DNA-Templated N(Me)-Alkoxyamine Glycosylation

Immobilized Carbohydrates for Preparation of 3'-Glycoconjugated Oligonucleotides

A detailed protocol for preparation 3'-glycoconjugated oligonucleotides is described based on one-pot immobilization of 4,4'-dimethoxytrityl-protected carbohydrates to a solid support followed by on-support peracetylation and automated oligonucleotide assembly. Compared to an appropriate building block approach and post-synthetic manipulation of oligonucleotides, this protocol may simplify the synthesis scheme and increase overall yield of the conjugates. Furthermore, the immobilization to a solid support typically increases the stability of reactants, enabling prolonged storage, and makes subsequent processing convenient. Automated assembly on these carbohydrate-modified supports using conventional phosphoramidite chemistry produces 3'-glycoconjugated oligonucleotides in relatively high yield and purity. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Synthesis of 1-O-tert-butyldimethylsilyl-6-O-(4,4'-dimethoxytrityl)-β-D-glucose Basic Protocol 2: Synthesis of 6-O-dimethoxytrityl-2,3,1',3',4',6'-hexa-O-benzoylsucrose Basic Protocol 3: Synthesis of 6″-O-dimethoxytrityl-N-trifluoroacetyl-protected aminoglycosides Basic Protocol 4: Synthesis of 3-O-dimethoxytrityl-propyl β-D-galactopyranoside Basic Protocol 5: Synthesis of trivalent N-acetyl galactosamine cluster Basic Protocol 6: Synthesis of carbohydrate monosuccinates and their immobilization to a solid support Basic Protocol 7: Oligonucleotide synthesis using immobilized carbohydrates.

Conjugation of Oligonucleotides to Peptide Aldehydes via a pH-Responsive N-Methoxyoxazolidine Linker

The formation of N-methoxyoxazolidines in the preparation of oligonucleotide-peptide conjugates was evaluated. The reaction occurred between unprotected 2'-N-(methoxy)amino-modified oligonucleotides and peptide aldehydes in reasonable yields when isolated. The reaction is reversible under slightly acidic conditions, and it is pH-responsive. The rate and the equilibrium constant may be varied with structurally different aldehydes, allowing an optimization of the ligation and cleavage rate of the resultant conjugates. Therefore, this concept can be considered a cleavable linker.