JPS6357549A - Polyprenyl based compound - Google Patents

Abstract

NEW MATERIAL:A polyprenyl based compound expressed by formula I (n is 1-3; R<1> is H or lower alkyl; R<2> is H or lower alkyl) and salt thereof. EXAMPLE:7-Hydroxymethyl-3,11,15-trimethyl-2,4,6,10,14-hexadecapentaenoic acid. USE:The compound is useful as an anticancer agent, which exhibits excellent anticancer effect, has high safety and is capable of continuously using for long periods and administered orally or parenterally. PREPARATION:For example, a compound expressed by formula II is reacted with a Wittig reagent derived from formula III (X is halogen; R<3> is lower alkyl) to provide a compound expressed by formula IV in a compound expressed by formula I. The compound expressed by formula IV is then hydrolyzed to afford a compound expressed by formula V in the compound expressed by formula I. Above mentioned Wittig reagent is, for example, phosphorus compound obtained by reacting the compound expressed by formula III with triphenyl phosphine, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a polyprenyl compound having excellent medicinal effects, a pharmaceutically acceptable salt thereof, a method for producing the same, and a medicine containing the same.

Conventional technology The development of anticancer drugs is extremely difficult due to the nature of the disease, and although development is proceeding from various directions mainly in developed countries, the reality is that there is no definitive drug.

Vitamin A has been linked to vitamin A deficiency and cancer development.
It is attracting attention and research as one direction in the research and development of anticancer drugs.

1971 Ba116g is a vitamin A and its esters that are preventive against epithelial tumors in animals caused by vitamin A deficiency and chemical carcinogens.

It is recognized that it has therapeutic effects.

However, since vitamin A needs to be administered in large amounts over a long period of time to treat cancer,9 it accumulates in the body at a high level.
It has drawbacks such as hypervitaminosis A as a side effect.

Therefore, there is a need for compounds other than vitamin A that are safer and can effectively reach diseased tissues.

Purpose of the Invention In view of the above-mentioned circumstances, the inventors of the present invention have conducted extensive studies over a long period of time and have found that this is a polyprenyl compound that is different from vitamin A and has higher safety.

In addition, they discovered a compound that can effectively reach diseased tissues and completed the present invention.

Therefore, two objects of the present invention are to provide a novel polyprenyl compound and a pharmacologically acceptable salt thereof, and further to provide a medicament using a method for producing the polyprenyl compound and its pharmacologically acceptable salt. That's true.

Structure and Effects of the Invention The object compound of the present invention is a polyprenyl compound represented by the following general formula (f) or a pharmacologically acceptable salt thereof.

(In the formula, n means an integer of 1 to 3. R1 means hydrogen or a lower alkyl group, and R2 means hydrogen or a lower alkyl group.) A polyprenyl compound represented by the following.

In the above definition, the lower alkyl group found in R' and R' refers to a straight chain or branched alkyl group having 1 to 6 carbon atoms, such as methyl, ethyl, n-propyl, n-butyl, isopropyl, 1-methylpropyl to isobutylene,
tert-butyl, n-pentylated 1-ethylpropyl,
It means isoamyl, n-hexyl, etc., but the most preferred example is methyl group.

It is an ethyl group.

Examples of pharmacologically acceptable salts include sodium salts, potassium salts, and calcium salts.

Furthermore, the compound of the present invention has nine various geometric isomers, and the present invention includes any of these isomers.

In the compound CI+ of the present invention, n means an integer of 1 to 3, but the most preferable result is given when n=2.

The object compound (I) of the present invention or a pharmacologically acceptable salt thereof has an excellent anticancer effect and is highly safe, so it is useful as an anticancer agent.

Representative compounds of the present invention are as follows,
The purpose thereof is to facilitate understanding of the present invention, and it goes without saying that the present invention is not limited to these.

