| abstract |
The invention relates to compounds of formula (I). ##STR1## wherein R 1 represents a hydrogen atom or a C 1-10 alkyl, C 3-7 cycloalkyl, C 3-6 alkenyl, C 3-7 cycloalkyl-(C 1-4 ) alkyl, C 3-10 alkynyl, phenyl or phenyl-C 1-3 alkyl group, and one of the groups represented by R 2 , R 3 and R 4 is a hydrogen atom or a C 1-6 alkyl, C 3-7 cycloalkyl, C 2-6 alkenyl or phenyl-(C 1-3 ) alkyl group and each of the other two groups, which may be the same or different, represents a hydrogen atom or a C 1-6 alkyl group; and physiologically acceptable salts and solvates, e.g. hydrates thereof. n The compounds are potent selective antagonists at "neuronal" 5-hydroxytryptamine receptors and are useful in the treatment of migraine and psychotic disorders such as schizophrenia. |