WO2004108723A1

WO2004108723A1 - 4,5-dihydro-imidazo[4,5,1-ii]quinolin-6-ones as parp inhibitors

Info

Publication number: WO2004108723A1
Application number: PCT/EP2004/051019
Authority: WO
Inventors: Johannes A. M. Christiaans; Steffen Weinbrenner; Thomas Klein; Dieter Flockerzi; Geert Jan Sterk; Wiro M. P. B. Menge; Paulus Johannes Gaurerius Brundel
Original assignee: Altana Pharma Ag
Priority date: 2003-06-04
Filing date: 2004-06-03
Publication date: 2004-12-16

Abstract

Compounds of the formula 1, in which R1 and R2 have the meanings indicated in the description, are novel active PARP inhibitors.

Description

4 , 5-DIHYDRO- IMIDAZθ ^" (4 , 5 , l - I I ) QUINO IN-6-ONES AS PARP INHIBITORS

Field of application of the invention

The invention relates to 4,5-Dihydro-imidazo[4,5,1-ij]quinolin-6-ones, which are used in the pharmaceutical industry for the production of pharmaceutical compositions.

Known technical background

In the International patent applications WOOO/42040, WO01/23386 and WO01/23390 3,4-Dihydro-1 ,2a,4- triaza-acenaphthylen-5-one derivatives are described as poly(ADP-ribosyl)transferase (PARP) inhibitors. In the European patent application EP 0405442 4,5-dihydro-imidazo[4,5,1-ij]quinolin-6-one derivatives are described with hypotensive, anti-oedematous and diuretic effects. In the European patent application EP 0646583 4,5-dihydro-imidazo[4,5,1-ij]quinolin-6-one derivatives are described as inhibitors for types 5-HT₃ and 5-HT₄ serotoninergic receptors. In the International patent application WO01/16136 8,9-Dihydro-7H- 2,7,9a-triaza-benzo[cd]azulen-6-one derivatives are disclosed as poly(ADP-ribosyl)transf erase (PARP) inhibitors; in this application 4,5-dihydro-imidazo[4,5,1-ij]quinolin-6-one derivatives are mentioned as possible intermediates. In the International patent application WO02/12239 4,5-dihydro-imidazo[4,5,1- ij]quinolin-6-one derivatives which are substituted by piperazinyl- or piperidinyl groups are disclosed as poly(ADP-ribosyl)transferase (PARP) inhibitors.

Description of the invention

It has now been found that the 4,5-Dihydro-imidazo[4,5,1-ij]quinolin-6-ones described in greater detail below have surprising and particularly advantageous properties.

The invention thus relates to compounds of formula 1

wherein

R1 is hydrogen or halogen,

R2 represents a group selected from

wherein R3 is hydrogen, 1-4C-alkyl, 1-4C-alkoxycarbonyl or 1-4C-alkylsulfonyl-1-4G-alkyl, and the salts, the N-oxides and the salts of the N-oxides of these compounds.

1-4C-Alkyl represents a straight -chain or branched alkyl radical having 1 to 4 carbon atoms. Examples which may be mentioned are the butyl, isobutyl, sec-butyl, tert -butyl, propyl, isopropyl and preferably the ethyl and methyl radicals.

1-4C-Alkoxy represents radicals which, in addition to the oxygen atom, contain a straight -chain or branched alkyl radical having 1 to 4 carbon atoms. Examples which may be mentioned are the butoxy, isobutoxy, sec-butoxy, tert-butoxy, propoxy, isopropoxy and preferably the ethoxy and methoxy radicals.

Halogen within the meaning of the invention is bromine, chlorine or fluorine.

1-4C-Alkoxycarbonyl represents a carbonyl group to which one of the abovementioned 1-4C-alkoxy radicals is bonded. Examples which may be mentioned are the methoxycarbonyl [GH₃0-C(0)-], the ethoxy- carbonyl [CH₃CH₂0-G(0)-] and the tert butoxycarbonyl [(CH₃)₃CO-C(0)-] radicals.

1-4C-Alkylsulfonyl is a sulfonyl group to which one of the abovementioned 1-4C-alkyl radicals is bonded. An example is the methanesulfonyl radical [CH₃S0₂-].

1-4C-Alkylsulfonyl-1-4C-alkyl represents a 1-4C-radical which is substituted by one of the above- mentioned 1-4G-alkylsulfonyl radicals. An example is the methylsulfonylethyl radical. Possible salts for compounds of the formula 1 - depending on substitution - are all acid addition salts or all salts with bases. Particular mention may be made of the pharmacologically tolerable salts of the inorganic and organic acids and bases customarily used in pharmacy. Those suitable are, on the one hand, water-soluble and water-insoluble acid addition salts with acids such as, for example, hydrochloric acid, hydrobromic acid, phosphoric acid, nitric acid, sulfuric acid, trifluoroacetic acid, acetic acid, citric acid, D-gluconic acid, benzoic acid, 2-(4-hydroxybenzoyl)benzoic acid, butyric acid, sulfosalicylic acid, maleic acid, lauric acid, malic acid, fumaric acid, succinic acid, oxalic acid, tartaric acid, embonic acid, stearic acid, toluenesulfonic acid, methanesulfonic acid or 3-hydroxy-2-naphthoic acid, it being possible to employ the acids in salt preparation - depending on whether a mono- or polybasic acid is concerned and depending on which salt is desired - in an equimolar quantitative ratio or one differing therefrom.

On the other hand, salts with bases are also suitable. Examples of salts with bases which may be mentioned are alkali metal (lithium, sodium, potassium) or calcium, aluminium, magnesium, titanium, ammonium, meglumine or guanidinium salts, where here too the bases are employed in salt preparation in an equimolar quantitative ratio or one differing therefrom.

Pharmacologically intolerable salts which can initially be obtained, for example, as process products in the preparation of the compounds according to the invention on an industrial scale are converted into pharmacologically tolerable salts by processes known to the person skilled in the art.

It is known to the person skilled in the art that the compounds according to the invention and their salts, when they are isolated, for example, in crystalline form, can contain various amounts of solvents. The invention therefore also comprises all solvates and in particular all hydrates of the compounds of the formula 1 , and also all solvates and in particular all hydrates of the salts of the compounds of the formula 1.