07-hydroxymethyl-3,11,15-)limethyl-2,4,6,10,14-hexadecapenecitrate o7-hydroxymethyl-3,11,15-)limethyl-2,4,6, 10,14-hexadecapene methyl citrate 07-hydroxymethyl-3,11,15-)limethyl-2,4,6,10,14-ethyl hexadecapentenoate 07-hydroxymethyl-3,11, 15-trimethyl-2,4,6,10,14-propyl hexadecapentaenoate o7-medoxymethyl-3.11.15-)limethyl-2,4,6,10,14-hexadecaben citrate o
7-Medoxymethyl-3.11.15-)limethyl-
2,4,6,10,14-Methyl hexadecapentaenoate o7-Medoxymethyl-3.11.15- ) Dimethyl-2,4,6,10,14-Ethyl hexadecapentaenoate 07-Hydroxymethyl-3 ,11-dimethyl-2゜4
, 6.10-dodecatetraenoic acid o7-hydroxymethyl-3,11-dimethyl-2゜4
, 6.10-Methyl dodecatetraenoate o7-hydroxymethyl-3,11-dimethyl-2゜4, 6.10-Ethyl dodecatetraenoate o7-medoxymethyl-3,1
1-dimethyl-2,4°6.10-dodecatetraenoic acid 07-medoxymethyl-3.11-dimethyl-2,4°6.10-dodecatetraenoic acid methyl 07-medoxymethyl-3,11-dimethyl-2,4゜6,10.14.18-Methyl eicosahexaenoate 6
, 10.14.18-Eicosahexaenoate 07
-Medoxymethyl-3.11.15.1♂ma 〒1゜1
Ethyl 4-hexadecapentaenoate The compound of the present invention can be produced by two different methods, specific examples of which are as follows.

Production method 1 A compound represented by general formula (II) (wherein R1 means hydrogen or a lower alkyl group, and n means an integer of 1 to 3) is added to a compound represented by general formula (III) (wherein X is a halogen atom and R3 means a lower alkyl group) is reacted with a Wittig reagent derived from a compound represented by
(n, R', and R3 have the above-mentioned meanings) 2 Next, this is hydrolyzed to obtain compound (V), which is one of the L1-like substances.

(In the formula, n and R1 have the above-mentioned meanings.) In this method, the Wittig reagent derived from the compound of general formula (II) is 2, for example, triphenylphosphine, phenyldialkoxyphosphine, tri- Examples include phosphorus compounds obtained by reacting alkyl phosphites. The preparation of this reagent and the Wittig reaction using this reagent are described in 2, for example by Gedye.
[Canadian Journal of Chemistry, Volume 55, Page 1218 (1977)].

One specific method is as follows.

Examples of catalysts for carrying out the Wittig reaction include sodium methylate (MeONa), sodium ethylate (EtONa), t-BuOK,
Examples include NaH, and examples of the solvent include tetrahydrofuran (THF) and dimethylformamide (DMF).

Ethers, nitromethane, dimethyl sulfoxide (D
MSO), etc. Further, a reaction temperature of -60°C to about 100°C gives preferable results.

Hydrolysis can also be carried out using a base commonly used for hydrolyzing carboxylic acid esters, such as sodium hydroxide or potassium hydroxide.

Compound used as a starting material in production method 1 (
IT) can be obtained by the following method, for example.

Production method 2 When RI is H in target substance (I), it is also possible to produce 2, for example, by the following method.

(XIV) (λVl) (4th step) The first hydrolysis step is a step of subjecting the aldehyde represented by compound (X'') to a Wittig reaction with compound (X III ) to obtain compound (XIV), The reaction is carried out according to the method described in Production Method 1.

In the second step, the acetal compound (XIV) is brought into contact with an acid, the acetal bond is hydrolyzed, and the formyl compound ('XV
). Examples of acids that can be used include organic acids such as formic acid and acetic acid, and mineral acids such as hydrochloric acid and sulfuric acid. This reaction is usually carried out in water or a water-containing organic solvent.

The third step is the formyl compound (X￥) obtained in the second step.
This is the process of reducing the alcohol to form the alcohol (XVI).

As the reducing agent, for example, an alkali metal hydride salt such as sodium borohydride or potassium borohydride, or aluminum triisopropoxide is used.

The fourth step is a step of hydrolyzing the ester bond of compound (XVI) obtained in the third step, and is usually 9.

For example, it can be carried out using a base used for hydrolysis of carboxylic acid esters, such as sodium hydroxide or potassium hydroxide.

In production method 2, the compound ('X1l) used as a starting material can be obtained, for example, by the following method.

Next, to explain in detail the effects of the compounds of the present invention.

Examples of pharmacological experiments are shown.

Examples of pharmacological experiments As a representative compound of the present invention, Compound A: (E.

