Synthesis of Novel Asymmetrical Single-Chain Phosphoglycol-Based Bolaamphiphiles
摘要:
The synthesis of long-chain 1,-diols with orthogonal cleavable protecting groups can be effectively performed with the use of the Grignard coupling reaction, successfully leading to the preparation of novel asymmetrical single-chain phosphoglycol-based bolaamphiphilesa side-product that always occurred during the synthesis of symmetrical bolalipids. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications (R) for the following free supplemental resource(s): Full experimental and spectral details.]
Structure–property relationships in a series of diglycerol tetraether model lipids and their lyotropic assemblies: the effect of branching topology and chirality
preparation of diglyceroltetraethers was either performed by condensing suitable blocked monoglycerol diethers by Grubbs metathesis or by reaction of the transmembrane C32-chain with blocked glycerols followed by further alkylation steps. Finally, we could show that the resulting lipids can form closed lipid vesicles comparable to the opticallypure counterparts. Therefore, these much simpler lipids compared
double bond of the α,ω‐dicarboxylic fatty acid self‐metathesisproducts is shifted selectively to the statistically much‐disfavored α,β‐position in a catalytic dynamic isomerizing crystallization approach. “Chain doubling” by a subsequent catalytic olefinmetathesis step, which overcomes the low reactivity of this substrates by using waste internal olefins as recyclable co‐reagents, yields ultra‐long‐chain
从常见的单不饱和脂肪酸开始,揭示了一种策略,该策略通过两个可扩展的催化步骤序列提供超长的脂肪族α,ω-双官能结构单元,实际上使起始原料的链长增加了一倍。在催化动态异构化结晶方法中,α,ω-二羧酸脂肪酸自复分解产物的中心双键选择性地转移到统计学上不利的α,β-位置。通过随后的催化烯烃复分解步骤实现“链加倍”,该步骤通过使用废弃的内部烯烃作为可回收的共试剂克服了这种底物的低反应性,从而产生了具有精确链长的超长链α,ω-双官能结构单元,如C 48所示链。这些结构的独特性体现在由这些遥螯单体产生的脂肪族聚酯的无与伦比的熔点(T m = 120°C),以及它们自组装成聚乙烯类单晶的过程。
General Synthesis and Aggregation Behaviour of New Single-Chain Bolaphospholipids: Variations in Chain and Headgroup Structures
The chemical structures of polymethylene-1,omega-bis(phosphocholines) that self-assemble into nanofibres was modified on the one hand in the hydrophobic chain region, by introduction of sulfur and oxygen atoms, and on the other hand by variation of the polar headgroupstructure with functionalised tertiary amines. The temperature-dependent self-assembly of these novel bolaphospholipids into nanofibres
Chain Length Dependence of Intramolecular Excimer Formation with 1,<i>n</i>-Bis(1-pyrenylcarboxy)alkanes for <i>n</i> = 1−16, 22, and 32
作者:Klaas A. Zachariasse、Antonio L. Maçanita、Wolfgang Kühnle
DOI:10.1021/jp991611k
日期:1999.10.1
Time-resolved and photostationary measurements in alkane solvents as a function of temperature are presented for the 1,n-bis(1-pyrenylcarboxy)alkanes (1PC(n)1PC, n = 1-16, 22, 32) with n methylene groups in the chain. For all compounds except 1PC(1)1PC intramolecular excimer fluorescence is observed. From fluorescence decay analysis and quenching data, the rate constant k(a) of excimer formation in the series 1PC(n)1PC is determined as a function of chain length. The value of k(a), as well as that of the excimer-to-monomer fluorescence quantum yield ratio Phi'/Phi, peaks at n = 5 and then gradually decreases with increasing n. These results are in clear contrast to those obtained previously with the 1,n-di(1-pyrenyl)alkanes (1Py(n)1Py), where Phi'/Phi, reaches its maximum at n = 3, with a sharp minimum (no excimer formation) at n = 7. This difference is attributed to a reduced steric hindrance at the excimer configuration (k(a)) and to dimer formation in the electronic ground state between the pyrenylcarboxy end groups in 1PC(n)1PC (Phi'/Phi). Both effects arise from the absence of methylene hydrogens next to the pyrenyl moieties of these molecules, which hydrogens prevent excimer formation in the case of 1Py(7)1Py.
Synthesis of new bifluorophoric probes adapted to studies of donor-donor electronic energy transfer in lipid systems
作者:Irina V Grechishnikova、Lennart B.-Å Johansson、Julian G Molotkovsky
DOI:10.1016/0009-3084(96)02537-6
日期:1996.6
A series of bifluorophoric fluorescent probes with identical pairs of chromophores have been synthesized. The fluorophores are 9-anthryl, 3-perylenyl and rhodamine 101, and they are separated by a long rigid (bisteroid) or flexible (dotriacontane) diol spacer. The probes are designed for studies of intra- and intermolecular electronic energy transfer in lipid systems such as model and biological membranes. They are shown to incorporate in phosphatidylcholine vesicles with an hitherto unknown orientation.