WO2011129365A1

WO2011129365A1 - Antitumor agent

Info

Publication number: WO2011129365A1
Application number: PCT/JP2011/059179
Authority: WO
Inventors: 宣彦大原; 一博中對; 大輔間山
Original assignee: 日本化学工業株式会社
Priority date: 2010-04-14
Filing date: 2011-04-13
Publication date: 2011-10-20
Also published as: JPWO2011129365A1; JP5646606B2

Abstract

Disclosed is an antitumor agent which has higher antitumor activity than conventional antitumor agents, while having low toxicity. Specifically disclosed is an antitumor agent which is characterized by containing a phosphine transition metal complex that is represented by general formula (1). In general formula (1), it is preferable that the phosphine ligand is an (S,S)-2,3-bisphosphinoquinoxaline derivative. It is particularly preferable that the phosphine ligand is an (S,S)-2,3-bis(tert-butylmethylphosphino)quinoxaline. (In the formula, R¹ and R² each represents 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 and has 1-10 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 each represents a hydrogen atom, or a linear or branched alkyl group and has 1-6 carbon atoms; R³ and R⁴ may be the same groups or different groups; R³ and R⁴ may combine together to form a saturated or unsaturated ring, and the saturated or unsaturated ring may have a substituent; M represents a transition metal atom that is 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, (S, S) (S, S) or (R, R) (R, R) may be composed of a single enantiomer, and may be composed of a racemic ligand, such as (R, R) (S, S). , 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 characterized by containing a phosphine transition metal complex represented by the following formula (1).

According to the present invention, an anticancer agent having high anticancer activity and low toxicity is provided.

The anticancer agent of the present invention contains a phosphine transition metal complex represented by the above formula (1). 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. Among these three isomers, the ligand contained in the phosphine transition metal complex represented by the formula (1) is an (S, S) isomer of 2,3-bisphosphinopyrazine derivative. On the other hand, the ligand contained in the phosphine transition metal complex specifically described in Patent Document 1 described in the background art section above is an (R, R) isomer of 2,3- Bisphosphinopyrazine derivative. As a result of intensive studies by the present inventors, an anticancer agent comprising a phosphine transition metal complex using a (S, S) isomer of a 2,3-bisphosphinopyrazine derivative as a ligand is described in Patent Document 1. It was found to have higher anticancer activity and lower toxicity than other anticancer agents.

The reason why the compound represented by the formula (1) has high anticancer activity and low toxicity has not been fully clarified, but the anticancer activity and anticancer spectrum of anticancer agents are The present inventors consider that it is because it depends largely on the chemical structure of the anticancer agent. 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).

In the above formula (1), R ¹ and R ² are 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. Represents. 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.

R ³ and R ⁴ may be bonded to each other to form a saturated or unsaturated ring. In such a case, the ring includes 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, and the phosphine transition metal complex of the present invention is represented by the following formula (2). In the benzene ring in the quinoxaline derivative, at least one of the four hydrogen atoms may be substituted with a substituent R ⁵ . Specifically, as R ⁵ , the same or different alkyl group, nitro group, amino group, hydroxyl group, fluoro group, chloro group, bromo group, iodo group and the like can be used.

M represents a monovalent ion of a transition metal atom selected from the group consisting of gold, copper and silver. In particular, M is preferably a gold ion 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, a preferred method for producing a phosphine transition metal complex contained in the anticancer agent of the present invention will be described. This phosphine transition metal complex can be obtained by reacting a (S, S) -2,3-bisphosphinopyrazine derivative represented by the following formula (3) with a gold, copper or silver salt. A method for producing the (S, S) -2,3-bisphosphinopyrazine derivative represented by the formula (3) will be described later.

Specific examples of preferred compounds of the (S, S) -2,3-bisphosphinopyrazine derivative represented by the formula (3) include (S, S) -2,3-bis (tert-butylmethylphosphino ) Quinoxaline, (S, S) -2,3-bis (adamantylmethylphosphino) quinoxaline, (S, S) -2,3-bis (tert-butylmethylphosphino) pyrazine and the like.