E,Z,E)-7-Medoxymethyl-3.11.15-
Trimethyl-2,4,6,10,14-hexadecapene citric acid and compound B: (E, E, Z, E
)-7-hydroxymethyl-3,11,15-trimethyl-acid-biding protein (CR
ABP) (molecular weight approximately 14,600--...---O
ng, D., E., Chytil, F., J.
, Biol, Chem,, 253.

4551-4554 (197B) and Ross,
A., C., Adachi, N.;

Goodman, D. S., J., Lipid R.
es,, 21. The binding affinities of these compounds (see Zoo~109 (1980))
g affinity) was measured.

The results are shown in FIGS. 1 and 2.

Figures 1 and 2 show the binding affinities of Compound A and Compound B to rat CRABP, respectively.
fTinity).

The horizontal axis shows the concentration of the compound (μM), and the vertical axis shows.

bincling affinit for CRARP
Indicates y%. This binding affinity
pJ indicates a percentage when the case of retinoic acid is set as 100.

From Figure 1, 50% biding affi of compound A
The concentration showing the same property is 38 μM, and similarly that of compound B is localized in the testis, ovary, eye, trachea, and skin epidermis of animals, whereas it is localized in the epidermis of human breast cancer, lung cancer, primary liver cancer, and glioma. It has been detected at high levels in cancer and experimental tumors such as mouse skin papillomas.

Therefore, 9 compounds of the present invention were prepared as shown in the above pharmacological experiment example (C
Strong bidding affinity for RABP
(Binding affinity) means having an excellent antitumor effect and being useful as an anticancer agent.

Therefore, the two compounds of the present invention are useful as agents for preventing and treating cancer and precancerous symptoms.

Furthermore, the compound of the present invention has extremely low toxicity and can therefore be used for a long period of time, making it highly valuable as an anticancer agent.

When the compound of the present invention is administered as an anticancer agent, it may be administered orally as a powder, granule, capsule, syrup, etc., or as a suppository or injection.

It may also be administered parenterally as an external preparation or a drop.

The dosage varies considerably depending on the severity of the symptoms, age, type of cancer, etc., but it is usually about 5 #1 g to 1,50 g per day for adults.
Administer 0 my in divided doses 2 to several times a day.

When formulating the product, it is manufactured by a conventional method using a conventional pharmaceutical carrier.

That is, when preparing oral solid preparations, excipients are added to the crude drug, and if necessary, binders and disintegrants are added.

Lubricants 9 After adding coloring agents, flavoring agents, etc., the mixture is prepared into tablets, coated tablets, granules, powders, capsules, etc. by conventional methods.

Examples of excipients include lactose and cornstarch.

White sugar, glucose, sorbitol, crystalline cellulose.

Examples of binders include silicon dioxide, polyvinyl alcohol, polyvinyl ether, ethyl cellulose, methyl cellulose, gum arabic, tragacanth, gelatin, shellac, hydroxypropyl cellulose,
Hydroxypropyl starch, polyvinylpyrrolidone, etc., disintegrants include starch, agar, gelatin powder, crystalline cellulose, calcium carbonate, sodium bicarbonate, calcium citrate, dextrin, pectin, etc., lubricants include stearin, etc. Magnesium acid, talc, polyethylene glycol.

Silica, hydrogenated vegetable oil, etc.9 are permitted to be added to pharmaceuticals as coloring agents, but as flavoring agents, cocoa powder, noitsutsukano, aromatic acid, noitsutsuka oil, dennou,
Cinnamon powder etc. are used. Of course, these tablets and granules may be coated with sugar coating, gelatin coating, or other coatings as appropriate.

When preparing injections, pH adjusters, buffers, stabilizers, solubilizers, etc. are added to the main drug as necessary, and the preparations are made into subcutaneous, intramuscular, or intravenous injections using conventional methods.

Examples of the present invention are listed below, but it goes without saying that the present invention is not limited thereto.

