Classifications

• • 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
• • 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
  • C07C45/673—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 change of size of the carbon skeleton
  • C07C45/676—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 change of size of the carbon skeleton by elimination of carboxyl groups

Definitions

• the invention relates to an improved process for the production of ⁇ , ⁇ -unsaturated ketones, in particular methylheptenone, geranyl acetone and farnesylacetone or their dihydro derivatives or geranylgeranylacetone by a Carroll reaction in the presence of aluminum catalysts.
• a Carroll reaction is the chain extension of an allyl or propargyl alcohol with acetoacetate or diketene to form ⁇ , ⁇ -unsaturated ketones. For example, it can proceed according to the following reaction scheme:
• the new acetoacetic ester of the unsaturated alcohol which is primarily formed from the allyl or propargyl alcohol and the acetoacetic acid ester or diketene, is rearranged in a Claisen rearrangement to give ⁇ -keto acid, which then spontaneously decarboxylates.
• the terpenes required as essential precursors for vitamin A and vitamin E are 2-methyl-2-hepten-6-one, 6, 10-dimethyl-5, 9-undecadien-2-one (geranylacetone) and 6, 10 , 14-Trimethyl-5, 9, 13-pentadecatrien-2-one (farnesylacetone), produced on an industrial scale by the Carroll reaction.
• aluminum alcoholates in particular the aluminum isopropylate of the formula AI (0-CH (CH 3 ) 2 ) 3 , were used as catalysts for Carroll reactions in amounts of 0.8 to 2.5 mol% on the alcohol used as the starting material.
• aluminum complexes with acetylacetone or acetoacetic esters such as aluminum tri (acetylacetonate), aluminum tri (methyl acetoacetate) or aluminum tri (ethyl acetoacetate), were used as catalysts for Carroll reactions.
• the invention relates to a process for the preparation of ⁇ , ⁇ -unsaturated ketones of the general formula I
• R 1 represents H or a saturated or unsaturated branched hydrocarbon radical with 1 to 33 C atoms, optionally substituted by methoxy groups, and the dotted line can represent a further bond between the C atoms carrying it,
• an acetoacetic acid alkyl ester at temperatures of 150 to 45 220 ° C in an optionally modified Carroll reaction in the presence of an aluminum catalyst and distilling off the alkanol which is formed, which is characterized in that an acetoacetic acid ester of the general formula III as the acetoacetic acid alkyl ester
• R 2 represents an alkyl group having 1 to 4 carbon atoms.
• the higher ⁇ , ⁇ -unsaturated ketones can be obtained in yields of 92 to 96% of theory in a simple manner and in continuous process control, which is particularly desirable for processes on an industrial scale, even if none Excess or only a slight excess of one of the reaction components is used. Furthermore, it is a great advantage that the space-time yields of the previously known methods can be increased by the method according to the invention.
• n stands for an integer from 1 to 5 and x and y either stand for H, or x stands for methoxy and y stands for H or x and y together for an additional bond between the C and X bearing y Atoms are, such as 3, 7-dimethyl-1,6-octadien-3-ol (linalool),
• acetoacetic acid tert. -butyl ester or ter. - Amyl ester has the advantage of faster conversion and the avoidance of by-products.
• the quantities used Reactants are advantageously chosen so that a molar ratio of alcohol of formula II to acetoacetic acid alkyl ester of formula III is between 0.8 and 1.2, preferably from 0.95 to 1.10.
• Suitable organic aluminum compounds for the process according to the invention are essentially compounds of the general formula V.
• R 4 is branched or unbranched alkyl or alkoxy groups with 1 to 4 C atoms, preferably methyl or ethyl groups
• R 5 and R 5 is branched or unbranched alkyl or alkoxy groups with 1 to 5 C atoms, preferably one Are methyl or a 2-butyl group
• R 7 is a branched or unbranched alkyl group having 1 to 4 carbon atoms and m and n can be an integer from 0 to 3, where n + m 3 3, and Aluminum triaryloxylates into consideration.
