HK1010051B - Ellipticine derivatives with antitumor activity - Google Patents

Description

The present invention relates to new ellipticin compounds, their preparation process and the pharmaceutical compositions containing them. The compounds of the present invention have an interesting therapeutic use due to their anti-tumor activity.

Derivatives of the ellipticin family are already known for their anticancer properties, such as the EP-A-42348 patent, which investigated olivacin compounds, and EP-A-393575 and EP-A-10029 which describe pyrido[4,3-b]carbazoles or ellipticin derivatives.

The needs of the therapeutic require the constant development of new anticancer drugs with the aim of obtaining molecules that are both more active and better tolerated.

The present invention relates to ellipticin derivatives with an originality compared to the compounds described in the previous art. The intensity of pharmacological properties, i.e. the antitumor activity of the products of the invention, was optimized by grafting an aminoalkyl-aminocarbonyl group at position 1 onto the 6H-pyrido[4,3-b]carbazole.

Furthermore, the compounds of the present invention are distinguished by their higher cytotoxicity in vitro and better activity in vivo compared to the reference products.

In particular, the present invention relates to molecules of general formula (I): in which: R1 is the radical in which: n is an integer between 1 and 6,R, identical or different R' and R6 are chosen independently from each other from hydrogen and a linear or branched alkyl radical containing 1 to 6 carbon atoms, possibly substituted by one or more hydroxy groups,or R and R' together with the nitrogen atom to which they are attached form a heterocycle possibly containing a second heterocycle, which heterocycle may be substituted by one or more linear or branched alkyl radicals containing 1 to 6 carbon atoms,and R6 is as defined above,either R and R6 together form a heterocycle substituted or not by one or more linear or branched alkyl radicals containing 1 to 6 carbon atoms,and R' is as defined above,R2 is a linear or branched alkyl radical containing 1 to 6 carbon atoms,R3, R4 and R5 identical or different are chosen independently from each other from hydrogen and a linear or branched alkyl radical containing 1 to 6 carbon atoms, their optical isomers and any N-oxides and salts of addition to an acid or base,pharmaceutically acceptable.

The most commonly used heterocycles are pyrrole, pyrrolines, pyrrolidine, imidazole, imidazolines, imidazolidine, pyrazole, pyrazolines, oxazole, oxazolines, oxazolidine, pyridine, piperidine, pyridazine, pyrimidine, pyrazine, piperazine, morpholine and thiomorpholine.

The invention also extends to the process of preparation of compounds of formula (I) characterized by a first biomimetic reaction by Besselievre Husson (Tetrahedron, (1981), 37, 241-246) in which a compound of formula (II) is reacted in an acidic medium, e.g. in acetic acid, with a compound of formula (III): where R2 and R5 have the same meanings as in formula (I) and R'4 is a linear or branched alkyl radical containing 1 to 6 carbon atoms, to obtain, after debenzylation and subsequent heating in the presence of dialkyloxalate, a compound of formula (IV) where R2, R'4 and R5 have the same meanings as before and R0 represents an alkyl group containing 1 to 5 carbon atoms,- What? which, by means of a reflux heating process in the presence of POCl3 in toluene, allows cyclization, to lead after dehydrogenation on palladium carbon with the compound formula (Va): where R0, R2, R'4 and R5 have the same meanings as before, whether or not containing by weight more than 0,5% of carbon where R'3 is a linear or branched alkyl radical containing 1 to 6 carbon atoms, in a polar solvent such as dimethylformamide, in the presence of an alkaline carbonate such as potassium carbonate and a crown ether, to obtain a compound with formula (Vb): wherein R2,R'3, R'4, R5 and R0 have the same meanings as before, Compounds of formula (Va) and (Vb) forming the set of compounds of formula (V): where R2, R3, R'4, R5 and R0 have the same meanings as before, compounds of formula (V) which are subjected to a substitution reaction by a compound of formula (VI): where R, R', R6 and n have the same meanings as in formula (I), For the preparation of compounds of formula (Ia): where R1, R2, R3, R'4 and R5 have the same meanings as before, a purity by weight of 99,99% or more but not more than 99,99%such as boron tribromide, to give the compounds with the formula (Ib): where R1, R2, R3 and R5 have the same meanings as before, Composed of formulae (Ia) and (Ib) forming the set of compounds of general formula (I), purified where necessary by a conventional separation technique and transformed, if necessary, into their pharmaceutically acceptable N-oxides and salts of addition to an acid or base.

