Novel, SUBSTITUTED N-BENZYL-INDOL-3-YL GLYOXYLIC ACID DERIVATIVES HAVING AN ANTI-TUMORAL EFFECT

Description of the invention

The subject of the invention are new, substituted N-benzylindol-3-ylglyoxylic acid derivatives with antitumor activity and their use

Indole-3-glyoxylamides have a wide variety of applications as pharmacodynamically active compounds and as synthetic building blocks in pharmaceutical chemistry.

In Dutch patent application 6502481, compounds with an anti-inflammatory, antipyretic and analgesic activity profile are described.

In British patent application GB-B 1028812, indolyl-3-glyoxylic acid derivatives and their amides are mentioned as analgesic, anticonvulsant and beta-adrenergic compounds.

G. Domschke et al. (Ber. 94, 2353 (1961)) describe 3-indolylglyoxylamides which have not been pharmacologically characterized.

E. Walton presented in J. Med. Chem., 11, 1252 (1968) indolyl-3-glyoxylic acid derivatives with inhibitory activity against glycerophosphate dehydrogenase and lactase dehydrogenase.

In EP 675110, 1H-indole-3-glyoxylamides have been tested as sPLA2 inhibitors, useful in the treatment of septic shock, in pancreatitis and in the treatment of allergic rhinitis and rheumatoid arthritis.

It has already been proposed in the German patent application No. 19814838.0 to use the compounds according to DE-A 19636150 A1 as antitumor agents.

The object of the invention is to provide novel compounds of the indol-3-ylglyoxylic acid series with good anti-tumor activity, which can be used in the preparation of anti-tumor agents.

The essence of the invention are new, substituted N-benzylindol-3-ylglyoxylic acid derivatives with antitumor activity, with the general formula 1

<img file="PL195014B1_D0001.tif" />

wherein the groups R, R1, R2, R3, R4 and Z are as follows:

R is a nitro group, amino group, NC (O) Ph group or NSO2PhMe group. R1 is hydrogen or benzyl R2 is the pyridine structure of formula 2

<img file="PL195014B1_D0002.tif" />

which pyridine structure is alternatively linked to carbon atoms 2, 3 and 4 of the ring and may be substituted with R5 and R6 being H,

R3 and R4 are hydrogen;

Z stands for O.

Preferably, the compound of formula 1 is N- (Pyridin-4-yl) - [1- (4-aminobenzyl) indol-3-yl] glyoxylamide (D-68838).

PL 195 014 B1

Preferably, the compound of formula 1 is N- (Pyridin-4-yl) - [1- (4-nitrobenzyl) indol-3-yl] glyoxylamide (D-68836).

In another aspect, the invention relates to mineral acids addition salts of compounds of general formula I, in particular hydrochloric acid.

In a further aspect, the invention relates to the use of the compounds of the invention for the preparation of anti-cancer agents.

In yet another aspect, the invention relates to the use of the compounds of the invention for the preparation of pharmaceutical compositions for the treatment of oncoses.

Compounds of formula 1 are prepared as shown in Scheme 1 below:

Scheme 1

Level 1

<img file="PL195014B1_D0003.tif" />

Level 1

The indole derivative, which may be unsubstituted or monosubstituted or multisubstituted at C-2 or on the phenyl ring, is dissolved in a protic, dipolar aprotic or non-polar organic solvent, such as e.g. isopropanol, tetrahydrofuran, dimethylsulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, dioxane, toluene or methylene chloride and added dropwise to a base suspension prepared in a three-necked flask under nitrogen atmosphere, which is used in an equimolar amount or in excess, such as e.g. sodium hydride , potassium hydroxide powder, potassium t-butoxide, dimethylaminopyridine or sodium amide, in a suitable solvent. The desired halide is then added, e.g. alkyl, aralkyl or heteroaralkyl, if necessary with the addition of a catalyst such as e.g. copper, and the mixture is reacted for a period of time, e.g. 30 minutes - 12 hours, and the temperature is kept at 0-120 ° C, preferably 30-80 ° C, especially 50-65 ° C. After completion of the reaction, the reaction mixture is added to water, the solution is extracted, e.g. diethyl ether, dichloromethane, chloroform, methyl t-butyl ether or tetrahydrofuran and the organic phase obtained in each case is dried

With anhydrous sodium sulfate. The organic phase is concentrated in vacuo, the residue is crystallized by trituration or the oily residue is purified by recrystallization, distillation or by column or flash chromatography on silica gel or alumina. The eluent used is e.g. a mixture of dichloromethane and diethyl ether in the ratio 8: 2 (v / v) or a mixture of dichloromethane and ethanol in the ratio 9: 1 (v / v).

