摘要描述了全部四种脱氧氟-α-d-吡喃葡萄糖基磷酸酯的合成。确定了其酸催化水解的速率常数,并且显示出氟取代在降低速率方面具有显著作用,特别是当取代邻近异头中心时。在25℃下在m HClO 4中测量的相对速率常数对于α-d-吡喃葡萄糖基磷酸酯和2-,3-,4-和6-脱氧氟衍生物分别为60.30:1.00:7.05:3.97:16.5。详细研究了2-脱氧-2-氟-α-d-吡喃葡萄糖基磷酸酯的水解,确定了4.1 eu(m反应物)和113.5 kJ.mol -1的活化熵和焓。在60°m HClO 4中的溶液中,研究了其水解的pH依赖性,并测定了单阴离子水解的速率常数(k M = 1。因此,提取了88×10 -6 s -1)和中性(k N = 6.23×10 -5 s -1)的物种。如所预期的,单阴离子的水解不受氟取代的显着影响。根据这些发现,合理化了几种机械上不同的酶利用这些氟化底物的能力或无能为力。
Ketoheptoses, seven-carbon sugars, were recognized to display pharmacological properties that are potentially suitable for in vivo diagnostic of diabetes and cancers using ¹9F-MRI. The present paper describes efficient syntheses towards ketoheptoses and exemplary a series of regioisomeric fluoro derivatives of d-gluco-hept-2-ulose. ketoheptose - fluoro d-glucoheptulose - Petasis reagent - Selectfluor
GLYCOSYLTRANSFERASE REVERSIBILITY FOR SUGAR NUCLEOTIDE SYNTHESIS AND MICROSCALE SCANNING
申请人:Thorson Jon S.
公开号:US20130004979A1
公开(公告)日:2013-01-03
The present invention generally relates to materials and methods for exploiting glycosyltransferase reversibility for nucleotide diphosphate (NDP) sugar synthesis. The present invention provides engineered glycosyltransferase enzymes characterized by improved reaction reversibility and expanded sugar donor specificity as compared to corresponding non-mutated glycosyltransferase enzymes. Such reagents provide advantageous routes to NDP sugars for subsequent use in a variety of biomedical applications, including enzymatic and chemo-enzymatic glycorandomization.