The invention relates to a novel group of compounds of Formula (I) or a salt thereof: wherein R.sup.1, A and HET-1 are as described in the specification, which may be useful in the treatment or prevention of a disease or medical condition mediated through glucokinase (GLK) such as type 2 diabetes. The invention also relates to pharmaceutical compositions comprising said compounds, methods of treatment of diseases mediated by GLK using said compounds and methods for preparing compounds of Formula (I).