PubMed · 12090655
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Joseph Sherma. 2002-06-15. Planar chromatography.. https://doi.org/10.1021/ac011764f
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The preparation of 4-deazaformycin A has been achieved. The synthesis features the condensation of a suitably substituted, lithiated 4-picoline with 2,3,5-tri-O-benzyl-d-ribonolactone, dehydration of the resulting hemiacetal, and ionic hydrogenation, followed by manipulation of the protecting groups and subsequent ring closure with the formation of 7-amino-3-(beta-d-ribofuranosyl)pyrazolo[3,4-c]pyridine.
The 5'-amino-5'-phosphono derivatives of cytidine, cytosine arabinoside (ara-C), and uridine have been prepared via the corresponding nucleoside aldehydes. Phosphite addition to imines derived from the nucleoside aldehydes and p-methoxybenzylamine was efficient, and use of this amine allowed cleavage of the products to the parent amino phosphonic acids. The phosphite additions proved to be diastereoselective, with the cytidine and uridine derivatives favoring the 5'S stereochemistry and the ara-C derivative favoring the 5'R isomer. The stereochemistry of one cytidine derivative was established by single-crystal diffraction analysis, and detailed comparisons of the (13)C NMR data allowed assignments of the other amino phosphonates.
We describe the synthesis, purification, and spectral properties of new dyes and reactive labels. They absorb in the visible range between 450 and 700 nm and display analytically useful fluorescence. They were made amino-reactive by esterification with N-hydroxysuccinimide (NHS). The resulting oxysuccinimide (OSI) esters were covalently linked to the amino groups of human serum albumin (HSA) or certain DNA oligomers. Except for dyes 9 and 13, they contain one reactive group only in order to avoid cross linking of biomolecules. Labeling of amino-modified biomolecules was performed by standard protocols, and the labeled proteins and oligonucleotides were separated from the unreacted dye by gel chromatography using Sephadex G25 as the stationary phase in the case of proteins, and reversed-phase HPLC in the case of DNA oligomers. The dyes also have been used as donor-acceptor pairs in fluorescence energy transfer systems and in energy transfer cascades.