Gold, copper or silver salts that react with the (S, S) -2,3-bisphosphinopyrazine derivative represented by the formula (3) include, for example, halides, nitrates, and perchlorates of these metals. , Tetrafluoroborates, hexafluorophosphates 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 salts include, for example, gold chloride (I) acid, gold chloride (I), or tetrabutylammonium chloride / gold chloride (I) (“5th edition, Experimental Chemistry Course 21”, editor Nihon Kagaku) Society, issue place 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 (S, S) -2,3-bisphosphinopyrazine derivative represented by the formula (3) to the gold, copper, or silver salt is preferably 1 to 5 times moles per mole of metal. More preferably, the molar amount is 1.8 to 2.2 times. 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 the formula (1) is obtained. After completion of the reaction, conventional purification can be performed as necessary.

The anion in the phosphine transition metal complex represented by the formula (1) thus obtained may be converted into another desired anion. For example, first, a phosphine transition metal complex in which X ⁻ in formula (1) is a halide ion is synthesized according to the production method described above, and then the phosphine transition metal complex and an inorganic acid having a desired anion, A phosphine transition metal complex in which X ⁻ is a desired anion can be obtained by reacting an organic acid or an alkali metal salt thereof in a suitable solvent. 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 contain a phosphine transition metal complex represented by the formula (1) according to a conventional method. Suitable additives such as lactose, sucrose, D-mannitol, corn starch, synthetic or natural gums, excipients such as crystalline cellulose, starch, hydroxypropylcellulose, hydroxypropylmethylcellulose, gum arabic, gelatin, polyvinylpyrrolidone, etc. Binders, disintegrants such as calcium carboxymethyl cellulose, sodium carboxymethyl cellulose, starch, corn starch, sodium alginate, lubricants such as talc, magnesium stearate, sodium stearate, calcium carbonate, sodium carbonate, calcium phosphate, sodium phosphate They are prepared by mixing as appropriate with fillers or diluents such as beam. 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 the formula (1), purified water, a suitable buffer solution such as phosphate buffer, physiological saline solution such as physiological saline, Ringer's solution, lock solution, cocoa butter, It dissolves in vegetable oils such as sesame oil and olive oil, mineral oil, higher alcohols, higher fatty acids, organic solvents such as ethanol, etc., if necessary, emulsifiers such as cholesterol, suspension agents such as gum arabic, dispersion aids, wetting agents, Polyoxyethylene hydrogenated castor oil-based, polyethylene glycol-based surfactants, solubilizers such as sodium phosphate, stabilizers such as sugar, sugar alcohol and albumin, preservatives such as parabens, sodium chloride Sterilized aqueous solution by appropriately adding isotonic agents such as glucose and glycerin, buffers, soothing agents, adsorption inhibitors, moisturizers, antioxidants, colorants, sweeteners, flavors, aromatic substances, etc. It is prepared as a non-aqueous solution, suspension, liposome or emulsion. 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 above formula (1) as a fat, fatty oil, It is produced by mixing with lanolin, petrolatum, paraffin, wax, plaster, resin, plastic, glycols, higher alcohol, glycerin, water, emulsifier, suspending agent and the like as appropriate.

The content of the phosphine transition metal complex represented by the formula (1) in the anticancer agent of the present invention varies depending on the dosage form, severity, target dose, etc., but in general, The ratio of the phosphine transition metal complex represented by the formula (1) to the total mass of the anticancer agent is preferably 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.

Finally, a preferred method for producing the (S, S) -2,3-bisphosphinopyrazine derivative represented by the above-described formula (3) will be described. The compound represented by the formula (3) is preferably produced through the following steps I, II and III.

[Process I]
A hydrogen-phosphine borane compound represented by the following formula (4):

The optically active isocyanate compound represented by the following formula (5) is subjected to a coupling reaction,

After obtaining a phosphine borane compound represented by the following formula (6),

The obtained phosphine borane compound represented by the formula (6) is purified by optical resolution to obtain an optically active phosphine borane compound represented by the following formula (6 ′).

