MXPA96003994A - An improved method of synthesis for 6,9-bis [(2-aminoethyl) amino] benzo [g] -isoquinolin-5, 10-diona and its dimale salt - Google Patents

Abstract

The present invention relates: In the invention of novel heteroanalogs of anthracendiones, the dimaleate salt of 6,9-bis [(2-aminoethyl) aminobenzo [g] isoquinoline-5,10-dione (BBR 2778), was selected as the most promising compound. The novel methods of synthesis produce a compound with a purity greater than 9

Description

AN IMPROVED METHOD OF SYNTHESIS FOR IA 6,9-BIS [(2-AMINOETIDAMINO] BENZO [g] SOQUINOLIN-5, 10-DIONA AND ITS SALT FROM DIM? LEATO FIELD OF THE INVENTION Mitoxantrone (Mitox), a 1/4-bis (aminoalkylamino) anthracen-9-10-dione antitumor, is currently gaining an important place in the clinical management of leukemias and lymphomas as well as in the combined therapy of breast and ovary. Although Mitox is endowed with an improved tolerability profile compared to doxorubicin (DX) and other anthracyclines, this drug does not avoid significant toxic side effects, especially those associated with myelosuppression and cardiotoxicity. In particular, congestive heart failure is a serious clinical concern in patients previously treated with anthracyclines (for a recent review of the therapeutic and toxicological profile of mitoxantrone see: Faulds, D .; Balfour, JA; Chrisp, P .; Langtry, HD "Mitoxantrone, a Review of its Pharmacodynamic and Pharmacokinetic Properties, and Potential REF: 22751 Therapeutic in Cancer Chemotherapy", Drugs 1991, 41, 400-449). The mechanisms of Mitox cell destruction are probably multimodal in nature: many studies suggest intercalation in DNA as a major cellular event. The compaction of the nucleic acid and the interference with DNA-Topoise erasa II activity, which result in breaks in the DNA strand associated with the protein have also been proposed as critical events that lead to cell death induced by Mitox. Cellular destruction by antitumor-9, 10-diones antitumor, including Mitox, has also been attributed to oxidative metabolism, which results in the formation of free radicals capable of alkylating DNA and / or breaking DNA, resulting in breakage in the strand of DNA not associated with the protein. However, it is generally believed that the redox cyclization of the quinone portion is probably more related to the cardiotidal side effects of Mitox than to the mechanism of its antitumor activity. The cardiotoxicity of Mitox and DX has also been associated with the ability to chelate metals from the adjacent hydroxyl and quinone groups. The formation of pharmaco-metal complexes could increase the oxidation-reduction cyclization by a reaction of the type catalyzed by a metal (Shipp, NG, Dorr, RT, Alberts, D.S., Dawson, BV, Hendrix, M. "Experimental characterization of the cardiotoxicity of mitoxantrone and its partial inhibition by ICRF-187 in cultured neonatal rat heart cells ", Canner Res. 1993, 53, 550-556). The significant clinical activity of Mitox ^ "/ * _ Makes the development of the second generation of congeners of the anthracite an attractive area of investigation. To date, much research has been devoted to the exploration of the variations in the nature of the side chains and the relocation of hydroxy substituents and / or chains. laterals. The introduction of heteroatoms in the anthraquinone chromophore is a relatively unexplored method, but such a change could significantly affect the interaction of the molecules with targets or biological targets. In particular, the heterocyclic analogues of the anthraquinones a) could basically retain the same spatial and planar characteristics as the original drugs for molecular recognition of the host such as the DNA intercalation, and b) can introduce additional hydrogen bonds or base sites, any of which could increase the drug's affinity for DNA and / or affect the interaction with Topoisomerase II.

