نتایج جستجو برای: diastereoisomers

تعداد نتایج: 351  

Journal: :Acta crystallographica. Section C, Crystal structure communications 2004
Peter J Steel Margaret A Brimble Brian Hopkins David Rennison

The structures of two diastereoisomers of norbormide [systematic name: 5-[hydroxy(phenyl)(2-pyridyl)methyl]-8-[phenyl(2-pyridyl)methylene]-3a,4,7,7a-tetrahydro-4,7-methano-1H-isoindole-1,3(2H)-dione], viz. the unsolvated molecule, C(33)H(25)N(3)O(3), and the ethyl acetate hemisolvate, C(33)H(25)N(3)O(3).0.5C(4)H(8)O(2), have been determined unambiguously. They differ in the relative stereochemi...

Journal: :Molecules 2009
Karl Köstler Helmut Rosemeyer

The scientific objective of the research reported in this manuscript was the synthesis of novel phosphoramidite building blocks for the preparation of lipophilic oligonucleotides. Reaction of inosine (4) with 4-oxopentyl-4-methylbenzoate (2c) in the presence of triethyl orthoformate and 4M HCl in 1,4-dioxane gave a diastereoisomeric mixture of the ketals 5. Subsequent 4,4'-dimethoxytritylation ...

Journal: :Dalton transactions 2016
Jordan R Lopez Lee Martin John D Wallis Hiroki Akutsu Yasuhiro Nakazawa Jun-Ichi Yamada Tomofumi Kadoya Simon J Coles Claire Wilson

We have synthesized the first examples of radical-cation salts of BEDT-TTF with chiral borate anions, [B(malate)2](-), prepared from either enantiopure or racemic bidentate malate ligands. In the former case only one of two diastereoisomers of the borate anion is incorporated, while for the hydrated racemic salt one racemic pair of borate anions containing a R and a S malate ligand is incorpora...

Journal: :Journal of the American Chemical Society 2012
Alexander P Pulis Varinder K Aggarwal

Enantioenriched secondary allylic carbamates have been deprotonated with sBuLi and reacted with boronic esters. In contrast to other electrophiles, high α-selectivity was observed and the boronate complexes were formed with almost complete retention of stereochemistry. The boronate complexes underwent a stereospecific 1,2-migration leading to tertiary allylic boronic esters with high er (>98:2)...

2014
Mei Wang Emily J. Carrell Zulfiqar Ali Bharathi Avula Amar G. Chittiboyina Cristina Avonto Jon F. Parcher Ikhlas A. Khan

The FDA has called for the detention of all imports of dietary supplements and bulk dietary ingredients that are or contain Mitragyna speciosa or the natural product kratom derived from this plant, due to the toxicity of kratom in multiple organ systems. The toxicity and psychoactive properties of this plant necessitate improved analytical techniques for the separation of the indole and oxindol...

2012
Fátima M P de Rezende Marilua A Moreira Rodrigo A Cormanich Matheus P Freitas

Four diastereoisomers of 2-fluorobicyclo[2.2.1]heptan-7-ols were computationally investigated by using quantum-chemical calculations, and their relative energies were analyzed on the basis of stereoelectronic interactions, particularly the presence or otherwise of the F∙∙∙HO intramolecular hydrogen bond in the syn-exo isomer. It was found through NBO and AIM analyses that such an interaction co...

Journal: :Organic & biomolecular chemistry 2010
Martina Würdemann Jens Christoffers

Spirocyclic carbazole- and acridine-lactams were prepared by Fischer-indole or Friedländer-quinoline synthesis starting from spirocyclic ketones with a lactam ring. All annulation products were obtained as mixtures of separable regioisomers, which differ only in the position of one methyl group. The starting materials were prepared from 2-pyrrolidone and 2-piperidone by a sequence of protection...

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