JPH022864B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to polyprenyl aldehydes. More specifically, the invention relates to the general formula (In the formula, [Formula] represents a trans-type isoprene unit, [Formula] represents a cis-type isoprene unit, and n represents an integer from 11 to 19.) The polyprenyl aldehyde represented by the general formula () provided by the present invention is a substance useful as a raw material for medicines, cosmetics, etc., and is particularly useful as a synthetic intermediate for mammalian dolichols. Dolichols were first isolated from pig liver in 1960 by JEPennock et al. [Nature
(London), 186 , 470 (1960)], which was later changed to general formula (A) [In the formula, [Formula] represents a trans isoprene unit, and [Formula] represents a cis isoprene unit. The same shall apply hereinafter in this specification. ] A mixture of polyprenol homologs having the structure shown in formula (A), where j representing the number of cis isoprene units generally ranges from 12 to 18, and j
= 14, 15, and 16 were found to be the main congeners [RWKeenan et al.
al., Biochemical Journal, 165 , 505 (1977)]. Dolichols are widely distributed not only in the liver of pigs but also in the bodies of mammals, and are known to play extremely important functions in maintaining the life of living organisms. For example, JB Harford et al. conducted an in vitro study using the white medulla of calves and pigs' brains, and found that exogenous dolichol promotes the incorporation of sugar components such as mannose into lipids, which are important for maintaining the life of living organisms. [Biochemical
and Biophysical Research Communication;
76, 1036 (1977)]. The effect of dolichols on promoting the incorporation of sugar components into lipids is more pronounced in already mature animals than in growing organisms, so the role of dolichols in preventing aging is attracting attention. Also, RW
Keenan et al. state that it is important for rapidly growing organisms, such as those in childhood, to ingest dolichol from outside and supplement the dolichol obtained by biosynthesis within the body [Archives of
Biochemistry and Biophysics, 179 , 634 (1977)
reference〕. Furthermore, Akamatsu et al. quantified dolichol phosphate ester in the regenerated liver of rats and found that the amount was significantly reduced compared to that in the normal liver, indicating that the glycoprotein synthesis function in the liver tissue was greatly reduced. We found that the function was improved by externally adding dolichol phosphate [presented at the 54th Annual Meeting of the Japanese Biochemical Society (1981)]. As mentioned above, dolichols are substances that control extremely important functions for living organisms, and are useful as pharmaceuticals or intermediates thereof. Only 0.6 g of dolichol can be obtained through this process [FW Burgos et al., Biochemical
Journal, 88 , 470 (1963)]. It is extremely difficult to completely synthesize dolichols using current organic synthesis techniques, as evidenced by their complex and unique molecular structures. It would be advantageous if dolichols could be obtained by relying on natural products as synthetic intermediates and adding simple synthetic chemical treatments to them, but such convenient substances have not been found so far. Conventionally, the following general formula (B) [However, it is known that polyprenols represented by k = 4 to 6 (these are called betulaprenols) can be collected from Betula verrucola; It is almost impossible to synthesize dolichols mainly containing 14, 15, and 16 molecules using current organic synthesis techniques. Also
K. Hannus et al.
reported that a polyprenyl component was isolated from leaves of S. sylvestris at a yield of 1% on a dry weight basis, and that this component was a polyprenyl acetate mixture containing 10 to 19 isoprene units primarily in the cis configuration. Phytochemistry, 13 , 2563 (1974)], their report does not elucidate the details of the trans and cis configurations in the polyprenyl acetate. Furthermore, DFZinckel et al. reported the presence of C ₉₀ polyprenols with 18 isoprene units or an average number of isoprene units in extracts of leaves of Pinus strobus [ Phytochemistry,
11, 3387 (1972)], this report does not provide a detailed analysis of the trans and cis configurations of the polyprenol. Some of the present inventors and their co-researchers first performed hydrolysis, if necessary, of extracts extracted from Japanese yam and Himalayan cedar using organic solvents, and then used chromatography, fractional dissolution, and other methods. 14 by treatment with a suitable separation method.
