WO2011078121A1

WO2011078121A1 - Anti-cancer agent

Info

Publication number: WO2011078121A1
Application number: PCT/JP2010/072901
Authority: WO
Inventors: 宣彦大原; 一博中對
Original assignee: 日本化学工業株式会社
Priority date: 2009-12-21
Filing date: 2010-12-20
Publication date: 2011-06-30
Also published as: JPWO2011078121A1; CN102665727B; CN102665727A; JP5722233B2

Abstract

Disclosed is an anti-cancer agent characterized by comprising at least one phosphine transition metal complex selected from compounds respectively represented by formulae (1a) to (1c). The anti-cancer agent has an equivalent anti-cancer activity to those of conventional anti-cancer agents and has low toxicity. [In the formulae, R¹ and R² independently represent a linear or branched alkyl group, a cycloalkyl group, a cyclcoalkyl group having a substituent, an adamantyl group, a phenyl group, or a phenyl group having a substituent, wherein each of R¹ and R² has 1 to 10 carbon atoms, R¹ and R² are different from each other, and R¹ has a higher priority than R² as ranked in accordance with the RS system; R³ and R⁴ independently represent a hydrogen atom, or a linear or branched alkyl group, wherein each of R³ and R⁴ has 1 to 6 carbon atoms, R³ and R⁴ may be the same as or different from each other, R³ and R⁴ may together form a saturated or unsaturated ring that may have a substituent; M represents a transition metal atom selected from the group consisting of gold, copper and silver; and X^- represents an anion.]

Description

Anti-cancer agent

The present invention relates to an anticancer agent containing a phosphine transition metal complex.

The present applicant has previously proposed an anticancer agent containing a phosphine transition metal complex represented by the following formula (1 ′) (see Patent Document 1). In the formula, R ¹ , R ² , R ³ and R ⁴ are alkyl groups and the like. M is gold, copper or silver. This anticancer agent has a high anticancer activity as compared with platinum preparations such as cisplatin and Taxol (registered trademark), which are conventionally used anticancer agents.

Since the above phosphine transition metal complex has four asymmetric phosphorus atoms, there are many isomers. Patent Document 1 describes that the types of these isomers are not particularly limited, and the stereo on the phosphorus atom is, for example, (R, R) (R, R) or (S, S) (S, It may be composed of a single enantiomer, such as (S), or may be composed of a racemate of a ligand, such as (R, R) (S, S), and (R). , S) (S, R) may be composed of meso form each other, and (R, R) (S, R) is composed of one enantiomer and its meso form. It is also described as good.

JP 2007-320909 A

Generally, it is known that the anticancer activity and anticancer spectrum of a compound depend on the chemical structure of the compound, and the effect varies depending on the individual. For example, Taxol (registered trademark) described above is known as a highly active anticancer agent, and its effectiveness is about 30%. Therefore, development of various new anticancer agents having different chemical structures is desired. In addition to high anticancer activity, low toxicity is a characteristic required for anticancer agents.

In view of the above-mentioned present situation, the subject of the present invention is to improve the above-mentioned anticancer agent proposed by the present applicant.

The present invention provides an anticancer agent comprising at least one phosphine transition metal complex selected from the group of compounds represented by formulas (1a) to (1c). .

The present invention also provides an anticancer agent comprising a phosphine transition metal complex represented by the formula (2).

According to the present invention, an anticancer agent having an anticancer activity equivalent to that of the prior art and having low toxicity is provided.

