Khalil I. Shaikh

PROPYNYL GROUPS IN DUPLEX, HAIRPIN AND TRIPLEX DNA: 7-DEAZAPURINES AND 9-DEAZAPURINES

Oligonucleotides containing 7-deazapurines or 9-deazapurines with propynyl groups at the 7- or 9-position were prepared. The stabilizing effect of the propynyl group was studied on DNA duplexes, hairpins and triplexes.

Synthesis and properties of halogenated 7-deaza-2'-deoxyxanthosine and protected derivatives for oligonucleotide synthesis.

Abstract The 7-bromo- (4a) and 7-iodo- (4b) derivatives of 7-deaza-2′-deoxyxanthosine (5) are prepared. Furthermore, the building blocks 6–8 of 7-deaza-2′-deoxyxanthosine (5) are synthesized and tested for their usage in oligonucleotide synthesis.

7-Deaza-2′-Deoxyxanthosine: Nucleobase Protection and Base Pairing of Oligonucleotides

Oligonucleotides containing 7-deaza-2′-deoxyxanthosine (1) and 2′-deoxyxanthosine (2) were prepared. The 2-(4-nitrophenyl)ethyl group is applicable for 7-deazaxanthine protection that is removed with DBU by β-elimination, while the deprotection of the allyl residue with Pd (0) catalyst failed. Contrarily, the allyl group was found to be an excellent protecting group for 2′-deoxyxanthosine (2). The base pairing of nucleosides 1 and 2 with the four canonical DNA constituents as well as with 3 within the 12-mer duplexes is studied.