- Comparison of diffusion coefficients for matched pairs of macrocyclic and linear molecules over a drug-like molecular weight range
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The diffusion coefficients of a series of closely matched pairs of macrocyclic and linear molecules have been compared using NMR spectroscopy. The macrocyclic series was designed both to overlap with and extend beyond the molecular weight range typically employed for drug-like molecules. The linear molecules each represent a carbogenic fission of their macrocyclic counterparts, designed to minimize differences in functionality and physicochemical properties. Each series of molecules was prepared using copper catalyzed azide-alkyne cycloaddition (CuAAC) reactions conducted in a flow using a copper tube. The macrocyclic series exhibited consistently higher diffusion across the entire molecular weight range studied. The fold difference in diffusion coefficients between the macrocyclic and linear analogues appeared to be independent of either solvent viscosity or dielectric environment.
- Bogdan, Andrew R.,Davies, Nichola L.,James, Keith
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supporting information; experimental part
p. 7727 - 7733
(2011/12/03)
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- A PROCESS FOR THE PREPARATION OF R-(-)-N, α-DIMETHYLPHENETHYLAMINE (LEVMETAMFETAMINE) OR S-(+)-N, α-DIMETHYLPHENETHYLAMINE (METHAMPHETAMINE) FROM d-EPHEDRINE OR L-EPHEDRINE RESPECTIVELY
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A process for synthesis of R-(-)-N, α -Dimethylphenethylamine (Levmetamfetamine, formula I), or S-(+)-N, α - Dimethyl phenethylamine (Methamphetamine, formula II ), from d-ephedrine of formula III or l-ephedrine formula IV, the process comprising the steps of (a) acylating the d- or l-ephedrine base of formula III or formula IV with an acylating agent to make a reaction mixture containing a N- acylated ephedrines of formula V or formula VI ; (b) deoxygenation of N-acylated ephedrines to make the compound of the formula VII or Formula VIII by using Raney Nickel catalyst ; and (c) acid hydrolysis of the above deoxygenated products to get the levmetamfetamine or methamphetamine.
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Page/Page column 18
(2008/06/13)
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- MISE EN EVIDENCE PAR RMN-(1)H ET -(13)C D'ISOMERISME Z/E ET D'EQUILIBRE CONFORMATIONNEL SUR UNE SERIE DE DERIVES MONO- ET DIACETYLES DE 2-ALKYLAMINO-1-PHENYLPROPAN-1-OLS
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(1)H- and (13)C NMR studies of mono- and diacetylated-erythro- and threo-2-alkylamino-1-phenylpropan-1-ols, C6H5CHOHCHNHRCH3 (R = H, CH3, C2H5 AND i-C3H7) show that the series exhibit Z/E isomerism about the C-N amide bond.The Z/E ratio increases in the monoacetylated series CH3 1-C2 and N-C2 bonds.In the Z configuration, the conformer Z-s-syn where the proton H-2 is syn with the N-alkyl substituent predominates.
- Tytgat, D.,Gelbcke, M.
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p. 479 - 490
(2007/10/02)
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- Reactions of (-)-Ephedrine, (+)-Norpseudoephedrine and Derivatives with N,N-Dimethylacetamid-dimethylacetal and N,N-Dimethylformamid-dimethylacetal
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The reactivity of (-)-ephedrine (2) and (+)-norpseudoephedrine (3) towards the amid-acetals 1 a/b has been studied.Both 2 and 3 were acetylated resp. formylated at first at the amino group.Nevertheless, derivatives of 2 and 3 possessing a trisubstituted amino group react with 1 a in a sigmatropic rearrangement to ortho substituted dimethylcarbamoylmethyl derivatives.By subsequent reduction with lithiumaluminiumhydride the aromatic compounds 8, 13, and 18 with two aminoethyl groups are easily available.In contrast to these results 1 b did not furnish any rearrangement products. Keywords. (-)-Ephedrine; (+)-Norpseudoephedrine; N,N-Dimethylacetamid-dimethylacetal; N,N-Dimethylformamid-dimethylacetal; Sympathomimetic effects; Sigmatropic rearrangements.
- Koehl, M,Spreitzer, H.,Fleischhacker, W.
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p. 911 - 918
(2007/10/02)
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