The dealkylation reaction described for the transformation of the compound of formula (Ia) into compound of formula (Ib) can also be performed directly on the ester of formula (V) described above, so as to obtain the compound of formula (V') : in which R2, R3, R5 and R0 are as described above, which is then processed by the previously defined formula (VI) compound under the same operating conditions as those defined for the formula (V) compound, to lead to the previously defined formula (Ib) compound.

The formula (I) compounds have interesting pharmacological properties, and besides being more cytotoxic in vitro, they are more effective and at least as active in vivo as the reference compounds.

In addition, the compounds described in the present invention are active at very low doses and give many survivors at optimal doses, and therefore have an excellent therapeutic index.

Their ability to intersperse in DNA and cause cuts by inhibiting topoisomerases has found therapeutic use as anti-cancer agents.

The present invention also covers pharmaceutical formulations containing the products of formula (I), their N-oxides, optical isomers or one of their salts of addition to a base or acid, which are pharmaceutically acceptable, alone or in combination with one or more inert, non-toxic excipients or vehicles.

The pharmaceutical formulations of the invention shall include in particular those for oral, parenteral, nasal, rectal, perlingual, ocular or respiratory administration, including single or double-blind tablets, sublingual tablets, sachets, packets, capsules, glossets, tablets, suppositories, creams, ointments, dermal gels, injectable or oral preparations, aerosols, eye or nasal drops.

The effective dose varies with age and weight, route of administration, nature of indication and associated treatments and ranges from 0.1 to 400 mg daily in one or more doses.

The following examples illustrate the invention: The starting products are known or prepared from known operating methods.

Preparation of 2-β-Benzylamino)ethyl-6-methoxy-1-methylcarbazole

5-Methoxy-Indol and 1-benzyl-4-(1,1-ethylene dioxyethyl)-1,2,3,6-tetrahydropyridine (boiling point: 184-188°C at 10 mm Hg, obtained by reduction to sodium borohydride of 1-benzyl-4-(1,1-ethylene dioxyethyl) pyridinium chloride in methanol) are heated at 50 per cent reflux for 66 hours in acetic acid. The mixture is then heated in 2 litres of water. After extraction by dichloromethane and solvent, a volatile residue is obtained, which is then gradually recovered in ethylene acetate. The solid crystals are gradually filtered and formed into the minimum necessary acetone base to give the corresponding dichloromethane. Melting point: 150 °C

The following is added to the list of active substances: Stage A: 1-Methyl-2-[β-ethoxalamido) ethyl]-6-methoxycarbazole

35.6 g (88 mmol) of 2-[β-benzylamino) ethyl]-6-methoxy-1-methyl carbazole (as acetate) is dissolved in 400 ml of acetic acid to which 10 g of charcoal with 10% palladium is added. The mixture is heated to 50°C and stirred under normal pressure hydrogen, maintaining the temperature until the theoretical volume of hydrogen is consumed (10 hours); the solvent is evaporated at reduced pressure and the resulting residue is recovered in 200 ml of water. After filtration and addition of ammonia, the solid is air-dried and recrystallized in toluene. 18,16 g of beige crystals are obtained. The efficiency of the process is 81.4% melting point: 167-168°C

The solid is heated to 100-110°C in 70 ml of diethyl oxalate for 1 hour and the resulting mixture is evaporated dry. The solid residue is picked up in cyclohexane, filtered and recrystallized in ethyl acetate to give 23.92 g of the expected product. The yield: 94.6% Melting point: 144 ° C - What?

