CA2041134A1 - Process for the preparation of linear 1,3-diketones - Google Patents
Process for the preparation of linear 1,3-diketonesInfo
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- CA2041134A1 CA2041134A1 CA002041134A CA2041134A CA2041134A1 CA 2041134 A1 CA2041134 A1 CA 2041134A1 CA 002041134 A CA002041134 A CA 002041134A CA 2041134 A CA2041134 A CA 2041134A CA 2041134 A1 CA2041134 A1 CA 2041134A1
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- c4alkyl
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C49/00—Ketones; Ketenes; Dimeric ketenes; Ketonic chelates
- C07C49/76—Ketones containing a keto group bound to a six-membered aromatic ring
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
- C07C45/61—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reactions not involving the formation of >C = O groups
- C07C45/67—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reactions not involving the formation of >C = O groups by isomerisation; by change of size of the carbon skeleton
- C07C45/68—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reactions not involving the formation of >C = O groups by isomerisation; by change of size of the carbon skeleton by increase in the number of carbon atoms
- C07C45/72—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reactions not involving the formation of >C = O groups by isomerisation; by change of size of the carbon skeleton by increase in the number of carbon atoms by reaction of compounds containing >C = O groups with the same or other compounds containing >C = O groups
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C319/00—Preparation of thiols, sulfides, hydropolysulfides or polysulfides
- C07C319/14—Preparation of thiols, sulfides, hydropolysulfides or polysulfides of sulfides
- C07C319/20—Preparation of thiols, sulfides, hydropolysulfides or polysulfides of sulfides by reactions not involving the formation of sulfide groups
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
- C07C45/45—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by condensation
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
- C07C45/45—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by condensation
- C07C45/455—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by condensation with carboxylic acids or their derivatives
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
- C07C45/61—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reactions not involving the formation of >C = O groups
- C07C45/67—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reactions not involving the formation of >C = O groups by isomerisation; by change of size of the carbon skeleton
- C07C45/76—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reactions not involving the formation of >C = O groups by isomerisation; by change of size of the carbon skeleton with the aid of ketenes
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C49/00—Ketones; Ketenes; Dimeric ketenes; Ketonic chelates
- C07C49/76—Ketones containing a keto group bound to a six-membered aromatic ring
- C07C49/782—Ketones containing a keto group bound to a six-membered aromatic ring polycyclic
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C49/00—Ketones; Ketenes; Dimeric ketenes; Ketonic chelates
- C07C49/76—Ketones containing a keto group bound to a six-membered aromatic ring
- C07C49/82—Ketones containing a keto group bound to a six-membered aromatic ring containing hydroxy groups
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C49/00—Ketones; Ketenes; Dimeric ketenes; Ketonic chelates
- C07C49/76—Ketones containing a keto group bound to a six-membered aromatic ring
- C07C49/82—Ketones containing a keto group bound to a six-membered aromatic ring containing hydroxy groups
- C07C49/835—Ketones containing a keto group bound to a six-membered aromatic ring containing hydroxy groups having unsaturation outside an aromatic ring
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
- Catalysts (AREA)
Abstract
Process for the preparation of linear 1,3-diketones There is disclosed a process for the preparation of 1,3-diketones of formula I
(I) wherein R1 and R2 are each independently of the other C1-C20alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, NO2, C1-C4alkyl and/or C1-C4alkoxy, C7-C9phenylalkyl or a radical of formula II
-A-X-R4 (II) wherein A is C1-C12alkylene, phenylene or phenylene which is substituted by halogen, hydroxy, NO2 C1-C4alkyl and/or C1-C4alkoxy, or is C1-C12alkylene which is substituted by hydroxy, halogen and/or alkoxy, X is oxygen or sulfur, and R4 is hydrogen, C1-C18alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, C1-C4alkyl, NO2 and/or C1-C4alkoxy, or is C7-C9phenylalkyl, and R3 is hydrogen, C1-C20alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, C1-C4alkyl, NO2 and/or C1-C4alkoxy, or is C7-C9phenylalkyl.
The process comprises carrying out a Claisen condensation of a ketone of formula III
(III) and an ester of formula IV
(IV) or
(I) wherein R1 and R2 are each independently of the other C1-C20alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, NO2, C1-C4alkyl and/or C1-C4alkoxy, C7-C9phenylalkyl or a radical of formula II
-A-X-R4 (II) wherein A is C1-C12alkylene, phenylene or phenylene which is substituted by halogen, hydroxy, NO2 C1-C4alkyl and/or C1-C4alkoxy, or is C1-C12alkylene which is substituted by hydroxy, halogen and/or alkoxy, X is oxygen or sulfur, and R4 is hydrogen, C1-C18alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, C1-C4alkyl, NO2 and/or C1-C4alkoxy, or is C7-C9phenylalkyl, and R3 is hydrogen, C1-C20alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, C1-C4alkyl, NO2 and/or C1-C4alkoxy, or is C7-C9phenylalkyl.
The process comprises carrying out a Claisen condensation of a ketone of formula III
(III) and an ester of formula IV
(IV) or
Description
2041~3~
Process for the preparation of linear 1.3-diketones The present invention relates to a process for the preparation of linear 1,3-diketones by a Claisen condensation of ketones with esters, in the presence of a hydride or alcoholate of an alkali metal or alkaline earth metal, and in a mixture of dimethyl sulfoxide and at least one organic solvent which is inert under the reaction conditions.
1,3-Diketones are disclosed in the literature as useful co-stabilisers for chlorinated polymers, especially polyvinyl chloride, which need to be protected against the harmful effects of heat and/or light. In addition, 1,3-diketones are important starting materials and intermediates for the synthesis of heterocycles. The Claisen condensation is commonly known in the art as a method of preparing 1,3-diketones and is described in numerous textbooks of organic chemistry, for example in Organikum, VEB Deutscher Verlag der Wissenschaften, Berlin (1969), pp. 580, 632, 658, J.B. Hendrickson, D.J. Cram, G.S. Harnmond, Organic Chemistry, McGraw-Hill S. 522, 524,525 or J. March, Advanced Organic Chemistry, J. Wiley & Sons (1985), pp. 437-39, 835.
The reaction for the preparation of diketones is normally carried out in an inert organic solvent in the presence of an alkali metal alcoholate as base. Thus, for example, the preparation of unsaturated ,B-diketones with an alkali metal alcoholate in diethyl ether is taught in US-A 3,004,932. Other publications disclose the use of alkali metal hydrides as bases for the Claisen condensation. For example, in J.P. Anselme, Org. Synth. Vol 32 (1967), 3716, dibenzoylmethane is prepared by a Claisen condensation using sodium hydride as base in dimethyl sulfoxide.
Cyclic ,~-diketones are prepared in DE-A 1 618 442 by a Claisen condensation with an alkali metal alcoholate in an at least equimolar amount of dimethyl sulfoxide and, if desired, a further inert organic solvent.
As large excesses of ketones and lengthy reaction times are necessary to obtain good yields in the known Claisen condensation reactions, interest exists in providing improved processes for carrying out this reaction. Moreover, the method employed hitherto of 204~L13~
isolating and purifying the synthesised diketones is complicated and troublesome. The provision of a simplified process would therefore be industrially useful.
Surprisingly, it has now been found that the reaction proceeds especially well by using a rnixture of dimethyl sulfoxide and a further organic solvent which is inert under the reaction conditions. The reaction time is shortened and a very high yield is obtained.
Specifically, the invention relates to a process for the preparation of linear 1,3-diketones of general formula I
O H O
Il 1 11 Rl--C--C--C--R2 (I) wherein Rl and R2 are each independently of the other C1-C20alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, NO2, Cl-C4alkyl and/or C1-C4alkoxy, or are C7-Cgphenylalkyl or a radical of formula II
-A-X-R4 (II) wherein A is C1-Cl2alkylene, phenylene or phenylene which is substituted by halogen, hydroxy, NO2, Cl-C4alkyl and/or C1-C4alkoxy, or is C1-Cl2alkylene which is substituted byhvdroxy, halogen and/or alkoxy, X is oxygen or sulfur, and R4 is hydrogen, C1-C18alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, Cl-C4alkyl, NO2 and/or C1-C4alkoxy, or is C7-Cgphenylalkyl, and R3 is hydrogen, C1-C20alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, Cl-C4alL~yl, NO2 and/or Cl-C4alkoxy, or is C7-Cgphenylalkyl, by a Claisen condensation of ketones of forrnula III
Rl--C--IH2 (III) 204113~
with esters of formula IV
R2--c--OR5 (IV) wherein R5 is Cl-C5alkyl, phenyl or phenyl which is substituted by halogen, Cl-C4alkyl or hydroxy;
or, if R2 in forrnula I is -(CH2)mOH, also with cyclic esters of formula V
o (c~c=o (V) in which m is 2 to 10, in the presence of a hydride of an alkali metal or alkaline earth metal or of a Cl-C5alcoholate of an alkali metal or alkaline earth metal as base, which process comprises carrying out the reaction in a mixture of dimethyl sulfoxide and at least one organic solvent which is inert under the reaction conditions.
