在进行碳水化合物这章教学的时候。往往对于识别糖的 Haworth 式所表示的系属(D__系或L__系)和异头物的构型(α__型或β__型)学生感到困难。其原因是目前已有的教材中,缺乏通用的直接识别的方法,例如:有的教材对α__型的定义是“半缩醛碳上的羟基和决定构型的羟基在碳链的同侧叫做α__型”。这只能对 Tol-lens 式的环状结构的认别有直接的指导意义,因为在 Haworth 式中对吡喃型的已醛糖或呋喃型的己酮糖的决定构型的羟基已用去成环了。与半缩醛羟基没有直观的同边异边关系。又如有的教材又这样定义“D__系巳醛糖中 C_1上的羟基与 C_5上的—CH_2OH在顺位为β__正位异构体”这对识别 D__吡喃型已醛糖确实很方便,但是对呋喃型的已醛糖和吡喃型的己酮糖又无能为力了如: While teaching carbohydrate this chapter. Often it is difficult for students to identify the type (D__ or L__ line) and anomeric configurations (α__ or β__ type) of the Haworth-type sugars. The reason is that there is no common method for direct identification in the existing teaching materials. For example, some teaching materials define α__type as “the hydroxyl group on the hemiacetal carbon and the hydroxyl group that determines the configuration are on the same side of the carbon chain Called α__ type. ” This can only be of direct interest in the identification of Tol-lens ring structures since the hydroxyl group of the decisive configuration of the pyran-type aldohexose or furan-type ketoses in the Haworth formula has been used Looping There is no intuitive same-hemline relationship with hemiacetal hydroxyl groups. Another example is the textbook and the definition of “D__ Department of Aldehydes in C_1 Aldehydes and C_5 on the -CH_2OH in the order of β__ anomer” which identifies D__ pyran aldohexose indeed Very convenient, but furan-aldose and pyran-type keto-sugar can not do anything like: