Organic tertiary or quaternary ammonium salts as catalysts in the formation of γ,δ-unsaturated ketones

Abstract

The present invention relates to the preparation of γ,δ-unsaturated ketones from tertiary vinyl carbinols and vinyl ethers or ketals using organic tertiary or quaternary ammonium salts as catalysts.

Description

Detailed Description of the Invention

[0001] [Technical field] The present invention relates to the production of γ,δ-unsaturated ketones.

[0002] [Background of the invention] The γ,δ-unsaturated ketones of formula (I) are an important class of industrial chemicals and are central products in the synthesis of vitamins and fragrance ingredients, of particular importance. One viable synthetic route uses tertiary vinyl carbinol as the starting product.

[0003] G. Saucy et al., Helv. Chim. Acta 1967, 50, 2091-2095 and Helv. Chim. Acta 1967, 50, 2095-2100, disclose that phosphoric acid, sulfuric acid, or p-toluenesulfonic acid can be used as a catalyst for the reaction of tertiary vinyl carbinol with isopropenyl ether.

[0004] C. Wang et al., Green Chemistry 2009, 11, 6, 843-847, disclose the Zocie-Marbet reaction of tertiary propargyl alcohols with unsaturated ethers in the presence of ammonium ionic liquids. This reaction affords allene ketones, but these are not γ- or δ-unsaturated ketones.

[0005] However, the use of strong acids is disadvantageous because the handling of these chemicals is dangerous, special protective measures are used, and special and corrosion-resistant materials are required in the equipment used in the manufacturing process.

[0006] German Patent No. 19649564 discloses a variety of organophosphorus compounds as catalysts.

[0007] In WO 2010 / 046199A2, inorganic ammonium (NH4 +However, inorganic ammonium salts generally have poor solubility, and inorganic ammonium salts have been shown to reduce yields and selectivities, especially when used at concentrations below 1 mol %.

[0008] [Summary of the Invention] Therefore, the problem solved by the present invention is to provide a high yield and high selectivity process using a catalyst with suitable solubility in the absence of strong acids and corrosive conditions.

[0009] It has surprisingly been found that this problem can be solved by the method according to claim 1 and the mixture of reactants according to claim 17. Organic tertiary and quaternary ammonium salts have been found to be particularly well suited as catalysts for the reaction. Organic tertiary and quaternary ammonium salt catalysts having an anion containing a phosphorus atom bonded to at least one oxygen atom have been found to be particularly well suited.

[0010] Further aspects of the invention are the subject matter of further independent claims. Particularly preferred embodiments are the subject matter of the dependent claims. [Brief explanation of the drawings]

[0011] [Figure 1] 2-Methyl-3-buten-2-ol ("MBE") was mixed with 2.1 equivalents of isopropenyl methyl ether ("IPM") in the presence of the corresponding catalyst and stirred at a temperature of 150°C for a reaction time as shown in Table 1. The corresponding product, i.e., 6-methyl-5-hepten-2-one, was obtained in the yield and selectivity as shown in Table 1. [Figure 2] 3,7-Dimethylocta-1,6-dien-3-ol ("LL") was mixed with various equivalent amounts of isopropenyl methyl ether ("IPM") as shown in Table 2 in the presence of the corresponding catalyst in the amount shown in Table 2 and stirred at a temperature of 150°C for 16 hours. The corresponding product, i.e., 6,10-dimethylundeca-5,9-dien-2-one, was obtained in the yield and selectivity as shown in Table 2.

[0012] [Detailed Description of the Invention] In a first aspect, the present invention provides a γ,δ-unsaturated ketone of formula (I): [ka] a compound of formula (II) and a compound of formula (IIIa) or (IIIb) [ka] and in the presence of an organic tertiary or quaternary ammonium salt as a catalyst, During the ceremony, R 1 represents a methyl group or an ethyl group, R 2 represents a saturated or unsaturated, linear or branched or cyclic hydrocarbyl group having 1 to 46 C atoms, R 3 represents a methyl group or an ethyl group, R 4 represents H or a methyl group or an ethyl group, R 5 is a linear or branched chain C 1~10 represents an alkyl group, in particular a methyl or ethyl group, R 5’ and R 5’’ teeth, Either straight or branched chain C 1~10 represents an alkyl group, in particular a methyl or ethyl group, Or R 5’ and R 5’’ is a linear or branched chain C 1~10 together forming an alkylene group, in particular an ethylene or propylene group, and, The wavy line refers to a method of representing a carbon-carbon bond that is in either the Z or E configuration when connected to a carbon-carbon double bond.