A polyprenyl fraction consisting of a polyprenol and/or a mixture of its acetate homologues having ~22 isoprene units in exactly the same trans, cis configuration as mammalian dolichols is obtained; In contrast, the polyprenyl fraction exhibits a distribution of polyprenyl congeners very similar to that in mammalian dolichols, only with the absence of α-terminal saturated isoprene units; It can be relatively easily separated into certain individual polyprenyl analogues (with a uniform number of isoprene units), and therefore, the polyprenyl fraction and each polyprenyl analogue separated therefrom are both synthetic intermediates of mammalian dolichols. I found it to be very suitable. In order to efficiently produce mammalian dolichols using the above-mentioned polyprenyl compounds, the present inventors have intensively investigated a method of introducing a saturated isoprene unit into the α-terminus of the polyprenyl chain of the polyprenyl compound, and found that such a method The present invention was completed by creating a polyprenyl aldehyde represented by the general formula () which is useful as an intermediate in the following. Polyprenyl aldehyde represented by the general formula () [hereinafter referred to as polyprenyl aldehyde ()]. ]
is the general formula () (In the formula, a halogen atom is represented, and n is as defined above.) Polyprenylhaladehyde [hereinafter referred to as polyprenylhaladehyde ()]. ] in the presence of a basic compound. (In the formula, R represents a lower alkyl group.) Acetoacetate [hereinafter referred to as acetoacetate ()]. ] General formula () obtained by reacting with (In the formula, R and n are as defined above.) Polyprenylketocarboxylic acid ester [hereinafter referred to as polyprenylketocarboxylic acid ester ()]. ] is saponified and decarboxylated to give the general formula () (In the formula, n is as defined above.) Polyprenylacetone represented by the formula It can be produced by carrying out a Wittig reaction with a compound represented by and then removing the protecting group of the -CHO group in the product. As mentioned above, polyprenyl halide () has the general formula that can be obtained directly or through hydrolysis from extracts of Japanese yam or Himalayan cedar. (In the formula, n is as defined above.) Polyprenol or a mixture thereof is treated with a halogenating agent such as phosphorus trihalide such as PCl ₃ or PBr ₃ , or thionyl halide such as SOCl ₂ or SOBr ₂ to generate a halogen. It can be easily obtained by This halogenation reaction is usually carried out by dissolving the above-mentioned polyprenol in a suitable solvent such as hexane or diethyl ether, and then dissolving the polyprenol in the presence or absence of a base such as triethylamine or pyridine at about -20°C or more. This is done by adding a halogenating agent at a temperature of +50°C. The reaction between polyprenyl halide () and acetoacetate () is preferably carried out in a solvent. Suitable solvents include ether solvents such as diethyl ether, tetrahydrofuran, dioxane, and dimethoxyethane. The amount of the solvent used is not critical, but is 2 to 100 times (by weight), preferably 5 to 80 times (by weight), and more preferably 10 to 50 times (by weight) to the polyprenyl halide (). . It is preferable to use a sufficiently dried solvent in order to allow the intended reaction to proceed smoothly. In order to carry out this reaction, the presence of a basic compound is essential. The basic compounds used include alkali metal hydrides such as sodium hydride, potassium hydride, sodium hydroxide, potassium hydroxide, sodium t-butoxide, potassium t-butoxide, sodium methoxide, and sodium ethoxide;
Hydroxides or alkoxides, n-butyllithium, methyllithium, etc. are suitable. The basic compound is generally about 0.1 to 5.0 mol, preferably 0.5 to 3.0 mol per mol of acetoacetate ().
It is used in a molar ratio, more preferably 0.7 to 1.5 molar. In a preferred embodiment, the basic compound is first added to a solution or dispersion of the basic compound by adding the acetoacetate () or conversely to a solution of the acetoacetate () by gradually adding the basic compound all at once or in small portions. The anion of acetoacetate is formed and then polyprenyl halide () is added thereto and reacted. The ratio of acetoacetate () and polyprenyl halide () used is not critical, but the molar ratio of acetoacetate ()/polyprenyl halide () is 1/2 to 20/1,
Preferably it is 4/5 to 10/1, more preferably 1/1 to 5/1. When forming the anion of acetoacetate (), nitrogen gas,
-30℃ to +100 under inert gas atmosphere such as argon
It is desirable to carry out the reaction at a temperature of .degree. C., preferably -10.degree. C. to +80.degree. C., thereby allowing the desired anion to be smoothly formed while suppressing side reactions. The time required for this anion formation varies depending on the reaction temperature used, but is usually about 10 minutes to 5 minutes.
