Rate-controlling two-proton transfer coupled with heavy-atom motion in the 2-pyridinone-catalyzed mutarotation of tetramethylglucose. Experimental and calculated deuterium isotope effects
作者:Kjell Aake Engdahl、Haakan Bivehed、Per Ahlberg、William H. Saunders
DOI:10.1021/ja00352a040
日期:1983.7
Primary and secondary deuterium isotope effects have been measured by polarimetry, and primary isotope effects have been calculated for the classical bifunctional catalysis: 2-pyridinone-catalyzed mutarotation of 2,3,4,6-tetra-O-methyl-..cap alpha..-D-glucopyranose (..cap alpha..-TMG) in benzene. From the positively curved plot of the specific rate of epimerization vs. the mole fraction of /sup 2/H
通过旋光法测量了初级和次级氘同位素效应,并计算了经典双功能催化的初级同位素效应:2-吡啶酮催化的 2,3,4,6-四-O-甲基-..cap α 的变旋..-D-吡喃葡萄糖(..cap alpha..-TMG)在苯中。从差向异构化的特定速率与 /sup 2/H 在 OH 和 NH 氢“池”中的摩尔分数的正曲线图中,同位素效应 k/sub HH//k/sub DD/ = 3.66 +/- 0.09, k/sub HH//k/sub DH/ = 1.5, 和 k/sub HH//k/sub HD/ = 2.4 已计算。使用 ..cap alpha..-TMG 和 (1-/sup 2/H)-2,3,4,6-tetra-O-methyl-.. 测量了 1.14 +/- 0.02 的次级同位素效应。 cap alpha..-D-吡喃葡萄糖((l-/sup 2/H)-..cap alpha..-TMG),详细描述其合成,连同