AZAANTHRACENE COMPOUNDS

Abstract: Azaanthracene compounds of the general formula (wherein one or two of X, Y and Z are nitrogen atoms, the others are CH, R¹ and R² are the same or different and are hydrogen atoms, lower alkyl groups or β-hydroxyethyl groups, and n is 2 or 3) and the acid addition salts thereof have antitumor activity. They can be prepared by reaction of the corresponding 6-ethoxycarbonyl compound with a dialkyl-, or di-­ (hydroxyalkyl)-aminoalkylamine.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to azaanthracene compounds, and more particularly to novel tri- or tetra­ azaanthracene compounds and the salts thereof having antitumor activity. 2. Description of the Prior Art Any tri- or tetraazaanthracene compounds having antitumor activity are not known in the past. Prior art anticancer agents can not be said to be sufficient for their pharmaceutical activity and toxicity. The structures of the anticancer agents used clinically have actively been modified in order to increase antitumor effect and decrease side-effect. But it is desired to find the anticancers having new skeletones for treatment of the cancer which is not recognized to be effective by the prior art drugs and for solving the problem of drug tolerance. SUMMARY OF THE INVENTION As a result of the earnest researches in view of the above circumstances, the inventors have found novel azaanthrancene compounds having high antitumor activity, and the present invention have been completed. The present invention relates to azaanthracene compounds of the formula (I) (wherein one or two of X, Y and Z are nitrogen atoms, the others are CH, R¹ and R² are the same or different and are hydrogen atoms, lower alkyl groups or β-hydroxyethyl groups, and n is 2 or 3) and the salts thereof. The lower alkyl group in the present invention means an alkyl group such as a methyl group, an ethyl group, a propyl group and a butyl group. Preferred compounds of formula (I) are those in which one or two of X, Y and Z are nitrogen atoms, the others are CH, R¹ and R² are both methyl groups, or R¹ is a hydrogen atom and R² is a β-hydroxyethyl group, and n is 2, and the salts thereof. DETAILED DESCRIPTION OF THE INVENTION Azaanthracene compounds of formula (I) are novel and can be prepared from known ethyl 3-hydroxy-­ 1,4-dihydro-1,4-dioxo-2-naphthoate according to the following reaction scheme (wherein X, Y, Z, R¹, R² and n are as defined above). First ethyl 3-hydroxy-1,4-dihydro-1,4-dioxo-2-­ naphthoate is methylated in an alcohol (e.g., ethanol) or diethyl ether with an excess amount of diazomethane in di­ ethyl ether to give ethyl 3-methoxy-1,4-dihydro-1,4-­ dioxo-2-naphthoate, which is then condensed with 1.1 to 1.5 molar equivalents of the compound of formula (III) in an organic solvent at room temperature for 2 to 24 hours to give the compound of formula (II). The methylation is carried out at 0°C to room temperature for 2 to 24 hours. Typical examples of the compound of formula (III) are 3,4-diaminopyridine, 2,3-diaminopyridine, 4,5-diaminopyrimidine and the like. Examples of the organic solvent are methanol, ethanol, dimethyl­ formamide, dimethyl sulfoxide, tetrahydrofuran and the like. Alternatively, ethyl 3-hydroxy-1,4-dihydro-1,4-­ dioxo-2-naphthoate is reacted with N-trimethylsilylimid­ azole (TMS-imidazole) in an organic solvent at O°C to room temperature for 2 to 3 hours, and then the resulting compound is condensed with the compound of formula (III) to give the compound of formula (II). Examples of the organic solvent are dimethylformamide, tetrahydrofuran, dichloromethane, chloroform and the like. The condensation is carried out under the same conditions