopentan-1-one are preferred, with 2-pentylidenecyclopentan-1-one being particularly preferred.

[0048] <Compounds represented by general formula (III)> In the method for producing the compound represented by general formula (I) of the present invention (hereinafter sometimes referred to as "compound of formula (I)" or "compound (I)"), a compound represented by general formula (III) (hereinafter sometimes referred to as "compound of formula (III)" or "compound (III)") is used as a raw material.

[0049] [ka]

[0050] In the above formula (III), R 1 , R 2 and R 4 This simultaneously or independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms. R 3 This represents a linear or branched alkyl group with 1 to 8 carbon atoms, or a linear or branched alkenyl group with 2 to 8 carbon atoms. or R1 and R 4 This simultaneously or independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms. R 2 and R 3 Together, these represent either an alkanediyl group with 2 to 9 carbon atoms, or an alkanediyl group with 2 to 9 carbon atoms substituted with 1 to 2 alkyl groups with 1 to 5 carbon atoms.

[0051] In the above formula (III), R 1 , R 2 and R 4 This simultaneously or independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, or a linear or branched alkenyl group having 2 to 6 carbon atoms. R 3 This represents a linear or branched alkyl group with 1 to 8 carbon atoms, or a linear or branched alkenyl group with 2 to 8 carbon atoms. or R 1 and R 4 This simultaneously or independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, or a linear or branched alkenyl group having 2 to 6 carbon atoms. R 2 and R 3 It is preferable that together they represent an alkanediyl group having 2 to 7 carbon atoms, or an alkanediyl group having 2 to 7 carbon atoms substituted with 1 to 2 alkyl groups having 1 to 5 carbon atoms.

[0052] In the above formula (III), R 1 and R 4 This simultaneously or independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms. R 2 and R 3 It is more preferable that these elements together represent an alkanediyl group with 2 to 9 carbon atoms.

[0053] In the above formula (III), R 1 The group is preferably an alkyl group having 1 to 4 carbon atoms, and more preferably an n-butyl group.

[0054] In the above formula (III), R 4 The element is preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a hydrogen atom. In the above formula (III), R 2 and R 3 Together, these are preferably alkanediyl groups having 2 to 9 carbon atoms, more preferably alkanediyl groups having 2 to 4 carbon atoms, and even more preferably alkanediyl groups having 2 carbon atoms.

[0055] In the above formula (III), R 1 is an n-butyl group, and R 2 and R 3 Together, these represent a carbon-2 alkanediyl group, R 4 It is even more preferable that it be a hydrogen atom.

[0056] Specific examples of compound (III) include 2-(1-hydroxypropyl)-cyclopentanone, 2-(1-hydroxybutyl)-cyclopentanone, 2-(1-hydroxypentyl)-cyclopentan-1-one, 2-(1-hydroxyhexyl)-cyclopentanone, 2-(1-hydroxy-1-methylbutyl)-cyclopentanone, 2-(1-hydroxy-2-methylbutyl)-cyclopentanone, 2-(1-hydroxycyclopentyl)-cyclopentanone, and 2-(1-hydroxycyclohexyl)-cyclo Examples include lopentanone, 2-(1-hydroxypropyl)-cyclohexanone, 2-(1-hydroxybutyl)-cyclohexanone, 2-(1-hydroxypentyl)-cyclohexanone, 2-(1-hydroxyhexyl)-cyclohexanone, 2-(1-hydroxy-1-methylbutyl)-cyclohexanone, 2-(1-hydroxy-2-methylbutyl)-cyclohexanone, 2-(1-hydroxycyclopentyl)-cyclohexanone, and 2-(1-hydroxycyclohexyl)-cyclohexanone. Among these, 2-(1-hydroxypropyl)-cyclopentanone, 2-(1-hydroxybutyl)-cyclopentanone, 2-(1-hydroxypentyl)-cyclopentan-1-one, and 2-(1-hydroxyhexyl)-cyclopentanone are preferred, with 2-(1-hydroxypentyl)-cyclopentan-1-one being particularly preferred.

[0057] <Compounds represented by general formula (IV), compounds represented by general formula (V), compounds represented by general formula (VI), and compounds represented by general formula (VII)> In the method for producing the compound represented by general formula (VII) of the present invention (hereinafter sometimes referred to as "compound of formula (VII)" or "compound (VII)"), the following are used as raw materials: the compound represented by general formula (IV) (hereinafter sometimes referred to as "compound of formula (IV)" or "compound (IV)"), the compound represented by general formula (V) (hereinafter sometimes referred to as "compound of formula (V)" or "compound (V)"), and the compound represented by general formula (VI) (hereinafter sometimes referred to as "compound of formula (VI)" or "compound (VI)").

[0058] [Chemistry]

[0059] In the above formulas (IV), (V), (VI), and (VII), R 1 and R 4 each represents, simultaneously or independently, a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms. R 2 ’ and R 3 ’ together represent an alkanediyl group having 2 to 9 carbon atoms or an alkanediyl group having 2 to 9 carbon atoms substituted with 1 to 2 alkyl groups having 1 to 5 carbon atoms. R 7 represents an alkyl group having 1 to 3 carbon atoms, and the two R 7 may be the same or different.

[0060] In the above formulas (IV), (V), (VI), and (VII), R 1 and R 4 each represents, simultaneously or independently, a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, or a linear or branched alkenyl group having 2 to 6 carbon atoms. R 2 ’ and R 3 ’ together represent an alkanediyl group having 2 to 7 carbon atoms or an alkanediyl group having 2 to 7 carbon atoms substituted with 1 to 2 alkyl groups having 1 to 5 carbon atoms. R 7 represents an alkyl group having 1 to 3 carbon atoms, and preferably the two R 7 are the same or different.

[0061] In the above formulas (IV), (V), (VI), and (VII), R 1 is preferably an alkyl group having 1 to 4 carbon atoms, more preferably an n-butyl group.

[0062] In the above formulas (IV), (V), (VI), and (VII), R 4 is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom.

[0063] In the above formulas (IV), (V), (VI), and (VII), R 2 ’ and R 3 ’ together preferably form an alkanediyl group having 2 to 9 carbon atoms, more preferably an alkanediyl group having 2 to 4 carbon atoms, and still more preferably an alkanediyl group having 2 carbon atoms.

[0064] In the above formulas (IV), (V), (VI), and (VII), R 7 is preferably a methyl group.

[0065] In the above formulas (IV), (V), (VI), and (VII), R 1 is an n-butyl group, R 2 ’ and R 3 ’ together represent an alkanediyl group having 2 carbon atoms, R 4 is a hydrogen atom, and R 7 is preferably a methyl group.

[0066] Specific examples of compound (IV) include 2-(1-hydroxypropyl)-cyclopentanone, 2-(1-hydroxybutyl)-cyclopentanone, 2-(1-hydroxypentyl)-cyclopentanone, 2-(1-hydroxyhexyl)-cyclopentanone, 2-(1-hydroxy-1-methylbutyl)-cyclopentanone, 2-(1-hydroxy-2-methylbutyl)-cyclopentanone, 2-(1-hydroxycyclopentyl)-cyclopentanone, and 2-(1-hydroxycyclohexyl)-cyclo Examples include pentanone, 2-(1-hydroxypropyl)-cyclohexanone, 2-(1-hydroxybutyl)-cyclohexanone, 2-(1-hydroxypentyl)-cyclohexanone, 2-(1-hydroxyhexyl)-cyclohexanone, 2-(1-hydroxy-1-methylbutyl)-cyclohexanone, 2-(1-hydroxy-2-methylbutyl)-cyclohexanone, 2-(1-hydroxycyclopentyl)-cyclohexanone, and 2-(1-hydroxycyclohexyl)-cyclohexanone. Among these, 2-(1-hydroxypropyl)-cyclopentanone, 2-(1-hydroxybutyl)-cyclopentanone, 2-(1-hydroxypentyl)-cyclopentan-1-one, and 2-(1-hydroxyhexyl)-cyclopentanone are preferred, with 2-(1-hydroxypentyl)-cyclopentan-1-one being particularly preferred.

