JP2011105659A - INDOLO[2,3-b]QUINOXALINE COMPOUND HAVING ERYTHROPOIETIN PRODUCTION-PROMOTING EFFECT - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compound having a low-molecular EPO (erythropoietin) production-promoting effect. <P>SOLUTION: The indolo[2,3-b]quinoxaline compound is represented by formula (1). In the formula, R<SP>1</SP>denotes a hydrogen atom, a C<SB>1-6</SB>alkyl group, a carboxy-C<SB>1-6</SB>alkyl group, a C<SB>2-7</SB>alkoxycarbonyl-C<SB>1-6</SB>alkyl group; R<SP>2</SP>and R<SP>3</SP>each denotes a hydrogen atom or a halogen atom; and R<SP>4</SP>denotes a hydrogen atom, a halogen atom, or a nitro group. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a novel erythropoietin production promoter. More specifically, the present invention relates to a preventive and / or therapeutic agent for diseases caused by decreased production of erythropoietin, such as anemia.

  Erythropoietin (EPO) is a glycoprotein hormone involved in the maturation and differentiation of erythroid progenitor cells into mature erythrocytes, and is a naturally occurring monomeric polypeptide consisting of 165 amino acids (Non-patent Document 1). ).

  Human EPO is essential for the growth and differentiation of erythrocytes and is useful for the treatment of blood diseases characterized by a decrease in erythrocyte production. Clinically, EPO is found in patients with chronic renal failure (CRF) who are treated for anemia, self-contained blood, and premature infant anemia (Non-Patent Documents 2-4), in cancer patients undergoing AIDS and chemotherapy. (Non-patent Document 5). EPO has also been shown to be effective in chronic anemia.

  EPO is produced mainly in the kidney in adults, but it is also produced in astrocytes and neurons in the central nervous system, and EPO and EPO receptors are expressed in capillaries at the brain-periphery boundary. In addition, systemic administration of EPO has been reported to cross the blood brain barrier and reduce neuronal cell loss in response to brain and spinal cord ischemia, mechanical trauma, epilepsy, excitotoxins and neuroinflammation. (Non-Patent Documents 6 to 10).

  In the therapy using a protein such as EPO, in order to maintain a therapeutically effective concentration of the compound in the circulation and a short plasma half-life due to being susceptible to protease degradation (Non-patent Documents 11 and 12) There are problems such as having to make internal injections frequently. In addition, there is subcutaneous injection as an administration route instead of intravenous injection, but since the absorption from the administration site is slow, there is a sustained release effect, but the plasma concentration is significantly lower than that of intravenous injection. Therefore, in order to obtain the same therapeutic effect, the same number of injections as in the case of intravenous injection must be performed, which is a burden on the patient. In addition, human serum EPO is a glycoprotein, and the structure of the sugar chain bound to the surface of EPO is complex, and its glycosylation is extensive and diverse. However, human serum EPO cannot be produced with good reproducibility.

  Therefore, there is a need in the art for methods and compounds that increase endogenous EPO, rather than low bioavailability EPO, in the treatment of diseases caused by reduced EPO production including anemia as described above.

  On the other hand, it is known that the production amount of EPO is controlled by the oxygen concentration via a hypoxia-inducible factor (HIF) that is a transcription factor (Non-patent Document 13). That is, under normal atmospheric conditions, the HIF subunit (HIF-1α) in which the proline residue is hydroxylated by 2-oxoglutarate dioxygenase enzyme is degraded by the ubiquitin-proteasome system, and the production of EPO is not promoted. Below, hydroxylation of the proline residue of HIF-1α by the 2-oxoglutarate dioxygenase enzyme is suppressed, and as a result, the stabilized HIF-1α moves from the cytoplasm into the nucleus and dimerizes with HIF-1β. It forms a body and binds to the hypoxia responsive element (HRE) sequence of the EPO gene to promote transcription and promote production of EPO.

  Enzyme inhibitors for HIF prolyl hydroxylase such as 2-oxoglutarate dioxygenase enzyme utilizing such an EPO production mechanism have been reported as EPO production promoters (Patent Documents 1 to 4).

