GB1589539A

GB1589539A - Naphthacene derivatives and their salts

Info

Publication number: GB1589539A
Application number: GB5252877A
Authority: GB
Original assignee: INST INT PATHOLOGIE CELLULAIRE
Current assignee: INST INT PATHOLOGIE CELLULAIRE
Priority date: 1976-12-20
Filing date: 1977-12-16
Publication date: 1981-05-13
Also published as: DE2756604A1

Description

(54) IMPROVEMENTS IN OR RELATING TO NAPHTHACENE DERIVATIVES AND THEIR SALTS (71) We, INSTITUT INTERNATIONAL DE PATHOLOGIE CELLU LAIRE ET MOLECULAIRE, à Belgian Association of, 75, Avenue Hippocrate a Bruxelles, Belgium, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and ;by the following statement: The present invention relates to novel naphthacene derivatives and their salts, thei.r preparation, and pharmaceutical compositions containing them.

According to a first aspect of the invention there is provided a naphthacene derivative or a salt thereof or an isomeric mixture thereof, the naphthacene derivative having the general formula:

wherein R is hydrogen or a hydroxy radical, Rl and R2, which are the same or different, each represent hydrogen or halogen or an alkyl radical containing 1 to 4 carbon atoms or R1 and R2 together form an alkylene radical containing 3 or 4 carbon atoms.

The halogen may for instance, be chlorine.

According to a second aspect of the invention there is provided a process for the preparation of the compound or compounds defined by the first aspect of the invention, the process comprising reacting an anhydride of the general formula:

wherein Rl and R2 are as defined above with a compound of the general formula:

and isolating the compound or compounds having the formula (I) from the reaction mixture and optionally converting the said compound(s) into salt(s).

The reaction is generally effected at a temperature between 10 and 30"C in an aqueous medium which may be buffered at a pH preferably between 7.5 and 9.

The reaction may be conducted in the presence of an organic solvent such as an alcohol (e.g. methanol, ethanol). The pH of the medium can Ibe kept at any desired value by adding a mineral base, e.g. sodium hydroxide, in the course of the reaction.

The compound 9f the general formula (III) in which R represents hydrogen is called daunorubicine or 9-acetyl-7-(3-amino-2,3,6-tridesoxy-L-lyxohexosyl)-5,12- dioxo- 6,9,11 -trihydroxy-4-methoxy-5,7,8,9, 10,1 2-hexahydronaphthacene. This product and its preparation have been described in Belgian Patent Specification No. 632,391.

The compound of the general formula (ITS) in which R represents a hydroxy radical is called adriamycine or 9 - hydroxyacetyl - 7 - (3 - amino - 2,3,6 - tridesoxy L - lyxohexosyl) - 5,12 - dioxo - 6,9,11 - trihydroxy - 4 - methoxy - 5,7,8,9,10,12- hexahydronaphthacene. This product and its preparation have been described in Belgian Patent Specification No. 713,773.

Daunorabicine and adriamycine possess remarkable antitumoral properties.

When the symbols R1 and R2 in the general formula CII) are different, products isomeric in position may be formed in the course of the reaction on the compound of the general formula (III). These isomeric products are also within the scope of the present invention.

The new products of the general formula (I) may optionally be purified by physical methods, such as chromatography. The new products according to the present invention may optionally be converted into metallic salts, into ammonium salts, or into addition salts with a nitrogenous base by application of methods known per se.

These salts can thus be obtained by the action of an alkali metal or alkaline earth metal base, ammonia, or an amine on a product of the general formula (I) in a suitable solvent, such as an alcohol, an ether, a ketone, or water. The salt formed precipitates out, possibly after concentration of its solution, and it may be separated by filtration or decanting. It may also be obtained by lyophilisation of its solution.

According to a third aspect of the invention there is provided a pharmaceutical composition comprising a naphthacene derivative having the general formula (I) or a salt thereof or an isomeric mixture thereof and at least one compatible and phar maceutically acceptable diluent or adjuvant therefor. The pharmaceutical composition may include at least one other physiologically active substance.

The products of the general formula (I) and their salts have remarkable antitumoral properties together with low toxicity.