Example 1 (E,E,Z,E)-7-methoxymethyl-3°11.
15-) Synthesis of dimethyl-2,4,6,10,14-hexaster Powdered sodium ethoxide obtained from 1.13.9 ml of sodium metal and 50 ml of ethanol was mixed with 50 ml of n-hexane.
ml, and 12.1 J of triethylphosphonoacetate is added while stirring under water cooling. After 10 minutes (E)-
Add 5.5y of 1-methoxymethyl-6,10-dimethyl-5,9-undecadien-2-one and stir for 30 minutes. The mixture is poured into water, the n-hexane layer is separated, and the n-hexane layer is washed with water and then dried over magnesium sulfate. The solvent was distilled off and separated by silica gel column chromatography.
Purification gave the title compound 3.2I.

NMR-δ (CDC13): 1.28 (3H,t,
J=7)Lz), 1.60 (6H,s).

5.75 (IH, bs) 2.9 g of ethyl (Z,E)-3-methoxymethyl-7,11-dimethyl-2,6,10-dodecatrienoate obtained by the method of (1) was added to 15++A of tetrahydrofuran.
! diisobutylaluminum hydride (1,5M toluene solution) 2Qd was added dropwise while stirring under water cooling. After dropping, stir for 1 hour and acidify by adding diluted hydrochloric acid. After extraction with ethyl ether and washing with water.

Dry with magnesium sulfate. The solvent was distilled off and the residue was purified by silica gel chromatography to obtain 2.3 g of the desired product.

Silence・δ(CDC!,): 1.61 (6H,s)
, 1.68 (3H,s).

1.9-2.23 (8H, m), 2.38 (IH
, bs), 3.38 (3H,s).

3.95 (2H, s), 4.18 (2H, d,
J=6Hz), 5.10 (2H, m).

5.58 (IH, t, J = 6 Hz) 2.0 g of (Z, E)-3-methoxymethyl-7,11-dimethyl-2,6,10-dodecatrienol obtained in (2) was dissolved in chloroform. Dissolve in 20 x L, add 5 g of activated manganese dioxide, and stir for 1 hour.

Thereafter, it is filtered through Celite and washed with chloroform. When the filtrate was distilled off, 1.9 g of the target product was obtained.

NMR-δ (CDCjs): 1.59 (6H,s
), 1.68 (3H,s).

1.8-2.6 (8H, m), 3.37 (3H,
s), 4.36 (2H, s).

5.08 (2H, m), 5.94 (IH, d,
J=7Hz).

10.07 (IH, d, J=7Hz)-' - Powdered sodium ethoxide obtained from 0.28 g of sodium metal and 10 ml of ethanol was mixed with 20.0 g of dimethylformamide. The suspension was cooled to -20°C, and 3.5 hours of diethyl-3-ethoxycarbonyl-2-methyl-2-flopenylphosphonate was added while stirring under a nitrogen atmosphere. Add 200G to this solution without stirring <, Z, E)-
3-methoxymethyl-7,11-dimethyl-2,6,1
A solution of 1.5 g of 0-dodecatrienal in 5 ml of dimethylformamide is added dropwise. After 1 hour, the reaction solution was poured into ice water.

Extract with ethyl ether, wash with water, and dry with magnesium sulfate. The solvent was distilled off and the residue was purified by silica gel column chromatography to obtain the title compound 1.4y.

NMR・δCCDC15): 1.28 (3H,t
, J=7±).

1.60 (6H, s), 1.64 (3H, s),
1.8-2.2 (8H, m).

2.32 (3H, d, J=IHz), 3.32
(3H,s), 4.60 (2H,s).

4.16 (2H, q, J=7Hz), 5.10
(2H, m), 5.76 (LH, bs).

6.10 (IH, d, J=11Hz), 6.21
(IH, d, J=15Hz).

6.94 (LH, dd, J=11.15 output) Example 2 0.4.9 of potassium hydroxide was dissolved in 1 of isopropyl alcohol
(E,E,Z,E)-7-medoxymethyl-3.11 obtained by the method of Example 1 was dissolved in QmJ and added thereto.
．． Add 1.2 I of ethyl bovine decabentaenoate to 15-trimethyl-2,4,6,10,14- and heat under reflux for 15 minutes. The reaction solution is poured into ice water, acidified by adding dilute hydrochloric acid, extracted with ethyl ether, and the extract is washed with water and dried over magnesium sulfate. Colorless oil obtained by distilling off the solvent and purifying with silica gel chromatography 0.9
When g was dissolved in 5M n-hexane and cooled to -20°C to crystallize, the title compound was 0.6! 9 was obtained as white crystals.