[0067] Specific examples of compound (V) include 2-propyl-2-cyclopenten-1-one, 2-butyl-2-cyclopenten-1-one, 2-pentyl-2-cyclopenten-1-one, 2-hexyl-2-cyclopenten-1-one, 2-(1-methylbutyl)-2-cyclopenten-1-one, 2-(2-methylbutyl)-2-cyclopenten-1-one, 2-cyclopentyl-2-cyclopenten-1-one, and 2-cyclohexyl-2-cyclopenten-1 Examples include -one, 2-propyl-2-cyclohexen-1-one, 2-butyl-2-cyclohexen-1-one, 2-pentyl-2-cyclohexen-1-one, 2-hexyl-2-cyclohexen-1-one, 2-(1-methylbutyl)-2-cyclohexen-1-one, 2-(2-methylbutyl)-2-cyclohexen-1-one, 2-cyclopentyl-2-cyclohexen-1-one, and 2-cyclohexyl-2-cyclohexen-1-one. Among these, 2-propyl-2-cyclopenten-1-one, 2-butyl-2-cyclopenten-1-one, 2-pentyl-2-cyclopenten-1-one, and 2-hexyl-2-cyclopenten-1-one are preferred, and 2-pentyl-2-cyclopenten-1-one is particularly preferred.

[0068] Specific examples of compound (VI) include dimethyl malonate, diethyl malonate, and dibutyl malonate. Of these, diethyl malonate is preferred.

[0069] Specific examples of compound (VII) include methyl dihydrojasmonate.

[0070] [Method for producing the compound of formula (I)] In the present invention, the compound of formula (I) can be produced by isomerizing the compound of formula (II) in the presence of molecular hydrogen and / or a hydrogen source, a platinum group metal catalyst, and a group 16 element (excluding oxygen) or a compound thereof.

[0071] <Molecular hydrogen and / or hydrogen sources> The hydrogen source may be a hydrogen transfer agent. Examples of hydrogen transfer agents include tetralin, formic acid, limonene, and cyclohexanol. Molecular hydrogen and the hydrogen source may be used in combination.

[0072] The molecular hydrogen can be used in a state mixed with an inert gas. The inert gas may be selected from the group consisting of, for example, nitrogen, argon, and helium. When the molecular hydrogen and the inert gas are used in a mixture, the mixing ratio (volume ratio, molecular hydrogen / inert gas) is preferably 1 / 10 or more, more preferably 1 / 5 or more, and even more preferably 1 / 3 or more from the viewpoint of reactivity, and preferably 10 / 1 or less, more preferably 5 / 1 or less, even more preferably 3 / 1 or less, preferably 10 / 1 to 1 / 10, more preferably 5 / 1 to 1 / 5, and even more preferably 3 / 1 to 1 / 3 from the viewpoint of suppressing side reactions.

[0073] <Platinum group metal catalyst> The platinum group metal catalyst used in the present invention is a catalyst that mainly contains one or more metal components selected from the group consisting of osmium (Os), ruthenium (Ru), iridium (Ir), rhodium (Rh), platinum (Pt), and palladium (Pd), which are elements of Groups 8 to 10 of Periods 5 to 6 of the periodic table. Among these metal components, Pt and Pd are preferred, and Pd is more preferred, from the viewpoint of catalytic activity, etc. Furthermore, these metal components can be used individually or in combination of two or more. Here, "mainly contains" means that the catalyst metal component contains preferably 50 mol% or more, more preferably 70 mol% or more, more preferably 90 mol% or more, and even more preferably 95 mol% or more of the component.

[0074] These platinum group metal catalysts may contain other metal components or secondary co-catalysts. Examples of such other metal components include, for example, the elements of Groups 4-11 of Period 4 of the periodic table, such as Ti, V, Cr, Mn, Fe, Co, Ni, and Cu, as well as W, Ag, and Au.

[0075] The catalyst can be prepared and used in various forms, such as supported type, Raney type, soluble type, powder, or granules, as appropriate.

[0076] Supported catalysts are catalysts in which metal components are supported on a carrier to improve the physical properties of the catalyst, such as its durability. Supported catalysts can be prepared by known methods such as precipitation, ion exchange, evaporation to dryness, spray drying, and kneading. Examples of carriers include carbon (activated carbon), alumina, silica, silica-alumina, barium sulfate, and calcium carbonate. Among these, carbon (activated carbon), silica, alumina, and silica-alumina are preferred.

[0077] Specific examples of palladium catalysts used as catalysts include palladium carbon, palladium-supported alumina, palladium-supported barium sulfate, and palladium-supported calcium carbonate. Among these, palladium carbon and palladium-supported alumina are preferred due to their high reactivity and the ease with which the palladium catalyst can be recovered after the reaction. Palladium carbon is particularly preferred from the viewpoint of availability, ease of handling, and reactivity.

[0078] In supported catalysts, the amount of metal component supported is preferably around 0.1 to 70% by mass, based on the total amount of the support and the supported metal component, from the viewpoint of catalytic activity.

[0079] The amount of platinum group metal catalyst used can be appropriately optimized depending on the reaction type. Specifically, from the viewpoint of reactivity and economy, the amount of metal relative to the raw material compound (II) is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more, from the viewpoint of improving yield, and from the viewpoint of economy, the amount of metal is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. The amount of platinum group metal catalyst used is preferably 0.01% by mass or more and 20% by mass or less, more preferably 0.05% by mass or more and 10% by mass or less, and even more preferably 0.1% by mass or more and 5% by mass or less, relative to the raw material compound (II).

[0080] <Elemental elements of Group 16 (excluding oxygen) or their compounds> In this invention, the shortening of the reaction time and high reaction yield of the isomerization reaction can be achieved because the elemental group 16 elements (excluding oxygen) or their compounds adsorb onto the platinum group metal catalyst, changing the electronic state of the metal surface. This stabilizes the adsorption state of α,β-unsaturated carbonyls onto the metal surface, thereby reducing the activation energy of the isomerization reaction. In other words, the elemental group 16 elements (excluding oxygen) or their compounds are thought to act as catalyst modifiers.

[0081] Group 16 elements (excluding oxygen) and their compounds may be used in combination.

[0082] Group 16 elements include one or more selected from sulfur, selenium, and tellurium. In particular, the elemental Group 16 elements (excluding oxygen) or compounds thereof preferably include one or more selected from the group consisting of sulfur and sulfur compounds, selenium and selenium compounds, and tellurium and tellurium compounds, and more preferably include sulfur.

[0083] The sulfur compounds are preferably compounds having a sulfide group, a thiophene ring, or a thiol group. Examples include sulfide compounds having a hydrocarbon group with 1 to 18 carbon atoms, such as dodecyl sulfide (didodecyl sulfide) and methyl dodecyl sulfide; alkylthiophenes and polyalkylthiophenes; and thiol compounds having a hydrocarbon group with 1 to 18 carbon atoms, such as dodecylthiol (1-dodecanethiol).

[0084] Among these, sulfur or sulfur compounds are preferred as Group 16 elements (excluding oxygen) or their compounds from the viewpoint of availability, ease of handling, and reactivity, and sulfur is more preferred from the viewpoint of being recoverable and reusable. Sulfur is also called elemental sulfur. Furthermore, when sulfur is used as a Group 16 element (excluding oxygen) or its compound, the reaction efficiency is almost maintained even when the platinum group metal catalyst is reused, which is therefore preferable.

[0085] The aforementioned Group 16 elements (excluding oxygen) or compounds thereof are preferably those that, in X-ray electron spectroscopy (XPS or ESCA), can shift the spectral peak of the Pd 3d orbital to a higher energy side by 0.1 to 1.0 eV compared to the catalyst before use. For example, when 13 mol% of elemental sulfur is used relative to Pd, the Pd / C Pd3d peak shifts from 335.5 eV and 340.8 eV to 335.9 eV and 341.1 eV.

[0086] The measurement conditions for X-ray electron spectroscopy are as follows: Equipment: PHI Quantera SXM (ULVAC PHI Inc.) Line source: Monochromatic Al Kα (1486.6eV), output 25W, 15kV Beam diameter: 100 μm spot analysis Pass energy:280.0eV(survey) 112.0eV(narrow) Step:1.00eV(survey)0.20eV(narrow) Charge correction: neutralizer and Ar Photoelectron extraction angle: 45°

[0087] The amount of the Group 16 element (excluding oxygen) or its compound used is preferably 100 mol% or less, more preferably 60 mol% or less, and even more preferably 40 mol% or less, relative to the amount of metal in the platinum group metal catalyst used, from the viewpoint of isomer yield, preferably 0.1 mol% or more, more preferably 0.5 mol% or more, and even more preferably 1 mol% or more. The amount of the Group 16 element (excluding oxygen) or its compound used is preferably 0.1 mol% to 100 mol%, more preferably 0.5 mol% to 60 mol%, and even more preferably 1 mol% to 40 mol%, relative to the amount of metal in the platinum group metal catalyst used. The amount of the Group 16 element (excluding oxygen) or its compound used is the total amount of the Group 16 element (excluding oxygen) and its compound.