The anticancer agent of the present invention contains at least one phosphine transition metal complex selected from the group of compounds represented by the above formulas (1a) to (1c). This phosphine transition metal complex has a structure in which two ligands made of a 2,3-bisphosphinopyrazine derivative are coordinated with a central metal ion M. In the 2,3-bisphosphinopyrazine derivative, R ¹ and R ² are different groups, so that two phosphorus atoms become chiral centers. As a result, this 2,3-bisphosphinopyrazine derivative has three types of isomers, (R, R), (S, S) and (R, S), which have different steric configurations. Therefore, the compounds represented by the formulas (1a) to (1c) are isomers having different steric configurations. As described above in the section of the background art, the phosphine transition metal complex represented by (1 ′) including the formulas (1a) to (1c) contains many isomers having different configurations. As a result of intensive studies by the inventors, among these isomers, by using the compounds represented by the formulas (1a) to (1c), an anticancer equivalent to the anticancer agent described in Patent Document 1 is used. It has been found that an anticancer agent having activity and low toxicity can be obtained.

Although the reason why the compounds represented by the formulas (1a) to (1c) are low in toxicity has not been fully clarified, the anticancer activity and anticancer spectrum of anticancer agents are not effective. The present inventors think that it is because it depends largely on the chemical structure of the adhesive. For example, although the compound represented by the following (1a ′) is included in the compound represented by the compound (1 ′) described in Patent Document 1, this compound (1a ′) has relatively high toxicity. This has been found as a result of the study by the present inventors (see Comparative Example 1 described later).

The compounds represented by the above formulas (1a) to (1c) may be used alone or in combination of two or more. As a result of studies by the present inventors, the compounds represented by the formulas (1a) to (1c) can be used in combination of two or more, rather than using them alone, to further reduce the toxicity. From this point, it turned out to be advantageous. In particular, it has been found that using all the compounds represented by formulas (1a) to (1c) in combination significantly reduces toxicity while maintaining high anticancer activity.

When the compounds represented by the formulas (1a) to (1c) are used in combination, the compounding ratio (molar ratio) of the two compounds is 25/75 to 75 / 25, particularly 40/60 to 60/40. Toxicity can be further reduced by using a combination of two compounds within this molar ratio.

When all the compounds represented by the above formulas (1a) to (1c) are used in combination, the mixing ratio (molar ratio) among these three components is not particularly critical. For example, (1a) :( 1b) :( 1c) = 10 to 40:20 to 80:10 to 40, particularly 20 to 30:40 to 60:20 to 30. Toxicity can be further reduced by using a combination of three compounds within this molar ratio. The current HPLC technique cannot separate the compounds represented by the formulas (1a) to (1c), but according to the production method described later, the product contains the compounds represented by the formulas (1a) to (1a) to (1a) to (1c). It is considered that the compound represented by the formula (1c) is contained in the above molar ratio.

In the anticancer agent of the present invention, a phosphine transition metal complex represented by the above formula (2) may be contained instead of the compounds represented by the above formulas (1a) to (1c). . The compound represented by the formula (2) also has an anticancer activity equivalent to that of the anticancer agent described in Patent Document 1, like the compounds represented by the formulas (1a) to (1c). , Low toxicity.

Furthermore, in the anticancer agent of the present invention, the compounds represented by the above formulas (1a) to (1c) and the compound represented by the above formula (2) may be used in combination. By using a combination of both, toxicity can be further reduced while maintaining high anticancer activity. When both are used in combination, the compounding ratio (molar ratio) between the total amount of the compounds represented by the formulas (1a) to (1c) and the compound represented by the formula (2) is effective even if the ratio is arbitrary. Therefore, the mixing ratio of the former / the latter may be arbitrary, and the ratio of 20/80 to 70/30 is particularly preferable because the synergistic effect becomes high. In this case, as the compounds represented by the formulas (1a) to (1c), only one of them may be used, or any two may be used in combination. Furthermore, you may use combining all 3 types, Formula (1a), Formula (1b), and Formula (1c).

In the above formulas (1a) to (1c) and the above formula (2), R ¹ and R ² are each a linear or branched alkyl group, a cycloalkyl group, a cycloalkyl group having a substituent, An adamantyl group, a phenyl group or a phenyl group having a substituent is shown. R ¹ and R ² have 1 to 10 carbon atoms. R ¹ and R ² are groups different from each other. Furthermore, R ¹ and R ^2, in ranking according to the RS method, R ¹ is priority than R ² is a high group.

