Pyrimido(5,4-d)pyrimidin-4-amine, N-methyl-N-(phenylmethyl)-6-(1-piperazinyl)-8-(4-thiomorpholinyl)-, S-oxide

4-{8-[Benzyl(methyl)amino]-2-(piperazin-1-yl)pyrimido[5,4-d]pyrimidin-4-yl}-1lambda~4~-thiomorpholin-1-one