3-(2-(Isothioureido)ethyl thio)propyl isothiourea dihydrochloride 64058-47-5 Pseudourea, 2,2'-thioethylenetrimethylenebis(thio-, dihydrochloride Pseudourea, 3-(2-(isothioureido)ethylthio)propyl-2-thio, dihydrochloride USAF EL-71