In addition, hetero-analogs could be endowed with altered redox properties. Various aza analogues have been prepared and selected (Krapcho, AP, "6, 9-bis (substituted amino) benzo [g] isoquinolin-5,10-diones." PCT International Application WO 92/15300, Sept. 17, 1992 0 ( incorporated herein by reference) / AP Krapcho et al .: "6, 9-bis [(2-aminoalkyl) aminobenzo [g] isoquinolin-5,10-diones." A novel class of anthracene-9, 10-diones antitumor modified with chromophore: synthesis and antitumor evaluation; J. Med. Chem (1994), in press 5 (incorporated herein by reference). Among those compounds the dimaleate salt of 6,9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5,10-dione emerged as the most active and experimental antitumor models. 0 The dimaleate salt of 6,9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5,10-dione also avoids any significant toxic effect on cardiac tissue, after both simple and multiple treatment, respectively in rats and mice. After a simple treatment in rats with doses approximately equal to DL and LD50, the dimaleate salt compound of 6,9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5,10-dione induced less erythropenia and thrombocytopenia than Mitox. This favorable profile was confirmed in mice after repeated treatments compared to mitoxantrone at equitable doses in murine leukemia models. Unfortunately the chemical development of the compound faced unexpected problems due to the low level of purity of the compound (purity as low as 96%). The analytical development of the compound also revealed the presence of unknown impurities that are formed during the last step of the preparation process and that could not be removed from the compound with any purification method currently available. Since unknown impurities constitute more than 2%, and one of those unknown impurities alone constitutes 1.3%, the development of the compound is seriously endangered since the regulatory authorities require extensive investigations of unknown impurities in case these are presented later in significant quantities.

BRIEF DESCRIPTION OF THE INVENTION Applicants have discovered new improved synthesis methods for 6,9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5,10-dione and its simaleate salt. By the new improved synthesis methods of the invention, this compound can be obtained with a purity greater than 99%.

B-REVE DESCRIPTION OF THE DRAWINGS Figure 1: analysis by CLAP that reports a mixture of the compound of the invention, peak 6, and the impurities identified. Figure 2: CLAP analysis of a real sample of the compound of the invention made by the prior art J. Med. Chem. Or WO 92/15300 for the bis-maleate. The peaks in the extended retention times, peaks 7, 8 and 9, are the unknown impurities. Figure 3: CLAP analysis of the compound of the invention prepared according to process A of the invention.

Figure 4: CLAP analysis of the compound of the invention prepared according to process B of the invention.

DETAILED DESCRIPTION OF THE INVENTION The compound of the invention, 6, 9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5, 10-dione or its dimaleate salt, was made by two improved methods which resulted in the production of the composed with a very high purity. 6, 9-bis [(2-aminoethyl) amino] benzo [g] isoquinolin-5,10-dione as the free base is not stable because it rapidly cycles in solution leading to compounds la and lb which in CLAP they form two different peaks due to any compound (see Figure 1) .

In addition, the free base is very soluble in water; therefore, it can be extracted with difficulty with organic solvents and is very difficult to handle and purify. In addition, other salts of 6, -bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5,10-dione, such as the hydrochloride salt, decompose during rest because they are intrinsically very acidic. In effect, the compound 6, 9-bis [(2-aminoethyl) amino] benzo [g] isoquinolin-5, 10-dione acid pH (less than 2.5) decomposes forming the compounds 2a and 2b in which lose a side chain. Compounds 2a and 2b are indistinguishable in CLAP and form a single peak (see Figure 1). All the decomposition products reported above are present as impurities in 6,9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5,10-dione (see Figure 2, peaks 3, 4 and 5) . The dimaleate salt on the contrary is endowed with an excellent intrinsic stability. The prior art methods that report the synthesis of 6,9-bis [(2-aminoethyl) amino] benzo [g] iso-quinolin-5,10-dione and its dimaleate salt are reported in: 1) WO 92/15300 and 2) AP Krapcho et al. "6,9-bis [(2-aminoalkyl) amino] benzo [g] isoquinolin-5,10-diones.