	C %	H %	N %
calculé	67,78	6,26	7,91
trouvé	67,96	6,35	8,21

Stage B: 1-(3,4-Dihydro-9-methoxy-5-methyl-6H-pyrido[4,3-b]carbazolyl) ethyl carboxylate

The solution is filtered and adjusted to pH 9-10 by adding sodium carbonate. The resulting solid is washed with water, dried and recrystallized in ethyl acetate. 2.36 g of yellow crystals are obtained. The yield: 70% Melting point: 233 to 34 °C - What?

	C %	H %	N %
calculé	71,41	5,99	8,33
trouvé	71,39	5,81	8,11

Stage C: 1-(9-Methoxy-5-methyl-6H-pyrid[4,3-b]carbazolyl) ethyl carboxylate

The remaining residue is extracted by 1N hydrochloric acid, the aqueous solution being neutralized by sodium bicarbonate. The resulting precipitate is extracted with dichloromethane. After evaporation of the solvent, the remaining solid residue is purified by chromatography on silica gel. The resulting crystallization is conducted by dichloromethane in yellow traces of ethylene. The resulting precipitate is produced by a mixture of dichloromethane and ethylene glycol. The yield was 58.3% Melting point: 255 °C - What?

	C %	H %	N %
calculé	71,84	5,43	8,38
trouvé	71,75	5,54	8,45

Stage D: 1-(5,6-Dimethyl-9-methoxy-6H-pyrido[4,3-b]carbazolyl) ethyl carboxylate

A mixture of 334 mg (1 mmol) of the ester obtained at the previous stage, 250 mg of dry potassium carbonate finely pulverized, 5 ml of dimethyl carbonate, 1 ml of dimethylformamide and 1 drop of 18C6 crown ether is heated at low reflux under agitation for 8 hours. After dry evaporation, the residue is recovered in water. The resulting solid is air-dried and recrystallized in cyclohexane. 270 mg of yellow crystals are obtained. Profitability: 77.5% Melting point: 162-164 °C - What?

	C %	H %	N %
calculé	72,39	5,79	8,04
trouvé	72,16	5,91	8,03

The substance is classified as a substance of very high concern in the Union for the assessment of the safety of the Union's fishing fleet.

348 mg (1 mmol) of the ester obtained in the previous step is heated in 5 ml of N,N-dimethyl-1,2-diaminoethane for 18 hours. The excess amine is evaporated at reduced pressure. The resulting residue is re-absorbed in water; the resulting solid is air-dried and recrystallized in cyclohexane. 234 mg of yellow crystals are obtained. The yield: 60 percent Melting point: 139 °C - What?

	C %	H %	N %
calculé	70,74	6,71	14,35
trouvé	70,53	6,96	14,35

The substance is classified as a substance of very high concern in the Union for the assessment of the safety of the food and feed.

390 mg (1 mmol) of the compound obtained at stage E is dissolved in 40 ml of dry dichloromethane under argon atmosphere. The solution is cooled to -70°C. 10 molar equivalents of boron tribromide, or 10 ml of a commercial 1M solution in dichloromethane, is added by drip. The mixture is allowed to return to room temperature (18 hours), then poured into 100 ml of ice water. The solution is adjusted to basic pH by adding triethylamine and then left to agitate at room temperature for 3 hours. The product is extracted from the dichloromethane and evaporated solvent to perform a chromatography on 164 crystals (dichloromethane evaporant/dichloromethane, acetylamine yellow). The final product is 95 mg of dichloromethane crystals which are obtained. Return on investment: 43.6% Melting point: 256 °C - What?

	C %	H %	N %
calculé	70,18	6,43	14,88
trouvé	69,79	6,69	14,49

The following is added to the list of active substances:

This compound is prepared according to the same protocol as described in Example 1 for stages A to D.

The substance is classified as a substance of very high concern in the Union for the assessment of the safety of the food and feed.

The heating time of the ester obtained at stage E is reduced to 8 hours and the diamine used is N,N-dimethyl-1,3-diaminopropane. The resulting product is extracted with dichloromethane; the solvent is then evaporated and the residue treated by an excess of maleic acid in the acetone to obtain the corresponding salt.

