A class of chemical compounds comprising a pyrrolo[2,3-b]-pyridine moiety and a carboxamido-substituted heterocyclic moiety, linked via the 3-position of the pyrrolo[2,3-b]pyridine moiety by a methylene group, are ligands for dopamine receptor subtypes within the body and are therefore useful in the treatment and/or prevention of disorders of the dopamine system, in particular schizophrenia. The compounds have the formula:- <IMAGE> wherein the broken line represents an optional chemical bond; R<2> is a defined organic radical linked through carbon and A and the remaining R groups are hydrogen atoms or various defined groups.
Pyrrolo-pyridine derivatives