Trisubstituted pyrimidines

Abstract

The present invention relates to trisubstituted pyrimidines of formula wherein R a to R e are defined as in claim 1, which are suitable for the treatment of illnesses in which β-amyloid modulators have a therapeutic benefit, the use thereof for preparing a pharmaceutical composition with the abovementioned properties, and processes for the preparation thereof.

1 . A trisubstituted pyrimidine of formula (I)  
       
         
           
           
               
               
           
         
       
       wherein 
 R a  denotes a hydrogen atom or an alkyl group,  
 R b  denotes a phenyl group substituted by the groups R 1  to R 5 , while 
 R 1  denotes a hydrogen, fluorine, chlorine, bromine or iodine atom, 
 a C 1-6 -alkyl, hydroxy or C 1-6 -alkoxy group,  
 a C 3-7 -cycloalkyl, C 4-7 -cycloalkoxy or (C 3-7 -cycloalkyl)alkyl group, which may be substituted in the cycloalkyl moiety by one or two alkyl groups in each case,  
 a C 2-5 -alkenyl, C 3-5 -alkenyloxy, C 2-5 -alkynyl or C 3-5 -alkynyloxy group, wherein the vinyl and ethynyl moieties cannot be linked with an oxygen atom, an aryl, aryloxy, arylalkyl, arylalkoxy, alkylsulphenyl, alkylsulphinyl, alkylsulphonyl, alkylsulphonyloxy, arylsulphenyl, arylsulphinyl, arylsulphonyl, arylalkylsulphenyl, arylalkylsulphinyl or arylalkylsulphonyl group,  
 a methyl, methoxy, methylsulphenyl, methylsulphinyl or methylsulphonyl group substituted by 1 to 3 fluorine atoms,  
 an ethyl, ethoxy, ethylsulphenyl, ethylsulphinyl or ethylsulphonyl group substituted by 1 to 5 fluorine atoms,  
 a nitro, amino, alkylamino, dialkylamino or azido group,  
 an 4- to 7-membered alkyleneimino group optionally substituted by one or two alkyl groups,  
 an 6 or 7-membered alkyleneimino group optionally substituted by one or two alkyl groups, wherein a methylene group in the 4 position to the imino-nitrogen atom is replaced by the group W, where 
 W denotes an oxygen or sulphur atom, a sulphinyl, sulphonyl, imino, N-alkyl-imino, N-formyl-imino, N-alkylcarbonyl-imino, N-cyano-imino, N-alkoxycarbonyl-imino or N-alkylsulphonyl-imino group,  
 
 a formylamino, N-alkyl-formylamino, alkylcarbonylamino, N-alkyl-alkylcarbonylamino, alkylsulphonylamino or N-alkyl-alkylsulphonylamino group,  
 an alkylcarbonyl, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl or cyano group,  
 an aminosulphonyl, alkylaminosulphonyl or dialkylaminosulphonyl group,  
 an alkyl or alkoxy group substituted by R 9 , wherein 
 R 9  denotes a hydroxy, alkoxy, amino, alkylamino, dialkylamino, alkylsulphenyl, alkylsulphinyl, alkylsulphonyl, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl or cyano group,  
  a 4- to 7-membered alkyleneiminocarbonyl group optionally substituted by one or two alkyl groups,  
  a 6 or 7-membered alkyleneiminocarbonyl group optionally substituted by one or two alkyl groups, wherein a methylene group in the 4 position of the alkyleneimino moiety is replaced by the group W, where W is as hereinbefore defined,  
  a 4- to 7-membered alkyleneimino group optionally substituted by one or two alkyl groups,  
  a 5- to 7-membered alkyleneimino group optionally substituted by one or two alkyl groups, wherein a methylene group adjacent to the nitrogen atom is replaced by a carbonyl group,  
  a 6- or 7-membered alkyleneimino group optionally substituted by one or two alkyl groups, wherein a methylene group in the 4 position is replaced by the group W, where W is as hereinbefore defined,  
  a formylamino, N-alkyl-formylamino, alkylcarbonylamino, N-alkyl-alkylcarbonylamino, alkylsulphonylamino, N-alkyl-alkylsulphonylamino, perfluoralkylsulphonylamino, N-alkyl-perfluoralkylsulphonylamino, alkoxycarbonylamino, N-alkyl-alkoxycarbonylamino, cyanoamino or N-alkyl-cyanoamino group,  
 
 
 R 2  and R 3  in each case independently of one another denote hydrogen, fluorine, chlorine, bromine or iodine atoms, alkyl, alkoxy, fluoroalkyl, fluoroalkoxy or cyano groups or  
 R 2  together with R 3 , if they are bound to adjacent carbon atoms, also a methylenedioxy group optionally substituted by one or two alkyl groups, an n-C 3-6 -alkylene group optionally substituted by one or two alkyl groups, wherein a methylene group may be replaced by the group W′, where W′ has the meanings given above for W and additionally denotes a trifluoroacetylimino group, a 1,3-butadiene-1,4-diylene group optionally substituted by a fluorine, chlorine, bromine or iodine atom, by an alkyl, trifluoromethyl, hydroxy, alkoxy, trifluoromethoxy or cyano group, while the abovementioned 1,3-butadiene-1,4-diylene groups may additionally be substituted by a fluorine or chlorine atom, by an alkyl, trifluoromethyl or alkoxy group,  
 R 4  and R 5  in each case independently of one another denote hydrogen, fluorine or chlorine atoms or  
 R 4  together with R a , if R 4  is in the o-position to the nitrogen atom substituted by R a , also denote an n-C 2-4 -alkylene group optionally substituted by one or two alkyl groups,  
 
 R c  denotes a C 1-6 -alkyl group optionally mono- or polysubstituted by R 9 , while R 9  is as hereinbefore defined, 
 a methyl group substituted by a fluoromethyl, chloromethyl, bromomethyl, difluoromethyl or trifluoromethyl group,  
 a C 3-7 -cycloalkyl, (C 3-7 -cycloalkyl)alkyl or arylalkyl group,  
 a C 3-5 -alkenyl or C 3-5 -alkynyl group, wherein the vinyl and ethynyl moieties cannot be linked to the nitrogen atom of the R c NR d  group,  
 