The substance is classified as a substance of very high concern in the Union for the assessment of the safety of the food and feed.

404 mg (1 mmol) of the amide obtained in the previous step is dissolved in 40 ml of dry dichloromethane under argon atmosphere. The solution is cooled to -70°C. 10 molar equivalents of boron tribromide are added drop by drop; the mixture is left at room temperature for 18 hours, then poured into 100 ml of ice water. The solution is made basic by adding triethylamine and agitated at room temperature for 3 hours. The product is extracted from dichloromethane. The yield: 76.8% Melting point: 198 °C - What?

	C %	H %	N %
calculé	69,15	6,81	14,02
trouvé	69,55	6,80	13,94

The following is added to the list of active substances:

This compound is prepared according to the same protocol as described in Example 1 except for step F. The yield: 60 percent Melting point: 139 °C - What?

	C %	H %	N %
calculé	70,74	6,71	14,35
trouvé	70,53	6,96	14,35

The following is the list of active substances which are to be used in the preparation of the product:

This compound is prepared according to the same protocol as described in Example 2 except for step F. The yield: 92.5% Melting point: 139 °C - What?

	C %	H %	N %
calculé	60,37	5,70	8,80
trouvé	60,28	5,62	9,03

The following is added to the list of active substances:

This compound is prepared according to the same protocol as described in Example 1, except for stages D and F which are deleted and the following changes to stage E: The amine used is N,N-dimethyl-1,3-diaminopropane,the solid,after drying, is recrystallized into ethyl acetate,Yield: 93 %Melting point: 206°C - What?

	C %	H %	N %
calculé	67,62	6,91	13,72
trouvé	67,60	6,72	14,05

The following is added to the list of substances which are to be used in the preparation of the product:

This compound is prepared according to the same protocol as described in Example 1 except for intermediate stage D and the following modifications to stages E and F: Stage E :-heating time reduced to 8 hours, Stage F :-the compound obtained after agitation for 3 hours at room temperature is insoluble in dichloromethane, it is filtered and recrystallized in ethyl acetate,Efficiency: 47% Melting point: > 270 °C - What?

	C %	H %	N %
calculé	69,59	6,12	15,46
trouvé	69,40	6,14	15,21

The following is added to the list of substances which are to be used in the preparation of the product:

This compound is prepared according to the same protocol as described in Example 1 except for the intermediate stage D and the following modifications:State E:-the amine used is N,N-dimethyl-1,3-diaminopropane, -the resulting solid is air-dried and recrystallized in ethyl acetate,State F:-the product obtained after 3 hours of agitation is filtered and recrystallized in ethyl acetate,Efficiency: 56% Melting point: 218 °C - What?

	C %	H %	N %
calculé	68,57	6,49	14,55
trouvé	68,45	6,43	14,86

The following is added to the list of active substances:

This compound is prepared according to the same protocol as described in Example 1, except for stages D and F and the following modification at stage E: Stage E:Heating time reduced to 8 hours.Efficiency: 88% Melting point: 215 °C - What?

	C %	H %	N %
calculé	68,57	6,49	14,54
trouvé	68,64	6,53	14,48

The following is added to the list of active substances:

This compound is prepared according to the same protocol as described in Example 1, except for the D and F stages which are removed and the amine used in stage E which is 2- ((pyrrolidin-1-yl)-1-aminoethane.

The following is added to the list of active substances:

This compound is prepared according to the same protocol as described in Example 6 using 2- ((pyrrolidine-1-yl)-1-aminoethane at step E.

The following is the list of active substances which are to be classified in the Annex to Regulation (EC) No 1907/2006 as substances with a specific chemical activity: Stage A: 1-(5,6-Dimethyl-9-hydroxy-6H-pyrido[4,3-b]carbazolyl)ethyl carboxylate

The ester obtained at step D of example 1 is engaged in the demethylation reaction described at step F of example 1 to yield 1-ethoxycarbonyl-5,6-dimethyl-9-hydroxy-6H-pyrid[4,3-b]carbazole.

