Formula (I) compounds ##STR00001## are described where the groups are as identified in the text, and their use as medicines, particularly as anti-diabetes, serum glucose-lowering and anti-obesity agents. They are useful for the prophylaxis and treatment of diabetes, particularly type 2 diabetes, and its complications, syndrome X, the various forms of insulin resistance, and hyperlipidaemias, as well as for the treatment of obesity.