“…One unit of esterase activity is defined as the amount of enzyme releasing 1 lmol of product per min under assay conditions. In order to determine activity of the enzyme towards carbohydrate esters, two substrates, namely glucose penta-acetate (5-AcGlu) and xylose tetra-acetate (4-Ac-Xy) were synthesized using the protocol described by Wolfrom et al (Wolfrom et al, 1931). Acetylation was confirmed by mass spectrometry and NMR.…”
“…One unit of esterase activity is defined as the amount of enzyme releasing 1 lmol of product per min under assay conditions. In order to determine activity of the enzyme towards carbohydrate esters, two substrates, namely glucose penta-acetate (5-AcGlu) and xylose tetra-acetate (4-Ac-Xy) were synthesized using the protocol described by Wolfrom et al (Wolfrom et al, 1931). Acetylation was confirmed by mass spectrometry and NMR.…”
“…The reaction between aldoses and alkanethiols in concentrated aqueous acid, at about 0°, leads to the formation of the acyclic dithioacetals in high yield when these products are removed from the reaction sphere by crystallization2 or by rapid neutralization of the acid. 3 If this, apparently initial, product is not so removed or if the dithioacetal is put back into the system,4 1-thioglycosides are formed and hydrolysis to the aldose occurs.…”
“…Compound 1 was successfully converted into 5-Bn in 69% and 5-Me in 75% overall yields in nine steps, respectively. 1 Synthesis of the Substrate for Introducing the 13 C Label at the 5 Position of d -Ribose a a Reagent and conditions: (a) methyl ribosylation, 5- O -dimethoxytritylation, 2,3-di- O -benzylation, dedimethoxytritylation at the 5 position; (b) EtSH, concd HCl, 0 °C by the method of Stahley et al; (c) ROH (benzyl and methyl alcohol), HgO, HgCl 2 , CaSO 4 , 70 °C by the method of Serfontein et al; (d) 4-Bn : NaIO 4 , 5 mM H 2 SO 4 in EtOH/H 2 O (9/1), rt; 4-Me : NaIO 4 in EtOH/H 2 O (9/1), rt. …”
Section: Resultsmentioning
confidence: 99%
“… a Reagent and conditions: (a) methyl ribosylation, 5- O -dimethoxytritylation, 2,3-di- O -benzylation, dedimethoxytritylation at the 5 position; (b) EtSH, concd HCl, 0 °C by the method of Stahley et al; (c) ROH (benzyl and methyl alcohol), HgO, HgCl 2 , CaSO 4 , 70 °C by the method of Serfontein et al; (d) 4-Bn : NaIO 4 , 5 mM H 2 SO 4 in EtOH/H 2 O (9/1), rt; 4-Me : NaIO 4 in EtOH/H 2 O (9/1), rt. …”
The present efficient synthesis of [5'-13C]ribonucleosides and 2'-deoxy[5'-13C]ribonucleosides is characterized by the synthesis of the D-[5-13C]ribose derivative as an intermediate via the Wittig reaction of 4-aldehydo-D-erythrose dialkyl acetals with Ph3P13CH3I-BuLi to introduce the 13C label at the 5-position of a pentose. This was followed by the highly diastereoselective osmium dihydroxylation for the preparation of 2,3-di-O-benzyl-D-[5-13C]ribose dialkyl acetal and the cyclization from D-[5-13C]ribose dialkyl acetal derivatives to the alkyl D-[5-13C]ribofuranoside derivative by the use of LiBF(4). The obtained D-[5-13C]ribose derivative was converted into [5'-13C]ribonucleosides and subsequently into the corresponding 2'-deoxynucleosides.
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