A novel class of anthracen-9, antitumor 10-diones modified with chromophore: synthesis and antitumor evaluations ", J. Med. Chem. (1994), in press The synthetic processes reported use, as a key intermediate, 6, 9-difluorobenzo [g] isoquinolin-5,10-dione This compound is reacted with ethylenediamine which produces 6,9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5,10-dione. method involving the reaction of 6,9-difluorobenzo [g] isoquinolin-5, 10-dione with mono-t-butoxycarbonyl-ethylene-diamine (BOC-ethylene diamine) and the subsequent removal of the protective BOC group with dry HCl which leads to the 6,9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5,10-dione hydrochloride salt The conversion of the HCl salt to the stable dimaleate salt is not feasible Because HCl is not exchanged with the less acid maleic acid, in addition, the HCl salt, once dissolved in water, decomposes. Prior art 1) does not lead to the preparation of 6,9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5,10-dione or its dimaleate salt with a purity higher than 96.1%, and ) does not avoid the presence of unidentified impurities that are formed during the last step of the process. Figure 2 reports the analysis by CLAP of a typical dimaleate salt batch of 6, 9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5,10-dione prepared according to the prior art method: three unknown impurities are present (see peaks 7, 8 and 9) which constitute more than 2% among which one of them (ie peak 8) is approximately 1.3%. The purity of the compound could not be increased and the presence of unknown impurities could not be avoided: by the suspension or repeated crystallization in different solvents or solvent mixtures since the amount of unknown impurities remains constant, by column chromatography or by carrying out the last step of the synthetic process in different solvents and at different temperatures.

Furthermore, according to the methods of the prior art, during the work of the last step the precipitation of the compound as a dimaleate salt is obtained in the presence of a crude dorohydrate suspension.A complete solution is never achieved. In the escalation of the process, this suspension can lead to an inhomogeneous product which could trap other salts and / or contain undesirable materials (ie, insoluble materials, impurities). Complete dilution of the final product, at least once during the final process, is an important prerequisite for obtaining a chemical compound that is intended for use in mammalian therapy. Those typical disadvantages of the synthetic processes of the prior art constitute a serious obstacle to the production and development of the compound of the invention. Regulatory authorities usually do not allow the introduction to human treatments of 5 drugs with the active ingredient ingredient with a purity lower than 96%, particularly if the unknown impurities that are present contribute more than 2%. It is highly preferable to avoid the presence of any impurities present in amounts greater than 0.5%. We now surprisingly provide novel processes that make it possible to obtain 6,9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5,10-dione and its dimaleate salt with a purity greater than 97%, and 5 preferably greater than 99%, with each of the "*" contained impurities present in amounts less than 0.5%, and with each of the unknown impurities less than 0.2%, that is, at the limit of detection of the analytical method. The formation of 6,9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5,10-dione and its dimaleate salt can be carried out using any of the following processes: Process A: Including the following novel characteristics: the reaction of 6,9-bis [(2-aminoethyl) aminojbenzo [g] isoquinoline-5,10-dione with ethylene diamine is carried out by inverse addition, that is, slowly adding 6,9-dorobenzo [g] isoquinoline -5, 10-dione solid to a solution of a large excess of diamine in THF. the 6,9-bis [(2-aminoethyl) aminoj-benzo [g] isoquinoline-5,10-dione dorohydrate obtained from the reaction mixture is completely dissolved in water and acetic acid at pH = 5; the solution is then filtered and from the above solution the dimaleate salt is crystallized by the addition of a solution of maleic acid in water.

The inverse addition and the speed of addition by itself are critical for the high purity of the product and allow to obtain very high yields (92%). The selection of the solvent is also very important: the use of THF instead of pyridine improves the yield. The dissolution of the crude dorohydrate is important for the high purity and homogeneity of the final product. In addition, the pH at which the solution is made is critical to avoid the formation of other undesirable impurities. The complete procedure is described in Example 1, below.

Process B: Including the following novel characteristics: Intermediate 6,9-dorobenzo [g] isoquinoline-5,10-dione is reacted with mono-BOC-ethylenediamine and 6,9-bis [2 [N (t-butoxycarbonyl) amino] ethyl] amino] benzo [ g] intermediate isoquinoline-5,10-dione is treated with troroacetic acid leading to the troroacetate salt of 6,9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5,10-dione crude which is then completely dissolved in water, the pH is adjusted to 4.2 with NaOH, and filtered; The above solution of the crude troroacetate salt is treated with an aqueous solution of maleic acid leading to the crystallization of the dimaleate salt of 6,9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5,10. -Diona pure. The complete procedure is described in Example 4, below.