Stage 2

The N-substituted indole obtained in step 1 above is dissolved under nitrogen in an aprotic or non-polar organic solvent such as e.g. diethyl ether, methyl t-butyl ether, tetrahydrofuran, dioxane, toluene, xylene, methylene chloride or chloroform and added to an equimolar to excess of 60% oxalyl chloride in an aprotic or non-polar solvent such as e.g. diethyl ether, methyl t-butyl ether, tetrahydrofuran, dioxane, toluene, xylene, methylene chloride, maintaining the temperature at -5 to 20 ° C. The reaction solution is then heated to 10-130 ° C, preferably 20-80 ° C and most preferably 30-50 ° C, for a period of 30 minutes to 5 hours, and then the solvent is evaporated off. The residue, in the form of "indolyl-3-glyoxyloyl chloride" thus obtained, is dissolved in an aprotic solvent such as e.g. tetrahydrofuran, dioxane, diethyl ether, toluene or alternatively in a dipolar aprotic solvent such as e.g. dimethylformamide, dimethylacetamide or dimethylsulfoxide is cooled to -15 to 10 ° C, preferably -5 to 0 ° C and treated in the presence of an acid binder, a solution of a primary or secondary amine in a diluent. Possible diluents include the solvents used above to dissolve indolyl-3-glyoxyloyl chloride. Acid binders used are triethylamine, pyridine, dimethylaminopyridine, anion exchanger, sodium carbonate, potassium carbonate, powdered potassium hydroxide, and an excess of the primary or secondary amine used in the reaction. The reaction takes place at a temperature of 0-120 ° C, preferably 20-80 ° C, most preferably 40-60 ° C. After a reaction time of 1-3 hours and standing at room temperature for 24 hours, the hydrochloride of the acid-binding agent is filtered off, the filtrate is concentrated in vacuo and the residue is recrystallized from an organic solvent or purified by column chromatography on silica gel or alumina. The eluent used is e.g. a mixture of dichloromethane and ethanol (95: 5, v / v).

Stage 3

The N-nitrobenzyl substituted "indologlyoxylamide" obtained by the above method (step 2) is dissolved in a protic solvent such as, for example, methanol, ethanol, propanol, isopropanol, or butanol, or in a non-polar solvent such as, for example, tetrahydrofuran, dioxane or glycol dimethyl ether, or in a dipolar aprotic solvent such as e.g. dimethylsulfoxide, dimethylformamide, dimethylacetamide or N-methylpyrrolidone, and a hydrogenation catalyst such as, for example, Raney Nickel, palladium on carbon or platinum, is added to the solution under nitrogen atmosphere and with stirring. Hydrogen is introduced into the slurry with moderate agitation at a gas pressure of 1-15 bar, preferably 2-10 bar, especially 4-6 bar, and the temperature is raised to about 20-80 ° C, preferably to 30-60 ° C, and especially up to 45-55 ° C. If necessary, after about 1 hour, more catalyst is added and the hydrogenation continued. The hydrogenation is complete after a reaction time of 4-10 hours. The catalyst is filtered off under nitrogen atmosphere, the solution is concentrated to dryness in vacuo and the colorless-yellowish residue is dried in vacuo at 40 ° C.

Examples

Following the general procedure of Steps 1-3 on which Scheme 1 is based, the following compounds were synthesized, shown below in tabulated form giving details of chemical names.

P ricycles 1

N- (Pyridin-4-yl) [1- (4-aminobenzyl) indol] -3-yl] glyoxyl] amide (D-68838)

Level 1

1- (4-Nitrobenzyl) indole

To a mixture of 5.28 g of sodium hydride (0.22 mol, mineral oil suspension) in 200 ml of dimethylsulfoxide, a solution of 23.4 g (0.2 mol) of indole in 100 ml of dimethylsulfoxide was added. The mixture was heated at 65 ° C for 1 hour, allowed to cool, and 37.7 g (0.22 mol) of 4-nitrobenzyl chloride was added dropwise. The solution was heated to 60 ° C, kept at room temperature for 14 hours, then poured into 700 ml of water with stirring. The mixture was extracted portion wise with a total of 300 ml of methylene chloride, the organic phase was dried with anhydrous

Sodium sulfate, filtered and the filtrate concentrated in vacuo. The residue is purified on a silica gel column (silica gel 60, Merck AG, Darmstadt; eluent-methylene chloride / ethanol 9: 1, v / v).