Compounds of formula 1 to be emphasized are those in which

R1 is hydrogen or fluorine,

R2 represents a group selected from

wherein R3 is hydrogen, butyl, tert.-butoxycarbonyl or methylsulfonylethyl, and the salts, the N-oxides and the salts of the N-oxides of these compounds.

Preferred compounds of formula 1 are selected from

2-(4-Thiomorpholin-4-yl-phenyl)-4,5-dihydro-imidazo[4,5,1-//]quinolin-6-one;

2-(4-Morpholin-4-yl-phenyl)-4,5-dihydro-imidazo[4,5,1- /]quinolin-6-one;

8-Fluoro-2-(4-morpholin-4-yl-phenyl)-4,5-dihydro-imidazo[4,5,1- /]quinolin-6-one;

8-Fluoro-2-(4-thiomorpholin-4-yl-phenyl)-4,5-dihydro-imidazo[4,5,1-/ ]quinolin-6-one;

2-[4-(1-Oxo-1λ⁴-thiomorpholin-4-yl)-phenyl]-4,5-dihydro-imidazo[4,5,1-//]quinolin-6-one;

2-[4-(1 ,1-Dioxo-1λ⁶-thiomorpholin-4-yl)-phenyl]-4,5-dihydro-imidazo[4,5,1- /]quinolin-6-one;

2-[4-(1,1-Dioxo-1λ⁶-thiomorpholin-4-yl)-phenyl]-8-fluoro-4,5-dihydro-imidazo[4,5,1-/)]quinolin-6-one;

4-[4-(6-Oxo-5,6-dihydro-4/-/-imidazo[4,5,1-//]quinolin-2-yl)-phenyl]-piperazine-1-carboxylic acid terf-butyl ester;

4-[4-(8-Fluoro-6-oxo-5,6-dihydro-4H-imidazo[4,5,1- /]quinolin-2-yl)-phenyl]-piperazine-1-carboxylic acid tert- butyl ester;

2-(4-Piperazin-1-yl-phenyl)-4,5-dihydro-imidazo[4,5,1-//]quinolin-6-one;

8-Fluoro-2-(4-piperazin-1-yl-phenyl)-4,5-dihydro-imidazo[4,5,1-//Jquinolin-6-one;

2-{4-[4-(2-Methanesulfonyl-ethyl)-piperazin-1-yl]-phenyl}-4,5-dihydro-imidazo[4,5,1-;)]quinolin-6-one;

2-[4-(4-Butyl-piperazin-1-yl)-phenyl]-4,5-dihydro-imidazo[4,5,1-/y]quinolin-6-one; and the salts, the N-oxides and the salts of the N-oxides of these compounds.

The preparation of compounds of formula 1 in which R1 and R2 have the meanings indicated above and their salts can be carried out, for example, by the processes described in EP0405442, EP0638570, WO01/16136 or by the processes described below (Reaction schemes 1 and 2) in greater detail.

Reaction scheme 1 shows the preparation of compounds of formula 1 , wherein R1 and R2 have the meanings mentioned above, starting from 2-nitroaniline, respectively 4-fluoro-2-nitroaniline.

a) Preparation of compounds of formula 1, wherein R1 has the meaning hydrogen and R2 has the meanings indicated above:

In a first step 2-nitroaniline is reacted with acrylonitrile to yield 3-(2-nitrophenylamino)propionitrile (compound A4). The propionitrile is then saponified to the corresponding propionic acid (starting compound A3). Cyclocondensation of starting compound A3 results in 2,3-Dihydro-8-nitro-1H-quinolin-4-one (starting compound A2). Selective reduction of the 8-nitro-group yields 2,3-Dihydro-8-amino-1 H-quinolin-4-one (starting compound A1 ). The compounds of formula 1 are obtained in the final step by reacting starting compound A1 with aldehydes of formula 2, in which R2 has the above indicated meanings.

Aldehydes of formula 2, in which R2 has the meanings indicated above are known or can be prepared according to methods known to the per-son skilled in the art.

b) Preparation of compounds of formula 1 , wherein R1 has the meaning fluorine and R2 has the meanings indicated above:

The fluorine substituted compounds of formula 1 are prepared analogously to the compounds of formula 1, wherein R1 has the meaning hydrogen.

In a first step 4-fluoro-2-nitroaniline is reacted with acrylonitrile to yield 3-(4-fluoro-2-nitrophenylamino)- propionitrile (compound A8). The propionitrile is then saponified to the corresponding propionic acid (starting compound A7). Cyclocondensation of starting compound A7 results in 2,3-Dihydro-6-fluoro-8-nitro-1H- quinolin-4-one (starting compound A6). Selective reduction of the 8-nitro-group yields 2,3-Dihydro-8- amino-1H-quinolin-4-one (starting compound A5).

The compounds of formula 1 are obtained in the final step by reacting starting compound A5 with aldehydes of formula 2, in which R2 has the above indicated meanings.

Detailed reaction conditions are described in the section "starting compounds" and "final products". An alternative preparation method for the starting compounds can also be found in WO01/16136.

Reaction scheme 1 :

^"CN ^^■CN

^R- (²) ^ -^{R2 (}2⁾

An further alternative preparation method for compounds of formula 1 , wherein R1 and R2 have the above mentioned meanings is shown in reaction scheme 2. Compounds of formula 1 can also be prepared reacting 2-chloro-4,5-dihydro-imidazo[4,5,1-ij]quinoline-6- one respectively 2-chloro-8-fluoro-4,5-dihydro-imidazo[4,5,1-ij]quinoline-6-one in a Suzuki coupling reaction with phenylboronic acid derivatives (for example, 4-[N-(tert-butyloxycarbonyl)piperazinyl]phenylboronic acid).

^'Additionally, compounds of formula 1 can be converted in further compounds of formula 1. For example, compounds of formula 1 , wherein R1 has the above-mentioned meanings and R2 is a piperazino ring can be alkylated with compounds of formula R3-X, wherein R3 is for example 1-4C-alkyl and X is a suitable leaving group, for example a halogen atom, preferably a iodine atom. Alternatively, the compounds of formula 1 , wherein R1 has the above-mentioned meanings and R2 is a piperazino ring can be used for all kinds of Michael addition reactions with Michael acceptors, for example methyl vinyl sulfone.

