منابع مشابه
Are lignins optically active?
The accepted derivation of lignins from non(enzymatically)-controlled radical coupling reactions has been recently challenged, and it is relevant to ascertain unequivocally whether lignins are or are not (as normally assumed) optically active. Two approaches were used. First, DFRC (derivatization followed by reductive cleavage) dimers derived from beta-5- and beta-beta-units in pine lignins, wh...
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The circularly polarized reflection of nature is due to their distinct azimuthally twisted or helical character in the nanostructure of the surface films. Although many chiral inorganic powders have been successfully synthesised, the artificial synthesis of chiral inorganic films is rare. Herein, we reported a facile synthetic route for the growth of monolayered chiral film on the quaternary am...
متن کاملMolten salt-supported polycondensation of optically active diacid monomers with an aromatic thiazole-bearing diamine using microwave irradiation
Microwave heating was used to prepare optically active thiazole-bearing poly(amide-imide)s. Polymerization reactions were carried out in the molten tetrabutylammonium bromide as a green molten salt medium and triphenyl phosphite as the homogenizer. Structural elucidation of the compounds was performed by Fourier transform infrared and NMR spectroscopic data and elemental analysis results. The p...
متن کاملOptically active diaryl tetrahydroisoquinoline derivatives.
In (1R,3S)-6,7-dimethoxy-3-(methoxydiphenylmethyl)-1-phenyl-1,2,3,4-tetrahydroisoquinoline, C(31)H(31)NO(3), (I), and (1R,3S)-2-benzyl-3-[diphenyl(trimethylsiloxy)methyl]-6,7-dimethoxy-1-phenyl-1,2,3,4-tetrahydroisoquinoline, C(40)H(43)NO(3)Si, (II), the absolute configurations have been confirmed to be R and S at the isoquinoline 1- and 3-positions, respectively, by NMR spectroscopy experiment...
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D-configured poly(D-lactic acid) (D-PLA) and poly(D-2-hydroxy-3-methylbutanoic acid) (D-P2H3MB) crystallized separately into their homo-crystallites when crystallized by precipitation or solvent evaporation, whereas incorporation of L-configured poly(L-2-hydroxybutanoic acid) (L-P2HB) in D-configured D-PLA and D-P2H3MB induced co-crystallization or ternary stereocomplex formation between D-conf...
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ژورنال
عنوان ژورنال: Nature
سال: 1932
ISSN: 0028-0836,1476-4687
DOI: 10.1038/130368b0