[Process II]
The phosphine borane compound represented by the formula (6 ′) obtained in step I is subjected to a decomposition reaction,
An optically active hydrogen-phosphine borane compound represented by the following formula (4 ′) is obtained.

[Step III]
Reacting the optically active hydrogen-phosphine borane compound represented by the formula (4 ′) obtained in Step II with a 2,3-dihalogenopyrazine represented by the following formula (7):

After obtaining an optically active bis (phosphine-borane) pyrazine compound represented by the following formula (8),

A deboraneation reaction of the bis (phosphine-borane) pyrazine compound represented by the above formula (8) is performed to obtain (S, S) -2,3-bisphosphino represented by the above formula (3). A pyrazine derivative is obtained.

The details of Step I to Step III will be described below.

(1) Regarding Step I In Step I, a hydrogen-phosphine borane compound represented by the formula (4) and an optically active isocyanate compound represented by the formula (5) are mixed in a reaction vessel to carry out a coupling reaction. Make it progress. In that case, it is preferable to promote the reaction by adding a base to the reaction system. By this coupling reaction, a phosphine borane compound represented by the formula (6) is generated. As the hydrogen-phosphine borane compound represented by the formula (4), a mixture of an S form and an R form (for example, a racemate) can be used. When a mixture of an S form and an R form is used as the hydrogen-phosphine borane compound represented by the formula (4), the phosphine borane compound represented by the formula (6) produced by the coupling reaction is an Sp form and an Rp form. (The Sp form means a compound in which the configuration of the asymmetric phosphorus atom is S, and the Rp form means the compound in which the configuration of the asymmetric phosphorus atom is R).

In the coupling reaction, a solvent is appropriately used. As this solvent, a solvent that does not decompose the reaction substrate is used. Specific examples include toluene, hexane, tetrahydrofuran (THF), diethyl ether, dioxane, acetone, ethyl acetate, chlorobenzene, dimethylformamide (DMF), acetonitrile, methanol. , Ethanol, water and the like. Preferably it is toluene or THF.

The amount of the solvent added during the reaction can be appropriately set in consideration of the fluidity of the reaction mixture during the reaction and the effect of the solvent on the reaction.

The amount of raw material charged during the reaction is preferably 0.4 to 1.5 equivalents of the hydrogen-phosphine borane compound represented by the formula (4) based on the optically active isocyanate compound represented by the formula (5). is there.

∙ Addition of a base during the reaction accelerates the reaction. Examples of the base include pyridine, triethylamine, tributylamine, 1,8-diazabicyclo [5.4.0] undecene-7 (DBU), 1,5-diazabicyclo [4.3.0] nonene-5 (DBN), Organic bases such as 4- (N, N-dimethylamino) pyridine (DMAP), inorganic bases such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, n-butyllithium, sec-butyllithium, tert-butyl And organic metals such as lithium, lithium diisopropylamide, isopropylmagnesium chloride, and methylmagnesium bromide. A preferred base is n-butyllithium.

The amount of base charged can be appropriately set according to the required degree of reaction promotion. For example, with respect to the optically active isocyanate compound represented by the formula (5), a base is usually used in an amount of 0.1 mol% to 150 mol%, preferably 1 mol% to 10 mol%. The order in which the raw materials and the base are charged is not particularly critical in the present production method, and can be arbitrarily determined according to workability and the like.

The reaction temperature is usually −80 to 50 ° C., and particularly preferably 0 to 30 ° C. from the viewpoint of promoting the reaction and suppressing side reactions and racemization. The reaction time is usually 1 minute to 24 hours, and 30 minutes to 4 hours is particularly preferable because it is sufficient for the reaction to be completed.

Commercially available products can be used as the hydrogen-phosphine borane compound represented by the formula (4) used in the coupling reaction. Such commercial products are available from, for example, Nippon Chemical Industry Co., Ltd. A commercially available product can also be used as the optically active isocyanate compound represented by the formula (5), and for example, it can be obtained from Tokyo Chemical Industry Co., Ltd.

