NOVEL 6-SUBSTITUTED-5,8-DIOXY-l,4-NAPHTHOQUINONE DERIVATIVES

TECHNICAL FIELD

The present invention relates to a novel 6-substituted -5, 8-dioxy-l, 4-naphthoquinone derivative represented by the following formula (I) , which has a potent anti-cancer 10 activity:

20 in which

R- _j _ represents alkyl;

R represents hydrogen, alkyl or acyl; and

R ₃ represents hydrogen or alkyl .

25 The present invention also relates to a process for pre¬ paring the naphthoquinone derivative of formula ( I ) , as def ined above , and use of the compound ( I ) as an anti - cancer agent .

30 BACKGROUND ART

The study to find a suitable method for treatment of cancer which is one of current typical incurable diseases 35 has been actively conducted by means of chemotherapy, physical therapy and genetic engineering technique to¬ gether with the study of attacking and progressing mecha-

nis of cancer. In the chemotherapy as one of various treatment methods as mentioned above, it has been attempt¬ ed to treat cancer using an anti-cancer agent. However, anti-cancer agent which can effectively treat cancer is very few as yet. Accordingly, many attempt to develop drugs having new acting mechaninsm and high anti-cancer activity has been continuously made. Such attempt to develop the anti-cancer agent has been conducted to find substances having anti-cancer activity from medicinal herbs as well as in the field of pure organic synthesis and further extended to syntheis of analogous compounds having anti-cancer activity by transformation of the components separated from the natural material according to the organic synthetic method.

As one of the result of such study, shikonin repre¬ sented by the following formula (A) [=2- (1-hydroxy-4- methyl-3-pentenyl) -5, 8-dihydroxy-l, 4-naphthoquinone] has been developed:

Shikonin was first isolated from Alkana tinctoria by H. Brockmann in 1936 [Ann. Chem. 521, 1-47(1936)] and then from various plants belonging to Borraginaceae, and has been known as a compound having anti-cancer activity. However, shikonin itself has a potent cytotoxicity against cancer cells in vitro but shows a very weak anti-cancer activity in animal body. It is anticipated that such weak activity in animal body is caused by the fact that the metabolic rate of shikonin in the animal body is

faster than the onset of its activity. It has been assumed that in living body shikonin is metabolized through the following three pathways. The first is an oxidation mechanism because phenolic hydroxy group and a double bond on 3 ' carbon atom in the structure of shikonin is susceptible to oxidation. The second is a reduction mechanism in which a quinone structure is reduced to a semiquinone or hydroquinone form by receiving an electron¬ ic pair or electronic radical thereby shikonin loses its pharmacological activity. The third is a phase II metab¬ olism of hydroxy group on 1" carbon atom of shikonin. During this phase II metabolic pathway, the hydroxy group is rapidly excreted in the form of glucuronide or sulfate to cause the shortening of duration of pahrmacological effect. Thus, it has been considered that shikonin exhibits a weakened anti-cancer activity in the living body due to the above-mentioned three causes.

In order to make up for such disadvantages of shikonin as mentioned above to develope an anti-cancer compound having more potent pharmacological activity, many studies have been made to prepare a certain compound having a structure which is stable in the living animal body, by introducing various substituents into the structure of shikonin (A) . Such studies have been mainly conducted to design a compound having the structure which is safely delivered to the target focus after administration to human being, and then can be converted into an active substance analogous to shikonin (A) . As a result of such study, the present inventors identified that a certain compound of formula (I) , as defined above, is an ideal compound which can achieve such purpose. Then, now we have completed the present invention.

DISCLOSURE OF INVENTION

Thus, it is an object of the present invention to pro¬ vide a 6-substituted-5, 8-dioxy-1,4-naphthoquinone deriva¬ tive having the following formula (I) :

in which

R- _j _ represents alkyl;

R ₂ represents hydrogen, alkyl or acyl; and R ₃ represents hydrogen or alkyl .

It is another object of the present invention to provide a process for preparing a 6-substituted-5, 8-dioxy- 1, 4-naphthoquinone derivative having the following formula (I) :

in which

R- _| _ represents alkyl; R ₂ represents hydrogen, alkyl or acyl; and

R, represents hydrogen or alkyl, characterized in that

(A) a naphthalene derivetive having the following formula (II) :

wherein R-^ and R3 are defined as above, is debenzylat- ed to obtain a compound having the following formula (III ¹ ) :

wherein R-, and R, are defined as above, which is oxidized to prepare a compound having the following formula (la) :

wherein R-_ and R3 are defined as above;

(B) a compound having the following formula (la)

wherein R-_ and R ₃ are defined as above, is reacted with an acylating agent to prepare a compound having the following formula (lb) :

wherein R _η and R3 are defined as above and R _2a repre¬ sents acyl;

(C) a naphthalene derivative having the following formula (III) :

wherein R^ and R3 are defined as above, is reacted with an alkylating agent to obtain a compound having the following formula (IV) .*

wherein R-_ and R ₃ are defined as above and R _2£ repre¬ sents alkyl, which is oxidized to prepare a compound having the following formula (Ic) :

wherein R^_ , R _2] _. and R ₃ are defined as above.

It is still another object of the present invention to provide an anti-cancer agent comprising as an active ingredient a 6-substituted-5, 8-dioxy-l , 4-naphthoquinone derivative of formula (I) , as defined above, together with a pharmaceutically acceptable carrier.

BEST MODE FOR CARRYING OUT THE INVENTION

Thus, the present invention relates to a 6-substitut- ed-5,8 -dioxy-1 , 4-naphthoquinone derivative having the following formula (I) :

in which R- _j _ represents alkyl;

R ₂ represents hydrogen, alkyl or acyl; and R ₃ represents hydrogen or alkyl .

In the definitions of substituents in the formula (I) , the term "alkyl" denotes a straight or branched, saturated hydrocarbon radical, particularly those having 1 to 12 carbon atoms, such as methyl, ethyl, n- or isopropyl, n- , iso-, sec- or tert-butyl, pentyl , isopentyl, hexyl, hep- tyl , octyl, nonyl , decyl, dodecyl , etc.; and the term "acyl" includes a group derived from saturated or unsatu- rated aliphatic hydrocarbons, for example, alkanoyl having 1 to 20 carbon atoms, particularly 1 to 10 carbon atoms, such as formyl, acetyl , propanoyl , butanoyl, hexanoyl , heptanoyl, octanoyl, nonanoyl , etc. , or alkenoyl having one double bond and 2 to 20 carbon atoms, particularly 2 to 10 carbon atoms, such as acryloyl, methacryloyl, cro- tonoyl, pentenoyl, hexenoyl, etc.

As can be seen from the following reaction scheme 1, the compound of formula (I) is subjected to dealkylation, tautomerism and the like in the living body to cause the reduction of biological metabolic rate. According to this, the concentration of the compound (I) delivered to the target cancer cells is increased, and ultimately, the compound of formula (I) can exhibit an increased anti- cancer activity. That is, for example, when in the compound of formula (I) R-_ is isopentyl, R ₂ is hydrogen

and R3 is methyl, the compound 6 - ( 1 -hydroxy-4 - methylpentyl) -5 , 8-dimethoxy-l , 4-naphthoquinone (I ¹ ) is demethylated by a phase I metabolic pathway which is essential in the course of metabolism of alkoxyphenol in the living body, to form 2- (l-hydroxy-4-methylpentyl) -5, 8- dihydroxy-1, 4-naphthoquinone (B) which corresponds to a dihydroshikonin wherein the double bond of shikonon (A) is saturated. Through such procedure, the metabolic rate of the pharmacologically active compound (I) is reduced, thereby the concentration of the drug delivered to the target cancer cells is increased to cause ultimately an increased anti-cancer activity.

Reaction Scheme 1

(B)

r _Rl = CH3-CH-CH-CH-

CH,

In view of pharmacological activity, the compound of romula (I) wherein R-_ is C-^Cς alkyl, R ₂ is hydrogen, C ₁ - C ₅ alkyl or C ₂ -C _1Q alkanoyl and R ₃ is ₁ -C ₃ alkyl is preferable. The compound (I) wherein R-_ is isopentyl, R ₂ is C. _j _-C ₅ alkyl or C ₂ -C- alkanoyl and R ₃ is methyl is particularly preferable.

The present invention also relates to a process for preparing the novel 6-substituted-5, 8-dioxy-l,4-naphtho- quinone derivative of formula (I) . According to the present invention, the naphthoquinone derivative of formu¬ la (I) can be prepared according to any one of the follow¬ ing methods A, B and C.

Method A

(») (111')

(la)

Method B

Method C

oxidation

In the above reaction scheme, R^ represents alkyl; R _2a represents acyl; R ₂ k represents alkyl; R ₃ represents hydrogen or alkyl; and Bz denotes benzyl group.

Hereinafter, the process for preparation of the com¬ pound of formula (I) according to the present invention is more specifically explained.

Method A :

According to the method A, the compound of formula (I) wherein R ₂ is hydrogen (H) , i.e. the compound of formula

(la) can be prepared by debenzylating the naphthalene derivative of formula (II) to obtain the compound of formula (III ¹ ) which is then oxidized.

The first reaction step of the method A for preparing the compound (III ¹ ) from the compound (II) is a debenzyla- tion reaction according to the known catalytic reduction method. As the hydrogenation catalyst which can be used for this purpose, a metal catalyst, for example, platinum catalyst (for example, platinum plate, spongy platinum, platinum black, colloidal platinum, platinum oxide, plati¬ num wire, etc.) , nickel catalyst (for example, reduced nickel, nickel oxide, Raney nickel, etc.) , palladium catalyst (for example, spongy palladium, palladium black, colloidal palladium, palladium oxide, palladium on carbon, palladium hydroxide on carbon, palladium on barium sul- fate, palladium on barium carbonate, etc.) and the like is included, with palladium catalyst being most preferable. The reaction can be preferably carried out in the presence of a solvent. As the solvent for this purpose, ether solvent, for example, tetrahydrofuran, diethyl ether,

acetonitrile, etc. , can be used, with tetrahydrofuran being most preferable.

The reaction is preferably conducted under atmospheric pressure for 10 to 24 hours.

In the second reaction step, the resulting compound (III ' ) , 2- (1-hydroxyalkyl) -1,4-dialkoxy-5, 8-dihydroxynaph- thalene, obtained from the first reaction step is oxidized to prepare the desired compound of formula (la) wherein R ₂ is hydrogen. Since the compound of formula (III') pro¬ duced in the first reaction step is unstable, it is pref¬ erable to subject the compound (III') to the second reac¬ tion step immediately after it is prepared. The second reaction step can be advantageously carried out in the manner that the compound (III') produced in the first reaction step is not isolated and the reaction solution is filtered and can be directly used in the subsequent reac¬ tion step. However, if necessary, the second reaction step can also be conducted in a solvent different from those used in the first reaction step.

As the oxidant which can be used in the second reac¬ tion step, Pb0 ₂ , Mn0 ₂ , lead tetraacetate, cerium ammonium nitrate (CAN) , etc. , can be mentioned. Particularly, lead tetraacetate and cerium ammonium nitrate can be most preferably used. The oxidant is used in the ratio of 1 to 5 moles, preferably 1 to 1.5 moles, with respect to one mole of the starting material of formula (II) .

The compound of formula (I) wherein R ₂ is H, i.e. the compound of formula (la) , obtained according to the above method can be purified by a conventional method, for example, recrystallization, distillation, chromatography, etc.