Yield: 43.9 g (87% of theory) MS: m / e 253 (M + H)

Stage 2

N- (Pyridin-4-yl) - [1- (4-nitrobenzyl) indol-3-yl] glyoxylamide (D-68836)

To a solution of 4.50 ml of oxalyl chloride in 50 ml of ether, a solution of 10.09 g (0.04 mol) of 1- (4-nitrobenzyl) indole 50 ml of ether was added dropwise at 0 ° C under nitrogen atmosphere. The mixture was refluxed for 2 hours, then the solvent was evaporated. 100 ml of tetrahydrofuran was added to the residue, the mixture was cooled to -5 ° C, and a solution of 9.21 g (0.099 mol) of 4-aminopyridine in 400 ml of tetrahydrofuran was added dropwise. The mixture was refluxed for 3 hours then allowed to stand overnight at room temperature. 4-Aminopyridine hydrochloride was filtered off with a suction pump and washed with tetrahydrofuran, the filtrate was concentrated in vacuo and the residue was recrystallized from ethyl acetate.

Yield: 13.5 g (84% of theory) mS: m / e 401 (M + H)

Stage 3

N- (Pyridin-4-yl) - [1- (4-aminobenzyl) indol-3-yl] glyoxylamide (D-68838)

To a mixture of 200 mg of Raney nickel in 50 ml of dioxane, a suspension of 320 mg (0.8 mmol) of N- (pyridin-4-yl) - [1- (4-nitrobenzyl) indol-3-yl] glyoxylamide in a solvent was added as a mixture of 150 ml of dioxane and 20 ml of isopropanol. Hydrogen gas was introduced into the shaking suspension at a gas pressure of 5 bar, maintaining the temperature at 30-35 ° C. After about 3 hours, another 400 mg of Raney Nickel was added and the hydrogenation was continued at 35 ° C and 5 bar for an additional 8 hours with vigorous shaking. The catalyst was filtered off under nitrogen atmosphere, the filtrate was concentrated to dryness in vacuo and the residue was dried in vacuo at 40 ° C.

Yield: 273 mg (92% of theory) MS: m / e 371 (M + H)

In addition, compounds of general formula 1 can also be synthesized as shown in scheme 2:

Scheme 2

<img file="PL195014B1_D0004.tif" />

PL 195 014 B1

N- (Pyridin-4-yl) - [1- (4-aminobenzyl) indol-3-yl] glyoxylamide

Level 1

N- (Pyridin-4-yl) - (indol-3-yl) glyoxylamide

A solution of 10 g (85.3 mmol) of indole in 100 ml of ether was added dropwise at 0 ° C to a solution of 9 ml of oxalyl chloride with 100 ml of anhydrous ether. The mixture was heated to reflux for 3 hours. Then a solution of 12 g (127.9 mmol) of 4-aminopyridine in 500 ml of tetrahydrofuran was added dropwise at -5 ° C, the reaction mixture was refluxed with stirring for 3 hours and allowed to stand overnight at room temperature. The mixture was filtered, the precipitate was treated with water, and the dried compound was purified on a silica gel column (silica gel 60, Merck AG, Darmstadt) using methylene chloride / ethanol (10: 1, v / v) as eluent.

Yield: 9.8 g (43.3% of theory) MS: m / e 266 (M + H)

Stage 2

N- (Pyridin-4-yl) - [1- (4-nitrobenzyl) indol-3-yl] glyoxylamide (D-68836)

N- (Pyridin-4-yl) - (indol-3-yl) glyoxylamide obtained in step 1 (scheme 2) was reacted with 4-nitrobenzyl chloride according to the "benzylation procedure" described for the synthesis of the compound according to scheme 1 and the resulting compound, N- (pyridin-4-yl) - [1- (4-nitrobenzyl) indol-3-yl] glyoxylamide.

Yield: 64% of theoretical amount MS: m / e 401 (M + H)

N- (Pyridin-4-yl) - [1- (4-aminobenzyl) indol-3-yl] glyoxylamide (D-68838)

N- (Pyridin-4-yl) - [1- (4-nitrobenzyl) indol-3-yl] -glyoxylamide obtained in step 2 (scheme 2) was catalytically hydrogenated according to the "hydrogenation procedure" described for the synthesis of the compound of scheme 1 and the obtained compound, N- (pyridin-4-yl) - [1- (4-aminobenzyl) -indol-3-yl] glyoxylamide, was isolated.