[0013] For clarity, some terms used herein are defined as follows:

[0014] As used herein, "C x~y An "alkyl" group is an alkyl group containing x to y carbon atoms, i.e., for example, C 1~3 An alkyl group is an alkyl group containing 1 to 3 carbon atoms. An alkyl group may be straight-chain or branched. For example, -CH(CH3)-CH2-CH3 is considered a C4 alkyl group.

[0015] In this specification, when the same designation for a symbol or group occurs in more than one formula, the definition of the group or symbol given in connection with a particular formula also applies to other formulas containing the same designation.

[0016] As used herein, the term "independently of each other" in the context of substituents, moieties, or groups means that similarly designated substituents, moieties, or groups can exist simultaneously in the same molecule while having different meanings.

[0017] The term "organic" in the term "organic tertiary or quaternary ammonium salt" herein refers to the ammonium cation. Thus, "organic tertiary or quaternary ammonium salt" herein refers to any salt containing an organic tertiary or quaternary ammonium component. In contrast, NH4 + is considered an inorganic ammonium salt. Thus, for example, tetrabutylammonium chloride or triethylammonium bromide or tetrabutylammonium acetate are considered organic tertiary or quaternary ammonium salts, but, for example, ammonium sulfate ((NH4)2SO4) or ammonium acetate (CH3COONH4) are not considered organic tertiary or quaternary ammonium salts.

[0018] As used herein, any dotted line in a formula represents the bond by which a substituent is attached to the remainder of the molecule.

[0019] As used herein, all wavy lines, independent of one another, when connected to a carbon-carbon double bond, represent carbon-carbon bonds that are in either the Z or E configuration.

[0020] The compound of formula (II) can be converted to a compound of formula (IIIa) or (IIIb) in the presence of a catalyst (= "Cat") which is an organic tertiary or quaternary ammonium salt. [ka] React with either

[0021] [Compound of formula (II)] The compounds of formula (II) are known to those skilled in the art.

[0022] R 1 represents a methyl group or an ethyl group, preferably a methyl group.

[0023] R 2 represents a saturated or unsaturated, linear or branched or cyclic hydrocarbyl group having 1 to 46 C atoms, preferably a methyl group.

[0024] In a preferred embodiment, R 2 represents a group selected from the group consisting of formulae (R2-I), (R2-II), (R2-III) and (R2-IV). [ka]

[0025] The dotted line represents the bond by which a substituent of formula (R2-I), (R2-II), (R2-III) or (R2-IV) is attached to the remainder of the compound of formula (I) or formula (II). [ka] All double bonds represented by, independently of one another, represent either a carbon-carbon single bond or a carbon-carbon double bond. All wavy lines represented, independently of one another, represent carbon-carbon bonds in either the Z or E configuration when connected to a carbon-carbon double bond.

[0026] In the above formula, n represents 1, 2, 3 or 4, in particular 1 or 2.

[0027] In one preferred embodiment, R 2 represents either a group of formula (R2-I) or a group of formula (R2-II).

[0028] In another preferred embodiment, R 2 represents either a group of formula (R2-III) or a group of formula (R2-IV).

[0029] It is particularly preferred that the compound of formula (II) is selected from the group consisting of 2-methyl-3-buten-2-ol ("MBE"), 3-methyl-4-penten-3-ol ("EBE"), 3,7-dimethyl-1,6-octadien-3-ol (= linalool, "LL"), 3,7-dimethyl-1-octen-3-ol ("DMOE") and 3,7,11-trimethyl-1,6-dodecadien-3-ol (nerolidol, "NL"), in particular (6E)-3,7,11-trimethyl-1,6-dodecadien-3-ol (= E-nerolidol, "E-NL").