In the optically active isocyanate compound represented by the formula (5), R ⁶ represents an asymmetric hydrocarbon group or a substituted asymmetric hydrocarbon group. Examples of the asymmetric hydrocarbon group include (S) -1-phenylethyl group, (R) -1-phenylethyl group, (S) -1- (p-toluyl) ethyl group, (R) -1- ( p-toluyl) ethyl group, (S) -1- (1-naphthyl) ethyl group, (R) -1- (1-naphthyl) ethyl group, (S) -1-cyclohexylethyl group, (R) -1 -Cyclohexylethyl group, (S) -2- (4-methylphenyl) -1-phenylethyl group, (R) -2- (4-methylphenyl) -1-phenylethyl group, and the like. Among these, (S) -1-phenylethyl group and (R) -1-phenylethyl group are preferred because they can be used industrially at low cost.

As the substituted asymmetric hydrocarbon group represented by R ⁶ , at least one hydrogen atom of the asymmetric hydrocarbon group has a hydrocarbon group, an alkoxy group, a halogen atom, an amino group, a nitro group, or a protecting group. Examples include a hydrocarbon group substituted with a substituent such as an amino group, or a group in which at least one carbon atom of the asymmetric hydrocarbon group is substituted with a heteroatom such as oxygen, nitrogen, sulfur, or phosphorus.

After the coupling reaction, by-product salts are removed, and among the enantiomers (Sp isomer and Rp isomer) of the phosphine borane compound represented by formula (6) by optical resolution, Rp isomer, that is, formula (6 ′) The represented phosphine borane compound is isolated. The phosphine borane compound represented by the formula (6 ′) has an asymmetric part having an asymmetric part on the phosphorus atom or the phosphorus atom as one point of an asymmetric surface, and an optically active carbamoyl group. It is a diastereomer having dots. For optical resolution, liquid separation washing, crystallization, distillation, sublimation, column chromatography, and the like can be used. From the industrial viewpoint, the preferred optical resolution method is crystallization.

In order to successfully isolate the phosphine borane compound represented by the formula (6 ′) from the enantiomer of the phosphine borane compound represented by the formula (6), the group represented by R ⁶ is appropriately selected. do it. For example, in the formula (6 ′), when R ¹ is a tert-butyl group and R ² is a methyl group, the group represented by R ⁶ is (S) -asymmetric hydrocarbon group or (S) — When a substituted asymmetric hydrocarbon group is used, the phosphine borane compound represented by the formula (6 ′) (that is, the Sp isomer) is preferentially precipitated by crystallization, while the Rp isomer remains in the solution. So both can be separated successfully.

(2) Step II The phosphine borane compound represented by the formula (6 ′) obtained in Step I and a base are mixed in a reaction vessel to decompose the phosphine borane compound. It is preferable to add alcohol to promote the decomposition reaction. After the reaction, the by-product is removed to obtain an optically active hydrogen-phosphine borane compound represented by the formula (4 ′).

In the reaction, a solvent is appropriately used. As this solvent, a solvent that does not decompose the reaction substrate is used. Specific examples include toluene, hexane, tetrahydrofuran (THF), diethyl ether, dioxane, acetone, ethyl acetate, chlorobenzene, dimethylformamide (DMF), acetonitrile, methanol. , Ethanol, water and the like. It is particularly preferable to use DMF or acetonitrile.

Examples of the base include pyridine, triethylamine, tributylamine, 1,8-diazabicyclo [5.4.0] undecene-7 (DBU), 1,5-diazabicyclo [4.3.0] nonene-5 (DBN). ), 4- (N, N-dimethylamino) pyridine (DMAP) and the like, and inorganic bases such as sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate. In order to carry out the reaction in a homogeneous system or a liquid-liquid two-phase system, the base is preferably supplied as a solution. For example, when potassium hydroxide is used as the base, it is preferably a 1 to 70% by mass aqueous solution or a methanol solution, for example.