The activity of the products according to the present invention is dependent on the pH of the medium in which they act. Thus, these products are stable and have low activity in a neutral or slightly basic medium, while their activity increases when the pH becomes acid. It is important to observe that in a living organism the pH of the normal cells is close to 7.2, while that of tumorous cells is close to 6. Consequently, the products of the general formula (I) can act selectively on tumorous cells without damaging normal cells.

We find that the new derivatives of naphthacene of the general formula (I) and their salts are particularly active on graftable tumours in the mouse in doses between 0.1 and 5 mg/kg administered intraperitoneally, on leukaemia L1210, leukaemia P388, and leukosarcomatosis.

Particular mention may be made of "N-citraconoyldaunorubicine" (formula (I): R = H; R1 = Cli,; R2 = H) whose toxicity in mice gives a 50% lethal dose (LD,,) of about 16 mg/kg i.p., the maximum tolerated dose being close to 6.25 mg/kg i.p.

In respect of leukaemia L1210 in the mouse this product has a DAl50 close to 1 mg/kg i.p. The product has a chemotherapeutic index (LD (,/DAlSo) close to 16, whereas under the same conditions that of daunorubicine is between 6 and 10.

The following examples show how the invention may be put into practice.

Example 1 - Preparation of N-citraconoyldaunorubicine (formula I: R = H; Rl = Cli,; R2 = H).

1.5 g of daunorubicine is dissolved in 15 cc of a 0.1 M phosphate buffer at pH 8.0. 0.8 cc of citraconic anhydride is then added thereto. The reaction medium is agitated for one hour at a temperature close to 20"C while keeping the pH close to 8.0 by adding 5N sodium hydroxide. After lyophilisation of the reaction medium, the residue is taken up in a mixture of 50 cc of chloroform and 25 cc of methanol.

The solution is filtered through a column of 80 g of silica, eluting with the chloroformmethanol mixture (2 - 1 by volume) and collecting fractions of 200 cc. Fractions 2 to 6 are concentrated to dryness under reduced pressure (25 mm mercury). The residue is taken up in 50 cc of water and the solution is lyophilised. 1.56 g of the sodium salt od 9-acetyl-7- (3 -citraconoylamino-2,3 ,6-tridesoxy-L-lyxohexosyl)-5, 12- dioxo-6,9,11 -trihydroxy-4-methoxy-5 ,7, 8,9,10,1 2-hexahydronaphthacene (or N-citraconoyldaunorubicine) are thus obtained in the form of an orange-red powder melting at 200 - 2010c with decomposition. Rf = 0.69 (silica gel; dichloromethane-methanolwater-formic acid (85-15-1-2 by volume)).

Example 2 -- Preparation of N-citraconoyl-adriamycine (formula I: R = OH; R1 = Cli,; R2 = H).

40 mg of adriamycine are dissolved in 10 cc of a 0.1 M phosphate buffer at pH 8.0. 50 o1 of citraconic anhydride and 1 cc of methanol are then added. The reaction medium is agitated for one hour at a temperature close to 200C, the pH being kept close to 7.5 by adding 1N sodium hydroxide. The solution is lyophilised and the residue taken up in 100 cc of methanol. The solution is filtered through a "Whatman" No. 42 paper. "Whatman" is a Trade Mark. After concentration of the filtrate to dryness under reduced pressure, 46 mg of the sodium salt of 9hydroxyacetyl - 7 - (3 - citraconoylamino - 2,3,6 - tridesoxy - L - lyxohexosyl) - 5,12dioxo- 6,9,11 - trihydroxy - 4 - methoxy - 5,7,8,9,10,12 - hexahydronaphthacene (or N - citraconoyl - adriamycine) are obtained in the form of an orange - red powder.

Rf = 0.59 (silica gel; dichloromethane-methanol-water-formic acid (85-15-1-2 by volume)).

Example 3 - Preparation of N-dimethylmaleoyldaunorubicine (formula I: R = H; R, = R2 = CH).

100 mg of daunorubicine are dissolved in 10 cc of 0.1 M phosphate buffer at pH 8.5 45 mg of dimethylmaleic anhydride are added slowly, while keeping the pH between 8 and 9 by adding 1N sodium hydroxide.