as those of the above condensation. Next, the compound of formula (II) is reacted with 1.1 to 1.5 molar equivalents of the compound of formula (IV) in an organic solvent at room temperature to 120°C for l to 24 hours to give the compound of formula (I). Typical examples of the compound of formula (IV) are N,N-dimethyl­ ethylenediamine, N,N-dimethyl-1,3-propanediamine, 2-(2-­ aminoethylamino)ethanol and the like. Examples of the organic solvent are benzene, toluene, chloroform, dichloro­ methane, tetrahydrofuran, dimethylformamide, methanol, ethanol and the like. The salts of the compound of formula (I) include salts of inorganic acids such as hydrochloric acid, sulfuric acid and the like, and organic acids such as acetic acid, propionic acid, butyric acid, oxalic acid, malic acid, malonic acid, fumalic acid, benzoic acid, toluic acid and the like which are prepared by treating the compounds of formula (I) with the corresponding acids. The compounds of formula (I) showed antitumor activity on transplanted mouse tumors and are useful for regression or palliation of leukemia in mammals. For the purposes, they may be administered orally, parenterally or locally in conventional dosage forms such as tablets, powders, capsules, solutions, suspensions, emulsions, suppositories and the like, all of which are prepared according to the conventional pharmaceutical practices. The effective dosage of the compounds of formula (I) depends on the age, weight or response of patient. Generally, however, the daily dosage may range from 0.1 to 10 mg/kg. Subsequently, the present invention is illustrated in more detail by examples and a test example. Example 1 (1) Preparation of ethyl 5-hydroxybenzo[f]pyrido­ [3,4-b]quinoxaline-6-carboxylate: In 80 ml of ethanol, were dissolved 1.0 g of 3,4-diaminopyridine and 2.3 g of ethyl 1,4-dihydro-1,4-­ dioxo-3-methoxy-2-naphthoate, and the solution was refluxed for 4 hours. After cooling, the crystals which formed were collected by filtration and recrystal­ lized from ethanol to give the title compound. Yellow needles, m.p. 156-158°C Yield, 1.4 g (2) Preparation of N-β-dimethylaminoethyl 5-hydroxy­ benzo[f]pyrido[3,4-b]quinoxaline-6-carboxamide: In 50 ml of benzene was dissolved 500 mg of ethyl 5-hydroxybenzo[f]pyrido[3,4-b)quinoxaline-6-­ carboxylate obtained by synthesis (l) above. 0.l ml of N,N-dimethylethylenediamine was added, and the mixture was refluxed for 8 hours. After cooling, the crystals which formed were collected by filtration and recrystallized from benzene-petroleum ether to give the title compound. Yellow needles, m.p. 178-182°C Yield, 184 mg Elementary analysis for C₂₀H₁₉N₅O₂ Calcd. (%) C; 66.47, H; 5.30, N; 19.38 Found (%) C; 66.73, H; 5.48, N; 19.37 Example 2 Preparation of N-β-dimethylaminoethyl 5-hydroxybenzo[f]pyrido[3,4-b]quinoxaline-6-carboxamide hydrochloride. In 200 ml of a mixture of dichloromethane and diethyl ether (1:1) was dissolved 2.06 g of N-β-dimethyl­ aminoethyl 5-hydroxybenzo[f]pyrido[3,4-b]quinoxaline-6-­ carboxamide obtained in Example 1(2), dry hydrogen chlo­ ride gas was passed through the solution for 3 to 5 minutes, and then the crystals which formed were collected by filtration to give the title compound. Pale orange needles, m.p. 262-267°C Yield; 2.39 g Elementary Analysis for C₂₀H₁₉N₅O₅·2HCl Calcd. (%) C; 55.17, H; 4.86, N; 16.08 Found (%) C; 55.24, H; 5.00, N; 15.97 Example 3 Preparation of N-2-(2-hydroxyethylamino)ethyl 5-hydroxybenzo[f]pyrido[3,4-b]quinoxaline-6-carboxamide: By the procedure of Example l(2) using 2-(2-aminoethylamino)ethanol in place of N,N-dimethyl­ ethylenediamine, the title compound was obtained. Orange needles, m.p. 167-170°C Yield, 300 