We have surprisingly discovered that the desired 6,9-bis [(2-aminoethyl) amino] ben-zo [g] isoquinoline-5,10-dione dimaleate can be obtained by the displacement of corresponding crude trifluoroacetate which can be obtained by the removal of the BOC protecting groups with trifluoroacetic acid. The preparation of key intermediate 6, 9-difluorobenzo [g] iso-quinolin-5, 10-dione can be achieved by an improved multi-step process. The improvements have been introduced to increase the yields and to allow the scaling of the process, which is essentially for the pharmaceutical development of 6,9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5, 10- diona The reaction of 1,4-difluorobenzene with pyridine-3,4-dicarboxylic anhydride in the presence of aluminum chloride leads to a mixture of 4- (2 and 5 '-difluorobenzoyl) nicotinic acid and 3- (2', 5) acid. '-difluorobenzoyl) isonicotinic was conducted as described with the modification that the reaction mixture is diluted with nitrobenzene after recovering the excess 1,4-difluorobenzene and then slowly pouring the water. The prior art process required the addition of water to the complete semisolid reaction mixture, after recovering the excess 1,4-difluorobenzene: this procedure is extremely risky and is not suitable to be reproduced on a large scale due to the reaction Highly exothermic aluminum chloride with water. The new work allows to slowly add a solution of the remaining aluminum complexes and excess chloride to a large excess of water.

The resulting mixture of 4- (2 ', 5'-difluorobenzoyl) nicotinic acid and 3- (2', 5'- (difluorobenzoyl) isonicotinic acid is then subjected to a cyclization reaction in 20% fuming sulfuric acid with the improvement that the additional portion addition of 20% smoky sulfuric acid increases yields up to 81%.

Preparatory Example 1: Preparation of 3-pyridine dicarboxylic acid anhydride Under a nitrogen atmosphere a suspension of 97% pure 3,4-pyridine dicarboxylic acid (152 g, 0.88 mol) in acetic anhydride (450 mL) was heated to reflux and a complete solution was obtained. Once the reflux temperature was reached, the solvent was removed by distillation at atmospheric pressure (approximately 400 mL was collected) for a period of about 1 hour. It was observed that the temperature of the vapors increased from approximately 132 ° C to 140 ° C and the distillation stopped when the internal temperature reached 150-155 ° C. The reaction mixture was cooled to 70 ° C and ter-BuOMe (450 mL) was added dropwise under stirring.A dark gray solid precipitated at about 40 ° C while the temperature was spontaneously reached at 20-25 ° C. C. The suspension was further cooled to 0-5 ° C and stirred for two hours Under the nitrogen stream the gray precipitate was collected by filtration, washed with ter-BuOMe (100 mL) and dried under vacuum (20 torr; 30 ° C; 2 h) to give the 3,4-pyridine dicarboxylic acid anhydride (100 g, 76% yield) which was directly used in the next step.The 3,4-pyridine dicarboxylic acid anhydride is highly sensitive to atmospheric humidity so that it must be handled under nitrogen and stored on P205, mp 72-74 ° C.