Rl and R2 as Cl-C20alkyl may be linear or branched and are typically methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, n-heptyl, n-octyl, isooctyl, n-nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl or eicosyl, preferably Cl-Cl8alkyl, the most preferred meanings being methyl, isopentyl, n-nonyl, pentadecyl or heptadecyl.
Rl or R2 as substituted phenyl contains 1 to 3, preferably 1 or 2 substituents, preferably one substituent.
Rl and R2 as (C~-C4alkyl)phenyl may be phenyl which is substituted by 1 to 3, preferably by 1 or 2, alkyl groups, most preferably by methyl groups. Typical examples are tolyl, xylyl or mesityl.
Rl and R2 as halogen-substituted phenyl may be a phenyl ring which is substituted by one 204~13~
or more identical or different members selected from the group consisting of fluoro, chloro and bromo, preferably chloro or bromo, and are typically chlorophenyl or dlchlorophenyl.
Cl-C4Alkoxy is typically methoxy, ethoxy, propoxy or butoxy, and a correspondingly substituted phenyl group is typically methoxyphenyl.
Rl and R2 as C7-Cgphenylalkyl may be benzyl, phenylethyl, a-methylbenzyl, 3-phenylpropyl or a,a-dimethylbenzyl. Benzyl is preferred. R1 and R2 are preferably Cl-CIgalkyl, phenyl, (Cl-C4alkyl)phenyl or-A-X-R4.
"
A as C1-Cl2alkylene may by linear or branched, preferably linear, alkylene. Typical examples of such radicals may be formed by adding the suffix -ene to the radicals cited above as suitable for R1 and R2 as alkyl up to the corresponding number of carbon atoms.
C1-C6Alkylene is preferred, and n-propylene or n-pentylene are most preferred.
R4 as C1-Clgalkyl may be linear or branched alkyl as exemplified above in connection with R1 and R2 up to the corresponding number of carbon atoms.
R4 as substituted phenyl or C7-Cgphenylalkyl may have the same meanings as given for R
and R2.
R4 is preferably hydrogen, C1-C1galkyl or phenyl.
A as unsubstituted or substituted phenylene is preferably o- or p-phenylene, most preferably unsubstituted phenylene.
R3 as Cl-C20alkyl, substituted phenyl or C7-Cgphenylalkyl may have the same meanings as given for Rl and R2, and is preferably C1-C4alkyl.
R3 is preferably hydrogen or C1-C4alkyl, but is most preferably hydrogen.
Rs as Cl-Csalkyl may be methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl or isopentyl. More particularly, Rs is C1-C4alkyl and is most preferably methyl.
Rs as (Cl-C4alkyl)phenyl may have the same meanings as given for R1 and R2.
204~13~
The aLlcali metal hydride used is typically lithium hydride, sodium hydride or potassium hydride, more particularly sodium hydride or potassium hydride. Sodium hydride is most preferred.
Illustrative examples of aL~caline earth metal hydrides are magnesium hydride and calcium hydride. AL~ali metal hydrides are preferred.
Typical examples of Cl-CsaL~cali metal alcoholates are LiOCH3, NaOCH3, KOCH3, LiOC2H5, NaOC2Hs, KOC2H5, LiOn-C3H7 NaOn-C3H7, KOn-C3H7, LiOi-C3H7, NaOi-C3H7, KOi-C3H7, LiOn-C4Hg, NaOn-C4Hg, KOn-C4Hg, LiOi-C4Hg, NaOi-C4Hg, KOi-C4Hg, LiOtert-C4Hg, NaOtert-C4Hg, KOtert-C4Hg, LiOn-CsHIl, NaOn-C5H1l, KOn-CsHll, LiOi-CsHll, NaOi-CsHll, KOi-CsHll, LiOtert-CsH11, NaOtert-C5Hll, and KOtert-CsHl 1-Typical examples of corresponding aL~aline earth metal alcoholates are Mg(OCH3)2, Ca(OCH3)2, Mg(OC2Hs)2, Ca(OC2Hs)2, Mg(On-C3H7)2, Ca(On-C3H7)2. Mg(Oi-C3H7)2, Ca(Oi-C3H7)2, Mg(On-C4Hg)2, Ca(On-C4Hg)2, Mg(Otert-C4Hg)2, Ca(Otert-C4Hg)2, Mg(Oi-C4Hg)2, Ca(Oi-C4Hg)2, Mg(On-C5HI1)2, Ca(On-CsHI1)2, Mg(Oi-C5H")2, Ca(Oi-CsH~l)2, Mg(Otert-CsHll)2, Ca(Otert-C5Hll)2. Magnesium alcoholates are preferred.
It is preferred tO use alkali metal alcoholates, more particularly sodium alcoholates such as NaOCH3, NaOC2Hs and NaOtert-C4Hg, most preferably NaOCH3 and NaOtert-C4Hg.
Organic solvents which are inert under the reaction conditions are typically linear or cyclic ethers, aliphatic or aromatic hydrocarbons, or cyclic or linear amides.
Linear or cyclic ethers may be mono-, di-, tri- or polyethers.
Illustrative examples of such ethers are: diethyl ether, diisopropyl ether, methyl tert-butyl ether, dibutyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, tetrahydropyran, dioxane or dioxolane. Cyclic ethers and higher linear ethers (for example those containing from S carbon atoms) are preferred, preferably dioxane, diethylene glycol dimethyl ether, tetrahydrofuran or methyl tert-butyl ether.
Mixtures of these solvents may also be used.
2041~3~
Aliphatic hydrocarbons which may be suitably be used are pentane, hexane, heptane, octane, cyclohexane, decalin, petroleum ether or mixtures thereof. Aromatic hydrocarbons which are conveniently used are typically benzene, toluene or xylene. Toluene ispreferred.
A suitable cyclic or linear amide is N-methyl-pyrrolidone.
Preferred inert organic solvents are dioxane, tetrahydrofuran, diethylene glycol dimethyl ether, methyl tert-butyl ether, toluene or N-methylpyIrolidone.
Particular interest attaches to the preparation of compounds of formula I, wherein Rl and R2 are each independently of the other Cl-C20alkyl, phenyl, (Cl-C4alkyl)phenyl or a radical of formula II, A is Cl-C6alkylene, R4 is hydrogen, Cl-CI8alkyl, phenyl or (Cl-C4alkyl)phenyl, and R3 is hydrogen and Cl-C4alkyl.
Preferred compounds of formula I are those wherein Rl and R2 are each independently of the other Cl-CI8alkyl, phenyl or a radical of formula II, R4 is hydrogen, phenyl or Cl-CIgalkyl, and R3 is hydrogen.
The key feature of the invention consists in the use, in the above described process, of a mixture of dimethyl sulfoxide and at least one organic solvent which is inert under the reaction conditions. It is preferred to use mixtures containing typically 10-80 %, preferably 10-60 % and, most preferably, 15-50 %, of dimethyl sulfoxide. Mixtures containing 20-70 %, typically 30-60 %, of dimethyl sulfoxide are also useful.
Solvent mixtures which do not contain dimethyl formamide are preferred. The reaction mixture may also contain minor amounts of the alcohol corresponding to the respective alkali metal or alkaline earth metal alcoholate.
The process of this invention is conveniendy carried out in the temperature range from -20 to +70C, preferably from -5 to +40C.
Process for the preparation of linear 1.3-diketones The present invention relates to a process for the preparation of linear 1,3-diketones by a Claisen condensation of ketones with esters, in the presence of a hydride or alcoholate of an alkali metal or alkaline earth metal, and in a mixture of dimethyl sulfoxide and at least one organic solvent which is inert under the reaction conditions.
1,3-Diketones are disclosed in the literature as useful co-stabilisers for chlorinated polymers, especially polyvinyl chloride, which need to be protected against the harmful effects of heat and/or light. In addition, 1,3-diketones are important starting materials and intermediates for the synthesis of heterocycles. The Claisen condensation is commonly known in the art as a method of preparing 1,3-diketones and is described in numerous textbooks of organic chemistry, for example in Organikum, VEB Deutscher Verlag der Wissenschaften, Berlin (1969), pp. 580, 632, 658, J.B. Hendrickson, D.J. Cram, G.S. Harnmond, Organic Chemistry, McGraw-Hill S. 522, 524,525 or J. March, Advanced Organic Chemistry, J. Wiley & Sons (1985), pp. 437-39, 835.
