[Modification of nucleic acids in stabilized complementary complexes. II. Effectiveness and direction of alkylation of dodecadeoxyribonucleotide d(pA-A-C-C-T-G-T-T-T-G-G-C) with 4-(N-2-chloroethyl-N-methylamino)benzylidene derivative of the complementary heptanucleotide d(pC-C-A-A-A-C)-A containing a N-(2-hydroxyethyl)phenazinium residue at the 5'-end].

Modification of dodecadeoxyribonucleotide d(pA-A-C-C-T-G-T-T-T-G-G-C) (I) with a heptanucleotide 4-(N-2-chloroethyl-N-methylamino)benzylidene (RCI) derivative d(pC-C-A-A-A-C) ARCI (II) and with similar reagent (III) bearing an additional 5'-terminal N-(2-hydroxyethyl)phenazinium residue (Phn) has been unvestigated. Both reagents (II) and (III) alkylated dodecanucleotide (I) mainly at the 5'-terminal phosphate, Phn residue not affecting specificity of the alkylation. Stabilization of the complementary complex target oligonucleotide-oligonucleotide derivative by the Phn group resulted in substantial increase of efficiency and rate of the intracomplex alkylation of the dodecanucleotide.