JPH0149136B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to polyprenylamines. More specifically, the invention relates to the general formula (In the ceremony

[Formula] is a transformer type represents the soprene unit,

[Formula] represents a cis isoprene unit, n represents an integer from 11 to 19, R ¹ and R ² are the same or different,
Hydrogen atom, lower alkyl group, cycloalkyl group,
It represents an aryl group or an aralkyl group, or R ¹ and R ² are bonded to each other and have 2 to 2 carbon atoms.
5 represents an alkylene group. ) Regarding a novel polyprenylamine represented by The polyprenylamine 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 human kidneys by JFPennock et al. in 1960 [see Nature (London), 186 , 470 (1960)], and were later developed into general formula (A). [During the ceremony,

[Formula] represents a trans isoprene unit,

[Formula] represents a cis isoprene unit. The same shall apply hereinafter in this specification. ] is 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=
It was revealed that three homologs 14, 15, and 16 were the main constituents [RWkeenan et 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
[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 [J. Burgos et al., Biochemical
Journal, 88 , 470 (1963)]. Total synthesis of dolichols is extremely difficult using current organic synthesis techniques, as is clear from 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 polyprels (k = 4 to 6) (these are called betulaprenols) can be collected from Betula verrucola, but from these polyprels, cis-isoprene units are It is almost impossible to synthesize dolichols, which mainly have numbers 14, 15, and 16, 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 polyprenylacetate. Furthermore, DFZinkel et al. reported the presence of _C90 polyprenols with 18 isoprene units or an average value of 18 isoprene units in the leaf extract 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 hydrolyzed the extracts extracted from Japanese yam and Himalayan cedar using organic solvents as necessary, 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, with the exception of the absence of α-terminal saturated isoprene units, of which the polyprenyl fraction is optionally a constituent. It can be relatively easily separated into individual polyprenyl analogues (with a uniform number of isoprene units), and therefore the polyprenyl fraction and each polyprenyl analogue separated therefrom can be used as synthetic intermediates for 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 polyprenylamine represented by the general formula () which is useful as an intermediate in the following. The polyprenylamine of the present invention represented by the general formula () [hereinafter referred to as polyprenylamine ()]. ] is a general formula (In the formula, a halogen atom is represented, and n is as defined above.) Polyprenyl halide [hereinafter referred to as polyprenyl halide ()]. ] in the presence of a basic compound. (In the formula, R ³ represents a lower alkyl group.) Acetoacetate [hereinafter referred to as acetoacetate ()]. ] General formula () obtained by reacting with (In the formula, R ³ and n are as defined above.) Polyprenyl ketocarboxylic acid ester [hereinafter referred to as polyprenyl ketocarboxylic acid ester ()]. ] by saponifying and decarboxylating the general formula () In the formula, n is as defined above. ) Polyprenylacetone [hereinafter referred to as polyprenylacetone ()] ], and the polyprenylacetone is expressed by the general formula () (In the formula, R ⁴¹ and R ⁴² are the same or different,
Represents a methyl group or an ethyl group. ) [hereinafter referred to as Wittzig reagent ()
It is written as ] and Wittig reaction gives the general formula () (In the formula, n and R ⁴¹ are as defined above.) Polyprenylcarboxylic acid ester [hereinafter referred to as polyprenylcarboxylic acid ester ()]. ] and hydrolyze it to obtain the general formula () (In the formula, n is as defined above.) Polyprenylcarboxylic acid [hereinafter referred to as polyprenylcarboxylic acid ()]. ], and the polyprenylcarboxylic acid () or its reactive derivative such as an acid halide or acid anhydride is represented by the general formula (). (In the formula, R ¹ and R ² are as defined above.) An amine represented by [hereinafter referred to as amine ()]. ]
The general formula () obtained by reacting with (In the formula, n, R ¹ and R ² are as defined above.) Polyprenylcarboxylic acid amide [hereinafter referred to as polyprenylcarboxylic acid amide ()]. ] can be produced by reducing. By using its homologue mixture as polyprenyl halide () in this production method, polyprenylamine () is produced as the final product.
It is also possible to obtain a mixture of R ¹ in the general formulas (), () and ()
and R ² are the same or different, and are hydrogen atoms or lower alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, or cyclopentyl, cyclohexyl, etc. It is a cycloalkyl group, a phenyl group, an aryl group such as a tolyl group, or an aralkyl group such as a benzyl group, or R ¹ and R ² are bonded to each other and have 2 or more carbon atoms.
Forms 5 alkylene groups. Further, in the general formulas () and (), R ³ is a lower alkyl group such as a methyl group, an ethyl group, a propyl group, and a butyl group. 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.) A polyprenol represented by the formula 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-ptoxide, potassium t-ptoxide, sodium methoxide, and sodium ethoxide;
Preferred are hydroxides or alkoxides, such as n-butyllithium and methyllithium. The basic compound is generally used in an amount of about 0.1 to 5.0 mol, preferably 0.5 to 3.0 mol, and more preferably 0.7 to 1.5 mol per mol of acetoacetate (). 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 the anion of acetoacetate () is formed, nitrogen gas,