Typical example of the compound of formula (I) wherein

R ₂ is hydrogen, which can be synthesized according to the method A includes the following compounds:

6- (1-hydrox ethyl) -5, 8-dimethoxy-1,4-naphthoquinone; 6- (1-hydroxypropyl) -5, 8-dimethoxy-1, 4-naphthoquinone; 6- (1-hydroxybutyl) -5, 8-dimethoxy-1,4-naphthoquinone,* 6- (1-hydroxypentyl) -5, 8-dimethoxy-1, 4-naphthoquinone; 6- (l-hydroxy- -methylpentyl) -5, 8-dimethoxy-1,4-naphthoqui¬ none; 6- (1-hydroxy-sec-pentyl) -5, 8-dimethoxy-1,4-naphthoquinone; 6- (1-hydroxyhexyl) -5, 8-dimethoxy-1,4-naphthoquinone,* 6- (1-hydroxy-5-methylhexyl) -5, 8-dimethoxy-1,4-naphthoqui¬ none,* 6- (1-hydroxyheptyl) -5, 8-dimethoxy-1,4-naphthoquinone; 6- (1-hydroxyoctyl) -5, 8-dimethoxy-1, 4-naphthoquinone; 6- (1-hydroxynonyl) -5, 8-dimethoxy-1,4-naphthoquinone; 6- (1-hydroxydecyl) -5, 8-dimethoxy-1, 4-naphthoquinone; 6- (1-hydroxyundecyl) -5, 8-dimethoxy-1,4-naphthoquinone; and 6- (1-hydroxytridecyl) -5, 8-dimethoxy-1,4-naphthoquinone.

Method B :

According to the method B, the compound of formula (I) wherein R ₂ is hydrogen, i.e. the compound of formula (la) , which can be produced according to the method A, is react¬ ed with an acylating agent to prepare the compound of formula (I) wherein R ₂ is acyl, i.e. the compound of formula (lb) .

As the acylating agent in the method B, any conven¬ tional acylating agent which can provide the desired acyl group in the compound of formula (lb) can be used. Preferably, an organic acid or a salt or reactive deriva- tive thereof, for example, acid halide, acid anhydride, etc., can be used as acylating agent.

The acylation reaction of the method B can be general¬ ly carried out in a solvent which does not adversely affect the reaction. The preferable solvent which can be used for this purpose includes haloalkane solvent, benzene solvent, nitrile solvent, ether solvent, for example, dichloromethane, dichloroethane, acetone, dioxane, aceto- nitrile, chloroform, hexamethylphosphoramide, tetrahydrof¬ uran, ethyl acetate, dimethylsulfoxide, N,N-dimethylforma¬ mide, pyridine, etc., or a mixture thereof. Among these solvent, a haloalkane solvent such as dichloromethane can be particularly preferable. In this reaction, it is preferable to use the solvent in an anhydrous form.

In addition, the acylation reaction can be preferably conducted in the presence of a conventional condensing agent. As typical example of the condensing agent suit¬ able for this purpose, a carbodiimide compound such as N,N' -diethylcarbodiimide, N,N' -diisopropylcarbodiimide, N,N' -dicyclohexylcarbodiimde, N-cyclohexyl-N' -morpholino- ethylcarbodiimide, etc. can be mentioned. The condensing agent which can be most preferably used in the method B according to the present invention is N,N' -dicyclohexyl- carbodiimide. In addition, this reaction may be prac¬ ticed in the presence of an inorganic or organic base. Preferable example of the inorganic or organic base which can be used includes alkali metal bicarbonate such as sodium bicarbonate, potassium bicarbonate, etc., alkali metal or alkali earth metal carbonate such as sodium carbonate, potassium carbonate, magnesium carbonate, calcium carbonate, etc., trialkylamine such as trimethyla- mine, triethylamine, N,N-diisopropyl-N-ethylamine, etc., pyridine compound such as pyridine, picoline, 4- dimethylaminopyridine, etc., and the like. Pyridine compound such as 4-dimethylaminopyridine can be most preferably used as the base.

The reaction temperature of the acylation reaction

according to method B can be varied within a wide range and the reaction is generally carried out under cooling to warming.

The compound of formula (I) wherein R ₂ is acyl, i.e. the compound of formula (lb) , obtained according to the above method B can be purified by a conventional method, for example, recrystallization, distillation, chromatogra¬ phy, etc.

Typical example of the compound of formula (I) wherein R ₂ is acyl, which can be synthesized according to the method B includes the following compounds :

6- (1-acetyloxyethyl) -5, 8-dimethoxy-l, -naphthoquinone;

6- (1-propanoyloxyethyl) -5, 8-dimethoxy-l, -naphthoquinone; 6- (1-butanoyloxyethyl) -5, 8-dimethoxy-l, 4-naphthoquinone; 6- (1-hexanoyloxyethyl) -5, 8-dimethoxy-l, 4-naphthoquinone; 6- (1-heptanoyloxyethyl) -5, 8-dimethoxy-l,4-naphthoquinone; 6- (1-acetyloxypropyl) -5, 8-dimethoxy-l, 4-naphthoquinone;

6- (1-propanoyloxypropyl) -5, 8-dimethoxy-l, 4-naphthoquinone; 6- (1-butanoyloxypropyl) -5, 8-dimethoxy-l,4-naphthoquinone; 6- (1-hexanoyloxypropyl) -5, 8-dimethoxy-l, 4-naphthoquinone; 6- (1-heptanoyloxypropyl) -5, 8-dimethoxy-l, 4-naphthoquinone; 6- (1-acetyloxypentyl) -5, 8-dimethoxy-l, 4-naphthoquinone;

6- (1-propanoyloxypentyl) -5, 8-dimethoxy-l,4-naphthoquinone,* 6- (1-butanoyloxypentyl) -5, 8-dimethoxy-l, 4-naphthoquinone; 6- (1-hexanoyloxypentyl) -5, 8-dimethoxy-l, 4-naphthoquinone; 6- (1-heptanoyloxypentyl) -5, 8-dimethoxy-l,4-naphthoquinone; 6- (l-acetyloxy-4-methylpentyl) -5, 8-dimethoxy-l,4-naphtho¬ quinone,*

6- (l-propanoyloxy-4-methylpentyl) -5, 8-dimethoxy-l, 4-naph¬ thoquinone; 6- (1-butanoyloxy-4-methylpentyl) -5, 8-dimethoxy-l, 4-naph- thoquinone; 6- (l-hexanoyloxy-4-methylpentyl) -5, 8-dimethoxy-l, -naph¬ thoquinone;

6- [1- (trans-1-pentenoyloxy) -4-methylpentyl] -5, 8-dimethoxy- 1,4-naphthoquinone;

6- [1- (trans-2-hexenoyloxy) - -methylpentyl] -5, 8-dimethoxy- 1,4-naphthoquinone; 6- (l-octanoyloxy-4-methylpentyl) -5, 8-dimethoxy-l, 4-naph¬ thoquinone; and

6- (l-decanoyloxy-4-methylpentyl) -5, 8-dimethoxy-l, 4-naph¬ thoquinone.

Method C :

According to the method C of the present invention, the naphthalene derivative of formula (III) is reacted with an alkylating agent to obtain the compound of formula (IV) which is then oxidized to prepare the compound of formula (I) wherein R ₂ is alkyl, i.e. the compound of formula (Ic) .

In the first reaction step of the method C, the naph¬ thalene derivative of formula (III) is alkylated to obtain the compound of formula (IV) . As the alkylating agent in this reaction, any alkylating agent which can introduce the desired alkyl group into R in the compound of formula (I) can be used and a haloalkane such as iodoalkane, bromoalkane or chloroalkane is generally used. The alkylating agent is used generally in the ratio of 1 to 5 moles, preferably 1 to 2 moles, with respect to one mole of the compound of formula (III) .

The alkylation reaction of the first reaction step can be preferably carried out in the presence of a base. As the base which can be used for this purpose, an inorganic base, for example, alkali metal hydride such as sodium hydride, potassium hydride, etc., alkali metal amide such as sodium amide, potassium amide, etc. can be mentioned.

The reaction temperature for carrying out this reac¬ tion can be varied within a wide range and the reaction is generally conducted at room temperature to elevated tem¬ perature.

In the second reaction step, the compound of formula

(IV) obtained in the first reaction step is oxidized to prepare the desired compound of formula (Ic) . As the oxidant which can be used in the second reaction step, Pb0 ₂ , Mn0 ₂ , lead tetraacetate, cerium ammonium nitrate (CAN) , etc., can be mentioned. Particularly, lead tetr¬ aacetate and cerium ammonium nitrate can be most prefera¬ bly used. The oxidant is used in the ratio of 1 to 5 moles, preferably 1 to 1.5 moles, with respect to one mole of the compound of formula (IV) .

The compound of formula (I) wherein R ₂ is alkyl, i.e. the compound of formula (Ic) , obtained according to the above method can be purified by a conventional method, for example, recrystallization, distillation, chromatography, etc.

Typical example of the compound of formula (I) wherein R is alkyl, which can be synthesized according to the method C includes the following compounds:

6- (1-methoxy-4-methylpentyl) -5, 8-dimethoxy-l, 4-naphthoqui¬ none; 6- (l-ethoxy-4-methylpentyl) -5, 8-dimethoxy-l,4-naphthoqui- none,*

6- (1-isopentyloxy-4-methylpentyl) -5, 8-dimethoxy-l,4-naph¬ thoquinone;

6- (l-pentyloxy-4-methylpentyl) -5, 8-dimethoxy-l, 4-naphtho¬ quinone; 6- (l-heptyloxy-4-methylpentyl) -5, 8-dimethoxy-l,4-naphtho¬ quinone; and 6- (l-dodecyloxy-4-methylpentyl) -5, 8-dimethoxy-l, 4-naphtho-

quinone .

The compound of formula ( I ) according to the present invention exhibits a potent anti-cancer activity . Par- ticularly, as can be seen from the test examples described below, the compound of formula (I ) shows a potent cytotox¬ icity against cancer cell s such as L1210 , K562 , A549 cells , etc . , and also exhibits a remarkable life lengthen¬ ing effect in mouse suffering from S-180 sarcoma .

Accordingly, it is another object of the present invention to provide an anti-cancer agent comprising the compound of formula (I) as an active ingredient, together with a pharmaceutically acceptable carrier.

The composition of the present invention can be formu¬ lated according to a conventional pharmaceutical method in the form of orally administrable preparation such as tablet, capsule, troche, solution, suspension, etc. , injectable preparation such as injectable solution or suspension, or ready-to-use injectable dry powder which can be reconstituted with distilled water for injection just before it is used, topical preparation such as oint¬ ment, cream, solution, etc., and the like preparation.

The carrier which can be used in the composition of the present invention includes those conventionally used in the pharmaceutical field, for example, binder, lubri¬ cant, disintegrating agent, excipient, solubilizer, dis- persing agent, stabilizing agent, suspending agent, color¬ ing agent, flavouring agent, etc., in the case of oral preparations; preservative, agent for painlessness, solu- bilizing agent, stabilizing agent, etc., in the case of injectable preparations; base, excipient, lubricant, preservative, etc., in the case of topical preparations, etc. The pharmaceutical preparation thus prepared can be administered via oral route or parenteral route, for exam-

pie, intravenous, subcutaneous or intraperitoneal injec¬ tion, or can be topically applied. In addition, in order to prevent decomposition of the drug with gastric acid when it is administered per orally, it may be preferable to administer the pharmaceutical preparation together with an antacid or to formulate the oral solid preparation such as tablet into an enteric-coated preparation.