When the reaction has been completed, that is to say when the pH remains stable, the solution is lyophilised. The residue is taken up in 10 cc of a mixture of chloroform and methanol (1 - 1 by volume). The solution is filtered through 80 g of silica gel, eluting with a mixture of chloroform and methanol (1 - 1 by volume) and collecting fractions of 200 cc. Fractions 2 to 6 are combined and concentrated under reduced pressure (25 mm of mercury). 107 mg of the sodium salt of 9-acetyl-7 [3-(2,2-dimethyl-maleoyl) amino2,3;6-tridesoxy-L-lyxohexosylj -5,12-dioxo-6,9,11-tri- hydroxy-4-methoxy-5,7,8,9,10,12-hexahydro-naphthacene (or N-dimethylmaleoyldaunorubicine) are thus obtained in the form of an orange-red powder.

Rf = 0.18 (silica gel; chloroform-methanol-water-(120-20-1 by volume)).

Example 4 -- Preparation of N-(3,4,5,6,-tetrahydrophthaloyl-daunorubicine (formula I: R = H; R, and R2 together represent an alkylene radical containing 4 carbon atoms).

100 mg of daunorubicine are dissolved in 10 cc of a 0.1 M phosphate buffer at pH 8.5. 50 mg of 3,4,5,6-tetrahydrophthalic anhydride are added thereto. The mixture is agitated at a temperature close to 20"C for one hour, while maintaining the pH between 8 and 9 by adding N sodium hydroxide. The reaction medium is lyophilised and the residue taken up in 20 cc of choloroform. The solution is filtered through 80 g of silica gel, eluting with a mixture of chloroform and methanol (85 - 15 by volume) and collecting fractions of 200 cc. Fractions 2 to 6 are combined and concentrated to dryness under reduced pressure (25 mm mercury). 114 mg of the sodium salt of 9 - acetyl - 7 - [3 - (2 - carboxy - cyclohexene - 1 - yl)carbonylamino2,3,6 - tridesoxy - L - lyxohexosyl] - 5,12 - dioxo - 6,9,11 - trihydroxy - 4 - methoxy5,7,8,9,10,12 - hexahydronaphthacene or N - (3,4,5,6 - tetrahydro - phthaloyl) - daunorubicine are thus obtained in the form of an orange - red powder.

Rf = 0.38 (silica gel; chloroform-methanol-water(120-20-1 by volume)).

The compositions of the invention may be presented in any suitable form for the type of administration proposed. Parenteral administration is preferred, particularly intravenous administration.

The compositions of the invention for parenteral administration may be sterile aqueous or non-aqueous solutions, suspensions, or emulsions. Propylene glycol, polyethylene glycol, vegetable oils, particularly olive oil, and injectable organic esters, for example ethyl oleate, may be used as solvent or vehicle. These compositions may also contain adjuvants, particularly wetting, emulsifying, and dispersing agents.

Sterilisation may be effected in various ways, for example with the aid of a bacterio logical filter, by incorporating sterilising agents in the composition, by irradiation, or by heating. They may also be prepared in the form of solid sterile compositions which at the moment of use can be dissolved or dispersed in sterile water or any other injectable sterile medium.

The products of the general formula (I) and their salts are especially useful in the treatment of cancer with daily doses generally between 2 and 4 mg/kg administered intravenously for an adult.

The following example illustrates a composition according to the invention.

Example 5.

A solution is prepared containing 31 mg/cc of the sodium salt of 9 - acetyl - 7 (3 - citraconoylamino - 2,3,6 - tridesoxy - L - lyxohexosyl)S,12 - dioxo - 6,9,11 - tri hydroxy - 4 - methoxy - 5,7,8,9,10,12 - hexahydro - naphthacene (as prepared in Example 1) by dissolving 3.1 g of this product in physiological solute in a sufficient amount to make 100 cc. The solution obtained is distributed aseptically in ampoules at the rate of 5 cc per ampoule. The ampoules are sealed, each containing 150 mg of non - salified product.

WHAT WE CLAIM IS: 1. A naphthacene derivative or a salt thereof or an isomeric mixture thereof, the naphthacene derivative having the general formula:

wherein R is hydrogen or a hydroxy radical, Rl and R2, which are the same or different, each represent hydrogen or halogen or an alkyl radical containing 1 to 4 carbon atoms or Rl and R, together form an alkylene radical containing 3 or 4 carbon atoms.

2. A naphthacene derivative or a salt thereof or an isomeric mixture thereof according to Claim 1 substantially as herein described and exemplified.