[0030] Even more preferably, the compound of formula (II) is 2-methyl-3-buten-2-ol ("MBE") or 3,7-dimethyl-1,6-octadien-3-ol (=linalool, "LL").

[0031] [Compound of formula (IIIa)] The compounds of formula (IIIa) are known to those skilled in the art.

[0032] In formula (IIIa), R 3 represents a methyl group or an ethyl group, and R 4represents H, a methyl group, or an ethyl group; R 5 is a linear or branched chain C 1~10 It represents an alkyl group, in particular a methyl or ethyl group.

[0033] Preferably, R 3 The group represents a methyl group.

[0034] Preferably, R 4 The group represents H.

[0035] Preferably, R 5 The group represents a methyl group.

[0036] The compound of formula (IIIa) is most preferably either isopropenyl methyl ether ("IPM") or isopropenyl ethyl ether ("IPE"), especially isopropenyl methyl ether ("IPM").

[0037] In the synthesis of compounds of formula (IIIa), mixtures of compounds of formula (IIIa) are also very often used in the reaction with compounds of formula (II). For example, in the case of butenyl methyl ether, a mixture of 2-methoxybut-1-ene, (E)-2-methoxybut-2-ene and (Z)-2-methoxybut-2-ene prepared from methanol and methyl ethyl ketone is often used.

[0038] [Compound of formula (IIIb)] The compounds of formula (IIIb) are known to those skilled in the art.

[0039] In formula (IIIb), R 3 represents a methyl group or an ethyl group, and R 4 represents H or a methyl group or an ethyl group.

[0040] R 5’ and R 5’’ In one embodiment, each of C is either linear or branched. 1~10 represents an alkyl group, in particular a methyl or ethyl group. 5’ and R5’’ is a linear or branched chain C 1~10 Together they form an alkylene group, in particular an ethylene or propylene group.

[0041] Preferably, R 3 The group represents a methyl group.

[0042] Preferably, R 4 The group represents H.

[0043] In one preferred embodiment, R 5’ =R 5’’ and especially R 5’ =R 5’’ = methyl or ethyl, more preferably R 5’ =R 5’’ =CH3.

[0044] In another preferred embodiment, R 5’ and R 5’’ together form an ethylene (CH2CH2) group or a propylene (CH2CH2CH2 or CH(CH3)CH2) group.

[0045] The compound of formula (IIIb) is most preferably either 2,2-dimethoxypropane, or 2,2-diethoxypropane, or 2,2-dimethyl-1,3-dioxolane, or 2,2,4-trimethyl-1,3-dioxolane, or 2,2-dimethyl-1,3-dioxane.

[0046] The compound of formula (IIIb) is most preferably either 2,2-dimethoxypropane or 2,2-diethoxypropane, especially 2,2-dimethoxypropane.

[0047] It is preferred to use compounds of formula (IIIa) rather than compounds of formula (IIIb).

[0048] [Organic tertiary or quaternary ammonium salts as catalysts] The reaction of the compound of formula (II) with the compound of formula (IIIa) or (IIIb) is carried out in the presence of an organic tertiary or quaternary ammonium salt as a catalyst.

[0049] In one preferred embodiment, the catalyst is an organic tertiary ammonium salt having a cation of formula (IV): [ka] and In the formula, R 20 , R 21 and R 22 are, independently of each other, linear or branched C 1~18 represents an alkyl group or a cycloalkyl group.

[0050] R 20 , R 21 and / or R 22 is a linear C 1~18 It preferably denotes an alkyl group.

[0051] R 20 , R 21 and / or R 22 More preferably, represents either a methyl group or an ethyl group.

[0052] R 20 =R 21 =R 22 It is more preferable that:

[0053] R 20 =R 21 =R 22 Particularly preferably = methyl or ethyl.

[0054] In another preferred embodiment, the catalyst is an organic tertiary ammonium salt having a cation of formula (V): [ka] and In the formula, R 30 , R 31, R 32 , R 33 and R 34 are independently H or straight or branched chain C 1~12 Alkyl group or C 5~12 cycloalkyl group.