About an hour is enough. Polyprenyl halide () is added to the anionic solution of acetoacetate () prepared in this manner and reacted. Depending on the reaction conditions used, the reaction may be allowed to proceed smoothly by adding polyprenyl halide (2) in small portions or in a dropwise manner rather than adding the entire amount at once.
The temperature within the reaction system during the time of addition of polyprenyl halide () and thereafter until completion of the reaction is not critical, but is preferably within the range of -10°C to the boiling point of the solvent used. If the reaction temperature is too low, the reaction progresses slowly and takes too much time to complete the reaction. On the other hand, if the reaction temperature is too high, undesirable side reactions will proceed. From this point of view, it is preferable to employ a reaction temperature within the range of 0°C to 80°C. In order to complete the reaction after adding polyprenyl halide (), it is necessary to continue stirring the reaction mixture at the above reaction temperature, and the time required for this varies depending on the reaction temperature used. It takes about 30 minutes to 24 hours. In order to confirm the progress of the reaction, it is convenient and preferable to monitor the decrease in the raw material polyprenyl halide () by thin layer chromatography. After the reaction, isolation of the polyprenylketocarboxylic acid ester () from the reaction mixture can be easily accomplished by applying isolation methods used in conventionally known synthetic reactions. In particular, chromatography is conveniently used. Adsorbents that can be used in chromatography include silica gel, alumina, activated carbon, and cellulose. Among these, silica gel is particularly preferably used. As the developing solvent, a mixture of a small amount of a polar solvent such as diethyl ether, chloroform, ethyl acetate, or ethyl alcohol with a hydrocarbon solvent such as hexane, pentane, petroleum ether, or benzene is suitable. In addition, this isolation step is omitted and the next step, the synthesis reaction of polyprenylacetone (), is carried out directly.
It is also possible to carry out a purification step thereafter. Polyprenylketocarboxylic acid ester () can be saponified by applying the method conventionally used for the saponification reaction of higher fatty acid esters. For example, the objective can be achieved by stirring polyprenylketocarboxylic acid ester () with sodium hydroxide or potassium hydroxide in aqueous methanol, aqueous ethanol or aqueous isopropanol. The amount of sodium hydroxide or potassium hydroxide used is approximately 1.0 per polyprenyl ketocarboxylic acid ester ().
~20.0 molar equivalents, preferably 1.5 to 10.0 molar equivalents. The above-mentioned hydrous alcohols are suitable as reaction solvents, but a small amount of hydrocarbon solvents such as hexane, pentane, benzene, toluene, etc. may be added to increase the solubility of polyprenylketocarboxylic acid ester (). preferable. In order to allow the saponification reaction to proceed smoothly, it is desirable to adopt a reaction temperature ranging from 0°C to the boiling point of the solvent used, preferably within the range of 25 to 65°C. The time required for the reaction to complete is
Although it varies depending on the temperature conditions adopted at this time, it is usually within the range of about 0.5 to 24 hours. After carrying out the saponification reaction as described above,
Neutralize the reaction solution with a mineral acid such as hydrochloric acid or sulfuric acid, preferably under room temperature conditions or ice-cooled conditions, and then make the reaction solution acidic to a pH of about 1 to 3, and the decarboxylation reaction will automatically occur. , polyprenylacetone ()
is formed. After the decarboxylation reaction is completed, the reaction solution is extracted with hexane, benzene, diethyl ether, etc., thoroughly washed with water, the organic layer is dried, and the solvent is distilled off to obtain a crude product of polyprenylacetone (). Chromatography is preferably employed to purify this product. Adsorbents used in chromatography include silica gel, alumina, activated carbon, and cellulose, with silica gel being particularly suitable.
