Methyl-ephedrine

Nagai s ephedrine was obtained from Ma-Huang and the same alkaloid, together with its stereoisomeride pseudoephednne ( -ephedrine), was isolated by Merck from the European species, E. helvetica C. A. Meyer. From commercial Ma-Huang Smith prepared two additional bases, 1-W-methylephedrine and nnr-d- -ephedrine. Nagai and Kanao added two more, viz., d-W-methyl- -ephedrine and Z-norephedrine, and... 

Der Komplex aus Lithiumalanat, (-)- bzw. (+)-N-Methyl-ephedrin und 3,5-Dime-thyl-phenol reduziert unverzweigte Alkyl-aryl-ketone in Ausbeuten iiber 90% und optischen Ausbeuten von 62 bis 80% zu den (+)-(R)- bzw. (-) -(S)-1 -Phenyl-alka-nolen . 

Among them, (1 R,2S)-l-phenyl-2-(l-pyrrolidinyl)propan-l-ol (46) was selected as a chiral modifier for further optimization. It is interesting to point out that N-methyl ephedrine was not a suitable chiral modifier for ketimine 5 (only 10% ee as shown in Table 1.2), but in the case of ketone 41, N-methyl ephedrine provided a respectable 53% ee, as shown in Table 1.5. 

Fan et al. [106] developed a high performance capillary electrophoresis method for the analysis of primaquine and its trifluoroacetyl derivative. The method is based on the mode of capillary-zone electrophoresis in the Bio-Rad HPE-100 capillary electrophoresis system effects of some factors in the electrophoretic conditions on the separation of primaquine and trifluoroacetyl primaquine were studied. Methyl ephedrine was used as the internal standard and the detection was carried out at 210 nm. A linear relationship was obtained between the ratio of peak area of sample and internal standard and corresponding concentration of sample. The relative standard deviations of migration time and the ratio of peak area of within-day and between-day for replicate injections were <0.6% and 5.0%, respectively. 

Metal alkoxides undergo alkoxide exchange with alcoholic compounds such as alcohols, hydro-xamic acids, and alkyl hydroperoxides. Alkyl hydroperoxides themselves do not epoxidize olefins. However, hydroperoxides coordinated to a metal ion are activated by coordination of the distal oxygen (O2) and undergo epoxidation (Scheme 1). When the olefin is an allylic alcohol, both hydroperoxide and olefin are coordinated to the metal ion and the epoxidation occurs swiftly in an intramolecular manner.22 Thus, the epoxidation of an allylic alcohol proceeds selectively in the presence of an isolated olefin.23,24 In this metal-mediated epoxidation of allylic alcohols, some alkoxide(s) (—OR) do not participate in the epoxidation. Therefore, if such bystander alkoxide(s) are replaced with optically active ones, the epoxidation is expected to be enantioselective. Indeed, Yamada et al.25 and Sharp less et al.26 independently reported the epoxidation of allylic alcohols using Mo02(acac)2 modified with V-methyl-ephedrine and VO (acac)2 modified with an optically active hydroxamic acid as the catalyst, respectively, albeit with modest enantioselectivity. 

Another chiral auxiliary for controlling the absolute stereochemistry in Mukaiyama aldol reactions of chiral silyl ketene acetals has been derived from TV-methyl ephedrine.18 This has been successfully applied to the enantioselec-tive synthesis of various natural products19 such as a-methyl-/ -hydroxy esters (ee 91-94%),18,20 a-methyl-/Miydroxy aldehydes (91% ee),21 a-hydrazino and a-amino acids (78-91% ee),22 a-methyl-d-oxoesters (72-75% ee),20b cis- and trans-l1-lactams (70-96% ee),23 and carbapenem antibiotics.24... 

With chiral enol species (/ )-silylketene acetal derived from (1 R,2S)-N-methyl ephedrine-O-propionate, both the aldehyde carbonyl and the ephedrine NMe2 group are expected to bind to TiCU, which usually chelates two electron-donating molecules to form ra-octahedral six-coordinated complexes.25 Conformational freedom is therefore reduced, and the C-C bond formation occurs on the six-coordinated metal in a highly stereoselective manner.18... 

Certain erythro-2-wamo alcohols such as ( )-ephedrine 150, ( )-A -methyl-ephedrine 151 and ( )-conhydrine 153 are synthesized with complete stereochemical control by the catalytic hydrogenation of the corresponding 4,5-disubstituted 2(3/i)-oxazolone derivatives 22 and 27, followed by ring opening (Fig. 5.37). ... 

Auf ahnliche Weise erhalt man (ii)-Aminosauren mit (// ,2S )-N-Methyl-ephedrin als chiralem Hilfsalkohol2 ... 

R)-( - )-3-Benzyloxy-2-methylpropionaldehyde (2), obtained from N-methyl-ephedrine, reacts with the ketene f-butylthio trialkylsilyl acetal 3 in CH2C12 in the presence of TiCl4 to give 4 in >99% de. Use of BF3 etherate as the Lewis acid catalyst results in three stereoisomers.13... 

Much work related to the development of a catalytic, enantioselective version of the Baylis-Hillman-Reaction by the use of chiral bases has been published. Only low enantiomeric excesses were obtained when brucin, N-methylprolinol, N-methyl-ephedrine and nicotine... 

Shortly after this initial success, the isolation of optically active propargyl alcohols in up to 99 % ee could be effected by the use of stoichiometric amounts of (-i-)-N-methyl ephedrine (1) (Eq. 7). A wide range of aldehydes and acetylenes participate in this addition reaction affording the product alcohols in generally high yields, especially when using aldehydes that are Ca-branched (Eq. 8). Of additional importance, the reaction can be performed with functionalized alkynes, which... 

Metab-O-Lite Metabolift Up Your Gas Truckers Luv It Yellow Jackets Methyl ephedrine Myocardial infarction Hepatitis Stroke Seizures Psychosis Death... 

Lithium aluminum hydride-1-)-N-Methyl-ephedrine, 238 Lithium arenesulfonates, 69 Lithium benzeneselenOlate, 238-239 Lithium bis(ethylenedioxyboryl)methide,... 

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