The amount of base charged can be appropriately set according to the required degree of reaction promotion. For example, with respect to the phosphine borane compound represented by the formula (6 '), a base can usually be added in an amount of 0.01 equivalent to 10 equivalents, particularly preferably 0.1 equivalent to 5 equivalents. The order in which the phosphine borane compound represented by formula (6 ') and the base are charged is not particularly critical in this production method, and can be arbitrarily determined according to workability and the like.

For the purpose of promoting the reaction, it is preferable to add alcohol as described above. For example, methanol or ethanol can be used as the alcohol, and methanol is particularly preferable.

The reaction temperature is usually −80 to 50 ° C., and particularly preferably 0 to 30 ° C. from the viewpoint of promoting the reaction and suppressing side reactions and racemization. The reaction time is usually 1 minute to 24 hours, and 3 hours to 20 hours is particularly preferable because it is sufficient for the reaction to be completed.

After the reaction, the obtained product can be subjected to Step III after a simple purification operation such as only removal of by-product salts. Alternatively, after isolating only the optically active hydrogen-phosphine borane compound represented by the formula (4 ′) by a purification operation such as liquid separation washing, crystallization, distillation, sublimation, and column chromatography, Can also be provided.

(3) Step III In the compound represented by the formula (7) used in this step, examples of the halogen atom represented by X include fluorine, chlorine, bromine and iodine.

As the 2,3-dihalogenopyrazine derivative represented by the formula (7), for example, a commercially available product can be used. Examples of such commercially available products include 2,3-dichloroquinoxaline, which is a compound available from Tokyo Chemical Industry Co., Ltd.

In step III, the reaction between the optically active hydrogen-phosphine borane compound represented by formula (4 ′) obtained in step II and the 2,3-dihalogenopyrazine derivative represented by formula (7) is as follows: For example, the reaction is carried out in the presence of a base in an inert solvent at −78 to 30 ° C. for 1 to 24 hours. By this reaction, a bis (phosphine-borane) pyrazine compound represented by the formula (8) is obtained.

The amount of raw materials charged during the reaction is preferably an optically active hydrogen-phosphine borane compound represented by the formula (4 ′) based on the 2,3-dihalogenopyrazine derivative represented by the formula (7). ˜10 equivalents, more preferably 2 to 3 equivalents.

Examples of the inert solvent used in this step include tetrahydrofuran, N, N-dimethylformamide, diethyl ether, dibutyl ether, dioxane, hexane, toluene and the like. In particular, it is preferable to use tetrahydrofuran. The addition amount of the inert solvent during the reaction can be appropriately set in consideration of the fluidity of the reaction mixture during the reaction and the effect of the solvent on the reaction.

Examples of the base used in this step include n-butyllithium, methylmagnesium bromide, t-butoxypotassium, potassium hydroxide, sodium hydroxide and the like. In particular, n-butyllithium is preferably used. The amount of base charged can be appropriately set according to the required degree of reaction promotion. For example, with respect to the 2,3-dihalogenopyrazine derivative represented by the formula (7), usually 2 to 10 equivalents of a base can be added, and 2 to 3 equivalents are preferably added. The order in which the respective compounds are charged in this step is not critical, and can be arbitrarily determined according to workability and the like.

For example, the deboraneation reaction of the bis (phosphine-borane) pyrazine compound represented by the formula (8) can be carried out by adding a deboraneation reaction to the reaction system containing the bis (phosphine-borane) pyrazine compound obtained by the above reaction. The agent is added and the reaction is performed at 0 to 100 ° C. for 10 minutes to 3 hours. By this deboraneation reaction, an optically active (S, S) -2,3-bisphosphinopyrazine derivative represented by the formula (3), which is the target product, is obtained.