Examples of the alkyl group related to R ¹ and R ² include methyl group, ethyl group, isopropyl group, n-propyl group, isobutyl group, n-butyl group, sec-butyl group, tert-butyl group, isoheptyl group, n -Heptyl group, isohexyl group, n-hexyl group. Examples of the cycloalkyl group related to R ¹ and R ² include a cyclopentyl group and a cyclohexyl group. When R ¹ and R ² are a cycloalkyl group having a substituent or a phenyl group having a substituent, examples of the substituent include an alkyl group, a nitro group, an amino group, a hydroxyl group, a fluoro group, a chloro group, and a bromo group. And an iodo group. In particular, it is preferable that R ¹ is a tert-butyl group or an adamantyl group and R ² is a methyl group from the viewpoint of increasing anticancer activity.

R ³ and R ⁴ represent a hydrogen atom or a linear or branched alkyl group. The alkyl group of R ³ and R ⁴ has 1 to 6 carbon atoms. R ³ and R ⁴ may be the same group or different groups. When R ³ and R ⁴ are bonded to each other to form a saturated or unsaturated ring, the saturated or unsaturated ring may have a substituent.

Examples of the alkyl group related to R ³ and R ⁴ include ethyl group, isopropyl group, n-propyl group, isobutyl group, n-butyl group, sec-butyl group, tert-butyl group, isoheptyl group, n-heptyl group, Examples include isohexyl group, n-hexyl group, cyclopentyl group, cyclohexyl group and the like.

When R ³ and R ⁴ are bonded to each other to form a saturated or unsaturated ring, examples of the ring include a saturated or unsaturated 5-membered ring or 6-membered ring. For example, a phenyl group, a cyclohexyl group, a cyclopentyl group, etc. are mentioned. The ring may have a monovalent substituent, and examples of the substituent include a linear or branched alkyl group having 1 to 5 carbon atoms, a nitro group, an amino group, Examples include a hydroxyl group, a fluoro group, a chloro group, a bromo group, and an iodo group.

In particular, R ³ and R ⁴ are preferably bonded to each other to form a benzene ring from the viewpoint of high anticancer activity. In that case, the ligand coordinated to the metal M is a quinoxaline derivative. In the benzene ring in the quinoxaline derivative, at least one of the four hydrogen atoms may be substituted with the above-described substituent.

M represents a monovalent transition metal atom selected from the group consisting of gold, copper and silver. In particular, it is preferable that M is a gold atom from the viewpoint of high anticancer activity.

X ⁻ represents an anion, and examples thereof include chlorine ion, bromine ion, iodine ion, boron tetrafluoride ion, hexafluorophosphate ion, and perchlorate ion. Among these, X ⁻ is preferably a chlorine ion, a bromine ion, or an iodine ion from the viewpoint of high anticancer activity.

Next, the suitable manufacturing method of the phosphine transition metal complex contained in the anticancer agent of this invention is demonstrated. This phosphine transition metal complex can be obtained by reacting a 2,3-bisphosphinopyrazine derivative represented by the formula (3) with a salt of gold, copper or silver.

The 2,3-bisphosphinopyrazine derivative represented by the formula (3) includes, for example, as shown in the reaction formula (9), 2,3-dichloropyrazine (6) and phosphine-borane (7). Reaction is carried out to obtain bis (phosphine-borane) pyrazine (8), and then the resulting bis (phosphine-borane) pyrazine (8) is subjected to a deboraneation reaction.

In the reaction formula (9), the reaction between 2,3-dichloropyrazine (6) and phosphine-borane (7) is carried out, for example, in the presence of a base such as n-butyllithium in an inert solvent such as tetrahydrofuran. The reaction is carried out at −78 to 30 ° C. for 1 to 24 hours.

2,3-dichloropyrazine (6) and phosphine-borane (7) are produced by known methods. 2,3-dichloropyrazine (6) is commercially available. The phosphine-borane (7) can be obtained by using the method described in, for example, JP-A No. 2003-300908, JP-A No. 2001-253889, J. Org. Chem. 2000, vol. 65, P4185-4188, etc. Manufactured.