Although a suitable dosage of the compound of formula (I) according to the present invention for human being can be appropriately determined depending on various factors including absorption, inactivation and excretion rate of the active compound in the living body, age, sex and condition of the subject patient, kind and severity of cancer to be treated, and the like, the compound of formu¬ la (I) can be administered generally in an amount of 10 to 600mg per day, preferably 50 to 400mg per day, for adult human being. However, it should be understood that the dosage to be administered can be appropriately reduced or increased depending on individual requirement and decision of physicians based on condition of individual patient and complications by means of a specialized manner. The daily dosage of the active compound can be administered once a day or in multiply divided amount preferably over 2 to 4 times.

The present invention will be more specifically illus¬ trated in the following examples and test examples. However, it should be understood that the present inven- tion is not limited to those examples in any manner. In the examples, the solvent used for NMR is CDCI3 in case of ¹ H-NMR and CHCI3 in case of ¹³ C-NMR.

EXAMPLE 1

Synthesis of 6- (1-hvdroxyethyl) -5 , 8-dimethoxy-l,4-naphtho¬ quinone

lg(2.05 mmole) of 2- (1-hydroxyethyl) -1, 4-dimethoxy- 5, 8-dibenzyloxynaphthalene was dissolved in 20ml of anhy¬ drous tetrahydrofuran and then hydrogenated under atmos- pheric pressure for 24 hours by adding 0.05g of 5%-Pd/C thereto. The reaction mixture was filtered and concen¬ trated under reduced pressure. The residue was immedi¬ ately dissolved in 20ml of acetonitrile and then 1.12g(2.05 mmole) of cerium ammonium nitrate (CAN) was added thereto and the mixture was stirred for 10 minutes. The reaction mixture was stirred with addition of 200ml of distilled water and then extracted twice with 200ml of dichloromethane. To the extract was added lOg of anhy¬ drous sodium sulfate, and the mixture was stirred and then filtered. The filtrate was concentrated under reduced pressure to obtain the reddish-brown reaction product. The resulting product was dissolved in 5ml of hexane:ethyl acetate (2:1) and then subjected to silica gel column chromatography (column size: 1.5X15cm) using the same solvent system as eluant . The fractions of reddish- purple band were collected and then concentrated to obtain 490mg of the title compound as a red oil.

Yield : 75.6% Rf : 0.53 (silica gel thin layer film, hexane:ethyl acetate=l:2) - ^■ -H-NMR (ppm, δ) :

7.55(s. IH) , 6.78(s, 2H) , 5.31(q, J=18.8Hz, IH) , 3.99(s, 3H) , 3.84(s, 3H) , 2.31(br s, IH) , 1.53(d, J=6.6Hz)

IR (cm ^-1 ) : 3475, 2950, 1650, 1460

EXAMPLE 2 Synthesis of 6- (1-hydroxypropyl) -5 , 8-dimethoxy-l , 4-naph¬ thoquinone

2- (1-Hydroxypropyl) -1,4-dimethoxy-5, 8-dibenzyloxynaph- thalene was used as the starting material and treated according to the same procedure as Example 1 to obtain 460mg of the title compound.

Rf : 0.55 (silica gel thin layer film, hexane:ethyl acetate=l:2) - ^■• H-NMR (ppm, δ) :

7.50(s, IH) , 6.78(S, 2H) , 5.05(m, IH) , 3.99(s, 3H) , 3.83(s, 3H) , 2.24(br s, IH) , 1.86-1.71 (m, 2H) , 1.02(t, J=14.8Hz, 3H) IR (cm ^-1 ) : 3475, 2950, 1650, 1460

Example 3

Synthesis of 6- (l-hydroxybutyl) -5 , 8-dimethoxy-l , 4-naph¬ thoquinone

2- (1-Hydroxybutyl) -1 , 4-dimethoxy-5 , 8-dibenzyloxynapht- halene was used as the starting material and treated according to the same procedure as Example 1 to obtain 450mg of the title compound.

Yield : 73.1% Rf : 0.15 (silica gel thin layer film, hexane: ethyl acetate=2 : 1) - ^* Η-NMR (ppm, δ) :

7.54(S, IH) , 6.75(s, 2H) , 5.15 (m, IH) , 3.97(s, 3H) , 3.80(S, 3H) , 3.19(d, J=3.45Hz, IH) , 1.74-1.26 (m, 4H) , 0.96(t, J=13.6Hz, 3H)

IR (cm ^-1 ) : 3470, 2950, 1645, 1450

Example 4 Synthesis of 6- (1-hydroxypentyl) -5 , 8-dimethoxy-l ,4-naphth¬ oquinone

2- (1-Hydroxypentyl) -1, 4-dimethoxy-5, 8-dibenzyloxynaph- thalene was used as the starting material and treated according to the same procedure as Example 1 to obtain the title compound.

Yield : 78.9%

Rf : 0.59 (silica gel thin layer film, hexane:ethyl acetate=l:2) ¹ H-NMR (ppm, δ) : 7.51(8, IH) , 6.78(s, 2H) , 5.15 (m, IH) , 3.99(s, 3H) , 3.83(s, 3H) , 2.25(br s, IH) , 1.79-1.20 (m, 6H) , 0.92(t, J=6.0Hz, 3H) IR (cm ^-1 ) : 3475, 2950, 1650, 1460

Example 5

Synthesis of 6- (l-hydroxy-4-methylpentyl) -5 , 8-dimethoxy-

1 , 4-naphthoquinone

2- (1-Hydroxy-4-methylpentyl) -1,4-dimethoxy-5, 8-diben- zyloxynaphthalene was used as the starting material and treated according to the same procedure as Example 1 to obtain the title compound as a reddish-purple oil.

Yield : 78%

Rf : 0.41 (silica gel thin layer film, hexane:ethyl acetate=l:2) ---H-NMR (ppm, δ) :

7.51(s, IH) , 6.74(s, 2H) , 5.09 (m, IH) , 3.96(s, 6H) , 3.80(s, 3H) , 2.91(br s, IH) , 1.80-1.15 ( , 5H) , 0.88(d, J=6.1Hz, 6H) IR (cm ^-1 ) : 3475, 2950, 1650, 1460

Example 6

Synthesis of 6 - ( 1 -hydroxyhexyl ) - 5 , 8 -dimethoxy- l , 4 -naph¬ thoquinone

0.336g(14.01 mmole) of magnesium and 1.33ml (14.01 mmole) of 1-bromoheptane were added to 30ml of anhydrous tetrahydrofuran and then stirred for 2 hours at room temperature to prepare Grignard reagent . To this reagent was added dropwise a solution of 2g(4.7 mmole) of 1,4- dimethoxy-3-formyl-5, 8-dibenzyloxynaphthalene dissolved in anhydrous tetrahydrofuran over 20 minutes, and the mixture was stirred for further 3 hours at room temperature. After adding 80ml of 10% ammonium chloride, the reaction mixture was extracted with dichloromethane. The extract was dried over anhydrous sodium sulfate and concentrated under reduced pressure to obtain the crude product which was then subjected to silica gel column chromatography

(column size : 1.5X15cm) using n-hexane:ethyl acetate (3:1) mixed solvent as eluant to obtain 1.9g of the title com¬ pound as a pale yellow oil .

Yield : 85%

Rf : 0.48 (silica gel thin layer film, n-hexane:ethyl acetate=3:l)

¹ H-NMR (ppm, δ) :

7.37-7.70(m, 10H) , 6.97(s, IH) , 6.93(s, 2H) , 5.14(s, 2H) , 5.11(s, 2H) , 4.92(d, J=4.6Hz, IH) , 3.95(s, 3H) , 3.73 (s, 3H) , 2.37 (m, IH)

EXAMPLE 7

Synthesis of 6- (1-hydroxyoctyl) -5 , 8-dimethoxy-l,4-naphtho¬ quinone

lg(2.05 mmole) of 2 -( 1-hydroxyoctyl) -1 , 4-dimethoxy- 5 , 8-dibenzyloxynaphthalene was dissolved in 20ml of anhy¬ drous tetrahydrofuran and then hydrogenated under atmos¬ pheric pressure for 24 hours by adding 0.05g of 5%-Pd/C thereto. The reaction mixture was filtered and concen¬ trated under reduced pressure. The residue was immedi¬ ately dissolved in 20ml of acetonitrile and then

1.12g(2.05 mmole) of CAN was added thereto, and the mixture was stirred for 10 minutes. The reaction mixture was extracted with dichloromethane. The extract was dried over anhydrous sodium sulfate and concentrated under reduced pressure to obtain the crude product which was then subjected to silica gel column chromatography (column size: 1.5X15cm) using n-hexane :ethyl acetate (2:1) mixed solvent as eluant to obtain 480mg of the title compound as a yellowish-red oil.

Yield : 78.9%

Rf : 0.71 (silica gel thin layer film, n-hexane:ethyl acetate=l:2) ---H-NMR (ppm, δ) : 7.54(s, IH) , 6.74(s, 2H) , 5.13 (m, IH) , 3.96(s, 3H) , 3.80(s, 3H) , 3.28(br s, IH) , 1.64(m, 2H) , 1.55-1.05 ( , 10H) , 0.87(d, J=6.0Hz, 3H) ¹³ C-NMR :

184.7, 184.1, 156.1, 150.3, 149.1, 138.7, 137.5, 124.4, 119.1, 117.0, 68.0, 61.9, 56.4, 38.2, 31.6, 29.1, 29.0, 25.7, 22.4, 13.8 IR (cm ^-1 ) : 3475, 2925, 1650, 1460

MASS : 346(M ⁺ , 51) , 331(13) , 247(100) , 229(5) , 219(9) , 204 (7) , 189(3) , 84 (34)

Example 8

Synthesis of 6- (1-hvdroxydecyl) -5 , 8-dimethoxy-l , 4-naphth¬ oquinone

2- (1-Hydroxydecyl) -1, 4-dimethoxy-5, 8-dibenzyloxynapht¬ halene was used as the starting material and treated according to the same procedure as Example 7 to obtain 470mg of the title compound.