• Liquid aluminum compounds, in particular aluminum compounds, in which R 5 is a methyl radical, R 6 is a butyl radical and the sum of n + m ⁇ 3 and the ratio n / m> 0.3 are particularly preferred.
• the first-mentioned catalysts are therefore lower aluminum trialcoholates, such as aluminum trimethylate, triethylate, triisopropoxide, tri-sec. -butylate and compounds which are formed in the reaction of the aluminum trialcoholates mentioned with stoichiometric amounts of acetylacetonate, alkyl acetoacetate or alkyl malonate with elimination of alcohol and transesterification.
• aluminum trialcoholates such as aluminum trimethylate, triethylate, triisopropoxide, tri-sec. -butylate and compounds which are formed in the reaction of the aluminum trialcoholates mentioned with stoichiometric amounts of acetylacetonate, alkyl acetoacetate or alkyl malonate with elimination of alcohol and transesterification.
• Examples include aluminum triacetoacetate, aluminum triacetylacetonate, aluminum monoacetoacetate diethylate, aluminum monoacetoacetate diisopropylate, aluminum diacetoacetate
• the aluminum trialcoholates are preferably used.
• -butylate Mixed aluminum triacetoacetates, which are obtained by reacting aluminum sec. -butylate or aluminum triisopropylate with methyl acetoacetate with elimination of 2-butanol or iso-propanol and transesterification of the methoxy groups with the released 2-butanol or iso-propanol, the degree of transesterification should be over 30%.
• aluminum triaryloxylates the aluminum salts of aromatic hydroxy compounds such as aluminum triphenolate, aluminum tricresolates, aluminum trixylene enolates, aluminum tri- naphtholates, the aryl radicals of which can also be substituted by lower alkyl or alkyloxy groups, ie alkyl or alkyloxy groups having 1 to 4 carbon atoms, hydroxyl groups or phenyl.
• the relatively easily accessible aluminum triphenolate is used with particular advantage.
• liquid catalysts or solutions of solid catalysts It is advantageous to use liquid catalysts or solutions of solid catalysts and to feed them into the reaction vessel in liquid form.
• liquid catalysts or solutions of solid catalysts For example, aluminum trialcoholates dissolved in alkyl acetoacetate or a mixture of alkyl acetoacetate and an alcohol of the general formula II can be used.
• the amount of the aluminum compound is generally such that its concentration in the reaction mixture does not fall below 0.05% by weight Al and does not exceed 6% by weight Al at the start of the reaction. Based on the alkyl acetoacetate to be reacted, 0.5 to 5 mol% of the aluminum compound are generally required.
• radicals R 1 , R 2 and R 3 are H, methyl or ethyl, preferably H or methyl and R 4 is H, methyl, ethyl, isopropyl, phenyl or methoxymethyl, preferably H or methyl , as a solvent.
• Cyclic 5-ring carbonates of the general formula VI are, in addition to the customary alkylene carbonates, such as ethylene carbonate, 1, 2-propylene carbonate, isobutylene carbonate and 1, 2-butylene carbonate, ie carbonates of the general formula VI, in which R 1 to R 4 are H or methyl, or R 1 to R 3 is H or methyl and R 4 is ethyl, also those in which R 1 to R 3 can additionally be ethyl and R 4 is H, methyl, ethyl, Isopropyl, phenyl or methoxymethyl. 5
• the cyclic carbonates used can also be produced very inexpensively on an industrial scale by reacting the corresponding alkylene oxides with CO 2 . They generally have such high boiling points that temperatures of 10 170 ° C can be easily reached under normal pressure.
• Particularly suitable 5-ring lactones of the general formula VII are v-butyrolactone and 3-methyl- ⁇ -butyrolactone, in particular ⁇ -butyrolactone. 15
• ⁇ -butyrolactones of the general formula VII used according to the invention can also be prepared on an industrial scale by dehydrogenation of the corresponding butanediols.
• the alkanol formed in the reaction surprisingly attacks the cyclic carbonates or lactones under the reaction conditions so little that, for example, when using propylene carbonate, the solvent can be reused for up to 10 reaction cycles without any purification