Melting point: 49-50'C MASS: m/z 332 (M) NMR-δ
(CDC4) 400MHz: 1.60 (3H,
s), 1.61 (3H, s).

168 (3H, s), 194~2.30 (8H,
m).

2.33 (3H, d, J=IHz), 3.34
(3H,s), 4.35 (2H,s).

5.10 (2H, m), 5.81 (LH, bs)
, 6.09 (IH, d, J=11Hz).

6.26 (LH, d, J = 15Hz), 6.
99 (LH, dd, J=11.15Hz).

7.14 (LH,s) Example 3 Powdered sodium ethoxide obtained from 0.72.9 l of sodium metal and 30 l of ethanol was mixed with 4 l of n-hexane.
Suspend in Q me and add 7.8 I of triethylphosphonoacetate while stirring under water cooling. After 10 minutes (El
-1゜1-dimethoxymethyl-6,10-dimethyl-5
,9-undecadien-2-one 4.0 ml was added, 30
Stir for a minute. The mixture is poured into water to separate the n-hexane layer, which is washed with water and then dried over magnesium sulfate. The solvent was distilled off, and the residue was separated and purified by silica gel chromatography to obtain 1.9 g of the title compound.

NM, R・δ (CDCl, ): 1.28 (3H,
t, J=full), 1.60 (6H, s).

1.68 (3H, s), 1.8~2.4 (8H,
m), 3.41 (6H, s).

4.16 (2H, q, J=7Hz), 5.10
(2H, m), 5.80 (IH, s).

5.96 (IH,s) Combination of dimethyl-2,6,10-dodecatrienol (Z,E)-3-dimethoxymethyl-7,11-dimethyl-2,6,10-dodecatrienoic acid Dissolve 1.77% of ethyl in 7 liters of tetrahydrochloride under water cooling.

Diisobutylaluminum hydride (1,5
Add 10 d of M l-luene solution) dropwise. After dropping, stir for 1 hour and acidify by adding dilute hydrochloric acid. Extract with ethyl ether, wash with water, and dry over magnesium sulfate. The solvent was distilled off and the residue was purified by silica gel chromatography to obtain 1.3 g of the title compound.

NMR・δ(CDC4): 1.60 (6H,s)
, 1.68 (3H,s).

1.8-2.2 (8H, m), 2.45 (LH,
b), 3.32 (6H,s).

4.24 (2H, d, J=6Hz), 4.95
(LH,s), 5.12 (2H,m).

5.70 (LH, t, , J=6Hz) (Z, E) -
3-dimethoxymethyl-7,11-dimethyl-2,6,
10-dodecatrienol 1.2I in chloroform 1Q
ml, add 3g of activated manganese dioxide to this and add 1
Stir for an hour. Thereafter, it is filtered through Celite and washed with chloroform. When liquid F was distilled off, the title compound 1. I got IJ.

NMR1Iδ (CDCl, ): 1.60 (6H, s
), 1.67 (3H, s).

1.8-2.4 (8B, m), 3.36 (6H
,s), 5.08 (2H,m).

5.32 (IH, s), 5.95 (IH, d,
J=7Hz).

IQ, 18 (LH, d, J = 7 Hz) Powdered sodium ethoxide obtained from 0.16 F of metallic sodium and 10 rnl of ethanol was mixed with 1QmA of dimethylformamide.
Suspended in
2-propenylphosphoney 1-2,IJ was added. Add (Z,E)-3-dimethoxymethyl-7,11-dimethyl-2,6,10- to this solution at -20°C while stirring.
Dodecatrienal 1.0I dimethylformamide 5
Add mt solution dropwise. After 1 hour, the reaction mixture was poured into ice water, extracted with ethyl ether, washed with water, and dried over magnesium sulfate. The solvent was distilled off and the residue was purified by silica gel column chromatography to obtain the title compound 0.89.5+.

NhiR-δ (CDC4): 1.28 (3H,t
, J=7Hz), 1.60 (6H, s).

1.68 (3H, s), 1.9~2.2 (8H,
m), 2.32 (3H, s).

3.34 (6H, s), 4.16 (2H, q,
J=7Hz), 5.10 (3H, bs).

5.78 (LH, s), 6.14 (LH, d,
J=11Hz).

