US3658925A - Metalation of limonene and syntheses of limonene derivatives - Google Patents

Metalation of limonene and syntheses of limonene derivatives Download PDF

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US3658925A
US3658925A US888893A US3658925DA US3658925A US 3658925 A US3658925 A US 3658925A US 888893 A US888893 A US 888893A US 3658925D A US3658925D A US 3658925DA US 3658925 A US3658925 A US 3658925A
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limonene
metalated
solution
metalation
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William F Erman
Charles D Broaddus
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Procter and Gamble Co
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    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
    • C11B9/00—Essential oils; Perfumes
    • C11B9/0026—Essential oils; Perfumes compounds containing an alicyclic ring not condensed with another ring
    • C11B9/0034—Essential oils; Perfumes compounds containing an alicyclic ring not condensed with another ring the ring containing six carbon atoms
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C403/00—Derivatives of cyclohexane or of a cyclohexene or of cyclohexadiene, having a side-chain containing an acyclic unsaturated part of at least four carbon atoms, this part being directly attached to the cyclohexane or cyclohexene or cyclohexadiene rings, e.g. vitamin A, beta-carotene, beta-ionone
    • C07C403/02—Derivatives of cyclohexane or of a cyclohexene or of cyclohexadiene, having a side-chain containing an acyclic unsaturated part of at least four carbon atoms, this part being directly attached to the cyclohexane or cyclohexene or cyclohexadiene rings, e.g. vitamin A, beta-carotene, beta-ionone having side-chains containing only carbon and hydrogen atoms
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F1/00—Compounds containing elements of Groups 1 or 11 of the Periodic Table
    • C07F1/02—Lithium compounds
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S585/00—Chemistry of hydrocarbon compounds
    • Y10S585/929—Special chemical considerations
    • Y10S585/947—Terpene manufacture or recovery

Definitions

  • This invention relates to a novel compound, 2-(4-methylcyclohex-3-en-1-yl)allyllithium, and a process for its preparation.
  • the novel compound, 2- (4-methylcyclohex-3-en-l-yl)allyllithium will be referred to as metalated limonene.
  • the invention concerns processes of conversion of the metalated limonene to fl-bisabolene, p-mentha 1,8() diene-9-ol, lanceol, lanceal, 9 carboXy-p-mentha-1,8(10)-diene and 9-carbomethoxy-p-mentha1,8( 10)-diene.
  • One of the more important classes of perfume materials has come from the class of materials known as the essential oils.
  • These naturally occurring oils are extracts or distillates of the flowers, fruits, leaves, or roots of many different plants.
  • Each essential oil though, has an order or flavor that is characteristic of the plant from which it is isolated.
  • the oils usually contain a large number of individual components, the relative proportions and nature of which differ depending on the plant source. Rather exhaustive studies in recent years have been conducted to determine the constituents found in the essential oils and, as might be expected, the studies have shown that not all of the constituents of a particular oil contribute to its aroma. Thus any attempt to duplicate the aroma of a naturally occurring essential oil does not necessarily require a synthesis of each individual constituent.
  • the invention disclosed herein also describes a novel process for the production of p-mentha-1,8(10)-dien-9-ol, a citrus oil constituent.
  • the synthesis of this compound :as described hereinafter is simplified by conversion of the metalated limonene to the alcohol.
  • lanceol, lanceal, and p-mentha-I, 8( 10)-dien-9-ol are useful in and of themselves as perfume materials, they are also useful in the reconstitution of natural essential oils.
  • reconstitution is meant the mixing together of all the various individual synthesized components in the same percentages as found in the naturally occurring oil.
  • perfume materials such as 9-carboxy-p-menthal.8(10)-diene and 9 carbomethoXy-p-mentha-1,8-(10)- diene can also be synthesized from the novel intermediate found in the instant invention, i.e., metalated limonene.
  • the materials are known to possess a musty, earthy, minty, floral odor.
  • this invention concerns the discovery of metalation of a known and readily available compound, limonene, to form a stable intermediate and the further discovery that this intermediate can be converted to a wide variety of known and useful compounds.
  • one of the objects of the present invention is to make an intermediate useful for the synthesis of known and useful perfume and flavor compounds More specifically, an object of the invention is to produce metalated limonene.
  • Another object of the invention is to provide a novel process for the conversion of limonene to metalated limonene
  • Another object of the invention is to synthesize a variety of materials from metalated limonene.
  • Another object is to convert metalated limonene to Ianceal.