  However, genes whose production is controlled by HIF include not only genes encoding EPO but also genes encoding vascular endothelial growth factor (VEGF). It has also been reported that VEGF has an angiogenesis-promoting action and can cause malignant tumors to deteriorate through this function (Non-Patent Documents 14 and 15). In addition, since anemia is also caused by cancer chemotherapy, and an anemia treatment drug may be administered to a cancer patient receiving such chemotherapy (Non-patent Document 6), VEGF worsens cancer. Such a risk is included in a compound having an inhibitory action on HIF prolyl hydroxylase enzyme activity that may also promote the production of and the like.

  The production of EPO is controlled by a promoter located on the 5 'side of EPO and an enhancer located on the 3' side, and HIF is considered to bind to the HRE sequence in the enhancer and promote the production of EPO. In addition, GATA-2, NFκB, and the like are also considered to control EPO production (Non-patent Documents 16 and 17), and it is considered that EPO production promotion can be achieved by an action mechanism other than inhibition of HIF prolyl hydroxylase enzyme activity. Therefore, a compound having an EPO production promoting action independent of inhibition of HIF prolyl hydroxylase enzyme activity is considered useful in the treatment of anemia.

  In addition, as described above, EPO promotes proliferation and maturation of erythroid progenitor cells, but a compound having an action of promoting maturation / differentiation of erythroid progenitor cells without involving production of EPO is also a therapeutic agent for anemia. Useful as. Compounds that have an activity to enhance blood cell proliferation promoting action of EPO and compounds that have an inhibitory action on hematopoietic cell phosphatase that catalyzes dephosphorylation, which is one of the important control mechanisms of EPO signaling, have been reported. (Patent Documents 5 to 7), the activity is not always sufficient. Furthermore, although synthetic peptides and hematides that act on the EPO receptor have been reported (Non-patent Document 18), a high dose is required for the expression of activity equivalent to EPO, and it is not suitable for oral administration. There is.

  Therefore, an orally administrable low-molecular-weight anemia treatment agent having an EPO production promoting action is considered useful in future anemia treatment.

  On the other hand, as a compound having a skeleton related to the present invention, a compound having an indolo [2,3-b] quinoxaline skeleton that is effective as a therapeutic agent for autoimmune diseases has been reported (Patent Document 8).

[Wherein, R ¹ is hydrogen, or 1 in 7th to 10th positions selected from a halogen group, a lower alkyl / alkoxy group, a hydroxy group, a trifluoromethyl group, a trichloromethyl group, and a trifluoromethoxy group. One or more similar or different substituents; R ² represents a similar or different C ₁ -C ₄ alkyl substituent; X is CO or CH ₂ ; Y is OH, NH ₂ , NH— (CH ₂ ) _n- R ³ (wherein R ³ represents lower alkyl, OH, NH ₂ , NHR ⁴ or NR ⁵ R ⁶ , in which R ⁴ , R ⁵ and R ⁶ are independently lower alkyl Or n is an integer from 2 to 4; when X is CH ₂ , Y is OH or NH— (CH ₂ ) _n —OH].

And in the said literature, anemia is described as one disease state of an autoimmune disease. However, the compounds of this document, indolo [2,3-b] and at the same time have a C ₁ -C ₄ alkyl group at the 2-position and 3-position on the quinoxaline ring, differ from the compounds of the present invention in this regard. In addition, the examples only describe the evaluation of arthritis models and experimental allergic encephalomyelitis models, and although there are suggestions on the treatment of rheumatism and multiple sclerosis, whether it is effective for the treatment of anemia It is not clear about. Furthermore, there is no description or suggestion regarding the action of promoting the production of erythropoietin as in the present invention.

  Other references include use as an anti-rheumatic agent (Non-Patent Document 19), use as an anticancer agent (Patent Documents 9, 10, and Non-Patent Document 20), use as a therapeutic agent for viral infection (Patent Document 11, Non-Patent Document) Documents 21 to 23). However, in these documents, there is no description or suggestion regarding an effect of promoting anemia treatment or erythropoietin production.