3. A process for the preparation of the compound or compounds claimed in Claim 1, comprising reacting an anhydride of the general formula:

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. between 8 and 9 by adding N sodium hydroxide. The reaction medium is lyophilised and the residue taken up in 20 cc of choloroform. The solution is filtered through 80 g of silica gel, eluting with a mixture of chloroform and methanol (85 - 15 by volume) and collecting fractions of 200 cc. Fractions 2 to 6 are combined and concentrated to dryness under reduced pressure (25 mm mercury). 114 mg of the sodium salt of 9 - acetyl - 7 - [3 - (2 - carboxy - cyclohexene - 1 - yl)carbonylamino2,3,6 - tridesoxy - L - lyxohexosyl] - 5,12 - dioxo - 6,9,11 - trihydroxy - 4 - methoxy5,7,8,9,10,12 - hexahydronaphthacene or N - (3,4,5,6 - tetrahydro - phthaloyl) - daunorubicine are thus obtained in the form of an orange - red powder. Rf = 0.38 (silica gel; chloroform-methanol-water(120-20-1 by volume)). The compositions of the invention may be presented in any suitable form for the type of administration proposed. Parenteral administration is preferred, particularly intravenous administration. The compositions of the invention for parenteral administration may be sterile aqueous or non-aqueous solutions, suspensions, or emulsions. Propylene glycol, polyethylene glycol, vegetable oils, particularly olive oil, and injectable organic esters, for example ethyl oleate, may be used as solvent or vehicle. These compositions may also contain adjuvants, particularly wetting, emulsifying, and dispersing agents. Sterilisation may be effected in various ways, for example with the aid of a bacterio logical filter, by incorporating sterilising agents in the composition, by irradiation, or by heating. They may also be prepared in the form of solid sterile compositions which at the moment of use can be dissolved or dispersed in sterile water or any other injectable sterile medium. The products of the general formula (I) and their salts are especially useful in the treatment of cancer with daily doses generally between 2 and 4 mg/kg administered intravenously for an adult. The following example illustrates a composition according to the invention. Example 5. A solution is prepared containing 31 mg/cc of the sodium salt of 9 - acetyl - 7 (3 - citraconoylamino - 2,3,6 - tridesoxy - L - lyxohexosyl)S,12 - dioxo - 6,9,11 - tri hydroxy - 4 - methoxy - 5,7,8,9,10,12 - hexahydro - naphthacene (as prepared in Example 1) by dissolving 3.1 g of this product in physiological solute in a sufficient amount to make 100 cc. The solution obtained is distributed aseptically in ampoules at the rate of 5 cc per ampoule. The ampoules are sealed, each containing 150 mg of non - salified product. WHAT WE CLAIM IS:

1. A naphthacene derivative or a salt thereof or an isomeric mixture thereof, the naphthacene derivative having the general formula:

wherein Rl and R2 are as defined in Claim 1 with a compound of the general formula:

4. A process according to Claim 3, wherein the reaction is effected at a temperature between 10 and 30"C in an aqueous medium.

5. A process according to Claim 4, wherein the aqueous medium is buffered at a pH between 7.5 and 9.

6. A process according to Claim 5, wherein the aqueous medium is buffered at the required pH by addition of sodium hydroxide or other mineral base.

7. A process according to any one of Claims 3 to 6, which is conducted in the presence of an organic solvent.

8. A process according to Claim 7, wherein the organic solvent comprises an alcohol.

9. A process according to any one of Claims 3 to 8 substantially as herein described and exemplified.

10. A naphthacene derivative having the formula (I) or a salt thereof or an isomeric mixture thereof which has been produced by the process claimed in any one of Claims 3 to 9.

11. A pharmaceutical composition comprising a naphthacene derivative having the general formula (I) or a salt thereof or an isomeric mixture thereof and at least one compatible and pharmaceutically acceptable diluent or adjuvant therefor.

12. A pharmaceutical composition according to Claim 11, which is in the form of a sterile solution, suspension or emulsion for parenteral administration.

13. A pharmaceutical composition according to Claim 11, which is in the forn: of a solid composition to be dissolved or dispersed at the moment of use in sterile water or any other injectable sterile medium.

14. A pharmaceutical composition according to Claim 11 substantially as herein described and exemplified.