Yield : 85%

Rf : 0.53 (silica gel thin layer film,

n-hexane:ethyl acetate=l:2) ^-H-NMR (ppm, δ) :

7.52(s, IH) , 6.76(s, 2H) , 5.11(m, IH) , 3.98(s, 3H) , 3.82(s, 3H) , 2.63(br s, IH) , 1.66(m, 2H) , 1.55-1.05 (m, 14H) , 0.87 (d, J=6.3Hz, 3H) ¹³ C-NMR :

184.9, 184.3, 156.3, 150.5, 148.8, 138.9, 137.7, 124.8, 119.5, 117.0, 68.5, 62.2, 56.6, 38.3, 31.8, 29.5, 29.4, 25.9, 22.6, 14.0 IR (cm ^-1 ) : 3475, 2925, 1650, 1460

MASS : 346(M ⁺ , 20) , 359(7), 247(100), 219(22), 189(8), 86(37), 84(53)

Example 9

Synthesis of 6- (1-hydroxytridecyl) -5 , 8-dimethoxy-l ,4-naph¬ thoquinone

2- (1-Hydroxytridecyl) -1,4-dimethoxy-5, 8-dibenzyloxyna- phthalene was used as the starting material and treated according to the same procedure as Example 7 to obtain 470mg of the title compound. Yield : 85%

Rf : 0.71 (silica gel thin layer film, n-hexane:ethyl acetate=l :2)

-- ^• H-NMR (ppm, δ) :

7.51(s, IH) , 6.77(s, 2H) , 5.12(m, IH) , 3.99(s, 3H) , 3.82(s, 3H) , 2.48(s, IH) , 1.70(m, 2H) , 1.55-1.05 (m, 20H) , 0.88(t, J=6.1Hz, 3H) ¹³ C-NMR :

184.9, 184.3, 156.3, 150.6, 148.7, 138.9, 138.0, 124.8, 119.5, 117.0, 68.8, 62.2, 56.6, 38.3, 31.9, 29.6, 29.4(5C) , 29.3, 22.6, 14.0 IR (cm ^-1 ) : 3450, 2925, 1655, 1460 MASS : 416(M ⁺ , 77), 401(28) , 386(22) , 247(100) , 229(5) , 219(12) , 204(7) , 189(3) , 57(2)

Example 10

Synthesis of 6- (1-acetoxyethyl) -5 , 8-dimethoxy-l , 4-naphtho¬ quinone

304mg(l mmole) of 6- (1-hydroxyethyl) -5, 8-dimethoxy- 1,4-naphthoquinone, 61. llmg(0.5 mmole) of 4-dimethylamino- pyridine and 206mg(l mmole) of N, ' -dicyclohexylcarbo- diimide were introduced into a two-necked flask and dis¬ solved in 8ml of anhydrous dichloromethane. To the mixture was added 60.3mg(l mmole) of acetic acid in the presence of nitorgen gas under cooling bath. The reac¬ tion mixture was stirred for 30 minutes and for further 3 hours at room temperature. After adding 30ml of hexane, the mixture was stirred for 10 minutes at room temperature and then allowed to stand. The precipitated insoluble material was filtered off. To the combined filtrate was added lOg of anhydrous magnesium sulfate, and the mixture was stirred and then filtered. The filtrate was concen¬ trated under reduced pressure to obtain the crude product which was dissolved in 5ml of hexane:ethyl acetate (1:3) and then subjected to silica gel column chromatography (column size : 1.5X15cm) using the same solvent system as eluant. The fractions from the red band were collected and then concentrated to obtain the title compound as a red oil .

Yield : 80%

Rf : 0.34 (silica gel thin layer film, hexane:ethyl acetate=3 : 1) -"Η-NMR (ppm, δ) :

7.32(s, IH) , 6.78(8, 2H) , 6.22(q, J=18.5Hz, IH) , 3.98(s, 3H) , 3.89(8, 3H) , 2.13(s, 3H) , 1.52(d, J=6.64Hz, 3H)

IR (cm ^-1 ) 2950, 1740, 1660, 1460

Example 11

Synthesis of 6- (l-propanoyloxyethyl) -5, 8-dimethoxy-l , 4- naphthoquinone

6- (1-Hydroxyethyl) -5, 8-dimethoxy-l,4-naphthoquinone was reacted with propionic acid according to the same proce¬ dure as Example 10 to obtain the title compound as a red oil .

Yield : 47% Rf : 0.36 (silica gel thin layer film, hexane:ethyl acetate=3:l) ¹ H-NMR (ppm, δ) :

7.31(8, IH) , 6.78(8, 2H) , 6.23(q, J=18.5Hz, IH) , 3.97(8, 3H) , 3.91(s, 3H) , 2.42(q, J=20.6Hz, 2H) , 1.53 (d, J=7.52Hz, 3H) , 1.18(t, J=12.2Hz, 3H) IR (cm ^-1 ) : 2950, 1740, 1660, 1460

Example 12 Synthesis of 6- (1-butanoyloxyethyl)-5 , 8-dimethoxy-l ,4-na¬ phthoquinone

6- (1-Hydroxyethyl) -5, 8-dimethoxy-l , -naphthoquinone was reacted with butanoic acid according to the same procedure as Example 10 to obtain the title compound as a red oil.

Yield : 48%

Rf : 0.38 (silica gel thin layer film, hexane:ethyl acetate=3:l) ¹ H-NMR (ppm, δ) :

7.32(s, IH) , 6.78(8, 2H) , 6.20(q, J=18.2Hz, IH) ,

3.97(8, 3H) , 3.91(s, 3H) , 3.38(t, J=14.7Hz, 2H) , 1.81-

1.48( , 5H) , 0.97(t, J=12.2Hz, 3H)

IR (cm ^-1 ) : 2950, 1730, 1660, 1460

Example 13

Synthesis of 6- (1-hexanoyloxyethyl) -5 , 8-dimethoxy-l, 4-na¬ phthoquinone

6- (1-Hydroxyethyl) -5, 8-dimethoxy-l,4-naphthoquinone was reacted with hexanoic acid according to the same procedure as Example 10 to obtain the title compound as a red oil.

Yield : 49%

Rf : 0.45 (silica gel thin layer film, hexane:ethyl acetate=3:l)

¹ H-NMR (ppm, δ) :

7.32(8, IH) , 6.79(s, 2H) , 6.23(q, J=18.1Hz, IH) , 3.98(s, 3H) , 3.91(8, 3H) , 2.39(t, J=13.9Hz, 2H) , 1.66- 1.31(m, 11H) , 0.88(t, J=12.0Hz, 3H) IR (cm ^-1 ) : 2950, 1730, 1660, 1460

Example 14

Synthesis of 6- (1-acetoxypropyl) -5, 8-dimethoxy-l , 4-naphth- oquinone

6- (1-Hydroxypropyl) -5, 8-dimethoxy-l, 4-naphthoquinone was reacted with acetic acid according to the same proce¬ dure as Example 10 to obtain the title compound as a yellow oil.

Yield : 52%

Rf : 0.34 (silica gel thin layer film, hexane:ethyl acetate=3:l) ¹ H-NMR (ppm, δ) :

7.24(8, IH) , 6.75(8, 2H) , 6.05(t, J=14.3Hz, IH) , 3.94(s, 3H) , 3.88(s, 3H) , 2.11(s, 3H) , 1.90-1.74 ( , 2H) , 0.92 (t, J=14.5Hz, 3H) IR (cm ^-1 ) : 2950, 1740, 1660, 1460

Example 15

Synthesis of 6- (1-propanoyloxypropyl) -5 , 8-dimethoxy-l ,4- naphthoquinone

6- (1-Hydroxypropyl) -5, 8-dimethoxy-l, -naphthoquinone was reacted with propionic acid according to the same procedure as Example 10 to obtain the title compound as a yellow oil.

Yield : 47% Rf : 0.36 (silica gel thin layer film, hexane:ethyl acetate=3:l) ¹ H-NMR (ppm, δ) :

7.24(s, IH) , 6.76(s, 2H) , 6.07(t, J=14.3Hz, IH) , 3.95(s, 3H) , 3.91(s, 3H) , 2.41(q, J=22.4Hz, 2H) , 2.00- 1.7(m, 2H) , 1.16(t, J=14.9Hz, 3H) , 0.94(t, J=14.5Hz, 3H) IR (cm ^-1 ) : 2950, 1740, 1660, 1460

Example 16

Synthesis of 6- (1-butanoyloxypropyl) -5 , 8-dimethoxy-l , 4- naphthoquinone

6- (1-Hydroxypropyl) -5, 8-dimethoxy-l,4-naphthoquinone was reacted with butanoic acid according to the same procedure as Example 10 to obtain the title compound as a yellow oil.

Yield : 48% Rf : 0.38 (silica gel thin layer film, hexane:ethyl acetate=3 :1) ¹ H-NMR (ppm, δ) :

7.26(s, IH) , 6.78(8, 2H) , 6.07(t, J=14.3Hz, IH) , 3.96(s, 3H) , 3.93(s, 3H) , 2.39(t, J=13.8Hz, 2H) , 2.04- 1.26(m, 7H) , 0.96(t, J=14.5Hz, 3H) IR (cm ^-1 ) : 2950, 1730, 1660, 1460

Example 17

Synthesis of 6- ( 1 -hexanoyloxypropyl ) - 5 , 8 -dimethoxy- l , 4 - naphthoquinone

6- (1-Hydroxypropyl ) -5 , 8-dimethoxy-l , 4-naphthoquinone was reacted with hexanoic acid according to the same procedure as Example 10 to obtain the title compound as a yellow oil .

Yield : 49%

Rf : 0.41 (silica gel thin layer film, hexane:ethyl acetate=3:l) --H-NMR (ppm, δ) :

7.25(8, IH) , 6.77(s, 2H) , 6.06(t, J=14.2Hz, IH) , 3.96(8, 3H) , 3.92(8, 3H) , 2.39(t, J=15.4Hz, 2H) , 1.83- 1.22 ( , 11H) , 0.88(t, J=13.2Hz, 3H) IR (cm ^-1 ) : 2950, 1730, 1660, 1460

Example 18

Synthesis of 6- (1-heptanoyloxypropyl) -5 , 8-dimethoxy-l , 4- naphthoquinone

6- (1-Hydroxypropyl) -5, 8-dimethoxy-l,4-naphthoquinone was reacted with heptanoic acid according to the same procedure as Example 10 to obtain the title compound as a yellow oil .

Yield : 49% Rf : 0.45 (silica gel thin layer film, hexane:ethyl acetate=3:l) ¹ H-NMR (ppm, δ) :

7.25(8, IH) , 6.73(s, 2H) , 6.05(t, J-=14.5Hz, IH) , 3.97(8, 3H) , 3.92(s, 3H) , 2.39(t, J=15.1Hz, 2H) , 2.12- 1.26(m, 13H) , 0.88(t, J=13.0Hz, 3H) IR (cm ^-1 ) : 2950, 1730, 1660, 1460

Example 19

Synthesis of 6- (1-acetoxybutyl) -5 , 8-dimethoxy-l , 4-naphth¬ oquinone

6- (1-Hydroxybutyl) -5, 8-dimethoxy-l, 4-naphthoquinone was reacted with acetic acid according to the same procedure as Example 10 to obtain the title compound as a yellow oil.

Yield : 79%

Rf : 0.17 (silica gel thin layer film, hexane:ethyl acetate=3 : 1) ¹ H-NMR (ppm, δ) :

7.32(s, IH) , 6.78(s, 2H) , 6.22(q, J=18.5Hz, IH) , 3.98(s, 3H) , 3.89(s, 3H) , 2.13(s, 3H) , 1.52(d, J=6.64Hz, 3H) IR (cm ^-1 ) : 2950, 1740, 1660, 1460

Example 20

Synthesis of 6- (1-propanoyloxybuty ) - 5 , 8-dimethoxy-l , 4 - naphthoquinone

6- (1-Hydroxybutyl) -5 , 8-dimethoxy-l , 4 -naphthoquinone was reacted with propionic acid according to the same proce¬ dure as Example 10 to obtain the title compound as a yellow oil.

Yield : 47% Rf : 0.19 (silica gel thin layer film, hexane: ethyl acetate=3:l) ¹ H-NMR (ppm, δ) :

7.31(s, IH) , 6.78(s, 2H) , 6.23(q, J=18.5Hz, IH) , 3.97(s, 3H) , 3.91(s, 3H) , 2.42(q, J=20.6Hz, 2H) , 1.53(d, J=7.52Hz, 3H) , 1.18(t, J=12.2Hz, 3H)

IR (cm ^-1 ) : 2950, 1740, 1660, 1460

Example 21

Synthesis of 6 - ( 1 -butanoyloxybutyl ) - 5 , 8 -dimethoxy- 1 , 4 - naphthoquinone

6- (1 -Hydroxybutyl ) -5 , 8 -dimethoxy-l , 4 -naphthoquinone was reacted with butanoic acid according to the same procedure as Example 10 to obtain the title compound as a yellow oil .