[0055] R 30 =R 31 =R 32 =R 33 Preferably, R 30 =R 31 =R 32 =R 33 =H.

[0056] R 30 , R 31 , R 32 , R 33 and R 34 It is even more preferred that one of the groups is a methyl group.

[0057] R 34 It is also preferred that represents a methyl group or H, preferably H.

[0058] The most preferred tertiary ammonium compound of formula (V) is pyridinium or α-picolinium or β-picolinium or γ-picolinium, preferably pyridinium.

[0059] In another preferred embodiment, the catalyst is an organic quaternary ammonium salt having a cation of formula (VI): [ka] and In the formula, R 20 , R 21 , R 22 and R 23 are, independently of each other, linear or branched C 1~18 represents an alkyl group or a cycloalkyl group.

[0060] R20 , R 21 , R 22 and / or R 23 is a linear C 1~18 It is preferably an alkyl group.

[0061] R 20 , R 21 and / or R 22 More preferably, represents either a methyl group or an ethyl group.

[0062] R 20 =R 21 =R 22 =R 23 It is more preferable that:

[0063] R 20 =R 21 =R 22 =R 23 = methyl or butyl, preferably butyl.

[0064] Organic tertiary or quaternary ammonium salts can be readily formed from their corresponding tertiary amines by protonation, respectively, via alkylation.

[0065] The organic tertiary or quaternary ammonium salt used as the catalyst has an anion of preferably PO4 3- , HPO4 2- , H2PO4 - , P2O7 3- , HP2O7 2- and H3P2O7 - It has been found that particularly high yields and selectivities for the desired product of formula (I) are obtained when the compound contains a phosphorus atom bonded to at least one oxygen atom selected from the group consisting of:

[0066] It has been found that the reaction is preferably carried out when the molar ratio of the compound of formula (II) to the compound of formula (IIIa) or (IIIb) is in the range of 1:15 to 1:1.

[0067] When a compound of formula (IIIa) is used, the ratio is more preferably in the range of 1:5 to 1:2, even more preferably in the range of 1:3.5 to 1:2, most preferably in the range of 1:3 to 1:2, and particularly preferably in the range of 1:2.5 to 1:2.

[0068] When a compound of formula (IIIb) is used, the ratio is more preferably in the range of 1:10 to 1:2, even more preferably in the range of 1:8 to 1:3, and most preferably in the range of 1:8 to 1:5.

[0069] Furthermore, the amount of the organic tertiary or quaternary ammonium salt is in the range of 0.01 to 0.3 mol %, preferably in the range of 0.02 to 0.1 mol %, and more preferably in the range of 0.02 to 0.07 mol %, based on the amount of the compound of formula (II).

[0070] Surprisingly, it has been found that even when using less than 1 mol %, in particular less than 0.7 mol %, of the organic tertiary or quaternary ammonium salt catalyst, it can still be used even when the ratio of the compound of formula (II) to the compound of formula (IIIa) or (IIIb) is between 1:3 and 1:2, in particular 1:2.5 and 1:2, which significantly reduces the selectivity and / or yield of the compound of formula (I).

[0071] The reaction is preferably carried out at a temperature in the range of 100 to 170°C, more preferably in the range of 110 to 160°C, and most preferably in the range of 120 to 150°C.

[0072] The reaction is preferably carried out at a pressure in the range of 5 to 15 bar, more preferably at a pressure in the range of 8 to 12 bar.

[0073] The reaction can be carried out without a solvent or in the presence of an organic solvent. Preferably, the reaction is carried out without a solvent.

[0074] Even when the reaction is carried out in the absence of an organic solvent, the starting materials, the compound of formula (II) and the compound of formula (IIIa) or (IIIb), and the organic tertiary or quaternary ammonium salt, may still be provided in an organic solvent. Thus, the organic solvent may be present in an amount of up to 10% by weight, preferably up to 5% by weight, and more preferably up to 3% by weight, based on the total weight of the mixture of reactants.