mg Elementary Analysis for C₂₀H₁₉N₅O₃ Calcd. (%) C; 63.65, H; 5.07, N; 18.56 Found (%) C; 63.58, H; 5.13, N; 18.54 Example 4 (1) Preparation of ethyl 5-hydroxybenzo[f]pyrido-­ [4,3-b]quinoxaline-6-carboxylate: To 20 ml of dimethylformamide was suspended 2.7 g of ethyl 1,4-dihydro-1,4-dioxo-3-hydroxy-2-naphtho­ ate, 3.23 ml of trimethylsilylimidazole was added, and the mixture was stirred at room temperature for 2 hours. To the mixture was added dropwise under ice-cooling a solution of l.0 g of 3,4-diaminopyridine in 20 ml of dimethylformamide. Successively the mixture was stirred under a nitrogen atmosphere for 30 minutes under ice-cooling and then overnight at room temper­ ature. To the reaction mixture was added water, and the mixture was extracted twice with chloroform. The extract was washed, in turn, with dilute hydrochloric acid, a saturated aqueous sodium bicarbonate solution and an aqueous sodium chloride solution, and dried over sodium sulfate. The solvent was evaporated under reduced pressure, and the resulting residue was purified by silica gel column chromatography (eluent; chloroform : ethanol = 10 : 1) and recrystallized from ethanol to give the title compound. Yellow needles, m.p. 185°C Yield; 1.05 g Elementary Analysis for C₁₈H₁₃N₃O₃ Calcd. (%) C; 67.70, H; 4.11, N; 13.16 Found (%) C; 67.75, H; 4,44, N; 13.28 (2) Preparation of N-β-dimethylaminoethyl 5-hydroxy­ benzo[f]pyrido[4,3-b]quinoxaline-6-carboxamide: In 40 ml of benzene was dissolved 700 mg of ethyl 5-hydroxybenzo[f]pyrido[4,3-b]quinoxaline-6-­ carboxylate obtained by synthesis (1) above, 386 mg of N,N-dimethylethylenediamine was added, and the mixture was refluxed for 30 minutes. After cooling, the crystals which formed were collected by filtration and recrystallized from ethanol to give the title compound. Yellow needles, m.p. 190-191°C Yield; 561 mg Elementary Analysis for C₂₀H₁₉N₅O₂ Calcd. (%) C; 66.47, H; 5.30, N; 19.38 Found (%) C; 66.62, H; 5.45, N; 19.49 Example 5 (1) Preparation of ethyl 5-hydroxybenzo[f]pyrido­ [3,2-b]quinoxaline-6-carboxylate: By the procedure of Example l(l) using 2,3-diaminopyridine in place of 3,4-diaminopyridine, the title compound was obtained. Yellow powder, m.p. 188-190°C Yield, 4.4 g (2) Preparation of N-β-dimethylaminoethyl 5-hydroxy­ benzo[f]pyrido[3,2-b]quinoxaline-6-carboxamide: To 100 ml of benzene were added consecutively 600 mg of ethyl 5-hydroxybenzo[f]pyrido[3,2-b]­ quinoxaline-6-carboxylate, 0.2 ml of N,N-dimethyl­ ethylenediamine and 10 mg of sodium ethylate, and then the mixture was refluxed for 9 hours. After completion of the reaction, the mixture was evaporated to dryness under reduced pressure, and the residue was recrystallized from ethanol to give the title compound. Orange powder, m.p. 208-211°C (decomposition) Yield; 650 mg Elementary Analysis for C₂₀H₁₉N₅O₂ Calcd. (%) C; 66.47, H; 5.30, N; 19.38 Found (%) C; 66.21, H; 5.29, N; 19.43 Example 6 Preparation of N-γ-dimethylaminopropyl 5-hydroxy­ benzo[f]pyrido[3,2-b]quinoxaline-6-carboxamide: By the procedure of Example 1(2) using ethyl 5-hydroxybenzo[f]pyrido[3,2-b]quinoxaline-­ 6-carboxylate and N,N-dimethyl-1,3-propanediamine, the title compound was obtained. Orange powder, m.p. 175-178°C (decomposition) Yield, 100 mg Elementary Analysis for C₂₁H₂₁N₅O₂ Calcd. (%) C; 67.18, H; 5.64, N; 18.66 Found (%) C; 67.20, H; 5.76, N; 18.72 Example 7 Preparation of N-2-(2-hydroxyethylamino)ethyl 5-hydroxybenzo[f]pyrido[3,2-b]quinoxaline-6-carboxamide: By the procedure of Example 1(2) using ethyl 5-hydroxybenzo[f]pyrido[3,2-b]quinoxaline-6-­ carboxylate and 2-(2-aminoethylamino)ethanol, the title compound was obtained. Orange powder, m.p. 183-190°C Yield, 700 