Preparatory Example 2: 4- (2 ', 5' -difluorobenzoyl) nicotinic acid acid 3- (2 ', 5' - (difluorobenzoyl) isonicotinic The anhydride of 3,4-pyridine dicarboxylic acid (95.7 g, 0.67 mol) and A1C13 (367.3 g, 2.67 mol) were added simultaneously, but separated into five portions (one each 15 ') to the boiling 1,4-difluorobenzene. (650 mL, 90 ° C). Approximately 1 hour after the last addition, most of the 1,4-difluorobenzene was removed by distillation at normal pressure until a thick mass was obtained. The temperature was lowered to 80 ° C and nitrobenzene (150 mL) was added to dissolve the residual mass. While heating continued, the resulting solution was carefully cooled in stirred water and cooled with ice (100 g of ice and 530 g of demineralized water).(ie, slowly dripping the solution into the ice water). Then concentrated HCl (37%, 160 mL) was added to the mixture poured at 0-5 ° C and stirring was continued for about 3 hours. A "fatty beige" precipitate was collected by filtration (approximately 150 g of wet mass) while the aqueous layer was separated from the nitrobenzene and extracted with AcOEt (6 x 500 mL). The nitrobenzene layer was diluted with petroleum ether (400 mL) and the resulting small amount of precipitate was collected by filtration (approximately 2 g). The combined extracts were concentrated under vacuum, and the residual crude solid (approximately 45 g), together with the previously collected precipitates, was suspended in a mixture of AcOEt / petroleum ether (1/1) (600 mL). After about 2 hours at room temperature the suspension was filtered and dried under vacuum to give the mixture of 4- (2 ', 5'-difluorobenzoyl) nicotinic acid and 3- (2', 5 '- (difluorobenzoyl) isonicotinic acid ( 147.3 g, 84% yield) as a pale beige solid, mp 214-216 ° C Preparatory Example 3: 6, 9-difluorobenzo [g] iso < quinolin-5, 10-dione A solution of the mixture of 4- (2 ', 5'-difluorobenzoyl) nicotinic acid and 3- (2', 5 '- (difluorobenzoyl) isonicotinic acid (120 g, 0.456 mol) in the 20% fuming H2SO4 (180 mL) was heated to 140 ° C. After approximately 30 minutes, more 20% fuming sulfuric acid (120 mL) was added to the hot reaction mixture in four 30 mL portions each, every 20 minutes. from the last addition the reaction mixture was cooled to about 80 ° C and then poured into demineralized water with ice (3000 g of ice and 3000 mL of water) The pH of the cold reaction mixture was adjusted to 1 with NaOH at 40% (850 L) and the formation of a brown yellow precipitate was observed. After about 1 hour at 0-5 ° C the crude precipitate was filtered and dried under vacuum to give crude 6,9-difluorobenzo [g] isoquinoline-5,10-dione (98.5 g). The crude reaction was dissolved in boiling THF (1000 mL) and the hot solution was decolorized with activated carbon (9 g), filtered and concentrated to a volume of approximately 300 mL. After cooling to 0-5 ° C for about 2 hours a yellow solid was collected by filtration to obtain analytically pure 6,9-difluorobenzo [g] isoquinoline-5,10-dione (90.6 g, 81% yield). ). p.f. 197-199 ° C Example 1; 6,9-bis [(2-aminoethyl) amino] benzo [g] iso ui-nolin-5,10-dione dimaleate To a warm solution (55 ° C) of ethylene diamine (154.4 mL, 2.29 mol) in THF (1400 mL), 6,9-difluorobenzo [g] isoquinoline-5,10-dione (70.1 g) was added portionwise. , 0.29 mol) over a period of 2.5 hours (approximately 4.6 g / 10 'each portion). The mixture was stirred for three hours at the same temperature and a blue precipitate formed gradually. After one night of stirring at 25 ° C, the suspension was filtered under a stream of nitrogen, washed with THF (200 mL) and dried under vacuum (15 torr, 60 ° C, 3 h) to give the difluorohydrate salt of 6,9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5,10-dione (117 g). The crude product was dissolved directly in a mixture of water (2340 mL) and AcOH (40 mL) to obtain a dark blue solution, whose pH was about 5, which was filtered on a glass fiber filter. This pH value is very important to avoid any degradation of the reaction product. The filtered solution was gradually treated at room temperature with a filtered aqueous solution of 3M maleic acid (585 L) to reach the pH of 3.5. After about 30 'at 40 ° C, the suspension was stirred overnight at room temperature. The blue precipitate was filtered and washed with additional water (3 x 80 mL) and EtOH (3 x 100 mL) and then dried under vacuum (15 torr, 60 ° C, 4 h) to give the dimaleate of 6, 9-bis. [(2-aminoethyl) amino] benzo [g] isoquinoline-5, 10-dione (168 g). The crude dimaleate salt was suspended in water (3180 mL) and heated at 50 ° C for 30 '. After one night of stirring at 25 ° C, the suspension was filtered again, the blue precipitate was washed with additional water (3 x 100 mL) and this wet material was resuspended in water (2400 mL) and stored with stirring at room temperature for approximately 40 h. The dimaleate salt was filtered, washed with additional water (3 x 100 mL) and EtOH (3 x 100 mL) and then dried under vacuum (15 torr, 60 ° C, 4 h, then 40 ° C, overnight) to produce the dimaleate of 6,9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5,10-dione (146.7 g, 92% yield).