The substance is classified as a non-phospholipid and is classified as a non-phospholipid.

0,4 g (1,198 mO) of the ester obtained in the previous step is dissolved in 10 ml of 2- (2-aminoethylamino) ethanol under argon atmosphere.

The unreacted amine is removed by vacuuming, the reaction medium is then added with water and dichloromethane. The usual treatment of the organic phases provides an oily residue which, taken up with ethanol, is then poured onto an ethanol solution saturated with hydrochloric acid gas. The yield is 97%. - What?

	C %	H %	N %	Cl %
calculé	52,70	6,03	11,17	14,14
trouvé	52,55	5,79	10,98	17,37

The following is added to the list of active substances:

0,47 g (1,407 mmol) of the ester obtained in step A of sample 11 is dissolved in 9 ml of 1,4-diaminobutan, under argon atmosphere.

The excess unreacted amine is removed by vacuuming and the reaction medium is then added to water and dichloromethane.

The majority of the insoluble product is isolated by excretion and dried; the other part is obtained by extraction with dichloromethane which is dried on magnesium sulfate, filtered and then evaporated dry. Profitability: 62% The melting point is > 95 °C (decomposition). - What?

	C %	H %	N %
calculé	67,60	6,60	14,33
trouvé	67,85	6,98	13,02

The following is added to the list of active substances:

0,4 g (1,198 mmol) of the ester obtained in step A of sample 11 are dissolved in 7,5 ml of 1- ((2-aminoethyl) pyrrolidine under argon atmosphere.

The excess amine is removed by vacuuming and the reaction medium is hydrolysed. The efficiency of the process is: 65% Melting point: > 120°C (decomposition) - What?

	C %	H %	N %
calculé	66,03	6,97	12,84
trouvé	65,99	7,11	12,27

The following is added to the list of active substances:

0,36 g (1,078 mmol) of the ester obtained at step A of sample 11 is dissolved in 10 ml of 4- (3-aminopropyl) morpholine under argon atmosphere.

The reaction medium is hydrolyzed and taken back to dichloromethane. The mixture is left to agitate for about 1 hour. Most of the insoluble product is isolated by excretion and dried. The other part is extracted from dichloromethane which is dried on magnesium sulfate, filtered and evaporated dry. The entire product is recrystallized in absolute ethanol to give 0.42 g of yellow crystals corresponding to the expected product. The yield: 90 per cent Melting point: 110 °C - What?

	C %	H %	N %
calculé	69,42	6,53	12,95
trouvé	69,34	6,50	12,86

The following is added to the list of substances which are to be used in the preparation of the product: The substance is classified as a substance of very high concern in the Union for the assessment of the safety of the use of the active substance.

5 g (15 mmol) of the ester obtained at step C of example 1, dissolved in 10 ml of dimethylformamide, are added 142 ml of diethyl carbonate, 3.75 g of potassium carbonate and 200 mg of 18C6 crown ether under argon atmosphere. The mixture is heated at 130-140 °C for 6 days and then concentrated. After addition of water and extraction with dichloromethane, the usual treatment of the organic phase yields 4.11 g of yellow crystals. (recrystallization solvent: toluene). The yield: 76 percent Melting point: 149 °C - What?

	C %	H %	N %
calculé	72,91	6,12	7,73
trouvé	73,06	6,19	7,72

The substance is classified as a substance of very high concern in the Union for the assessment of the safety of the food and feed.

The mixture is agitated for 2 hours 30 minutes at -78°C and then 1 hour at room temperature. The excess boron tribromide is hydrolyzed by a drop of water, maintaining the temperature at around 0°C. The solution is maintained for 1 hour under precipitation after alkalization by an ammonia solution. The precipitate is isolated and dried and the organic phases are recombined. The usual raw set is produced in gristalline to provide the expected treatment of 2,98 g of toluene. The yield: 78% Melting point: 260 °C - What?

