Synthesis of highly efficient pH-sensitive DNA cleaving aminomethyl N-substituted cyclic enediyne and its L-lysine conjugate

Two 10-membered benzo-fused N-substituted cyclic enediynes, one an amino methyl and the other, a C-lysine conjugated derivative 2 and 3, respectively were synthesized (as a 1.2:1 mixture of regioisomers) and their DNA-cleavage efficiency studied. Both the compounds showed much better DNA-cleavage profile than that of the parent unsubstituted enediyne 1. The lysine conjugate 3 showed an efficient pH dependent cleavage to the extent of ∼50% of linear DNA formation under ambient conditions.