2-Amino-imidazo[4,5-d]pyridazin-4-ones, their preparation and their use as pharmaceutical compositions

1. Compounds of formula I

wherein

R 1 denotes an arylmethyl or arylethyl group,

a heteroarylmethyl or heteroarylethyl group,

an arylcarbonylmethyl group,

a heteroarylcarbonylmethyl group or

an arylprop-2-enyl or heteroarylprop-2-enyl group, wherein the propenyl chain may be substituted by 1 to 4 fluorine atoms or a cyano, C 1-3 -alkyloxy-carbonyl or nitro group,

X denotes a nitrogen atom,

R 2 denotes a hydrogen atom,

a C 1-6 -alkyl group,

an aryl or heteroaryl group,

a C 1-6 -alkyl group substituted by a group R a , where

R a denotes a C 3-7 -cycloalkyl group wherein one or two methylene groups may each be replaced independently of one another by an oxygen or sulphur atom, by an —NH— or —N(C 1-3 -alkyl)- group or by a carbonyl, sulphinyl or sulphonyl group,

or a trifluoromethyl, aryl, heteroaryl, cyano, carboxy, C 1-3 -alkoxy-carbonyl, aminocarbonyl, C 1-3 -alkylamino-carbonyl, di-(C 1-3 -alkyl)-amino-carbonyl, pyrrolidin-1-ylcarbonyl, piperidin-1-ylcarbonyl, morpholin-4-ylcarbonyl, piperazin-1-ylcarbonyl, 4-(C 1-3 -alkyl)-piperazin-1-ylcarbonyl, arylcarbonyl, heteroarylcarbonyl, C 1-3 -alkylsulphinyl, C 1-3 -alkylsulphonyl, hydroxy, C 1-3 -alkoxy, C 1-3 -alkylsulphanyl, amino, C 1-3 -alkylamino, di-(C 1-3 -alkyl)-amino, pyrrolidin-1-yl, piperidin-1-yl, morpholin-4-yl, piperazin-1-yl or 4-(C 1-3 -alkyl)-piperazin-1-yl group,

a trifluoromethyl, carboxy, C 1-4 -alkoxy-carbonyl, aminocarbonyl, C 1-3 -alkylamino-carbonyl, di-(C 1-3 -alkyl)-amino-carbonyl, pyrrolidin-1-ylcarbonyl, piperidin-1-ylcarbonyl, morpholin-4-ylcarbonyl, piperazin-1-ylcarbonyl, 4-(C 1-3 -alkyl)-piperazin-1-ylcarbonyl, arylcarbonyl, heteroarylcarbonyl, C 1-3 -alkylsulphinyl, C 1-3 -alkylsulphonyl,

C 1-4 -alkoxy, C 1-4 -alkylsulphanyl, amino, C 1-3 -alkylamino or di-(C 1-3 -alkyl)-amino, pyrrolidin-1-yl, piperidin-1-yl, morpholin-4-yl, piperazin-1-yl or 4-(C 1-3 -alkyl)-piperazin-1-yl group,

a C 3-7 -cycloalkyl group wherein one or two methylene groups independently of one another may each be replaced by an oxygen or sulphur atom, by an —NH— or N(C 1-3 -alkyl)- group, or by a carbonyl, sulphinyl or sulphonyl group, or

a C 3-6 -alkenyl or C 3-6 -alkynyl group,

R 3 denotes a C 5-7 -cycloalkenylmethyl group optionally substituted by a C 1-3 -alkyl group,

an arylmethyl or heteroarylmethyl group,

a straight-chain or branched C 2-8 -alkenyl group which may be substituted by 1 to 15 fluorine atoms or a cyano, nitro or C 1-3 -alkoxy-carbonyl group,

or a straight-chain or branched C 3-8 -alkynyl group which may be substituted by 1 to 9 fluorine atoms or a cyano, nitro or C 1-3 -alkoxy-carbonyl group,

and

R 4 denotes an amino group substituted by the groups R 15 and R 16 wherein

R 15 denotes a hydrogen atom, a C 1-6 -alkyl, C 3-6 -cycloalkyl, C 3-6 -cycloalkyl-C 1-3 -alkyl, aryl or aryl-C 1-3 -alkyl group and

R 16 denotes a R 17 -C 2-3 -alkyl group, while the C 2-3 -alkyl moiety is straight-chain and may be substituted by 1 to 4 C 1-3 -alkyl groups, which may be identical or different, and

