3-(2-Benzylthio-3,4-dihydro-4-oxo-6-pyrimidinyl)-1- (2-chloroethyl)-1-nitrosourea NSC609973 Urea, N-(2-chloroethyl)- N'-[1,6-dihydro-2-[(phenylmethyl)thio]-6-oxo-4- pyrimidinyl]-N-nitroso-