[0088] The isomerization reaction can be carried out, for example, at 80°C to 250°C. From the viewpoint of reactivity and selectivity, the temperature of the isomerization reaction is preferably 100°C to 200°C, and more preferably 120°C to 160°C.

[0089] Isomerization reactions can proceed at normal pressure, but they can be carried out more efficiently under reduced pressure. The reaction pressure is preferably in the range of 20 to 200 kPa, and more preferably in the range of 50 to 150 kPa, depending on the reaction temperature.

[0090] <Solvent> The present invention can be carried out with or without a solvent. Not using a solvent is advantageous from the viewpoint of productivity and economy. The solvent is not particularly limited, but inert organic solvents such as methanol, ethanol, propanol, isopropanol, isobutanol, tert-butanol, n-butanol, 2-butanol, isopentanol, pentanol, hexanol, 2-ethylbutanol, heptanol, 2-heptanol, octanol, 2-octanol, cyclopentanol, cyclohexanol, ethylene glycol, propylene glycol, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, propylene glycol monoethyl ether, diethylene glycol, diethylene glycol monomethyl ether, benzyl alcohol, phenylethanol and other alcohols, methyl ethyl ketone, methyl isopropyl ketone, methyl propyl ketone, methyl isobutyl ketone, methyl n-butyl ketone, methyl n-amyl ketone, methyl isoamyl ketone, ethyl butyl ketone, methyl n-hexyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone Ketones such as cyclohexanone, isopropyl ether, n-butyl ether, 1,4-dioxane, isoamyl ether, n-hexyl ether, tetrahydropyran-2-methylfuran, diethylene glycol diethyl ether, methylphenyl ether, ethylphenyl ether and other ethers, n-methyl formate, n-propyl formate, n-butyl formate, methyl acetate, isopropyl acetate, n-butyl acetate, n-amyl acetate, n-hexyl acetate, cyclohexyl acetate, ethyl propionate, propio Examples of solvents include esters such as n-butyl benzoate, methyl butyrate, n-butyl butyrate, methyl isovalerate, ethyl lactate, methyl benzoate, propyl benzoate, dimethyl phthalate, diethyl oxalate, dimethyl succinate, dimethyl glutarate, and dimethyl adipate; and hydrocarbons such as n-hexane, n-octane, n-decane, ligroin, cyclohexane, benzene, toluene, xylene, ethylbenzene, isopropylbenzene, amylbenzene, t-butylbenzene, p-cymene, tetralin, and decalin. These solvents can be used individually or in combination of two or more.

[0091] The amount of solvent used is preferably 0.1 to 5 times the mass of the raw material compound (II), and more preferably 0.3 to 2 times the mass.

[0092] [Steps to obtain the compound of formula (II)] As described above, the present invention is a method for producing a compound represented by general formula (I), further comprising the step of dehydrating a compound represented by general formula (III) in the presence of an acid to obtain a compound represented by general formula (II).

[0093] In the dehydration step of the above method, the presence of molecular hydrogen and / or a hydrogen source, an acid, the platinum group metal catalyst, and the group 16 elements (excluding oxygen) in their elemental form or compounds thereof is preferable from the viewpoint of carrying out the dehydration reaction and the isomerization reaction in succession.

[0094] In other words, a preferred method for producing a compound represented by general formula (I) further includes the step of dehydrating a compound represented by general formula (III) in the presence of molecular hydrogen and / or a hydrogen source, an acid, the platinum group metal catalyst, and the group 16 elements (excluding oxygen) in their elemental form or a compound thereof to obtain a compound represented by general formula (II).

[0095] [ka]

[0096] During the ceremony, R 1 , R 2 and R 4 This simultaneously or independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms. R 3 This represents a linear or branched alkyl group with 1 to 8 carbon atoms, or a linear or branched alkenyl group with 2 to 8 carbon atoms. or R 1 and R 4This simultaneously or independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms. R 2 and R 3 Together, these represent either an alkanediyl group with 2 to 9 carbon atoms, or an alkanediyl group with 2 to 9 carbon atoms substituted with 1 to 2 alkyl groups with 1 to 5 carbon atoms.

[0097] <Molecular hydrogen and / or hydrogen sources> The molecular hydrogen and / or hydrogen source are the same as described above. When the molecular hydrogen and inert gas are mixed and used in this step, the mixing ratio (volume ratio, molecular hydrogen / inert gas) is preferably 1 / 10 or more, more preferably 1 / 5 or more, and even more preferably 1 / 3 or more, from the viewpoint of reactivity, and from the viewpoint of suppressing side reactions, it is preferably 10 / 1 or less, more preferably 5 / 1 or less, even more preferably 3 / 1 or less, preferably 10 / 1 to 1 / 10, more preferably 5 / 1 to 1 / 5, and even more preferably 3 / 1 to 1 / 3.

[0098] <Platinum group metal catalyst> The platinum group metal catalyst is the same as described above. The amount of the platinum group metal catalyst used can be appropriately optimized depending on the reaction type. Specifically, from the viewpoint of reactivity and economy, the amount of metal relative to the raw material compound (III) is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more, from the viewpoint of improving yield, and from the viewpoint of economy, the amount of metal is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. The amount of platinum group metal catalyst used is preferably 0.01% by mass or more and 20% by mass or less, more preferably 0.05% by mass or more and 10% by mass or less, and even more preferably 0.1% by mass or more and 5% by mass or less, relative to the raw material compound (III).

[0099] <Elemental elements of Group 16 (excluding oxygen) or their compounds> The same applies to the Group 16 elements (excluding oxygen) or their compounds. The amount of the Group 16 elements (excluding oxygen) or their compounds used is preferably 100 mol% or less, more preferably 60 mol% or less, even more preferably 40 mol% or less, relative to the amount of metal in the platinum group metal catalyst used, from the viewpoint of isomer yield, preferably 0.1 mol% or more, more preferably 0.5 mol% or more, even more preferably 1 mol% or more. The amount of the Group 16 elements (excluding oxygen) or their compounds used is preferably 0.1 mol% or more and 100 mol% or less, more preferably 0.5 mol% or more and even more preferably 1 mol% or more, relative to the amount of metal in the platinum group metal catalyst used. The amount of the Group 16 elements (excluding oxygen) or their compounds used is the total amount of the Group 16 elements (excluding oxygen) and their compounds.

[0100] <acid> The acid used in this invention can be one or more selected from inorganic acids, organic acids, and solid acids. Solid acids are preferred from the viewpoint of separation and removal from the reaction mixture.

[0101] Common acids can be used as inorganic and organic acids. Specifically, examples include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, and tripolyphosphoric acid, as well as organic acids such as acetic acid, oxalic acid, citric acid, maleic acid, fumaric acid, and malic acid.

[0102] Among these acids, from the viewpoint of suppressing metal corrosion, acids with a first-stage acid dissociation index (pKa) of 0 or higher, preferably 0.5 or higher, at 25°C are preferred. Specifically, examples include phosphoric acid (first-stage pKa: 2.15), pyrophosphoric acid (first-stage pKa: 0.8), condensed phosphoric acid such as tripolyphosphoric acid, and organic acids such as acetic acid (first-stage pKa: 4.56), oxalic acid (first-stage pKa: 1.04), citric acid (first-stage pKa: 2.87), maleic acid (first-stage pKa: 1.75), fumaric acid (first-stage pKa: 2.85), and malic acid (first-stage pKa: 3.24).

[0103] As the solid acid, known solid acids can be used. Specifically, examples include inorganic metal solids such as activated carbon, activated alumina, zirconia sulfate, metal phosphates, aluminum dihydrogen tripolyphosphate, and titanium oxide, as well as cation exchange resins, silica-titania composite oxides, silica-calcium oxide composite oxides, silica-magnesia composite oxides, and zeolites.

