59404-48-7Relevant academic research and scientific papers
Polymerization of supramolecular assemblies: Comparison of lamellar and inverted hexagonal phases
Srisiri, Warunee,Lee, Youn-Sik,Sisson, Thomas M.,Bondurant, Bruce,O'Brien, David F.
, p. 15397 - 15414 (1997)
Since the first reports of the polymerization of hydrated bilayers in the early 1980s, a wide variety of polymerizable groups and lipids has been successfully employed. Among the various strategies explored for the polymerization of lamellar phases, a particularly useful method relies on the design of suitable polymerizable amphiphiles, which upon hydration form assemblies that can then be polymerized with retention of structure. We have recently extended this strategy to successfully polymerize the inverted hexagonal (H(II)) phase. This report is the first comparison of radical chain polymerizations in lamellar and H(II) phases. The number average degree of polymerization of polymers obtained in both lamellar and H(II) phases depended strongly on the initiation chemistry, but were insensitive to the lipid phases. The immediate benefit of these studies is the knowledge that polymer size can be varied extensively in both phases in order to obtain different materials properties.
The total synthesis of (-)-tetrahydrolipstatin
Bodkin, Jennifer A.,Humphries, Edward J.,McLeod, Malcolm D.
, p. 795 - 803 (2007/10/03)
Careful control during the bromolactonization of β,γ-unsaturated acid (4) was required to regioselectivity afford the trans-β-lactone (3) as the major diastereomer. Radical debromination of (3) followed by a three-step sequence of reactions afforded the lipase inhibitor (-)-tetrahydrolipstatin (1).
The total synthesis of (-)-tetrahydrolipstatin
Bodkin, Jennifer A.,Humphries, Edward J.,McLeod, Malcolm D.
, p. 2869 - 2872 (2007/10/03)
Careful control during the bromolactonisation of β,γ-unsaturated acid 3 was required to afford regioselectively the trans-β-lactone 4 as the major diastereomer. Radical debromination of 4 followed by a three-step sequence of reactions afforded the lipase inhibitor (-)-tetrahydrolipstatin.
Expedient synthesis of unsaturated amide alkaloids from Piper spp: Exploring the scope of recent methodology
Strunz, George M.,Finlay, Heather J.
, p. 419 - 432 (2007/10/03)
The Sakai aryl aldehyde - cyclic ketone aldol - Grob fragmentation sequence was extended to cinnamaldehyde and cyclohexanone, and the product was elaborated to analogues of the alkaloid piperstachine. The effects of substituents on the reaction involving cinnamaldehyde were studied. The aldol-fragmentation sequence failed with benzaldehyde when cyclooctanone or cyclobutanone was substituted for cyclohexanone or cyclopentanone, and the reasons for this failure were examined. Four-carbon Wittig homologation of the piperonal-cyclobutanone aldol-fragmentation product, a hypothetical route to alkaloids such as retrofractamide A, was thus not viable. Instead, three-carbon homologation of the readily available piperonal-cyclopentanone product, using alkyne chemistry recently disclosed by Lu and Trost, afforded these alkaloids in excellent overall yield. The alkyne isomerization was also used to effect efficient syntheses of pellitorine and several other non-aromatic 2E,4E-dienoic Piper amide alkaloids. The Sakai aryl aldehyde - cyclic ketone aldol - Grob fragmentation sequence was extended to cinnamaldehyde and cyclohexanone, and the product was elaborated to analogues of the alkaloid piperstachine. The effects of substitutents on the reaction involving cinnamaldehyde were studied. The aldol-fragmentation sequence failed with benzaldehyde when cyclooctanone or cyclobutanone was substituted for cyclohexanone or cyclopentanone, and the reasons for this failure were examined. Four-carbon Wittig homologation of the piperonal-cyclobutanone aldol-fragmentation product, a hypothetical route to alkaloids such as retrofractamide A, was thus not viable. Instead, three-carbon homologation of the readily available piperonal-cyclopentanone product, using alkyne chemistry recently disclosed by Lu and Trost, afforded these alkaloids in excellent overall yield. The alkyne isomerization was also used to effect efficient syntheses of pellitorine and several other non-aromatic 2E,4E-dienoic Piper amide alkaloids.
Permeability Characteristics of Polymeric Bilayer Membranes from Methacryloyl and Butadiene Lipids
Dorn, K.,Klingbiel, R. T.,Specht, D. P.,Tyminski, P. N.,Ringsdorf, H.,O'Brien, D. F.
, p. 1627 - 1633 (2007/10/02)
Four polymerizable lipids were synthesized and used for the formation of synthetic bilayer membranes (vesicles).Two of the lipids were methacryloyl ammonium lipids, one with a methacrylamide at the hydrophilic head group of the lipid (α-MA) and one with a methacrylate group at the hydrophobic tail of the lipid (ω-MA).Thermally initiated polymerization of the monomeric bilayer vesicles gave polymers with retention of vesicles structure.The size distribution of the aqueous suspension was not altered significantly on polymerization, and the membranes continued to entrap glucose.The permeability of poly(α-MA) and poly(ω-MA) membranes is about half that of the unpolymerized bilayers.Previously we reported that about 500 monomer units were found per average polymer chain of poly(α-MA) and poly(ω-MA), which shows that there are several (20 to 100) polymer chains per vesicle (Dorn, K. et al.Makromol.Chem., Rapid Commun. 1983, 4, 513).Two butadiene lipids, one based on a phosphatidylcholine (PC) structure, and one with a taurine head group, also formed bilayer membranes, which could be photopolymerized by exposure to ultraviolet light.These lipids have a sorbate unit (λmax 257 nm) in each of the two hydrocarbon chains, which allows the photopolymerization to proceed with the formation of cross-links.Poly(butadiene PC) membranes effectively entrapped glucose for at least a week and were not disrupted by the use of the surfactant Triton X-100.
