Search

Efforts towards an effective HIV-1 vaccine have remained mainly unsuccessful. There is increasing evidence for a potential role of HLA-C-restricted CD8+ T cell responses in HIV-1 control, including our recent report of HLA-C*03:02 among African children. However, there are no documented optimal HIV-1 CD8+ T cell epitopes restricted by HLA-C*03:02; additionally, the structural influence of HLA-C*03:02 on epitope binding is undetermined. Immunoinformatics approaches provide a fast and inexpensive method to discover HLA-restricted epitopes. Here, we employed immunopeptidomics to identify HLA-C*03:02 CD8+ T cell epitopes. We identified a clade-specific Gag-derived GY9 (GTEELRSLY) HIV-1 p17 matrix epitope potentially restricted to HLA-C*03:02. Residues E62, T142, and E151 in the HLA-C*03:02 binding groove and positions p3, p6, and p9 on the GY9 epitope are crucial in shaping and stabilizing the epitope binding. Our findings support the growing evidence of the contribution of HLA-C molecules to HIV-1 control and provide a prospect for vaccine strategies. [ABSTRACT FROM AUTHOR]

The E ring of betulin rearranges and forms a cyclic ether when treated with an acid. Treatment of betulin with iodine generated hydrogen iodide in situ, which went on to promote the rearrangement at C-19 and C-20, followed by cyclization to form allobetulin. A reaction of allobetulin with 2-furoyl chloride yielded 19β,28-Epoxy-18α-olean-3β-ol-2-furoate. [ABSTRACT FROM AUTHOR]

A variety of primary alcohols and phenols were reacted with acetic anhydride at room temperature in the presence of sodium bicarbonate to produce corresponding esters in good to excellent yields. The acetylation of 4-nitrobenzyl alcohol was also carried out using other bicarbonates and carbonates. The reaction in the presence of cesium bicarbonate and lithium carbonate gave 4-nitrobenzyl acetate in excellent yield, while in the presence of Na2CO3, K2CO3, Cs2CO3, or KHCO3 the yield was in the range of 80%-95%. Calcium carbonate and cobaltous carbonate did not promote the acetylation of 4-ntirobenzyl alcohol using acetic anhydride. The acetylation of 4-nitrobenzyl alcohol was carried out using ethyl acetate, THF, toluene, diethyl ether, dichloromethane and acetonitrile, and gave good yields ranging from 75%-99%. Toluene was the best solvent for the reaction, while diethyl ether was the poorest ether was the poorest. [ABSTRACT FROM AUTHOR]

Reaction of 3,4,5-trimethoxybenzylamine and benzyl 2,3-anhydro-β-L-ribopyranoside in refluxing ethanol produced benzyl 3-deoxy-3-(3,4,5-trimethoxybenzylamino)- β-L- xylopyranoside in 72.5% yield. An attempt to synthesize the title compound by reacting neat 3,4,5-trimethoxybenzylamine with benzyl 2,3-anhydro-β-L-ribopyranoside without a solvent produced a dark brown mixture with several decomposition products. The structure of benzyl 3-deoxy-3-(3,4,5-trimethoxybenzylamino)-β-L-xylopyranoside was determined using elemental analysis, ¹H-NMR and 13C-NMR and its conformation is ¹C4. [ABSTRACT FROM AUTHOR]

A solvent system consisting of ethyl acetate, ethyl alcohol and water, in the volume ratio of 4.5:4.5:1, was developed and used to extract, at room temperature, betulin from white birch bark and antioxidants from spices (rosemary, thyme, sage, and oregano) and white oak chips. In addition, under reflux conditions, trimyristin was extracted from nutmeg using the same solvent system, and eugenol from olives was extracted using a mixture of salt water and ethyl acetate. The protocol demonstrates the use of water in organic solvents to extract natural products from plants. Measurement of the free-radical scavenging activity using by 2,2-diphenyl-1-picrylhydrazyl (DPPH) indicated that the extraction of plant material using ethyl acetate, ethyl alcohol and water (4.5:4.5:1, v/v/v) was exhaustive when carried out at room temperature for 96 h. [ABSTRACT FROM AUTHOR]

When 2-[(1S,2S)-1,2-diamino-2(2-hydroxyphenyl)ethyl]phenol (I) was reacted with 2 mole equivalents of trimethyl acetic (pivalic) anhydride in tetrahydrofuran at room temperature, 1-[(1S,2S)-1,2-bis(2-hydroxyphenyl)-2-pivaloylaminoethylamino]-2,2-dimethyl-1-propanone (II) was obtained quantitatively as the only product. The structure of the product was determined using 1H- and 13C-NMR. The COSY spectrum indicated that the single –NH was coupled to the single benzylic proton, –CH. The versality of the transformation could be used to generate additional compounds for use in various research areas. [ABSTRACT FROM AUTHOR]