R 17 denotes an amino or C 1-3 -alkylamino group,

an amino group substituted by the groups R 15 and R 18 wherein

R 15 is as hereinbefore defined and R 18 denotes a C 3-10 -cycloalkyl-C 1-2 -alkyl-group substituted in the 1 position of the cycloalkyl group by R 19 or a C 3-10 -cyclo-alkyl group substituted in 1 or 2 position by a R 19 -C 1-2 -alkyl- group, while R 19 denotes an amino or C 1-3 -alkylamino group,

an amino group substituted by the groups R 15 and R 20 wherein

R 15 is as hereinbefore defined and R 20 denotes a C 4 - or C 8-10 -cycloalkyl group wherein a methylene group from position 3 onwards of the C 4 - or C 8-10 -cycloalkyl group is replaced by an —NH— group,

or an amino group substituted by the groups R 15 and R 21 wherein

R 15 is as hereinbefore defined and R 21 denotes a C 3-4 - or C 8-10 -cycloalkyl group substituted in the 2 or 3 position by an amino or C 1-3 -alkylamino group,

while the above-mentioned groups R 18 , R 20 and R 21 may be mono- or disubstituted by R b , the substituents may be identical or different and R b denotes a fluorine atom, a C 1-3 -alkyl, trifluoromethyl, cyano, amino, C 1-3 -alkylamino, hydroxy or C 1-3 -alkyloxy group, and wherein one or two methylene groups of the cycloalkyl group independently of one another may each be replaced by an oxygen or sulphur atom or by an —NH— or N(C 1-3 -alkyl)- group, or by a carbonyl, sulphinyl or sulphonyl group,

while by the aryl groups mentioned in the definition of the above groups are meant phenyl or naphthyl groups, which may be mono-, di- or trisubstituted independently of one another by R h , while the substituents may be identical or different and R h denotes a fluorine, chlorine, bromine or iodine atom, a trifluoromethyl, cyano, nitro, amino, aminocarbonyl, C 1-3 -alkoxy-carbonyl, aminosulphonyl, methylsulphonyl, acetylamino, methylsulphonylamino, C 1-3 -alkyl, cyclopropyl, ethenyl, ethynyl, morpholinyl, hydroxy, C 1-3 -alkyloxy, difluoromethoxy or trifluoromethoxy group, and wherein additionally each hydrogen atom may be replaced by a fluorine atom,

by the heteroaryl groups mentioned in the definition of the above-mentioned groups is meant a pyrrolyl, furanyl, thienyl, pyridyl, indolyl, benzofuranyl, benzothiophenyl, quinolinyl or isoquinolinyl group,

or is meant a pyrrolyl, furanyl, thienyl or pyridyl group, wherein one or two methyne groups are replaced by nitrogen atoms,

or is meant an indolyl, benzofuranyl, benzothiophenyl, quinolinyl or isoquinolinyl group, wherein one to three methyne groups are replaced by nitrogen atoms,

and the above-mentioned heteroaryl groups may be mono- or disubstituted by R h , while the substituents may be identical or different and R h is as hereinbefore defined,

by the above-mentioned cycloalkyl groups as defined are meant both monocyclic and also polycyclic ring systems, while the polycyclic groups may be annelated, spiro-linked or bridged in structure,

while, unless otherwise stated, the above-mentioned alkyl, alkenyl and alkynyl groups may be straight-chain or branched,

while the carboxy groups mentioned in the definition of the above-mentioned groups may be replaced by a group which may be converted in vivo into a carboxy group or by a group which is negatively charged under physiological conditions,

and the amino and imino groups mentionied in the definition of the above-mentioned groups may be substituted by a group which can be cleaved in vivo,

the tautomers, enantiomers, diastereomers, the mixtures thereof, and the salts thereof.

2. Compounds of formula I according to claim 1 ,

wherein

R 1 and R 4 are defined as mentioned in claim 1 ,

X denotes a nitrogen atom,

R 2 denotes a hydrogen atom, a C 1-4 alkyl, C 3-6 -cycloalkyl or phenyl group and

R 3 denotes a 1-buten-1-yl, 2-buten-1-yl, 2-butyn-1-yl, cyclopent-1-enyl-methyl, furanylmethyl, thienylmethyl, chlorobenzyl, bromobenzyl, iodobenzyl, methoxybenzyl or cyanobenzyl group,

the enantiomers, the diastereomers, the mixtures thereof and the salts thereof.