Compounds of formula 1, wherein R1 has the above-mentioned meanings and R2 is a thiomorpholino ring can be converted in further compounds of formula 1 to give 1-oxo-1λ⁴-thiomorpholin-4-yl or 1 ,1-dioxo-1λ^B- thiomorpholin-4-yl derivatives by an oxidation reaction. A suitable oxidizing agent is for example 3- chloroperoxybenzoic acid.

Reaction scheme 2:

Michael

In addition, the compounds of formula 1 can be converted, if desired, into their N-oxides, for example with the aid of hydrogen peroxide in methanol or with the aid of m-chloroperoxybenzoic acid in dichloro- methane. The person skilled in the art is familiar on the basis of his/her expert knowledge with the reaction conditions which are specifically necessary for carrying out the N-oxidation. It is known to the person skilled in the art that in those compounds of formula 1, in which R2 represents a thiomorpholino- or 1-oxo- thiomorpholino-ring, the formation of a corresponding N-oxide will not be possible, because the oxidation of the thiomorpholino-ring respectively the 1-oxo-thiomorpholino-ring to the 1,1-dioxo-thiomorpholinio-riπg will take place under milder oxidation conditions than the formation of the N-oxide.

It is also known to the person skilled in the art that in the case of a number of reactive centers on a starting or intermediate compound it may be necessary to block one or more reactive centers temporarily by protective groups in order to allow a reaction to proceed specifically at the desired reaction center. A detailed description of the use of a large number of proven protective groups is found, for example, in T.W. Greene, Protective Groups in Organic Synthesis, John Wiley & Sons, 1991 . The isolation and purification of the substances according to the invention is carried out in a manner known per se, e.g. by distilling off the solvent in vacuo and re crystallizing the resulting residue from a suitable solvent or subjecting it to one of the customary purification methods, such as, for example, column chromatography on suitable support material.

Salts are obtained by dissolving the free compound in a suitable solvent (e.g. a ketone, such as acetone, methyl ethyl ketone or methyl isobutyl ketone, an ether, such as diethyl ether, tetrahydrofuran or diox- ane, a chlorinated hydrocarbon, such as methylene chloride or chloroform, or a low molecular weight aliphatic alcohol such as ethanol or isopropanol) which contains the desired acid or base, or to which the desired acid or base is then added. The salts are obtained by filtering, reprecipitating, precipitating with a nonsolvent for the addition salt or by evaporating the solvent. Salts obtained can be converted by alkaliza- tioπ or by acidification into the free compounds, which in turn can be converted into salts. In this way, pharmacologically intolerable salts can be converted into pharmacologically tolerable salts.

The following examples serve to illustrate the invention further without restricting it. Likewise, further compounds of the formula 1 , whose preparation is not explicitly described, can be prepared in an analogous manner or in a manner familiar per se to the person skilled in the art using customary process techniques.

In the examples, h stands for hour(s) and RT for room temperature. The compounds mentioned in the examples and their salts are a preferred subject of the invention.

Examples

Final products

1. 2-(4-Thiomorpholin-4-yl-phenylV4,5-dihydro-imidazor4,5.1-/71quinolin-6-one

0.55 g (3.4 mmol) 8-amino-2,3-dihydro-1H-quinolin-4-one, 0.7 g (3.4 mmol) 4-thiomorpholin-4-yl-benz- aldehyde and 0.44 g (4 mmol) 1 ,4-benzoquinone are refluxed in 40 mL ethanol for 4 h. After cooling to RT the mixture is filtered. The filtrate is purified by flash chromatography (solvent system: ethyl acetate/petroleum ether 60-80°C/triethylamine, 3/1/0.1 v/v/v) to yield 340 mg of the title compound. M. p. 161- 162 °C

2. 2-(4-Morpholin-4-yl-phenvπ-4.5-dihvdro-imidazor4.5.1-//|quinolin-6-one

Prepared analogously to the method described for example 1. M. p. 211-212 °C

3. 8-Fluoro-2-(4-morpholin-4-yl-phenylV4.5-dihvdro-imidazor4.5.1-/ lquinolin-6-one

Prepared analogously to the method described for example 1. M. p. 238-240 °C

4. 8-Fluoro-2-(4-thionnorpholin-4-yl-phenylV4.5-dihvdro-imidazor4.5.1-//1guinolin-6-one

Prepared analogously to the method described for example 1. M. p. 187-188 °C

5. 2-r4-f1-Oxo-1 ⁴-thiomorpholin-4-yl phenyn-4.5-dihvdro-imidazor4.5.1-/7lquinolin-6-one and

6. 2-r4-f1.1-Dioxo-1λ⁶-thiomoφholin-4-ylVphenyn-4.5-dihydro-imidazof4.5.1-/ lquinolin-6-one

0.24 g 2-(4-Thiomorpholin-4-yl-phenyl)-4,5-dihydro-imidazo[4,5,1-/ ]quinolin-6-one are dissolved in dichloromethane and cooled to 0°C. 0.28 g 3-Chloroperoxybenzoic acid (75%) is added and stirred for 3 h. Sodium sulfite solution is added and the mixture is extracted with dichloromethane. The dichloromethane layer is dried with MgS0 , filtered and evaporated. Flash chromatography (ethyl acetate/metha- nol/triethylamine, 4/1/0.2 v/v/v) affords the sulfoxide 2-[4-(1-Oxo-1λ⁴-thiomorpholin-4-yl)-phenyl]-4,5-di- hydro-imidazo[4,5,1-i/]quinolin-6-one (Rf value sulfoxide = 0.76; solvent system: ethyl acetate/metha- nol/triethylamine, 4/1/0.2 v/v/v) and the sulfone 2-[4-(1 ,1-Dioxo-1λ^s-thiomorpholin-4-yl)-phenyl]-4,5-dihydro- imidazo[4,5,1-//]quinolin-6-one (Rf value sulfone = 0.43; solvent system: ethyl acetate/methanol/- triethylamine, 4/1/0.2 v/v/v). The sulfoxide is crystallized from ethyl acetate to yield 70 mg; M. p. 275-276^0