 R d  denotes a hydrogen atom or an alkyl group, or  
 R c  together with Rd and the nitrogen atom attached to them denote a 3- to 7-membered alkyleneimino group or a 6 or 7-membered alkyleneimino group, wherein a methylene group in the 4 position is replaced by the group W, where W is as hereinbefore defined, and  
 R e  denotes a nitro, amino, alkylamino, dialkylamino or azido group, 
 a 4- to 7-membered alkyleneimino group optionally substituted by one or two alkyl groups, wherein one or two methylene group adjacent to the nitrogen atoms may be replaced by a carbonyl group, while additionally in this alkyleneimino group a CH 2  group in the 4 position may be replaced by the group W where W is as hereinbefore defined,  
 a formylamino, N-alkyl-formylamino, alkylcarbonylamino, N-alkyl-alkylcarbonylamino, di(alkylcarbonyl)amino, (C 3-7 -cycloalkyl)carbonylamino, N-alkyl-(C 3-7 -cycloalkyl)carbonylamino, (C 3-7 -cycloalkyl)alkylcarbonylamino, N-alkyl-(C 3-7 -cycloalkyl)alkylcarbonylamino, arylcarbonylamino, N-alkyl-arylcarbonylamino, arylalkylcarbonylamino, N-alkyl-arylalkylcarbonylamino, heteroarylcarbonylamino, N-alkyl-heteroarylcarbonylamino, heteroarylalkylcarbonylamino, N-alkyl-heteroarylalkylcarbonylamino, alkoxycarbonylamino, N-alkyl-alkoxycarbonylamino, arylalkoxycarbonylamino, N-alkyl-arylalkoxycarbonylamino, aryloxycarbonylamino, N-alkyl-aryl-oxycarbonylamino, (C 4-7 -cycloalkoxy)carbonylamino, N-alkyl-(C 4-7 -cycloalkoxy)carbonylamino, (C 3-7 -cycloalkyl)alkoxycarbonylamino, N-alkyl-(C 3-7 -cycloalkyl)alkoxycarbonylamino, alkylsulphonylamino, N-alkyl-alkylsulphonylamino, di(alkylsulphonyl)amino, C 3-7 -cycloalkylsulphonylamino, N-alkyl-C 3-7 -cycloalkylsulphonylamino, (C 3-7 -cycloalkyl)alkylsulphonylamino, N-alkyl-(C 3-7 -cycloalkyl)alkylsulphonylamino, arylsulphonylamino, N-alkyl-arylsulphonylamino, arylalkylsulphonylamino, N-alkyl-arylalkylsulphonylamino, heteroarylsulphonylamino, N-alkyl-heteroarylsulphonylamino, heteroarylalkylsulphonylamino, N-alkyl-heteroarylalkylsulphonylamino, cyanoamino or N-alkyl-cyanoamino group, while additionally the alkyl moieties and cycloalkyl moieties in the abovementioned groups may be substituted by the group R 9 , while R 9  is as hereinbefore defined, and the cycloalkyl moieties may additionally be substituted by one or two alkyl groups,  
 a (C 5-7 -cycloalkyl)carbonylamino, N-alkyl-(C 5-7 -cycloalkyl)carbonylamino, (C 5-7 -cycloalkyl)alkylcarbonylamino or N-alkyl-(C 5-7 -cycloalkyl)alkylcarbonylamino group, while the cycloalkyl moieties may in each case be substituted by one or two alkyl groups and additionally a methylene group in the cycloalkyl moieties of the abovementioned groups is replaced by the group W, where W is as hereinbefore defined,  
 a C 2-5 -alkenylcarbonylamino, N-alkyl-C 2-5 -alkenylcarbonylamino, C 2-5 -alkynylcarbonylamino, N-alkyl-C 2-5 -alkynylcarbonylamino, perfluoroalkylcarbonylamino, N-alkyl-perfluoroalkylcarbonylamino, perchloroalkylcarbonylamino, N-alkyl-perchloroalkylcarbonylamino, perfluoroalkylsulphonylamino or N-alkyl-perfluoroalkylsulphonylamino group,  
 an alkyleneiminocarbonylamino or N-alkyl-alkyleneiminocarbonylamino group optionally substituted in the alkyleneimino moiety by one or two alkyl groups, while the alkyleneimino moiety is 4 to 7-membered in each case,  
 an alkyleneiminocarbonylamino or N-alkyl-alkyleneiminocarbonylamino group optionally substituted in the alkyleneimino moiety by one or two alkyl groups, while the alkyleneimino moiety is 6 or 7-membered in each case and a methylene group in the 4 position of the alkyleneimino moiety is replaced in each case by the group W, where W is as hereinbefore defined,  
 an alkyleneiminothiocarbonylamino or N-alkyl-alkyleneiminothiocarbonylamino group optionally substituted in the alkyleneimino moiety by one or two alkyl groups, while the alkyleneimino moiety is 4 to 7-membered in each case,  
 an alkyleneiminothiocarbonylamino or N-alkyl-alkyleneiminothiocarbonylamino group optionally substituted in the alkyleneimino moiety by one or two alkyl groups, while the alkyleneimino moiety in each case is 6 or 7-membered and a methylene group in the 4 position of the alkyleneimino moiety is replaced in each case by the group W, where W is as hereinbefore defined,  
 a R 7 NR 8 —CO—NR 6  or R 7 NR 8 —SO 2 —NR 6 -group, wherein 
 R 6  denotes a hydrogen atom or an alkyl group,  
 R 7  and R 8  in each case independently of one another denote hydrogen atoms or alkyl groups optionally substituted by R 9 , or  
 R 6  and R 7  together denote an n-C 2-3 -alkylene group and  
 R 8  denotes a hydrogen atom or an alkyl group optionally substituted by R 9 , while R 9  is as hereinbefore defined, 
 an imidazolidine-2,4-dion-1-yl or imidazolidine-2,4-dion-3-yl-group optionally substituted by 1 to 3 alkyl groups, while one of the alkyl groups may be substituted by R 9 ,  
 a 1,3-dihydro-imidazol-2-on-1-yl group optionally substituted by 1 to 3 alkyl groups, while one of the alkyl groups may be substituted by R 9 ,  
 a 2,4-dihydro-1,2,4-triazol-3-on-2-yl or 2,4-dihydro-1,2,4-triazol-3-on-4-yl-group optionally substituted by 1 or 2 alkyl groups, while one of the alkyl groups may be substituted by R 9 ,  
 
 
 a (R 14 NR 15 )—R 13 C═N-group wherein 
 R 13  denotes a hydrogen atom, an alkyl or C 3-7 -cycloalkyl group,  
 R 14  and R 15  in each case independently of one another denote an alkyl group, or  
 R 14  and R 15  together with the nitrogen atom between them denote a 4- to 7-membered alkyleneimino group optionally substituted by one or two alkyl groups or a 6- or 7-membered alkyleneimino group optionally substituted by one or two alkyl groups, wherein a methylene group in the 4 position is replaced by the group W, where W is as hereinbefore defined, and  
 R 13  denotes a hydrogen atom, an alkyl or C 3-7 -cycloalkyl group,  
 