6.20 (LH, d, J=15Hz), 7.11
(LH, dd, J=11.15Hz) (E, E, Z
,E)-7-Simethoxymethyl-3゜11,15-trimethyl-2,4,6,10,14-hexadecapene citrate ethyl 0.80 g was dissolved in Q ml of acetone] and dissolved in this. Add 1rnl of water. While cooling with water and stirring, add 0.3 ml of 2N hydrochloric acid. After 1 hour, the mixture was poured into ice water, extracted with n-hexane, washed with water, and dried over magnesium sulfate. The solvent was distilled off and the residue was purified by silica gel column chromatography to obtain 0.59 jq of the title compound.

NMR・δ(CDC4): 1.29(3H,t,
J=7Hz), 1.58 (6H, s).

lL, 67 (3H, s le 1.8-2.2 (8H, m
), 2.35 (3H, d, J=1)fz).

4.20 (2H, q, J=7Hz), 5.10
(2H, m), 5.90 (LH, bs).

6.28 (IH, d, J=15±), 6.90
(IH, d, J=11±).

7.52 (IH, d, J=11.15Hz), 1
0.28 (IH,s)(E,E,Z,E)-7-formyl-3,11,15-trimethyl-2,4,6,1
Ethyl 0,14-hexadecapentaenoate 0.55 I
Dissolve / in 5 ml of ethanol.

Under water cooling, add sodium borohydride (30 m9) and stir for 1 hour. After the reaction is complete, add dilute hydrochloric acid to acidify, add water and extract with ethyl ether. After washing with water, dry over magnesium sulfate. Remove the solvent by distillation. The residue was purified by silica gel column chromatography to obtain 0.48 g of the title compound.

NMR-δ (CDC4): 1.27 (3H,t,
J=7I-Iz), 1.60 (6H,s).

1.68 (3H, s), 1.9~2.3 (9H,
m), 2.30 (3H, d, J4Hz).

4.16 (2H, q, J=7)Lz), 4.28
(2H, s), 5.10 (2H, m).

5.76 (LH, s), 6.06 (IH, d,
J=111(z).

6.21 (LH, d, J=16Hz), 6.94
(IH, dd, J=11.16Hz) Example 4 0.13 g of potassium hydroxide was mixed with 50 g of isopropyl alcohol.
ml of (E,E,Z,E)-7-hydroxymethyl-3,11,15-)limethyl-2,4
゜6,10.14-Ethyl hexadecapentaenoate 0.
Add 40 g and heat under reflux for 15 minutes. The reaction solution is poured into ice water, acidified by adding diluted hydrochloric acid, extracted with ethyl ether, and the extract is washed with water and dried over magnesium sulfate. The white crystals obtained by distilling off the solvent and purifying with silica gel chromatography are dissolved in a mixture of 2 ml of n-hexane, ethanol Q, and 3 zl, and recrystallized by cooling to -20°C to obtain the title compound. .25& was obtained as white crystals.

, Melting point: 54-55°C MASS: m/z 318 (M)NMR-
δ(CDC4,) 400 MHz: 1.60 (
3H,s).

1.61 (3H,s), 1.68 (3H,s),
1.9-2.3 (8H, m).

2.33 (3H, d, J=IHz), 2.80
(IH, b), 4.35 (2H, s).

5.08 (LH, t, J=6Hz), 5.13
(LH, t, J=7Hz).

5.81 (IH, s), 6.08 (IH, d,
J=11Hz).

6.26 (LH, d, J=15Hz), 6.99
(IH, dd, J=11.15Hz).

7.26 (IH,s)

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows the binding affinity of Compound A to CRARP. FIG. 2 shows the binding affinity of Compound B to (RA) CRABP.

Claims (3)

[Claims] (1) Represented by the general formula (in the formula, n means an integer of 1 to 3; R^1 means hydrogen or a lower alkyl group; R^2 means hydrogen or a lower alkyl group) Polyprenyl compounds and their pharmacologically acceptable salts. (2) The polyprenyl compound according to claim 1, where n=2, and a pharmacologically acceptable salt thereof. (3) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, n means an integer from 1 to 3. R^1 means hydrogen or a lower alkyl group, R^2 means hydrogen or An anticancer agent containing a polyprenyl compound represented by (meaning a lower alkyl group) or a pharmacologically acceptable salt thereof as an active ingredient.