The sulfone is stirred in diethyl ether and filtered to yield 30 mg; M. p. 209-210 °C

7. 2-f4-H .1-Dioxo-1λ⁶-thiomorpholin-4-ylVphenyll-8-fluoro-4.5-dihydro-imidazor4,5.1- //lquinolin-6-one

Prepared analogously to the method described for example 6. M. p. 249-250 °C

8. 4-r4-(6-Oxo-5.6-dihydro-4Wmidazor4.5.1- ;1quinolin-2-yl -phenyl^'|-piperazine-1-carboxylic acid terf-butyl ester

0.8 g (34.4 mmol) 2-chloro-4,5-dihydro-imidazo[4,5,1-/y]quinolin-6-one is dissolved in 1 ,2-dimethoxy- ethane. 0.22 g tetrakis(triphenylphosphine)palladium and 2.3 g 4-[N-(ferf-butyloxycarbonyl)piperazinyl]- phenylboronic acid and 7.7 ml 2M sodium carbonate solution are added. The mixture is refluxed for 17 h. After cooling ethyl acetate and water are added. The ethyl acetate layer is dried with MgS0₄ and evaporated. The residue is purified by flash chromatography (solvent system: petroleum ether 60-80°C/ ethyl acetate/triethylamine, 3/2/0.1 v/v/v) to yield 1.1 g of the title compound. M. p. 192-193 °C

9. 4-r4-(8-Fluoro-6-oxo-5.6-dihvdro-4 - imidazor4.5.1-/ 1quinolin-2-ylVphenvn-piperazine-1- carboxylic acid ferf-butyl ester

0.64 g (3.5 mmol) 8-amino-6-fluoro-2,3-dihydro-1/-/-quinolin-4-one, 0.74 g (3.5 mmol) 4-(4-formyl-phen- yl)piperazine-1-carboxylic acid tert-butyl ester and 0.46 g (4.2 mmol) 1 ,4-benzoquinone are refluxed in 40 mL ethanol for 4 h. After cooling to RT the mixture is filtered and the solvent evaporated. The residue is purified by flash chromatography (solvent system: ethyl acetate/petroleum ether 60-80°/triethylamine, 1/1/0.1 v/v/v). The pure fractions are combined and crystallized from ethyl acetate/diethyl ether to yield 250 mg of the title compound. M. p. 218-219 °C

10. 2-(4-Piperazin-1-yl-phenylV4,5-dihvdro-imidazor4.5.1-/>1quinolin-6-one ris-trifluoroacetate salt

1 g 4-[4-(6-Oxo-5,6-dihydro-4H-imidazo[4,5,1- /]quinolin-2-yl)-phenyl]-piperazine-1 -carboxylic acid tert- butyl ester is dissolved in 1.5 mLtrifluoroacetic acid and stirred for 1 h. The solvent is evaporated. The residue is crystallized from ethyl acetate to yield 1.4 g of the title compound. M. p. 172-173 °C 11. 8-Fluoro-2-(4-piperazin-1-yl-phenyl)-4,5-dihvdro-imidazor4.5.1-/71quinolin-6-one tris- trifluoroacetate salt

190 mg 4-[4-(8-fluoro-6-oxo-5,6-dihydro-4H-imidazo[4,5,1-/)]quinolin-2-yl)-phenyl]-piperazine-1-carboxylic acid tert-butyl ester is dissolved in 3 mL trifluoroacetic acid and stirred for 1 h at RT. The solvent is evaporated. The residue is crystallized from ethyl acetate to yield 190 mg of the title compound. M. p. 270 °C decomposes.

12. 2-(4-r4-(2-Methanesulfonyl-ethylVpiperazin-1-yll-phenyll-4.5-dihydro-imidazor4.5,1- / lquinolin-6-one

0.6 g 2-(4-Piperazin-1-yl-phenyl)-4,5-dihydro-imidazo[4,5,1-/;]quinolin-6-one and 0.4 g triethylamine are dissolved in dichloromethane. 0.18 g methyl vinyl sulfone is added. The reaction mixture is stirred for 72 h at RT. The organic layer is washed with sodium bicarbonate solution, dried with MgS0₄, filtered and evaporated to dryness. The title compound is crystallized from an ethyl acetate / diethyl ether mixture to yield 330 mg. M. p. 217 °C (decomposes).

13. 2-r4-(4-Butyl-piperazin-1-yπ-phenyn-4,5-dihvdro-imidazor4.5.1-/7lquinolin-6-one

0.5 g 2-(4-Piperazin-1-yl-phenyl)-4,5-dihydro-imidazo[4,5,1-//]quinolin-6-one, 0.18 g 4-iodobutane, 0.45 g potassium carbonate are dissolved in N,N-dimethylformamide and stirred for 36 h at 60 °C. After cooling, water is added and the mixture is extracted with ethyl acetate. The combined ethyl acetate layers are dried with MgS0₄, filtered, and evaporated to dryness. The residue is purified by flash chromatography (solvent system: petroleum ether 60-80°/ ethyl acetate/triethylamine, 1/1/0.05 v/v/v). The pure fractions are combined, evaporated and stirred in diethyl ether. The solid is collected yielding in 110 mg of the title compound. M. p. 180-181 °C

Startinq compounds

A1. 2.3-Dihvdro-8-amino-1H-quinolin-4-one

8.6 g 2,3-Dihydro-8-nitro-1 H-quinolin-4-one (A2) is dissolved in 600 ml methanol and 0.85 g Pd/C (10%) is added under an atmosphere of nitrogen. The mixture is hydrogenated under atmospheric pressure for 16 h. The mixture is filtered over celite and evaporated to dryness. The residue is purified by flash chromatograpy to yield 5.95 g of the title compound.

¹H-NMR (200MHz, D₆-DMSO): δ= 2.45-2.52 (m,2H), 3.41 -3.49 (m,2H), 4.75 (s, 2H), 5.83 (s,1 H), 6.42 (t, 1 H), 6.67 (dd, 1H), 6.98 (dd,1 H).