The reaction for the preparation of diketones is normally carried out in an inert organic solvent in the presence of an alkali metal alcoholate as base. Thus, for example, the preparation of unsaturated ,B-diketones with an alkali metal alcoholate in diethyl ether is taught in US-A 3,004,932. Other publications disclose the use of alkali metal hydrides as bases for the Claisen condensation. For example, in J.P. Anselme, Org. Synth. Vol 32 (1967), 3716, dibenzoylmethane is prepared by a Claisen condensation using sodium hydride as base in dimethyl sulfoxide.
Cyclic ,~-diketones are prepared in DE-A 1 618 442 by a Claisen condensation with an alkali metal alcoholate in an at least equimolar amount of dimethyl sulfoxide and, if desired, a further inert organic solvent.
As large excesses of ketones and lengthy reaction times are necessary to obtain good yields in the known Claisen condensation reactions, interest exists in providing improved processes for carrying out this reaction. Moreover, the method employed hitherto of 204~L13~
isolating and purifying the synthesised diketones is complicated and troublesome. The provision of a simplified process would therefore be industrially useful.
Surprisingly, it has now been found that the reaction proceeds especially well by using a rnixture of dimethyl sulfoxide and a further organic solvent which is inert under the reaction conditions. The reaction time is shortened and a very high yield is obtained.
Specifically, the invention relates to a process for the preparation of linear 1,3-diketones of general formula I
O H O
Il 1 11 Rl--C--C--C--R2 (I) wherein Rl and R2 are each independently of the other C1-C20alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, NO2, Cl-C4alkyl and/or C1-C4alkoxy, or are C7-Cgphenylalkyl or a radical of formula II
-A-X-R4 (II) wherein A is C1-Cl2alkylene, phenylene or phenylene which is substituted by halogen, hydroxy, NO2, Cl-C4alkyl and/or C1-C4alkoxy, or is C1-Cl2alkylene which is substituted byhvdroxy, halogen and/or alkoxy, X is oxygen or sulfur, and R4 is hydrogen, C1-C18alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, Cl-C4alkyl, NO2 and/or C1-C4alkoxy, or is C7-Cgphenylalkyl, and R3 is hydrogen, C1-C20alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, Cl-C4alL~yl, NO2 and/or Cl-C4alkoxy, or is C7-Cgphenylalkyl, by a Claisen condensation of ketones of forrnula III
Rl--C--IH2 (III) 204113~
with esters of formula IV
R2--c--OR5 (IV) wherein R5 is Cl-C5alkyl, phenyl or phenyl which is substituted by halogen, Cl-C4alkyl or hydroxy;
or, if R2 in forrnula I is -(CH2)mOH, also with cyclic esters of formula V
o (c~c=o (V) in which m is 2 to 10, in the presence of a hydride of an alkali metal or alkaline earth metal or of a Cl-C5alcoholate of an alkali metal or alkaline earth metal as base, which process comprises carrying out the reaction in a mixture of dimethyl sulfoxide and at least one organic solvent which is inert under the reaction conditions.
Rl and R2 as Cl-C20alkyl may be linear or branched and are typically methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, n-heptyl, n-octyl, isooctyl, n-nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl or eicosyl, preferably Cl-Cl8alkyl, the most preferred meanings being methyl, isopentyl, n-nonyl, pentadecyl or heptadecyl.
Rl or R2 as substituted phenyl contains 1 to 3, preferably 1 or 2 substituents, preferably one substituent.
Rl and R2 as (C~-C4alkyl)phenyl may be phenyl which is substituted by 1 to 3, preferably by 1 or 2, alkyl groups, most preferably by methyl groups. Typical examples are tolyl, xylyl or mesityl.
Rl and R2 as halogen-substituted phenyl may be a phenyl ring which is substituted by one 204~13~
or more identical or different members selected from the group consisting of fluoro, chloro and bromo, preferably chloro or bromo, and are typically chlorophenyl or dlchlorophenyl.
Cl-C4Alkoxy is typically methoxy, ethoxy, propoxy or butoxy, and a correspondingly substituted phenyl group is typically methoxyphenyl.
Rl and R2 as C7-Cgphenylalkyl may be benzyl, phenylethyl, a-methylbenzyl, 3-phenylpropyl or a,a-dimethylbenzyl. Benzyl is preferred. R1 and R2 are preferably Cl-CIgalkyl, phenyl, (Cl-C4alkyl)phenyl or-A-X-R4.
"
A as C1-Cl2alkylene may by linear or branched, preferably linear, alkylene. Typical examples of such radicals may be formed by adding the suffix -ene to the radicals cited above as suitable for R1 and R2 as alkyl up to the corresponding number of carbon atoms.
C1-C6Alkylene is preferred, and n-propylene or n-pentylene are most preferred.
R4 as C1-Clgalkyl may be linear or branched alkyl as exemplified above in connection with R1 and R2 up to the corresponding number of carbon atoms.
R4 as substituted phenyl or C7-Cgphenylalkyl may have the same meanings as given for R
and R2.
R4 is preferably hydrogen, C1-C1galkyl or phenyl.
A as unsubstituted or substituted phenylene is preferably o- or p-phenylene, most preferably unsubstituted phenylene.
R3 as Cl-C20alkyl, substituted phenyl or C7-Cgphenylalkyl may have the same meanings as given for Rl and R2, and is preferably C1-C4alkyl.
R3 is preferably hydrogen or C1-C4alkyl, but is most preferably hydrogen.
Rs as Cl-Csalkyl may be methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl or isopentyl. More particularly, Rs is C1-C4alkyl and is most preferably methyl.
Rs as (Cl-C4alkyl)phenyl may have the same meanings as given for R1 and R2.
204~13~
The aLlcali metal hydride used is typically lithium hydride, sodium hydride or potassium hydride, more particularly sodium hydride or potassium hydride. Sodium hydride is most preferred.
Illustrative examples of aL~caline earth metal hydrides are magnesium hydride and calcium hydride. AL~ali metal hydrides are preferred.
Typical examples of Cl-CsaL~cali metal alcoholates are LiOCH3, NaOCH3, KOCH3, LiOC2H5, NaOC2Hs, KOC2H5, LiOn-C3H7 NaOn-C3H7, KOn-C3H7, LiOi-C3H7, NaOi-C3H7, KOi-C3H7, LiOn-C4Hg, NaOn-C4Hg, KOn-C4Hg, LiOi-C4Hg, NaOi-C4Hg, KOi-C4Hg, LiOtert-C4Hg, NaOtert-C4Hg, KOtert-C4Hg, LiOn-CsHIl, NaOn-C5H1l, KOn-CsHll, LiOi-CsHll, NaOi-CsHll, KOi-CsHll, LiOtert-CsH11, NaOtert-C5Hll, and KOtert-CsHl 1-Typical examples of corresponding aL~aline earth metal alcoholates are Mg(OCH3)2, Ca(OCH3)2, Mg(OC2Hs)2, Ca(OC2Hs)2, Mg(On-C3H7)2, Ca(On-C3H7)2. Mg(Oi-C3H7)2, Ca(Oi-C3H7)2, Mg(On-C4Hg)2, Ca(On-C4Hg)2, Mg(Otert-C4Hg)2, Ca(Otert-C4Hg)2, Mg(Oi-C4Hg)2, Ca(Oi-C4Hg)2, Mg(On-C5HI1)2, Ca(On-CsHI1)2, Mg(Oi-C5H")2, Ca(Oi-CsH~l)2, Mg(Otert-CsHll)2, Ca(Otert-C5Hll)2. Magnesium alcoholates are preferred.
It is preferred tO use alkali metal alcoholates, more particularly sodium alcoholates such as NaOCH3, NaOC2Hs and NaOtert-C4Hg, most preferably NaOCH3 and NaOtert-C4Hg.
Organic solvents which are inert under the reaction conditions are typically linear or cyclic ethers, aliphatic or aromatic hydrocarbons, or cyclic or linear amides.
Linear or cyclic ethers may be mono-, di-, tri- or polyethers.
Illustrative examples of such ethers are: diethyl ether, diisopropyl ether, methyl tert-butyl ether, dibutyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, tetrahydropyran, dioxane or dioxolane. Cyclic ethers and higher linear ethers (for example those containing from S carbon atoms) are preferred, preferably dioxane, diethylene glycol dimethyl ether, tetrahydrofuran or methyl tert-butyl ether.
Mixtures of these solvents may also be used.