Yield : 48%

Rf : 0.22 (silica gel thin layer film, hexane:ethyl acetate=3:l) ¹ H-NMR (ppm, δ) :

7.32(s, IH) , 6.78(s, 2H) , 6.20(q, J=18.2Hz, IH) , 3.97(s, 3H) , 3.91(s, 3H) , 3.38(t, J=14.7Hz, 2H) , 1.81- 1.48 (m, 5H) , 0.97(t, J=12.2Hz, 3H) IR (cm ^-1 ) : 2950, 1730, 1660, 1460

Example 22

Synthesis of 6- (1-hexanoyloxybutyl) -5 , 8-dimethoxy-1 , 4- naphthoquinone

6- (1-Hydroxybutyl) -5, 8-dimethoxy-l, 4-naphthoquinone was reacted with hexanoic acid according to the same procedure as Example 10 to obtain the title compound as a yellow oil.

Yield : 49% Rf : 0.27 (silica gel thin layer film, hexane:ethyl acetate=3:l) ¹ H-NMR (ppm, δ) :

7.32(s, IH) , 6.78(s, 2H) , β.23(q, J=18.0Hz, IH) , 3.97(s, 3H) , 3.92(s, 3H) , 2.39(t, J=13.4Hz, 2H) , 1.66- 1.42 (m, 9H) , 0.88(t, J=12.2Hz, 3H) IR (cm ^-1 ) : 2950, 1730, 1660, 1460

Example 23

Synthesis of 6- (1-heptanoyloxybutyl) -5 , 8-dimethoxy-l , 4- naphtho uinone

6- (1-Hydroxybutyl) -5, 8-dimethoxy-1,4-naphthoquinone was reacted with heptanoic acid according to the same proce¬ dure as Example 10 to obtain the title compound as a yellow oil.

Yield : 49%

Rf : 0.28 (silica gel thin layer film, hexane:ethyl acetate=3:l) -- ^• H-NMR (ppm, δ) :

7.32(s, IH) , 6.79(s, 2H) , 6.23(q, J=l8.1Hz, IH) , 3.98(8, 3H) , 3.91(8, 3H) , 2.39(t, J=13.9Hz, 2H) , 1.66- 1.31 (m, 11H) , 0.88(t, J=12.0Hz, 3H) IR (cm ^-1 ) : 2950, 1730, 1660, 1460

Example 24

Synthesis of 6- (1-acetoxypentyl) -5 , 8-dimethoxy-l ,4-naphth¬ oquinone

6- (1-Hydroxypentyl) -5, 8-dimethoxy-l,4-naphthoquinone was reacted with acetic acid according to the same proce¬ dure as Example 10 to obtain the title compound as a yellow oil.

Yield : 80% Rf : 0.34 (silica gel thin layer film, hexane:ethyl acetate=3:l) -- ^■ H-NMR (ppm, δ) :

7.29(8, IH) , 6.81(s, 2H) , 6.15(t, J=12.9Hz, IH) , 4.00(s, IH) , 3.94(s, 3H) , 2.16(s, 3H) , 1.79-1.20 (m, 6H) , 0.92 (t, J=13.7Hz, 3H)

IR (cm ^-1 ) : 2950, 1740, 1660, 1460

Example 25

Synthesis of 6- (l-propanoyloxypentyl) -5 , 8-dimethoxy-l , 4- naphthoquinone

6- (1-Hydroxypentyl) -5, 8-dimethoxy-l,4-naphthoquinone was reacted with propionic acid according to the same procedure as Example 10 to obtain the title compound as a yellow oil .

Yield : 47%

Rf : 0.36 (silica gel thin layer film, hexane.-ethyl acetate=3 :1) ¹ H-NMR (ppm, δ) :

7.26(s, IH) , 6.78(s, 2H) , 6.12(t, J=12.5Hz, IH) , 3.97(s, 3H) , 3.93(s, 3H) , 2.43(q, J=21.4Hz, 2H) , 1.82- 1.2 ( , 9H) , 0.89(t, J=9.8Hz, 3H) IR (cm ^-1 ) : 2950, 1740, 1660, 1460

Example 26

Synthesis of 6- (1-butanoyloxypentyl) -5 , 8-dimethoxy-l , 4- naphthoquinone

6- (1-Hydroxypentyl) -5, 8-dimethoxy-l, 4-naphthoquinone was reacted with butanoic acid according to the same procedure as Example 10 to obtain the title compound as a yellow oil.

Yield : 48% Rf : 0.38 (silica gel thin layer film, hexane:ethyl acetate=3:l) ^-H-NMR (ppm, δ) :

7.28(8, IH) , 6.79(s, 2H) , 6.13(t, J=12.5Hz, IH) , 3.97(8, 3H) , 3.93(8, 3H) , 2.39(t, J=14.8Hz, 2H) , 1.82- 1.34 (m, 11H) , 0.97(t, J=13.7Hz, 3H) IR (cm ^-1 ) : 2950, 1730, 1660, 1460

Example 27

Synthesis of 6- ( 1 -hexanoyloxypentyl ) - 5 , 8 -dimethoxy- l , 4 - naphthoquinone

6- (1-Hydroxypentyl) -5 , 8-dimethoxy-l , 4 -naphthoquinone was reacted with hexanoic acid according to the same procedure as Example 10 to obtain the title compound as a yellow oil .

Yield : 49%

Rf : 0.41 (silica gel thin layer film, hexane:ethyl acetate=3:l) --H-NMR (ppm, δ) :

7.25(s, IH) , 6.78(s, 2H) , 6.10(t, J=13.0Hz, IH) , 3.96(s, 3H) , 3.92(s, 3H) , 2.39(t, J=14.7Hz, 2H) , 1.82- 1.29 (m, 12H) , 0.88(t, J=11.2Hz, 3H) IR (cm ^-1 ) : 2950, 1730, 1660, 1460

Example 28

Synthesis of 6- (1-heptanoyloxypentyl ) -5 , 8-dimethoxy-1 , 4- naphthoquinone

6- (1-Hydroxypentyl) -5, 8-dimethoxy-l, -naphthoquinone was reacted with butanoic acid according to the same procedure as Example 10 to obtain the title compound as a yellow oil.

Yield : 49% Rf : 0.45 (silica gel thin layer film, hexane:ethyl acetate=3:l) ¹ H-NMR (ppm, δ) :

7.26(s, IH) , 6.78(s, 2H) , 6.09(t, J=13.0Hz, IH) , 3.95(s, 3H) , 3.91(s, 3H) , 2.38(t, J=14.2Hz, 2H) , 1.81- 1.24 (m, 14H) , 0.86(t, J=11.5Hz, 6H) IR (cm ^-1 ) : 2950, 1730, 1660, 1460

Example 29

Synthesis of 6- (1-acetoxyhexyl) -5, 8-dimethoxy-l ,4-naphth¬ oquinone

6- (1-Hydroxyhexyl) -5, 8-dimethoxy-l,4-naphthoquinone was reacted with acetic acid according to the same procedure as Example 10 to obtain the title compound.

Yield : 52% Rf : 0.27 (silica gel thin layer film, hexane:ethyl acetate=2:l) ¹ H-NMR (ppm, δ) :

7.32(s, IH) , 6.78(s, 2H) , 6.22(q, J=18.5Hz, IH) , 3.98(s, 3H) , 3.89(8, 3H) , 2.13(s, 3H) , 1.52(d, J=6.64Hz, 3H)

IR (cm ^-1 ) : 2950, 1740, 1660, 1460

Example 30 Synthesis of 6 - ( 1 -propanoyloxyhexyl ) - 5 , 8 -dimethoxy- 1 , 4 - naphthoquinone

6 - ( 1 -Hydroxyhexyl ) -5 , 8 -dimethoxy- l , 4 -naphthoquinone was reacted with propionic acid according to the same proce - dure as Exampl e 1 0 to obtain the t i t l e compound as a yellow oil .

Yield : 47%

Rf : 0.19 (silica gel thin layer film, n-hexane:ethyl acetate=3:l)

¹ H-NMR (ppm, δ) :

7.31(s, 3H) , 6.78(8, 2H) , 6.23(q, J=18.5Hz, IH) , 3.97(s, 3H) , 3.91(s, 3H) , 2.42(q, J=20.6Hz, 2H) , 1.53(d, J=7.52Hz, 3H) , 1.18(t, J=12.2Hz, 3H) IR (cm ^-1 ) : 2950, 1740, 1660, 1460

Example 31

Synthesis of 6- (1-butanoyloxyhexyl) -5 , 8-dimethoxy-l , 4- naphthoquinone

6- (1-Hydroxyhexyl) -5, 8-dimethoxy-l, 4-naphthoquinone was reacted with butanoic acid according to the same procedure as Example 10 to obtain the title compound as a yellow oil .

Yield : 48%

Rf : 0.22 (silica gel thin layer film, hexane:ethyl acetate=2 : 1) -•-H-NMR (ppm, δ) :

7.32(s, IH) , 6.78(s, 2H) , 6.20(q, J=18.2Hz, IH) , 3.97(s, 3H) , 3.91(s, 3H) , 3.38(t, J=14.7Hz, 2H) , 1.81- 1.48(m, 5H) , 0.97(t, J=12.2Hz, 3H) IR (cm ^-1 ) : 2950, 1730, 1660, 1460

Example 32

Synthesis of 6- (1-hexanoyloxyhexyl) -5 , 8-dimethoxy-1 , 4- naphthoquinone

6- (1-Hydroxyhexyl) -5, 8-dimethoxy-l, 4-naphthoquinone was reacted with hexanoic acid according to the same procedure as Example 10 to obtain the title compound as a yellow oil.

Yield : 49% Rf : 0.27 (silica gel thin layer film, hexane:ethyl acetate=2 :1)

7.32(s, IH) , 6.78(s, 2H) , 6.23(q, J=18.0Hz, IH) , 3.97(s, 3H) , 3.92(s, 3H) , 2.39(t, J=13.4Hz, 2H) , 1.66- 1.42 (m, 9H) , 0.88(t, J=12.2Hz, 3H) IR (cm ^-1 ) : 2950, 1730, 1660, 1460

Example 33

Synthesis of 6- ( 1 -heptanoyloxyhexyl ) - 5 , 8 -dimethoxy- l , 4 - naphthoquinone

6- (1-Hydroxyhexyl) -5 , 8 -dimethoxy-l , 4-naphthoquinone was reacted with heptanoic acid according to the same proce¬ dure as Example 10 to obtain the t itle compound as a yellow oil .

Yield : 49%

Rf : 0.28 (silica gel thin layer film, hexane:ethyl acetate=2:l) ¹ H-NMR (ppm, δ) :

7.32(s, IH) , 6.79(s, 2H) , 6.23(q, J=18.1Hz, IH) , 3.98(s, 3H) , 3.91(s, 3H) , 2.39(t, J=13.9Hz, 2H) , 1.66- 1.31(m, 11H) , 0.88(t, J=12.0Hz, 3H) IR (cm ^-1 ) : 2950, 1730, 1660, 1460

Example 34

Synthesis of 6- (l-acetoxy-4-methylpentyl) -5 , 8-dimethoxy- 1 , 4-naphthoquinone

6- (l-Hydroxy-4-methylpentyl) -5, 8-dimethoxy-l, 4-naphth- oquinone was reacted with acetic acid according to the same procedure as Example 10 to obtain the title compound as a yellow oil.