  • Another object is to provide a novel process for the production of p-mentha-l,8(10)-dien-9-ol.
  • Another object of the invention' is to provide a process for the production of ,B-bisabolene from metalated limonene.
  • a further object is to produce 9-carboxy-p-menth'a-l, 8(10)-diene.
  • Still a further object is to provide a process for the production of 9-carboxy-p-mentha-L8(10)-diene from metalated limonene.
  • Another object is to produce 9-carbomethoxy-p-mentha-1,8( 10) -diene,
  • limonene is first metalated to form a stable intermediate suitable for the synthesis of many known and useful compounds.
  • metalation and used herein is meant a reaction involving metal-hydrogen exchange.
  • the starting material limonene is a readily available naturally occurring substance. It is one of the most widely distributed terpenes in nature and is found in several essential oils, in some as the main constituent, especially in citrus oils.
  • Limonene is found in optically active forms in both the levoand dextro-rotatory forms as well as the optically inactive or racemic-form known as dipentene.
  • the optically inactive limonene or dipentene occurs in various wood turpentines.
  • d-Limonene has been identified in oil of orange (about 90 percent), lemon, mandarin, lime, grapefruit, bergamot, neroli, petitgrain, elemi, caraway, dill, fennel, celery, orthodon oils, etc.
  • l-Limonene occurs in several pine needle oils, the cone oil of Abies alaba, Russian turpentine oil, star anise, American wormseed, peppermint, spearmint, cajeput, Eucalyptus staigeriana, Congo copal resin, etc.
  • limonene separation Separation of the limonene from essential oils is well known and need not be set out in detail here.
  • two methods of obtaining limonene are (l) by fractional distillation; or (2) via certain crystalline adducts, e.g., the tetrabromides, which regenerate the hydrocarbons on debromination with zinc and acetic acid.
  • d-Limonene, l-limonene, and dl-limonene are all commercially available, though, and the isolation or preparation of the starting material forms no part of this invention.
  • optically active forms of limonene i.e. dand l-limonene and the optically inactive form, i.e. dl-limonene undergo the same chemical reactions and that the products obtained from each form differ only in optical activity.
  • products obtained through this invention from the optically active forms are optically active while racemic limonene forms optically inactive products.
  • the optically active form of limonene used as the starting reactant would be dictated only by the absolute stereochemistry desired for the final product-It has been found that no loss of optical purity occurs during the conversion of either dor l-limonene to the stable intermediate, metalated limonene, and subsequent reactions to the final product desired. No racemization during the reactions has been detected. This is quite important where production of compounds with a specific configuration is desired. For instance, the naturally occurring ,B-bisabolene and lanceol are known to occur in nature only in the levo-form. Thus in any strict reconstitution of an essential oil containing either of these two materials it would be necessary to synthesize the levo-form. However, it should be recognized that the absolute configuration of a material is not always of importance and hence in such cases the stereochemical form of the limonene to be used is of little concern.
  • limonene is metalated by use of a strong metalating agent, for example, a complex of n-butyllithium and N,N,N',N'-tetramethylethylenediamine (TMEDA) which is suggested as a strong metalating agent in recent published articles by Langer in Trans. NY. Acad. Sci, Ser. V. 27, 741 (1965) and Eberhardt and Butte, J. Org. Chem. 29, 2928, (1964).
  • TEDA N,N,N',N'-tetramethylethylenediamine
  • That metalation of limonene at the side chain position occurs is proved by derivatization of the reaction product to form known and/ or identifiable products.
  • the mixture obtained by allowing excess limonene to react with the n-butyllithium-TMEDA complex was treated with carbon dioxide.
  • the product consisted predominantly of the fin -unsaturated ester represented by 111 in the following schematic equations:
  • This set of reactions shows that limonene undergoes metalation at the methyl group attached to the side-chain double bond to form an organolithium species represented by II.
  • This intermediate reacts as an allylic carbam'on on derivatization with resultant substitution of a new group for a hydrogen atom found on the aforementioned methyl group.
  • metalation of limonene is quite distinct in that metalation occurs at a position adjacent to only one of the olefinic bonds as noted from the above schematic equations, a result not predictable. This feature is quite important in that it allows the synthesis of very specific compounds without contamination from unrelated byproducts. Another important characteristic of the metalated limonene is that it is stable and can be stored at length prior to further reactions with various reagents.
  • the optical activity or configuration of the limonene depends only on the desired configuration of the product to be formed. If the absolute stereochemistry of the product is unimportant no care need be taken in the selection of the starting limonene.
