Detail of "69257-04-1"

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Polymer-supported cinchona alkaloid-derived ammonium salts as recoverable phase-transfer catalysts for the asymmetric synthesis of a-amino acids

Polymer-supported cinchona alkaloid-derived ammonium salts as recoverable phase-transfer catalysts for the asymmetric synthesis of a-amino acids. Chinchilla, Rafael; Mazon, Patricia; Najera, Carmen (Departamento de Quimica Organica and Instituto de Sintesis Organica, Universidad de Alicante, Alicante 03080, Spain). Molecules, 9(5), 349-364 (English) 2004 Molecular Diversity Preservation International. URL: http://www.mdpi.net/molecules/papers/90500349.pdf. CODEN: MOLEFW. ISSN: 1420-3049. DOCUMENT TYPE: Journal; (online computer file) CA Section: 34 (Amino Acids, Peptides, and Proteins) Section cross-reference(s): 31, 35, 67 Alkaloids such as cinchonidine, quinine and N-methylephedrine have been N-alkylated using polymeric benzyl halides or co-polymd. and then N-alkylated, thus affording a series of polymer-supported chiral ammonium salts which have been employed as phase-transfer catalysts in the asym. benzylation of an N-(diphenylmethylene)glycine ester. These new polymeric catalysts can be easily recovered by simple filtration after the reaction and reused. 833479-97-3 and 69257-04-1 are just another two chemicals used in this study. The best enantiomeric excesses were achieved when Merrifield resin-anchored cinchonidinium ammonium salts were employed. .

Improved conditions for the asymmetric synthesis of a-amino acids using Cinchona-derived anthracenylmethyl ammonium salts as chiral phase-transfer organocatalysts

All Rights Reserved. In this article, certain chemicals are used. One of their cas registry numbers is 69257-04-1 Improved conditions for the asymmetric synthesis of a-amino acids using Cinchona-derived anthracenylmethyl ammonium salts as chiral phase-transfer organocatalysts. Chinchilla, Rafael; Najera, Carmen; Ortega, Francisco J. ( Departamento de Quimica Organica, Instituto de Sintesis Organica (ISO), Universidad de Alicante, Alicante 03080, Spain). Tetrahedron: Asymmetry, Volume Date 2006, 17(24), 3423-3429 (English) 2007 Elsevier Ltd. CODEN: TASYE3. ISSN: 0957-4166. DOCUMENT TYPE: Journal CA Section: 34 (Amino Acids, Peptides, and Proteins) Section cross-reference(s): 25, 31, 67 Cinchonidine and cinchonine-derived monomeric anthracenylmethyl ammonium salts bearing different counter-anions are used as chiral organocatalysts in the enantioselective alkylation of a benzophenone-imine tert-Bu glycinate under phase-transfer conditions. Generally, an improvement of the enantioselectivity is obsd.Several substances like 69257-04-1 may be metioned in this study. when the counterions are tetrafluoroborate and hexafluorophosphate using 50% aq. KOH as the base and toluene/chloroform as the solvent. The enantioselectivities achieved are comparable and frequently higher, even working under simpler and less-strict reaction conditions and with lower organocatalyst loading, than those reported previously. ..