Yield : 52% Rf : 0.26 (silica gel thin layer film, hexane:ethyl acetate=2:l) ¹ H-NMR (ppm, δ) :

7.28(8, IH) , 6.78(s, 2H) , 6.11(t, J=7.3Hz, IH) , 3.98(8, 3H) , 3.92(s, 3H) , 2.14(s, 3H) , 2.00-1.10 (m, 5H) , 0.87(d, J=6.3Hz, 6H) ¹³ C-NMR :

184.6, 184.1, 169.9, 156.2, 150.6, 145.2, 138.8,

137.7, 125.2, 120.2, 116.4, 70.7, 61.9, 56.6, 34.4, 33.7, 27.7, 22.5, 22.2, 21.0 IR (cm ^-1 ) : 2950, 1740, 1660, 1460

MASS : 360(M ⁺ , 63) , 318(46) , 303(37) , 288(100) , 247(51) , 231(24), 115(5) , 219(36) , 86(37) , 84(54)

Example 35

Synthesis of 6- (l-butanoyloxy-4-methylpentyl) -5 , 8-dimet- hoxy-1 ,4-naphthoquinone

6- (1-Hydroxy-4-methylpentyl) -5, 8-dimethoxy-l, 4-naphth¬ oquinone was reacted with butanoic acid according to the same procedure as Example 10 to obtain the title compound as a yellow oil.

Yield : 48%

Rf : 0.35 (silica gel thin layer film, hexane:ethyl acetate=2:l) ^-H-NMR (ppm, δ) :

7.28(s, IH) , 6.79(s, 2H) , 6.11(t, J=7.0Hz, IH) , 3.97(s, 3H) , 3.93(s, 3H) , 2.39(t, J=7.5Hz, 2H) , 1.95- 1.10 (m, 7H) , 0.97(t, J=7.3Hz, 3H) , 0.88(d, J=6.3Hz, 6H) ¹³ C-NMR :

184.6, 184.0, 172.6, 156.1, 150.5, 145.4, 138.7,

137.7, 125.2, 120.1, 116.2, 70.4, 61.8, 56.5, 36.2, 34.4, 33.7, 27.6, 22.5, 22.1, 18.4, 13.6

IR (cm ^-1 ) : 2950, 1735, 1660, 1460 MASS : 388(M ⁺ , 44) , 338(37) , 318(73) , 288(100) , 247(22) , 245(43) , 229(29) , 219(25) , 217(23), 197(15) , 165 (21) , 121 (12) , 71 (40)

Example 36

Synthesis of 6- (l-hexanoyloxy-4-methylpentyl) -5 , 8-dimet■ hoxy-1 , 4-naphthoquinone

6- (l-Hydroxy-4-methylpentyl) -5, 8-dimethoxy-l,4-naphth¬ oquinone was reacted with hexanoic acid according to the same procedure as Example 10 to obtain the title compound as a yellow oil.

Yield : 45%

Rf : 0.36 (silica gel thin layer film, hexane:ethyl acetate=2:l) ---H-NMR (ppm, δ) : 7.28(8, IH) , 6.79(8, 2H) , 6.11(t, J=7.0Hz, IH) , 3.98(s, 3H) , 3.94(s, 3H) , 2.41(t, J=7.5Hz, 2H) , 2.00- 1.10 ( , HH) , 0.95-0.70(m, 9H) ¹³ C-NMR :

184.6, 184.0, 172.7, 156.1, 150.5, 145.5, 138.7, 137.6, 125.2, 120.1, 116.2, 70.4, 61.8, 56.5, 34.4, 34.2, 33.7, 31.1, 22.5, 27.7, 24.6, 22.4, 22.1, 13.7 IR (cm ^-1 ) : 2950, 1735, 1660, 1460

MASS : 416(M ⁺ , 33) , 318(93) , 289(20) , 288(100) , 247(20) , 219(24) , 218(11) , 173(3) , 149(4) , 99(43) , 71(27) , 43(20)

Example 37

Synthesis of 6- [1- (trans-2-pentenoyloxy) -4-methylpentyl1 - 5, 8-dimethoxy-l , 4-naphthoquinone

6- (l-Hydroxy-4-methylpentyl) -5, 8-dimethoxy-l,4-naphth¬ oquinone was reacted with trans-2-pentenoic acid according to the same procedure as Example 10 to obtain the title compound as a yellow oil.

Yield : 35%

Rf : 0.35 (silica gel thin layer film, hexane:ethyl acetate=2 : 1) ¹ H-NMR (ppm, δ) :

7.28(s, IH) , 7.03(dt, J=15.5, 6.5Hz, IH) , 6.13(t, J=6.5Hz, IH) , 5.91(dt, J=15.5, 1.0Hz, IH) , 3.96(s,

3H) , 3.94(s, 3H) , 2.19(t, J=7.7Hz, 2H) , 2.10-1.10 (m,

5H) , 1.10(t, J=7.5Hz, 3H) , 0.88(d, J=6.3Hz, 6H) ¹³ C-NMR :

184.7, 184.1, 165.8, 156.1, 151.9, 150.6, 145.5, 138.8, 137.7, 137.7, 125.2, 120.1, 119.8, 116.4, 70.6,

61.9, 56.6, 34.5, 33.8, 33.7, 27.7, 25.3, 22.5, 22.2,

12.0 IR (cm ^-1 ) : 2950, 1720, 1660, 1460

MASS : 400(M ⁺ , 16) , 318(67) , 288(29) , 229(5), 219(8), 229(29) , 149(5) , 97(6), 86(9) , 93(100) , 57(9)

Example 38

Synthesis of 6- [1- (trans-3-hexenoyloxy) -4-methylpentyl1 - 5 , 8-dimethoxy-l , 4-naphthoquinone

6- (l-Hydroxy-4-methylpentyl) -5, 8-dimethoxy-l,4-naphth¬ oquinone was reacted with trans-3-hexenoic acid according to the same procedure as Example 10 to obtain the title compound as a yellow oil.

Yield .- 45%

Rf : 0.36 (silica gel thin layer film, hexane:ethyl acetate=2:l) ¹ H-NMR (ppm, δ) :

7.27(8, IH) , 6.79(8, 2H) , 6.10(t, J=6.3Hz, IH) , 5.61 (m, 2H) , 3.97(s, 3H) , 3.93(s, 3H) , 3.12(d, J=6.0Hz, 2H) , 2.25-1.10(m, 7H) , 0.99(t, J=7.8Hz, 3H) , 0.88(d, J=6.0Hz, 6H) ¹³ C-NMR :

184.5, 184.0, 171.0, 156.1, 151.4, 145.2, 138.7,

137.6, 137.7, 136.7, 125.2, 120.0, 119.9, 116.2, 70.8, 61.8, 56.5, .38.1, 34.3, 33.7, 27.6, 25.3, 22.4, 22.1, 13.2 IR (cm ^-1 ) : 2950, 1740, 1660, 1460

MASS : 414(M ⁺ , 17) , 318(28) , 302(27) , 301(45) , 288(42) , 231(20) , 219(5) , 188(9) , 97(44) , 86(64) , 84(100),

57 ( 9 )

Example 39 Synthesis of 6- (l-octanoyloxy-4-methylpentyl) -5 , 8-dimet¬ hoxy-1,4-naphthoquinone

6- (l-Hydroxy-4-methylpentyl) -5, 8-dimethoxy-l,4-naphth¬ oquinone was reacted with octanoic acid according to the same procedure as Example 10 to obtain the title compound as a yellow oil.

Yield : 45%

Rf : 0.41 (silica gel thin layer film, hexane:ethyl acetate=2:l)

^-H-NMR (ppm, δ) :

7.26(s, IH) , 6.78(s, 2H) , 6.10(t, J=6.5Hz, IH) , 3.97(s, 3H) , 3.93(s, 3H) , 2.40(t, J=7.5Hz, 2H) , 2.00- 1.10(m, 15H) , 0.95-0.70(m, 9H) ¹³ C-NMR :

184.6, 184.1, 172.8, 156.2, 150.6, 145.5, 138.8,

137.7, 125.3, 120.2, 116.3, 116.3, 70.6, 61.9, 56.6, 34.5, 34.4, 33.8, 31.5, 29.6, 29.1, 28.8, 27.7, 25.0, 22.5, 22.2, 13.9 IR (cm ^-1 ) : 2950, 1735, 1640, 1460

MASS : 444(M ⁺ , 37) , 318(89) , 289(20) , 288(100) , 269(13) , 247(11) , 219(14), 144(5) , 127(14) , 98(5) , 57(12)

Example 40

Synthesis of 2- (l-methoxy-4-methylpentyl) -1 , 4 , 5 , 8-tetra¬ methoxynaphthalene

390mg(1.12 mmole) of 2- (1-hydroxy-4-methylpentyl) - 1, 4, 5, 8-tetramethoxynaphthalene and sodium hydride (55% in oil, 234mg, 5.6 mole) were dissolved in 10ml of anhydrous tetrahydrofuran and then refluxed for 3 hours in the

presence of nitrogen gas with addition of 350μl (5.6 mmole) of iodomethane. To the reaction mixture was added 20ml of ice water. Then, the mixture was extracetd with dichloromethane, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The residue was purified with silica gel column chromatography to obtain 350mg of the title compound as a pale yellow oil.

Yield : 86% Rf : 0.49 (silica gel thin layer film, hexane:ethyl acetate=2:l) ---H-NMR (ppm, δ) :

6.94(s, IH) , 6.38(s, 2H) , 4.78 ( , IH) , 3.95(s, 6H) , 3.77(8, 3H) , 3.25(s, 3H) , 1.90-1.10 ( , 5H) , 0.87(d, J=5.5Hz, 6H) ¹³ C-NMR :

153.6, 151.4, 150.2, 147.5, 132.5, 122.4, 120.7, 108.3, 107.5, 105.2, 77.3, 62.5, 57.7, 56.9, 56.8, 56.6, 35.5, 35.1, 28.0, 22.5, 22.4 IR (cm ^-1 ) : 2925, 1600, 1450, 1360

MASS : 362(M ⁺ , 100) , 330(46) , 291(60) , 261(17) , 231(13) , 84(9)

Example 41

Synthesis of 2- (l-ethoxy-4-methylpentyl) -1,4 , 5 , 8-tetramet¬ hoxynaphthalene

2- (l-Hydroxy-4-methylpentyl) -1,4,5, 8-tetramethoxynaph- thalene was reacted with iodomethane according to the same procedure as Example 40 to obtain the title compound as a pale yellow oil.