Yield: 94% of theoretical amount MS: m / e 371 (M + H)

General procedure for the preparation of compounds of general formula 1 according to scheme 2

Level 1

The indole derivative, which may be unsubstituted or mono-substituted or multisubstituted at C-2 or on the phenyl ring, dissolved in a solvent, e.g. as given above for oxalyl chloride, is added dropwise at a temperature of -5 to + 5 ° C to the prepared in a nitrogen atmosphere of a solution, at a concentration ranging from equimolar to 60% excess, of oxalyl chloride in an aprotic or non-polar solvent such as e.g. diethyl ether, methyl t-butyl ether, tetrahydrofuran, dioxane or optionally in dichloromethane. The reaction solution is then heated for 1-5 hours at 10-120 ° C, preferably 20-80 ° C and especially 30-60 ° C, and the solvent is evaporated off. The residue (indol-3-yl) glyoxyloyl chloride is dissolved or suspended in an aprotic solvent such as e.g. tetrahydrofuran, dioxane, diethyl ether, toluene or optionally in a dipolar aprotic solvent such as e.g. dimethylformamide, dimethylacetamide or dimethylsulfoxide are cooled to -10 to + 10 ° C, preferably -5 to 0 ° C and treated with the presence of an acid binder with a solution of a primary or secondary amine in a diluent. Possible diluents include the solvents used above to dissolve "indolyl-3-glyoxyloyl chloride". Acid binders used are triethylamine, pyridine, dimethylaminopyridine, anion exchanger, sodium carbonate, potassium carbonate, powdered potassium hydroxide, and an excess of the primary or secondary amine used in the reaction. The reaction takes place at a temperature of 0-120 ° C, preferably 20-80 ° C, most preferably 40-60 ° C. After a reaction time of 1-4 hours and standing at room temperature for 24 hours, the mixture is filtered, the precipitate is taken up in water, filtered off with a suction pump and dried in a vacuum. The desired compound is purified by recrystallization from an organic solvent or by column chromatography on silica gel or alumina. The eluent used is e.g. a mixture of dichloromethane and ethanol (10: 1, v / v).

Step 2 The "indol-3-ylglyoxylamide" obtained in step 1 above is dissolved in a protic, dipolar aprotic or nonpolar organic solvent such as, for example, isopropanol, tetrahydrofuran, dimethylsulfoxide, dimethylformamide, dimethylacetamide, N -oxmethylpyrrolidone, di-tetra or methylene chloride and added dropwise to a suspension of the base prepared in a three-necked flask under nitrogen atmosphere, which is used in an equimolar amount or in excess, such as e.g. sodium hydride, potassium hydroxide powder, potassium t-butoxide, dimethylaminopyridine

Or sodium amide, in a suitable solvent. The desired halide, e.g., alkyl, aralkyl or heteroaralkyl, is then added, undiluted or in a diluent which is also used e.g. to dissolve "indol-3-ylglyoxylamide", with the addition of a catalyst, such as e.g. copper, if necessary, and the mixture is reacted for a period of time, e.g. for 30 minutes - 12 hours, and the temperature is kept in the range of 0-120 ° C, preferably 30-80 ° C, especially 50-70 ° C. After completion of the reaction, the reaction mixture is added to water, the solution is extracted, for example with diethyl ether, dichloromethane, chloroform, methyl t-butyl ether, tetrahydrofuran or n-butanol, and the organic phase obtained in each case is dried with anhydrous sodium sulfate.

The organic phase is concentrated in vacuo, the residue is crystallized by trituration or the oily residue is purified by distillation or by column or flash chromatography on silica gel or alumina. The eluent used is, for example, a mixture of methylene chloride and diethyl ether in the ratio of 8: 2 (v / v) or a mixture of methylene chloride and ethanol in the ratio of 9: 1 (v / v).

Stage 3

The N-nitrobenzyl substituted "indologlyoxylamide" obtained by the above method (step 2) is dissolved in a protic solvent such as, for example, methanol, ethanol, propanol, isopropanol, or butanol, or in a non-polar solvent such as, for example, tetrahydrofuran, dioxane or glycol dimethyl ether, or in a dipolar aprotic solvent such as e.g. dimethylsulfoxide, dimethylformamide, dimethylacetamide or N-methylpyrrolidone, and a hydrogenation catalyst such as, for example, Raney Nickel, palladium on carbon or platinum is added to the solution under nitrogen atmosphere and with stirring. Hydrogen is introduced into the slurry with moderate agitation at a gas pressure of 1-15 bar, preferably 2-10 bar, especially 4-6 bar, and the temperature is raised to about 20-80 ° C, preferably to 30-60 ° C, and especially up to 45-55 ° C. If necessary, after about 1 hour, a further aliquot of catalyst is added and the hydrogenation continued. The hydrogenation is complete after a reaction time of 4-6 hours. The catalyst is filtered off under nitrogen atmosphere, the solution is concentrated to dryness in vacuo and the colorless-yellowish residue is dried in vacuo at 40 ° C.

Following this general procedure of Steps 1-3 on which Scheme 2 is based, compounds D-68836 and D-68838 were synthesized, which were already prepared according to the synthesis procedure outlined in Reaction Scheme 1.

The activity of the compounds of the invention in a tubulin polymerization test can be demonstrated. In particular, it was confirmed that D-68838 inhibits tubulin polymerization and therefore has a destabilizing effect on microchannels or mitotic spindles.