Xanthine derivatives, the preparation thereof and their use as pharmaceutical compositions

Abstract From the Canadian patent

The present invention relates to substituted xanthines of general formula (see formula I), wherein R1 is, for example H, optionally substituted alkyl, alkenyl alkynyl, an aryl , or a heterocylic group; R 2 is for example, H, an optionally substituted alkyl or , alkenyl, alkynyl cycloalkyl an aryl or a heterocyclic group; R3 is for , example, optionally substituted alkyl optionally substituted alkenyl, alkynyl or , aryl; and R4 is, a substituted heterocyclic group; the tautomers and the stereoisomers thereof mixtures thereof, the prodrugs and the salts thereof which have valuable pharmacological properties, particularly an inhibiting effect on the activity of the , enzyme …