2041~3~
Aliphatic hydrocarbons which may be suitably be used are pentane, hexane, heptane, octane, cyclohexane, decalin, petroleum ether or mixtures thereof. Aromatic hydrocarbons which are conveniently used are typically benzene, toluene or xylene. Toluene ispreferred.
A suitable cyclic or linear amide is N-methyl-pyrrolidone.
Preferred inert organic solvents are dioxane, tetrahydrofuran, diethylene glycol dimethyl ether, methyl tert-butyl ether, toluene or N-methylpyIrolidone.
Particular interest attaches to the preparation of compounds of formula I, wherein Rl and R2 are each independently of the other Cl-C20alkyl, phenyl, (Cl-C4alkyl)phenyl or a radical of formula II, A is Cl-C6alkylene, R4 is hydrogen, Cl-CI8alkyl, phenyl or (Cl-C4alkyl)phenyl, and R3 is hydrogen and Cl-C4alkyl.
Preferred compounds of formula I are those wherein Rl and R2 are each independently of the other Cl-CI8alkyl, phenyl or a radical of formula II, R4 is hydrogen, phenyl or Cl-CIgalkyl, and R3 is hydrogen.
The key feature of the invention consists in the use, in the above described process, of a mixture of dimethyl sulfoxide and at least one organic solvent which is inert under the reaction conditions. It is preferred to use mixtures containing typically 10-80 %, preferably 10-60 % and, most preferably, 15-50 %, of dimethyl sulfoxide. Mixtures containing 20-70 %, typically 30-60 %, of dimethyl sulfoxide are also useful.
Solvent mixtures which do not contain dimethyl formamide are preferred. The reaction mixture may also contain minor amounts of the alcohol corresponding to the respective alkali metal or alkaline earth metal alcoholate.
The process of this invention is conveniendy carried out in the temperature range from -20 to +70C, preferably from -5 to +40C.
2()~113~
The reaction times of the above described Claisen condensation may vary within a wide range, but are normally from 0.5 to 5.0 hours.
The possibility of a simplified working up after the reaction is also important. This working up consists in isolating the alkali metal salt or alkaline earth metal salt of the diketone direct from the reaction solution, washing said salt, and subsequently obtaining the pure diketone after hydrolysis with a dilute acid. Suitable acids are typically acetic acid, formic acid, phosphoric acid, hydrochloric acid and sulfuric acid, preferably hydrochloric acid and sulfuric acid.
As mentioned at the outset, the linear 1,3-diketones obtainable by the process of this invention are useful co-stabilisers for chlorinated polymers which need to be protected against the harmful effect of heat and/or light. Consequently an interest exists in preparing these diketones in high yield by the simplest possible methods with a low energyconsumption.
The process of this invention opens up an indus~ially particulariy advantageous and economic route to the preparation of these compounds.
An important advantage of the process of this invention is that relatively low reaction temperatures are required for carrying it out. The resultant energy-saving is a major aspect of the industrial application of the process. The process can, for example, be carried out in the temperature range from -20 to +70C, preferably from -5 to +40C. An increase in the reaction temperature does not necessarily lead to an increase in yield. In the prior art processes, the use of an up to 100 % excess of ketone is necessary to obtain good yields. A
particular technical advantage of the process of the invention therefore also resides in the possibility afforded of reducing the excess of educt and base compared with the prior art processes, thereby diminishing the waste disposal problems. The process of the invention thus also makes it possible to obtain high yields using approximately stoichiometric amounts or small excesses of ester. The ester component and/or base are conveniently added in an amount of 0.5-1.5 mol, preferably 0.65-1.25 mol, most preferably 0.9-1.2 mol, based on 1 mol of ketone.
The reaction is advantageously carried out, for example, by charging the base in the solvent to the reactor and adding the ester and ketone components in succession or simultaneously. Conventional operations, such as stirring the reaction mixture, are useful.
A preferred embodirnent of the process of the invention also comprises a simplified means of working up the reaction product, which does not - as hitherto known - absolutely need to be hydrolysed in the reaction solution and then extracted with the aid of organic solvents, but is isolated from the reaction solution in the form of the precipitated aLkali metal salt or aL~caline earth metal salt (if necessary after removal of at least a portion of the solvent and, if desired, after addition of a solvent in which the salt is insoluble), washed, and the pure isolated salt is then hydrolysed. One advantage is that the organic solvent is not contarninated with water and can be readily reused.
In addition, this method of working up gives reaction products of high purity, as organic by-products can be removed together with the solvent, whereas these products, when working up by extraction, are extracted together with the desired reaction product and contaminate it.
As known to the skilled person, some or all of the compounds of forrnula I can naturally be obtained in the tautomeric forms according to the equilibrium O OH O H O OH O
R~ --C = C--R2 ~ R~--C--C--C--R2 ~ R~ --C--R2 The invention is illustrated in more detail by the following Examples in which, as well as throughout the description and claims, parts and percentages are by weight, unless otherwise stated.
Example 1: 1,3-Diphenylpropane-1,3-dione (dibenzoylmethane) ~} C - CH2- C ~3 In a 0.51 Sovirel flask (double-walled reactor) fitted with stirrer, thermometer, dropping funnel and reflux condenser with bubble counter, 100 g of anhydrous dimethyl sulfoxide (DMSO) and 100 g of tetrahydrofuran and 10 g of sodium hydride (80 % in paraffin oil) 204~3~
acetophenone is added dropwise over 6Q minutes at 5-10C. When the addition is complete, the mixture is stirred for 10 minutes at 5C, then warmed to 30C and transferred to a l litre single-necked flask. The low boiling fractions are removed by distillation on a rotary evaporator, and the residue (203 g) is dissolved in 800 ml of ice-water. After acidification with 30 g of 50 % sulfuric acid and stirring for 10 minutes, the precipitated crystals are filtered with suction, washed with water and dried to constant weight.
Yield: 63.6 g ; 94.5 % of theory of pale yellow crystals with a melting point of72-75C.
Purity of the dibenzoylmethane according to gas chromatography: 98.2 %.
Example 2: 1,3-Diphenylpropane- 1,3-dione (dibenzoylmethane) ~ C - CH2- C ~
100 g of anhydrous dimethyl sulfoxide, 100 g of diethylene glycol dimethyl ether, 6 g of absolute methanol and 18 g of sodium methylate (97 %) are charged to an apparatus as described in Example 1. A mixture of 45 g of methyl benzoate and 36 g of acetophenone are added dropwise to this mixture at 25 C over 4~ minutes. After this addition, the reaction mixture is stirred for 2 hours at 30C and the solvent is removed by vacuum distillation at a temperature of < 60 C. The residue is diluted with 150 g of methyl tert-butyl ether, cooled to 0C and filtered. The filter cake is washed twice with methyl tert-butyl ether. The pale grey solid is thereafter taken up in dilute hydrochloric acid and stirred.
The product is isolated by filtration and dried to constant weight.
Yield: 61.3 g _ 91.1 % of theory of white to pale yellow crystals with a melting point of 72-75C.
Z04~134;
Example 3: 1 -Phenylbutane- 1 ,3-dione ~C-CH2-8--CH3 The procedure of Example 1 is repeated, using in place of acetophenone 17.4 g of acetone and increasing the amount of solvent from 100 g to 150 g of dimethyl sulfoxide/tetra-hydrofuran.
Yield: 42.6 g _ 87.~ % of theory of a yellow crystalline powder with a melting point of 52-53C.
The NMR spectrum confirms that a mixture of 14 % of CH3--C - CH2- 8 o and 86 % of CH3--C = CH- C ~ is obtained.
OH
Example 4: 6-Methyl-l-phenylheptane-1,3-dione C - CH2- C ~ CH2~2CH~CH
Yhe procedure as described in Example 1 is repeated, replacing acetophenone with 34.5 g of 5-methyl-2-hexanone.
Working up after acidification of the reaction mixture with sulfuric acid is effected by extracting the aqueous solution with 2 x 100 ml of dichloromethane, then drying the extract over sodium sulfate, stripping off the solvent on a rotary evaporator and purifying the residue by distillation.
Yield: 52.8 g _ 80.6 % of theory of a yellow fluid with a boiling point of 2041i3~
98-100C/0.2 mbar and a refractive index nD : 1.5505.
Example 5: l-Phenyldodecane-l ,3-dione ~ C--CH2- C ~ CH2~8 CH3 The procedure as described in Example 1 is repeated, replacing acetophenone with 51.0 g of 2-undecanone.
Working up is as described in Example 4.
Yield: 74.6 g _ 90.7 % of theory of a colourless fluid with a boiling point of 140-42C/0.25 mbar and a melting point of 36-37C.