[0075] If the reaction is carried out in an organic solvent, a polar aprotic organic solvent is preferred, for example an aliphatic ketone, such as acetone.

[0076] The above reaction has been found to provide compounds of formula (I) in high conversion, high yield and high selectivity.

[0077] In particular, it has been found that the compound of formula (I) is selected from the group consisting of 6-methyl-5-hepten-2-one, 6-methyl-5-octen-2-one, 6,10-dimethyl-5,9-undecadien-2-one, 6,10-dimethyl-5-undecen-2-one, 6,10,14-trimethylpentadeca-5,9-dien-2-one, 6,10,14-trimethylpentadeca-5,13-dien-2-one and 6,10,14-trimethyl-5,9,13-pentadeca-trien-2-one, and is preferably capable of producing 6-methyl-5-hepten-2-one or 6,10-dimethyl-5,9-undecadien-2-one.

[0078] The mixture of reactants itself, with or without organic solvent, is also an object of the present invention.

[0079] Thus, in a further aspect, the present invention provides a compound of formula (II): [ka] A compound of formula (IIIa) or (IIIb), [ka] and a reactant mixture containing a catalyst which is an organic tertiary or quaternary ammonium salt.

[0080] The compounds of formula (II) and compounds of formula (IIIa) or (IIIb), as well as the catalysts which are organic tertiary or quaternary ammonium salts, have already been fully described above.

[0081] [Example] The invention is further illustrated by the following non-limiting experiments.

[0082] [Experimental series 1] 2-Methyl-3-buten-2-ol ("MBE") was mixed with 2.1 equivalents of isopropenyl methyl ether ("IPM") in the presence of the corresponding catalyst and stirred at a temperature of 150°C for a reaction time as shown in Table 1. The corresponding product, i.e., 6-methyl-5-hepten-2-one, was obtained in the yield and selectivity as shown in Table 1 (see Figure 1).

[0083] [Table 1]

[0084] [Experimental series 2] 3,7-Dimethylocta-1,6-dien-3-ol ("LL") was mixed with various equivalent amounts of isopropenyl methyl ether ("IPM") as shown in Table 2 in the presence of the corresponding catalyst in the amount shown in Table 2 and stirred at a temperature of 150°C for 16 hours. The corresponding product, i.e., 6,10-dimethylundeca-5,9-dien-2-one, was obtained in the yield and selectivity as shown in Table 2 (see Figure 2).

[0085] [Table 2]

Claims

1. γ,δ-unsaturated ketones of formula (I) 【Chemistry 1】 a compound of formula (II) and a compound of formula (IIIa) or (IIIb) 【Chemistry 2】 in the presence of an organic tertiary or quaternary ammonium salt as a catalyst, During the ceremony, R １ represents a methyl group or an ethyl group, R ２ represents a saturated or unsaturated, linear or branched or cyclic hydrocarbyl group having 1 to 46 C atoms, R ３ represents a methyl group or an ethyl group, R ４ represents H or a methyl group or an ethyl group, R ５ is a linear or branched chain C １～１０ represents an alkyl group, R ５’ and R ５’’ teeth, Either straight or branched chain C １～１０ represents an alkyl group, or Or, R ５’ and R ５’’ is a linear or branched chain C １～１０ together form an alkylene group, and, the wavy line represents a carbon-carbon bond that, when connected to a carbon-carbon double bond, is in either the Z or E configuration; The catalyst is an organic tertiary ammonium salt having a cation of formula (IV) 【Transformation 3】 and wherein R 20 , R 21 and R 22 independently of one another represent a linear or branched C 1-18 alkyl or cycloalkyl group; or The catalyst is an organic tertiary ammonium salt having a cation of formula (V) 【Chemistry 4】 and wherein R 30 , R 31 , R 32 , R 33 and R 34 independently of one another represent either H or a linear or branched C 1-12 alkyl group or a C 5-12 cycloalkyl group; or The catalyst is an organic quaternary ammonium salt having a cation of formula (VI) 【Transformation 5】 and A method for preparing a γ,δ-unsaturated ketone of formula (I), wherein R 20 , R 21 , R 22 and R 23 independently of each other represent a linear or branched C 1-18 alkyl or cycloalkyl group.

