论文部分内容阅读
自从1958年Lemieux等报道对六元环化合物的NMR谱以来,人们常用糖环端基H_1的化学位移值和H_2与H_2邻位偶合常数来判别糖类化合物的端基异构体。糖酯类的a-端基异构体的H_1化学位移值,常在6.8ppm,J=3.8Hz左右;β-端基异构体常在6.2—6.3ppm,J=7.5Hz附近(吡啶为溶剂)。
Since 1958 when Lemieux et al. Reported NMR spectra of 6-membered ring compounds, the chemical shifts of H 1 and the ortho-coupling constants of H 2 and H 2 were often used to determine the anomeric groups of carbohydrates. The H-1 chemical shifts of the α-anomers of sugar esters are often around 6.8 ppm at about J = 3.8 Hz; the β-anomer is often around 6.2-6.3 ppm at around J = 7.5 Hz (pyridine is Solvent).