Synthesis of Modified Nucleic Acid Derivatives

A controlled pore glass support (CPG) derivatized with 2′-O-TBDMS-G, 2′-O-methyl-G, deoxycytosine (dC) or deoxythymidine (dT), 5′,N-protected 2′-O-methylribo- (A, C, G or U), 2′-O-TBDMS-ribo (A, C, G or U) and deoxyribo (dA, dC, dG or dT,) phosphoramidites, 1-O-dimethoxytrityl-hexyl-disulfide,1′-[(2-cyanoethyl)-(N,N-diisopropyl)]-phosphoramidite (Thiol-Modifier C6 S–S) were purchased from Glen Research Inc (Sterling, VA, USA). (Pyrene-1-yl-methyl)amine hydrochloride, N,N-diisopropylethylamine (DIPEA), trileucine, α-tocopherol, propargylamine, hexamethylenediamine, were purchased from Sigma-Aldrich (St. Louis, MO, USA), N,N′-disuccinimidyl carbonate (DSC), cholesterol chloroformate, folic acid, oleylamine were purchased from Acros Organics (Geel, Belgium), Cy3-azide, 10 mM Cu(II)-TBTA Stock in 55% DMSO, ascorbic acid were purchased from Lumiprobe (Russia), dodecamethylenediamine was from Fluka (St. Louis, MO, USA), 12-amino-1-dodecanol was from TCI Chemicals (India), and sodium dodecaborate Na₂[B₁₂H₁₂] was from AviaBor (Dzerzhinsk, Russia). N-(2-hydroxyethyl)phenazinium chloride was obtained in ICBFM SB RAS as described in previous work [44 (link)]. All solvents (THF, DMSO, CH₃CN (various vendors)) were dried by 3 Å molecular sieves or by distillation and stored over CaH₂. Kieselgel F254 thin-layer chromatography plates were purchased from Merck (Kenilworth, NJ, USA).