Example 6: 1 -Phenyl-6-n-dodecylthiohexane- 1 ,3-dione ~ C--CH2- C ~ CH2~3 S-n-C1 2H25 The procedure as described in Example 1 is repeated, but using 24 g of acetophenone and replacing methyl benzoate and sodium hydride with 66.6 g of methyl n-dodecylthio-butyrate and 21.2 g of sodium tert-butylate. Tetrahydrofuran is replaced by the same amount of toluene and the reaction temperature is 0C.
Yield after recrystallisation from isopropanol/water: 55.7 g _ 71.4 % of theory of white crystals with a melting point of 44C.
Example 7: 1-Phenyl-6-phenylthio-hexan-1 ,3-dion ~ C--CH2- C ~ CH2~3 S ~=3 Z04~3~
The procedure as described in Example 1 is repeated, using 18 g of acetophenone and 4.9 g of sodium hydride and replacing methyl benzoate with 34.7 g of methyl n-phenylthiobutyrate. Working up is effected as described in Example 4.
Yield: 33.4 g _ 74.4 % of theory of a yellow fluid with a boiling point of 178-82C/0.13 mbar and a refractive index nD0: 1.6185.
Example 8: 8-Hydroxy-l-phenyloctane-1,3-dione O O
~C - CH2- C ~ CH2t OH
A 0.5 1 Sovirel flask (double-walled reactor) fitted with stirrer, thermometer, separating funnel and distillation receiver is charged, under nitrogen, with 99.0 g of sodium methylate solution (30 % solution in methanol) and 117 g of dimethyl sulfoxide. Ca. 62 g of methanol are distilled from this solution, and the resultant suspension is cooled. Then 100 g of N-methylpyrrolidone are added at 30C and the batch is cooled to 0C. At this temperature, a solution of 60.0 g of acetophenone, 62.8 g of ~-caprolactone and 17.0 g of N-methylpyrrolidone are added over 1 hour. The mixture is stirred for 30 minutes at 0C
and for 2 hours at 20C. At a sump temperature of <70C, ca. 120 g of solvent are distilled from the product solution. After cooling to 30C, 300 ml of water are added to the residue.
The solution is extracted with 3 x 70 ml of xylene, the aqueous phase is diluted with water to 1200 ml, and the pH is then adjusted to 5.5 with ca. 28 ml of 50 % sulfuric acid. The precipitated product is isolated by filtration, washed on the filter with 100 ml of water and dAed to constant weight under vacuum at ca. 30C.
Yield: 85.0 g ; 72.6 % of theory of slightly yellowish crystals with a melting point of 46-48C.
Purity according to gas chromatography: 97.3 %.
Example 9: 6-Hydroxy- 1 -phenylhexane- 1,3-dione o O
C-CH2-CtCH2t30H
60.0 g of acetophenone, 47.4 g of butyrolactone and 99.0 g of sodium methylate (30 %
solution in methanol) are reacted in the same manner as described in Example 8. After working up as described in Example 8, the product precipitates from the mother solution after several hours. The precipitate is isolated by f Itration, washed with water and dried to constant weight under vacuum at ca. 30C.
Yield: 70.0 g _ 68 % of theory of yellow crystals with a melting point of 35C.
Example 10: 8-Hydroxy- 1 -phenyloctane- 1,3-dione O O
ll ll ,~C - CH2- C ~ CH2t OH
An apparatus as described in Example 8 is charged with 30.8 g of sodium methylate (97 %), 117.0 g of DMSO and 117.0 g of dioxane and the mixture is cooled to 0C. At this temperature, a solution of 61.3 g of acetophenone, 57.7 g of ~-caprolactone and 17.0 g of dioxane are added, with stirring, over I hour. Stirring is continued for 30 minutes at 0C
and then for 2 hours at 20C. Subsequently ca. 220 g of solvent are distilled from the reaction mixture at 70C and under reduced pressure.
The reaction times of the above described Claisen condensation may vary within a wide range, but are normally from 0.5 to 5.0 hours.
The possibility of a simplified working up after the reaction is also important. This working up consists in isolating the alkali metal salt or alkaline earth metal salt of the diketone direct from the reaction solution, washing said salt, and subsequently obtaining the pure diketone after hydrolysis with a dilute acid. Suitable acids are typically acetic acid, formic acid, phosphoric acid, hydrochloric acid and sulfuric acid, preferably hydrochloric acid and sulfuric acid.
As mentioned at the outset, the linear 1,3-diketones obtainable by the process of this invention are useful co-stabilisers for chlorinated polymers which need to be protected against the harmful effect of heat and/or light. Consequently an interest exists in preparing these diketones in high yield by the simplest possible methods with a low energyconsumption.
The process of this invention opens up an indus~ially particulariy advantageous and economic route to the preparation of these compounds.
An important advantage of the process of this invention is that relatively low reaction temperatures are required for carrying it out. The resultant energy-saving is a major aspect of the industrial application of the process. The process can, for example, be carried out in the temperature range from -20 to +70C, preferably from -5 to +40C. An increase in the reaction temperature does not necessarily lead to an increase in yield. In the prior art processes, the use of an up to 100 % excess of ketone is necessary to obtain good yields. A
particular technical advantage of the process of the invention therefore also resides in the possibility afforded of reducing the excess of educt and base compared with the prior art processes, thereby diminishing the waste disposal problems. The process of the invention thus also makes it possible to obtain high yields using approximately stoichiometric amounts or small excesses of ester. The ester component and/or base are conveniently added in an amount of 0.5-1.5 mol, preferably 0.65-1.25 mol, most preferably 0.9-1.2 mol, based on 1 mol of ketone.
The reaction is advantageously carried out, for example, by charging the base in the solvent to the reactor and adding the ester and ketone components in succession or simultaneously. Conventional operations, such as stirring the reaction mixture, are useful.
A preferred embodirnent of the process of the invention also comprises a simplified means of working up the reaction product, which does not - as hitherto known - absolutely need to be hydrolysed in the reaction solution and then extracted with the aid of organic solvents, but is isolated from the reaction solution in the form of the precipitated aLkali metal salt or aL~caline earth metal salt (if necessary after removal of at least a portion of the solvent and, if desired, after addition of a solvent in which the salt is insoluble), washed, and the pure isolated salt is then hydrolysed. One advantage is that the organic solvent is not contarninated with water and can be readily reused.
In addition, this method of working up gives reaction products of high purity, as organic by-products can be removed together with the solvent, whereas these products, when working up by extraction, are extracted together with the desired reaction product and contaminate it.
As known to the skilled person, some or all of the compounds of forrnula I can naturally be obtained in the tautomeric forms according to the equilibrium O OH O H O OH O
R~ --C = C--R2 ~ R~--C--C--C--R2 ~ R~ --C--R2 The invention is illustrated in more detail by the following Examples in which, as well as throughout the description and claims, parts and percentages are by weight, unless otherwise stated.
Example 1: 1,3-Diphenylpropane-1,3-dione (dibenzoylmethane) ~} C - CH2- C ~3 In a 0.51 Sovirel flask (double-walled reactor) fitted with stirrer, thermometer, dropping funnel and reflux condenser with bubble counter, 100 g of anhydrous dimethyl sulfoxide (DMSO) and 100 g of tetrahydrofuran and 10 g of sodium hydride (80 % in paraffin oil) 204~3~
acetophenone is added dropwise over 6Q minutes at 5-10C. When the addition is complete, the mixture is stirred for 10 minutes at 5C, then warmed to 30C and transferred to a l litre single-necked flask. The low boiling fractions are removed by distillation on a rotary evaporator, and the residue (203 g) is dissolved in 800 ml of ice-water. After acidification with 30 g of 50 % sulfuric acid and stirring for 10 minutes, the precipitated crystals are filtered with suction, washed with water and dried to constant weight.
Yield: 63.6 g ; 94.5 % of theory of pale yellow crystals with a melting point of72-75C.
Purity of the dibenzoylmethane according to gas chromatography: 98.2 %.
Example 2: 1,3-Diphenylpropane- 1,3-dione (dibenzoylmethane) ~ C - CH2- C ~
100 g of anhydrous dimethyl sulfoxide, 100 g of diethylene glycol dimethyl ether, 6 g of absolute methanol and 18 g of sodium methylate (97 %) are charged to an apparatus as described in Example 1. A mixture of 45 g of methyl benzoate and 36 g of acetophenone are added dropwise to this mixture at 25 C over 4~ minutes. After this addition, the reaction mixture is stirred for 2 hours at 30C and the solvent is removed by vacuum distillation at a temperature of < 60 C. The residue is diluted with 150 g of methyl tert-butyl ether, cooled to 0C and filtered. The filter cake is washed twice with methyl tert-butyl ether. The pale grey solid is thereafter taken up in dilute hydrochloric acid and stirred.
