Synthesis of achiral α,α-disubstituted β-alanines, and their use in construction of libraries of β-peptide conjugates of N-2-alkyl-1,2,3,4-tetrahydroisoquinolines on a solid support

Oligonucleotides bearing pentaerythritol-derived mass tags

Five different di-O-alkylated pentaerythritol phosphoramidite building blocks (2a–e) were synthesized and introduced into oligonucleotides to obtain mass-tagged probes (6a–f) useful in RNA transcription profiling. These non-nucleosidic mass tags allow categorization of oligonucleotide probes having identical nucleoside content and, hence, identification of the probe hybridized to RNA by mass spectrometry analysis. Hybridization properties of the oligonucleotide conjugates were elucidated by melting temperature measurements.

Regioselective copper-catalyzed amination of bromobenzoic acids using aliphatic and aromatic amines

A chemo- and regioselective copper-catalyzed cross-coupling procedure for amination of 2-bromobenzoic acids is described. The method eliminates the need for acid protection and produces N-aryl and N-alkyl anthranilic acid derivatives in up to 99% yield. N-(1-Pyrene)anthranilic acid has been employed in metal ion-selective fluorosensing. Titration experiments showed that this pyrene-derived amino acid forms an equimolar complex with Hg(II) in water resulting in selective fluorescence quenching even in the presence of other metal ions such as Zn(II) and Cd(II).