-30℃＋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 usually about 10 minutes to 5 hours is sufficient. 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 in the range from -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 0
Preferably, the reaction temperature is within the range of 80°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, but is usually about 30 minutes. Approximately from 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. It is especially conveniently used in chromatography. Adsorbents that can be used for chromatography include silica gel, alumina, activated carbon, and cellulose. Among them, 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
It is desirable that the amount is 1.0 to 20.0 molar equivalents, preferably 1.5 to 10.0 molar equivalents. Hydrous alcohols such as those mentioned above are suitable as reaction solvents, but hexane, pentane, benzene,
It is also preferable to add a small amount of a hydrocarbon solvent such as toluene. 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 to complete the reaction varies depending on the temperature conditions employed at this time, but is usually within a 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,
A mixture of a small amount of a polar solvent such as chloroform, ethyl acetate, or methyl acetate is suitable. The Witzig reaction between polyprenylacetone () and Witschich reagent () is usually carried out in a solvent. Examples of suitably used solvents include dimethylformamide, tetrahydrofuran, and diethyl ether. In order to allow 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 desirable to replace the reaction system with an inert gas such as nitrogen or argon. There is no particular restriction on the amount of solvent used, but generally about 5 to 50 parts by weight, preferably 10 to 30 parts by weight, of the solvent is used per 1 part by weight of polyprenylacetone (). Particularly preferred examples of the Witzig reagent (2) include the following compounds. When carrying out the Witchig reaction, it is necessary to form a phosphorylide by treating the Witchig reagent () with a basic compound. Examples of basic compounds suitably used for this purpose include n-butyllithium, methyllithium, etc. , sodium hydride, potassium hydride, sodium methoxide, sodium ethoxide, and the like.
After adding such a basic compound into the above-mentioned solvent, the temperature is about -30°C to +80°C, preferably -10°C to +80°C.
While stirring at a temperature of 50°C, the Witzig reagent is added dropwise to the mixture, and after the dropwise addition is completed, stirring is continued for about 0.5 to 24 hours in the above temperature range to form a phosphorylide. The amount of the basic compound to be used in this case is preferably about 0.5 to 1.5 molar equivalents based on Witzig's reagent (2). Polyprenylcarboxylic acid ester () can be obtained by adding polyprenylacetone () to this phosphorylide solvent and reacting at about 0°C to 100°C, preferably 15°C to 80°C. The reaction time required to complete this reaction generally ranges from about 0.5 to 24 hours. The amount of Wittzig reagent () to be used is 0.5 to 10.0 molar equivalent to polyprenylacetone (), preferably
The amount is 0.8 to 8.0 molar equivalents, more preferably 1.0 to 5.0 molar equivalents. The obtained polyprenylcarboxylic acid ester () can be purified by various methods based on known separation and purification methods, but purification by chromatography is particularly convenient. As adsorbents and developing solvents for chromatography, the adsorbents and developing solvents mentioned above in the case of purification of polyprenylacetone (2012) are similarly used. The hydrolysis reaction of polyprenylcarboxylic acid ester () is carried out according to the method applied to the hydrolysis reaction of ordinary fatty acid esters. For example, polyprenylcarboxylic acid ester () can be recovered by stirring it in aqueous ethanol with about 2 to 5 times the molar amount of sodium hydroxide relative to the polyprenylcarboxylic acid ester () under reflux conditions for about 1 to 5 hours. Polyprenylcarboxylic acid () can be obtained with high efficiency, and can be easily purified by chromatography using the adsorbent and developing solvent described above in the case of purifying polyprenylacetone (). Polyprenylcarboxylic acid () and amine ()
The amide synthesis can be carried out by a commonly known method. For example, it can be carried out using a dehydration condensation agent such as N,N'-dicyclohexylcarbodiimide, N,N'-diethylcarbodiimide, phosphorous acid trialkyl ester, or phosphorus oxychloride. Easy to use. This reaction is preferably carried out in a solvent. Suitable solvents include halogenated hydrocarbon solvents such as methylene chloride and chloroform. The amount of solvent used is not critical, but is 2 to 100 times (by weight), preferably 5 to 50 times (by weight) based on the amount of polyprenylcarboxylic acid (2). It is preferable to use a sufficiently dried solvent in order to allow the intended reaction to proceed smoothly. Approximately 1 molar equivalent of N,N'-dicyclohexylcarbodiimide and amine () to polyprenylcarboxylic acid () is sufficient. The reaction temperature is preferably from -20°C to the boiling point of the solvent, more preferably from 0°C to room temperature. Although the reaction time varies depending on the temperature conditions used, 1 to 2 hours is usually sufficient. In a preferred embodiment, a solution of polyprenylcarboxylic acid () in methylene chloride is added with N,