Examples of the deboronating agent include N, N, N ′, N ′,-tetramethylethylenediamine (TMEDA), triethylenediamine (DABCO), triethylamine and the like. It is particularly preferable to use TMEDA. The amount of the deboronating agent charged relative to the 2,3-dihalogenopyrazine derivative represented by the formula (7) used in obtaining the bis (phosphine-borane) pyrazine compound represented by the formula (8) is as follows. The amount is usually 2 to 20 equivalents, preferably 2 to 10 equivalents.

The optically active (S, S) -2,3-bisphosphinopyrazine derivative represented by the formula (3) produced by the deboraneation reaction may be subjected to liquid separation washing, crystallization, distillation, sublimation, It may be subjected to purification work such as column chromatography.

Hereinafter, the present invention will be specifically described with reference to examples. However, such examples are merely examples, and the scope of application of the present invention is not limited thereto.

All synthesis operations were performed using well-dried glass containers. The reaction was performed under a nitrogen atmosphere. General reagents were used as the raw material reagent and the solvent. Racemic tert-butylmethylphosphine borane manufactured by Nippon Chemical Industry Co., Ltd. was used.

NMR spectrum measurement was performed with a JEOL ( ¹ H; 300 MHz, ¹³ C; 75.4 MHz, ³¹ P; 121.4 MHz) NMR apparatus. Tetramethylsilane ( ¹ H) was used as an internal standard. The specific rotation was measured with a specific rotation meter SEPA-300 manufactured by Horiba.

[Example 1]
<Step I> Production of (S _P ) -tert-butyl (methyl) [N-((S) -1-phenylethyl) carbamoyl] phosphine-borane Into a 3 L four-necked flask, a mechanical stirring seal, a thermometer, etc. A pressure dropping funnel and an exhaust part were provided. Thereto, 141.8 g (1202 mmol) of racemic-tert-butylmethylphosphine borane and 600 cc of THF were added, and the racemic-tert-butylmethylphosphine borane was dissolved, and 1.59 mol / L of n-butyl was maintained at 10 ° C. or lower. 75 cc (119 mmol) of a lithium-hexane solution was added dropwise. Subsequently, 176.8 g (1201 mmol) of (S)-(−)-α-methylbenzyl isocyanate was added dropwise at the same temperature. Thereafter, the temperature was returned to room temperature and aged with stirring overnight. The reaction was stopped by adding 90 g of 5% by weight hydrochloric acid, and then 240 cc of hexane and 240 cc of water were added to separate into two layers. The aqueous layer was removed, and the organic layer was washed with 240 g of 2.5% by weight aqueous sodium bicarbonate followed by 240 cc of water and concentrated to give a crude product (white flaky solid) as a phosphine borane represented by the general formula (3). Compound was obtained (348.3 g). The crude product was crystallized with 240 cc of ethyl acetate and 1800 cc of hexane, filtered and dried to obtain a colorless powder. The colorless powder obtained was identified as the title compound by NMR analysis. The NMR analysis results are shown below. The obtained colorless powder had a yield of 118.6 g (447 mmol), a yield of 37% (from isocyanate), and a diastereomeric excess> 97% de. The diastereomeric excess was determined from the area ratio of specific part protons of SP and RP of ¹ H-NMR.

(NMR analysis result)
¹ H-NMR (CDCl ₃ );
(S _P ) -body (target); -0.5-1 (3H, m), 1.14 (9H, d, 14.7 Hz), 1.45 (3H, d, 10.5 Hz), 1 .53 (3H, d, 6.9 Hz), 5.15 (1 H, pent, 6.9 Hz), 7.2-7.4 (6H, m).
(R _P ) -isomer; -0.5-1 (3H, m), 1.25 (9H, d, 14.7 Hz), 1.42 (3H, d, 10.5 Hz), 1.53 (3H , D, 6.9 Hz), 5.15 (1H, pent, 6.9 Hz), 7.2-7.4 (6H, m).

