Substituted dihydroquinazolines

A compound of the formula

• in which
• Ar represents aryl which may be substituted by 1 to 3 substituents, where the substituents are selected independently of one another from the group consisting of alkyl, alkoxy, formyl, carboxyl, alkylcarbonyl, alkoxycarbonyl, trifluoromethyl, halogen, cyano, hydroxyl, amino, alkylamino, aminocarbonyl and nitro,
• where alkyl may be substituted by 1 to 3 substituents, where the substituents are selected independently of one another from the group consisting of halogen, amino, alkylamino, hydroxyl and aryl,
• or two of the substituents on the aryl radical together with the carbon atoms to which they are attached form a 1,3-dioxolane, a cyclopentane ring or a cyclohexane ring, and any third substituent present is selected independently from the group mentioned,
• R1 represents hydrogen, amino, alkyl, alkoxy, alkylamino, alkylthio, cyano, halogen, nitro or trifluoromethyl,
• R2 represents hydrogen, alkyl, alkoxy, alkylthio, cyano, halogen, nitro or trifluoro-methyl,
• R3 represents amino, alkyl, alkoxy, alkylamino, alkylthio, cyano, halogen, nitro, trifluoromethyl, alkylsulphonyl or alkylaminosulphonyl
• or
• one of the radicals R1, R2 and R3 represents hydrogen, alkyl, alkoxy, cyano, halogen, nitro or trifluoromethyl and the other two together with the carbon atoms to which they are attached form a 1,3-dioxolane, a cyclopentane ring or a cyclohexane ring,
• R4 represents hydrogen or alkyl,
• R5 represents hydrogen or alkyl
• or
• the radicals R4 and R5 are attached to carbon atoms directly opposing each other in the piperazine ring and form a methylene bridge which is optionally substituted by 1 or 2 methyl groups,
• R6 represents alkyl, alkoxy, alkylthio, formyl, carboxyl, aminocarbonyl, alkylcarbonyl, alkoxycarbonyl, trifluoromethyl, halogen, cyano, hydroxyl or nitro,
• R7 represents hydrogen, alkyl, alkoxy, alkylthio, formyl, carboxyl, alkylcarbonyl, alkoxycarbonyl, trifluoromethyl, halogen, cyano, hydroxyl or nitro
• and
• R8 represents hydrogen, alkyl, alkoxy, alkylthio, formyl, carboxyl, alkylcarbonyl, alkoxycarbonyl, trifluoromethyl, halogen, cyano, hydroxyl or nitro,
• or a salt, solvate, or solvate of a salt thereof.