  • organolithium reagents can be used as the metalating agent.
  • the organolithium is a primary alkyllithium having from 2 to carbon atoms.
  • ethyllithium n-propyllithium, or n-butyllithium are suitable.
  • n-butyllithium is used as the organolithium in the metalating agent.
  • ditertlary amine forms an important part of the metalating agent.
  • the diamine contains 1 to 4 carbon atoms between the two amino groups.
  • TMEDA, DABCO, and sparteine are the preferred tertiary amines.
  • the most preferred tertiary amine is T MEDA.
  • organolithium is required for each equivalent of limonene.
  • a greater ratio of organolithium to limonene can be used, but slnce the organolithium is an expensive chemical a large excess is preferably avoided.
  • excess limonene can be used with any non-reacted limonene being recovered by distillation prior to final purification of the product.
  • the upper limit of the ratio of limonene to the organolrthium is only governed by the limitations imposed by having to separate the unreacted limonene from the final product.
  • the range of rat1os based on mole equivalents of limonene to organolithium is preferably from one to ten equivalents of limonene for each one equivalent of organolithium.
  • the most preferred ratio for the metalation process is two equivalents of limonene for each equivalent of organolithium.
  • the most preferred ratio of organolithium toamine has been found to be a 1:1 ratio based on mole equivalents.
  • the metalation reaction of the present invention can be carried out by the following procedure.
  • T o a container is charged a measured quantity of an organolithium in an inert solvent. While the solution is maintained under an atmosphere of dry inert gas, such as nitrogen or argon, the ditertiary amine is added. The solution should be stirred while the addition is made. Limonene is added dropwise to the resulting solution. The resulting mixture is allowed to stand under inert atmosphere for a length of time sufficient to insure a substantial completion of the reaction. Derivatization of the intermediate metalated limonene can now be effected by the direct reaction of the solution with the appropriate reagent, followed by standard work-up procedures. Excess limonene, if any, can be recovered by distillation prior to final purification of the product.
  • the metalated limonene of the present invention can be isolated by evaporating the solution containing metalated limonene to dryness in vacuo. Normally, it is inconvenient to do so since the metalated limonene is employed as an intermediate in the preparation of other compounds by subsequent reactions.
  • the reactants are preferably kept free from oxygen and moisture. For this reason a blanket of dry inert gas is maintained above the solution, such as nitrogen or argon as above mentioned.
  • these gases are but two examples of many gases that can be used. The primary criteria being that the gas preferably be free of moisture and inert.
  • any solvent that is used for the process should preferably be inert.
  • the preferred solvents are the alkanes and cycloalkanes. Alkanes having having 5 to 10 carbon atoms have been found to be very suitable for the present invention. The most preferred alkane solvent is n-hexane. Cycloalkanes of from 5 to 10 carbon atoms also can be used as a solvent in the metalation reaction with cyclohexane being the most preferred solvent of the cycloalkanes.
  • the amount of solvent used in the metalation reaction is not critical.
  • the main consideration as to the concentration is the fact that as the dilution increases the reaction rate slows down. It has been found that when undiluted amine and limonene are added to the organolithium solution as described in the sequence above, an amount of solvent can be mixed with the organolithium prior to any limonene or amine additions to make an organolithium solution as dilute as 0.1 molar. A preferred concentration range based on the organolithium is 0.1 to 2 molar. The most preferred amount of solvent is an amount sufiicient to make a 1.5 molar solution of organolithium.
  • the metalation reaction is generally substantially finished after a time ranging from 1 to 24 hours depending on the temperature used. The most preferred time and temperature conditions for the reaction 32c (1:2;24 hours and room temperature (20 C. to
  • fi-bisabolene One of the advantages of forming fi-bisabolene according to the present process is that it can be produced by a one step process. That is, after limonene is metalated to the stable intermediate, metalated limonene, it does not have to be separated from the reaction mixture but rather, the desired reactant can simply be added with formation of the desired final product. Subsequent separation techniques are used to purify the final product.
  • a process for the production of IV is carried out using metalated limonene as the starting reactant.
  • Metalated limonene is produced in the manner discussed above.
  • l-halo- 3 methyl-2-butene is added dropwise.
  • An atmosphere of inert gas is maintained during this addition.
  • the rate of addition is adjusted so as to maintain the solution in a cooled state during the exothermic reaction.
  • After the addition is complete the mixture is allowed to warm to room temperature and water is added dropwise.
