13071-59-5Relevant articles and documents
ALTERNATIVE, SIMPLE ROUTE TO HYDROXYMETHYL CROWN ETHERS
Ctech, Bronislav
, p. 4197 - 4198 (1980)
Components for polymer-supported catalysts, hydroxymethyl-substituted 15-crown-5 and 18-crown-6 were prepared from readily available starting materials on relative simple way.
SYNTHESIS OF 2,3-DI-O-PHYTANYL-1-O-6)-MANNOSYL-α(1->2)-GLUCOSYL-α(1->1)>-SN-GLYCEROL. PURPLE MEMBRANE GLYCOLIPIDS
Boeckel, C. A. A. van,Westerduin, P.,Boom, J. H. van
, p. 2819 - 2822 (1981)
A convenient approach to the synthesis of triglycosyl-2,3-di-O-phytanyl-sn-glycerols will be presented.Special attention will be paid to the use of the following protective groups in carbohydrate chemistry: the 2,2,2-trichloroethoxycarbonyl, the 1,1,3,3-tetraisopropyldisiloxane-1,3-diyl and the o-dibromomethyl benzoyl group.
Synthesis and vesicle formation from dimeric pseudoglyceryl lipids with (CH2)m spacers: Pronounced m-value dependence of thermal properties, vesicle fusion, and cholesterol complexation
Bhattacharya, Santanu,De, Soma
, p. 2335 - 2347 (1999)
Eight new dimeric lipids, in which the two Me2N+ ion headgroups are separated by a variable number of polymethylene units [-(CH2)m-], have been synthesized. The electron micrograph (TEM) and dynamic light scattering (DLS) of their aqueous dispersions confirmed the formation of vesicular-type aggregates. The vesicle sizes and morphologies were found to depend strongly on the m value, the method, and thermal history of the vesicle preparation. Information on the thermotropic properties of the resulting vesicles was obtained from microcalorimetry and temperature-dependent fluorescence anisotropy measurements. Interestingly, the Tm values for these vesicles revealed a nonlinear dependence on spacer chain length (m value). These vesicles were able to entrap riboflavin. The rates of permeation of the OH- ion under an imposed transmembrane pH gradient were also found to depend significantly on the m value. X-Ray diffraction of the cast films of the lipid dispersions elucidated the nature and the thickness of these membrane organizations, and it was revealed that these lipids organize in three different ways depending on the m value. The EPR spin-probe method with the doxylstearic acids 5NS, 12NS, and 16NS, spin-labeled at various positions of stearic acid, was used to establish the chain-flexibility gradient and homogeneity of these bilayer assemblies. The apparent fusogenic propensities of these bipolar tetraether lipids were investigated in the presence of Na2SO4 with fluorescence-resonance energy-transfer fusion assay. Small unilamellar vesicles formed from 1 and three representative biscationic lipids were also studied with fluorescence anisotropy and 1H NMR spectroscopic techniques in the absence and the presence of varying amounts of cholesterol.
Synthesis of macrocyclic diacyl/dialkyl glycerols containing disulfide tether and studies of their effects upon incorporation in DPPC membranes. Implications in the design of phospholipase A2 modulators
Bhattacharya, Santanu,Ghosh, Sangita,Easwaran, Kalpathy R. K.
, p. 9232 - 9242 (1998)
A general method for the preparation of novel disulfide-tethered macrocyclic diacylglycerols (DAGs) has been described. Overall synthesis involved stepwise protection, acylation, and deprotection to yield the bis(ω-bromoacyl) glycerols. In the crucial macrocyclization step, a unique reagent, benzyltriethylammonium tetrathiomolybdate (BTAT), has been used to convert individual bis(ω-bromoacyl) glycerols to their respective macrocyclic disulfides. DAG 6, which had ether linkages between hydrocarbon chains and the glycerol backbone, was also synthesized from an appropriate precursor using a similar protocol. One of the DAGs (DAG 5) had a carbon- carbon tether instead of a disulfide one and was synthesized using modified Glaser coupling. Preparation of α-disulfidetethered DAG (DAG 4) required an alternative method, as treatment of the bisbromo precursor with BTAT gave a mixture of several compounds from which separation of the target molecule was cumbersome. To avoid this problem, the bisbromide was converted to its corresponding dithiocyanate, which on further treatment with BTAT yielded the desired DAG (DAG 4) in good yield. Upon treatment with the reducing agent dithiothreitol (DTT), the DAGs that contain a disulfide tether could be quantitatively converted to their 'open-chain' thiol analogues. These macrocyclic DAGs and their reduced 'open-chain' analogues have been incorporated in DPPC vesicles to study their effect on model membranes. Upon incorporation of DAG 1 in DPPC vesicles, formation of new isotropic phases was observed by 31P NMR. These isotropic phases disappeared completely on opening the macrocyclic ring by a reducing agent. The thermotropic properties of DPPC bilayers having DAGs (1-6) incorporated at various concentrations were studied by differential scanning calorimetry. Incorporation of DAGs in general reduced the cooperativity unit (CU) of the vesicles. Similar experiments with reduced 'open-chain' DAGs incorporated in a DPPC bilayer indicated a recovery of CU with respect to their macrocyclic 'disulfide' counterparts. The effect of inclusion of these DAGs on the activity of phospholipase A2 (PLA2) was studied in vitro. Incorporation of DAG 1 in DPPC membranes potentiated both bee venom and cobra venom PLA2 activities.
