نتایج جستجو برای: aromatic ammonium salts
تعداد نتایج: 92863 فیلتر نتایج به سال:
The hydroamination reaction offers a very attractive route for the synthesis of alkylated amines and their derivatives with no byproduct formation. Heterogeneous intermolecular hydroamination reactions of alkynes with aromatic amines using different inexpensive copper salts of hetropolyacid catalysts were investigated. Among heteropoly salts, copper salts of silicotungstic acid showed highest a...
Iridium-catalysed borylation of arenes is one the most widely used metal-catalysed C–H activation processes to elaborate aromatic rings. Exercising catalyst control over regioselectivity oxidative addition step remains an area active research. In this paper we describe synthesis a selection sulfonated bipyridine ligands in which there arene spacer between sulfonate group and backbone. compariso...
tetra-n-butyl ammonium hydroxide was used as a catalyst for one-pot, three component condensation reactions consisting of aromatic aldehydes, malononitrile and barbituric acid in ethanol:water solvent system at 60oc. current method has major advantages like mild reaction conditions with simple operation, high yields, by using a less toxic and lower costlier catalyst.in conclusion, we have explo...
This work describes the synthesis of a series of quaternary ammonium salts and the assessment of their in vitro antileishmanial activity and cytotoxicity. A preliminary discussion on a structure-activity relationship of the compounds is also included. Three series of quaternary ammonium salts were prepared: (i) halomethylated quaternary ammonium salts (series I); (ii) non-halogenated quaternary...
Oligoresorcinol oligomers were found to adopt a single-stranded helical conformation in alkaline water through intramolecular hydrogen bonds, of which a helix-sense bias was induced by the addition of water-soluble chiral compounds, such as ammonium salts, amines and alcohols.
While it is well known that ruminants (with the aid of rumen microorganisms) can utilize ammonium salts and urea in lieu of dietary protein,” 2 it has long been held that monogastric animals cannot.’ In view of the findings of Foster, Schoenheimer, and Rittenberg3 that dietary ammonium N15 is rapidly incorporated into rat tissue proteins, it seemed possible that the nitrogen of ammonium salts m...
A systematic approach was used to evaluate the electrospray ionization mass spectral (ESI-MS) analysis of sucrose octasulfate (SOS), an important pharmaceutical agent. SOS represents a model for other suffated carbohydrates, such as heparin and glycosaminoglycan-derived oligosaccharides that also are highly sulfated and pose difficult analytical problems. A survey of ammonium counterions showed...
Alkaloids such as cinchonidine, quinine and N-methylephedrine have been N-alkylated using polymeric benzyl halides or co-polymerized and then N-alkylated, thus affording a series of polymer-supported chiral ammonium salts which have been employed as phase-transfer catalysts in the asymmetric benzylation of an N-(diphenylmethylene)glycine ester. These new polymeric catalysts can be easily recove...
Cinchona alkaloids (quinine, quinidine, cinchonine, cinchonidine) alkylated at N(1) with chloromethyl anthracene can serve as fluorescent sensors for chiral carboxylic acids. These cinchona ammonium salts are shown to bind chiral carboxylic acids while displaying an increase in fluorescence intensity that can be utilized in determination of enantiomeric excess (ee). Sensor arrays composed of fo...
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