<Step II> Production of optically active hydrogen-phosphine borane compound [(R) -tert-butylmethylphosphine-borane] A 200 cc four-necked flask was equipped with a mechanical stirring seal, a thermometer, and an exhaust part. (S _P ) -tert-butyl (methyl) [N-((S) -1-phenylethyl) carbamoyl] phosphine-borane obtained in 1) and 100 cc of DMF were added, and phosphine-borane was added. After dissolution, the temperature was adjusted to 10 ° C. or lower in an ice water bath. Thereto were added 21.26 g (189 mmol) of a 50 wt% aqueous potassium hydroxide solution and 25 cc of methanol. Next, the ice-water bath was removed and the mixture was aged with stirring for 18 hours. Next, 100 cc of cold water and 100 cc of petroleum ether were placed in a 500 cc Erlenmeyer flask, and the reaction was stopped by dispersing the reaction solution therein. The aqueous layer and the organic layer were separated, the aqueous layer was re-extracted with 100 cc of petroleum ether, combined with the previously separated organic layer, washed twice with 50 cc of water, and dried over anhydrous sodium sulfate. Purification by silica gel column chromatography (Wakogel C200) gave a colorless powder. The colorless powder obtained was identified as the title compound by NMR analysis. The NMR analysis results are shown below. The obtained colorless powder had a yield of 3.01 g (25.5 mmol) and a yield of 67%.

(NMR analysis result)
¹ H-NMR (CDCl ₃ );
-0.5-1 (3H, m), 1.22 (9 H, d, 14.7 Hz), 1.32 (3 H, dd, 10.5 Hz, 6.0 Hz), 4.4 (1 H, dm, 355 Hz).

<Step III> (S, S) -2,3-bis (tert-butylmethylphosphino) quinoxaline production step II (R) -tert-butylmethylphosphine-borane 3.01 g (25.5 mmol) ) Was dissolved in 25 cc of dehydrated THF in a flask and cooled to -78 ° C. To this was added dropwise 15.5 cc (25.6 mmol) of a 1.65 mol / L n-butyllithium-hexane solution, and the mixture was aged and stirred at the same temperature for 15 minutes. Subsequently, 1,703 mg (8.56 mmol) of 2,3-dichloroquinoxaline was added all at once with good stirring. After the addition, the mixture was returned to room temperature over 1 hour and stirred for 3 hours. Subsequently, 10.07 g (87 mmol) of tetramethylethylenediamine was added, followed by stirring and aging at room temperature (25 ° C.) for 2 hours. The reaction was stopped by adding 1M hydrochloric acid, and hexane was added to extract organic components. The organic layer was washed with 1M hydrochloric acid and then with saturated brine, and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography (hexane / ethyl acetate = 30/1) to obtain the title compound as an orange powder. Further, the crystals were recrystallized and purified from hot methanol to obtain orange cubic crystals. The yield was 2,149 mg (6.427 mmol), and the yield was 75%. The analysis results of the obtained title compound are shown below.

(result of analysis)
¹ H-NMR (CDCl ₃ );
1.02 (18 H, t, 6.0 Hz), 1.4 (6 H, t, 3.2 Hz), 7.68-7.75 (2 H, m), 8.07-8.14 (2 H, m ).
¹³ C-NMR (CDCl ₃ );
4.8 (d), 27.6 (t), 31.9 (t), 129.6 (d), 141.6, 165.1 (d), 165.2 (d).
³¹ P-NMR (CDCl ₃ );
-16.6.
Specific rotation: + 53.5 ° ([α] ^D ₂₂ (c = 1, CHCl ₃ ); (R, R) is known to have a specific rotation of −54.3 °)
Melting point: 102-103 ° C

<Step IV> Synthesis of (R, R, R, R) -bis (2,3-bis (tert-butylmethylphosphino) quinoxaline) gold (I) chloride Into a 500 ml two-necked flask substituted with nitrogen gas, (S, S) -2,3-bis (tert-butylmethylphosphino) quinoxaline 5.50 g (16.4 mmol) obtained by the above method was dissolved in 220 ml of general THF. 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 (R, R, R, R) -bis (2,3-bis (tert-butylmethylphosphino) Quinoxaline) 7.26 g (98% yield) gold (I) chloride was obtained.