JP 2006-137763 A WO2003 / 53997 pamphlet WO2005 / 11696 pamphlet WO2007 / 38571 pamphlet Special Table 2000-536365 JP-A-11-171774 JP 2002-275159 A Japanese translation of PCT publication No. 2008-502676 WO94 / 24135 pamphlet WO96 / 19996 pamphlet WO96 / 00067 pamphlet

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  An object of the present invention is to provide a compound having a low molecular weight EPO production promoting action. More specifically, the object is to provide a medicament useful for the prevention and / or treatment of anemia.

  In view of the above situation, as a result of intensive search for compounds having an EPO production promoting action, the present inventors have found that an indolo [2,3-b] quinoxaline compound represented by the following general formula (1) is derived from human liver cancer. In the test using HepG2 cells, EPO production was found to be completed, and the present invention was completed.

  That is, the present invention provides the following general formula (1):

[Where:
R ¹ represents a hydrogen atom, a C _1-6 alkyl group, a carboxy-C _1-6 alkyl group, a C _2-7 alkoxycarbonyl-C _1-6 alkyl group,
R ² and R ³ may be the same or different and each represents a hydrogen atom or a halogen atom;
R ⁴ represents a hydrogen atom, a halogen atom or a nitro group]
The EPO production promoter which uses the indolo [2,3-b] quinoxaline compound represented by these, its salt, or those solvates as an active ingredient.

More specifically, the present invention provides the following compound group:
9-bromo-6-methyl-6H-indolo [2,3-b] quinoxaline,
6-ethyl-6H-indolo [2,3-b] quinoxaline,
6-methyl-6H-indolo [2,3-b] quinoxaline,
6-methyl-9-nitro-6H-indolo [2,3-b] quinoxaline,
9-bromo-2,4-dichloro-6H-indolo [2,3-b] quinoxaline,
Ethyl 2- (6H-indolo [2,3-b] quinoxalin-6-yl) acetate,
Methyl 2- (6H-indolo [2,3-b] quinoxalin-6-yl) acetate,
Methyl 2- (9-chloro-6H-indolo [2,3-b] quinoxalin-6-yl) acetate,
2- (6H-indolo [2,3-b] quinoxalin-6-yl) acetic acid,
Methyl 2- (9-methyl-6H-indolo [2,3-b] quinoxalin-6-yl) acetate, and 2- (9-methyl-6H-indolo [2,3-b] quinoxalin-6-yl) The EPO production promoter selected from the group consisting of acetic acid is provided.

  The present invention also relates to an agent for preventing and / or treating anemia comprising an indolo [2,3-b] quinoxaline compound represented by the general formula (1) or a salt thereof, or a solvate thereof as an active ingredient. About. More specifically, the present invention relates to a prophylactic and / or therapeutic agent for anemia comprising an indolo [2,3-b] quinoxaline compound selected from the above compound group, or a salt thereof, or a solvate thereof as an active ingredient. Is to provide.

  The present invention also provides an indolo [2,3-b] quinoxaline compound represented by the above general formula (1), a salt thereof, or a solvate thereof for producing a preparation for promoting EPO production. Concerning use. More specifically, the present invention relates to an indolo [2,3-b] quinoxaline compound selected from the above-mentioned compound group, or a salt thereof, or a solvate thereof for producing a preparation for promoting EPO production. It is intended to provide use.

  Furthermore, the present invention is required to promote the production of EPO with an effective amount of the indolo [2,3-b] quinoxaline compound represented by the general formula (1), or a salt thereof, or a solvate thereof. The present invention relates to a method for promoting EPO production, characterized by being administered to a patient. More specifically, the present invention requires an effective amount of an indolo [2,3-b] quinoxaline compound selected from the group of compounds described above, or a salt thereof, or a solvate thereof to promote production of EPO. A method of promoting EPO production, characterized by being administered to a patient.

