The present invention provides lysine based compounds of the formula; ##STR00001## and when the compound of formula I comprises an amino group, pharmaceutically acceptable ammonium salts thereof, wherein R.sub.1 may be, for example, (HO).sub.2P(O)--, (NaO).sub.2P(O)--, alkyl-CO-- or cycloalkyl-CO--, wherein X may be, for example, F, Cl, and Br, and wherein R.sub.2 and R.sub.3 are as defined herein.