Slowly add N'-dicyclohexylcarbodiimide, stir for 15-30 minutes, then slowly add amine () and slowly warm to room temperature. After separating the floating solids and pouring the resulting solution into cold water, the organic layer was separated, washed sequentially with dilute hydrochloric acid, water, saturated sodium bicarbonate solution and saturated brine, and the organic layer was dried. When the solvent was distilled off, polyprenylcarboxylic acid amide was obtained. A crude product of () is obtained. Purification of this product can be easily carried out by chromatography using the adsorbent and developing solvent described above in the case of purification of polyprenylacetone (). Suitable reducing agents for reducing polyprenylcarboxylic acid amide () to polyprenylamine () include metal hydrogen complex compounds such as lithium aluminum hydride, sodium aluminum hydride, sodium borohydride, and lithium borohydride. used for. The amount of the reducing agent used depends on the reducing agent used, but is generally 0.5 to 10 equivalents, preferably 1 to 5 equivalents, relative to polyprenylcarboxylic acid amide (). This reduction reaction is carried out in a suitable solvent. Examples of reducing agents include ether solvents such as diethyl ether and tetrahydrofuran when lithium aluminum hydride is used as the reducing agent, and alcohol solvents such as ethanol and isopropanol, and pyridine when using sodium borohydride. The temperature for the reduction reaction is usually around the boiling point of the solvent, and the reaction can be completed by stirring for about 2 to 20 hours under this temperature condition. Isolation and purification of polyprenylamine () is usually performed by known separation and purification methods, but chromatography is preferably employed. Adsorbents used in chromatography include silica gel, alumina, activated carbon, and cellulose, with silica gel or alumina being preferred. As developing solvents, hydrocarbon solvents such as hexane, pentane, petroleum ether, and benzene, diethyl ether,
A mixture containing a small amount of a polar solvent such as diisopropyl ether, chloroform, ethyl acetate, ethanol, or n-butylamine is suitable. For example, from a polyprenylamine in which R ¹ and R ² are not hydrogen atoms in the general formula (), the synthetic route shown below [hereinafter referred to as synthetic route (i)] can be obtained. ] can also synthesize mammalian dolichols. However, in the above formula, PP is the formula (In the formula, n is as defined above.) In this specification, the same applies hereinafter. R ¹ and R ² are as defined above except for the hydrogen atom. The reaction is allylamine () enamine (XII)
It is an isomerization reaction to, for example, rhodium ()
It is carried out by hydrogen transfer using a complex catalyst. At this time, as a rhodium () complex with an optically active diphosphine ligand, [Rh
(diphosphine) (1,5-cyclooctadiene)]
When ClO ₄ is used, asymmetric hydrogen transfer occurs and it is also possible to obtain optically active enamine (XII). The reaction is a hydrolysis reaction of the obtained enamine (XII), which is carried out, for example, by treatment with dilute hydrochloric acid water, and the resulting polyprenyl aldehyde (XII) is reduced (reacted) with, for example, sodium borohydride, and then the mammalian Dolichols (XI)
can be synthesized. For example, from a polyprenylamine in which only R ¹ is a hydrogen atom in the general formula (), the synthetic route shown below [hereinafter referred to as synthetic route (ii)] can be obtained. ] can also synthesize mammalian dolichols. In the above formulas () and (), R ² is as defined above except for the hydrogen atom. Reaction 1' is isomerization by hydrogen transfer reaction using, for example, a rhodium () complex catalyst, as in synthetic route (i), and polyprenylimine () is thereby obtained. Reaction 2′ is also similar to synthetic route (i), and a hydrolysis reaction is carried out by treatment with dilute hydrochloric acid water to form polyprenylaldehyde (), which is reduced (reacted) with sodium borohydride to form mammalian dolichols (XI). can lead to. In the general formula (), both R ¹ and R ² are hydrogen atoms, and the polyprenylamine is reacted with excess methyl iodide in methanol or ethanol in the presence of a basic catalyst, and the polyprenylamine is reacted with the general formula () (In the formula, n is as defined above.) Polyprenyltrimethylammonium salt [hereinafter referred to as polyprenyltrimethylammonium salt ()]. ], this can be reductively demethylated to convert it into a polyprenylamine with R ¹ = R ² = CH ₃ in the general formula (), and then lead to mammalian dolichols according to the above synthetic route (i). can. 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. The 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 immersion 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, the residue was extracted with diethyl ether (500 ml), and the ether layer was extracted with about 100 ml. After washing with water five 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 Polyprel with a purity of 95% or more, and it is processed using a semi-preparative high-performance liquid chromatography column manufactured by Merck & Co., Ltd.
High performance liquid chromatography analysis was performed using LiChrosorbRP18-10 (C ₁₈ type) using a mixed solvent of acetone/methanol = 90/10 (volume ratio) as the eluent and a differential refractometer as a detector. The results of determining the area ratio of each peak in the chromatogram are as follows.

【table】

[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 ¹³ C
-NMR spectrum confirmed that these components were polyprenol having a structure represented by general formula (XI). Field ionization mass spectrometry (FD-
Table 1 shows the results of MASS) and the δ value of ¹ H-NMR.
^{The 13} C-NMR values δ 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, n represents an integer from 11 to 19, R ¹ and R ² are the same or different,
Hydrogen atom, lower alkyl group, cycloalkyl group,
It represents an aryl group or an aralkyl group, or R ¹ and R ² are bonded to each other and have 2 to 2 carbon atoms.
Represents 5 alkylene groups. ) Polyprenylamine.