  In addition, the present invention provides a method in which an effective amount of an indolo [2,3-b] quinoxaline compound represented by the general formula (1) or a salt thereof, or a solvate thereof is brought into contact with the cell, The present invention relates to a method for promoting the production of EPO. More specifically, the present invention is directed to contacting cells with an effective amount of an indolo [2,3-b] quinoxaline compound selected from the group of compounds described above, or a salt thereof, or a solvate thereof. A method for promoting the production of EPO is provided. Here, the term “contact” as used herein means that the indolo [2,3-b] quinoxaline compound or the like of the present invention has an uptake action or a cell surface of the compound or the like by a cell in vitro or in vivo. This means that the compound or the like is added to the cells so as to regulate cell functions such as proliferation, differentiation, secretion of physiologically active substances, etc. by the interaction in

  The present invention has found an indolo [2,3-b] quinoxaline compound, or a salt thereof, or a solvate thereof having an excellent EPO production promoting action, and promotes EPO production. Diseases whose symptoms are ameliorated (e.g., anemia in patients with chronic renal failure, anemia of premature infants, anemia in cancer patients undergoing AIDS and chemotherapy, chronic anemia, iron deficiency anemia, aplastic anemia, It is useful as a pharmaceutical composition for the prevention and / or treatment of hemolytic anemia, anemia such as megaloblastic anemia). The present invention also provides a preventive and / or therapeutic agent for anemia comprising an orally administrable low molecular weight compound having an EPO production promoting action as an active ingredient.

  Hereinafter, the present invention will be described in detail.

  The definitions of terms in the present invention are as follows.

  As used herein, “halogen atom” means a halogeno group, specifically a fluorine atom, a chlorine atom, a bromine atom or an iodine atom.

As used herein, an “alkyl group” may be linear or branched. Therefore, “C _1-6 alkyl group” includes methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, Isopentyl group, neopentyl group, 4-methylbutyl group, 1-ethylpropyl group, n-hexyl group, isohexyl group, 3-methylpentyl group, 2-methylpentyl group, 1-methylpentyl group, 3,3-dimethylbutyl group 2,2-dimethylbutyl group, 1,1-dimethylbutyl group, 1,2-dimethylbutyl group, 1,3-dimethylbutyl group, 2,3-dimethylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group And a straight chain or branched alkyl group having 1 to 6 carbon atoms. Preferably, it is a “C _1-4 alkyl group”.

As used herein, the “carboxy-C _1-6 alkyl group” includes a carboxymethyl group, a 1-carboxyethyl group, a 2-carboxyethyl group, a 1-carboxypropyl group, a 2-carboxypropyl group, 3-carboxypropyl group, 1-carboxybutyl group, 2-carboxybutyl group, 3-carboxybutyl group, 4-carboxybutyl group, 1-carboxypentyl group, 2-carboxypentyl group, 3-carboxypentyl group, 4- Examples include carboxypentyl group, 5-carboxypentyl group, 1-carboxyhexyl group, 2-carboxyhexyl group, 3-carboxyhexyl group, 4-carboxyhexyl group, 5-carboxyhexyl group, 6-carboxyhexyl group and the like. Preferably, it is a “carboxy-C _1-4 alkyl group”.

As used herein, an “alkoxy group” may be linear or branched. Accordingly, the “C _2-7 alkoxycarbonyl-C _1-6 alkyl group” includes methoxycarbonylmethyl group, ethoxycarbonylmethyl group, propoxycarbonylmethyl group, butoxycarbonylmethyl group, pentyloxycarbonylmethyl group, hexyloxycarbonylmethyl. Group, 1- (methoxycarbonyl) ethyl group, 2- (methoxycarbonyl) ethyl group, 1- (methoxycarbonyl) propyl group, 2- (methoxycarbonyl) propyl group, 3- (methoxycarbonyl) propyl group, 1- ( Methoxycarbonyl) butyl group, 2- (methoxycarbonyl) butyl group, 3- (methoxycarbonyl) butyl group, 4- (methoxycarbonyl) butyl group, 1- (methoxycarbonyl) pentyl group, 2- (methoxycarbonyl) pentyl group , 3- (methoxy Rubonyl) pentyl group, 4- (methoxycarbonyl) pentyl group, 5- (methoxycarbonyl) pentyl group, 1- (methoxycarbonyl) hexyl group, 2- (methoxycarbonyl) hexyl group, 3- (methoxycarbonyl) hexyl group, Examples include 4- (methoxycarbonyl) hexyl group, 5- (methoxycarbonyl) hexyl group, 6- (methoxycarbonyl) hexyl group and the like. Preferably, it is “C _2-5 alkoxycarbonyl-C _1-4 alkyl group”. In addition, descriptions such as “C _2-7 ” and “C _2-5 ” in alkoxycarbonyl represent the number of carbon atoms including carbonyl carbon.