Analysis by CLAP (Waters, UV detector / Vis 486, Pump 510): Column: Lichrospher C18 (5 μm) t.a. eluent: H20 / CH3CH / dioxane 75/20/5 Heptan sodium sulfonate (20 mMol) pH 3.0 with H3P04 flow rate: 1 mL / min detector: UV (245 nm) t.r. : 12 min purity by CLAP (area%) = 99.586%; see the Figure 3, peak # 4 Analysis of ^ -RMN (Brucker spectrometer of 200 MHz, chemical shifts (d) are reported in parts per million downstream of the internal Me4Si standard). (6; D20): 3.30 (m, 4H); 3.70 (, 4H); 6.05 (s, 4H); 7.05 (s, 2H); 7.70 (d, 1H); 8.70 (d, 1H); 8.95 (s, 1H).

Example 2 Under a nitrogen atmosphere a solution of di-t-butyl dicarbonate (290.8 g, 1.32 mol) in dry THF (1200 mL) was slowly added over a period of about 3 h to a cold (0 ° C) solution with stirring of 1,2-ethylene diamine (268 mL, 4 mol) in THF (3600 mL). After 3 hours at 10 ° C and about 16 hours at room temperature, the solvent was removed under vacuum. The residual yellow oil (approximately 230 g) was dissolved in isopropyl ether (460 mL) and washed with brine (50 mL). After drying over sodium sulfate (50 L) the organic solution was concentrated to a small volume and distilled under reduced pressure (8 torr, 119-121 ° C) to give the Nt-butoxycarbonyl-1,2-ethylene diamine ( 161 g, yield 76% with respect to di-t-butyldicarbonate). 1.3 (s, 2H) is exchanged with D20), 1.4 (s, 9H), 2.7 (broad t, 2H), 3.1 (dd, 2H), 5.4 (broad s, 1H) Example 3 Under nitrogen a solution of 6,9-difluorobenzo [g] isoquinolin-5,10-dione (15 g, 0.61 mol) and Nt-butoxycarbonyl-1,2-ethylenedimine (49 g, 0.305 mol) in anhydrous N-methylpyrrolidone ( 300 mL) was heated to 60 ° C. After about 4.5 hours, the reaction mixture was slightly cooled (50 ° C) and poured into demineralised water with stirring (1500 mL). Stirring was continued for 2 hours at room temperature and the dark blue precipitated solid was collected by filtration and washed with water. The crude filtered precipitate was resuspended in water (1500 mL), filtered and dried under vacuum. The crude reaction was dissolved in a hot mixture of methylene chloride and methanol (1/1, 1500 L), the hot solution was filtered on a glass fiber filter and cooled at 10-15 ° C for two hours. After an additional 16 hours at room temperature the dark blue crystallized product was collected by filtration and dried to give 27 g of 6,9-bis [(2-Nt-butoxycarbonylaminoethyl) amino] benzo [g] isochiolin-5, 10. -diona (84% yield).

