Studies of the mesomorphic behavior of bivalent carbohydrate amphiphiles
摘要:
合成了一系列由1,3-双-O-(β-D-吡喃葡萄糖基)-2-O-烷基甘油组成的同源二价糖脂,在甘油主链上带有两个糖头基团和一个烷基链。借助于偏光光学显微镜、差示扫描量热法和X射线衍射方法研究了介晶行为。同源成员表现出近晶A相,与部分双层结构一致。根据实验的 d 间距和计算得出的分子长度,表明双层结构中存在分子的部分叉指。
New polyol ether compounds and a process for their preparation. The process comprises reacting a polyol, a carbonyl compound, and hydrogen in the presence of hydrogenation catalyst, to provide the polyol ether. The molar ratio of polyol to carbonyl compound in the process is greater than 5:1.
Catalytic etherification of glycerol with short chain alkyl alcohols in the presence of Lewis acids
作者:Fei Liu、Karine De Oliveira Vigier、Marc Pera-Titus、Yannick Pouilloux、Jean-Marc Clacens、Floryan Decampo、François Jérôme
DOI:10.1039/c3gc36944g
日期:——
Here we report the homogeneously-catalyzed etherification of glycerol with short chain alkyl alcohols. Among the large variety of Brønsted and Lewis acids tested, we show here that metal triflates are not only the most active but are also capable of catalyzing this reaction with an unprecedented selectivity. In particular, in the presence of Bi(OTf)3, the targeted monoalkylglyceryl ethers were obtained with up to 70% yield. Although tested Brønsted acids were also capable of catalyzing the etherification of glycerol with alkyl alcohols, they were found however less active and less selective than Bi(OTf)3. By means of counter experiments, we highlighted that the high activity and selectivity of Bi(OTf)3 may rely on a synergistic effect between Bi(OTf)3 and triflic acid, a Brønsted acid that can be released by in situ glycerolysis of Bi(OTf)3. The scope of this methodology was also extended to other polyols and, in all cases, the monoalkylpolyol ethers were conveniently obtained with fair to good yields.
Unique spirocyclopiperazinium salt. Part 2: synthesis and structure–activity relationship of dispirocyclopiperazinium salts as analgesics
作者:Xin Wang、Feng-Li Gao、Hong-Bin Piao、Tie-Ming Cheng、Run-Tao Li
DOI:10.1016/s0960-894x(03)00213-0
日期:2003.5
Three series of spirocyclopiperazinium derivatives 5a-d, 6a-f and 17a-d were synthesized and evaluated for their in vivo analgesic activities. Compounds 5a, 17a and 17b exhibited excellent analgesic activity. Two important structure-activity relationships were observed from this study: (1) the quaternary ammonium functionality is a critical pharmacophore for analgesic activity; (2) it is important
The present invention generally relates to a process for making polyol ethers by reacting a polyol and a carbonyl compound together in the presence of hydrogen gas and a palladium hydrogenation catalyst on an acidic mesoporous carbon support.
Rubbing the right way: The directetherification of glycerol with long‐chain alcohols typically suffers from poor contact between the reaction phases. A dodecylbenzene sulfonic acid catalyst enables a better contact between the glycerol and alcohol phases, enhancing the yield of monoalkyl glyceryl ethers and offering a direct route for the synthesis of these surfactants.