[0104] In the Temperature Programmed Desorption (TPD) method, it is more preferable that the amount of acid sites (mmol / g) that cause ammonia (NH3) desorption in the temperature range of 100 to 250°C is greater than the amount of acid sites (mmol / g) that cause NH3 desorption at temperatures above 250°C. It is more preferable that the amount of acid sites that cause NH3 desorption in the 100 to 250°C range is 0.01 mmol / g or more, and the amount of acid sites that cause NH3 desorption at temperatures above 250°C is less than 0.3 mmol / g. For example, the phosphate-supported activated carbon described in the examples below has an amount of acid sites that cause NH3 desorption in the 100 to 250°C range in the TPD method of 0.02 mmol / g.

[0105] The amount of acid sites mentioned above is measured relative to the high peak (the higher-temperature peak of the two observed peaks) of the zeolite JRC-Z5-25H, a reference catalyst of the Catalysis Society of Japan, which is set at 0.99 mmol / g. Peak detection is performed by quantifying ammonia using the m / e=16 fragment of the ammonia mass spectrum.

[0106] For measuring TPD (ammonia temperature-induced desorption), commonly used methods can be employed. For example, after performing pretreatment, NH3 adsorption treatment, and vacuum treatment in sequence under the following conditions, TPD measurement is performed. Pre-treatment: Heat in helium to 200°C for 20 minutes, then hold for 1 hour. NH3 adsorption treatment: NH3 is adsorbed at 50°C and 2.7kPa for 10 minutes. Vacuum treatment: 50°C, 4 hours TPD measurement: Helium gas is circulated at 50 ml / min, and the temperature is raised to 600°C at a heating rate of 5°C / min.

[0107] As a solid acid having such an acid site distribution, for example, one having at least one of the following structures (A), (B), and metal atom (C) is preferred, and among these, a solid acid containing structure (A) and metal atom (C), structure (B) and metal atom (C), and structure (A), structure (B), and metal atom (C) is preferred. The acid site of the solid acid as a whole is measured by the ammonia temperature-programmed desorption (TPD) method. Specifically, the overall acid site can be adjusted to a desired value by adjusting each of structures (A), (B), and (C). It is also possible to support structures (A) and (B) on a carrier. In that case, it is possible to adjust the overall acid site, including the carrier, to a desired value. • Structure (A): A structure in which at least one hydrogen atom has been removed from the OH group of inorganic phosphoric acid. • Structure (B): A structure in which at least one hydrogen atom has been removed from the OH group of an organophosphate. • Metal atoms (C): One or more metal atoms selected from aluminum, gallium, and iron.

[0108] Examples of structures (A) include condensed phosphoric acids such as orthophosphate, metaphosphate, and pyrophosphate, as well as phosphoric acid. Among these, orthophosphate and phosphoric acid are preferred in terms of performance.

[0109] Examples of structure (B) include phosphonic acid, phosphonic acid monoester, phosphinic acid, phosphate monoester, phosphate diester, phosphate monoester, and phosphate diester. Among these, phosphonic acid is preferred.

[0110] As for the metal atom (C), aluminum is preferred from the viewpoint of performance and / or cost.

[0111] Furthermore, small amounts of metal atoms other than aluminum, gallium, and iron may be present for the purpose of improving selectivity and other performance. Also, not all of the metal atoms (C) contained in the catalyst necessarily need to be bonded to structure (A) or structure (B); some of the metal atoms (C) may exist in the form of metal oxides or metal hydroxides, etc.

[0112] Methods for preparing solid acids include precipitation, impregnation of metal oxides or hydroxides with inorganic and organic phosphoric acids, and substitution of inorganic phosphate groups with organic phosphate groups in inorganic aluminum phosphate gel. Among these, precipitation is preferred.

[0113] Furthermore, when preparing a solid acid, it is possible to obtain a supported catalyst by coexisting with a support with a high surface area. Silica, alumina, silica-alumina, titania, zirconia, diatomaceous earth, activated carbon, etc., can be used as the support. Using an excess of support reduces the content of the active ingredient and thus the activity; therefore, the proportion of support in the catalyst is preferably 90% by weight or less.

[0114] The solid acid may be in powder or molded form. Furthermore, the solid acids may all have the same composition, or a combination of solid acids with different compositions may be used.

[0115] The inorganic acids, organic acids, and solid acids mentioned above can be used individually or in combination of two or more. When using only solid acids, the neutralization step can be omitted.

[0116] From the viewpoint of reactivity, the amount of solid acid used is preferably 0.0001% by mass or more relative to the compound of formula (III). On the other hand, from the viewpoint of suppressing polymerization between compounds containing the resulting double bond and improving the yield, the amount of solid acid used is preferably 25% by mass or less. From the above viewpoint, the amount of solid acid used is more preferably 0.001 to 12% by mass, and particularly preferably 0.01 to 6% by mass.

[0117] This process can be carried out, for example, at a temperature of 80°C to 250°C. From the viewpoint of reactivity and selectivity, the temperature for the isomerization reaction is preferably 120°C to 200°C, and more preferably 120°C to 160°C.

[0118] Although this process can proceed at atmospheric pressure, carrying out the reaction under reduced pressure allows for efficient removal of the generated water from the system and efficient reaction without distillation of the raw materials and reaction products. The reaction pressure is preferably in the range of 20 to 200 kPa, and more preferably in the range of 50 to 150 kPa, depending on the reaction temperature. In the method of the present invention, it is preferable to carry out the reaction while distilling off the generated water.

[0119] <Solvent> The solvent is as described above. The amount of solvent used is preferably 0.1 to 5 times the mass of the raw material compound (III), and more preferably 0.3 to 2 times the mass.

[0120] <Preparation of compound (III)> The compound of formula (III) used as a raw material can be produced by known methods. For example, it can be obtained by reacting a ketone represented by general formula (X) with an aldehyde represented by general formula (XI). The ketone represented by general formula (X) and the aldehyde represented by general formula (XI) can be obtained commercially or produced by known methods.

[0121] [ka]

[0122] During the ceremony, R 1 , R 2 and R 4 This simultaneously or independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms. R 3 This represents a linear or branched alkyl group with 1 to 8 carbon atoms, or a linear or branched alkenyl group with 2 to 8 carbon atoms. or R 1 and R 4 This simultaneously or independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms. R 2 and R 3 Together, these represent either an alkanediyl group with 2 to 9 carbon atoms, or an alkanediyl group with 2 to 9 carbon atoms substituted with 1 to 2 alkyl groups with 1 to 5 carbon atoms.

[0123] In this invention, compound (III) obtained by this method can be used without purification, but if the catalytic activity decreases, it may be produced by distillation or other means before use.

[0124] [Method for producing the compound of formula (VII)] The present invention is a method for producing a compound of formula (VII), comprising the following steps 1 and 2. Step 1: A step in which a compound represented by the following general formula (IV) is dehydrated and isomerized in the presence of molecular hydrogen and / or a hydrogen source, an acid, a platinum group metal catalyst, and a Group 16 element (excluding oxygen) or a compound thereof, to obtain a compound represented by the following general formula (V). Step 2: A step to obtain a compound represented by general formula (VII) by reacting the compound represented by general formula (V) obtained in Step 1 with a malonic acid diester represented by general formula (VI) below, and then reacting it with water.

[0125] [ka]

[0126] During the ceremony, R 1 and R 4 This simultaneously or independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms. R 2 'and R 3' together represents an alkanediyl group with 2 to 9 carbon atoms, or an alkanediyl group with 2 to 9 carbon atoms substituted with 1 to 2 alkyl groups with 1 to 5 carbon atoms. R 7 represents an alkyl group with 1 to 3 carbon atoms, and the two R's 7 They may be the same or different.

[0127] Compounds of general formula (IV) (hereinafter sometimes referred to as "compounds of formula (IV)" or "compound (IV)") are R of compounds of formula (III). 2 and R 3 This corresponds to a limited definition. Also, a compound of general formula (V) (hereinafter sometimes referred to as "a compound of formula (V)" or "compound (I)") is the R of a compound of formula (V). 2 and R 3 This corresponds to a limited definition.

