Adrian Waldner

Comparison of rigid and flexible backbones in antisense oligonucleotides

Abstract Stepwise restriction of free rotation, as well as introduction of positive changes in the internucleosidic linkage are factors which can positively influence the thermal melting behaviour of the corresponding duplexes formed between modified DNA and their RNA complement. By correct positioning of the rigidity within backbone, it is possible to achieve even higher binding affinity (Tms) than with natural oligodeoxyribonucleotides (ODNs).

Comparison of two amides as backbone replacement of the phosphodiester linkage in oligodeoxynucleotides

Abstract The two isomeric amide modifications 1 and 2 show similar effects on the melting temperature of RNA/DNA duplexes, when they replace the natural phosphodiester linkage in the DNA strand. The synthesis of the amide dimer 1 is presented.

Synthesis and application of a highly efficient, homochiral dienophile

Abstract The synthesis and application of a highly efficient, homochiral dienophile is described. Cycloaddition of 2-((S)-1-phenylethyl)-1,2- thiazolin-3-on-(S)-1-oxide 1a with a 1-azadiene and cyclopentadiene affords the corresponding cycloadducts in good yield and excellent diastereoselectivity.

Competing radical translocation reactions of tertiary N-(2-bromobenzyl)- and N-(8-bromonaphthyl)-acetamides

Abstract The radical translocation reactions in N,N-disubstituted acetamides 10a, 14a–d and trifluoroacetamides 10b, 14e–f have been studied by deuteration experiments with n-Bu 3 SnD. The intramolecular hydrogen atom transfer from the N-alkyl side chain to the aryl radical takes place through competing 6-, 7-, 8-membered ring transition states.

Replacement of the phosphodiester linkage in oligonucleotides : comparison of two structural amide isomers

Abstract The two structural amide isomers 2 and 3 as backbone replacement in oligonucleotides lead to very similar results for the binding affinities (Tm) of the duplexes formed with their complementary RNA strands.

Synthesis of Oligodeoxyribonucleotides containing dimers with carbamate moieties as replacement of the natural phosphodiester linkage

Abstract The synthesis of thymidine dimers containing both possible regioisomeric carbamate moieties in place of the natural phosphodiester backbone is described. These dimers were incorporated in oligodeoxyribonucleotides and melting temperatures (T m ) of the DNA/RNA and DNA/DNA duplexes are reported. In addition the nuclease resistance of these single strands were determined.

Hydrophobic effects in duplexes with modified oligonucleotide backbones and RNA

Abstract The incorporation of hydrophobic substituents on the amide functionality of modified oligonucleotides drastically influences the thermal stability of the corresponding duplexes with the RNA complement.

Synthese heterocyclischer α-oxo-essigsaeureester mit einem neuen acylanionaequivalent

Abstract The synthesis of new heterocyclic α-oxo-acetic acid esters with the novel and easily available acylanion equivalent 5 is described.

A Short Synthesis of Fusaric Acid and Analogues

Abstract Fusaric acid (5-n-butyl-pyridine-2-carboxylic acid) and other substituted picolinic acid derivatives are synthesized in two steps from readily available α,β-unsaturated hydrazones and 2-chloroacrylonitrile in high yield.