NMR (CDC13, d): 1.4 (s, 18H), 3.4-3.7 (m, 8H), 5.4 (m, 2H), 7.3 (s, 2H), 8 (d, J = 6 Hz, 1H), 8.85 (d, J = 6 Hz, 1H), 9.5 (s, 1H), 11 (m, 2H) Example 4 Trifluoroacetic acid (32 mL, 0.42 mol) was added to a suspension of 6,9-bis [(2-N-tert-butoxycarbonyl-aminoethyl) amino] benzo [g] isoquinoline-5,10-dione (22 g, 0.042). mol) in methylene chloride (330 mL). After stirring for about 16 hours at room temperature, the reaction mixture was diluted with EtOH (100 L) and concentrated under vacuum. The residual oil was again diluted with ethanol (300 mL) and concentrated again to a small volume. Demineralized water (220 mL) was added to the oily residue and the pH was adjusted to 4.2 units with 20% aqueous KOH (45 mL). The dark blue solution obtained was filtered on a glass fiber filter and mixed with an aqueous solution of 3M maleic acid (45 mL, 0.135 mol). The pH of the solution was readjusted to 3.4 units with 20% KOH (24 mL) and the mixture was stirred at room temperature for approximately 40 hours. The crude maleate was collected by filtration and resuspended in demineralized water (200 mL), heated at 50 ° C for 1 hour and stored with agitation for an additional 16 hours at room temperature. A dark blue solid was filtered, washed with water (2 x 50 mL) and ethanol (2 x 50 mL) and dried under vacuum to yield 18.6 g of 6,9-bis [(2-aminoethyl) amino] dimaleate salt] benzo [g] isoquinolin-5,10-dione (80% yield).

Analysis by CLAP (Waters, UV detector / Vis 486, Pump 510): column: Lichrospher C18 (5 μm) t.a. eluent: H20 / CH3CN / dioxan 75/20/5 Heptan sodium sulfonate (20 mMol) pH 3. 0 with H3P04 flow rate 1 mL / min UV detector (245 nm) t. r. 12 min purity by CLAP (area%) = 99.586%; see Figure 4, peak # 3 Analysis of ^ -RMN (Brucker spectrometer of 200 MHz, chemical shifts (d) are reported in parts per million downstream of the internal Me4Si standard). (d; D20) 3.30 (m, 4H); 3.70 (m, 4H); 6.05 (s, 4H); 7.05 (s, 2H); 7.70 (d, 1H); 8.70 (d, 1H); 8.95 (s, 1H).

TREATMENT The compounds of the present invention can be used as active ingredients of therapeutic compositions to induce regression and / or variation of cancers in mammals when administered in amounts ranging from about 1 mg to about 0.4 g / kilogram of body weight. A preferred dosage regimen could be from about 1 mg to about 50 mg per kilogram of body weight per day. A unit dose may be employed so that about 70 mg to about 3.5 g of the active compound are administered to a subject of about 70 kg of body weight in a 24 hour period. The dose can be adjusted to be compatible with other treatment regimens, such as radiation therapy. The pharmaceutical compositions may be in the form of tablets, capsules, gel capsules, suppositories, lyophilized powders, and solutions for intravenous administration.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following:

Claims (10)

1. A method for the synthesis of 6,9-bis [(2-a-inoethyl) amino] benzo [g] isoquinoline-5,10-dione with a purity greater than 99%, which method is characterized in that it comprises: a) a a warm solution (55 ° C) of ethylenediamine in THF, drip 6,9-difluorobenzo [g] isoquinoline-5,10-dione added over a period of 2.5 hours; b) stir the mixture for 3 hours at the same temperature and gradually form a blue precipitate; c) after one night of stirring at 25 °, filter the suspension under a stream of nitrogen, wash with THF and dry under vacuum to give 6,9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline- 5, 10-dione as the difluorohydrate salt; d) directly dissolving the crude product in a mixture of water and AcOH to obtain a dark blue solution, whose pH is about 5, which is filtered on a glass fiber filter; e) gradually treat the filtered solution at room temperature with a filtered aqueous solution of maleic acid to 3M to reach a pH of 3.5; f) after about 30 'at 40 ° C, stir the suspension overnight at room temperature; g) washing the blue precipitate with additional water and EtOH, then drying under vacuum to give the crude 6, 9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5,10-dione dimaleate; h) suspend the crude dimaleate salt in water / - 'and heat at 50 ° C for 30'; 10 i) after one night of stirring at 25 ° C, filter the solution again, wash the blue precipitate with additional water and suspend this wet material in water and store with stirring at room temperature for about 40 h; 15 j) filter the dimaleate salt, wash with additional water, EtOH and then dry under vacuum, to produce the dimaleate of 6,9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5,10-dione .