3. Compounds of formula I according to claim 2 ,

wherein

R 1 denotes a phenylmethyl, phenylcarbonylmethyl, phenylprop-2-enyl, pyridinylmethyl, pyrimidinylmethyl, naphthylmethyl, quinolinylmethyl, isoquinolinylmethyl, quinazolinylmethyl, quinoxalinylmethyl, naphthyridinylmethyl or benzotriazolylmethyl group which may be substituted in each case by one or two fluorine, chlorine, bromine atoms or one or two cyano, nitro, amino, C 1-3 -alkyl, C 1-3 -alkyloxy and morpholinyl groups, while the substituents are identical or different,

X denotes a nitrogen atom,

R 2 denotes a hydrogen atom,

R 3 denotes a 1-buten-1-yl, 2-buten-1-yl, 2-butyn-1-yl, cyclopent-1-enyl-methyl, furanylmethyl, thienylmethyl, chlorobenzyl, bromobenzyl, iodobenzyl or cyanobenzyl group and

R 4 denotes an N-(2-aminoethyl)-N-methyl-amino group wherein the ethyl group may be substituted by 1 to 4 methyl groups,

the tautomers, the mixtures thereof and the salts thereof.

4. Compounds of formula I according to claim 3 , wherein

R 1 denotes a isoquinolinylmethyl, quinazolinylmethyl or benzyl group which may be substituted by a methyl or cyano group,

X denotes a nitrogen atom,

R 2 denotes a hydrogen atom,

R 3 denotes a 2-butyn-1-yl group and

R 3 denotes an N-(2-aminoethyl)-N-methyl-amino, N-(2-aminopropyl)-N-methyl-amino or N-(2-amino-2-methylpropyl)-N-methyl-amino group,

the tautomers and the salts thereof.

5. The following compounds of formula I according to claim 1 :

(a) 2-[N-(2-aminoethyl)-N-methyl-amino]-3-(2-butyn-1-yl)-5-[(4-methyl-quinazolin-2-yl)methyl]-3,5-dihydro-imidazo[4,5-d]pyridazin-4-one

(b) 2-[N-(2-aminoethyl)-N-methyl-amino]-3-(2-butyn-1-yl)-5-[(3-methyl-isoquinolin-1-yl)methyl]-3,5-dihydro-imidazo[4,5-d]pyridazin-4-one

(c) (S)-2-[N-(2-aminopropyl)-N-methyl-amino]-3-(2-butyn-1-yl)-5-(2-cyanophenyl-methyl)-3,5-dihydro-imidazo[4,5-d]pyridazin-4-one

(d) 2-[N-(2-amino-2-methyl propyl)-N-methyl-amino]-3-(2-butyn-1-yl )-5-(2-cyanophenylmethyl) -3,5-dihydro-imidazo[4,5-d]pyridazin-4-one

(e) (S)-2-[N-(2-aminopropyl)-N-methyl-amino]-3-(2-butyn-1-yl)-5-[(4-methyl-quinazolin-2-yl)methyl]-3,5-dihydro-imidazo[4,5-d]pyridazin-4-one

(f) (S)-2-[N-(2-amino-propyl )-N-methyl-amino]-3-(2-butyn- I -yl)-5-(4-cyano-isoquinolin-3-ylmethyl) -3,5-dihydro-imidazo[4,5-d]pyridazin-4-one

as well as the tautomers and the salts thereof.

6. A pharmaceutical composition comprising the compound according to claim 1 or a physiologically acceptable salt thereof together with one or more inert carriers and/or diluents.

7. Process for preparing the compounds of formula I according to claim 1 , the process comprising

a) providing a compound of general formula II

wherein

R 1 to R 3 and X are defined as mentioned in claim 1 and

Z 1 denotes a leaving group such as a halogen atom, a substituted hydroxy, mercapto, sulphinyl, sulphonyl or sulphonyloxy group, and

b) reacting the compound of general formula II with R 4 -H or salts thereof, where R 4 is defined as in claim 1 .

8. Process for preparing the compounds of formula I according to claim 1 , the process comprising

a) deprotecting a compound of formula Ill

wherein R 1 , R 2 , R 3 and X are defined as mentioned in claim 1 and Z 2 denotes one of the groups mentioned for R 4 in claim 1 that contains an amino group not directly linked to the basic imidazopyridazinone structure, and wherein said amino group not directly linked to the basic imidazopyridazinone structure is protected by a tertbutyloxycarbonyl group.

9. The process according to claim 7 further comprising:

cleaving any protecting groups used during the reaction,

resolving the compounds of formula I thus obtained into their enantiomers or diastereomers and

converting the compounds of formula I thus obtained into their salts with inorganic or organic acids or bases.

10. The process according to claim 8 further comprising:

cleaving any protecting groups used during the reaction,

resolving the compounds of formula I thus obtained into their enantiomers or diastereomers and

converting the compounds of formula I thus obtained into their salts with inorganic or organic acids or bases.