 a (R 18 N═)CR 16 —R 17 N-group wherein 
 R 16  denotes a hydrogen atom, an alkyl, C 3-7 -cycloalkyl, trifluoromethyl or trichloromethyl group,  
 R 17  and R 18 , which may be identical or different, in each case represent a hydrogen atom or an alkyl group or  
 R 16  and R 18  together represent an n-C 3-5 -alkylene group optionally substituted by one or two alkyl groups and  
 R 17  represents a hydrogen atom or an alkyl group or  
 R 17  and R 18  together represent an n-C 2-4 -alkylene group optionally substituted by one or two alkyl groups and  
 R 16  denotes a hydrogen atom, an alkyl or C 3-7 -cycloalkyl group,  
 an (R 19 R 20 PO)—NH-group optionally substituted at the nitrogen atom by an alkyl group, wherein 
 R 19  and R 20 , which may be identical or different, denote alkyl or aryl groups, a alkyl or alkoxy group substituted by R 9 , wherein R 9  is as hereinbefore defined, a formyl, alkylcarbonyl, 1-(hydroxyimino)alkyl, 1-(alkoxyimino)alkyl, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl or cyano group,  
 
 
 a sulpho, alkoxysulphonyl, aminosulphonyl, alkylaminosulphonyl or dialkylaminosulphonyl group,  
 a 4- to 7-membered alkyleneiminocarbonyl or alkyleneiminosulphonyl group optionally substituted by one or two alkyl groups,  
 a 6- or 7-membered alkyleneiminocarbonyl or alkyleneiminosulphonyl group optionally substituted by one or two alkyl groups, wherein a methylene group of the alkyleneimino moiety is replaced in the 4 position by the group W, where W is as hereinbefore defined,  
 a heteroaryl or heteroarylalkyl group,  
 an alkoxy-C(═NH) or alkylsulphenyl-C(═NH)-group optionally substituted at the nitrogen atom by an alkyl group,  
 an R 10 N═C(OR 11 ), R 10 N═C(SR 11 ), R 10 N═C(NHR 11 ) or R 10 N═C(N-alkyl-NR 11 )-group, wherein 
 R 10  and R 11  together denote an n-C 2-4 -alkylene group optionally substituted by one or two alkyl groups,  
 
 an amidino group optionally substituted by one to three alkyl groups or an amidino group substituted by a hydroxy, alkoxy, cyano, alkoxycarbonyl or arylalkoxycarbonyl group, which may additionally be substituted at the nitrogen atoms by one or two alkyl groups,  
 
 or a tautomer, stereoisomer or physiologically acceptable salt thereof,  
 wherein, unless otherwise stated,  
 the aryl moieties set forth above, either alone or as part of another group, each independently mean a phenyl group which in each case is optionally monosubstituted by R 21 , mono-, di- or trisubstituted by R 22  or monosubstituted by R 21  and additionally mono- or disubstituted by R 22 , wherein the substituents may be identical or different, and  
 R 21  denotes a cyano, carboxy, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, alkoxycarbonyl, alkylcarbonyl, alkylsulphenyl, alkylsulphinyl, alkylsulphonyl, alkylsulphonyloxy, perfluoroalkyl, perfluoroalkoxy, nitro, amino, alkylamino, dialkylamino, alkylcarbonylamino, phenylalkylcarbonylamino, phenylcarbonylamino, alkylsulphonylamino, phenylalkylsulphonylamino, phenylsulphonylamino, N-alkyl-alkylcarbonylamino, N-alkyl-phenylalkylcarbonylamino, N-alkyl-phenylcarbonylamino, N-alkyl-alkylsulphonylamino, N-alkyl-phenylalkylsulphonylamino, N-alkyl-phenylsulphonylamino, amino sulphonyl, alkylaminosulphonyl, dialkylaminosulphonyl, pyrrolidino, piperidino, morpholino, piperazino or 4-alkyl-piperazino group and  
 R 22  denotes an alkyl, hydroxy or alkoxy group, a fluorine, chlorine, bromine or iodine atom, while two groups R 22  if they are bound to adjacent carbon atoms, may also denote an alkylene group with 3 to 6 carbon atoms, a 1,3-butadiene-1,4-diylene group or a methylenedioxy group,  
 wherein the heteroaryl moieties set forth above, either alone or as part of another group, each independently mean a 5-membered heteroaromatic ring with an imino group, an oxygen or sulphur atom in the ring or a 5-membered heteroaromatic ring with an oxygen or sulphur atom and one to two nitrogen atoms in the ring or a 5-membered heteroaromatic ring with an imino group and one to three nitrogen atoms in the ring or a 6-membered heteroaromatic ring with one to three nitrogen atoms in the ring, wherein the abovementioned 5- and 6-membered heteroaromatic rings may be optionally substituted by one to two alkyl groups or by a trifluoromethyl group,  
 and, unless otherwise stated, the abovementioned alkyl, alkylene and alkoxy moieties in each case contain 1 to 4 carbon atoms.  
 
     
     
         2 . A trisubstituted pyrimidine of formula (I)  
       
         
           
           
               
               
           
         
       
       wherein 
 R a  denotes a hydrogen atom or an alkyl group,  
 R b  denotes a phenyl group substituted by the groups R 1  to R 5 , while 
 R 1  denotes a hydrogen, fluorine, chlorine, bromine or iodine atom, 
 a C 1-6 -alkyl, hydroxy or C 1-6 -alkoxy group,  
 a C 3-6 -cycloalkyl, C 5-6 -cycloalkoxy or (C 3-6 -cycloalkyl)alkyl group, which may be substituted in the cycloalkyl moiety by one or two alkyl groups in each case,  
 a C 2-5 -alkenyl, C 3-5 -alkenyloxy, C 2-5 -alkynyl or C 3-5 -alkynyloxy group, wherein the vinyl and ethynyl moieties cannot be linked with an oxygen atom, an aryl, aryloxy, arylalkyl, arylalkoxy, alkylsulphenyl, alkylsulphinyl, alkylsulphonyl, alkylsulphonyloxy, arylsulphenyl, arylsulphinyl, arylsulphonyl, arylalkylsulphenyl, arylalkylsulphinyl or arylalkylsulphonyl group,  
 a methyl, methoxy, methylsulphenyl, methylsulphinyl or methylsulphonyl group substituted by 1 to 3 fluorine atoms,  
 an ethyl, ethoxy, ethylsulphenyl, ethylsulphinyl or ethylsulphonyl group substituted by 1 to 5 fluorine atoms,  
 a nitro, amino, alkylamino, dialkylamino or azido group,  
 a 5- to 6-membered alkyleneimino group optionally substituted by one or two alkyl groups,  
 a 6- or 7-membered alkyleneimino group optionally substituted by one or two alkyl groups, wherein a methylene group in the 4 position to the imino-nitrogen atom is replaced by the group W, where 
 W denotes an oxygen or sulphur atom, a sulphinyl, sulphonyl, imino, N-alkyl-imino, N-formyl-imino, N-alkylcarbonyl-imino, N-cyan-imino, N-alkoxycarbonyl-imino or N-alkylsulphonyl-imino group,  
 
 a formylamino, N-alkyl-formylamino, alkylcarbonylamino, N-alkyl-alkylcarbonylamino, alkylsulphonylamino or N-alkyl-alkylsulphonylamino group, an alkylcarbonyl, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl or cyano group,  
 an aminosulphonyl, alkylaminosulphonyl or dialkylaminosulphonyl group,  
 an alkyl or alkoxy group substituted by R 9 , wherein 
 R 9  denotes a hydroxy, alkoxy, amino, alkylamino, dialkylamino, alkylsulphenyl, alkylsulphinyl, alkylsulphonyl, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl or cyano group,  
 
 a 4- to 7-membered alkyleneimino group optionally substituted by one or two alkyl groups,  
 a 6- or 7-membered alkyleneimino group optionally substituted by one or two alkyl groups, wherein a methylene group in the 4 position is replaced by the group W, where W is as hereinbefore defined,  
 a formylamino, N-alkyl-formylamino, alkylcarbonylamino, N-alkyl-alkylcarbonylamino, alkylsulphonylamino, N-alkyl-alkylsulphonylamino, perfluoroalkylsulphonylamino, N-alkyl-perfluoroalkylsulphonylamino, alkoxycarbonylamino, N-alkyl-alkoxycarbonylamino, cyanoamino or N-alkyl-cyanoamino group,  
 