The product is isolated by filtration and dried to constant weight.
Yield: 61.3 g _ 91.1 % of theory of white to pale yellow crystals with a melting point of 72-75C.
Z04~134;
Example 3: 1 -Phenylbutane- 1 ,3-dione ~C-CH2-8--CH3 The procedure of Example 1 is repeated, using in place of acetophenone 17.4 g of acetone and increasing the amount of solvent from 100 g to 150 g of dimethyl sulfoxide/tetra-hydrofuran.
Yield: 42.6 g _ 87.~ % of theory of a yellow crystalline powder with a melting point of 52-53C.
The NMR spectrum confirms that a mixture of 14 % of CH3--C - CH2- 8 o and 86 % of CH3--C = CH- C ~ is obtained.
OH
Example 4: 6-Methyl-l-phenylheptane-1,3-dione C - CH2- C ~ CH2~2CH~CH
Yhe procedure as described in Example 1 is repeated, replacing acetophenone with 34.5 g of 5-methyl-2-hexanone.
Working up after acidification of the reaction mixture with sulfuric acid is effected by extracting the aqueous solution with 2 x 100 ml of dichloromethane, then drying the extract over sodium sulfate, stripping off the solvent on a rotary evaporator and purifying the residue by distillation.
Yield: 52.8 g _ 80.6 % of theory of a yellow fluid with a boiling point of 2041i3~
98-100C/0.2 mbar and a refractive index nD : 1.5505.
Example 5: l-Phenyldodecane-l ,3-dione ~ C--CH2- C ~ CH2~8 CH3 The procedure as described in Example 1 is repeated, replacing acetophenone with 51.0 g of 2-undecanone.
Working up is as described in Example 4.
Yield: 74.6 g _ 90.7 % of theory of a colourless fluid with a boiling point of 140-42C/0.25 mbar and a melting point of 36-37C.
Example 6: 1 -Phenyl-6-n-dodecylthiohexane- 1 ,3-dione ~ C--CH2- C ~ CH2~3 S-n-C1 2H25 The procedure as described in Example 1 is repeated, but using 24 g of acetophenone and replacing methyl benzoate and sodium hydride with 66.6 g of methyl n-dodecylthio-butyrate and 21.2 g of sodium tert-butylate. Tetrahydrofuran is replaced by the same amount of toluene and the reaction temperature is 0C.
Yield after recrystallisation from isopropanol/water: 55.7 g _ 71.4 % of theory of white crystals with a melting point of 44C.
Example 7: 1-Phenyl-6-phenylthio-hexan-1 ,3-dion ~ C--CH2- C ~ CH2~3 S ~=3 Z04~3~
The procedure as described in Example 1 is repeated, using 18 g of acetophenone and 4.9 g of sodium hydride and replacing methyl benzoate with 34.7 g of methyl n-phenylthiobutyrate. Working up is effected as described in Example 4.
Yield: 33.4 g _ 74.4 % of theory of a yellow fluid with a boiling point of 178-82C/0.13 mbar and a refractive index nD0: 1.6185.
Example 8: 8-Hydroxy-l-phenyloctane-1,3-dione O O
~C - CH2- C ~ CH2t OH
A 0.5 1 Sovirel flask (double-walled reactor) fitted with stirrer, thermometer, separating funnel and distillation receiver is charged, under nitrogen, with 99.0 g of sodium methylate solution (30 % solution in methanol) and 117 g of dimethyl sulfoxide. Ca. 62 g of methanol are distilled from this solution, and the resultant suspension is cooled. Then 100 g of N-methylpyrrolidone are added at 30C and the batch is cooled to 0C. At this temperature, a solution of 60.0 g of acetophenone, 62.8 g of ~-caprolactone and 17.0 g of N-methylpyrrolidone are added over 1 hour. The mixture is stirred for 30 minutes at 0C
and for 2 hours at 20C. At a sump temperature of <70C, ca. 120 g of solvent are distilled from the product solution. After cooling to 30C, 300 ml of water are added to the residue.
The solution is extracted with 3 x 70 ml of xylene, the aqueous phase is diluted with water to 1200 ml, and the pH is then adjusted to 5.5 with ca. 28 ml of 50 % sulfuric acid. The precipitated product is isolated by filtration, washed on the filter with 100 ml of water and dAed to constant weight under vacuum at ca. 30C.
Yield: 85.0 g ; 72.6 % of theory of slightly yellowish crystals with a melting point of 46-48C.
Purity according to gas chromatography: 97.3 %.
Example 9: 6-Hydroxy- 1 -phenylhexane- 1,3-dione o O
C-CH2-CtCH2t30H
60.0 g of acetophenone, 47.4 g of butyrolactone and 99.0 g of sodium methylate (30 %
solution in methanol) are reacted in the same manner as described in Example 8. After working up as described in Example 8, the product precipitates from the mother solution after several hours. The precipitate is isolated by f Itration, washed with water and dried to constant weight under vacuum at ca. 30C.
Yield: 70.0 g _ 68 % of theory of yellow crystals with a melting point of 35C.
Example 10: 8-Hydroxy- 1 -phenyloctane- 1,3-dione O O
ll ll ,~C - CH2- C ~ CH2t OH
An apparatus as described in Example 8 is charged with 30.8 g of sodium methylate (97 %), 117.0 g of DMSO and 117.0 g of dioxane and the mixture is cooled to 0C. At this temperature, a solution of 61.3 g of acetophenone, 57.7 g of ~-caprolactone and 17.0 g of dioxane are added, with stirring, over I hour. Stirring is continued for 30 minutes at 0C
and then for 2 hours at 20C. Subsequently ca. 220 g of solvent are distilled from the reaction mixture at 70C and under reduced pressure.
3()0 g of water are added to the residue and the suspension is extracted with 3 x 70 ml of xylene. The aqueous phase is diluted to 1000 ml and adjusted to pH ~ S with sulfuric acid.
The precipitated product is isolated by filtration and dried.
Yield: 78.1 g _ 66.6 % of theory of yellowish cr~stals with a melting point of 47-50C.
204~13 Replacing the sodium methylate with 52.9 g of sodium tert-butylate gives a yield of 79.0 g _ 67.4 % of theory.
Example 11: 8-Hydroxy-1-phenyloctane-1,3-dione O O
C - CH2- C ~ CH2t5H
In accordance with the procedure of Example 8, 61.3 g of acetophenone and 57.7 g of ~-caprolactone are condensed in 117.0 g of N-methylpyrrolidone as solvent with 52.9 g of sodium tert-butylate (97 %) as base. Working up is as described in Example 8.
Yield: 73.0 g _ 62.3 % of theory of yellowish crystals with a melting point of 47-50C.
Example 12: 1,3-Diphenyl-propan-1,3-dion O O
0~C - CH2- C ~3 An apparatus as described in Example 1 is charged with 18.0 g of sodium methylate (97 %), 100 g of DMSO, 100 g of dioxane and 6 g of methanol and the mixture is cooled to 0C. Then a mixture of 45 g of methyl benzoate and 36 g of acetophenone are added dropwise over 35 minutes. The reaction mixture is then stirred for ca. 45-60 minutes at 30C.
Workin~ up method A:
The solvent is distilled off on the rotary evaporator (bath temperature <60C) and the residue is dissolved in ~()() ml of water. The aqueous solution is acidi~led with dilute hydrochloric acid and the precipitate is isolated by filtration, washed with water and dried.
Yield: 60.0 g _ 89.2 % of theory.
Purity: >98 % determined by 13C-NMR spectroscopy.
20~13~
Melting point: 72-75C.
Workin~ up method B:
The solvent is removed by distillation in the Sovirel reactor (bath temperature <60C) so long as the residue can be stirred. The oily residue is then taken up in 200 ml of methyl tert-butyl ether (MTBE), and the ethereal solution is cooled to 0C and filtered. The filter residue is washed with 2 x 100 ml of MTBE and with 2 x 50 ml of petroleum ether (50-70C). The pale grey solid is taken up in 500 ml of water, the aqueous solution is acidified with dilute hydrochloric acid, and the precipitate is isolated by filtration and dried.
Yield: 58.1 g _ 86.3 % of theory.
Purity: >98 % determined by l3C-NMR spectroscopy.
Melting point: 72-75C.
_xample 13:
O O
~ C--CH2- C ~
99 g of methyl stearate and 36 g of acetophenone are condensed in accordance with the procedure described in Example 12.
Workin~ uP method A:
The solvent is removed by distillation on the rotary evaporator (bath temperature <60C) and the residue is taken up in 1000 ml of water. The aqueous solution is acidified with dilute hydrochloric acid and the precipitate is isolated by filtration, washed with 3~0 ml of methanol and dried (109.1 g = 94 % of theory). The crude product is crystallised by fractional crystallisation from 600 ml of boiling methanol.
