The synthesis and polymerization of 2-cyanoethyl N-vinylcarbamate (3b) and of the corresponding 2-trimethylsilylethyl isomer 3c are reported. The homopolymers 4b and 4c, derived from 3b and 3c, could be deblocked under mild conditions (ethanolamine for 4b and trifluoroacetic acid or tetraethylammonium fluoride for 4c) with essentially 100% unmasking of the amino function. Treatment of such unmasked amino groups in a copolymer derived from N-vinyl-2-pyrrolidone and 3b with 4-{4-[bis(2-chloroethyl)amino]phenyl}butyryl chloride (13) (chlorambucil chloride) gave the corresponding amide, a potential antitumor agent. Kinetic studies showed that fluoride ion cleavage of poly(2-trimethylsilylethyl …