Yield : 85% Rf : 0.50 (silica gel thin layer film, hexane:ethyl acetate=2 : 1) ¹ H-NMR (ppm, δ) :

6.98(8, IH) , 6.82(8, 2H) , 4.86 (m, IH) , 3.94(s, 6H) , 3.89(8, 3H) , 3.76(8, 3H) , 3.38(q, J=7.0Hz, 3H) , 1.90- 1.30(m, 5H) , 1.19(t, J=7.0Hz, 3H) , 0.87(d, J=5.0Hz, 6H) ¹³ C-NMR :

153.5, 151.5, 150.2, 147.3, 133.4, 122.5, 120.2, 108.3, 107.6, 105.5, 75.5, 64.1, 62.5, 57.8, 56.9, 56.8, 35.7, 35.3, 28.0, 22.6, 22.5, 15.4 IR (cm ^-1 ) : 2950, 1600, 1450, 1360 MASS : 376(M ⁺ , 12) , 305(17) , 276(6) , 231(3) , 86(100) , 84 (100)

Example 42 Synthesis of 2- (1-isopentoxy-4-methylpentyl) -1 , 4 , 5 , 8- tetramethoxynaphthalene

2- (l-Hydroxy-4-methylpentyl) -1,4,5, 8-tetramethoxynaph¬ thalene was reacted with isopentylbromide according to the same procedure as Example 40 to obtain the title compound as a pale yellow oil.

Yield : 72%

Rf : 0.61 (silica gel thin layer film, hexane:ethyl acetate=2 *.1)

---H-NMR (ppm, δ) :

6.96(s, IH) , 6.82(8, 2H) , 4.83 (m, IH) , 3.93(s, 6H) , 3.90(s, 3H) , 3.75(s, 3H) , 3.33(t, J=6.3Hz, 2H) , 1.90- 1.10 (m, 8H) , 0.87(d, J=6.3Hz, 6H) , 0.83(d, J=6.3Hz, 6H)

¹³ C-NMR :

153.6, 151.5, 150.3, 147.3, 133.6, 122.6, 120.2, 108.3, 107.6, 105.7, 75.8, 67.4, 62.6, 57.8, 57.0(2C), 38.9, 35.9, 35.3, 28.0, 25.1, 22.7, 22.6(2C) , 22.5 IR (cm ^-1 ) : 2950, 1600, 1460, 1360

MASS : 418(M ⁺ , 1) , 307(3) , 263(6) , 237(11) , 149(3) , 115(3) , 91(6) , 71(3) , 55(24) , 43(100)

Example 43

Synthesis of 2- (1-pentoxy-4-methylpentyl) -1 , 4 , 5 , 8-tetra- methoxynaphthalene

2- (l-Hydroxy-4-methylpentyl) -1,4, 5, 8-tetramethoxynaph¬ thalene was reacted with pentylbromide according to the same procedure as Example 40 to obtain the title compound as a pale yellow oil .

Yield : 83%

Rf : 0.60 (silica gel thin layer film, hexane:ethyl acetate=2:l)

6.97(s, IH) , 6.82(8, 2H) , 4.83 (m, IH) , 3.94(s, 6H) , 3.75(8, 3H) , 3.30(t, J=6.3Hz, 2H) , 1.85-1.10 (m, 11H) , 0.95-0.85(m, 9H) ¹³ C-NMR :

153.5, 151.5, 150.3, 147.3, 133.5, 122.5, 120.2, 108.3, 107.6, 105.6, 75.6, 69.0, 62.6, 57.8, 56.9(2C) , 35.8, 35.3, 29.6, 28.5, 28.0, 22.6, 22.5, 22.4, 14.0 IR (cm ^-1 ) : 2950, 1600, 1460, 1360

Example 44 Synthesis of 2- (l-heptyloxy-4-methylpentyl) -1 , 4 , 5 , 8-tetra¬ methoxynaphthalene

2- (l-Hydroxy-4-methylpentyl) -1, 4, 5, 8-tetramethoxynaph¬ thalene was reacted with heptylbromide according to the same procedure as Example 40 to obtain the title compound as a pale yellow oil.

Yield : 72%

Rf : 0.62 (silica gel thin layer film, hexane:ethyl acetate=2 :1)

---H-NMR (ppm, δ) :

6.98(s, IH) , 6.82(s, 2H) , 4.84 (m, IH) , 3.94(s, 6H) ,

3.76(s, 3H) , 3.31(t, J=6.3Hz, 2H) , 1.90-1.10 (m, 15H) ,

0.95-0.75(m, 9H) ¹³ C-NMR :

153.5, 151.5, 150.2, 147.2, 133.5, 122.5, 120.2, 108.3, 107.6, 105.6, 75.6, 69.0, 62.5, 57.8, 56.9,

35.8, 35.3, 31.8, 30.0, 29.6, 29.3, 28.3, 26.3, 22.6,

22.5, 22.4, 14.0 IR (cm ^-1 ) : 2950, 1600, 1460, 1360

Example 45

Synthesis of 2- (l-dodecyloxy-4 -methylpentyl) -1 , 4 , 5 , 8-tet¬ ramethoxynaphthalene

2- (l-Hydroxy-4 -methylpentyl) -1 , 4 , 5 , 8-tetramethoxynaph¬ thalene was reacted with dodecylbromide according to the same procedure as Example 40 to obtain the title compound as a pale yellow oil.

Yield : 76%

Rf : 0.39 (silica gel thin layer film, hexane: ethyl acetate=2:l) ^••• H-NMR (ppm, δ) :

6.96(s, IH) , 6.82(s, 2H) , 4.83 (m, IH) , 3.93(s, 6H) , 3.89(s, 3H) , 3.75(s, 3H) , 3.30(t, J=6.3Hz, 2H) , 1.90-

1.10 (m, 25H) , 1.90-1.75 (m, 9H) ¹³ C-NMR :

153.5, 151.5, 150.3, 147.3, 133.6, 124.0, 120.2, 108.4, 107.7, 105.7, 75.5, 69.1, 62.5, 57.9, 56.9(2C) , 35.8, 35.7, 35.5, 31.9, 29.9, 29.6, 29.4, 29.3, 28.0, 26.4, 22.6, 22.5, 14.0 IR (cm ^-1 ) : 2925, 1600, 1460, 1320

Example 46

Synthesis of 6- (l-methoxy-4-methylpentyl) -5 , 8-dimethoxy- 1 ,4-naphthoquinone

260mg of 6- (1-methoxy-4-methylpentyl) -1,4, 5, 8-tetrame¬ thoxynaphthalene was dissolved in 5ml of acetonitrile and then a solution of 983mg(1.79 mmole) of cerium ammonium nitrate (IV) dissolved in 5ml of distilled water was added dropwise thereto over 30 minutes under cooling bath. The mixture was stirred for 2 hours at room temperature and 10ml of distilled water was added thereto. The reaction mixture was extracted with dichloromethane solvent and the extract was concentrated under reduced pressure. The residue was purified with silica gel column chromatography to obtain 85mg of the title compound as a yellow oil.

Yield : 36%

Rf : 0.33 (silica gel thin layer film, hexane:ethyl acetate=2:l)

^■• -H-NMR (ppm, δ) :

7.43(s, IH) , 6.80(s, 2H) , 4.63 (m, IH) , 4.00(s, 3H) , 3.29(s, 3H) , 1.90-1.10(m, 5H) , 0.87(t,

156.4, 151.3, 146.7, 138.8, 124.9, 77.6, 62.0, 57.2, 56.5, 35.3, 34.7, 27.7, 22.5, 22.2 IR (cm ^-1 ) : 2950, 1650, 1460, 1250 MASS : 332(M ⁺ , 74) , 301(9) , 262(45) , 261(100) , 231(21) , 201(17) , 173(5) , 86(29) , 84(48) , 45(94)

Example 47 Synthesis of 6- (l-ethoxy-4-methylpentyl) -5 , 8-dimethoxy- 1 , 4-naphthoquinone

6- (l-Ethoxy-4-methylpentyl) -1,4,5, 8-tetramethoxynaph¬ thalene was used as the starting material and treated according to the same procedure as Example 46 to obtain the title compound as a yellow oil.

Yield : 36%

Rf : 0.40 (silica gel thin layer film, hexane:ethyl acetate=2:l) - ^■• H-NMR (ppm, δ) : 7.50(8, IH) , 6.80(s, 2H) , 4.73(m, IH) , 4.01(s, 3H) , 3.85(s, 3H) , 3.43(q, J=7.0Hz, 2H) , 1.90-1.10(m, 5H) , 1.23(t, J=7.0Hz, 3H) , 0.88(d, J=6.0Hz, 6H) ¹³ C-NMR :

184.6, 183.9, 156.2, 151.0, 147.4, 138.6, 137.4, 124.7, 119.6, 116.6, 75.5, 64.7, 61.8, 56.3, 35.3, 34.7, 27.6, 22.3, 22.1, 15.1 IR (cm ^-1 ) : 2950, 1650, 1455, 1250

MASS : 346(M ⁺ , 31) , 275(100) , 247(32) , 219(16) , 204(22), 187(13) , 147(6) , 118(5) , 84(19) , 77(6) , 55(11)

Example 48

Synthesis of 6- Tl- (3-methylbutoxy) -4-methylpentyl] -5 , 8- dimethoxy-1 , 4-naphthoquinone

6- [1- (3-methylbutoxy) -4-methylpentyl] -1,4,5, 8-tetrame¬ thoxynaphthalene was used as the starting material and treated according to the same procedure as Example 46 to obtain the title compound as a yellow oil.

Yield : 36%

Rf : 0.53 (silica gel thin layer film, hexane:ethyl acetate=2:l) ¹ H-NMR (ppm, δ) : 7.47(s, IH) , 6.79(s, 2H) , 6.49(m, IH) , 3.99(s, 3H) , 3.84(s, 3H) , 3.36(t, J=6.3Hz, 2H) , 1.90-1.10 (m, 8H) , 0.91(d, J=6.3Hz, 6H) , 0.88(d, J=6.3Hz, 6H) ¹³ C-NMR :

184.9, 184.2, 156.3, 151.2, 147.7, 138.8, 137.5, 124.9, 119.7, 116.8, 75.9, 68.0, 62.0, 56.4, 38.6, 35.5, 34.8, 27.7, 24.8, 22.5, 22.4, 22.2 IR (cm ^-1 ) : 2950, 1660, 1460, 1330

MASS : 388(M ⁺ , 7), 317(27), 249(59) , 204(7), 187(4),

145(3), 115(5), 84(7) , 71(36) , 55(13) , 43(100)

Example 49

Synthesis of 6- (l-pentoxy-4-rethylpentyl) -5 , 8-dimethoxy- 1,4-naphthoquinone

6- (l-Pentoxy-4-methylpentyl) -1,4,5, 8-tetramethoxynaph- thalene was used as the starting material and treated according to the same procedure as Example 46 to obtain the title compound as a yellow oil.

Yield : 36% Rf : 0.46 (silica gel thin layer film, hexane:ethyl acetate=2:l) ¹ H-NMR (ppm, δ) :

7.47(s, IH) , 6.78(s, 2H) , 4.68(m, IH) , 3.99(s, 3H) , 3.83(s, 3H) , 3.33(t, J=6.3Hz, 2H) , 1.80-1.10 (m, HH) , 0.95-0.75(m, 9H) ¹³ C-NMR :

185.0, 184.3, 156.4, 151.3, 147.7, 138.8, 137.6, 124.9, 119.7, 116.9, 75.9, 69.8, 62.0, 56.5, 36.6, 35.0, 29.5, 28.4, 27.8, 22.6, 22.4, 22.3, 13.9 IR (cm ^-1 ) : 2925, 1650, 1460

Example 50

Synthesis of 6- (l-heptoxy-4-methylpentyl) -5 , 8-dimethoxy- 1,4-naphthoquinone

6- (l-Heptoxy-4-methylpentyl) -1,4, 5, 8-tetramethoxynaph¬ thalene was used as the starting material and treated according to the same procedure as Example 46 to obtain the title compound as a yellow oil.

