DL-Ephedrine

C10H15NO N-hydroxyethyl-a-methyl benzyl amine 1331-41-5 515.82 45.406 2 20390 C10H16NO4P DL-ephedrine phosphate (ester) 7234-09-5 601.15 53.683 1.2... 

While this approach has been applied primarily to nucleophilic reactions of carbonyl compounds, it can also be used to determine the primary direction of hydrogenation since adsorption on a catalyst surface is preferred from the less hindered side of the carbonyl group. The synthesis of dl ephedrine (20) was accomplished by the hydrogenation of the amino ketone, 19, one enantiomer of which is depicted in Eqn. 14.17.5 xhe hydrogen bond to the carbonyl oxygen helps fix the conformation with hydrogenation taking place from the side of the... 

The ephedrine synthesis described by Manske and Johnson (74) and by Skita and Keil (77) in 1929 is founded on a different reaction. If a mixture of o -phenylpropane-a,/S-dione and methylamine, in absolute alcohol is hydrogenated catalytically in the presence of platinum oxide (Manske) or colloidal platinum (Skita), dl-ephedrine, with a little dJr -ephedrine is obtained. The reaction has been further elaborated by Coles, Manske, and Johnson (76), by Skita, Keil and coworkers (78, 79, 262, 263) and by Couturier (265). Manske and Johnson (75) synthesized some ephedrine homologs and resolved racemic ephedrine by means of d-and f-mandelic acid. The pure I form of this acid is prepared easily with the aid of natural ephedrine, as confirmed by Jarowski and Hartung (268). 

According to Chen, Wu, and Henriksen, norephedrines have a strong action, comparable to that of the ephedrines nor-d- -ephedrine has a weaker action than I or dl-ephedrine, but stronger than d- f -ephedrine. 

A soln. of NaBH4 in methanol added at 20-30° during 1 hr. to a stirred soln. of bis-[2-(N-methyl-a-methylphenacylamino) ethyl] disulfide in the same solvent, and stirring continued 1 hr. -> dl-fhreo-bis-[2-(N-methyl-a-methyl- -hydroxy-phenethylamino) ethyl] disulfide (Y 84%) dissolved in ether, added during 1 hr. to stirred ethereal LiAlH4, and refluxed 1 hr. on a water bath -> N-(2-mercapto-ethyl)-dl- / -ephedrine (Y 92%). H. Nishimura, O. Yamauchi, and H. Takamatsu, Ghem. Pharm. Bull. 12, 1004 (1964). 

Notably, pseudoephedrine is a diastereomer of ephedrine and considerably racemic ephedrine (dl-ephedrine) has not been found naturally, however, it is prepared synthetically and is inactive for commercial purposes. Ephedrine and pseudoephedrine are completely stable compounds under changing temperature conditions, but they are quite unstable when exposed to sunlight or in the presence of oxygen pressure [2]. The unique molecular structure of ephedrine causes its different stereoisomers to be valuable for pharmaceutical applications such as nasal decongestant, pupil dilator, bronchodilator, and central nervous system stimulant. Ephedrine is a sympathomimetic substance and the principle mechanism of ephedrine activity is its influence, by enhancing the activity of noradren-alin, on post-synaptic a- and (3-receptors in the nervous system. Stimulation of a 1-adrenergic receptors produces contraction of vascular smooth muscle. 

Likewise, record the second derivative spectra of the four standard pseudo-ephedrine hydrochloride solutions and record the peak heights DL at 258-259 nm plot the results against concentration and confirm that a straight line is obtained. 

Although initially available as an injectable solution for the treatment of obesity, D-metham-phetamine hydrochloride is currently available as conventional and prolonged release tablets. Illicit methamphetamine is synthesized from the precursors phenylacetone and iV -methylformamide (dl mixture) or alternatively from ephedrine or pseudoephedrine by red phosphorus/acid reduction. 

Wong, C. H. and Wang K. T. (1978) Mutual resolution of (+/-)ephedrine and Z-DL-amino acid induced by seeding chiral salt, Tetrahedron Lett. 40, 3813-3816. 

The use of CDs with bile salt micelles has been also successful for enantiomer separations. For example, Dns-DL-AAs, baclofen and its analogs, mephenytoin and fenoldopam, naphthalene-2,3-dicarboxaldehyde derivatized dl-AAs (CBI-dl-AAs), diclofensine, ephedrine, nadolol, and other j8-blockers, and binaphthyl-related compounds were enantioseparated by CD-MEKC with bile salts. 

Ephedrine (l-j Epichlorhydrin (a-) Epidichlorohydrin (a-) Erythritol (dl-j tetranitrate Ethane... 

The j3-hydroxyphenethylamine synephrine (198) appears to arise in Citrus from tyrosine via tyramine and iV-methyltyramine. ° Normacromerine (199) and macromerine (200) are found in the cactus Coryphantha macromeris var. runyoniO Their genesis has also been studied.Specific incorporations of DL-[3- C]tyrosine, [l- C]tyramine, DL-[2- " C]dopa, and [l- CJdopamine into normacromerine established a pattern of biosynthesis similar to that of the other cactus alkaloids and again a C6-C2 unit is implicated. [This contrasts with the biosynthesis of the superficially similar base ephedrine (185), discussed above.]... 

N-Bz-Leu anilide N-Bz-N-methyl-Leu N-(2-Bz-1 -methylvinyl) -Leu Z-Erythro-/3-methyl-Leu 2i-Erythro-/3-methyl-D-Leu Z-Erythro-/3-methyl-D-Leu (- -)-ephedrine salt Z-Leu Z-D-Leu Z-Leu amide Z-DL-Leu amide Z-Leu-NHBzl Z-Leu-NHCHjCHjOH Z-Leu(-f-) ephedrine salt... 

Z-Phe Boc-hydrazide Z-Di Phe-NHCHjCN Z-Phe-NHC,Hii Z-DL-Phe-OCHjCN Z-Phe-0-2,2-diphenylethyl Z-Phe-N,N -diphenyl hydrazide Z-D-Phe (+) ephedrine salt N"-2i-Phe- -nitroanilide... 

Z-DL-Val-OBhae Z-D-Val (+) ephedrine salt N-Z-Val 4-(methyl-sulfonyl)phenyl ester... 

Kaddoumi, A. Nakashima, M.N. Nakashima, K. Fluorometric determination of DL-fenfluramine, DL-norfenfluramine and phentermine in plasma by achiral and chiral high-performance liquid chromatography, J.Chromatogr.B, 2001, 763, 79-90. [fluorescence detection derivatization human rat LOD 10 nM ephedrine norephedrine]... 

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