[0128] <Process 1> Step 1 of this manufacturing method, "the step of dehydrating and isomerizing a compound represented by the following general formula (IV) in the presence of molecular hydrogen and / or a hydrogen source, an acid, a platinum group metal catalyst, and a Group 16 element (excluding oxygen) or a compound thereof, to obtain a compound represented by the following general formula (V)," is carried out according to the manufacturing method of the compound represented by general formula (I), that is, the manufacturing method of the compound represented by general formula (I), which further includes the step of dehydrating a compound represented by general formula (III) in the presence of molecular hydrogen and / or a hydrogen source, an acid, the platinum group metal catalyst, and a Group 16 element (excluding oxygen) or a compound thereof, to obtain a compound represented by general formula (II). In other words, in the manufacturing method of the compound of formula (I), the compound of formula (IV) is substituted for the compound of formula (III), and the compound of formula (V) is substituted for the compound of formula (I), and the method is carried out.

[0129] <Process 2> Step 2 is a step in which the compound of formula (V) obtained in Step 1 is reacted with a malonic acid diester represented by general formula (VI), and then reacted with water to obtain a compound represented by general formula (VII) (hereinafter sometimes referred to as "compound of formula (VII)" or "compound (VII)").

[0130] Specifically, the compound of formula (V) and the malonic acid diester of formula (VI) are first reacted in the presence of a base to obtain the compound represented by general formula (VIII) (hereinafter sometimes referred to as "compound of formula (VIII)" or "compound (VIII)").

[0131] [ka]

[0132] In the formula, R 1 , R 2 ', R 3 ', R 4 , R 7 As defined above, two R 7 They may be the same or different.

[0133] Compound (VII) is reacted with the raw material compound (V) in a ratio of preferably 1 to 5 molars, more preferably 1.2 to 2 molars.

[0134] Examples of bases that can be used include alkali metals such as sodium and potassium, and alkali metal alkoxides such as sodium alkoxide and potassium alkoxide.

[0135] The amount of base used is preferably 0.005 to 0.2 molar times the amount of compound (V), and more preferably 0.01 to 0.1 molar times. A polar solvent such as alcohols is preferred as the solvent.

[0136] The reaction temperature is preferably -10 to 30°C, and more preferably -2 to 20°C.

[0137] Next, compound (VII) can be produced by reacting the obtained compound (VIII) with water. It is preferable to add water in an amount of 1 to 3 molar times the amount of compound (VIII), and to react while adding it dropwise into the reaction system. The reaction temperature at this time is preferably 150 to 230°C, and more preferably 180 to 220°C.

[0138] [ka]

[0139] [In the formula, R 1 , R 2 ', R 3 ', R 4 , R 7 As defined above, two R 7 They may be the same or different.

[0140] The compound (VII) obtained in this way has a higher yield and fewer impurities compared to conventional methods, thus reducing the purification burden required to obtain compound (VII) in high purity, making it an excellent fragrance material.

[0141] With regard to the embodiments described above, the present invention further discloses the following methods. [1] A method for producing a compound represented by the following general formula (I), comprising the step of isomerizing a compound represented by the following general formula (II) in the presence of molecular hydrogen and / or a hydrogen source, a platinum group metal catalyst, and a group 16 element (excluding oxygen) or a compound thereof.

[0142] [ka]

[0143] [In the formula, R 1 , R 2 , and R 4 This simultaneously or independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms. R 3 This represents a linear or branched alkyl group with 1 to 8 carbon atoms, or a linear or branched alkenyl group with 2 to 8 carbon atoms. or R 1 and R 4This simultaneously or independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms. R 2 and R 3 Together, these represent either an alkanediyl group with 2 to 9 carbon atoms, or an alkanediyl group with 2 to 9 carbon atoms substituted with one or two alkyl groups with 1 to 5 carbon atoms.

[0144] [2] In the formula, R 2 and R 3 However, together they represent an alkanediyl group having 2 to 9 carbon atoms. [1] The manufacturing method described above.

[0145] [3] The manufacturing method according to [1] or [2], wherein the metal of the platinum group metal catalyst is one or more selected from the group consisting of osmium (Os), ruthenium (Ru), iridium (Ir), rhodium (Rh), platinum (Pt), and palladium (Pd).

[0146] [4] The manufacturing method according to any one of [1] to [3], wherein the metal of the platinum group metal catalyst is palladium or platinum.

[0147] [5] The manufacturing method according to any one of [1] to [4], wherein the metal of the platinum group metal catalyst is supported on carbon.

[0148] [6] The manufacturing method according to any one of [1] to [5], wherein the amount of platinum group metal catalyst used is 0.01% by mass or more and 20% by mass or less in terms of metal content relative to the raw material compound (II).

[0149] [7] The manufacturing method according to any one of [1] to [6], wherein the amount of platinum group metal catalyst used is 0.05% by mass or more and 10% by mass or less in terms of metal content relative to the raw material compound (II).

[0150] [8] The manufacturing method according to any one of [1] to [7], wherein the amount of platinum group metal catalyst used is 0.1% by mass or more and 5% by mass or less in terms of metal content relative to the raw material compound (II).

[0151] [9] The method for producing the element (excluding oxygen) or compound thereof according to any one of [1] to [8], wherein the element (excluding oxygen) or compound thereof comprises one or more selected from the group consisting of sulfur and sulfur compounds, selenium and selenium compounds, and tellurium and tellurium compounds.

[0152]

[10] The method of production according to any one of [1] to [9], wherein the sulfur compound is a compound having a sulfide group, a thiophene ring, or a thiol group.

[0153]

[11] The method for producing the Group 16 element (excluding oxygen) or a compound thereof containing sulfur, according to any one of [1] to

[10] .

[0154]

[12] A method for producing molecular hydrogen, wherein molecular hydrogen is mixed with an inert gas, and the inert gas is one or more selected from the group consisting of nitrogen, argon, and helium, according to any one of [1] to

[11] .

[0155]

[13] The manufacturing method according to any one of [1] to

[12] , wherein the volume ratio of molecular hydrogen to the inert gas (molecular hydrogen / inert gas) is 10 / 1 to 1 / 30.

[0156]

[14] The manufacturing method according to any one of [1] to

[13] , wherein the volume ratio of molecular hydrogen to the inert gas (molecular hydrogen / inert gas) is 5 / 1 to 1 / 20.

[0157]

[15] The manufacturing method according to any one of [1] to

[14] , wherein the volume ratio of molecular hydrogen to the inert gas (molecular hydrogen / inert gas) is 3 / 1 to 1 / 10.

[0158]

[16] The manufacturing method according to any one of [1] to

[15] , wherein the amount used of the Group 16 element (excluding oxygen) or a compound thereof is 0.1 mol% or more and 100 mol% or less relative to the amount of metal in the platinum group metal catalyst.

[0159]

[17] The production method according to any one of [1] to

[16] , wherein the amount of the Group 16 element (excluding oxygen) alone or its compound used is 0.5 mol% or more and 60 mol% or less based on the amount of the metal of the platinum group metal catalyst.

[0160]

[18] The production method according to any one of [1] to

[17] , wherein the amount of the Group 16 element (excluding oxygen) alone or its compound used is 1 mol% or more and 40 mol% or less based on the amount of the metal of the platinum group metal catalyst.

[0161]

[19] The production method according to any one of [1] to

[18] , wherein the isomerization reaction is carried out at 80°C to 250°C.

[0162]

[20] The production method according to any one of [1] to

[19] , wherein the isomerization reaction is carried out at 100°C to 200°C.

[0163]

[21] The production method according to any one of [1] to

[20] , wherein the isomerization reaction is carried out at 120°C to 160°C.

[0164]

[22] The production method according to any one of [1] to

[21] , further comprising a step of dehydrating the compound represented by the general formula (III) in the presence of molecular hydrogen and / or a hydrogen source, an acid, the platinum group metal catalyst, and the Group 16 element (excluding oxygen) alone or its compound to obtain the compound represented by the general formula (II).

[0165]

Chemical formula

[0166] [In the formula, R 1 、R 2 and R 4 each represents, simultaneously or independently, a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms, R 3represents a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms, or or R 1 and R 4 simultaneously or independently represent a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms, R 2 and R 3 together represent an alkanediyl group having 2 to 9 carbon atoms, or an alkanediyl group having 2 to 9 carbon atoms substituted with 1 to 2 alkyl groups having 1 to 5 carbon atoms.]

[0167]

[23] The production method according to

[22] , wherein the acid contains a solid acid.

[0168]

[24] The production method according to

[22] or

[23] , wherein the amount of the solid acid used is 0.001 to 12% by mass based on the compound of formula (III).