 R 2  and R 3  in each case independently of one another denote hydrogen, fluorine, chlorine, bromine or iodine atoms, alkyl, alkoxy, trifluoromethyl, trifluoromethoxy, difluoromethyl, difluoromethoxy or cyano groups or  
 R 2  together with R 3 , if they are bound to adjacent carbon atoms, also denote a methylenedioxy group optionally substituted by one or two alkyl groups, an n-C 3-6 -alkylene group optionally substituted by one or two alkyl groups, wherein a methylene group may be replaced by the group W′, where W′ has the meanings given above for W and additionally denotes a trifluoroacetylimino group, a 1,3-butadiene-1,4-diylene group optionally substituted by a fluorine, chlorine, bromine or iodine atom, by an alkyl, trifluoromethyl, hydroxy, alkoxy, trifluoromethoxy or cyano group, while the abovementioned 1,3-butadiene-1,4-diylene groups may additionally be substituted by a fluorine or chlorine atom, by an alkyl, trifluoromethyl or alkoxy group,  
 R 4  and R 5 , which may be identical or different, denote hydrogen, fluorine or chlorine atoms,  
 
 R c  denotes a C 1-6 -alkyl group, which may be substituted by one or more hydroxy, alkoxy, dialkylamino groups,  
 R d  denotes a hydrogen atom or a C 1-6 -alkyl group, and  
 R e  denotes a nitro, amino, alkylamino, dialkylamino or azido group, 
 a 5- to 7-membered alkyleneimino group optionally substituted by one or two alkyl groups,  
 a 5- to 7-membered alkyleneimino group optionally substituted by one or two alkyl groups, wherein one or two methylene groups adjacent to the nitrogen atoms may be replaced by a carbonyl group, while additionally in the alkyleneimino group a methylene group in the 4 position to the imino-nitrogen atom may be replaced by the group W where W is as hereinbefore defined,  
 a formylamino, N-alkyl-formylamino, alkylcarbonylamino, N-alkyl-alkylcarbonylamino, di(alkylcarbonyl)amino, (C 3-7 -cycloalkyl)carbonylamino, N-alkyl-(C 3-7 -cycloalkyl)carbonylamino, (C 3-7 -cycloalkyl)alkylcarbonylamino, N-alkyl-(C 3-7 -cycloalkyl)alkylcarbonylamino, arylcarbonylamino, N-alkyl-arylcarbonylamino, arylalkylcarbonylamino, N-alkyl-arylalkylcarbonylamino, heteroarylcarbonylamino, N-alkyl-heteroarylcarbonylamino, heteroarylalkylcarbonylamino, N-alkyl-heteroarylalkylcarbonylamino, alkoxycarbonylamino, N-alkyl-alkoxycarbonylamino, arylalkoxycarbonylamino, N-alkyl-arylalkoxycarbonylamino, aryloxycarbonylamino, N-alkyl-aryl-oxycarbonylamino, (C 4-7 -cycloalkoxy)carbonylamino, N-alkyl-(C 4-7 -cycloalkoxy)carbonylamino, (C 3-7 -cycloalkyl)alkoxycarbonylamino, N-alkyl-(C 3-7 -cycloalkyl)alkoxycarbonylamino, alkylsulphonylamino, N-alkyl-alkylsulphonylamino, di(alkylsulphonyl)amino, C 3-7 -cycloalkylsulphonylamino, N-alkyl-C 3-7 -cycloalkylsulphonylamino, (C 3-7 -cycloalkyl)alkylsulphonylamino, N-alkyl-(C 3-7 -cycloalkyl)alkylsulphonylamino, arylsulphonylamino, N-alkyl-arylsulphonylamino, arylalkylsulphonylamino, N-alkyl-arylalkylsulphonylamino, heteroarylsulphonylamino, N-alkyl-heteroarylsulphonylamino, heteroarylalkylsulphonylamino, N-alkyl-heteroarylalkylsulphonylamino, cyanoamino or N-alkyl-cyanoamino group, while in each case the alkyl moiety of these groups may be substituted by the group R 9  and R 9  is as hereinbefore defined, and the cycloalkyl moieties of these groups may be substituted by one or two alkyl groups and additionally a CH 2  group in the cycloalkyl moieties of the abovementioned groups is replaced by the group W, where W is as hereinbefore defined,  
 a C 2-5 -alkenylcarbonylamino, N-alkyl-C 2-5 -alkenylcarbonylamino, C 2-5 -alkynylcarbonylamino, N-alkyl-C 2-5 -alkynylcarbonylamino, perfluoroalkylcarbonylamino, N-alkyl-perfluoroalkylcarbonylamino, perchloroalkylcarbonylamino, N-alkyl-perchloroalkylcarbonylamino, perfluoroalkylsulphonylamino or N-alkyl-perfluoroalkylsulphonylamino group, an alkyleneiminocarbonylamino or N-alkyl-alkyleneiminocarbonylamino group optionally substituted in the alkyleneimino moiety by one or two alkyl groups, while the alkyleneimino moiety is 4- to 7-membered in each case,  
 an alkyleneiminocarbonylamino or N-alkyl-alkyleneiminocarbonylamino group optionally substituted in the alkyleneimino moiety by one or two alkyl groups, while the alkyleneimino moiety is 6- or 7-membered in each case and a methylene group in the 4 position of the alkyleneimino moiety is in each case replaced by the group W, where W is as hereinbefore defined,  
 an alkyleneiminothiocarbonylamino or N-alkyl-alkyleneiminothiocarbonylamino group optionally substituted in the alkyleneimino moiety by one or two alkyl groups, while the alkyleneimino moiety is 4- to 7-membered in each case, an alkyleneiminothiocarbonylamino or N-alkyl-alkyleneiminothiocarbonylamino group optionally substituted in the alkyleneimino moiety by one or two alkyl groups, while the alkyleneimino moiety is 6- or 7-membered in each case and in each case a methylene group in the 4 position of the alkyleneimino moiety is replaced by the group W, where W is as hereinbefore defined,  
 a R 7 NR 8 —CX—NR 6  or R 7 NR 8 —SO 2 —NR 6 -group, wherein 
 R 6  denotes a hydrogen atom or an alkyl group,  
 R 7  and R 8 , which may be identical or different, denote hydrogen atoms or alkyl groups optionally substituted by R 9  or  
 R 6  and R 7  together denote an n-C 2-3 -alkylene group and  
 R 8  denotes a hydrogen atom or an alkyl group optionally substituted by R 9 , while R 9  is as hereinbefore defined, and  
 X denotes O or S,  
 
