Andreas Kehne

Synthesis and Application of Isosteric Purine 2′-Deoxyribofuranosides

Abstract The diastereoselective synthesis of several pyrrolo[2,3-d]- and pyrazolo[3,4-d]pyrimidine 2′-deoxy-ribofuranosides employing l-chloro-2-deoxy-3,5-di-0-(p-tolu-oyl)-a-D-erythropentofuranose and the nucleobase anion, generated by liquid-liquid or solid-liquid phase-transfer catalysis, is described. Appropriately protected phosphoramidites of 8-aza-7-deaza-2′-deoxyadenosine and 2′-deoxytubercidin were prepared and employed in solid-phase synthesis of palindromic DNA-fragments. The replacement of dA residues by deoxytubercidin within the Eco RI recognition site d(GAATTC) of the dodecamer d(GTAGAATTCTAC) gave evidence for purine N-7 binding to the endodeoxyribonuclease. The interpretation of similar experiments carried out on d(CGCGAATTCGCG) was obscured because of hairpin formation.

Phosphoramidites of [180] Chiral (Rp)- and (Sp)-Configurated Dimer-Blocks and their Use in Automated Oligonucleotide Synthesis

Abstract The N,N-diisopropylphosphoramidites 1 and 2 of appropriately protected chiral diastereoisomers of d(T-[P-180]-A) (6a and 6o, resp.) have been synthesized. They were employed in solid-phase synthesis to yield the octamers d(GAGT-(Rp)-[P180]-ACTC) and d(GAGT-(Sp)-[P180]-ACTC).