25979-51-5 NSC73853 Urea, 1,1'-(2-chloro-p-phenylene)bis[3-[p-(1,4,5,6-tetrahydro-2-pyrimidinyl)phenyl]-, dihydrochloride Urea, N,N''-(2-chloro-1,4-phenylene)bis[N'-(1,4,5,6-tetrahydro-2-pyrimidinyl)phenyl]-, dihydrochloride