As developing solvents, hydrocarbon solvents such as hexane, pentane, petroleum ether, benzene, and toluene, diethyl ether, diisopropyl ether,
It is preferable to use a mixture of a small amount of a polar solvent such as chloroform, ethyl acetate, or methyl acetate. Polyprenylacetone () and formula The Witzig reaction with 1,3-dioxan-2-ylmethyltriphenylphosphonium bromide must be carried out in a solvent inert to this reaction. Examples of solvents that can be suitably used include dimethylformamide, tetrahydrofuran, diethyl ether, and benzene. In order for the desired reaction to proceed smoothly, it is preferable that the solvent used be sufficiently dried to an anhydrous state. Furthermore, from the same viewpoint, it is preferable to replace the reaction system with an inert gas such as nitrogen or argon. The solvent is 5 to 50% of the polyprenylacetone () used in the reaction.
It is preferable to use 10 to 30 times the amount by weight, especially 10 to 30 times the amount by weight. In the reaction using the Witchig reagent, in which an oxygen atom is present at the β-position of the phosphorus atom, in order to minimize the elimination reaction, which is a side reaction, a base is added dropwise to a mixture of the Witchig reagent and polyprenylacetone (2). Polyprenylacetone () as soon as the phosphorylide is generated from the reagent and base.
It is preferable to react with here,
Examples of the basic compound used include n-
Suitable examples include butyllithium, methyllithium, phenyllithium, sodium hydride, potassium hydride, lithium methoxide, sodium methoxide, sodium ethoxide, sodium amide, and the like. The basic compound selected from these is approximately 0.5 to 1.5 to the Wittzig reagent.
Add molar equivalent dropwise. At that time, the bath temperature is -30℃~+
The temperature is maintained at 120°C, preferably 20°C to 100°C, and stirring is continued for about 0.5 to 5 hours in the above temperature range to complete the reaction after the dropwise addition is completed. The amount of Witzig reagent used is based on polyprenylacetone ()
0.5 to 10.0 molar equivalents, preferably 0.8 to 8.0 molar equivalents,
More preferably, the amount is 1.0 to 5.0 molar equivalents. After the Witzig reaction is completed, the polyprenyl aldehyde (2) of the present invention can be obtained by treating with a mineral acid such as hydrochloric acid or sulfuric acid to remove the protecting group of the -CHO group. Alternatively, in the general formula (), n is
General formula (′) included in polyprenyl aldehyde () by direct oxidation of polyprenol which is 12-19 (In the formula, n is as defined above.) A polyprenyl aldehyde represented by the following can be obtained. As the oxidizing agent for this purpose, oxidizing agents that are normally used for oxidizing allyl alcohol to α,β-unsaturated aldehyde can be used, such as manganese dioxide, chromic anhydride-pyridine, pyridinium chlorochromate (PCC), Examples include pyridinium dichromate (PDC), and manganese dioxide is particularly suitable. The amount of oxidizing agent used is polyprenol ()
molar ratio of 1 to 200 times, preferably 2 to 100 times
It's double. This oxidation reaction is preferably carried out in a solvent, and an example of a suitably used solvent is methylene chloride. When using manganese dioxide as an oxidation example, halogenated hydrocarbons such as chloroform and carbon tetrachloride, hydrocarbons such as petroleum ether, hexane, pentane and benzene, ketones such as acetone and methyl ethyl ketone, diethyl ether and diisopropyl Ethers such as ether can also be suitably used. The amount of the above solvent used is not critical, but it is 1 to 200 times the weight of the polyprenol (), preferably 2 to 200 times the weight of the polyprenol ().
The amount is 100 times by weight, more preferably 5 to 50 times by weight.
