Novel 2'-deoxyuridine analogues carrying aminoalkyl linkers at the 1'-position of the sugar residues were synthesized and incorporated into oligonucleotides, then intercalating groups such as an anthraquinone derivative and a pyrene derivative were attached to the amino groups. Duplexes consisting of the oligonucleotides carrying the linker groups and a complementary ribonucleotide were more stable than an unmodified parent duplex, but the duplexes consisting of the oligonucleotides and a complementary deoxyribonucleotide were less stable. The oligonucleotides carrying the linker groups were more resistant to nuclease P1 and venom phosphodiesterase than an unmodified oligonucleotide. Furthermore, a duplex formed by the oligonucleotide analogue and the complementary ribonucleotide was a substrate for ribonuclease H.

We have previously developed a novel method for the stereocontrolled synthesis of β‐manno‐glycoside. Starting from 2‐O‐PMB (p‐methoxybenzyl)‐protected mannosyl donor 1, conversion into the mixed acetal 3 under oxidative conditions followed by the activation of the anomeric position affords β‐manno‐glycoside as a single stereoisomer. Although the utility of this method has been further demonstrated in the synthesis of the core structure of Asn‐linked glycan chains, there remained uncertainty with respect to the stereochemistry of the mixed acetal. In order to make a stereochemical assignment of this intermediate, diastereomeric acetals 14a, 15a and 14b, 15b were prepared from 9 + 10/7 and 11 + 12/13, respectively. Investigations by means of NMR and a computational approach using DADAS 90 for quantifying steric hindrance, resulted in the conclusion that 14a/15a derived from 2‐O‐PMB‐protected 9 has an (S) configuration and 14b/15b derived from 2‐O‐unprotected 11 has an (R) configuration. Based on the characteristic 1H‐NMR patterns inherent to the (S) isomers, 4,6‐O‐benzylidene‐protected 30–35, derived from thiomannosides 5, 23, 24, 26, 27, were also revealed to have the (S) configuration.

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