[0169]

[25] The production method according to any one of

[22] to

[24] , wherein the amount of the solid acid used is 0.01 to 6% by mass based on the compound of formula (III).

[0170]

[26] In the formula, R 2 and R 3 together form an alkanediyl group having 2 to 9 carbon atoms, the production method according to any one of [1] to

[25] .

[0171]

[27] In the formula, R 2 and R 3 together form an alkanediyl group having 2 to 4 carbon atoms, the production method according to any one of [1] to

[26] .

[0172]

[28] In the formula, R 2 and R 3 together form an alkanediyl group having 2 carbon atoms, the production method according to any one of [1] to

[27] .

[0173]

[29] In the formula, R 1However, the alkyl group having 1 to 4 carbon atoms is the manufacturing method described in any of [1] to

[28] .

[0174]

[30] In the formula, R 1 The manufacturing method described in any of [1] to

[29] , wherein the material is an n-butyl group.

[0175]

[31] In the formula, R 4 However, the manufacturing method described in any of [1] to

[30] , wherein the atom is a hydrogen atom.

[0176]

[32] In the formula, R 1 However, it is an n-butyl group, R 2 and R 3 However, together they form a carbon-2 alkanediyl group, R 4 However, the manufacturing method described in any of [1] to

[31] , wherein the atom is a hydrogen atom.

[0177]

[33] The method for producing a compound represented by the general formula (III) described above, wherein the compound is 2-(1-hydroxypentyl)-cyclopentan-1-one [1] to

[32] .

[0178]

[34] A method for producing the compound of formula (VII), comprising steps 1 and 2 below. Step 1: A step in which a compound represented by the following general formula (IV) is dehydrated and isomerized in the presence of molecular hydrogen and / or a hydrogen source, an acid, a platinum group metal catalyst, and a Group 16 element (excluding oxygen) or a compound thereof, to obtain a compound represented by the following general formula (V). Step 2: A step to obtain a compound represented by general formula (VII) by reacting the compound represented by general formula (V) obtained in Step 1 with a malonic acid diester represented by general formula (VI) below, and then reacting it with water.

[0179] [ka]

[0180] [In the formula, R 1 and R 4represents, simultaneously or independently, a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms, R 2 ’ and R 3 ’ together represent an alkanediyl group having 2 to 9 carbon atoms or an alkanediyl group having 2 to 9 carbon atoms substituted with 1 to 2 alkyl groups having 1 to 5 carbon atoms, R 7 represents an alkyl group having 1 to 3 carbon atoms, and two R 7 may be the same or different.]

[0181]

[35] R 2 ’ and R 3 ’ together form an alkanediyl group having 2 to 4 carbon atoms in the production method described in

[34] . The production method according to claim 1.

[0182]

[36] R 2 ’ and R 3 ’ together form an alkanediyl group having 2 carbon atoms in the production method described in

[34] or

[35] . The production method according to claim 1.

[0183]

[37] R 1 is an alkyl group having 1 to 4 carbon atoms, in the production method described in any one of

[34] to

[36] .

[0184]

[38] R 1 is an n-butyl group, in the production method described in any one of

[34] to

[37] .

[0185]

[39] R 4 is a hydrogen atom, in the production method described in any one of

[34] to

[38] .

[0186]

[40] R 7 is a methyl group, in the production method described in any one of

[34] to

[39] .

[0187]

[41] R 1 is an n-butyl group, and R 2 ’ and R 3', together they form a carbon-2 alkanediyl group, R 4 However, it is a hydrogen atom, R 7 However, the method of manufacturing the methyl group as described in any of

[34] to

[40] .

[0188] In the following reference examples, examples, and comparative examples, "%" refers to "mass%" unless otherwise specified. The operating pressure is 101 lPa (atmospheric pressure) unless otherwise specified. The mass of the catalyst is the mass in a dry state.

[0189] <Gas chromatography equipment and analytical conditions> GC system: Agilent Technologies, Inc. 7890, flame ionization detector; Column: For yield analysis, DB-1 (capillary column, 100% dimethylpolysiloxane, inner diameter 0.25 mm, length 30 m, film thickness 0.25 μm, manufactured by Agilent Technologies, Inc.) was used. Carrier gas: He, 1.6 mL / min Injection conditions: 200°C, split ratio 100 / 1 Injection volume: 1 μL Detection conditions: FID method, 280°C The analysis was performed using the internal standard method (internal standard: undecane (manufactured by Tokyo Chemical Industry Co., Ltd., purity 99%)). Column temperature conditions: Starting at 100°C, the temperature was increased at a rate of 5°C / min to 210°C. Then, the temperature was increased at a rate of 20°C / min to 280°C and held at 280°C for 4.5 minutes.

[0190] [Reference example 1] Preparation of 2-(1-hydroxypentyl)-cyclopentan-1-one (4)

[0191] [ka]

[0192] 6m with drip layer 3Cyclopentanone (1) (2241 kg), water (1007 kg), and 48% NaOH (11 kg) were charged into the reaction vessel. The mixture in the reaction vessel was cooled to 15°C while stirring, and then barrelaldehyde (2) (985 kg) was added dropwise at the same temperature over 5 hours. After the addition was complete, the reaction mixture was stirred for 1 hour. The reaction mixture was neutralized, and the excess cyclopentanone was recovered from the mixture by distillation. The remaining organic layer (1868 kg) contained 1706 kg of 2-(1-hydroxypentyl)-cyclopentan-1-one (4). Note that 2-(1-hydroxypentyl)-cyclopentan-1-one (4) is a known compound, and its structure was confirmed by publicly available literature such as Japanese Patent Publication No. 2009-269910.

[0193] [Reference example 2] Manufacturing of 2-Pentylcyclopentan-1-one (7)

[0194] [ka]

[0195] In a 200 mL four-necked glass flask equipped with a connecting tube, 100 g of 2-(1-hydroxypentyl)-cyclopentan-1-one (4) (88% purity) obtained in Reference Example 1, 1.1 g of phosphate-supported activated carbon (powder), and 7.6 g of 5% Pd / C (powder, 60.4% hydrated) were added. The mixture was stirred at 400 rpm using a crescent-shaped vane (vane diameter 4 cm) under a nitrogen:hydrogen (volume ratio) of 1:0.33 and heated to 140°C and 101 kPa. During the reaction, the fraction was continuously distilled into a fractionation receiver connected to the flask.

[0196] Eleven hours after the start of the reaction, 15.4 g of fraction was obtained, and 93.3 g of the reaction product was obtained. Quantitative analysis of the reaction product by GC revealed that 2-pentyl-2-cyclopenten-1-one (3) (71.2 g) was produced, and 2-pentylcyclopentan-1-one (7) (2.7 g) was produced as a by-product. The yield of 2-pentyl-2-cyclopenten-1-one (3) was 89 mol%, and the production rate of 2-pentylcyclopentan-1-one (7) was 8 mol%. 2-Pentylcyclopentan-1-one (7) is a known compound, and its structure was confirmed by referring to publicly available literature such as Japanese Patent Publication No. 2009-269910.

[0197] <Effects of adding sulfur> [Example 1] In a 200 mL four-necked glass flask equipped with a connecting tube, 100 g of 2-(1-hydroxypentyl)-cyclopentan-1-one (4) (80% purity) obtained in Reference Example 1, 1.1 g of phosphate-supported activated carbon (powder, 1.3% by mass relative to compound (4)), 7.6 g of 5% Pd / C (powder, 60.4% hydrated, 3.7% by mass relative to compound (4)), and sulfur powder (Fujifilm Wako Pure Chemical Industries, powder, 2.2 mg, 4 mol relative to the amount of platinum group metal catalyst) were added. The mixture was stirred at 400 rpm using a crescent-shaped vane (vane diameter 4 cm) under a nitrogen:hydrogen (volume ratio) of 1:0.33 and heated to 140 °C and 101 kPa. During the reaction, the fraction was continuously distilled into a fractionation receiver connected to the flask.

[0198] Eight hours after the start of the reaction, 15.2 g of fraction and 93.5 g of reaction product were obtained. Quantitative analysis of the reaction product by GC revealed that 2-pentyl-2-cyclopenten-1-one (3) (56.4 g) was produced, and 2-pentylcyclopentan-1-one (7) (1.4 g) was produced as a by-product. The yield of 2-pentyl-2-cyclopenten-1-one (3) was 76%, and the production rate of 2-pentylcyclopentan-1-one (7) was 2%.