	C %	H %	N %
calculé	72,40	5,79	8,04
trouvé	72,94	5,99	7,93

The substance is classified as a substance of very high concern in the Union for the purposes of the control of the presence of the substance in the Union.

The mixture formed by 0.8 g (2,30 mmol) of ester obtained in the previous step in 12 ml of N,N-dimethylaminoethylene diamine under argon atmosphere is heated to 115°C for 36 hours.The medium is then hydrolysed and extracted to dichloromethane and the organic phase is dried on magnesium sulphate and then filtered.

After the dichloromethane has been evaporated, the oily residue is purified by silica gel chromatography (dichloromethane/ethanol 9:1 and approximately 0.5% triethylamine) to obtain 0.424 g of yellow crystals corresponding to the expected product. Profitability: 44 percent The melting point is > 115 °C (decomposition). - What?

	C %	H %	N %
calculé	66,17	7,00	13,42
trouvé	66,01	6,81	13,41

Pharmacological study

The following examples show that the therapeutic index of the best compounds of the invention is excellent: They are cytotoxic, active from doses below 5 mg/kg and up to 30 to 60 mg/kg, and give many survivors at optimal doses.

Example A: Cytotoxicity of reference compounds and products

Seven cell lines were used: 2 murine leukemias, L1210 and P388;1 human squamous cell carcinoma, KB-3-1, and a human lung carcinoma S1; the corresponding resistant lines, KB-A1 whose multidrug resistance was induced by Adriamycin (ADR) on KB-3-1, P388/VCR-20 whose multidrug resistance was induced by Vincristine (VCR) on P388; and S1/tMDR whose multidrug resistance was obtained by transfecting the human MDR1 gene into S1 cells.

The cells are cultured in complete RPMI 1640 culture medium containing 10% foetal calf serum, 2 mM glutamine, 50 units/ml penicillin, 50 μg/ml streptomycin and 10 mM Hepes.

The cells are then divided into microplaques and exposed to cytotoxic compounds. The cells are then incubated for approximately 4 doubling times, i.e. 2 days (P388, P388/VCR-20 and L1210) and 4 days (KB-A1, KB-3-1, S1 and S1/tMDR). The number of viable cells is then quantified by a colorimetric assay, the Microculture Tetrazolium Assay (Carmichael J., DeGraff W.G., Gazdar A.F., Minna J.D. and Mitchell J.R., Evaluation of a tetrazolium-based semiautomated colorimetric assay: assessment of chemosensitivity testing, Cancer Res., 47, 936-942, 1987). The results expressed in IC50 are obtained in the following table: - What?

The results show that the products in examples 1, 2 and 6 are approximately 9 times more cytotoxic than adriamycin and 46 times more than ellipinium acetate.

Example B: Cytotoxicity of reference compounds and products on lines with multidrug resistance (MDR) phenotype

The resistance factor is defined by the following: $\frac{{\text{IC}}_{\text{50}}\text{lignée résisistante}}{{\text{IC}}_{\text{50}}\text{lignée sensible}}$

Cross-resistance of ADR-resistant lines is much lower than that of adriamycin. The activity of the compounds is much higher than that of either adriamycin or ellipinium acetate on KB-A1. Resistant lines P388/VCR-20 and S1/tMDR (which have lower ADR resistance) are more sensitive to examples 1 and 6 than the corresponding susceptible lines. These derivatives could therefore be used against adriamycin-resistant tumors.

The following is a list of the activities of the laboratory: Example C-1: Anti-tumor activity of the compounds on leukaemia P388

The P388 (mouse leukemia) line was provided by the National Cancer Institute (NCI) (Frederick, USA). Tumor cells (106 cells) were inoculated on day 0 into the peritoneal cavity of female BDF1 mice (Iffa-Credo, France). Eight to ten mice, weighing between 18 and 20 g, were used per experimental group.

The products were administered on Day 1 at the indicated intraperiotonal doses.