The deboraneation reaction of bis (phosphine-borane) pyrazine (8) is carried out by adding N, N, N ′, N ′,-tetramethylethylenediamine (TMEDA) to a reaction system containing bis (phosphine-borane) pyrazine (8). And the like, and a reaction is carried out at 0 to 100 ° C. for 10 minutes to 3 hours.

In the 2,3-bisphosphinopyrazine derivative represented by the formula (3), two phosphorus atoms become chiral centers because R ¹ and R ² are different groups. As a result, this 2,3-bisphosphinopyrazine derivative has three types of isomers, (R, R), (S, S) and (R, S), which have different steric configurations. Of these three types of isomers, the (R, S) isomer is a meso isomer, and an equimolar mixture of (R, R) isomer and (S, S) isomer is a racemate. By using these three types of isomers in appropriate amounts, a phosphine transition metal complex having the target steric structure can be obtained.

For example, as a 2,3-bisphosphinopyrazine derivative, by using an (R, S) isomer, that is, a meso isomer, a phosphine transition metal composed of three compounds represented by the formulas (1a) to (1c) A complex is obtained. Moreover, the phosphine transition metal complex which consists of a compound represented by Formula (2) is obtained by using the racemic body of a (R, R) body and a (S, S) body.

(R, S) 2,3-bisphosphinopyrazine derivative can be obtained by the following method. That is, in the above reaction formula (9), a racemate of R and S forms is used as phosphine-borane (7). The resulting 2,3-bisphosphinopyrazine derivative is a mixture of a meso form (ie, (R, S) form) and a racemic form (ie, (R, R) form and (S, S) form). Become. By separating this mixture by chromatography, a meso form (that is, (R, S) form) and a racemic form (that is, (R, R) form and (S, S) form) are separated, and (R, S) The body can be isolated. Racemic, that is, (R, R) and (S, S) isomers are not separated.

Further, the (R, R) isomer of 2,3-bisphosphinopyrazine derivative can be obtained, for example, according to the method described in Example 1 of Japanese Patent Application Laid-Open No. 2007-56007 related to the previous application of the present applicant.

Gold, copper or silver salts that react with the 2,3-bisphosphinopyrazine derivative represented by the formula (3) include, for example, halides, nitrates, perchlorates, and tetrafluoroboric acids of these metals. Salts, hexafluorophosphate and the like. Moreover, the valence of these metals is monovalent. In addition, these metal salts may be two or more salts in which either one or both of the metal and the anion are different.

Preferred gold transition metal salts include, for example, gold chloride (I) acid, gold chloride (I), tetrabutylammonium chloride / gold chloride (I), etc. ("5th edition, Experimental Chemistry Course 21", editors) The Chemical Society of Japan, publisher Maruzen, issue date March 30, 2004, p. 366-380, see Aust. J. Chemm., 1997, 50, pages 775-778). Preferred transition metal salts of copper include, for example, copper chloride (I), copper bromide (I), copper iodide (I), etc. ("5th edition, Experimental Chemistry Course 21", edited by The Chemical Society of Japan, published by the Chemical Society of Japan) Maruzen, issue date, March 30, 2004, p349-361). Preferred silver transition metal salts include, for example, silver chloride (I), silver bromide (I), silver iodide (I), etc. (“5th edition, Experimental Chemistry Course 21”, editor, The Chemical Society of Japan). Issue place Maruzen, issue date March 30, 2004, pages 361-366). The transition metal salt according to the method for producing a phosphine transition metal complex of the present invention may be an anhydride or a hydrate.