[0199] [Examples 2-4] The procedure was the same as in Example 1, except that the amount of sulfur powder was changed to the amount shown in Table 1. The yield of 2-pentyl-2-cyclopenten-1-one (3) and the production rate of 2-pentylcyclopentan-1-one (7) are shown in Table 1.

[0200] [Comparative Example 1] The procedure was the same as in Example 1, except that sulfur powder was not used. The yield of 2-pentyl-2-cyclopenten-1-one (3) and the production rate of 2-pentylcyclopentan-1-one (7) are shown in Table 1.

[0201] [Table 1]

[0202] Table 1 shows that using sulfur powder as a Group 16 element improved the yield of isomerization from compound (4) to compound (3).

[0203] [Example 5] In a 500 mL four-neck separable flask (glass) equipped with a connecting tube, 2-(1-hydroxypentyl)-cyclopentan-1-one (4) (306 g, 80% purity) obtained in Reference Example 1, phosphate-supported activated carbon (powder, 3.3 g, 1.3 mass% relative to compound (4)), 5% Pd / C (powder, 61.7% hydrated, 7.83 g, 1.2 mass% relative to compound (4)), and sulfur powder (Fujifilm Wako Pure Chemical Industries, powder, 6.3 mg, 13 mol% relative to the amount of platinum group metal catalyst) were added. The mixture was stirred at 140°C at 400 rpm using a 6-blade disk turbine blade (blade diameter 3 cm) under an atmosphere of nitrogen:hydrogen (volume ratio) = 1:1.5, and heated to 101 kPa and mixed. During the reaction, the fraction was continuously distilled into a fraction receiver connected to the flask. After 8 hours of reaction, 36.7 g of fraction and 268.6 g of reaction product were obtained. The reaction product was quantified by GC. The yield of 2-pentyl-2-cyclopenten-1-one (3) and the production rate of 2-pentylcyclopentan-1-one (7) are shown in Table 2.

[0204] [Example 6] The procedure was the same as in Example 5, except that the amount of 5% Pd / C was changed to 3.91 g (powder, 61.7% hydrated, 0.6 mass%) relative to compound (4). The yields of 2-pentyl-2-cyclopenten-1-one (3) and the production rate of 2-pentylcyclopentan-1-one (7) obtained after 8 hours and 12 hours of reaction are shown in Table 2.

[0205] [Comparative Example 2] In a 500 mL four-necked separable flask (glass) equipped with a connecting tube, 2-(1-hydroxypentyl)-cyclopentan-1-one (4) (299 g, 89% purity) obtained in Reference Example 1, phosphate-supported activated carbon (powder, 3.3 g, 1.2% by mass relative to compound (4)), and 5% Pd / C (powder, 61.7% hydrated, 7.86 g, 1.1% by mass relative to compound (4)) were added. The mixture was stirred at 400 rpm using a 6-blade disk turbine impeller (blade diameter 3 cm) under an atmosphere of nitrogen:hydrogen (volume ratio) = 1:1.5, and heated to 140°C and 101 kPa, and then mixed. During the reaction, the fraction was continuously distilled into a fractionation receiver connected to the flask.

[0206] The reaction product, after removing the fractions obtained after 8 and 18 hours of reaction, was quantified by GC. The yield of 2-pentyl-2-cyclopenten-1-one (3) and the production rate of 2-pentylcyclopentan-1-one (7) are shown in Table 2.

[0207] [Table 2]

[0208] A comparison between Example 5 and Comparative Example 2, which used almost the same amount of metal catalyst, confirmed that the reaction time could be shortened. A comparison between Example 6 and Comparative Example 2 confirmed that the amount of metal catalyst could be reduced and the reaction time could be shortened.

[0209] <Effects of the amount of molecular hydrogen> [Example 7] In a 500 mL four-neck separable flask (glass) equipped with a connecting tube, 2-(1-hydroxypentyl)-cyclopentan-1-one (4) (301 g, 88% purity) obtained in Reference Example 1, phosphate-supported activated carbon (powder, 3.3 g, 1.2% by mass relative to compound (4)), 5% Pd / C (powder, 60.9% hydrated, 7.67 g, 1.1% by mass relative to compound (4)), and sulfur powder (Fujifilm Wako Pure Chemical Industries, powder, 7.0 mg, 13 mol% relative to the amount of platinum group metal catalyst) were added. The mixture was stirred at 400 rpm using a 6-blade disk turbine blade (blade diameter 3 cm) under a nitrogen:hydrogen (volume ratio) = 1:3 atmosphere, and heated to 140°C and 101 kPa, and then mixed. During the reaction, the fraction was continuously distilled into a fractionation receiver connected to the flask.

[0210] Eight hours after the start of the reaction, 38.2 g of fraction and 273.8 g of reaction product were obtained. The results of quantitative analysis of the reaction product by GC are shown in Table 3.

[0211] [Table 3]

[0212] Comparing Example 5 and Example 7, it was confirmed that Example 5, with a nitrogen:hydrogen (volume ratio) of 1:1.5, yielded a higher yield of compound (3).

[0213] <Effects of different types of Group 16 element compounds> [Examples 8, 9] The procedure was the same as in Example 6, except that the type of Group 16 element compound was changed to those shown in Table 4. The yields of 2-pentyl-2-cyclopenten-1-one (3) and the production rate of 2-pentylcyclopentan-1-one (7) obtained after 8 hours and 16 hours of reaction are shown in Table 4.

[0214] [Table 4]

[0215] From the results of Examples 6, 8, and 9, it was confirmed that sulfur powder, dodecyl sphide, and dodecanethiol, as individual Group 16 elements or compounds thereof, have similar effects.

[0216] <Isomerization of compound (3) from compound (5)> [Reference example 3]

[0217] [ka]

[0218] In a 1000 mL autoclave (made of stainless steel) equipped with a connecting tube, 2-(1-hydroxypentyl)-cyclopentan-1-one (4) (703 g, purity 86%) obtained in Reference Example 1 and phosphate-supported activated carbon (powder, 21.0 g) were added and heated under a nitrogen atmosphere to 140°C and 101 kPa, and mixed. During the reaction, the fraction was continuously distilled into a fraction receiver connected to the autoclave.

[0219] Two hours after the start of the reaction, the reaction mixture was cooled after removing the fraction, and the phosphate-activated activated carbon was removed by filtration. The resulting filtrate was purified by distillation. The resulting distilled fraction of 459.5 g contained 2-pentyl-2-cyclopenten-1-one (3) (24.3 g) and 2-pentylidenecyclopentan-1-one (5) (407.6 g). 2-pentylidenecyclopentan-1-one (5) is a known compound, and its structure was confirmed by the publicly available literature, Synthesis 1981; 1981(12): 1003-1004, etc.

[0220] [Example 10] In a 200 mL four-necked glass flask equipped with a connecting tube, 100 g of the distillation fraction obtained in Reference Example 3 (2-pentylidenecyclopentan-1-one (5) (90% purity) and 2-pentyl-2-cyclopenten-1-one (3) (5% purity), 5% Pd / C (powder, 59.9% hydrated, 2.5 g, 1.1% by mass relative to compound (5)), and sulfur powder (Fujifilm Wako Pure Chemical Industries, powder, 2.6 mg, 13 mol relative to the metal content of the platinum group metal catalyst) were added. The mixture was stirred at 400 rpm using a crescent-shaped vane (vane diameter 4 cm) under a nitrogen:hydrogen (volume ratio) of 1:1.5 and heated to 140°C and 101 kPa. During the reaction, the fraction was continuously distilled into a fraction receiver connected to the flask.

[0221] After 2 hours of reaction, 0.3 g of fraction was obtained, and 102.2 g of reaction product was obtained. Quantitative analysis of the reaction product by GC revealed that 2-pentyl-2-cyclopenten-1-one (3) (93.5 g) was produced, and 2-pentylcyclopentan-1-one (7) (2.0 g) was produced as a by-product. The yield of 2-pentyl-2-cyclopenten-1-one (3) was 98 mol%, and the production rate of 2-pentylcyclopentan-1-one (7) was 2 mol%.

