Biotin and fluorescein labeling of biomolecules by active esters of 1-phenylpyrazolin-5-ones

Palladium(0)-Catalyzed Modification of Oligonucleotides during Automated Solid-Phase Synthesis

“…Oligonucleotides modified with functional groups have diverse and important research and clinical applications, including primers for DNA sequencing, hybridization probes for detecting DNA, antisense and antigene oligonucleotides for therapy, and spectroscopic probes for DNA structure and function studies. − Synthetic strategies toward these complex oligonucleotides focus primarily on either synthesizing the labeled phosphoramidite for subsequent incorporation into the nucleic acid strand or modifying the synthesized nucleic acid single strand after solid-phase synthesis . The major hurdles with the first procedure are the multiple synthetic and purification steps to the desired phosphoramidite, which is moisture-sensitive and often possesses limited solubility in common solvents, followed by the low coupling yield on the DNA synthesizer and chromatographic purifications of the oligonucleotide derivative.…”

Efficient Solution Phase Synthesis of Oligonucleotide Conjugates Using Protected Biopolymers Containing 3‘-Terminal Alkyl Amines

“…Modified oligonucleotides are finding increasing application as therapeutic candidates and as mechanistic and diagnostic probes. − In addition, as the goal of sequencing the human genome approaches reality, the growing need for determining gene function promises to provide further uses for modified oligonucleotides. One general family of modified oligonucleotides that are valuable for the above applications are those biopolymers that are covalently bonded to a variety of molecules including fluorescent tags, intercalators, hydrophobic species, enzyme cofactors, and peptides.…”

Introducing Structural Diversity in Oligonucleotides via Photolabile, Convertible C5-Substituted Nucleotides

“…The strategy presented below capitalizes on developments for selectively unmasking a single functional group within a protected oligonucleotide, and for conjugating oligonucleotides to small organic molecules in solution or while anchored to a solid-phase support. − Oligonucleotides containing 3‘-alkylamines or 3‘-alkyl carboxylic acids which retain their nucleobase, phosphate, and 5‘-hydroxyl protecting groups are obtained from photolabile, orthogonal solid-phase synthesis supports that are based upon the o -nitrobenzyl photoredox process. , Solution-phase coupling of these protected oligonucleotides to a variety of small organic molecules and tripeptides via amide bond formation proceeds in no less than 83% isolated yield, and quite often in yields that are in excess of 90%. Although a variety of activation methods have been employed, benzotriazol-1-yloxytripyrrolidinophosphonium hexafluorophosphate (PyBOP) is the activating agent of choice.…”