67061-80-7Relevant academic research and scientific papers
Stereochemistry of Ephedrine- and Pseudo-ephedrine-derived Oxazolidines and of Their N-Borane Adducts Determined by Nuclear Overhauser Effect Difference Spectroscopy
Santiesteban, Fernando,Grimaldo, Carlos,Contreras, Rosalinda,Wrackmeyer, Bernd
, p. 1486 - 1487 (1983)
Nuclear Overhauser effect difference spectra of 1,3-oxazolidines derived from ephedrine and pseudo-ephedrine and of their N-borane adducts allow the configuration at C(2) and N to be assigned.
Composition and stereochemistry of ephedrine alkaloids accumulation in Ephedra sinica Stapf
Krizevski, Raz,Bar, Einat,Shalit, Or,Sitrit, Yaron,Ben-Shabat, Shimon,Lewinsohn, Efraim
experimental part, p. 895 - 903 (2010/08/19)
Ephedra sinica Stapf (Ephedraceae) is a widely used Chinese medicinal plant (Chinese name: Ma Huang). The main active constituents of E. sinica are the unique and taxonomically restricted adrenergic agonists phenylpropylamino alkaloids, also known as ephedrine alkaloids: (1R,2S)-norephedrine (1S,2S)-norpseudoephedrine, (1R,2S)-ephedrine, (1S,2S)-pseudoephedrine, (1R,2S)-N-methylephedrine and (1S,2S)-N-methylpseudoephedrine. GC-MS analysis of freshly picked young E. sinica stems enabled the detection of 1-phenylpropane-1,2-dione and (S)-cathinone, the first two putative committed biosynthetic precursors to the ephedrine alkaloids. These metabolites are only present in young E. sinica stems and not in mature stems or roots. The related Ephedra foemina and Ephedra foliata also lack ephedrine alkaloids and their metabolic precursors in their aerial parts. A marked diversity in the ephedrine alkaloids content and stereochemical composition in 16 different E. sinica accessions growing under the same environmental conditions was revealed, indicating genetic control of these traits. The accessions can be classified into two groups according to the stereochemistry of the products accumulated: a group that displayed only 1R stereoisomers, and a group that displayed both 1S and 1R stereoisomers. (S)-cathinone reductase activities were detected in E. sinica stems capable of reducing (S)-cathinone to (1R,2S)-norephedrine and (1S,2S)-norpseudoephedrine in the presence of NADH. The proportion of the diastereoisomers formed varied according to the accession tested. A (1R,2S)-norephedrine N-methyltransferase capable of converting (1R,2S)-norephedrine to (1R,2S)-ephedrine in the presence of S-adenosylmethionine (SAM) was also detected in E. sinica stems. Our studies further support the notion that 1-phenylpropane-1,2-dione and (S)-cathinone are biosynthetic precursors of the ephedrine alkaloids in E. sinica stems and that the activity of (S)-cathinone reductases directs and determines the stereochemical branching of the pathway. Further methylations are likely due to N-methyltransferase activities.
Stability studies of oxazolidine-based compounds using 1H NMR spectroscopy
Moloney, Gerard P.,Iskander, Magdy N.,Craik, David J.
experimental part, p. 3362 - 3371 (2011/04/26)
A series of oxazolidine-based compounds with a variety of substituents in positions 2 and 3 was synthesized and their stability studied. Ring opened intermediates formed on addition of limiting amounts of D2O to oxazolidine solutions, as observ
Heterogeneous rhodium-catalyzed hydrogenation conditions for the highly effective synthesis of 1,3-oxazolidines from 1,2-amino alcohols and nitriles
Letinois, Stephane,Dumur, Jean-Christophe,Henin, Francoise,Muzart, Jacques
, p. 2327 - 2330 (2007/10/03)
A procedure easily to carried out for the synthesis of 1,3-oxazolidines in high yields using 1,2-amino alcohols, nitriles, an atmospheric pressure of hydrogen and catalytic quantities of rhodium on carbon powder is presented. This reaction probably involves the semi-hydrogenation of the nitrile followed by condensation with the amine alcohol. The process may constitute the key step in a two-step sequence for reducing a nitrile into the corresponding aldehyde.