The molar ratio of the 2,3-bisphosphinopyrazine derivative represented by the formula (3) to the gold, copper or silver salt is preferably 1 to 5 times mol, more preferably 1.8 to 2.2 times mol. And The reaction can be carried out in a solvent such as acetone, acetonitrile, methanol, ethanol, tetrahydrofuran, dichloromethane, chloroform and the like. The reaction temperature is preferably −20 to 60 ° C., more preferably 0 to 25 ° C., and the reaction time is preferably 0.5 to 48 hours, more preferably 1 to 3 hours. By this reaction, a phosphine transition metal complex represented by formula (1a) to formula (1c) or formula (2) is obtained. After completion of the reaction, conventional purification can be performed as necessary.

The anions in the phosphine transition metal complexes represented by the formulas (1a) to (1c) or (2) thus obtained may be converted into other desired anions. For example, first, a phosphine transition metal complex in which X ⁻ in formula (1a) to formula (1c) or formula (2) is a halide ion is synthesized according to the above production method, and then this phosphine transition metal complex is synthesized. And an inorganic acid, organic acid or alkali metal salt thereof having a desired anion in an appropriate solvent, a phosphine transition metal complex in which X ⁻ is a desired anion can be obtained. Details of such a method are described in, for example, JP-A-10-147590, JP-A-10-114782, and JP-A-61-15944.

The phosphine transition metal complex thus obtained is used as an anticancer agent. The type of cancer to which the anticancer agent of the present invention is applied is not particularly limited. For example, malignant melanoma, malignant lymphoma, digestive organ cancer, lung cancer, esophageal cancer, stomach cancer, colon cancer, rectal cancer. , Colon cancer, ureteral tumor, gallbladder cancer, bile duct cancer, biliary tract cancer, breast cancer, liver cancer, pancreatic cancer, testicular cancer, maxillary cancer, tongue cancer, lip cancer, oral cancer, pharyngeal cancer, laryngeal cancer, ovarian cancer, uterus Cancer, prostate cancer, thyroid cancer, brain tumor, Kaposi's sarcoma, hemangioma, leukemia, polycythemia vera, neuroblastoma, retinoblastoma, myeloma, cystoma, sarcoma, osteosarcoma, myoma, skin cancer, basal cell Cancer, skin appendage cancer, skin metastatic cancer, cutaneous melanoma and the like can be mentioned. Furthermore, it can be applied not only to malignant tumors but also to benign tumors. In addition, the anticancer agent of the present invention can be used to suppress cancer metastasis, and is particularly useful as a postoperative cancer metastasis inhibitor.

The anticancer agent of the present invention can be used in combination with a cyclodextrin compound in order to improve solubility. Examples of the cyclodextrin compound include α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, methyl-β-cyclodextrin, dimethyl-β-cyclodextrin, trimethyl-β-cyclodextrin, and 2-hydroxypropyl-β. -Cyclodextrin, 2-hydroxypropyl-α-cyclodextrin, dihydroxypropyl-β-cyclodextrin, hydroxyethyl-β-cyclodextrin, carboxymethyl-β-cyclodextrin, monoacetyl-β-cyclodextrin, 2-hydroxypropyl -Γ-cyclodextrin, glucosyl-β-cyclodextrin, maltosyl-α-cyclodextrin, maltosyl-β-cyclodextrin, partial methyl-β-cyclodextri , Α-cyclodextrin sulfate, β-cyclodextrin sulfate and the like.

In the use of the anticancer agent of the present invention, the anticancer agent of the present invention can be administered to humans or animals in various forms. The administration form may be oral administration, or parenteral administration such as intravenous, intramuscular, subcutaneous or intradermal injection, rectal administration, transmucosal administration and the like. Examples of the dosage form suitable for oral administration include tablets, pills, granules, powders, capsules, solutions, suspensions, emulsions, syrups and the like. Examples of pharmaceutical compositions suitable for parenteral administration include injections, drops, nasal drops, sprays, inhalants, suppositories, ointments, creams, powdered coatings, liquid coatings, patches, etc. And the like. Furthermore, examples of the dosage form of the anticancer agent of the present invention include an embedding pellet and a sustained-release preparation using a known technique.