Alternatively, the starting compound A1 can be prepared as described in WO01/16136.

A2. 2.3-Dihydro-8-nitro-1H-quinolin-4-one

A mixture of 21.0 g 3-(2-nitrophenylamino)-propionic acid (A3) and 42.5 g phosphorus pentoxide in 300 ml abs. toluene is heated at reflux for 2 h. The mixture is filtered and the residue extracted three times with 300 ml of boiling ethyl acetate. The filtrates and extracts are evaporated to dryness to give 10.9 g of the desired product.

¹H-NMR (200MHz, D₅-DMSO): δ= 2.70 (t, 2H), 3.62-3.75 (m, 2H), 6.74 (t, 1 H), 8.04 (dd, 1 H), 8.30 (dd, 1H), 8.61 (s, 1H).

A3. 3-(2-Nitrophenylamino)propionic acid

66.0 g 3-(2-nitrophenylamino)-propionitrile (A4) are suspended in 500 ml 10% KOH and stirred at 130°C for 1.5 h. The clear orange solution is cooled and brought to pH=3 with cone. HCI. After cooling the yellow precipitate is filtered off, washed with water and dried, yielding 63 g.

¹H-NMR (200MHz, D₆-DMSO): δ= 2.61 (t, 2H), 3.58 (q, 2H), 6.63-6.72 (m, 1 H), 7.09 (dd, 1 H), 7.49-7.60 (m, 1H), 8.08 (dd, 1 H), 8.19 (t, 1H).

A4. 3-(2-Nitrophenylamino)propionitrile

A solution of 104 g of 2-nitroaniline and 15 ml of Triton B in 500 ml abs ethanol is heated to 80°C and 140 ml acrylonitrile are addded over a period of 5 h. Stirring at 80°C is continued for 24 h. EtOH is removed in vacuo, the oily residue dissolved in 300 ml ethyl acetate, treated with charcoal and 400 ml petrolether are added. After cooling coarse brown crystals are filtered off, yielding 61 g of the desired product.

¹H-NMR (200MHz, D₆-DMSO): δ= 2.89 (t, 2H), 3.72 (q, 2H), 6.70-6.78 (m, 1 H), 7.18 (dd, 1 H), 7.49-7.50 (m, 1 H), 8.07 (dd, 1 H), 8,25 (t, 1 H).

A5. 8-Amino-6-fluoro-2.3-dihydro-1H-quinolin-4-one

4.6 g (21.9 mmol) 6-fluoro-8-nitro-2,3-dihydro-1 /-/-quinolin-4-one (A6) are dissolved in 120 mL ethanol and 19.8 g (87 mmol; 4 equivalents) tin(ll)chloride dihydrate is added. The mixtured is refluxed for 2 h. The ethanol is evaporated and the residue is dissolved in ethyl acetate. A 1 M NaOH solution is added until the solvent mixture is basic (pH = 10). The ethyl acetate layer is separated, dried with MgS0₄ and evaporated to yield 2.3 g (12.8 mmol) of the title compound, which is used immediately without further purification.

Mass spectrometry [M+H]⁺ = 181

H-NMR (DMSO)chemical shifts in ppm: δ= 2.52 (m,2H), 3.41-3.47 (m,2H), 5.24 (bs, 2H), 5.86 (bs, 1 H),

6.55 (dd, 1 H), 6.61 (dd,1 H).

A6. 6-fluoro-8-nitro-2,3-dihydro-1H-quinolin-4-one

Prepared as described in WO01/16136.

A7. 3-(4-fluoro-2-nitrophenylaminoVpropionic acid

Prepared as described in WO01/16136.

A8. 3-(4-Fluoro-2nitrophenylaminoVpropionitrile

1.56 g (10 mmol) 4-Fluoro-2-nitroaniline, 4 mL (60 mmol) acrylonitrile and 1.38 g (10 mmol) potassium carbonate are added to 15 mL Λ/,Λ/-dimethylformamide and stirred at 95 °C under nitrogen atmosphere for 3 h. The solvent is evaporated. The residue is dissolved in ethyl acetate and washed with water and brine. The ethyl acetate layer is dried with MgS0₄ and evaporated. The residue is stirred in petroleum ether 60- 80°C and filtered to yield 2 g of the title compound.

¹H-NMR (200MHz, CDCI₃): δ= 2.68 (t,2H), 3.60-3.70 (m,2H), 6.78 (dd, 1 H), 7.22-7.30 (m, 1H), 7.87 (dd, 1H), 8.00 (bs,1 H). A9. 2-chloro-4.5-dihydro-imidazor4.5.1-/^'flαuinolin-6-one

7.3 g 3-(2-Chloro-benzoimidazol-4-yl)-propionic acid (A12) are suspended in 20 ml thionylchloride and slowly heated to reflux. The acid goes into solution and after a few minutes the solution goes into a precipitate. After 20 in the excess thionylchloride is evaporated in vacuo, the acid chloride is dissolved in 1 ,2.dichloroethane and 12.2 g aluminiumchloride is added in portions. The mixture is refluxed overnight, poured on ice and made alkaline by adding 2 N sodium hydroxide solution. The solution is filtered over Celite and then extracted three times with dichloromethane. After drying the organic solvents are evaporated yielding a brown oil which solidified upon standing, yielding 3.0 g of the desired product.

H-NMR (200MHz, CDCI₃): δ= 3.05 (t, 2H), 4.45 (t, 2H), 7.25 (t, 1 H), 7.60 (d, 1H), 7.75 (d, 1H).

A10. 4-rN-(ferf-butyloxycarbonvπpiperazinyllphenylboronic acid

Prepared as described in WO02/069901.

A11. 4-(4-Formyl-phenviypiperazine-1-carboxylic acid tert butyl ester

Prepared analogously to the method described by Tanaka et al. (J.Med.Chem. 41 : 2390-2410, 1998) from 4-fluorobenzaldehyde and tert-butyl-1-piperazinecarboxylate. This compound is also described by_. Wata- nabe et al. in Chem.Pharm.Buli. 45: 1458-1469, 1997.