  Other groups not defined here follow the usual definitions.

In general formula (1), the “C _1-4 alkyl group” for R ¹ is preferably a methyl group or an ethyl group.

In general formula (1), the “carboxy C _1-4 alkyl group” in R ¹ is preferably a carboxymethyl group.

In the general formula (1), the “C _2-5 alkoxycarbonyl C _1-4 alkyl group” in R ¹ is preferably a methoxycarbonylmethyl group or an ethoxycarbonylmethyl group.

In the general formula (1), the “halogen atom” in R ² and R ³ is preferably a chlorine atom.

In addition, the substitution positions of R ² and R ³ may be any of the 1st to 4th positions, but the 2nd and 4th positions are more preferable.

In general formula (1), the “halogen atom” in R ⁴ is preferably a chlorine atom or a bromine atom.

In general formula (1), the “C _1-4 alkyl group” for R ⁴ is preferably a methyl group.

The substitution position of R ⁴ may be any of the 7th to 10th positions, but the 9th position is more preferred.

  Specific examples of the indolo [2,3-b] quinoxaline compound represented by the general formula (1) of the present invention include the following compounds.

  If the indolo [2,3-b] quinoxaline compound represented by the general formula (1) of the present invention, or a salt thereof, or a solvate thereof is only the indolo [2,3-b] quinoxaline compound of the present invention. And pharmaceutically acceptable salts thereof, various hydrates and solvates thereof, crystal polymorphs thereof, and substances that become prodrugs of these substances.

  As the pharmaceutically acceptable salt of the indolo [2,3-b] quinoxaline compound represented by the general formula (1) of the present invention, specifically, when treating the compound as a basic compound, an inorganic acid ( For example, hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, nitric acid, phosphoric acid, etc.) and organic acids (for example, formic acid, acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, Acid addition salts with lactic acid, malic acid, tartaric acid, citric acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, aspartic acid, glutamic acid, etc.), and when treating a compound as an acidic compound, Inorganic salt (for example, sodium salt, potassium salt, lithium salt, barium salt, calcium salt, magnesium salt) and organic salt (for example, pyridinium salt, picolinium salt, triethyl) Ammonium salt and the like).

  Examples of solvates of the indolo [2,3-b] quinoxaline compound represented by the general formula (1) of the present invention and pharmaceutically acceptable salts thereof include hydrates and various solvates (for example, ethanol). Solvates with alcohols such as

  The indolo [2,3-b] quinoxaline compound represented by the general formula (1) of the present invention can be produced by a known method. As an example of the production method, the method described in WO94 / 24135 is shown below, but is not limited thereto.

[Wherein R ¹ , R ² , R ³ and R ⁴ are the same as those described above, and X represents a leaving group such as a halogen atom]

An indolo [2,3-b] quinoxaline compound (1a) in which R ¹ is a hydrogen atom by heat condensation of 1,2-phenylenediamine compound (I) and isatin compound (II) in an organic acid such as acetic acid. ) Can be manufactured. Compound (III), which is an alkyl halide (methyl iodide, ethyl iodide, etc.) or a halogenoacetic acid derivative (bromoacetic acid, ethyl bromoacetate, etc.), optionally in the presence of sodium hydride, in the presence of compound (1a) Is reacted with an aprotic polar solvent such as dimethyl sulfoxide so that R ¹ is a C _1-6 alkyl group, a carboxy-C _1-6 alkyl group, a C _2-7 alkoxycarbonyl-C _1-6 alkyl group. A certain compound (1b) can be produced. In addition, the compound in which R ¹ is a carboxy-C _1-6 alkyl group is obtained by subjecting the compound (1b) in which R ¹ is a C _2-7 alkoxycarbonyl-C _1-6 alkyl group to a normal hydrolysis reaction. It can also be manufactured.

  Further, for the purpose of avoiding side reactions, the reaction may be carried out by appropriately combining protective deprotection of functional groups. The protection and deprotection conditions can be carried out with reference to commonly used methods (Protective Groups in Organic Synthesis Third Edition, John Wiley & Sons, Inc.).