The anti-tumor activity is expressed as % of T/C: $\text{\% T/C =}\frac{\text{Temps de survie médian des animaux traités}}{\text{Temps de survie médian des animaux contrôles}}\text{x 100}$

Animals surviving 60 days (long-term survivors) are indicated.

The results are given in Table 3 below: - What?

The weight variation at the optimal dose used for derivatives is -0.4 to -0.7 g whereas it is -0.7 g for adriamycin and -4 g for ellipthinium acetate.

The compounds are active at 5 mg/kg, with all doses used giving long-term survivors for two derivatives (examples 1 and 6 in Table 2). The product in example 1 used in a single administration at 30 mg/kg cured 7 of 10 treated mice whereas adriamycin cured only 2 and ellipinium acetate none. The three derivatives tested were significantly more active than ellipinium acetate which is also toxic at 5 mg/kg.

Example C-2: Anti-tumor activity of the compounds on Lewis lung carcinoma

Lewis lung carcinoma (provided by NCI, Frederick, USA) was grafted as fragments to OL and subcutaneously to female B6D2F1 mice weighing 18 to 20 g. The products were administered at the doses indicated intravenously at J3, J6 and J9. Anti-tumor activity was determined at J20 by measurement of tumor volume: $\text{T/C \% (volume) =}\frac{\text{volume tumoral médian des animaux traités}}{\text{volume tumoral médian des animaux témoins}}\text{x 100}$ The long-term survivors (J90) are noted. $\text{T/C \% (survie) =}\frac{\text{temps médian de survie des animaux traités}}{\text{temps médian de survie des animaux témoins}}\text{x 100}$ The compound in example 1 is very active on this highly resistant model. e dose of 40 mg/kg is curative in 100% of the animals whereas adriamycin, at the maximum tolerated dose, is much less active (Table 4). - What?

Example C-3: Anti-tumor activity of the compounds on sarcoma M5076

The sarcoma M5076 is provided by the NCI (Frederick, USA).Tumor cells (107 cells/animal) were injected at J0 in the peritoneal cavity of female B6D2F1 mice.The products were administered intravenously at J1, J5, J9 and J13 at the indicated doses.Survival of the animals was noted at J90 and survival T/C (%) was calculated. The compound in example 1 at a dose of 20 mg/kg is very active on this tumour. 6 out of 10 survivors are observed at J90. - What?

Example C-4: Anti-tumor activity of the compounds on the colon 38

Colon 38 (provided by NCI, Frederick, USA) was grafted as subcutaneous fragments to female B6D2F1 mice. The products were administered intravenously at J2 and J9 and antitumor activity was determined at J25 by measurement of tumor volume (T/C volume, %). The compound in example 2 administered intravenously is very active on this solid tumour at the dose of 20 mg/kg (T/C = 0 %) (Table 6). It is as active as 5-fluorouracil (5-Fu) used at the dose of 80 mg/kg.

Claims (9)

1. Compounds of the general formula (I) : wherein :

   R₁ represents the group in which :

   - n is an integer of from 1 to 6,

   - R, R' and R₆, which are the same or different, are selected, independently of one another, from hydrogen and a straight-chain or branched alkyl radical containing from 1 to 6 carbon atoms optionally substituted by one or more hydroxy groups,

   - or R and R', together with the nitrogen atom to which they are attached, form a heterocycle optionally containing a second hetero atom, which heterocycle may be substituted by one or more straight-chain or branched alkyl radicals containing from 1 to 6 carbon atoms, and R₆ is as defined above,

   - or R and R₆ together form a heterocycle which is unsubstituted or substituted by one or more straight-chain or branched alkyl radicals containing from 1 to 6 carbon atoms, and R' is as defined above,

   - R₂ represents a straight-chain or branched alkyl radical containing from 1 to 6 carbon atoms,

