| abstract |
[3H]-Imidazo[5,1-d]-1,2,3,5-tetrazin-4-one derivatives of the formula: <IMAGE> in which R<1> denotes hydrogen or an alkyl, alkenyl or alkynyl group having up to 6 carbon atoms, each such group being unsubstituted or substituted by one to three substituents selected from halogen atoms, alkoxy, alkylthio, alkylsulphinyl and alkylsulphonyl groups having up to 4 carbon atoms and optionally substituted phenyl groups, or R<1> denotes a cycloalkyl group having 3 to 8 carbon atoms, and R<2> denotes a carbamoyl group, optionally N-substituted by one or two groups selected from alkyl and alkenyl groups having up to 4 carbon atoms and cycloalkyl groups having 3 to 8 carbon atoms, are novel therapeutically useful compounds having antineoplastic and immunomodulatory activity. |