Among the above, preferred administration forms, preparation forms, and the like are appropriately selected by a doctor according to the age, sex, constitution, symptoms, treatment timing, etc. of the patient.

When the anticancer agent of the present invention is a solid preparation such as a tablet, pill, powder, powder, granule or the like, these solid preparations are represented by formula (1a) to formula (1c) or formula (2). The phosphine transition metal complex is converted into a suitable additive according to a conventional method, for example, lactose, sucrose, D-mannitol, corn starch, synthetic or natural gum, excipient such as crystalline cellulose, starch, hydroxypropylcellulose, hydroxypropylmethylcellulose , Binders such as gum arabic, gelatin, polyvinyl pyrrolidone, carboxymethyl cellulose calcium, sodium carboxymethyl cellulose, starch, corn starch, disintegrating agents such as sodium alginate, lubricants such as talc, magnesium stearate, sodium stearate, calcium carbonate, Sodium carbonate, phosphorus Calcium, is prepared by mixing as appropriate with such fillers or diluents sodium phosphate. Tablets and the like may be subjected to sugar coating, gelatin, enteric coating, film coating, and the like, if necessary, using a coating agent such as hydroxypropylmethylcellulose, sucrose, polyethylene glycol, and titanium oxide.

When the anticancer agent of the present invention is a liquid preparation such as injection, eye drop, nasal drop, inhalant, spray, lotion, syrup, liquid, suspension, emulsion, etc., these liquid preparations Is a phosphine transition metal complex represented by formula (1a) to formula (1c) or formula (2), purified water, a suitable buffer solution such as phosphate buffer, physiological saline, Ringer's solution, lock solution Such as cocoa butter, cocoa butter, sesame oil, olive oil and other vegetable oils, mineral oil, higher alcohols, higher fatty acids, ethanol and other organic solvents, etc. Suspending agents, dispersion aids, wetting agents, surfactants such as polyoxyethylene hydrogenated castor oil and polyethylene glycols, solubilizing agents such as sodium phosphate, stabilizers such as sugars, sugar alcohols and albumins, parabens Preservatives, isotonic agents such as sodium chloride, glucose, glycerin, buffers, soothing agents, anti-adsorption agents, moisturizers, antioxidants, coloring agents, sweeteners, flavors, aromatic substances, etc. As a result, it is prepared as a sterilized aqueous solution, non-aqueous solution, suspension, liposome, emulsion or the like. At this time, the injection preferably has a physiological pH, and particularly preferably has a pH within the range of 6-8.

When the anticancer agent of the present invention is a semi-solid preparation such as a lotion, cream or ointment, these semi-solid preparations contain a phosphine transition metal complex represented by the general formula (1) as a fat or fatty oil. , Lanolin, petrolatum, paraffin, wax, plaster, resin, plastic, glycols, higher alcohol, glycerin, water, emulsifier, suspending agent and the like.

The content of the phosphine transition metal complex represented by the formula (1a) to the formula (1c) or the formula (2) in the anticancer agent of the present invention depends on the dosage form, the severity, the intended dose, etc. In general, the ratio of the total amount of the phosphine transition metal complex represented by the formula (1a) to the formula (1c) or the formula (2) to the total mass of the anticancer agent is preferably 0. 0.001 to 80% by mass, more preferably 0.1 to 50% by mass.

The dose of the anticancer agent of the present invention is appropriately determined by a doctor according to conditions such as the age, sex, weight, symptom, and administration route of the patient. The amount of the active ingredient per unit is in the range of about 1 μg / kg to 1,000 mg / kg, preferably in the range of about 10 μg / kg to 10 mg / kg. Within this dose range, the anticancer agent can be administered once a day, or can be administered in several divided doses (for example, about 2 to 4 times).

In the use of the anticancer agent of the present invention, it can be combined with known chemotherapy, surgical treatment, radiation therapy, hyperthermia, immunotherapy and the like.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such examples. Unless otherwise specified, “%” means “% by weight”.