Yield: 78.8 g _ 68 % of theory.
Purity: >98 % deterrnined by 13C-NMR spectroscopy.
Melting point: 60-64C.
204~3.~
Workin~ up method B:
The solvent is removed by distillation in the Sovirel reactor (bath temperature <60C) so long as the residue can be stirred. The oily residue is then talcen up in 200 ml of methanol and the methanolic solution is cooled to 20C and filtered. The filter residue is washed with 2 x 100 ml of methanol. The pale grey solid (sodium salt of the diketone) is taken up in 750 ml of water and the aqueous solution is acidified with dilute hydrochloric acid, and the precipitate is isolated by filtration and dried.
Yield: 87.6 g _ 75.5 % of theory.
Melting point: 60-64C.
Example 14: 1-Phenyloctadecane-1 3-dione O O
0~ :
An apparatus as described in Example 1 is charged with 31.7 g of sodium-tert-butylate, 150 g of DMSO and 150 g of tetrahydrofuran (THF) and the mixture is cooled to 0C.
Then a mixture of 89 g of methyl palmitate and 36 g of acetophenone is added dropwise over 45 minutes. The reaction mixture is then stirred for ca. 45-60 minutes at 30C, the solvent is removed by distillation on a rotary evaporator (bath temperature <60C), and the residue is taken up in 1000 ml of water. The aqueous solution is acidified with dilute hydrochloric acid and the precipitate is isolated by filtration, washed with water, and dried.
The crude product (110.6 g) is crystallised once by fractional crystallisation from 400 ml of methanol.
~field: 68.9 g _ 64.0 % of theory.
Purity: >98 % determined by l3C-NMR spectroscopy.
Melting point: 62-6~C.
2~141~13 Example 15: 1,4-Diphenylbutane-1,3-dione ~ CH2-C-CH2-Q ~ 3 The procedure as described in Example 1 is repeated, using in place of sodium hydride 31.7 g of sodium tert-butylate and, in place of methyl benzoate, 54.2 g of ethylphenylacetate.
Yield: 60.7 g _ 84.9 % of theory of a yellow waxlike substance, which is recrystallised from 200 ml of isopropanol/30 ml of water. Melting point 47-48C.
Example 16: Temperature profile of the process All reactions are carried out for dibenzoylmethane (product of Example 1) in dirnethyl sulfoxide/dioxane with sodium methylate as base + 3 % methanol. The process described in Example 1 is carried out. The reaction temperature is varied from 0 to 70C.
The results are reported in Table 1.
Table 1 Reaction temperature in C Yleld in % Purity in %
0 89.2 99 91.4 97 90.3 98 90.3 94 80.8 99 82.4 96 The experiments show that an increase in temperature above 50C results in no further increase in yield.
The precipitated product is isolated by filtration and dried.
Yield: 78.1 g _ 66.6 % of theory of yellowish cr~stals with a melting point of 47-50C.
204~13 Replacing the sodium methylate with 52.9 g of sodium tert-butylate gives a yield of 79.0 g _ 67.4 % of theory.
Example 11: 8-Hydroxy-1-phenyloctane-1,3-dione O O
C - CH2- C ~ CH2t5H
In accordance with the procedure of Example 8, 61.3 g of acetophenone and 57.7 g of ~-caprolactone are condensed in 117.0 g of N-methylpyrrolidone as solvent with 52.9 g of sodium tert-butylate (97 %) as base. Working up is as described in Example 8.
Yield: 73.0 g _ 62.3 % of theory of yellowish crystals with a melting point of 47-50C.
Example 12: 1,3-Diphenyl-propan-1,3-dion O O
0~C - CH2- C ~3 An apparatus as described in Example 1 is charged with 18.0 g of sodium methylate (97 %), 100 g of DMSO, 100 g of dioxane and 6 g of methanol and the mixture is cooled to 0C. Then a mixture of 45 g of methyl benzoate and 36 g of acetophenone are added dropwise over 35 minutes. The reaction mixture is then stirred for ca. 45-60 minutes at 30C.
Workin~ up method A:
The solvent is distilled off on the rotary evaporator (bath temperature <60C) and the residue is dissolved in ~()() ml of water. The aqueous solution is acidi~led with dilute hydrochloric acid and the precipitate is isolated by filtration, washed with water and dried.
Yield: 60.0 g _ 89.2 % of theory.
Purity: >98 % determined by 13C-NMR spectroscopy.
20~13~
Melting point: 72-75C.
Workin~ up method B:
The solvent is removed by distillation in the Sovirel reactor (bath temperature <60C) so long as the residue can be stirred. The oily residue is then taken up in 200 ml of methyl tert-butyl ether (MTBE), and the ethereal solution is cooled to 0C and filtered. The filter residue is washed with 2 x 100 ml of MTBE and with 2 x 50 ml of petroleum ether (50-70C). The pale grey solid is taken up in 500 ml of water, the aqueous solution is acidified with dilute hydrochloric acid, and the precipitate is isolated by filtration and dried.
Yield: 58.1 g _ 86.3 % of theory.
Purity: >98 % determined by l3C-NMR spectroscopy.
Melting point: 72-75C.
_xample 13:
O O
~ C--CH2- C ~
99 g of methyl stearate and 36 g of acetophenone are condensed in accordance with the procedure described in Example 12.
Workin~ uP method A:
The solvent is removed by distillation on the rotary evaporator (bath temperature <60C) and the residue is taken up in 1000 ml of water. The aqueous solution is acidified with dilute hydrochloric acid and the precipitate is isolated by filtration, washed with 3~0 ml of methanol and dried (109.1 g = 94 % of theory). The crude product is crystallised by fractional crystallisation from 600 ml of boiling methanol.
Yield: 78.8 g _ 68 % of theory.
Purity: >98 % deterrnined by 13C-NMR spectroscopy.
Melting point: 60-64C.
204~3.~
Workin~ up method B:
The solvent is removed by distillation in the Sovirel reactor (bath temperature <60C) so long as the residue can be stirred. The oily residue is then talcen up in 200 ml of methanol and the methanolic solution is cooled to 20C and filtered. The filter residue is washed with 2 x 100 ml of methanol. The pale grey solid (sodium salt of the diketone) is taken up in 750 ml of water and the aqueous solution is acidified with dilute hydrochloric acid, and the precipitate is isolated by filtration and dried.
Yield: 87.6 g _ 75.5 % of theory.
Melting point: 60-64C.
Example 14: 1-Phenyloctadecane-1 3-dione O O
0~ :
An apparatus as described in Example 1 is charged with 31.7 g of sodium-tert-butylate, 150 g of DMSO and 150 g of tetrahydrofuran (THF) and the mixture is cooled to 0C.
Then a mixture of 89 g of methyl palmitate and 36 g of acetophenone is added dropwise over 45 minutes. The reaction mixture is then stirred for ca. 45-60 minutes at 30C, the solvent is removed by distillation on a rotary evaporator (bath temperature <60C), and the residue is taken up in 1000 ml of water. The aqueous solution is acidified with dilute hydrochloric acid and the precipitate is isolated by filtration, washed with water, and dried.
The crude product (110.6 g) is crystallised once by fractional crystallisation from 400 ml of methanol.
~field: 68.9 g _ 64.0 % of theory.
Purity: >98 % determined by l3C-NMR spectroscopy.
Melting point: 62-6~C.
2~141~13 Example 15: 1,4-Diphenylbutane-1,3-dione ~ CH2-C-CH2-Q ~ 3 The procedure as described in Example 1 is repeated, using in place of sodium hydride 31.7 g of sodium tert-butylate and, in place of methyl benzoate, 54.2 g of ethylphenylacetate.
Yield: 60.7 g _ 84.9 % of theory of a yellow waxlike substance, which is recrystallised from 200 ml of isopropanol/30 ml of water. Melting point 47-48C.
Example 16: Temperature profile of the process All reactions are carried out for dibenzoylmethane (product of Example 1) in dirnethyl sulfoxide/dioxane with sodium methylate as base + 3 % methanol. The process described in Example 1 is carried out. The reaction temperature is varied from 0 to 70C.
The results are reported in Table 1.
Table 1 Reaction temperature in C Yleld in % Purity in %
0 89.2 99 91.4 97 90.3 98 90.3 94 80.8 99 82.4 96 The experiments show that an increase in temperature above 50C results in no further increase in yield.