A12. 3-(2-Chloro-benzoimidazol-4-ylVpropionic acid

18 g 2-chloro-1 H-benzimidazole, 15.3 g 3-chloropropionic acid methyl ester and 60 g potassium carbonate are suspended in 500 ml acetone. The mixture is gently refluxed for 4 h. The mixture is filtered hot over a paper filter and evaporated to dryness. The excess of volatile ester is removed in vacuo. This yields 28.5 g of 3-(2-chloro-benzoimidazol-1-yl)-propionic acid methyl ester as a yellow oil. This crude product is dissolved in 100 ml acetone and hydrolysed by stirring at RT with 100 ml 2.5 N potassium hydroxide solution. After stirring overnight the acetone is partly removed, water is added and the solution is acidified until pH=6. The precipitate is filtered off and air-dried to yield 21.8 g of the title compound.

H-NMR (200MHz, D₆-DMSO): δ= 2.75 (t, 2H), 4.45 (t, 2H), 7.15-7.35 (m, 2H), 7.50-7.65 (m,2H). Commercial applicability

The compounds according to the invention have valuable pharmacological properties which make them commercially utilizable. They are inhibitors of the Poly(ADP-ribose)polymerase enzymes, in particular of the PARP-1 isoenzyme. Poly(ADP-ribose) polymerases (PARP, also called PARS, NAD⁺-ADP-ribosyl- trans-ferase, pADPRT(EC 2.4.2.30)) are enzymes located in the nuclei of cells of various organs, including muscle, heart, brain and pancreatic cells. PARPs poly-ADP-ribosylate various nuclear proteins and also show auto-poly-ADP-ribosylating properties. PARPs play a physiological role in the maintainance of genomic integrity and stability. While till the late nineties only one PARP-enzyme was known, it is now clear that a whole family of related enzymes exists. Up to now the PARP-family consists of 7 isoenzymes showing high to moderate sequence homologies. High overall homology is found between the isoenzymes PARP-1 to PARP-3. The other isoforms display relevant homologies only at the catalytic site while the other domains of the proteins are completely different. The exact functions of most isoenzymes are not yet known, but it is clear that PARP-1 is physiologically involved in DNA-repair (ikai et al., J. His- tochem. Cytochem. 11: 1261-1264, 1983) and transcriptional regulation. PARP-1 is highly expressed in the nuclei of cells and is a member of the base excision repair complex (BER-complex). Once activated by damaged DNA fragments, PARP-1 catalyzes the attachment of up to 100 ADP-ribose units to a variety of nuclear proteins which are involved in DNA repair, including histones, topoisomerases, DNA- polymerases, DNA-ligases and PARP-1 itself. NAD is used as a source of ADP-ribose. Poly-ADP- ribosylation is thought to stabilize the region of the single strand break and to allow the recruitment of other DNA-repair enzymes. Consumed NAD is regenerated by the use of 4 ATP -molecules for every molecule of NAD. After intense auto-ADR-ribosylation PARP-1 becomes negatively charged and dissociates from the DNA.

A high number of DNA strand breaks caused by inflammatory mediators, ischemia/ reperfusion or other stimuli leads to a massive overactivation of PARP-1. It has been shown that overactivation of PARP's especially PARP-1 leads to an immediate consumption of cellular NAD. Thus, intracellular NAD, the substrate of PARP, and ATP are depleted by massive PARP activation and this energy depletion is thought to be one stimulus leading to cellular damage and cell death.

It is well known that temporary oxygen deprivation as found in situations of ischemia and reperfusion leads to the generation of reactive oxygen species which alone or in combination with nitric oxide lead to massive DNA strand breaks. In an effort to repair these strand breaks PARP-1 is overactivated, resulting in cellular NAD and ATP depletion, cell death and organ damage. In isolated organ systems such as heart or skeletal muscle PARP inhibition diminishes ischemia/reperfusion induced tissue damage (Thie- mβrman etal. PN AS 94,: 679-683, 1997) and contractile dysfunction (Docherty et al. Br. J. Pharmacol. 127,: 1518-1524, 1999). Protection from PARP mediated cell death has been shown in PARP-1 knockout mice in various in-vivo models of cerebral and myocardial ischemia/reperfusion injury. A massive re- duction of the necrotic area in the CNS was reported in PARP-1 -knock out mice after transient occlusion of the middle cerebral artery. Protection from myocardial ischemia/reperfusion damage was also seen in PARP-1 knock out mice after transient coronary occlusion. In models of cardiac ischemia and myocardial infarction PARP inhibitors reduce infarct size. It has been shown in myocytes that PARP inhibition inhibits cellular oxydative damage (Bowes etal. Br. J. Pharmacol. 124: 1760-1766, 1998).

Similarly, in models of retinal ischemia/reperfusion PARP inhibition has been shown to reduce cellular and organ damage. Confirming results are available from small molecule inhibitors of PARPs in models of transient cerebral ischemia and transient retinal ischemia (Lam, Res. Com. Mol. Pathol. Pharmacol. 95, 241-252, 1997).

Similarly, acute or chronic inflammation in general is characterised among others by massive generation of reactive oxygen species and nitric oxide. As in the case of ischemia/reperfusion these reactive species lead to DNA strand breaks, PARP-1 overactivation and cell death. It has been shown that PARP inhibition by small molecule inhibitors or genetic knock out reduces edema formation after zymosan or carra- geenan, inhibits cellular damage in pancreatic islet cells after streptozotocin, inhibits experimental arthritis and reduces intestinal damage in models of intestinal inflammation. Evidence exists that PARP inhibitors are useful for treating inflammatory bowel disorders. (Salzman et al., Japanese J. Pharm., 75, Supp. 1:15, 1997). In rodent in vivo models experimentally induced colitis was reduced by administration of PARP inhibitors.

Evidence also exists that PARP inhibitors are useful for treating arthritis. (Szabo et al., Japanese J. Pharm., 75, Supp. 1:102, 1997). Beside an inhibition of cellular damage due to the above mentioned mechanisms it has been demonstrated that PARP inhibition reduces the expression of proinflammatory adhesion molecules such as ICAM-1 and P-selectin.