[Example 1]
(1) <Synthesis of racemic meso-mixed-2,3-bis (tert-butylmethylphosphino) quinoxaline>
To a 1 L four-necked flask that had been sufficiently removed of water and replaced with nitrogen gas, 84.2 g (750 mmol) of potassium tert-butoxide and 375 ml of dehydrated THF were added. This was cooled to 0 ° C. in an ice bath, and 177.0 g (900 mmol) of a 60% THF solution of racemic tert-butylmethylphosphine borane was added dropwise and stirred for 30 minutes. To another 3 L four-necked flask after sufficiently removing water and replacing with nitrogen gas, 59.7 g (300 mmol) of 2,3-dichloroquinoxaline, 300 ml of dehydrated THF and 75 ml of dehydrated DMF were added to reach −10 ° C. The synthesize | combined phosphine borane solution was dripped here and it stirred for 1 hour. Subsequently, 139.4 g (1200 mmol) of tetramethylethylenediamine was added and the mixture was returned to room temperature and stirred for 3 hours. 600 g of 10% hydrochloric acid was added dropwise for quenching and liquid separation, followed by washing with 150 g of 5% hydrochloric acid and 300 g of 2.5% aqueous sodium bicarbonate. Furthermore, 200 ml of hexane was added and washed with 150 ml of pure water. After the obtained organic layer was dried, 300 ml of methanol was added at 40 ° C. and stirred for 1 hour, and the generated solid was filtered to obtain an orange solid 2,3-bis (tert-butylmethylphosphino) quinoxaline. 69.9 g was obtained (yield 69.7%). The identification data is as follows.
³¹ P-NMR (CDCl ₃ ); racemate: −18.1, meso form: −15.4
HPLC (column Cosmosil 5C18-MS-II 4.6 × 250 mm, moving bed methanol, flow rate 0.5 ml / min, temperature 30 ° C., UV 254 nm, elution time racemate 15 minutes, meso form 17 minutes) racemate: meso Body molar ratio = 52: 48

The mixture of the racemic body and the meso body thus obtained was separated by column chromatography (hexane: ethyl acetate = 200: 1). This separation gave meso form (R, S) -2,3-bis (tert-butylmethylphosphino) quinoxaline.

(2) <Synthesis of bis (2,3-bis (tert-butylmethylphosphino) quinoxaline) gold (I) chloride>
To a 500 ml two-necked flask purged with nitrogen gas, 5.50 g (16.4 mmol) of (R, S) -2,3-bis (tert-butylmethylphosphino) quinoxaline obtained by the above method was added to 220 ml of general THF. Dissolved in. Tetrabutylammonium gold dichloride (4.19 g, 8.2 mmol) was added thereto, and the mixture was stirred at room temperature for 5 hours. The resulting brown precipitate was filtered off, then dissolved in 42 ml of dichloromethane, washed with 50 ml of water, and further dried over sodium sulfate. After filtering this, the solution was dried. This solid was dissolved in 50 ml of dichloromethane, 270 ml of diethyl ether was added and the mixture was heated to 0 ° C., whereupon the solid was precipitated, and 6.60 g of bis (2,3-bis (tert-butylmethylphosphino) quinoxaline) gold (I) chloride. (Yield 89.2%) was obtained. This compound was comprised from the mixture of the compound represented by Formula (1a), Formula (1b), and Formula (1c).
³¹ P-NMR (CDCl ₃ ); 8.5-9.6 (m), 11.6-12.6 (m)

[Example 2]
(1) Racemic of <(R, R) -2,3-bis (tert-butylmethylphosphino) quinoxaline and (S, S) -2,3-bis (tert-butylmethylphosphino) quinoxaline Synthesis>
In (1) of Example 1, (R, R) -2,3-bis (tert-butylmethylphosphino) quinoxaline and (S, S) -2,3 were separated by a step of separating the meso form and the racemic form. A racemate with -bis (tert-butylmethylphosphino) quinoxaline was obtained.

