The present invention provides compounds or formula (1)
R.sub.1--HN--CH.sub.2--CF.sub.2--(CH.sub.2).sub.l--CR.sub.3R.sub.4--CO--R-
.sub.2, wherein: l is 0, 1 or 2, R.sub.1 is a labile amino protecting
group, R.sub.2 is hydroxy group or the residue or an activated ester or
halogen atom; R.sub.3 and R.sub.4 are independently hydrogen atom or
C.sub.1-C.sub.4 alkyl chain. There are also provided their preparation
and the water-soluble conjugates based on these linkers, endowed with
selective anticancer activity.
