Tetrazine derivatives

摘要

[ 3H]-Imidazo[ 5,1-d] -1,2,3,5-tetrazin-4-one derivatives of the formula: <IMAGE> wherein R1 represents hydrogen, or an alkyl, alkenyl or alkynyl group containing up to 6 carbon atoms, each such group being unsubstituted or substituted by from one to three substituents selected from halogen atoms, alkoxy, alkylthio, alkylsulphinyl and alkylsulphonyl groups containing up to 4 carbon atoms, and optionally substituted phenyl groups, or R1 represents a cycloalkyl group containing from 3 to 8 carbon atoms, and R2 represents a carbamoyl group optionally N-substituted by one or two groups selected ftom alkyl and alkenyl groups containing up to 4 carbon atoms, and cycloalkyl groups containing 3 to 8 carbon atoms, are new therapeutically useful compounds possessing antineoplastic and immunomodulatory activity.