 an imidazolidine-2,4-dion-1-yl or imidazolidine-2,4-dion-3-yl-group optionally substituted by an alkyl group,  
 a (R 14 NR 15 )—R 13 C═N-group wherein 
 R 13  denotes a hydrogen atom, an alkyl or C 3-7 -cycloalkyl group,  
 R 14  and R 15 , which may be identical or different, in each case denote an alkyl group, or  
 R 14  and R 15  together with the nitrogen atom between them denote a 4- to 7-membered alkyleneimino group optionally substituted by one or two alkyl groups or a 6- or 7-membered alkyleneimino group optionally substituted by one or two alkyl groups, wherein a methylene group in the 4 position is replaced by the group W, where W is as hereinbefore defined, and  
 R 13  denotes a hydrogen atom, an alkyl or C 3-7 -cycloalkyl group,  
 
 a (R 18 N═)CR 16 —R 17 N-group, wherein 
 R 16  denotes a hydrogen atom, an alkyl, C 3-7 -cycloalkyl, trifluoromethyl or trichloromethyl group,  
 R 17  and R 18  in each case independently of one another denote a hydrogen atom or an alkyl group, or  
 R 16  and R 18  together denote an n-C 3-5 -alkylene group optionally substituted by one or two alkyl groups, and  
 R 17  denotes a hydrogen atom or an alkyl group, or  
 R 17  and R 18  together denote an n-C 2-4 -alkylene group optionally substituted by one or two alkyl groups, and  
 R 16  denotes a hydrogen atom, an alkyl or C 3-7 -cycloalkyl group,  
 
 an (R 19 R 20 PO)—NH-group optionally substituted at the nitrogen atom by an alkyl group wherein 
 R 19  and R 20 , which may be identical or different, denote alkyl groups, an alkyl or alkoxy group substituted by R 9 , wherein R 9  is as hereinbefore defined, a formyl, alkylcarbonyl, 1-(hydroxyimino)alkyl, 1-(alkoxyimino)alkyl, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl or cyano group,  
 
 a sulpho, alkoxysulphonyl, aminosulphonyl, alkylaminosulphonyl or dialkylaminosulphonyl group,  
 a 4- to 7-membered alkyleneiminocarbonyl or alkyleneiminosulphonyl group optionally substituted by one or two alkyl groups,  
 a 6 or 7-membered alkyleneiminocarbonyl or alkyleneiminosulphonyl group optionally substituted by one or two alkyl groups, wherein a methylene group of the alkyleneimino moiety in the 4 position is replaced by the group W, where W is as hereinbefore defined,  
 a heteroaryl or heteroarylalkyl group,  
 an alkoxy-C(═NH) or alkylsulphenyl-C(═NH)-group optionally substituted at the nitrogen atom by an alkyl group,  
 an R 10 N═C(OR 11 ), R 10 N═C(SR 11 ), R 10 N═C(NHR 11 ) or R 10 N═C(N-alkyl-NR 11 )-group, wherein 
 R 10  and R 11  together denote an n-C 2-4 -alkylene group optionally substituted by one or two alkyl groups,  
 
 an amidino group optionally substituted by one to three alkyl groups or  
 an amidino group substituted by a hydroxy, alkoxy, cyano, alkoxycarbonyl or arylalkoxycarbonyl group, which may additionally be substituted at the nitrogen atoms by one or two alkyl groups,  
 wherein the aryl moieties set forth above, either alone or as part of another group, each independently mean a phenyl group which in each case is optionally monosubstituted by R 21 , mono-, di- or trisubstituted by R 22  or monosubstituted by R 21  and additionally mono- or disubstituted by R 22 , while the substituents may be identical or different, and  
 
 R 21  denotes a cyano, carboxy, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, alkoxycarbonyl, alkylcarbonyl, alkylsulphenyl, alkylsulphinyl, alkylsulphonyl, alkylsulphonyloxy, perfluoroalkyl, perfluoroalkoxy, nitro, amino, alkylamino, dialkylamino, alkylcarbonylamino, phenylalkylcarbonylamino, phenylcarbonylamino, alkylsulphonylamino, phenylalkylsulphonylamino, phenylsulphonylamino, N-alkyl-alkylcarbonylamino, N-alkyl-phenylalkylcarbonylamino, N-alkyl-phenylcarbonylamino, N-alkyl-alkylsulphonylamino, N-alkyl-phenylalkylsulphonylamino, N-alkyl-phenylsulphonylamino, aminosulphonyl, alkylaminosulphonyl, dialkylaminosulphonyl, pyrrolidino, piperidino, morpholino, piperazino or 4-alkyl-piperazino group and  
 R 22  denotes an alkyl, hydroxy or alkoxy group, a fluorine, chlorine, bromine or iodine atom, while two groups R 22 , if they are bound to adjacent carbon atoms, may also denote an alkylene group with 3 to 6 carbon atoms, a 1,3-butadiene-1,4-diylene group or a methylenedioxy group,  
 wherein the heteroaryl moieties set forth above, either alone or as part of another group, each independently mean a 5-membered heteroaromatic ring with an imino group, an oxygen or sulphur atom in the ring or a 5-membered heteroaromatic ring with an oxygen or sulphur atom and one to two nitrogen atoms in the ring or a 5-membered heteroaromatic ring with an imino group and one to three nitrogen atoms in the ring or a 6-membered heteroaromatic ring with one to three nitrogen atoms in the ring, wherein the abovementioned 5- and 6-membered heteroaromatic rings may be optionally substituted by one to two alkyl groups or by a trifluoromethyl group,  
 and, unless otherwise stated, the abovementioned alkyl, alkylene and alkoxy moieties in each case contain 1 to 4 carbon atoms,  
 or a tautomer, stereoisomer or salt thereof.  
 
