25775-33-1 NSC71199 Urea, 1,1'-p-phenylenebis[3-[p-(3-methylguanidino)phenyl]-, dihydrochloride Urea, N,N''-1,4-phenylenebis[N'-[4-[[imino(methylamino)methyl]amino]phenyl]-, dihydrochloride