mg Elementary Analysis for C₂₀H₁₉N₅O₃ Calcd. (%) C; 63.65, H; 5.07, N; 18.56 Found (%) C; 63.62, H; 5.00, N; 18.44 Example 8 (1) Preparation of ethyl 5-hydroxynaphtho[2,1-g]­ pteridine-6-carboxylate: By the procedure of Example l(l) using 4,5-diaminopyridine in place of 3,4-diaminopyridine, the title compound was obtained. Orange needles, m.p. 132-133°C Yield, 1.2 g (2) Preparation of N-β-dimethylaminoethyl 5-hydroxy­ naphtho[2,1-g]pteridine-6-carboxamide: By the procedure of Example l(2) using ethyl 5-hydroxynaphtho[2,1-g]pteridine-6-carboxylate and N,N-­ dimethylethylenediamine, the title compound was obtained. Orange needles, m.p. 181-182°C Yield, 550 mg Elementary Analysis for C₁₉H₁₈N₆O₂ Calcd. (%) C; 62.97, H; 5.01, N; 23.19 Found (%) C; 63.01, H; 5.00, N; 23.20 Example 9 Preparation of N-γ-dimethylaminopropyl 5-hydroxy­ naphtho[2,1-g]pteridine-6-carboxamide: By the procedure of Example 8(2) using N,N-­ dimethyl-l,3-propanediamine in place of N,N-dimethyl­ ethylenediamine, the title compound was obtained. Orange fine needles, m.p. 105-108°C Yield, 200 mg Elementary Analysis for C₁₀H₂₀N₆O₂ Calcd. (%) C; 63.82, H; 5.36, N; 22.33 Found (%) C; 63.80, H; 5.34, N; 22.42 Test example P388 Lymphocytic Leukemia Test (1) Test animal Female, CDF₁ mice (5-6 weeks old, weighing 17-20 g) were intraperitoneally transplanted with 1 × 10⁶ cells of p388 lymphocytic leukemia passaged on female, DBA/2 mice on day 0. (2) Administration route A suspension of the compound of formula (I) in 0.5% of gum arabic saline solution was adminis­ tered intraperitoneally once a day, 5 times in all, from day l to day 5, or 2 times in all, day l and day 5. A solution of 5-fluorouracil in saline served as a reference drug, and was administered similarly. Control group were similarly administered with only 0.5% gum arabic saline solution. Eight animals were used for the treated group with the compound of formula (I) and the reference drug, respectively, and 16 animals for control group. (3) Evaluation method The antitumor effect was evaluated according to the criterion of the National Cancer Institute of the United States (NCI). The survivors of each group were recorded for 30 days, and the value of T/C × 100 (%) was calculated from the median survival times for the treated animals (T) and the control animals (C). When the value is 125 or more, the drug is judged to be effective. (4) Results of test The results of the test are shown in Table 1. The compounds of formula (I) of the present invention indicated significant value of T/C × 100.

Claims: 1. An azaanthracene compound of the general formula (wherein one or two of X, Y and Z is (are each) a nitrogen atom, and the or each other is CH, R¹ and R² are the same as or different from one another and are each a hydrogen atom, lower alkyl group or β-­ hydroxyethyl group, and n is 2 or 3) or a salt thereof. 2. An azaanthracene compound according to Claim l, wherein one or two of X, Y and Z is (are each) a nitrogen atom, the or each other is CH, R¹ and R² are both methyl groups, and n is 2. 3. An azaanthracene compound according to Claim l, wherein one or two of X, Y and Z is (are each) a nitrogen atom, the or each other is CH, R¹ is a hydrogen atom, R² is a β-hydroxyethyl group, and n is 2. 4. N-β-dimethylaminoethyl 5-hydroxybenzo[f]pyrido­ [3,4-b]quinoxaline-6-carboxamide. 5. N-β-dimethylaminoethyl 5-hydroxybenzo[f]pyrido­ [3,4-b]quinoxaline-6-carboxamide hydrochloride. 6. N-2-(2-hydroxyethylamino)ethyl 5-hydroxybenzo­ [f]pyrido[3,4-b]quinoxaline-6-carboxamide. 7. N-β-dimethylaminoethyl 5-hydroxybenzo[f]pyrido­ [4,3-b]quinoxaline-6-carboxamide. 8. N-β-dimethylaminoethyl 5-hydroxybenzo[f]pyrido­ [3,2-b]quinoxaline-6-carboxamide. 