     
     
         3 . A trisubstituted pyrimidine of formula I according to  claim 2 , wherein 
 R a  denotes a hydrogen atom or a methyl group,    R b  denotes a phenyl group substituted by the groups R 1  to R 5 , while 
 R 1  denotes a hydrogen, fluorine, chlorine, bromine or iodine atom, 
 an alkyl, hydroxy or alkoxy group,  
 a C 3-6 -cycloalkyl or C 5-6 -cycloalkoxy group,  
 a C 2-4 -alkenyl, C 3-4 -alkenyloxy, C 2-4 -alkynyl or C 3-4 -alkynyloxy group, wherein the vinyl and ethynyl moieties cannot be linked with an oxygen atom,  
 a phenyl, phenyloxy, phenylalkyl, phenylalkoxy, alkylsulphenyl, alkylsulphinyl, alkylsulphonyl or alkylsulphonyloxy group,  
 a methyl or methoxy group substituted by 1 to 3 fluorine atoms,  
 an ethyl or ethoxy group substituted by 1 to 5 fluorine atoms,  
 a nitro, amino, alkylamino, dialkylamino or azido group,  
 a pyrrolidino, piperidino, morpholino, piperazino or 4-methyl-piperazino group,  
 an alkylcarbonylamino, N-alkyl-alkylcarbonylamino, alkylsulphonylamino or N-alkyl-alkylsulphonylamino group,  
 an alkylcarbonyl, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl or cyano group,  
 an aminosulphonyl, alkylaminosulphonyl or dialkylaminosulphonyl group,  
 an alkyl or alkoxy group substituted by R 9 , where 
 R 9  denotes a hydroxy, C 1-2 -alkoxy, amino, C 1-2 -alkylamino, di-(C 1-2 -alkyl)-amino, carboxy, C 1-2 -alkoxycarbonyl, aminocarbonyl, C 1-2 -alkylaminocarbonyl, di-(C 1-2 -alkyl)-aminocarbonyl or cyano group,  
 
 a 4- to 6-membered alkyleneimino group, a morpholino, piperazino or 4-methyl-piperazino group,  
 an alkylcarbonylamino, N-methyl-alkylcarbonylamino, alkylsulphonylamino, N-methyl-alkylsulphonylamino, alkoxycarbonylamino or N-methyl-alkoxycarbonylamino group,  
 
 R 2  denotes a hydrogen, fluorine, chlorine or bromine atom, a methyl, methoxy, trifluoromethyl or cyano group,  
 R 3  denotes a hydrogen, fluorine or chlorine atom, or  
 R 2  together with R 3 , if they are bound to adjacent carbon atoms, also denote a methylenedioxy group, an n-C 3-5 -alkylene group, wherein a methylene group may be replaced by an imino, N-methyl-imino or N-trifluoroacetyl-imino group, or a 1,3-butadiene-1,4-diylene group optionally substituted by a fluorine or chlorine atom, by a methyl, methoxy or trifluoromethyl group,  
 R 4  and R 5 , which may be identical or different, denote hydrogen or fluorine atoms,  
   R c  denotes a methyl, ethyl or propyl group which may be substituted by a hydroxy, alkoxy, dialkylamino group,    R d  denotes a hydrogen atom or a methyl group, and    R e  denotes a nitro, amino, alkylamino or dialkylamino group, 
 a pyrrolidino, piperidino, morpholino, piperazino, 4-methyl-piperazino, 2-oxo-pyrrolidino, 2-oxo-piperidino, 2,5-dioxo-pyrrolidino or 2,6-dioxo-piperidino group,  
 a formylamino, N-alkyl-formylamino, alkylcarbonylamino, N-alkyl-alkylcarbonylamino, C 3-6 -cycloalkylcarbonylamino, N-alkyl-C 3-6 -cycloalkylcarbonylamino, (C 3-6 -cycloalkyl)alkylcarbonylamino, N-alkyl-(C 3-6 -cycloalkyl)alkylcarbonylamino, phenylcarbonylamino, N-alkyl-phenylcarbonylamino, phenylalkylcarbonylamino, N-alkyl-phenylalkylcarbonylamino, alkoxycarbonylamino, N-alkyl-alkoxycarbonylamino, phenylalkoxycarbonylamino, N-alkyl-phenylalkoxycarbonylamino, phenyloxycarbonylamino, N-alkyl-phenyloxycarbonylamino, alkylsulphonylamino, N-alkyl-alkylsulphonylamino, di(methylsulphonyl)amino, C 3-6 -cycloalkylsulphonylamino, N-alkyl-C 3-6 -cycloalkylsulphonylamino, (C 3-6 -cycloalkyl)alkylsulphonylamino, N-alkyl-(C 3-6 -cycloalkyl)alkylsulphonylamino, phenylsulphonylamino, N-alkyl-phenylsulphonylamino, phenylalkylsulphonylamino, N-alkyl-phenylalkylsulphonylamino, cyanoamino, N-alkyl-cyanoamino, trifluoroacetylamino, N-alkyl-trifluoracetylamino, trifluoromethylsulphonylamino or N-alkyl-trifluoromethylsulphonylamino group, an alkylcarbonylamino or N-alkyl-alkylcarbonylamino group, while in each case the alkyl moiety of the alkylcarbonyl group is substituted by the group R 9 , where R 9  is as hereinbefore defined,  
 a pyrrolidinocarbonylamino, piperidinocarbonylamino, homopiperidinocarbonylamino, morpholinocarbonylamino, homomorpholinocarbonylamino, piperazinocarbonylamino, 4-alkylcarbonylpiperazinocarbonylamino, 4-alkylsulphonylpiperazinocarbonylamino or 4-alkyl-piperazinocarbonylamino group which in each case may be substituted at the carbonylamino moiety by an alkyl group,  
 a pyrrolidinothiocarbonylamino, piperidinothiocarbonylamino, morpholinothiocarbonylamino, piperazinothiocarbonylamino or 4-alkylpiperazinothiocarbonylamino group which may be substituted in each case at the thiocarbonylamino moiety by an alkyl group,  
 a R 7 NR 8 —CO—NR 6  or R 7 NR 8 —SO 2 —NR 6  group, wherein 
 R 6  denotes a hydrogen atom or an alkyl group,  
 R 7  and R 8  in each case independently of one another denote hydrogen atoms or alkyl groups optionally substituted by R 9 , or  
 R 6  and R 7  together denote an n-C 2-3 -alkyl group, and  
 R 8  denotes a hydrogen atom or an alkyl group optionally substituted by R 9 , while R 9  is as hereinbefore defined,  
 
 an imidazolidine-2,4-dion-1-yl or imidazolidine-2,4-dion-3-yl-group optionally substituted by an alkyl group,  
 a (R 14 NR 15 )—R 13 C═N-group wherein 
 R 13  denotes a hydrogen atom or an alkyl group,  
 R 14  and R 15  in each case independently of one another denote an alkyl group or  
 R 14  and R 15  together with the nitrogen atom between them denote a pyrrolidino, piperidino, morpholino, piperazino or 4-alkyl-piperazino group,  
 
 a (R 18 N═)CR 16 —R 17 N-group wherein 
 R 16  denotes an alkyl or trichloromethyl group,  
 R 17  denotes a hydrogen atom or an alkyl group and  
 R 18  denotes a hydrogen atom,  
 