  • the organic phase is next diluted with ether and separated. The aqueous solution is extracted with ether.
  • the combined organic solutions are washed successively with aqueous sodium chloride, e.-g., hydrochloric acid, e.g. 3 M, aqueous sodium bicarbonate, e.g. 5%, again with aqueous sodium chloride, and dried and evaporated.
  • aqueous sodium chloride e.-g., hydrochloric acid, e.g. 3 M
  • aqueous sodium bicarbonate e.g. 5%
  • Excess limonene if any, is separated from the resulting liquid by distillation.
  • the colorless oil that remains comprises fl-bisa boleneand 4,4-dimethyl 2 (4-methylcyclohex-3-en-l-yl)-hexa-1,5- diene.
  • the reaction of the halide with metalated limonene is instantaneous and exothermic; thus, the reaction should be carried out at a reduced temperature.
  • Temperatures as high as the boiling point of any inert solvent that is used can be employed but the preferred temperature range is 70 C. to 25 C. the most preferred temperature range is -70 C. to -20 C.
  • the metalated limonene can also he used as an intermediate in the synthesis of a compound that is not only useful in itself, but also in the synthesis of other known and useful compounds.
  • the oxygenation of metalated limonene followed by reduction of hydroperoxide intermediates is represented by the following schematic route:
  • the alcohol V has been found to have a camphoraceous, minty, soapy, piney aroma and thus finds use as perfume material. Also it can'be used in the synthesis of lanceol as reported by Ruegg et al., supra. Lanceol'itself occurs naturally in the levo-form and hence if it is desired'to obtain this specific optical configuration, l-lirnonene must be used as the starting reactant in the metalation process.
  • the acetate derivative of V has been reported as a constituent in many citrus oils and is also useful as an ingredient in soap perfumes.
  • the acetate'derivativ'e is represented by the following:
  • metalated limonene can be used in' the synthesis of 9-carboxy-pmentha-1,8 10) -diene and 9-carbomethoxy-p-menta-l,8 (10)-diene.
  • the reactions proceed as represented by the following schematic formulas:
  • a portion of a rnetalated solution prepared in the manner. above described is'added rapidly to a slurry of Dry Ice in ether, or in the alternative, carbon dioxide gas is passed through a cooled metalated limonene solution.
  • a rnetalated solution prepared in the manner. above described is'added rapidly to a slurry of Dry Ice in ether, or in the alternative, carbon dioxide gas is passed through a cooled metalated limonene solution.
  • the ether solution can be dried and evaporated to recover any excess limonene.
  • the aqueous solution is acidified with dilute hydrochloric acid, extracted with ether and then the ether solution is dried and evaporated to give the acidification product, VI.
  • a solution of this material in methanol containing sulfuric acid is heated to reflux, cooled, and poured into water. The resulting mixture is extracted with ether, and the resulting ether solution then washed with dilute aqueous sodium bicarbonate, water and dried and evaporated
  • the carbonation reaction of metalated limonene is exothermic and occurs instantaneously.
  • the temperature during the carbonation should remain below 25 C., though it is possible to use higher temperatures.
  • the preferred temperature range when carbon dioxide gas is passed into a metalated limonene solution is 70 C. to '+25 C.
  • the above reactions involving the metalated limonene are preferably conducted in an atmosphere free from air or moisture to avoid unwanted by-products.
  • Example I metallation of limonene.
  • To the stirred solution was added dropwise 45 ml. (35 g., 0.30 mole) of dry TMEDA. A crystalline precipitate formed during the mildly exothermic reaction, which redissolved when the addition was complete.
  • Metalated limonene is isolated by evaporating the solution to dryness in vacuo.
  • organolithiums such as ethyllithium or n-propyllithium as well as other ditertiary amines such as tetramethymethylenediamine, tetramethylpropylenediamine, sparteine, or DA-BCO can be substituted on an equal mole basis for the n-butyllithium and/ or T MEDA, respectively, with equivalent results, i.e. metalated limonene is formed.
  • Example II (fi-bisabolene formation).
  • a solution of metalated limonene was prepared in the manner described above from '67 ml. (0.10 mole) of 1.5 M n-butyllithium in n-hexane, ml. (-11.7 g., 0.10 mole) of TM-EDA, and 33 ml. (27.7 g.,- 0.20 mole) of l-limonene.
  • the reaction flask was fitted with a low temperature thermometer and a pressure equalized addition funnel. The solution was stirred and cooled to 60 C. while static argon atmosphere in the system was maintained. 15.2 g.