2. A method for the synthesis of 6,9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5,10-dione with a purity greater than 99%, which method is characterized in that it comprises: a) add trifluoroacetic acid to a Suspension of 6,9-bis [(2-N-tert-butoxycarbonylaminoethyl) • • amino] benzo [g] isoquinoline-5,10-dione in methylene chloride; b) after stirring for approximately 16 hours at room temperature, dilute the mixture of 5 reaction with KOH and concentrate under vacuum; c) dilute the residual oil again with ethanol and concentrate again to a small volume; d) add demineralized water to the oily residue and adjust the pH to 4.2 units with aqueous KOH at twenty%; e) filtering the dark blue solution obtained on a glass fiber filter and mixing with an aqueous solution of 3M maleic acid; 5 f) readjust the pH of the solution to 3.4 units with 20% KOH and stir the mixture at room temperature for about 40 hours; g) collect the crude maleate by filtration and resuspend the demineralized water, heat at 50 ° C for 1 hour and store with agitation for an additional 16 hours at room temperature; h) filter the dark blue solid, wash with water and ethanol and dry under vacuum to yield the dimaleate salt of 6,9-bis [(2-aminoethyl) amino] enzo [g] iso-quinolin-5, 10- diona

3. An improved method for the synthesis of 6,9-difluorobenzo [g] isoquinoline-5, 10-dione, the method is characterized in that it comprises the steps of: a) heating a solution "of the mixture of acid 4- (2 ') , 5'-difluorobenzoyl) nicotinic acid and 3- (2 ', 5' - (difluoroben> zoil) isonicotinic acid in H2SO, t, fuming at 20% at 140 C: b) after approximately 30 minutes, add more acid sulfuric fuming at 20% to the hot reaction mixture in 4 portions, every 20 minutes; c) twenty minutes after the last addition, cool the reaction mixture to about 80 ° C and pour over demineralized water with ice; d) adjust the pH of the cold reaction to 1 with 40% NaOH and form a brown yellow precipitate; e) after about 1 hour at 0-5 ° C, filter the crude precipitate and dry under vacuum to give crude 6,9-difluorobenzo [g] isoquinoline-5,10-dione; f) dissolving the crude reaction product in boiling THF and decolorizing the hot solution with activated charcoal, filtering and concentrating; and g) after cooling to 0-5 ° C for about 2 hours collecting the yellow solid by filtration to obtain analytically pure 6,9-difluorobenzo [g] isoquinino-5, 10-dione.

4. The compound 6,9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5,10-dione or a physiologically acceptable salt thereof, characterized in that it has a purity greater than 97%.

5. The compound according to claim 4, characterized in that it has a purity greater than 99%.

6. A pharmaceutical composition, characterized in that it comprises the compound according to claim 4 and a pharmaceutically acceptable excipient.

7. The compound according to claim 4, characterized in that none of the impurities it contains exceed 0.5%.

8. The compound according to claim 4, characterized in that none of the unknown impurities it contains exceed 0.2%.

9. The compound according to claim 4, characterized in that it is a dimaleate salt.

10. The compound according to claim 5, characterized in that it is a dimaleate salt. A BETTER METHOD OF SYNTHESIS FOR 6,9-BIS [(2-AMINOETIL) AMINO1BENZO [g] ISOQUINOLIN ~ 5,10-DIONA AND ITS SALTS OF DIMALEATE SUMMARY OF THE INVENTION In the investigation of novel anthracene heteroanalogues, the dimaleate salt of 6,9-bis [(2-aminoethyl) amino] benzo [g] isoquinoline-5,10-dione (BBR 2778), was selected as the most promising. The novel methods of synthesis produce a compound with a purity greater than 99%.