   a dialkylphosphinylamino group optionally substituted at the nitrogen atom by an alkyl group, wherein the alkyl substituents may be identical or different, 
 a carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl or cyano group,  
 an aminosulphonyl, alkylaminosulphonyl or dialkylaminosulphonyl group,  
 a pyrrolidinocarbonyl, piperidinocarbonyl, morpholinocarbonyl, piperazinocarbonyl, 4-alkyl-piperazinocarbonyl, pyrrolidinosulphonyl, piperidinosulphonyl, morpholinosulphonyl, piperazinosulphonyl or 4-alkyl-piperazinosulphonyl group,  
 an optionally methyl group-substituted pyrrolyl, furyl, thienyl, imidazolyl, 1,2,4-triazolyl, tetrazolyl, oxazolyl, thiazolyl, pyridyl, pyrimidyl, 1,3,4-oxadiazolyl or 1,3,4-thiadiazolyl group,  
 an R 10 N═C(OR 11 ), R 10 N═C(NHR 11 ) or R 10 N═C(N-alkyl-NR 11 )-group, wherein 
 R 10  and R 11  together denote an n-C 2-3 -alkylene group optionally substituted by one or two methyl groups,  
 
 an amidino group optionally substituted by one to three alkyl groups or an amidino group substituted by a hydroxy, alkoxy, cyano, alkoxycarbonyl or phenylalkoxycarbonyl group, which may additionally be substituted at the nitrogen atoms by one or two methyl groups,  
 wherein, unless otherwise stated, the phenyl groups set forth above, either alone or as part of another group, may each independently be optionally substituted by a fluorine, chlorine or bromine atom or by a methyl, methoxy or trifluoromethyl group,  
 and, unless otherwise stated, the abovementioned alkyl, alkylene and alkoxy moieties each contain 1 to 4 carbon atoms,  
 or a tautomer, stereoisomer or salt thereof.  
   
     
     
         4 . A trisubstituted pyrimidine of formula I according to  claim 3 , wherein 
 R a  denotes a hydrogen atom or a methyl group,    R b  denotes a phenyl group substituted by the groups R 1  to R 5 , while 
 R 1  denotes a hydrogen, fluorine, chlorine, bromine or iodine atom, 
 a C 1-4 -alkyl, hydroxy or C 1-4 -alkoxy group,  
 an ethynyl, phenyl, phenyloxy or benzyloxy group,  
 a methylsulphenyl, methylsulphinyl or methylsulphonyl group,  
 a trifluoromethyl, trifluoromethoxy or 1,1,2,2-tetrafluoroethoxy group,  
 a nitro, dimethylamino or azido group,  
 a morpholino group,  
 an acetylamino or methylsulphonylamino group,  
 an acetyl, carboxy, C 1-2 -alkoxycarbonyl, aminocarbonyl or cyano group,  
 an aminosulphonyl group,  
 a C 1-2 -alkyl group which is substituted by a methoxy, amino, C 1-2 -alkylamino, di-(C 1-2 -alkyl)-amino, carboxy, C 1-2 -alkoxycarbonyl, pyrrolidino, piperidino, morpholino, piperazino, 4-methyl-piperazino, acetylamino, methyl-sulphonylamino or C 1-4 -alkoxycarbonylamino group,  
 an ethoxy group which is substituted in the 2 position by an amino, or C 1-4 -alkoxycarbonylamino group,  
 
 R 2  denotes a hydrogen, fluorine or chlorine atom or a methyl group,  
 R 3  denotes a hydrogen, fluorine or chlorine atom or  
 R 2  together with R 3 , if they are bound to adjacent carbon atoms, also denote an n-C 3-4 -alkylene group, an —CH 2 CH 2 NHCH 2 CH 2 -group optionally substituted at the nitrogen atom by a methyl or trifluoroacetyl group, or a 1,3-butadiene-1,4-diylene group,  
 R 4  and R 5  in each case independently of one another denote hydrogen or fluorine atoms,  
   R c  denotes a methyl, ethyl or propyl group, which may be terminally substituted by a hydroxy, methoxy or dimethylamino group,    R d  denotes a hydrogen atom or a methyl group,    R e  denotes a nitro or amino group, 
 a formylamino, C 1-4 -alkylcarbonylamino, cyclopropylcarbonylamino, phenylcarbonylamino, C 1-3 -alkoxycarbonylamino, benzyloxycarbonylamino, phenyloxycarbonylamino, C 1-4 -alkylsulphonylamino, N-methyl-methylsulphonylamino, di(methylsulphonyl)amino, phenylsulphonylamino, benzylsulphonylamino, trifluoroacetylamino, dimethylaminosulphonylamino, dimethylphosphinylamino, 1-iminoethylamino, 1-imino-2,2,2-trichloroethylamino or N′,N′-dimethyl-N-formamidino group,  
 a pyrrolidinocarbonylamino, piperidinocarbonylamino, homopiperidinocarbonylamino, morpholinocarbonylamino, piperazinocarbonylamino, 4-methylpiperazinocarbonylamino or 4-acetylpiperazinocarbonylamino group which may be substituted by a methyl group at the carbonylamino moiety in each case,  
 a morpholinothiocarbonylamino group,  
 a R 7 NR 8 —CO—NR 6 -group wherein 
 R 6  denotes a hydrogen atom or a methyl group, and  
 R 7  and R 8  in each case independently of one another represent hydrogen atoms or C 1-3 -alkyl groups, while the alkyl groups may be terminally substituted by a hydroxy, methoxy, dimethylamino or C 1-2 -alkoxycarbonyl group, or  
 R 6  and R 7  together denote a n-C 2-3 -alkylene group, and  
 R 8  denotes a hydrogen atom or a methyl group,  
 
   an imidazolidine-2,4-dion-3-yl-group,    a carboxy, C 1-2 -alkoxycarbonyl or cyano group,    an aminosulphonyl, methylaminosulphonyl or dimethylaminosulphonyl group,    a 1-pyrrolyl or 5-tetrazolyl group,    or a tautomer, stereoisomer or salt thereof.    
     
     
         5 . A trisubstituted pyrimidine of formula I according to  claim 4 , wherein 
 R a  and R d  each independently of one another represent a hydrogen atom or a methyl group,    R b  denotes a phenyl group substituted by one or two fluorine or chlorine atoms,    R c  a methyl, ethyl or propyl group, which may be terminally substituted by a dimethylamino group,    or a tautomer, stereoisomer or salt thereof.    
     
     
         6 . A trisubstituted pyrimidine of formula I according to  claim 5 , wherein 
 R e  denotes a nitro, acetylamino, trifluoroacetylamino, methylsulphonamino or amino group, or 
 a urea group of formula  
 R 7 NR 8 —CX—NR 6 ,  
  wherein 
 R 6  denotes a hydrogen atom or an alkyl group,  
 R 7  and R 8 , which may be identical or different, denotes hydrogen atoms or alkyl groups optionally substituted by hydroxy, methoxy or dimethylamino, or  
 R 6  and R 7  together denote an n-C 2-3 -alkylene group, and  
 R 8  denotes a hydrogen atom or an alkyl group optionally substituted by hydroxy, methoxy or dimethylamino, or  
 R 7  and R 8  taken together denote a C 4-8 -alkylenediyl group, while one or two non-adjacent CH 2  groups may be replaced by —O, —S or —NR 23 —, wherein 
 R 23  denotes a hydrogen atom, a C 1-3 -alkyl group or C 1-3 -alkanoyl group, and  
 
 X denotes O or S,  
 
   or a tautomer, stereoisomer or salt thereof.    
     
