##STR00001## A compound of formula (I) wherein R.sub.1 is a straight chain, branched or cyclic aliphatic, aromatic or heterocyclyl group comprising at least 8 carbon atoms, e.g. 8 to 22, R.sub.2 is a straight chain, branched or cyclic aliphatic, aromatic or heterocyclic group comprising from 1 to 12 carbon atoms, and ring A is heterocycyl, fused with the phenyl ring to which ring A is attached comprising 5 or 6 ring members, and 1 to 4 heteroatoms selected from N, S, O; wherein certain compounds are excluded by proviso and the use of such compounds without proviso as pharmaceuticals in disorders which are mediated by ceramide kinase.