  • Example III -A procedure similar to Example II was carried out using d-limonene. d-fi-Bisabolene was obtained having spectral properties identical with those of the l-enantiomer.
  • Example IV -(oxygenation of metalated limonene).
  • a solution of metalated limonene was prepared in the manner of Example I from 50 ml. (0.075 mole) of 1.5 M n-butyllithium in hexane, 11.25 ml. (8.77 g., 0.075 mole) TMEDA, and 25.0 ml. (21.0 g., 0.154 mole) of dlimonene.
  • the reaction flask was fitted with a low tem perature thermometer and a gas inlet tube extending beneath the surface of the liquid. The solution was stirred and cooled to 35 "C. while static argon pressure in the system was maintained.
  • Air which was first passed through a column of Drierite, was bubbled through the solution via the gas inlet tube, and the rate of addition of air was regulated so that the solution temperature did not exceed 20 C.
  • the cooling bath was removed and the solution was allowed to warm to room temperature (the air addition was stopped when the temperature reached 0).
  • dropwise addition of 15 ml. of water a solution of 18 g. of sodium sulfite in 70 ml. of water was added, and the resulting two-phase mixture was stirred vigorously for 17 hrs.
  • the layers were separated, and the aqueous solution was extracted with three portions of ether.
  • the combined organic solutions were washed successively with ml.
  • Example V carbonation of metalated limonene.
  • a solution of metalated limonene was prepared in the manner of Example I from 40 ml. (0.064 mole) of 1.6 M n-butyllithium in n-hexane, 9.6 ml. (7.5 g., 0.065 mole) TMEDA, and 21.2 ml. (17.8 g., 0.13 mole) of dlimonene.
  • a 60-ml. portion of this solution was added rapidly by syringe to a slurry of Dry Ice in ether. When the resulting mixture had warmed to room temperature, water 'was added, the layers were separated, and the aqueous layer was extracted with two additional portions of ether.
  • the combined ether solutions were dried and evaporated to give 10.2 g. of recovered limonene.
  • the aqueous solution was acidified with dilute hydrochloric acid, extracted three times with ether, and the combined ether solutions were dried and evaporated to give 6.0 g. of the liquid acid VI. 9-carboxy-p-mentha-l, 8(l0)diene.
  • a solution of this material in 100 ml. of methanol containing 1 ml. of concentrated sulfuric acid was heated to reflex for 2.5 hr., cooled, and poured into water. The resulting mixture was extracted with three portions of ether, and the combined ether solutions were washed successively with dilute aqueous sodium bicarbonate, Water, and'were dried and evaporated.
  • Fractional distillation of the residue (5.3 g.) through a short Vigreux column gave a total of 1.98 g. (19% based on n-butyllithium, 25% based on limonene consumed) of 9-carbornethoxy-pmentha-1,8(10)-diene as a colorless oil in three fractions: fraction 1, 0.93 g., B.P. 6267 C. (0.2 mm.); fraction 2, 0.61 g., B.P. 6775 C. (0.2 mm fraction 3, 0.44 g., B.P. 75-9l C. (0.2 mm.).
  • the purities of these fractions determined by GLPC were 92%, 90%, and 72%, respectively.
  • the analytical sample was obtained from fraction 1 by preparative GLPC. This methyl ester was found to possess a fruity, musty, earthy, floral, minty, fatty, sharp aroma.
  • a process of producing 2-(4-methylcyclohex-3-en-lyl)allyllithium comprising contacting limonene with a strong metalating agent consisting of a primary al-kyllithium having from 2 to 10 carbon atoms and a ditertiary amine having from 1 to 4 carbon atoms between the amino groups.

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3971827A (en) * 1974-09-09 1976-07-27 G. D. Searle & Co. Manufacture of poly-(cis)-isoprenols
US20060270863A1 (en) * 2005-05-27 2006-11-30 Amyris Biotechnologies Conversion of amorpha-4,11-diene to artemisinin and artemisinin precursors

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ATE155164T1 (de) * 1991-08-21 1997-07-15 Procter & Gamble Lipase und terpen enthaltende waschmittelzusammensetzungen

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3971827A (en) * 1974-09-09 1976-07-27 G. D. Searle & Co. Manufacture of poly-(cis)-isoprenols
US20060270863A1 (en) * 2005-05-27 2006-11-30 Amyris Biotechnologies Conversion of amorpha-4,11-diene to artemisinin and artemisinin precursors

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