Yield : 28%

Rf : 0.44 (silica gel thin layer film, hexane:ethyl acetate=2 : 1) ¹ H-NMR (ppm, δ) :

7.48(8, IH) , 6.79(s, 2H) , 4.69(t, J=7.0Hz, IH) , 3.99(8, 3H) , 3.84(s, 3H) , 3.34(t, J=6.3Hz, 2H) , 1.80- 1.10 (m, 15H) , 0.95-0.75(m, 9H) ¹³ C-NMR :

184.9, 184.2, 156.4, 151.2, 138.8, 137.6, 124.9, 119.7, 116.8, 75.9, 69.8, 61.9, 56.5, 35.6, 34.9, 31.7, 29.8, 28.9, 27.7, 26.2, 22.6, 22.4, 22.3, 13.9 IR (cm ^-1 ) : 2925, 1650, 1460

MASS : 416(M ⁺ , 29) , 346(34) , 345(100) , 302(11), 248(60) , 247(100) , 115(5) , 219(23) , 204(15) , 189(5) , 57(62)

Example 51

Synthesis of 6- (1-n-dodecyloxy-4-methylpentyl) -5 , 8-dimet¬ hoxy-1 , 4-naphthoquinone

6- (1-n-Dodecyloxy-4-methylpentyl) -1,4,5, 8-tetramethox¬ ynaphthalene was used as the starting material and treated according to the same procedure as Example 46 to obtain the title compound as a yellow oil.

Yield : 31%

Rf : 0.63 (silica gel thin layer film, hexane:ethyl acetate---2 :1) ¹ H-NMR (ppm, δ) :

6.96(s, IH) , 6.82(s, 2H) , 4.83 (m, IH) , 3.93(s, 3H) , 3.89(8, 3H) , 3.75(s, 3H) , 3.30(t, J=6.3Hz, 2H) , 1.90- 1.10(m, 25H) , 0.90-0.75(m, 9H) ¹³ C-NMR :

185.1, 185.0, 153.8, 153.4, 151.0, 133.4, 121.2, 121.1, 120.4, 120.0, 75.2, 70.0, 56.8, 56.7, 34.7, 34.1, 31.8, 29.8, 29.8, 29.5, 29.4, 29.3, 27.9, 26.1, 22.7, 22.6, 22.3, 14.0 IR (cm ^-1 ) : 2925, 1650, 1470, 1275

TEST 1 : Experiment for cvtotoxic activity

A. Cytotoxic activity against L1210 cells

To obtain L1210 cells of logarithmic phase to be used in the cytotoxicity test, before 24 hours from initiation of the experiment Fisher medium which was previously warmed to 36 to 37°C was introduced into a 250ml Erlenmey- er flask having a rotary stopper and L1210 cell was inocu- lated on the medium in the concentration of 2-3X10 ⁵ cells/ml and then cultured. The culture solution thus obtained was diluted with a fresh medium to prepare L1210 cell suspension having the concentration of 0.8-1.0X10° cells/ml .

The test samples were dissoved in a suitable amount of ethanol or dimethylsulfoxide just before the experiment to obtain the sample solution having the known concentration. 0.1ml of this solution was diluted ten times with 0.9ml of fresh medium to obtain the sample dilution. To each test tube having a rotary stopper were added 100, 50, 25μl, respectively, of the sample dilutions and then added 5ml of the cell suspension (5X10 " cells/ml) prepared above to use as the test group. In each of the test tubes (2/n : n = number of test samples) for the control group, only 5ml of the cell suspension was introduced. All test tubes were cultured for 48 hours in a C0 ₂ incubator at 37°C and then the number of cells was counted using haemacytometer.

B. Cytotoxic activity against K-562 cells

As in the test for cytotoxicity aginst L1210 cells above, the test samples were dissolved in a suitable amount of ethanol or dimethylsulfoxide . 0.1ml of the resulting sample solution was mixed with 0.9ml of the fresh medium to obtain the sample dilution. This sample

dilution was taken in an amount of 100, 50 and 250xl, respectively, by means of a micropipette and added to the test tube having two rotary stopper. The activated K-562 cells, which was cultured before 24 hours from initiation of the experiment, were diluted to 1X10 ⁵ cells/ml and added in an amount of 5ml to each of the test tubes for the test group and the control group (2/n : n=number of the test samples) . All test tubes were cultured for 48 hours in a C0 ₂ incubator at 37°C and then the number of cells was counted using haemacytometer.

^ED 50 ^va l ^ue i- ^s given as the concentration of the test sample to inhibit the growth of cancer cells by 50% of the control group and determined according to the method described in NIC (National Cancer Institute, USA) manual. The growth rate Y (%) of cells in the test group at each concentration was calculated according to the following equation:

Y(%) = t(T-Co) / (C-Co)] X 100

In the above equation, T means the average cell number per ml in the test group after incubation for 48 hours in the presence of the test samples in each concentration, C means the average cell number per ml in the control group after incubation for 48 hours, and Co means the average cell number per ml in the control group at the beginning of incubation. The Y(%) value at each concentration and log _1Q value of each concentration were obtained and then the regression curve was constructed from the obtained values by means of the following equation. In this case, when all the Y(%) value obtained at each concentration is greater than 55% or lower than 45%, the repeated experi- ment was conducted.

To construct the regression curve Y=A+BX the values A

and B were obtained using the following equation.

N-Σ(Xi-Yi) - (ΣXi) • (∑Yi) B = Slope =

N-Σ(Xi) ² - (∑xi) ²

ΣYi ΣXi

A = Axis - B'

N N

In the above, the value N is a selected point which is greater than 2 and lower than, or identical with, the number of cencentration of the test sample, Xi is log (concentration) i, and Yi is the growth rate at (concen¬ tration)!. The ED ₅₀ values of the test samples are calculated from slope and axis of the regression curve.

C. Cytotoxicity against A549 cancer cells

The cytotoxicity against A549 cancer cells was deter¬ mined according to a sulforhodamin B(SRB) method which has been developed to determine in vitro anti-cancer activity of the drug. The sub-cultured cells were removed from the adhering surface with trypsin-CDTA solution and dis¬ tributed to a 24-well flat-bottom microplate (Falcon) in an amount of 8X10 ⁴ cells (A549) per each well. The distrib- uted cells were adhered to the bottom of the well by culturing in a C0 ₂ incubator for 24 hours and then the medium was removed using an aspirator. The solution of the test compound which was diluted with the medium in the log-dose of 6 concentrations was added to each well having adhered A549 cells in an amount of lOOμl in a triple manner. The plate was cultured for further 48 hours. In this procedure, the diluted solution of the test com-

pound was filtered through a 0.22μm filter before adding to the cells to maintain the aseptic condition of the experi¬ ment. The incubation of cells with the test compound was continued for 48 hours and then the medium was removed from each well. lOOμl of 10% trichloroacetic acid (TCA) was added to each well and the plate was allowed to stand at 4°C for one hour to fix the cells to the bottom of the plate. After the cell is fixed, the plate was washed five or six times with water to completely remove any remaining TCA solution and then dried at room temperature so that any water cannot be remained. To the completely dried plate was added 250μl of a dyeing solution, which was prepared by dissolving 0.4% SRB in 1% acetic acid solution, per each well and the plate was allowed to stand for 30 minutes to dye the cells. The plate was washed again five or six times with 1% acetic acid solution to remove SRB not bound to the cells. The dyed cell plate was dried again at room temperature and then the dyeing solution was extracted with a given amount of lOmM tris to the extent so that O.D. value of the control group at 520nm can be 0.8-1.0A. Then, ED ₅₀ value was determined by measuring the optical density of the solution at 520nm. To calculate the effect of the test compound on cancer cells, cell number in the presence of the test compound (Tz) , cell number when cancer cells were cultured in the medium without the test compound (C) and cell number when cancer cells were cultured at each concentration of the test compound (T) were measured.

The anti-cancer activity of the test compound was calculated according to the following equation. That is, in the case of Tz≥T the equation (T-Tz) / (C-Tz) X100 was used; and in the case of Tz<T the equation (T-Tz) /TzXIOO was used. The concentration of the test compound which inhibits the growth of cancer cells by 50%, IC _5Q , was calculated from the obtained values above by means of a data regression function of LOTUS programme and then the

cytotoxicities of the test compounds were compared.

The results of the experiments A, B and C are de¬ scribed in the following Table 1. In the above experi- ments, 5-fluorouracil which has been known as a potent anti-cancer agent was used as the comparative drug.

Table 1. Cytotoxicity of the compound of formula (I)

(unit : μg/ml)

Table 1 (continued)

Table 1 (continued)

As can be seen from the above experimental results, the naphthoquinone derivative of formula (I) according to the present invention exhibits a substantially identical or more potent cytotoxic activity against cancer cells such as L1210, K562 and A549 cells in comparison with 5- fluorouracil which has been already known as a potent anti-cancer agent. Therefore, it is apparent that the compound of formula (I) according to the present invention can be used as a potent anti-cancer agent in the clinical field.

TEST 2 : Life lengthening effect in ICR mouse suffering from S-180 sarcoma

In this experiment, healthy male ICR mouse weighing 20 to 25g were used as the test animal and were fed with water and feed without any restriction in the chamber controlled at the temperature of 23 to 24°C. As the feed, the antibiotic-free feed for mouse was used.

S-180 cells which were incubated for 7 days within abdominal cavity of ICR mouse were separated together with ascites . To the separated cells was added steri- lized cold physiological saline and the mixture was cen¬ trifuged with 400xg for 2 minutes to separate the cell precipitate. The separated cell precipitate was suspend¬ ed again in sterilized cold physiological saline and then centrifuged to remove the supernatant. Only S-180 cells were taken excluding any red blood cells incorporated therein, washed three times with the same method, and then suspended to obtain the cell suspension having the concen¬ tration of 10 cells/ml as counted by means of a haemocy- tometer. Each 0.1ml of this cell suspension was trans- planted in an abdominal cavity.

After 24 hours from the transplantation, mouse were

divided so that each group contains 8 to 9 mouse. The test sample was dissolved in a given amount of dimethyl- sulfoxude to prepare the stock solution which was then stored at 4°C. 30μl of the stock solution was taken, mixed with 1.5ml of physiological saline and then injected intraperitoneally to the test animal in an amount of 0.1ml. The control group was given only 2% dimethylsul- foxide-physiological saline solution via injection. The test sample was intraperitoneally injected a total of 7 to 8 times in the manner that the injection is conducted for 2 to 4 days in an amount of 0.1ml per day and then discon¬ tinued for one day. The survival rate was calculated on the basis of the date on which all the first control group is died (approximately 18 to 20 days) . The survival rate (T/C, %) was calculated by the following equation as proposed in NIC's protocol :

Average survived period in the test group Survival rate (T/C, %) = X 100

Average survived period in the control group

The results as obatined above are described in the following Table 2.

Table 2. Life lengthening effect of the compound of formu¬ la (I) in ICR mouse suffering from S-180 sarcoma

As can be seen from the above experimental result, it is apparent that the compound of the present invention exhibits an excellent life lengthening effect in mouse suffering from S-180 sarcoma as well as a potent cytotoxic activity against cancer cells, and therefore can be used as a clinically useful anti-cancer agent.