3853-88-1Relevant academic research and scientific papers
Resolution of (±)-Bicyclo[2.2.1]hept-5-ene-trans-2,3-dicarboxylic Acid: Crystal Structure of Its Cinchoninium Salt
Jiménez, Lissette,González, Teresa,Brice?o, Alexander,Agrifoglio, Giuseppe,Pastrán, Jesús,Dorta, Romano
, p. 203 - 207 (2016/05/02)
Abstract: Single crystals of (+)-cinchoninium (+)-bicyclo[2.2.1]hept-5-ene-trans-2-carboxyl-3-carboxylate (S,S)-2 were obtained upon resolution of racemic (±)-bicyclo[2.2.1]hept-5-ene-trans-2,3-dicarboxylic acid rac-1 with (+)-cinchonine. An X ray diffraction analysis established the most important secondary interactions between the ions that are deemed responsible for the diastereomeric separation process. From (S,S)-2 enantiomerically pure (+)-bicyclo[2.2.1]hept-5-ene-trans-2,3-dicarboxylic acid (S,S)-1 was isolated in 72 % yield. Graphical Abstract: An X-ray diffraction analysis of (+)-cinchoninium (+)-bicyclo[2.2.1]hept-5-ene-trans-2-carboxyl-3-carboxylate (S,S)-2 established the most important secondary interactions between the ions that are deemed responsible for the diastereomeric separation process.[Figure not available: see fulltext.]
Chiral rhodium-diphosphine catalyst capable of catalytic reduction of a tetramisole precursor to give a significant excess of the desired S-(-)isomer, levamisole
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, (2008/06/13)
A soluble, chiral, rhodium-containing catalyst which permits the catalytic reduction of prochiral 3-acyl-1-(2-alkoxyethyl)-4-phenyl-2-imidazolinones to chiral 3-acylimidazolidinones with a substantial excess of the desired S optical isomer. The 3-acylimidazolidinones may in turn be substantially converted to levamisole, and S isomer of tetramisole. The resolution of tetramisole to remove the R isomer is thus avoided.