9. N-2-(2-hydroxyethylamino)ethyl 5-hydroxybenzo­ [f]pyrido[3,2-b]quinoxaline-6-carboxamide. l0. N-β-dimethylaminoethyl 5-hydroxynaphtho[2,1-g]­ pteridine-6-carboxamide. 11. A method for preparing a compound of the general formula (I), given and defined in Claim l, or salt thereof, which method comprises condensing a compound of the general formula (II) (wherein X, Y and Z are as defined in Claim l with an alkyl­ amine of the general formula (IV) (wherein R¹, R² and n are defined in Claim l). 12. A method according to Claim ll, wherein the condensation is carried out in an organic solvent at a temperature of from room temperature to 120°C inclusive for a period of from l to 24 hours inclusive. Claims for the following Contracting States: AT, ES, GR: 1. A method for preparing a compound of the general formula (I) (wherein one or two of X, Y and Z is (are each) a nitrogen atom, and the or each other is CH, R¹ and R² are the same as or different from one another and are each a hydrogen atom, lower alkyl group or β-hydroxyethyl group, and n is 2 or 3) or a salt thereof, which method comprises condensing a compound of the general formula (II) (wherein X, Y and Z are as defined above with an alkyl­ amine of the general formula (IV) (wherein R¹, R² and n are defined above). 2. A method according to Claim l, wherein the condensation is carried out in an organic solvent at a temperature of from room temperature to l20°C inclusive for a period of from l to 24 hours inclusive. 3. A method according to Claim l or Claim 2, wherein, in the compound of the formula (I), one or two of X, Y and Z is (are each) a nitrogen atom, the or each other is CH, R¹ and R² are both methyl groups, and n is 2. 4. A method according to Claim l or Claim 2, wherein, in the compound of the formula (I), one or two of X, Y and Z is (are each) a nitrogen atom, the or each other is CH, R¹ is a hydrogen atom, R² is a β-hydroxyethyl group, and n is 2. 5. A method according to Claim 3, wherein the compound of the formula (I) is N-β- dimethylaminoethyl 5-hydroxybenzo [f]pyrido[3,4-b]quinoxaline-6-carboxamide. 6. A method according to Claim 3, wherein the compound of the formula (I) is N-β-dimethylaminoethyl 5-hydroxybenzo[f]pyrido[3,4-b]quinoxaline-6-carboxamide hydrochloride. 7. A method according to Claim 4, wherein the compound of the formula (I) is N-2- (2-hydroxyethylamino)ethyl 5-hydroxybenzo[f]pyrido[3,4-b]quinoxaline-6-carboxamide. 8. A method according to Claim 3, wherein the compound of the formula (I) is N-β-dimethylaminoethyl 5-hydroxybenzo[f]pyrido[4,3-b]quinoxaline-6-carboxamide. 9. A method according to Claim 3, wherein the compound of the formula (I) is N-β-dimethylaminoethyl 5-hydroxybenzo[f]pyrido[3,2-b]quinoxaline-6-­ carboxamide. 10. A method according to Claim 4, wherein the compound of the formula (I) is N-2-(2-hydroxyethylamino) ethyl 5-hydroxybenzo[f]pyrido[3,2-b]quinoxaline-6-­ carboxamide. 11. A method according to Claim 3, wherein the compound of the formula (I) is N-β-dimethylaminoethyl 5-hydroxynaphtho[2,1-g]-pteridine-6-carboxamide. 12. A method for preparing an azaanthracene compound, wherein the said compound has the general formula (I) (wherein one or two of X, Y and Z is (are each) a nitrogen atom, the or each other is CH, R¹ and R² are the same as or different from one another and are each a hydrogen atom, lower alkyl group or β-hydroxyethyl group, and n is 2 or 3) or a salt thereof.

Inventors: AMANO, TAKEHIRO, EGUCHI, TADASHI, NAKAGAMI, JOZI, SAKAKIBARA, JINSAKU, SOTA, KAORU
Applicants: TAISHO PHARMACEUTICAL CO. LTD
Application year: 1987
Main classification: C07D471
IPC codes: C07D471, C07D475, A61P35, A61K31