• the 5-ring carbonates and 5-ring lactones are generally used in amounts of 50 to 1000% by weight, preferably 100 to 500% by weight, based on the ⁇ , ⁇ -unsaturated ketone formed.
• the Carroll reaction can advantageously also be carried out without the addition of substantial amounts of a solvent. This has advantages when working up the reaction mixture.
• the process according to the invention can be carried out batchwise and continuously.
• the procedure is advantageously such that the starting compounds and the catalyst are combined with a
• reaction vessel with attached condensation device for the alcohol released and for the discharge of Pumped carbon dioxide and pumps the reaction product with the help of an overflow.
• the wished ⁇ , ⁇ -unsaturated ketones of the general formula I can be obtained in a simple manner with surprisingly high yields.
• the tertiary alcohols released from the acetoacetic acid ester can be recovered almost completely.
• a mixture of a mixture of 50 ml (45 g) 1, 2-propylene carbonate and 2.8 g of a separately (according to GB 886 353) aluminum tri-methylacetoacetate catalyst was made at 170 ° C within 2 hours 25.7 g of a 92% 2-methyl-3-butene-2-ol and 39.8 g of acetoacetic acid tert. -butyl ester added dropwise.
• the mixture was stirred for a further 10 minutes (min) until the evolution of gas had ended and then cooled.
• reaction discharge was distilled under a pressure reduced to 0.1 mbar.
• a total of 139.7 g of 6, 10-dimethyl-5, 9-undecadien-2-one (geranylacetone) was obtained in two fractions, which corresponds to a yield of 96% of theory.
• Example 2a 5.6 g of the aluminum catalyst described there were introduced as in Example 2a) and a mixture of 115.4 g of linalool and 94 g of methyl acetoacetate was pumped in at an internal temperature of 180 ° C. This spontaneously formed C0 2 and methanol, which was condensed. As in Example 2a), the reaction mixture was stirred for a further 20 min until the CO 2 evolution had ceased and then cooled. It was distilled under reduced pressure and 133 g of geranyl acetone were obtained. The yield was 91.5% of theory. As a side pro Products had formed 1.6 g of 6, 10-dimethyl-5, 9-undecadien-2-ol, which were not detectable in Example 2a).
• E E-geranyllinalool. This solution was pumped evenly into the horizontal reactor vessel described in Example 3a). The pumping rate was matched to the available reaction volume so that there was an average residence time of 10 ⁇ 0.5 min. At 190-200 ° C 35 internal temperature, the mixture reacted continuously to geranylgeranylacetone. After the feed had ended, the contents of the reactor were heated for a further 10 minutes and then added to the cooled reaction discharge. It was distilled at 0.3 mbar and 84.2 g of geranylgeranylacetone with a purity of 40 97.1% were obtained in the main fraction. This corresponds to a yield of 85% of theory.
• Example 6a A comparison of Example 6a with Comparative Example 6b clearly shows that the reaction with the acetoacetic acid tert. - Butyl ester runs much faster (3 to 10 times faster) than that with the methyl acetoacetate previously used for Carroll reactions.

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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)

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Citations (4)

• 1998
  • 1998-09-07 DE DE19840746A patent/DE19840746A1/de not_active Withdrawn
• 1999
  • 1999-09-02 CA CA002343521A patent/CA2343521A1/en not_active Abandoned
  • 1999-09-02 EP EP99946093A patent/EP1112245A1/de not_active Withdrawn
  • 1999-09-02 WO PCT/EP1999/006447 patent/WO2000014046A1/de not_active Application Discontinuation
  • 1999-09-02 ID IDW20010546A patent/ID27392A/id unknown
  • 1999-09-02 CN CN99812906A patent/CN1348434A/zh active Pending
  • 1999-09-02 IL IL14168999A patent/IL141689A0/xx unknown
  • 1999-09-02 JP JP2000568806A patent/JP2002524435A/ja not_active Withdrawn
  • 1999-09-02 KR KR1020017002894A patent/KR20010074970A/ko not_active Application Discontinuation
  • 1999-09-02 AU AU58583/99A patent/AU5858399A/en not_active Abandoned

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