XLVIII.—The phosphoric acids
نویسندگان
چکیده
منابع مشابه
Highly enantioselective Biginelli reaction catalyzed by SPINOL-phosphoric acids.
A highly enantioselective Biginelli reaction promoted by chiral spirocyclic SPINOL-phosphoric acids has been developed. Under the optimized conditions with 5 mol% catalyst loading, a wide range of optically active dihydropyrimidinethiones (DHPMs) were obtained in high yields (up to 98%) with good to excellent enantioselectivities (up to 99% ee). The synthetic utility of this method was demonstr...
متن کاملHighly enantioselective hydrogenation of enamides catalyzed by chiral phosphoric acids.
A highly enantioselective hydrogenation of enamides catalyzed by a dual chiral-achiral acid system was developed. By employing a substoichiometric amount of a chiral phosphoric acid and acetic acid, catalyst loadings as low as 1 mol % of the chiral catalyst were sufficient to provide excellent yield and enantioselectivity of the reduction product.
متن کاملReaction of Stannyl Esters of Phosphorus Acids with Sulfonic Acids Chlorides and Carboxylic Acids Anhydrides. A Novel Synthesis of Phosphoric-Sulfonic and Phosphoric-Carboxylic Anhydrides
Mixed anhydrides of phosphorus sulfonic acids RR'P(O)OSOzR" 1 are of interest in the biological transfer of sulfates'. In the chemical synthesis of oligonucleotides, phosphoric sulfonic anhydrides 1 (R', R = nucleoside) are postulated as important and reactive intermediatesw-s-. Anhydrides 1 were also suggested as intermediates in biooxidation of thiolophosphates'. Structural analogues of anhyd...
متن کاملSem Analysis of the Acid-etched Enamel Patterns Promoted by Acidic Monomers and Phosphoric Acids
OBJECTIVE Although self-etching bonding systems (SES) are indicated to prepare dental enamel for bonding, concerns have been expressed regarding their effectiveness. The aim of this study was to analyze the etching pattern (EP) of nine SES in comparison with 35% and 34% phosphoric acid etchants (FA) on intact (IN) and ground (GR) enamel surface. MATERIALS AND METHODS Twenty-two human third mo...
متن کاملThe enantiomeric excess determination and dynamic behaviour of cyclic phosphoric acids used for resolution
A method is presented to determine the enantiomeric excess (ee) of phosphoric acids 1, which are extensively used as resolving agents, by means of diastereomeric salt formation with chiral amines. The unexpected dynamic behaviour of these systems leads us to postulate a model, which we refer to as non-reciprocal behaviour.
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ژورنال
عنوان ژورنال: J. Chem. Soc., Trans.
سال: 1911
ISSN: 0368-1645
DOI: 10.1039/ct9119900384