2. R ２０ =R ２１ =R ２２ The method of claim 1, wherein

3. R ２０ =R ２１ =R ２２ 3. The method according to claim 1 or 2, characterized in that: = methyl or ethyl.

4. R ３０ =R ３１ =R ３２ =R ３３ The method of claim 1, wherein

5. R ３４ 5. The method according to claim 1 or 4, characterized in that represents a methyl group or H.

6. R ２０ =R ２１ =R ２２ =R ２３ The method of claim 1, wherein

7. R ２０ =R ２１ =R ２２ =R ２３ 7. The method according to claim 1 or 6, characterized in that: = methyl or butyl.

8. 8. The method according to claim 1, wherein the anion of the organic tertiary or quaternary ammonium salt comprises a phosphorus atom bonded to one or more oxygen atoms.

9. R １ 9. The method according to claim 1, wherein represents a methyl group.

10. 10. The process according to any one of claims 1 to 9, characterized in that the molar ratio of the compound of formula (II) to the compound of formula (IIIa) or (IIIb) is in the range of 1:15 to 1:

1.

11. 11. The method according to any one of claims 1 to 10, wherein the amount of the organic tertiary or quaternary ammonium salt is in the range of 0.01 to 0.3 mol %, based on the amount of the compound of formula (II).

12. R ２ Formula (R2-I), (R2-II), (R2-III) and (R2-IV) 【Transformation 6】 wherein the dotted line represents the bond by which a substituent of formula (R2-I), (R2-II), (R2-III) or (R2-IV) is attached to the remainder of the compound of formula (I) or formula (II); dotted line 【Transformation 7】 any double bond according to the formula: represents, independently of one another, either a carbon-carbon single bond or a carbon-carbon double bond; all wavy lines, independently of one another, when connected to a carbon-carbon double bond, represent carbon-carbon bonds that are in either the Z or E configuration; 12. The method according to claim 1, wherein n is selected from the group consisting of:

13. 13. The method of any one of claims 1 to 12, wherein the compound of formula (I) is selected from the group consisting of 6-methyl-5-hepten-2-one, 6-methyl-5-octen-2-one, 6,10-dimethyl-5,9-undecadien-2-one, 6,10-dimethyl-5-undecen-2-one, 6,10,14-trimethylpentadeca-5,9-dien-2-one, 6,10,14-trimethylpentadeca-5,13-dien-2-one and 6,10,14-trimethyl-5,9,13-pentadeca-trien-2-one.

14. A compound of formula (II), 【Transformation 8】 A compound of formula (IIIa) or (IIIb), 【Chemistry 9】 and a catalyst which is an organic tertiary or quaternary ammonium salt, During the ceremony, R １ represents a methyl group or an ethyl group, R ２ represents a saturated or unsaturated, linear or branched or cyclic hydrocarbyl group having 1 to 46 C atoms, R ３ represents a methyl group or an ethyl group, R ４ represents H or a methyl group or an ethyl group, R ５ is a linear or branched chain C １～１０ represents an alkyl group, R ５’ and R ５’’ teeth, Either straight or branched chain C １～１０ represents an alkyl group, or Or, R ５’ and R ５’’ is a linear or branched chain C １～１０ together form an alkylene group, The catalyst is an organic tertiary ammonium salt having a cation of formula (IV) 【Chemistry 10】 and wherein R 20 , R 21 and R 22 independently of one another represent a linear or branched C 1-18 alkyl or cycloalkyl group; or The catalyst is an organic tertiary ammonium salt having a cation of formula (V) 【Chemistry 11】 and wherein R 30 , R 31 , R 32 , R 33 and R 34 independently of one another represent either H or a linear or branched C 1-12 alkyl group or a C 5-12 cycloalkyl group; or The catalyst is an organic quaternary ammonium salt having a cation of formula (VI) 【Chemistry 12】 and A mixture of reactants wherein R 20 , R 21 , R 22 and R 23 independently of each other represent a straight or branched chain C 1-18 alkyl group or a cycloalkyl group.

Images