   - R₃, R₄ and R₅, which are the same or different, are selected, independently of one another, from hydrogen and a straight-chain or branched alkyl radical containing from 1 to 6 carbon atoms,

   their optical isomers and also their possible N-oxides and pharmaceutically acceptable addition salts with an acid or base.
2. Compound according to claim 1 which is 1-(N,N-di-methylaminoethylaminocarbonyl)-5,6-dimethyl-9-hydroxy-6H-pyrido[4,3-b]carbazole, its N-oxides and also the pharmaceutically acceptable addition salts thereof with an acid.
3. Compound according to claim 1 which is 1-(N,N-di-methylaminopropylaminocarbonyl)-5,6-dimethyl-9-hydroxy-6H-pyrido[4,3-b]carbazole, its N-oxides and also the pharmaceutically acceptable addition salts thereof with an acid.
4. Compound according to claim 1 which is 1-(N,N-di-methylaminoethylaminocarbonyl)-5-methyl-9-hydroxy-6H-pyrido[4,3-b]carbazole, its N-oxides and also the pharmaceutically acceptable addition salts thereof with an acid
5. Compound according to claim 1 which is 1-[N-(3-morpholinopropyl)aminocarbonyl]-5,6-dimethyl-9-hydroxy-6H- pyrido[4,3-b]carbazole, its N-oxides and also the pharmaceutically acceptable addition salts thereof with an acid.
6. Compound according to claim 1 which is 1-[N-(2-pyrrolidin-1-ylethyl)aminocarbonyl]-5,6-dimethyl-9-hydroxy-6H-pyrido[4,3-b]carbazole, its N-oxides and also the pharmaceutically acceptable addition salts thereof with an acid.
7. Process for the preparation of compounds of formula (I), characterised by a first reaction in which a compound of formula (II) is reacted in acetic acid with a compound of formula (III):    wherein R₂ and R₅ are as defined for formula (I) and R'₄ represents a straight-chain or branched alkyl radical containing from 1 to 6 carbon atoms, to obtain, after debenzylation followed by heating in the presence of a dialkyl oxalate, a compound of formula (IV) :    wherein R₂, R'₄ and R₅ are as defined hereinbefore and R₀ represents an alkyl radical containing from 1 to 5 carbon atoms, which may be cyclised by heating at reflux in the presence of POCl₃ in toluene so as to yield, after dehydrogenation on palladium-on-carbon, a compound of formula (Va) :    wherein R₀, R₂, R'₄ and R₅ are as defined hereinbefore, if desired, the 6-nitrogen atom of the carbazole of which is substituted by treatment with a dialkyl carbonate of formula    wherein R'₃ represents a straight-chain or branched alkyl radical containing from 1 to 6 carbon atoms, in a polar solvent, in the presence of an alkali metal carbonate, to obtain a compound of formula (Vb) :    wherein R₂, R'₃, R'₄, R₅ and R₀ are as defined hereinbefore, the compounds of formulae (Va) and (Vb) forming the totality of the compounds of formula (V) :    wherein R₂, R₃, R'₄, R₅ and R₀ are as defined hereinbefore, which compounds of formula (V) are subjected to a substitution reaction with a compound of formula (VI) : wherein R, R', R₆ and n are as defined for formula (I), to obtain compounds of formula (Ia) :    wherein R₁, R₂, R₃, R'₄ and R₅ are as defined hereinbefore, which compounds of formula (Ia) may be dealkylated by the addition of a boron trihalide to yield compounds of formula (Ib) :    wherein R₁, R₂, R₃ and R₅ are as defined hereinbefore, the compounds of formula (Ia) and (Ib) forming the totality of the compounds of the general formula (I) which, if necessary, are purified according to a conventional separation technique and, if necessary, are converted into their possible N-oxides and into their pharmaceutically acceptable addition salts with an acid or base.
8. Pharmaceutical compositions comprising as active ingredient at least one compound according to any one of claims 1 to 6, alone or in combination with one or more inert, non-toxic, pharmaceutically acceptable excipients or carriers.
9. Pharmaceutical compositions according to claim 8 comprising at least one active ingredient, an anti-tumour agent inhibiting topoisomerases, according to any one of claims 1 to 6, for use in the treatment of cancers.