  Intermediates and target products obtained in the above reactions are necessary for purification methods commonly used in organic synthetic chemistry, such as filtration, extraction, washing, drying, concentration, recrystallization, various chromatography, etc. Can be isolated and purified. In addition, the intermediate can be subjected to the next reaction without any particular purification.

  Furthermore, various isomers can be isolated by a conventional method utilizing the difference in physicochemical properties between isomers. For example, a racemic mixture is converted into a diastereomeric salt with a general optically active acid such as tartaric acid and optically resolved, or by a general racemic resolution method such as a method using optically active column chromatography. Can lead to optically pure isomers. Further, the diastereomeric mixture can be divided by, for example, fractional crystallization or various chromatography. An optically active compound can also be produced by using an appropriate optically active raw material.

  The EPO production promoter or anemia treatment / prevention agent of the present invention contains an indolo [2,3-b] quinoxaline compound represented by the general formula (1), a salt thereof, or a solvate thereof as an active ingredient. And can be used as a pharmaceutical composition. In that case, the compound of the present invention may be used alone, but it is usually used in combination with a pharmaceutically acceptable carrier and / or diluent.

  The administration route is not particularly limited, but can be appropriately selected depending on the purpose of treatment. For example, any of oral preparations, injections, suppositories, inhalants and the like may be used. Pharmaceutical compositions suitable for these dosage forms can be produced by utilizing known preparation methods.

  When preparing an oral solid preparation, the indolo [2,3-b] quinoxaline compound represented by the general formula (1) is a pharmaceutically acceptable excipient, and if necessary, a binder, a disintegrant, After adding a lubricant, a colorant, a flavoring agent, a flavoring agent and the like, tablets, coated tablets, granules, powders, capsules and the like can be produced using conventional methods. Additives may be those commonly used in the art. Examples of excipients include lactose, sucrose, sodium chloride, glucose, starch, calcium carbonate, kaolin, microcrystalline cellulose, silicic acid and the like. Examples of the binder include water, ethanol, propanol, simple syrup, glucose solution, starch solution, gelatin solution, carboxymethylcellulose, hydroxypropylcellulose, hydroxypropyl starch, methylcellulose, ethylcellulose, shellac, calcium phosphate, and polyvinylpyrrolidone. Examples of the disintegrant include dry starch, sodium alginate, agar powder, sodium hydrogen carbonate, calcium carbonate, sodium lauryl sulfate, stearic acid monoglyceride, and lactose. Examples of the lubricant include purified talc, stearate, borax, and polyethylene glycol. Examples of the corrigent include sucrose, orange peel, citric acid, tartaric acid and the like.

  When preparing a liquid preparation for oral use, a conventional method is used by adding a flavoring agent, buffering agent, stabilizer, flavoring agent, etc. to the indolo [2,3-b] quinoxaline compound represented by the general formula (1). Thus, an internal solution, a syrup, an elixir and the like can be produced. As the corrigent, those mentioned above may be used. Examples of the buffer include sodium citrate, and examples of the stabilizer include tragacanth, gum arabic, and gelatin.

  When preparing injections, pH regulators, buffers, stabilizers, tonicity agents, local anesthetics, etc. are added to the indolo [2,3-b] quinoxaline compound represented by the general formula (1) However, subcutaneous, intramuscular and intravenous injections can be produced using conventional methods. Examples of the pH adjusting agent and buffer include sodium citrate, sodium acetate, sodium phosphate and the like. Examples of the stabilizer include sodium pyrosulfite, EDTA, thioglycolic acid, thiolactic acid and the like. Examples of local anesthetics include procaine hydrochloride and lidocaine hydrochloride. Examples of isotonic agents include sodium chloride and glucose.

  When preparing a suppository, a known suppository carrier for the indolo [2,3-b] quinoxaline compound represented by the general formula (1), such as polyethylene glycol, lanolin, cacao butter, fatty acid triglyceride, etc. After adding a surfactant (for example, Tween (registered trademark)) or the like as required, it can be produced using a conventional method.

  In addition to the above, it is possible to appropriately prepare a preferable preparation using a conventional method.

  The dose of the indolo [2,3-b] quinoxaline compound represented by the general formula (1) of the present invention varies depending on age, body weight, symptom, dosage form, number of administrations, etc. As the compound represented by (1), 1 mg to 1000 mg per day is preferably administered orally or parenterally in one or several divided doses.