It has also been reported that PARP activation plays a key role in glutamate-, NMDA-, NO-, reactive oxygen species- and glucose deprivation induced neurotoxicity. The use of PARP inhibitors was reported to prevent neurotoxicity in cortical or cerebellar granule cell cultures and in hippocampal slices (Wallis et al., NeuroReport, 5:3, 245-48. 1993; Cos! etal, J. Neurosci. Res 39: 38-46, 1994; Eliasson etal. Nature Med. 3: 1089-1095, 1997); Inhibition of neurotoxicity by various compounds was found to correspond to their PARP-1 inhibitory potency (Zhang etal., Science, 263:687-89, 1994); Excessive activation of glutamate receptors has been implicated in various neurological diseases. NO together with reactive oxygen species has been shown to be causally involved in in-vivo models for various neurodegenerative diseases of the CNS. During ischemia/reperfusion injury various neurotoxic species including glutamate, NO, reactive oxygen species and others are released leading to massive organ damage. Other pathophysiological stimuli resulting in PARP activation and concomittant cell damage are 1-methyl-4-phenyl-1 ,2,3,6- tetrahydropyridine (MPTP), leading to experimental parkinsonism, immune complexes mediating experimental encephalomyelitis and traumatic head injury.

There are also data showing that PARP inhibitors reduce the severity of septic or hemorrhagic shock in animal models. Survival of mice after a lethal dose of LPS was increased by PARP inhibitors (Szabo et al. Int. J. Oncology 10, 1093-1101, 1997). In addition organ dysfunction (shown for lung, liver, intestine) after zymosan in experimental models of shock is reduced by PARP inhibitors (Szabo et al. J.Exp. Med. 186, 1041-1049, 1997).

It has also been shown that PARP-1 inhibition protects pancreatic islet cells from NO or reactive oxygene species induced damage (Uchigata et al. J. Biol. Chem. 2576084- 6088,1982). In more complex models of streptozotocin induced diabetes, PARP-1 inhibition reduced cellular damage and increased insulin production (Uchigata et al. Diabetes 32, 316-318, 1983)

PARP inhibitors have been reported to be effective in radiosensitizing hypoxic tumor cells and in preventing tumor cells from recovering from potentially lethal damage of DNA after radiation therapy, presumably by their ability to prevent DNA repair (Griffin et al. J. Med. Chem. 41, 5247-5256, 1998).

On account of their PARP - in particular their PARP-1 - inhibiting properties, the compounds according to the invention can be employed in human and veterinary medicine and therapeutics, where they can be used for the treatment and prophylaxis of the following diseases: vascular stroke (cerebral stroke), myocardial infarction and other cardiovascular disorders (artherosclerosis), diabetes, head trauma, sepsis and septic shock; hemorrhagic shock, tissue damage resulting from PARP-1 mediated necrosis or apoptosis; any kind of reperfusion injury; especially neuronal (CNS), myocardial, retinal or other tissue damage resulting from ischemia and reperfusion; ischemia/reperfusion injury during organ transplantation surgery, surgery with transient interruption of blood flow to organs or body areas, and surgery when heart- lung/heart-circulation machines are used; renal failure due to ischemia or glomerulonephritis, retinal ischemia; neurological disorders and neurodegenerative diseases caused by free radical generation or other PARP-1 activating stimuli; pancreatic disorders; acute and chronic inflammatory diseases (chronic inflammatory disease of the CNS (Alzheimer, multiple sklerosis, Parkinson's disease), chronic inflammatory diseases of the gastrointestinal tract (Morbus Crohn, colitis ulcerosa), chronic inflammatory diseases of the lungs (acute lung injury, ARDS), chronic inflammatory diseases of the joints (rheumatoid arthritis, osteoarthritis), acute inflammatory diseases of various organs; traumata of various organs; viral infections which rely on PARP-activity for successful DNA integration; infections by human immune deficiency and other viruses (AIDS); degenerative diseases of skeletal muscle involving replicative senescence, immune senescence, muscular dystrophy, chronic and acute pain (neuropathic pain), and skin aging. ln addition to this, conditions including epilepsy, stroke, Alzheimer's disease, Parkinson's disease, Amyotrophic Lateral Sclerosis (ALS), Huntington's disease, schizophrenia, chronic pain, ischemia and neuronal loss following hypoxia, hypoglycemia, ischemia, trauma, and nervous insult can be expected to be mitigated by PARP-1 inhibition. Recent studies have also advanced a glutamatergic basis for compulsive disorders, particularly drug dependence.

Furthermore PARP -inhibitors can be used to extend the lifespan and proliferative capacity of cells; to alter gene expression of senescent cells and to enhance the efficacy of chemo- or radiotherapy in cancers. PARP-inhibitors can also be used to potentiate cellular necrosis and/or apoptosis by chemotherapeutic compounds of various classes.

The invention further relates to a method for the treatment of mammals, including humans, which are suffering from one of the abovementioned illnesses. The method is characterized in that a therapeutically active and pharmacologically effective and tolerable amount of one or more of the compounds according to the invention is administered to the ill mammal.

The invention further relates to the compounds according to the invention for use in the treatment and/or prophylaxis of illnesses, especially the illnesses mentioned.

The invention also relates to the use of the compounds according to the invention for the production of pharmaceutical compositions which are employed for the treatment and/or prophylaxis of the illnesses mentioned.

The invention furthermore relates to pharmaceutical compositions for the treatment and/or prophylaxis of the illnesses mentioned, which contain one or more of the compounds according to the invention.

The pharmaceutical compositions are prepared by processes which are known per se and familiar to the person skilled in the art. As pharmaceutical compositions, the compounds according to the invention (= active compounds) are either employed as such, or preferably in combination with suitable pharmaceutical auxiliaries and/or excipients, e.g. in the form of tablets, coated tablets, capsules, caplets, suppositories, patches (e.g. as TTS), emulsions, suspensions, gels or solutions, the active compound content advantageously being between 0.1 and 95% and where, by the appropriate choice of the auxiliaries and/or excipients, a pharmaceutical administration form (e.g. a delayed release form or an enteric form) exactly suited to the active compound and/or to the desired onset of action can be achieved.