Claims (12)
1. A process for the preparation of a linear 1,3-diketone of general formula I
(I) wherein R1 and R2 are each independently of the other C1-C20alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, NO2, C1-C4alkyl and/or C1-C4alkoxy, or are C7-C9phenylalkyl or a radical of formula II
-A-X-R4 (II) wherein A is C1-C12alkylene, phenylene or phenylene which is substituted by halogen, hydroxy, NO2, C1-C4alkyl and/or C1-C4alkoxy, or is C1-C12alkylene which is substituted byhydroxy, halogen and/or alkoxy, X is oxygen or sulfur, and R4 is hydrogen, C1-C18alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, C1-C4alkyl, NO2 and/or C1-C4alkoxy, or is C7-C9phenylalkyl, and R3 is hydrogen, C1-C20alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, C1-C4alkyl, NO2 and/or C1-C4alkoxy, or is C7-C9phenylalkyl, by a Claisen condensation of a ketone of formula III
(III) with an ester of formula IV
(IV) wherein R5 is C1-C5alkyl, phenyl or phenyl which is substituted by halogen, C1-C4alkyl or hydroxy;
or, if R2 in formula I is -(CH2)mOH, also with a cyclic ester of formula V
(V) in which m is 2 to 10, in the presence of a hydride of an alkali metal or alkaline earth metal or of a C1-C5alcoholate of an alkali metal or alkaline earth metal as base, which process comprises carrying out the reaction in a mixture of dimethyl sulfoxide and at least one organic solvent which is inert under the reaction conditions.
(I) wherein R1 and R2 are each independently of the other C1-C20alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, NO2, C1-C4alkyl and/or C1-C4alkoxy, or are C7-C9phenylalkyl or a radical of formula II
-A-X-R4 (II) wherein A is C1-C12alkylene, phenylene or phenylene which is substituted by halogen, hydroxy, NO2, C1-C4alkyl and/or C1-C4alkoxy, or is C1-C12alkylene which is substituted byhydroxy, halogen and/or alkoxy, X is oxygen or sulfur, and R4 is hydrogen, C1-C18alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, C1-C4alkyl, NO2 and/or C1-C4alkoxy, or is C7-C9phenylalkyl, and R3 is hydrogen, C1-C20alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, C1-C4alkyl, NO2 and/or C1-C4alkoxy, or is C7-C9phenylalkyl, by a Claisen condensation of a ketone of formula III
(III) with an ester of formula IV
(IV) wherein R5 is C1-C5alkyl, phenyl or phenyl which is substituted by halogen, C1-C4alkyl or hydroxy;
or, if R2 in formula I is -(CH2)mOH, also with a cyclic ester of formula V
(V) in which m is 2 to 10, in the presence of a hydride of an alkali metal or alkaline earth metal or of a C1-C5alcoholate of an alkali metal or alkaline earth metal as base, which process comprises carrying out the reaction in a mixture of dimethyl sulfoxide and at least one organic solvent which is inert under the reaction conditions.
2. A process according to claim 1 for the preparation of a compound of formula I, wherein R1 and R2 are each independently of the other C1-C20alkyl, phenyl, (C1-C4alkyl)phenyl or a radical of formula II, A is C1-C6alkylene, R4 is hydrogen, C1-C18alkyl, phenyl or (C1-C4alkyl)phenyl, and R3 is hydrogen and C1-C4alkyl.
3. A process according to claim 2 for the preparation of a compound of formula I, wherein R1 and R2 are each independently of the other C1-C18alkyl, phenyl or a radical of formula II, R4 is hydrogen, phenyl or C1-C18alkyl, and R3 is hydrogen.
4. A process according to claim 1, wherein the amount of dimethyl sulfoxide in the mixture with at least one organic solvent which is inert under the reaction conditions is 10 to 80%.
5. A process according to claim 1, wherein the inert solvent is selected from the group consisting of linear or cyclic ethers, aliphatic or aromatic hydrocarbons and cyclic or linear amides.
6. A process according to claim 5, wherein the inert solvent is selected from the group consisting of dioxane, tetrahydrofuran, diethylene glycol dimethyl ether, methyl tert-butyl ether, toluene and N-methylpyrrolidone.
7. A process according to claim 1, wherein the Claisen condensation reaction is carried out in the temperature range from -20 to +70°C.
8. A process according to claim 7, wherein the reaction is carried out in the temperature range from -5 to +40°C.
9. A process according to claim 1, wherein the reaction time of the Claisen condensation is from 0.5 to 5 hours.
10. A process according to claim 1, wherein the alkali metal salt or alkaline earth metal salt of the diketone is precipitated direct from the reaction solution and isolated, and the diketone is obtained pure by hydrolysis with dilute acid.
11. A process according to claim 1, wherein the base is a sodium alcoholate.
12. A process according to claim 1, wherein the base is NaOCH3, NaO-t-C4H9 or NaH.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH1424/90-9 | 1990-04-26 | ||
| CH142490 | 1990-04-26 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2041134A1 true CA2041134A1 (en) | 1991-10-27 |
Family
ID=4210138
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002041134A Abandoned CA2041134A1 (en) | 1990-04-26 | 1991-04-24 | Process for the preparation of linear 1,3-diketones |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0454623B1 (en) |
| JP (1) | JPH04225935A (en) |
| KR (1) | KR0168056B1 (en) |
| CA (1) | CA2041134A1 (en) |
| DE (1) | DE59106456D1 (en) |
| ES (1) | ES2077208T3 (en) |
| TW (1) | TW223625B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5892053A (en) * | 1995-05-25 | 1999-04-06 | G. D. Searle & Co. | Process for preparing 3-haloalkyl-1H-pyrazoles |
| US8137500B2 (en) | 2005-01-22 | 2012-03-20 | Henkel Kgaa | Sprayable low-viscosity rubber damping compounds |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4744815B2 (en) * | 2003-06-10 | 2011-08-10 | 昭和電工株式会社 | β-diketone compound, metal complex thereof, and method for producing metal compound |
| TW200504083A (en) * | 2003-06-10 | 2005-02-01 | Showa Denko Kk | Processes for preparing β-diketone compound, metal complex thereof and metallic compound |
| GB0719180D0 (en) * | 2007-10-02 | 2007-11-14 | Cambrex Karlskoga Ab | New process |
| CN102171200B (en) * | 2008-10-02 | 2015-09-30 | 坎布雷卡尔斯库加公司 | For the preparation of the method for diones and medicine |
| FR2964964B1 (en) * | 2010-09-20 | 2013-10-18 | Dexera | PROCESS FOR THE SYNTHESIS OF BETA-DICARBONYL COMPOUNDS |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3004932A (en) * | 1958-01-15 | 1961-10-17 | Dow Chemical Co | Unsaturated beta-diketones and polymers and co-polymers thereof |
| DE1618444A1 (en) * | 1967-06-24 | 1971-04-01 | Hoechst Ag | Process for the production of ss-diketones |
| DE1618442A1 (en) * | 1967-06-24 | 1970-12-17 | Hoechst Ag | Process for the preparation of cyclic ss-diketones |
| US4482745A (en) * | 1983-11-02 | 1984-11-13 | American Cyanamid Company | Procedure for preparing 1,3-diphenyl-1,3-propanedione |
-
1991
- 1991-04-12 KR KR1019910006004A patent/KR0168056B1/en not_active IP Right Cessation
- 1991-04-17 DE DE59106456T patent/DE59106456D1/en not_active Expired - Fee Related
- 1991-04-17 EP EP91810289A patent/EP0454623B1/en not_active Expired - Lifetime
- 1991-04-17 ES ES91810289T patent/ES2077208T3/en not_active Expired - Lifetime
- 1991-04-24 CA CA002041134A patent/CA2041134A1/en not_active Abandoned
- 1991-04-24 TW TW080103210A patent/TW223625B/zh active
- 1991-04-26 JP JP3125587A patent/JPH04225935A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5892053A (en) * | 1995-05-25 | 1999-04-06 | G. D. Searle & Co. | Process for preparing 3-haloalkyl-1H-pyrazoles |
| US5910597A (en) * | 1995-05-25 | 1999-06-08 | G.D. Searle & Co. | Process for preparing 3-haloalkyl-1H-pyrazoles |
| US8137500B2 (en) | 2005-01-22 | 2012-03-20 | Henkel Kgaa | Sprayable low-viscosity rubber damping compounds |
Also Published As
| Publication number | Publication date |
|---|---|
| TW223625B (en) | 1994-05-11 |
| DE59106456D1 (en) | 1995-10-19 |
| JPH04225935A (en) | 1992-08-14 |
| KR910018334A (en) | 1991-11-30 |
| EP0454623A1 (en) | 1991-10-30 |
| ES2077208T3 (en) | 1995-11-16 |
| EP0454623B1 (en) | 1995-09-13 |
| KR0168056B1 (en) | 1999-03-20 |
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