In this study, we have designed, synthesized and full characterized a novel biological based acidic nano organocatalyst via condensations reaction of uric acid phosphorous acid. The obtained compound was named theacrine tetrakis(phosphonic acid) (TTPA) prepared under refluxing ethanol. This new applied as an efficient recyclable catalyst for the preparation pyridines with indole moieties cooper...

The conformational characteristics of abasic 1-deoxy sugars 1,2, and 3 and pentofuranose moieties in 2‘,3‘dideoxy-[ddA (6), ddG (7), ddC (S)], 2’-deoxy-[dA (9), dG (lo), dC (ll)], and ribo-@-D-nucleosides [Ade (12), Gua (13), Cyt (14)] were established through the analysis of vicinal proton-proton coupling constants extracted from their 500-MHz lH-NMR spectra recorded at 20 K intervals in the t...

Solid-phase oligosaccharide synthesis offers the promise of providing libraries of oligosaccharides for glycomics research. A major stumbling block to solid-phase oligosaccharide synthesis has been a lack of general methods for the stereoselective installation of 1,2-cis-glycosides, and intractable mixtures of compounds are obtained if several such glycosides need to be installed. We have prepa...

A series of light-activatable perfluorophenylazide (PFPA)-conjugated carbohydrate structures have been synthesized and applied to glycoarray fabrication. The glycoconjugates were structurally varied with respect to anomeric attachment, S-, and O-linked carbohydrates, respectively, as well as linker structure and length. Efficient stereoselective synthetic routes were developed, leading to the f...

The stereochemistry of the ketosidic bond of sialic acid has been elucidated by a study of the two anomeric methyl ketosides. Isomer I was prepared by Koenig.+Knorr synthesis, and isomer II by direct methylation with methanol and an acid catalyst. These two anomeric configurations were established by conversion with periodate-borohydride to III and IV, respectively, followed by lactonization of...

The molecular structure of the stable conformation of phosphonic acid in gas phase has beencomputed by employing complete geometry optimization in Density Functional Theory(DFT) methods. The methods used for calculations are B3LYP, BP86 and B3PW91 that havebeen studied in two series of basis sets: D95** and 6-31+G(d,p) for hydrogen and oxygenatoms; LANL2DZ for phosphorus. Bond lengths and angle...

There has been increasing interest in the construction of liposomes containing a targeting reagent for target-specific drug delivery. Glycoconjugates that can be recognized by transmembrane glycoprotein receptors have been extensively used to form glyco-liposomal drug carriers. However, the impact of anomerism, which is a common identity of natural glycoconjugates, on the glyco-liposomal proper...

In aqueous solution Dfructose 1,6-bisphosphate (FBP)? exists as equilibrium mixture of 20 + 4% a-D-fructofuranose 1,6-bisphosphate, 80 f 10% /3-Dfructofuranose 1,6-bisphosphate, and less than 1.5% of the open chain [l-4] . The two anomeric forms are spontaneously interconvertible via the open chain tautomer. The first order rate constant for the ring opening of the o!-D-fructofuranose 1,6-bisph...

Disaccharides tagged with p-aminobenzoic acid (ABA) were separated by capillary electrophoresis (CE) and analyzed on-line with negative ion electrospray ionization tandem mass spectrometry (ESI/MS/MS). The formation of glycosylamine instead of reductive amination was selected as the derivatization reaction. In negative ion ESI, the glycosylamine approach provides more information on linkage and...

A new and completely diastereoselective method for the introduction of fluorine into a noncarbohydrate sugar ring precursor has been developed. The use of N-fluorodibenzenesulfonimide (5) for the electrophilic fluorination of chiral lactone 4, which is derived from L-glutamic acid, yields the key intermediate 6. This is transformed into an anomeric acetate 8 and is used for the synthesis of a n...