The person skilled in the art is familiar with auxiliaries or excipients which are suitable for the desired pharmaceutical formulations on account of his/her expert knowledge. In addition to solvents, gel formers, ointment bases and other active compound excipients, for example antioxidants, dispersants, emulsifiers, preservatives, solubilizers, colorants, complexing agents or permeation promoters, can be used.

The administration of the pharmaceutical compositions according to the invention may be performed in any of the generally accepted modes of administration available in the art. Illustrative examples of suitable modes of administration include intravenous, oral, nasal, parenteral, topical, transdermal and rectal delivery. Oral and intravenous delivery is preferred.

The pharmaceutical compositions according to the invention are prepared by processes known per se. Dosage of the active compounds takes place in the order of magnitude customary for PARP inhibitors. Thus topical application forms (such as, for example, ointments) contain the active compounds in a concentration of, for example, 0.1-99%. For oral administration, e.g., the dosage that may be employed is from about 0.1 to about 100 mg/kg body weight, with courses of treatment repeated at appropriate intervals.

Bioloαical investigations

The potency of the compounds according to the invention to inhibit PARP-1 activity is tested by measuring the auto-ADP-ribosylation reaction at the level of partially purified human PARP-1. Cellular PARP- activity was measured by quantification of nuclear poly-ADP-ribose polymer.

Measurement of enzymatic PARP-1 activity

100 ng of a crude cytosolic fraction of Sf9-cells expressing PARP-1 are incubated in a total volume of 200 μl in the presence of 100 mM Tris/HCI pH 7.4, 1 μM NAD, 1.5 μg Oligonucleotide (ΘGAATTCC) and 100000 to 200000 dpm of [³H]NAD for various times. Radiolabelled poly-ADP-ribose is measured by adding 50 to 500 ng of an anti polyADP-ribose antibody or an anti-PARP-1 antibody linked to scintillation proximity beads (Protein-A-beads, Amersham-Pharmacia). Bead bound radioactivity is measured in a Wallac Trilux Microbeta counter. Inhibition of PARP activity by compounds is calculated from control values in the absence of compounds and IG -values (concentration of compound yielding 50 % inhibition) are generated by nonlinear least square fitting.

The inhibitory values [measured as -loglC₅₀ (mol/l)] determined for the compounds according to the invention are shown in Table A. The numbers of the compounds corresponds to the numbers of the examples.

Table A: Inhibition of PARP-1 acitivitv [measured as -loglCso (mol/l)]

Claims

Patent claims

Compounds of the formula 1

wher ein

R1 is hydrogen or haloger ,

R2 represents a group selected from

wherein R3 is hydrogen, 1-4C-alkyl, 1-4C-alkoxycarbonyl or 1-4C-alkylsulfonyl-1-4C-alkyl, and the salts, the N-oxides and the salts of the N-oxides of these compounds.

2. Compounds of formula 1 according to claim 1 in which

R1 is hydrogen or fluorine,

R2 represents a group selected from

whereiπ R3 is hydrogen, butyl, tert.-butoxycarbonyl or methylsulfonylethyl, and the salts, the N-oxides and the salts of the N-oxides of these compounds.

3. Compounds of formula 1 according to claim 1 selected from 2-(4-Thiomorpholin-4-yl-phenyl)-4,5-dihydro-imidazo[4,5,1- /]quinolin-6-one; 2-(4-Morpholin-4-yl-phenyl)-4,5-dihydro-imidazo[4,5,1-/y]quinolin-6-one; 8-Fluoro-2-(4-morpholin-4-yl-phenyl)-4,5-dihydro-imidazo[4,5,1-/)]quinolin-6-one; 8-Fluoro-2-(4-thiomorpholin-4-yl-phenyl)-4,5-dihydro-imidazo[4,5,1-//]quinolin-6-oπe; 2-[4-(lOxo-1λ⁴-thiomorpholin-4-yl)-phenyl]-4,5-dihydro-imidazo[4,5,1- /]quinolin-6-one; 2-[4-(1 ,1-Dioxo-1λ⁶-thiomorpholin-4-yl)-phenyl]-4,5-dihydro-imidazo[4,5,1-//|quinolin-6-one; 2-[4-(1 ,1-Dioxo-1λ^B-thiomorpholin-4-yl)-phenyl]-8-fluoro-4,5-dihydro-imidazo[4,5,1-/)]quinolin-6-one; 4-[4-(6Oxo-5,6-dihydro-4/-/-imidazo[4,5,1-//]quinolin-2-yl)-phenyl]-piperazine-1-carboxylic acid tert-butyl ester;

4-[4-(8-Fluoro-6-oxo-5,6-dihydro-4/-/-imidazo[4,5,1-//]quinolin-2-yl)-phenyl]-piperazine-1-carboxylic acid tert- butyl ester;

2-(4-Piperazin-1-yl-phenyl)-4,5-dihydro-imidazo[4,5,1- /]quinolin-6-one; 8-Fluoro-2-(4-piperazin-1-yl-phenyl)-4,5-dihydro-imidazo[4,5,1-;/|quinolin-6-one; 2-{4-[4-(2-Methanesulfonyl-ethyl)-piperazin-1-yl]-phenyl}-4,5-dihydro-imidazo[4,5,1-;y]quiπolin-6-one; 2-[4-(4-Butyl-piperazin-1-yl)-phenyl]-4,5-dihydro-imidazo[4,5,1-/y]quinolin-6-one; and the salts, the N-oxides and the salts of the N-oxides of these compounds.

4. A compound of formula 1 as claimed in claim 1 for use in the treatment of diseases.

5. A pharmaceutical composition comprising at least one compound of formula 1 as claimed in claim 1 together with customary pharmaceutical excipients and/or vehicles.

6. Use of compounds of formula 1 as claimed in claim 1 for the production of pharmacutical compositions for treating cancer, inflammation, ischemia/reperfusion injury during organ transplantation surgery, cerebral stroke, myocardial infarct and diabetes mellitus.

7. A method of treating cancer, inflammation, ischemia/reperfusion injury during organ transplantation surgery, cerebral stroke, myocardial infarct or diabetes mellitus in a patient, comprising administering to said patient a therapeutically effective amount of a compound of formula 1 as claimed in claim 1.