  EXAMPLES Next, although an Example is given and this invention is further demonstrated, this invention is not limited to these Examples. In addition, the test compounds 1-5 used for the Example used what was obtained from Chembridge, and the test compounds 6-11 used what was obtained from ChemDiv.

Example 1
The EPO production promoting activity by the indolo [2,3-b] quinoxaline compound of the present invention was measured based on the EPO promoter activity.
<Materials and methods>
A vector in which the 5 ′ promoter region and 3 ′ enhancer region of human EPO were linked to the luciferase gene of pGL3 basic (Promega) was introduced into a cell line HepG2 derived from human liver cancer by lipofection. The obtained stable expression strain (HepG2 EPO-luc) was used for the evaluation of the test compound. Next, 5 × 10 ³ cells of HepG2 EPO-luc were seeded in each well of a 96-well plate using a minimum essential medium (MEM) (Sigma) containing 10% fetal bovine serum. Thereafter, the test compound dissolved in DMSO was added to each well to a final concentration of 7.5 μM, and the amount of the medium was 100 μl per well. After incubation for 24 hours in a CO ₂ incubator with an oxygen concentration of 4%, Bright-Glo ™ Luciferase Assay System (Promega) was added at 100 μl / well as EPO promoter activity, and immediately using ARVO (Perkin Elmer) The luciferase activity was measured. The above method was in accordance with the instruction manual attached to the Bright-Glo (trademark) Luciferase Assay System.

  The EPO promoter activity (% of control) induced by each compound was calculated with the EPO promoter activity in an unstimulated state without addition of the compound as 100%. The results are shown in Table 2.

<Result>
EPO production was promoted by adding a test compound at a concentration of 7.5 μM (see Table 2). In particular, compounds 3, 5, and 11 had a strong EPO production promoting action exceeding 1000%. From the above, it has been clarified that these compounds have an EPO production promoting action, and it was found that they are useful as an anemia treatment agent.

  The present invention has found for the first time that the indolo [2,3-b] quinoxaline compound represented by the general formula (1) or a salt thereof, or a solvate thereof has an excellent EPO production promoting action. It is intended to provide an orally administrable low molecular weight anemia preventive and / or therapeutic agent having an excellent EPO production promoting action. The present invention provides a novel low-molecular-weight anemia prevention and / or treatment agent, which is useful in the pharmaceutical industry and has industrial applicability.

Claims (3)

The following general formula (1):

[Where:
R ¹ represents a hydrogen atom, a C _1-6 alkyl group, a carboxy-C _1-6 alkyl group, a C _2-7 alkoxycarbonyl-C _1-6 alkyl group,
R ² and R ³ may be the same or different and each represents a hydrogen atom or a halogen atom;
R ⁴ represents a hydrogen atom, a halogen atom or a nitro group]
The EPO production promoter which uses the indolo [2,3-b] quinoxaline compound represented by these, its salt, or those solvates as an active ingredient. The following compound groups:
9-bromo-6-methyl-6H-indolo [2,3-b] quinoxaline,
6-ethyl-6H-indolo [2,3-b] quinoxaline,
6-methyl-6H-indolo [2,3-b] quinoxaline,
6-methyl-9-nitro-6H-indolo [2,3-b] quinoxaline,
9-bromo-2,4-dichloro-6H-indolo [2,3-b] quinoxaline,
Ethyl 2- (6H-indolo [2,3-b] quinoxalin-6-yl) acetate,
Methyl 2- (6H-indolo [2,3-b] quinoxalin-6-yl) acetate,
Methyl 2- (9-chloro-6H-indolo [2,3-b] quinoxalin-6-yl) acetate,
2- (6H-indolo [2,3-b] quinoxalin-6-yl) acetic acid,
Methyl 2- (9-methyl-6H-indolo [2,3-b] quinoxalin-6-yl) acetate, and 2- (9-methyl-6H-indolo [2,3-b] quinoxalin-6-yl) The EPO production promoter according to claim 1, which is selected from the group consisting of acetic acid.   A prophylactic and / or therapeutic agent for anemia comprising the EPO production promoter according to claim 1 or 2 as an active ingredient.