Lewis sulfated derivatives

A. Lubineau and R. Lemoine, Regjoselective sulfation of galactose derivatives through the sttumylene procedure. New synthesis of the 3 -(>-sulfated Lewis trisaccharide. Tetrahedron Lett 35 8795 (1994). 

N—C—O + C—C. The construction of the oxazole ring by the condensation of a-halogeno ketones with primary amides (equation 122) is the Bliimlein-Lewy synthesis (1884/1888). The method succeeds best when the resulting oxazole contains one or more aryl substituents. The use of formamide leads to oxazoles with a free 2-position and in this case it is possible that the reaction proceeds as in equation (113). 2-Aminooxazoles are produced by the action of a-halogeno ketones on urea and its derivatives (equation 123) or on cyanamide (80ZOR2185). The mercury(II) sulfate-catalyzed condensation of alkynic alcohols or their esters with primary amides leads to trisubstituted oxazoles (equation 124). 

Tracer Hybrid Receptor Model (Lewis). Lewis and Stevens (3) have derived a hybrid receptor model for describing the secondary sulfate from an SO2 point source. The resulting expression for secondary sulfate concentration M o at the receptor has the form... 

The alkylation chemistry of a considerable number of O-trimethylsilyl cyanohydrins derived from aryl and heteroaryl aldehydes has been reported by Hunig and coworkers. Tbe protected cyanohydrins are easily prepared by heating the aldehydes with trimethylsilyl cyanide in the presence of a Lewis acid. The use of dialkyl sulfates and tosylates as alkylating agents was so reported. Hata et alP failed to alkylate the anion of the adduct of trimethylsilyl cyanide and acetaldehyde, suggesting that the trimethylsilyl group is incompatible with the more basic anions derived from aliphatic aldehydes. Ficini et alP... 

Methyl-, hydroxyethyl-, hydroxypropyl-, and carboxymethyl starches, starch acetates, succinates, alkenyl succinates (Fig. 2), adipates, and phosphates, are all well-known products. Furthermore, special derivatives have also been prepared, such as vinyl-, silyl-, ° or propargyl starches, as reactive intermediates for fiirther fime-tionalization. Unusual substitution patterns can also be established by highly selective deacetylation with alkyldiamines and subsequent introduction of such functional groups as sulfates. From die analytical point of view, the most important aspects are stability under alkaline (mediylation) and acidic or Lewis-acidic (depolymerization) conditions, reactivity (such as migration, rearrangement, further substitution or addition reactions, or any intramolecular reaction), and polarity (lipophilic/hydrophilic, ionic/nonionic, acidic/basic). These properties mainly determine the analytical... 

In 1966, the first reports on the successful syntheses of NF4 salts were published by two research groups, Tolberg etal. [1] and Christe etal. [2]. Previously, it was concluded from theoretical considerations that NF4 could not form crystalline salts [3] or that only the fluoroborate, NF4BF4, might exist at low temperatures. Thus, no other hypothetical salts such as perfluoroammonium perchlorate, -sulfate, and -fluoride were thought to exist [4]. Since the first reports, numerous NF4 salts have been prepared and characterized containing counterions which are derived mainly from perfluorinated Lewis acids. 

Hasaninejad A, Zare A et al (2009) Zirconium tetrakis (dodecyl sulfate)[Zr(DS) ] as an efficient Lewis acid-surfactant combined catalyst for the synthesis of quinoxaline derivatives in aquous media. Syn Commun 39 569-579... 

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