tri-O-acetyl-D-galactal with alcohols and phenols is shown to give glycoside derivatives containing a 2,3-double bond. In boiling acetic acid the glycal acetate undergoes competing addition and rearrangement reactions, and ultimately gives a diene which is assigned a pyranoid structure; crystalline 1,3,4,6-tetra-O-acetyl-2-deoxy-α-D-lyxo-hexose, 3,4,6-tri-O-acetyl-D-gulal, and 1,4,6-tri-O-acetyl-2,3-didehydro-2
显示三-O-乙酰基-
D-半乳糖与醇和
酚的反应产生含有2,3-双键的糖苷衍
生物。在沸腾的
乙酸中,
乙酸乙二醛经过竞争性加成和重排反应,最终生成被分配为
吡喃类结构的二烯。结晶1,3,4,6-四ø -乙酰基-2-脱氧- α- d -来苏-hexose,3,4,6-三- ö乙酰基d -gulal,和1,4,6-三ø -乙酰基-2,3-二脱氢-2,3-二脱氧α- d -苏-己糖已被分离。通过在
乙酸中加热饱和
乙酸盐可以得到相同的产物。在添加的
甲磺酸的存在下,仅少量的不饱和化合物由该
乙二酸酯形成。