27270-80-0Relevant academic research and scientific papers
An efficient synthesis of aziridines from ephedrines
Cruz, Alejandro,Padilla-Martinez, Itzia Irene,Garcia-Baez, Efren V.
experimental part, p. 909 - 913 (2010/08/19)
The reaction of chlorodeoxyephedrine hydrochlorides with one, two, and three molar equivalents of base was studied. Isochlorodeoxypseudoepherines were identified and assigned by 1H and 13C NMR data as intermediate compounds in the formation of cis-aziridines. Erythro and threo ephedrinethylethers were isolated as new compounds and analyzed by spectroscopic data. In addition, the erythro isomer was studied by X-ray diffraction.
Chlorination reactions of ephedrines revisited. Stereochemistry and functional groups effect on the reaction mechanisms
Flores-Parra, Angelina,Suarez-Moreno, Patricia,Sanchez-Ruiz, Sonia A.,Tlahuextl, Margarita,Jaen-Gaspar, Javier,Tlahuext, Hugo,Salas-Coronado, Raul,Cruz, Alejandro,Noeth, Heinrich,Contreras, Rosalinda
, p. 1661 - 1671 (2007/10/03)
The stereochemistry of the chlorination reactions with SOCl2 of free ephedrine and pseudoephedrine and their hydrochlorides, examides and sulfonamides was analyzed. Chlorination of free and hydrochloride erythro isomers occurs with 100% inversion of configuration at C-1 (S(N)2 mechanism). Chlorination of examides and sulfonamides of erythro isomers occurs with retention of the configuration at C-1, (S(N)i mechanism). Chlorination reactions in all three isomers and derivatives hydrochlorides, examides or sulfonamides gave the same ratio of erythro (40%) and three isomers (60%) (S(N)1 mechanism). Treatment of the isomeric mixture of the chlorodeoxyephedrine and chlorodeoxypseudoephedrine hydrochloride in DMSO with HCl changes the isomeric ratio, increasing the erythro isomer content (65%). Using the erythro ethanolamines it is possible to arrive stereoselectively at the erythro chloroamines if the compound is previously tosylated or converted to the amide, or to the three chloroamines if the compound is directly chlorinated with SOCl2.
Liquid Chromatographic Determination of the Enantiomeric Composition of Methamphetamine Prepared from Ephedrine and Pseudoephedrine
Noggle, F. Taylor,DeRuiter, Jack,Clark, C. Randall
, p. 1643 - 1648 (2007/10/02)
Determination of the stereochemical makeup of forensic samples can provide information about the source of the sample and a basis for intersample comparisons.The clandestine synthesis of methamphetamine and related amines continues to be a major source of these drugs of abuse.Most synthetic methods employ carbon-nitrogen bond formation and produce a racemic mixture; however, the individual enantiomers of ephedrine and pseudoephedrine contain the structural components of methamphetamine in chiral form.This paper will focus on the stereochemical course of the synthesis of methamphetamine via hydrogenolysis of the benzylic hydroxyl group in ephedrine and pseudoephedrine.The configurations of these amines were determined by liquid chromatography on an achiral C18 stationary phase following precolumn derivatization with 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl isothiocyanate.
