2-substituted 1,2-benzoisothiazole derivatives and their use as serotonin antagonists (5-ht1a, 5-ht1b and 5-ht1d)

2-Substituted 1,2-benzisothiazole derivatives of formula (I) and their enantiomers, diastereomers, tautomers and acid salts are disclosed. R1 and R2 are independently C1-6 alkyl; R3 and R4 are independently H, C1-6 alkyl, OH, C1-6 alkoxy, F, Cl, Br, I, CF3, NR5R6, CO2R7, NO2, CN, pyrrolo, or phenyl-(C1-4 alkyl), which may itself be ring-substituted by F, Cl, Br, I, C1-4 alkyl, C1-4 alkoxy, CF3, OH, NH2, CN or NO2; R5 and R6 are independently H, C1-6 alkyl, benzoyl, CO2-tert.-butyl, (C1-4 alkyl)carbonyl or together form a 5- or 6-membered ring, which may contain a second N atom (e.g. piperazinyl); R7 is H or C1-6 alkyl; A is C1-10 alkylene or C2-10 alkylene containing one or more Z groups; Z is O, S, NR7, cyclopropyl, CHOH, or a double or triple bond; B is 4-piperidine, 4-(1,2,3,6-tetrahydropyridine), 4-piperazine or one of these rings N-bound to A via a methylene group; Ar is phenyl (optionally substituted by C1-6 alkyl, C1-6 alkoxy, OH, F, Cl, Br, I, CF3, NR5R6, CO2R7, CN or phenyl), tetralinyl, indanyl, other condensed aromatic moieties e.g. naphthalinyl (optionally substituted by C1-4 alkyl or C1-4 alkoxy), anthracenyl, or a 5- or 6-membered aromatic heterocycle with 1 or 2 O or N heteroatoms, which can be fused with other aromatic groups.