[0222] [Comparative Example 3] In a 200 mL four-necked glass flask equipped with a connecting tube, 100 g of the distillation fraction obtained in Reference Example 3 (2-pentylidenecyclopentan-1-one (5) (90% purity) and 2-pentyl-2-cyclopenten-1-one (3) (5% purity)) and 5% Pd / C (powder, 59.9% hydrated, 7.5 g, 3.3 mass relative to compound (5)) were added. The mixture was stirred at 400 rpm using a crescent-shaped vane (vane diameter 4 cm) under a nitrogen:hydrogen (volume ratio) of 1:1.5 and heated to 140 °C and 101 kPa. During the reaction, the fraction was continuously distilled into a fraction receiver connected to the flask. After 4 hours of reaction, 4.0 g of fraction was obtained, and 103.5 g of the reaction product was obtained. The obtained reaction product was quantified by GC. The yield of 2-pentyl-2-cyclopenten-1-one (3) and the production rate of 2-pentylcyclopentan-1-one (7) are shown in Table 5.

[0223] [Comparative Example 4] The procedure was carried out in the same manner as in Comparative Example 4, except that the amount of 5% Pd / C was changed to 2.5 g (1.1 mass%) relative to compound (5). The yield of 2-pentyl-2-cyclopenten-1-one (3) and the production rate of 2-pentylcyclopentan-1-one (7) obtained after 2 hours of reaction are shown in Table 5.

[0224] [Table 5]

[0225] By comparing Example 10 with Comparative Example 3, it was confirmed that the amount of metal catalyst could be reduced and the reaction time could be shortened.

[0226] By comparing Example 10 with Comparative Example 4, which had the same amount of metal catalyst, it was confirmed that the yield of the isomerization reaction was improved.

[0227] [Example 11] In a 500 mL four-neck separable flask (glass) equipped with a connecting tube, 300 g of 2-(1-hydroxypentyl)-cyclopentan-1-one (4) (87% purity) obtained in Reference Example 1, 3.3 g of phosphate-supported activated carbon (powder, 1.3% by mass relative to compound (4)), 3.84 g of 5% Pd / C (powder, 60.9% hydrated, 0.6% by mass relative to compound (4)), and sulfur powder (Fujifilm Wako Pure Chemical Industries, powder, 2.9 mg, 13 mol% relative to the amount of metal in the platinum group metal catalyst) were added. The mixture was stirred at 140 °C at 400 rpm using a 6-blade disk turbine blade (blade diameter 3 cm) under a nitrogen:hydrogen (volume ratio) of 1:0.43, and heated to 101 kPa for mixing. During the reaction, the fraction was continuously distilled into a fraction receiver connected to the flask. After 15 hours of reaction, 38.4 g of fraction was obtained, and 254.6 g of the reaction product was obtained. The obtained reaction product was quantified by GC. The yield of 2-pentyl-2-cyclopenten-1-one (3) and the production rate of 2-pentylcyclopentan-1-one (7) are shown in Table 6. The reaction product was filtered using a pressure filter, and the catalyst (5% Pd / C) was recovered.

[0228] [Example 12] The procedure was the same as in Example 11, except that instead of adding phosphate-supported activated carbon, 5% Pd / C, and sulfur powder, the catalyst recovered in Example 11 was used.

[0229] The yield of 2-pentyl-2-cyclopenten-1-one (3) and the production rate of 2-pentylcyclopentan-1-one (7) are shown in Table 6.

[0230] [Example 13] The procedure was the same as in Example 12, except that the catalyst recovered in Example 11 was replaced with the catalyst recovered in Example 12. The yield of 2-pentyl-2-cyclopenten-1-one (3) and the production rate of 2-pentylcyclopentan-1-one (7) are shown in Table 6.

[0231] [Example 14] The procedure was the same as in Example 13, except that the catalyst recovered in Example 13 was used instead of the catalyst recovered in Example 12. The yield of 2-pentyl-2-cyclopenten-1-one (3) and the production rate of 2-pentylcyclopentan-1-one (7) are shown in Table 6.

[0232] Table 6 confirms that using sulfur powder as a Group 16 element as a solid catalyst does not result in a decrease in yield even after three reuses.

[0233] [Table 6]

Claims

1. A process for producing a compound represented by the following general formula (I), which comprises isomerizing a compound represented by the following general formula (II) in the presence of molecular hydrogen and / or a hydrogen source, a platinum group metal catalyst, and an element of Group 16 (excluding oxygen) alone or a compound thereof. 【Chemical 24】 [In the formula, R 1 , R 2 , and R 4 simultaneously or independently represent a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms, R 3 represents a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms, or alternatively, R 1 and R 4 simultaneously or independently represent a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms, R 2 and R 3 together represent an alkanediyl group having 2 to 9 carbon atoms, or an alkanediyl group having 2 to 9 carbon atoms substituted with 1 to 2 alkyl groups having 1 to 5 carbon atoms. ]

2. The production method according to claim 1, wherein in the formula, R 2 and R 3 together represent an alkanediyl group having 2 to 9 carbon atoms.

3. The production method according to claim 1 or 2, wherein the metal of the platinum group metal catalyst is palladium or platinum.

4. The production method according to claim 1 or 2, wherein the metal of the platinum group metal catalyst is supported on carbon.

5. The production method according to claim 1 or 2, wherein the Group 16 element (excluding oxygen) alone or a compound thereof contains one or more selected from the group consisting of sulfur and sulfur compounds, selenium and selenium compounds, and tellurium and tellurium compounds.

6. The production method according to claim 5, wherein the sulfur compound is a compound having a sulfide group, a thiophene ring, or a thiol group.

7. The production method according to claim 1 or 2, wherein the Group 16 element (excluding oxygen) alone or a compound thereof contains sulfur.

8. Molecular hydrogen is mixed with an inert gas, The production method according to claim 1 or 2, wherein the inert gas is one or more selected from the group consisting of nitrogen, argon, and helium.

9. The production method according to claim 8, wherein the volume ratio of the molecular hydrogen to the inert gas (molecular hydrogen / inert gas) is 10 / 1 to 1 / 10.

10. The production method according to claim 1 or 2, wherein the usage amount of the Group 16 element (excluding oxygen) alone or a compound thereof is 0.1 mol% or more and 100 mol% or less with respect to the metal amount of the platinum group metal catalyst.

11. The production method according to claim 1 or 2, further comprising a step of dehydrating the compound represented by the general formula (III) in the presence of an acid to obtain the compound represented by the general formula (II). 【Chemical formula 25】 [In the formula, R 1 , R 2 and R 4 simultaneously or independently represent a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms, R 3 represents a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms, or or R 1 and R 4 each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms; R 2 and R 3 together represent an alkanediyl group having 2 to 9 carbon atoms or an alkanediyl group having 2 to 9 carbon atoms substituted with 1 to 2 alkyl groups having 1 to 5 carbon atoms. ]

12. The production method according to claim 11, wherein the acid contains a solid acid.

13. R 1 is an n-butyl group, R 2 and R 3 together are an alkanediyl group having 2 carbon atoms, and R 4 is a hydrogen atom, the production method according to claim 1 or 2.

14. The production method according to claim 1 or 2, wherein the compound represented by the general formula (III) is 2-(1-hydroxypentyl)-cyclopentan-1-one.

15. A method for producing a compound of formula (VII), comprising the following steps 1 and 2. Step 1: A compound represented by the following general formula (IV) is subjected to dehydration isomerization in the presence of molecular hydrogen and / or a hydrogen source, an acid, a platinum group metal catalyst, and a Group 16 element (excluding oxygen) alone or a compound thereof to obtain a compound represented by the following general formula (V). Step 2: A compound represented by the general formula (VII) is obtained by reacting the compound represented by the general formula (V) obtained in Step 1 with a malonic acid diester represented by the following general formula (VI) and then reacting with water. [Chemical formula 26] [wherein, R 1 and R 4represents, simultaneously or independently, a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkenyl group having 2 to 8 carbon atoms, R 2 ’ and R 3 ’ together represent an alkanediyl group having 2 to 9 carbon atoms or an alkanediyl group having 2 to 9 carbon atoms substituted with 1 to 2 alkyl groups having 1 to 5 carbon atoms, R 7 represents an alkyl group having 1 to 3 carbon atoms, and two Rs 7 may be the same or different. ]

16. R 1 is an n-butyl group, R 2 ’ and R 3 ’ together are an alkanediyl group having 2 carbon atoms, R 4 is a hydrogen atom, R 7 is a methyl group, and the production method according to claim 15.

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