A Simple and Efficient Method for Direct Acylation of Acetals with Long Alkyl-Chain Carboxylic Acid Anhydrides
作者:Stephan D. Stamatov、Jacek Stawinski
DOI:10.1016/s0040-4020(00)00924-8
日期:2000.12
We have developed an efficient and simple method for direct transformation of acetals to carboxylicacid esters. The method consists of treatment of acetals with carboxylic anhydrides in the presence of borontrifluoride etherate as a catalyst and affords the corresponding ester derivatives in high yields with retention of configuration in the alcohol moiety. Some mechanistic aspects of this synthetically
Antivesiculation and Complete Unbinding of Tail-Tethered Lipids
作者:Kuo-Chih Shih、Geoffray Leriche、Chung-Hao Liu、Jibao He、Vijay T. John、Justin Fang、John G. Barker、Michihiro Nagao、Lin Yang、Jerry Yang、Mu-Ping Nieh
DOI:10.1021/acs.langmuir.3c02663
日期:2024.1.23
We report the effect of tail-tethering on vesiculation and completeunbinding of bilayered membranes. Amphiphilic molecules of a bolalipid, resembling the tail-tethered molecular structure of archaeal lipids, with two identical zwitterionic phosphatidylcholine headgroups self-assemble into a large flat lamellar membrane, in contrast to the multilamellar vesicles (MLVs) observed in its counterpart,
我们报告了尾部束缚对囊泡形成和双层膜完全解离的影响。波脂的两亲性分子,类似于古细菌脂质的尾部束缚分子结构,具有两个相同的两性离子磷脂酰胆碱头基,自组装成大的平坦层状膜,这与在其对应物单极非束缚两性离子中观察到的多层囊泡(MLV)形成鲜明对比脂质。通过小角 X 射线散射 (SAXS) 和低温透射电子显微镜 (cyro-TEM) 证实了抗水结作用。随着膜的净电荷为零和更高的弯曲刚度(通过中子自旋回波(NSE)光谱证实),当前的膜理论将预测,由于占主导地位的范德华力,膜应该彼此堆叠(也称为“结合”)吸引力,而非堆积(“解绑”)膜的结果表明该理论需要包括非囊泡结构的熵贡献。该报告开创了对两亲物尾部束缚如何影响结构的理解,从而能够更好地控制最终的纳米级形态。
Sterol-Modified Phospholipids: Cholesterol and Phospholipid Chimeras with Improved Biomembrane Properties
作者:Zhaohua Huang、Francis C. Szoka
DOI:10.1021/ja8065557
日期:2008.11.19
We synthesized a family of sterol-modified glycerophospholipids (SML) in which the sn-1 or sn-2 position is covalently attached to cholesterol and the alternative position contains an aliphatic chain. The SML were used to explore how anchoring cholesterol to a phospholipid affects cholesterol behavior in a bilayer. Notably, cholesterol in the SML retains the membrane condensing properties of free cholesterol regardless of the chemistry or position of its attachment to the glycerol moiety of the phospholipid. SMLs by themselves formed liposomes upon hydration and in mixtures between an SML and diacylglycerophospholipids (C14 to C18 chain length) the thermotropic phase transition is eliminated at the SML equivalent of about 30 mol % free cholesterol. Osmotic-induced contents leakage from SML (C14-C18) liposomes depends upon the linkage and position of cholesterol but in general is similar to that observed in 3/2 diacylphosphatidylcholine/cholesterol (mole ratio) liposomes. SML liposomes are exceptionally resistant to contents release in the presence of serum at 37 degrees C. This is probably due to the fact that SML exchange between bilayers is more than 100 fold less than the exchange rate of free cholesterol in the same conditions. Importantly, SML liposomes containing doxorubicin are as effective in treating the murine C26 colon carcinoma as Doxil, a commercial liposome doxorubicin formulation. SMLs stabilize bilayers but do not exchange and hence provide a new tool for biophysical studies on membranes. They may improve liposomal drug delivery in organs predisposed to the extraction of free cholesterol from bilayers, such as the skin, lung, or blood.
Tully, Sarah E.; Cravatt, Benjamin F., Journal of the American Chemical Society, 2010, vol. 132, p. 3264 - 3265