77749-76-9 8-Benzylthio-4-(1-oxidothiomorpholino)-2-piperazino-pyrimido(5,4-d)pyrimidine Pyrimido(5,4-d)pyrimidine, 8-((phenylmethyl)thio)-2-(1-piperazinyl)-4-(4-thiomorpholinyl)-, S-oxide