     
         7 . A compound selected from: 
 2-(4-chloroanilino)-4-methylamino-5-nitro-pyrimidine;    2-(3,4-dichloroanilino)-4-methylamino-5-amino-pyrimidine;    2-(3,4-dichloroanilino)-4-methylamino-5-methylsulphonamino-pyrimidine;    2-(3,4-dichloroanilino)-4-(3-dimethylaminopropyl)-amino-5-nitro-pyrimidine;    2-(3,4-dichloroanilino)-4-methylamino-5-acetamido-pyrimidine;    2-(3,4-dichloroanilino)-4-methylamino-5-(N-methyl-N-methylsulphonylamino)-pyrimidine;    2-(3,4-dichloroanilino)-4-methylamino-5-(2-oxo-imidazolidin-1-yl)-pyrimidine;    2-(3,4-dichloroanilino)-4-methylamino-5-(morpholin-1-ylcarbonylamino)-pyrimidine;    2-(3,4-dichloroanilino)-4-methylamino-5-(N 2 ,N 2 -dimethylureido)-pyrimidine;    2-[N-(3,4-dichlorophenyl)-N-methylamino]-4-methylamino-5-(2-oxo-imidazolidin-1-yl)-pyrimidine;    2-(3,4-dichloroanilino)-4-methylamino-5-(2-oxo-tetrahydropyrimidin-1-yl)-pyrimidine;    2-(3,4-dichloroanilino)-4-methylamino-5-ureido-pyrimidine;    2-(3,4-dichloroanilino)-4-dimethylamino-5-(morpholin-1-ylcarbonylamino)-pyrimidine;    2-(3,4-dichloroanilino)-4-ethylamino-5-(morpholin-1-ylcarbonylamino)-pyrimidine;    2-(3-chloroanilino)-4-methylamino-5-(morpholin-1-ylcarbonylamino)-pyrimidine;    2-(3,4-dichloroanilino)-4-methylamino-5-(pyrrolidin-1-ylcarbonylamino)-pyrimidine;    2-(3,4-dichloroanilino)-4-methylamino-5-(4-methylpiperazin-1-ylcarbonylamino)-pyrimidine;    2-(3,4-dichloroanilino)-4-methylamino-5-[N 2 ,N 2 -di-(2-methoxyethyl)-ureido]-pyrimidine;    2-(3,4-dichloroanilino)-4-methylamino-5-(azepanyl-1-carbonylamino)-pyrimidine;    2-(3,4-dichloroanilino)-4-methylamino-5-(N 2 ,N 2 -diethylureido)-pyrimidine;    2-(3,4-dichloroanilino)-4-methylamino-5-(piperazin-1-ylcarbonylamino)-pyrimidine;    2-(3,4-dichloroanilino)-4-methylamino-5-(4-acetylpiperazin-1-ylcarbonylamino)-pyrimidine;    2-(3,4-dichloroanilino)-4-methylamino-5-[N 2 -methyl-N 2 -(2-hydroxyethyl)-ureido]-pyrimidine;    2-(3,4-dichloroanilino)-4-methylamino-5-(morpholin-1-ylthiocarbonylamino)-pyrimidine;    2-(3,4-dichloroanilino)-4-methylamino-5-(2,2,2-trifluoroacetamido)-pyrimidine;    2-(3,4-dichloroanilino)-4-methylamino-5-[N 2 -methyl-N 2 -(2-dimethylaminoethyl)-ureido]-pyrimidine;    2-(3,4-dichloroanilino)-4-methylamino-5-[N 2 -methyl-N 2 -(3-dimethylaminopropyl)-ureido]-pyrimidine;    and the salts thereof.    
     
     
         8 . A physiologically acceptable salt of a compound of formula (I) according to  claim 1 .  
     
     
         9 . A process for preparing a trisubstituted pyrimidine of formula (I) according to  claim 1 , wherein: 
 a. a compound of formula                           wherein 
 R c  to R e  are defined as in  claim 1  and  
 Z 1  denotes a leaving group, is reacted with an amine of formula  
 H—(R a NR b )  (III)  
  wherein 
 R a  and R b  are defined as in  claim 1 , or  
 
   b. a compound of formula IV                           wherein 
 R a , R b  and R e  are defined as in  claim 1 , and  
 Z 2  denotes a leaving group, is reacted with an amine of formula  
 H—(R c NR d )  (V)  
  wherein 
 R c  and R d  are defined as in  claim 1 , or  
 
   c. to prepare a compound of formula I wherein R e  denotes an amino group, a compound of formula I wherein R e  denotes a nitro group is reduced and optionally a compound of formula I thus obtained is converted with a free amino or imino group, by reacting with an electrophil selected from among the isocyanates, isothiocyanates, carboxylic acids, sulphonic acids or their reactive derivatives, into a corresponding compound of formula I, and/or 
 a compound of formula I thus obtained which contains an amino, alkylamino or imino group is converted by alkylation or reductive alkylation into a corresponding alkyl compound of formula I; and/or  
 a compound of formula I thus obtained which contains an amino, alkylamino or imino group is converted by amidation with a corresponding acetimino derivative into a corresponding amidino compound of formula I; and/or  
 a compound of formula I thus obtained which contains a carboxy group is converted by esterification into a corresponding ester of formula I and/or  
 a compound of formula I thus obtained which contains a carboxy or ester group is converted by amidation into a corresponding amide of formula I and/or  
 if necessary any protecting group used during the reactions to protect reactive groups is cleaved; and/or  
 if desired a compound of formula I thus obtained is then resolved into the stereoisomers thereof; and/or  
 a compound of formula I thus obtained is converted into the salts thereof, particularly for pharmaceutical use into the physiologically acceptable salts thereof with an inorganic or organic acid or base.  
   
     
     
         10 . A pharmaceutical composition, comprising one or more compounds according to  claim 1 .  
     
     
         11 . A method of treating or preventing a disease that is treatable or preventable by the inhibition of amyloid-β-peptide in a patient, comprising adminstering to a patient in need thereof a therapeutically effective amount of a compound of formula (I) according to  claim 1 .  
     
     
         12 . A method according to  claim 11 , wherein the compound of formula (I) inhibits the formation of amyloid-β-peptide and/or inhibits the release of amyloid-β-peptide from cells.  
     
     
         13 . A method of treating or preventing Alzheimer's disease in a patient, comprising administering to a patient in need thereof a therapeutically effective amount of a compound of formula (I) according to  claim 1.