Synthesis and physicochemical properties of decanucleotides containing (3′→ 5′)-O-CH2-O-linkages at predetermined positions

Synthesis of the modified decadeoxynucleotides 16–20 having the sequence d(G1pC2pG)3pT4x1T5x2T6x3T7pG8pC9pG10) and containing one (x2 = CH2, x1 = x3 = p, i.e., 16), two (x1 = x3 = CH2, x2 = p, i.e., 17, x2 = x3 = CH2, x1 = p, i.e., 18 and x1 = x2 = CH2, x3 = p. i.e., 19) or three (x1 = x2 = x3 = CH2, i.e., 20) -O-CH2-O- linkages could be accomplished using the respective mono-, di- or tri(-O-CH2-O) 3′-O-phosphoramidites 6, 10 and 14 as the incoming synthons. Hybridization of 16–20 with their native complementary strand afforded stable duplexes, which were studied by 1D- and 2D-1H-NMR and UV-hyperchromicity techniques.