Disclosed are compounds of the general formula wherein R 1 represents heterocyclyl; R 2 represents hydrogen, unsubstituted lower alkyl, lower alkoxy, halo, hydroxy or cyano; R 3 represents hydrogen, unsubstituted lower alkyl, lower alkoxy, halo, or cyano; R 4 represents hydrogen, lower alkyl, lower cycloalkyl, aryl, or heterocyclyl; R 5 represents hydrogen, unsubstituted lower alkyl, lower alkoxy, halo, or cyano; R 6 represents hydrogen, unsubstituted lower alkyl, lower alkoxy, halo, or cyano; R 7 represents hydrogen, or unsubstituted lower alkyl; R 8 represents hydrogen, or unsubstituted lower alkyl; or R 4 and R 8 together with the nitrogen atom to which they are attached represent heterocyclyl; and pharmaceutically acceptable salts thereof. The disclosed oxamide derivatives are inhibitors of the enzyme inosine monophosphate dehydrogenase (IMPDH). They can be used as medicaments, especially for treating immune mediated conditions or diseases, viral diseases, bacterial diseases, parasitic diseases, inflammation, inflammatory diseases, hyperproliferative vascular diseases, tumours, and cancer. They can be used alone, or in combination with other therapeutically active agents, for example, an immunosuppressant, a chemotherapeutic agent, an anti-viral agent, an antibiotic, an antiparasitic agent, an anti-inflammatory agent, an anti-fungal agent and/or an anti-vascular hyperproliferation agent.