-fructosides is discussed, and some tentative conclusions have been reached on the mechanisms of their furanoside-pyranoside equilibration. The change in ring size in such systems probably proceeds via an anhydro- d -fructose intermediate, rather than an acyclic intermediate. The synthetic applications of the system have been explored, and it has been shown that both d -fructosides and 2-thio- d -fructosides
摘要报道了在稀酸催化下,酮糖和酮苷反应生成酮基碳鎓离子的动力学研究,并研究了该离子与醇和
硫醇亲核试剂的后续反应。讨论了d-
果糖苷和2-
硫代-d-
果糖苷的相对反应性,并就
呋喃糖苷-
吡喃糖苷平衡的机理得出了一些初步结论。在这样的系统中,环大小的改变可能是通过脱
水果糖中间体而不是无环中间体进行的。已经探索了该系统的合成应用,并且已经表明,可以高收率合成d-
果糖苷和2-
硫代-d-
果糖苷。d-
果糖呋喃糖苷最好以
蔗糖为原料获得,而
吡喃糖苷是通过使用所需的醇或
硫醇从任何容易获得的d-
果糖吡喃糖苷(例如,甲基β)中获得的,仅获得β端基异构体。报道了三种新的2-
硫代-d-
果糖苷。