p. 300,301
(1973)1,3-Dimethyl-5-(4-nitro-phenylazo)-6-{N'-[1-phenyl-meth-(Z)-ylidene]-hydrazino}-1H-pyrimidine-2,4-dione
1,3-Dimethyl-5-phenylazo-6-{N'-[1-phenyl-meth-(Z)-ylidene]-hydrazino}-1H-pyrimidine-2,4-dione
1,7-Dihydro-5,7-dimethyl-3-phenyl-4H-pyrazolo<3,4-d>pyrimidin-4,6(5H)-dion
4,6-dimethyl-4H-[1,2,3]thiadiazolo[4,5-d]pyrimidine-5,7-dione
1,3-dimethyl-8-phenylxanthine