3-(2-Benzylthio-3,4-dihydro-4-oxo-6-pyrimidinyl)- 1-methyl-1-nitrosourea NSC609971 Urea, N-[1,6-dihydro-6-oxo-2- [(phenylmethyl)thio]-4-pyrimidinyl]-N'-methyl-N'-nitroso-