Search results for "raft"

Regulation of Plant Transporters by Lipids and Microdomains

2010

Transporters in the broad sense, that is, carriers, pumps, and channels, are proteins inserted in a lipid bilayer separating two cellular compartments. This lipid bilayer is not only the physical support of such proteins, but also a powerful way to regulate their activity. This chapter will first summarize the different means by which lipids can regulate the activity of transmembrane proteins (including the physical properties of the bilayer, its dynamic lateral compartmentalization, and the presence of particular lipid species acting as cofactors). It will then illustrate these general rules with examples of such regulations found in plant literature and, as a reference, in animal studies.

ChemInform Abstract: Unexpected Formation of a 1,2-Dichloroacenaphthylene in a Friedel-Crafts Reaction with Chloral Hydrate.

2012

Unexpected Formation of a 1,2-Dichloroacenaphthylene in a Friedel-Crafts Reaction with Chloral Hydrate

2012

An unprecedented rearrangement was encountered during an attempted alkylation of an electron-rich naphthalene with chloral hydrate. The reaction produced a dichlorinated acenaphthylene and presumably involves the intermediate formation of a chloronium ion which is opened to produce the five-membered ring of the final product.

Organocatalytic Enantioselective Friedel‐Crafts Alkylation Reactions of Pyrroles

2021

Chemical modification of porous calcium hydroxyapatite surfaces by grafting phenylphosphonic and phenylphosphite acids

2006

Abstract It is well known that the incorporation of organic molecules can provide an effective route to modify the surface properties of apatite ceramics. The present study shows that phosphonates can react with calcium ions to control the formation of the hydroxyapatite structures. The grafting of C6H5PO(OH)2 (PPOH) and C6H5PO(OH)H (PPH) was used to increase the specific surface area as well as the porosity of hydroxyapatite materials. The higher specific surface area for HAp treated by PPOH is around 267 m2/g compared to the pure HAp (140 m2/g). The phenyl (C6H5) groups are removed by thermal treatment around 500 °C. After treatment at 800 °C, organoapatites (PP-HAp) are converted to stoi…

ChemInform Abstract: Indirect Regioselective Heteroarylation of Indoles Through a Friedel-Crafts Reaction with (E)-1,4-Diaryl-2-buten-1,4-diones.

2010

Abstract A two-step synthesis of 3-heteroaryl indoles has been developed. The first step of the sequence involves a Friedel–Crafts alkylation of indoles with 1,4-diaryl-2-buten-1,4-diones to give the corresponding indoles bearing a 1,4-dicarbonyl moiety. The reaction is catalyzed by InCl 3 and takes place with good yields. Cyclization of the diones under different Paal–Knorr conditions allows to prepare indoles substituted at the C3 position with 3-furanyl, 3-pyrrolyl- and 3-thienyl moieties.

Indirect regioselective heteroarylation of indoles through a Friedel–Crafts reaction with (E)-1,4-diaryl-2-buten-1,4-diones

2009

Abstract A two-step synthesis of 3-heteroaryl indoles has been developed. The first step of the sequence involves a Friedel–Crafts alkylation of indoles with 1,4-diaryl-2-buten-1,4-diones to give the corresponding indoles bearing a 1,4-dicarbonyl moiety. The reaction is catalyzed by InCl 3 and takes place with good yields. Cyclization of the diones under different Paal–Knorr conditions allows to prepare indoles substituted at the C3 position with 3-furanyl, 3-pyrrolyl- and 3-thienyl moieties.

Organocatalytic asymmetric addition of naphthols and electron-rich phenols to isatin-derived ketimines: highly enantioselective construction of tetra…

2015

A quinine-derived thiourea organocatalyst promoted the highly enantioselective addition of naphthols and activated phenols to ketimines derived from isatins. The reaction afforded chiral 3-amino-2-oxindoles with a quaternary stereocenter in high yields (up to 99%) with excellent enantioselectivity (up to 99% ee). To the best of our knowledge, this transformation is the first highly enantioselective addition of naphthols to ketimines

Poly(glycolide) multi-arm star polymers: Improved solubility via limited arm length.

2010

Due to the low solubility of poly(glycolic acid) (PGA), its use is generally limited to the synthesis of random copolyesters with other hydroxy acids, such as lactic acid, or to applications that permit direct processing from the polymer melt. Insolubility is generally observed for PGA when the degree of polymerization exceeds 20. Here we present a strategy that allows the preparation of PGA-based multi-arm structures which significantly exceed the molecular weight of processable oligomeric linear PGA (<1000 g/mol). This was achieved by the use of a multifunctional hyperbranched polyglycerol (PG) macroinitiator and the tin(II)-2-ethylhexanoate catalyzed ring-opening polymerization of gly…

Preparation and characterization of organofunctionalized bentonite clay bearing aminophosphonic groups in heavy metal uptake

2019

Abstract Bentonite (Bnt) with covalently immobilized N-propylaminodi(methylenephosphonic) groups (Bnt-ADPA) was obtained through a two-step synthesis including aminosilanization and phosphorylation of resulting aminobentonite through Moedritzer-Irani reaction. The grafting of an aminosilane layer in the interplanar space of the bentonite was investigated by XRD, and the presence of N and P-containing groups was confirmed by FTIR, 31P and 29Si MAS NMR. The immobilization of the organic functional groups increased the interplanar distance in bentonite matrix at 52% that essentially improved filtration properties compared to raw bentonite. The number of surface acid groups was evaluated to 0.8…