The reaction temperature for carrying out this oxidation reaction is -30°C to +100°C, preferably -10°C to +60°C. In order to smoothly complete the reaction, it is necessary to stir the reaction mixture at the above-mentioned reaction temperature, and it is usually preferable to allow the reaction to occur for about 0.5 to 48 hours. In order to confirm the progress of the reaction, it is convenient and preferable to monitor the decrease in the raw material polyprenol () by thin layer chromatography. After the reaction is completed, the polyprenyl aldehyde () of the present invention can be obtained by filtering the reaction mixture and distilling off the solvent from the liquid. Polyprenyl aldehyde () can be purified by applying conventionally known separation and purification techniques. Chromatography is particularly preferred because it is simple. Examples of adsorbents used in chromatography include silica gel, alumina, activated carbon, florisil, and cellulose, with silica gel being particularly preferred. As a developing solvent, use a mixture of a hydrocarbon solvent such as hexane, pentane, petroleum ether, or benzene with a small amount of a polar solvent such as chloroform, methylene chloride, diethyl ether, diisopropyl ether, methyl acetate, ethyl acetate, or acetone. is suitable. The polyprenyl aldehyde represented by the general formula () synthesized in this manner is a new compound that has not been described in any literature, and is a useful compound as a raw material for the synthesis of mammalian dolichols. Mammalian dolichols can be synthesized from this compound, for example, by the synthetic route shown below. However, in the above formula, PP is the formula (In the formula, n is as defined above.) The reaction is - of polyprenyl aldehyde ()
This is a selective hydrogenation reaction of an isoprene unit having a CHO group, and is carried out using a hydrogenation catalyst such as palladium, nickel, or rhodium. The terminally saturated polyprenyl aldehyde () obtained is treated with a reducing agent such as lithium aluminum hydride to remove the −CHO group from −
Mammalian dolichols () can be obtained by reduction to the CH ₂ OH group. Hereinafter, the present invention will be explained in more detail with reference to Examples and Reference Examples. In addition, IR analysis in Examples and Reference Examples was measured using a liquid film, and NMR analysis was performed using TMS.
was measured as an internal standard. FD-MASS analysis values are values corrected as ¹ H, ¹² C, ¹⁶ O, and ⁷⁹ Br. Reference example 1 Separation of polyprenol 10 kg of fig leaves collected in Kurashiki City at the end of October
(undried weight) was dried with hot air at about 40°C for 24 hours, and then extracted by immersing it in chloroform 80 at room temperature (about 15°C) for one week. Petroleum ether 5 was added to the concentrate obtained by distilling off chloroform from this extract to separate insoluble components, and after concentrating the liquid, it was separated using a silica gel column using chloroform as a developing solvent to obtain about 37 g of an oily substance. Obtained. Approximately 400 ml of acetone is added to this oil to dissolve the acetone-soluble components, the resulting mixture is filtered, and the liquid is concentrated.
The obtained oil was heated at 65°C for 2 hours with 400 ml of methanol, 40 ml of water, and 20 g of sodium hydroxide, then the methanol was distilled off, and the residue was extracted with diethyl ether (500 ml), and the ether layer was extracted with about 100 ml. After washing with water 5 times, it was dried over anhydrous sodium sulfate, and the solvent was distilled off to obtain 24.2 g of an oily substance. Next, this oil was mixed with n-hexane/isopropyl ether = 90/10 using about 1 kg of silica gel.
(volume ratio) of the mixed solution to obtain 21.8 g of oil. This oily substance is polyprenol with a purity of 95% or more, and it is used on a semi-preparative high performance liquid chromatography column (Li Chrosorb) manufactured by Merck & Co., Ltd.
Using RP18-10 (C ₁₈ type), use a mixed solvent of acetone/methanol = 90/10 (volume ratio) as the eluent.
High performance liquid chromatography analysis was performed using a differential refractometer as a detector, and the area ratio of each peak in the obtained chromatogram was determined, and the results were as follows. [Table] Using this high-performance liquid chromatography, each component was separated from the above oily substance and analyzed by mass spectrometry, infrared absorption spectrum, ¹ H-NMR spectrum, and
It was confirmed by ¹³ C-NMR spectrum that these components were polyprenol having a structure represented by the general formula (). Field ionization mass spectrometry (FD-
MASS) results and ¹ H-NMR δ values are summarized in Table 1, and ¹³ C-NMR δ values are summarized in Table 2. [Table] [Table]

Claims (1)

[Claims] 1. General formula (In the formula, [Formula] represents a trans isoprene unit, [Formula] represents a cis isoprene unit, and n represents an integer from 11 to 19.) A polyprenyl aldehyde represented by the following formula.