(result of analysis)
³¹ P-NMR (CDCl ₃ ); 13.6
-HPLC (column Sumichiral OA-8000 4.6 × 250 mm, moving bed hexane: ethanol: methanol: trifluoroacetic acid = 930: 40: 30: 1, flow rate 1.0 ml / min, temperature 35 ° C., UV 254 nm, elution time ; 49.5 minutes

[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 (S, S, S, S) -bis (2,3-bis (tert-butylmethylphosphino) quinoxaline) gold (I) chloride>
(S, S, S, S) -bis (2,2) is the same as step IV in Example 1 except that (R, R) -2,3-bis (tert-butylmethylphosphino) quinoxaline is used. 3-Bis (tert-butylmethylphosphino) quinoxaline) gold (I) chloride was obtained. This compound is included in the compound represented by the formula (1a ′).
³¹ P-NMR (CDCl ₃ ); 13.6
[Α] ^D = +195.3 (c = 0.5, methanol, 25 ° C.)

[Evaluation]
The phosphine transition metal complexes obtained in Examples and Comparative Examples were subjected to in vitro antitumor activity tests and toxicity tests when orally administered to mice by the following methods. The results are shown in Table 1 below.

[In vitro antitumor activity test]
Moreover, the in vitro antitumor activity test was done about the phosphine transition metal complex obtained by the Example and the comparative example. Specifically, BGC-823 (human gastric adenocarcinoma) was used as a cancer cell, 10% inactivated neonatal calf serum, L-glutamine, sodium pyruvate, 1 × 10 ⁵ U / L penicillin, 100 mg / L streptomycin In a medium supplemented with (RPMI-1640 or DEME) at 37 ° C. in an incubator. 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 .

[Toxicity test]
Toxicity tests were conducted when the phosphine transition metal complexes obtained in Examples and Comparative Examples were intravenously injected into 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 that was fasted overnight before administration was recorded in corn oil as a solvent, and the phosphine transition metal complexes obtained in Examples and Comparative Examples had enough deaths to determine LD ₅₀ Was set up to include a single intravenous injection. 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.

From the results shown in Table 1, it can be seen that the anticancer agent containing the phosphine transition metal complex of the present invention has higher anticancer activity and lower toxicity than before.

Claims

An anticancer agent comprising a phosphine transition metal complex represented by the following formula (1):
The anticancer agent of Claim 1 containing the phosphine transition metal complex represented by the following formula | equation (2).
The manufacturing method of the phosphine transition metal complex represented by the following formula | equation (1) characterized by having the following process I thru | or IV.

[Process I]
A hydrogen-phosphine borane compound represented by the following formula (4):

An optically active isocyanate compound represented by the following formula (5) is subjected to a coupling reaction,

After obtaining a phosphine borane compound represented by the following formula (6),

The obtained phosphine borane compound represented by the formula (6) is purified by optical resolution to obtain an optically active phosphine borane compound represented by the following formula (6 ′).

[Process II]
The phosphine borane compound represented by the formula (6 ′) obtained in step I is subjected to a decomposition reaction,
An optically active hydrogen-phosphine borane compound represented by the following formula (4 ′) is obtained.

[Step III]
Reacting the optically active hydrogen-phosphine borane compound represented by the formula (4 ′) obtained in Step II with a 2,3-dihalogenopyrazine represented by the following formula (7):

After obtaining an optically active bis (phosphine-borane) pyrazine compound represented by the following formula (8),

A deboraneation reaction of the bis (phosphine-borane) pyrazine compound represented by the above formula (8) is performed, and (S, S) -2,3-bisphosphino represented by the following formula (3) is performed. A pyrazine derivative is obtained.

[Process IV]
By reacting the (S, S) -2,3-bisphosphinopyrazine derivative represented by the formula (3) obtained in Step III with a salt of gold, copper or silver, the above formula (1) The phosphine transition metal complex represented is obtained.