(2) <Synthesis of bis (2,3-bis (tert-butylmethylphosphino) quinoxaline) gold (I) chloride>
Except for using a racemate of (R, R) -2,3-bis (tert-butylmethylphosphino) quinoxaline and (S, S) -2,3-bis (tert-butylmethylphosphino) quinoxaline, Bis (2,3-bis (tert-butylmethylphosphino) quinoxaline) gold (I) chloride was obtained in the same manner as in the step (2) of Example 1. This compound was comprised from the compound represented by Formula (2).
³¹ P-NMR (CDCl ₃ ); 10.2

[Comparative Example 1]
(1) <Synthesis of (R, R) -2,3-bis (tert-butylmethylphosphino) quinoxaline>
(R, R) -2,3-bis (tert-butylmethylphosphino) quinoxaline was obtained according to the description of Example 1 in Japanese Patent Application Laid-Open No. 2007-56007 related to the applicant's previous application.

(2) <Synthesis of bis (2,3-bis (tert-butylmethylphosphino) quinoxaline) gold (I) chloride>
Except for the use of (R, R) -2,3-bis (tert-butylmethylphosphino) quinoxaline, bis (2,3-bis (tert-butyl) was obtained in the same manner as in step (2) of Example 1. Methylphosphino) quinoxaline) gold (I) chloride was obtained. This compound was composed of a compound represented by the formula (1a ′).
³¹ P-NMR (CDCl ₃ ); 13.6
[Α] ^D = +195.3 (c = 0.5, methanol, 25 ° C.)

[Evaluation]
Toxicity tests were conducted when the phosphine transition metal complexes obtained in Examples and Comparative Examples were orally administered to mice. Specifically, after male and female KM mice were quarantined and acclimatized for about 1 week, 10 rats and 10 female rats were selected to make a group. Groups in which the body weight fasted overnight prior to administration recorded corn oil as a solvent, and the phosphine transition metal complexes obtained in Examples and Comparative Examples had enough deaths to determine LD ₅₀ A single oral dose was set up to be included. After administration, it was observed for 10, 30 minutes, 1, 2, 4 hours and every day thereafter until the 14th day, and the 50% lethal dose (LD ₅₀ ) was determined from the survival rate of the rats. The results are shown in Table 1 below.

Moreover, the in vitro antitumor activity test was done about the phosphine transition metal complex obtained by the Example and the comparative example. Specifically, using KB (oral squamous cell carcinoma) and A375 (malignant melanoma) as cancer cells, 10% inactivated neonatal calf serum, L-glutamine, sodium pyruvate, 1 × 10 ⁵ U / L The cells were cultured at 37 ° C. in an incubator in a medium supplemented with penicillin and 100 mg / L streptomycin (RPMI-1640 or DEME). Cells were added at 2 × 10 ⁵ per well. Next, a phosphine transition metal complex solution dissolved in dimethyl sulfoxide was added and incubated for 48 hours. After culturing for 48 hours, 20 μl of a 5 mg / ml (3, [4,5-dimethylthiazol-2-yl] -2,5-diphenyltetrazolium bromide, MTT) solution was added per well and cultured in an incubator for 3 to 4 hours. did. Further, 100 μl of the lysate per well was added to completely solubilize the produced formazan crystals. Then, the absorbance at 492 nm was measured to calculate IC ₅₀ . As a result, in both Examples and Comparative Examples, the IC ₅₀ value was about 1.25 μg / ml, and there was no significant difference.

From the above results, it can be seen that the anticancer agent containing the phosphine transition metal complex of the present invention has low antitoxicity while having anticancer activity equivalent to the conventional one.

Claims

An anticancer agent comprising at least one phosphine transition metal complex selected from the group of compounds represented by formulas (1a) to (1c).
The anticancer agent characterized by containing the phosphine transition metal complex represented by Formula (2).
It contains at least one phosphine transition metal complex selected from the group of compounds represented by formulas (1a) to (1c) and a phosphine transition metal complex represented by formula (2). Cancer drug.