Percarboxylic Acid Oxidation of α-Hydroxy-Substituted Alkoxyallenes: The Unexpected Formation of Acyloxy-Substituted 1,2-Diketones and the Synthesis of Functionalized Quinoxalines
Klemme, Robby,Bentz, Christoph,Zukowski, Tomasz,Schefzig, Luise,Lentz, Dieter,Reissig, Hans-Ulrich,Zimmer, Reinhold
, p. 1491 - 1501 (2016)
Treatment of α-hydroxy-substituted methoxyallene derivatives with meta-chloroperbenzoic acid provided acyloxy-substituted 1,2-diketones in moderate yields. A mechanism for the formation of these unexpected products is proposed. The configuration of the enantiopure compound (S)-1-(3-methylquinoxalin-2-yl)-1-(4-nitrobenzoyl?oxy)propan-2-yl 3-chlorobenzoate - determined by X-ray crystal structure analysis - indicates the intermediacy of a carbenium ion during formation of the 1,2-diketones. The functionalized 1,2-diketones are valuable starting materials for a variety of products as demonstrated by the synthesis of quinoxalines, an imidazole derivative, and electron-deficient alkenes.
Synthesis and vesicle formation from novel pseudoglyceryl dimeric lipids. Evidence of formation of widely different membrane organizations with exceptional thermotropic properties
Bhattacharya, Santanu,De, Soma,George, Shaji K.
, p. 2287 - 2288 (1997)
Eight new bis-cationic dimeric lipids 2a-h have been synthesized; TEM of their aqueous dispersions confirmed the vesicle formation and from the thermal, spectroscopic, DLS and XRD studies it has been revealed that they form three different kinds of membranous aggregate depending on the m-value.
Dendritic Oligoglycerol Regioisomer Mixtures and Their Utility for Membrane Protein Research
Urner, Leonhard H.,Goltsche, Katharina,Selent, Marleen,Liko, Idlir,Schweder, Marc-Philip,Robinson, Carol V.,Pagel, Kevin,Haag, Rainer
, p. 2537 - 2542 (2020/12/30)
Dendrons are an important class of macromolecules that can be used for a broad range of applications. Recent studies have indicated that mixtures of oligoglycerol detergent (OGD) regioisomers are superior to individual regioisomers for protein extraction. The origin of this phenomenon remains puzzling. Here we discuss the synthesis and characterization of dendritic oligoglycerol regioisomer mixtures and their implementation into detergents. We provide experimental benchmarks to support quality control after synthesis and investigate the unusual utility of OGD regioisomer mixtures for extracting large protein quantities from biological membranes. We anticipate that our findings will enable the development of mixed detergent platforms in the future.
Synthesis and catalytic evaluation of acidic carbons in the etherification of glycerol obtained from biodiesel production
Chiosso, María E.,Casella, Mónica L.,Merlo, Andrea B.
, p. 107 - 114 (2020/10/29)
In this paper, the catalytic behaviour of carbonaceous system (Ccs) functionalized with –SO3H groups were studied in the etherification of refined (Gly) and crude glycerol (GlyC), with benzyl alcohol (BA). This Ccs was obtained by a synthetic method with low energetic cost in only 24 h. Its catalytic activity and selectivity were studied varying the catalyst percentage (2.5, 5 and 10 wt.%), the initial reactant molar ratio and temperature (between 80 and 120 °C). A very good catalytic performance was achieved (97 % conversion after 360 min of reaction), at 120 °C, Gly:BA = 3:1 and 10 wt.% of Ccs. The high activity can be attributed to high acid site density (6.4 mmol H+/g), that also allowed us to working at lower reaction temperature (100 °C) and with less catalyst concentration (2.5 wt.%), without observing significant loss in BA conversion. Monoether (ME1) was the major product of the reaction with 72 % selectivity. The material can be reused and still gives a notable conversion of BA (about 43 %) after three successive reuses. Finally, the Ccs was active and selective to the desired products in the etherification of crude glycerol (GlyC) derived of biodiesel industry. An important BA conversion (45 %) was obtained only reducing the water content of GlyC and without carrying out any other purification and/or neutralization treatment.
POLY(PHOSPHOESTERS) FOR DELIVERY OF NUCLEIC ACIDS
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, (2020/09/15)
Disclosed are polymers comprising the moiety A, which is a moiety of formula I: and pharmaceutically acceptable salts thereof, wherein R, R1, R2, L, n1 and n2 are as defined herein. These polymers are useful for delivering nucleic acids to subject. These polymers and pharmaceutically acceptable compositions comprising such polymers and nucleic acids can be useful for treating various diseases, disorders and conditions.
COMPOSITIONS AND METHODS FOR THE TREATMENT OF PARKINSON'S DISEASE
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, (2020/05/19)
The invention relates to the compounds of formula I, formula II and/or formula III or its pharmaceutical acceptable salts, as well as polymorphs, solvates, enantiomers, stereoisomers and hydrates thereof. The pharmaceutical compositions comprising an effective amount of compound of formula I, formula II or formula III, and methods for treating or preventing Parkinson's disease may be formulated for oral, buccal, rectal, topical, transdermal, transmucosal, intravenous, parenteral administration, subcutaneous, depot, intramuscular, syrup, or injection. Such compositions may be used to treatment or management of Parkinson's disease as well as scleroderma, restless leg syndrome, hypertension and gestational hypertension.
