Correlations of Nuclear Magnetic Resonance and Optical Rotatory Dispersion Spectra for Establishing the Absolute Configurational Assignment of Cobalt(III)-Chelated Optically Active Triethylenetetramine Homolog-α-Amino Acid Adducts

The conversion of (+)-catechin tetramethyl ether into (-)-2-chloro-5,7,3',4'-tetramethoxyisoflavan is shown to proceed by 1,2-migration of the 2-aryl group with inversion of configuration at the 3-position of the flavan nucleus (the migration terminus). The chloroisoflavan was converted into (+)-cis-2-acetoxy-5,7,3',4'-tetramethoxyisoflavan and reduction of this gave (+)-2-(3,4-dimethoxyphenyl)-3-(2,4,6-trimethoxyphenyl)propan-1-ol. This was converted into the corresponding (+)-propane which gave (-)-methylsuccinic acid on ozonolysis. The (+)-propane therefore possesses the (8)-configuration corresponding to the (S)-configuration of the (+)-2,3-diarylpropan-1-ol and the (3s)-configuration of the (+)-cis-2-acetoxy-isoflavan. (+)-cis-2-Ethoxy- and (+)-cis-2-methoxy-5,7,3',4'-tetramethoxyisoflavan have been converted into the related (+)-1-alkoxy-2,3-diarylpropanes. Chlorination of the phloroglucinol nucleus in (+)-catechin tetramethyl ether may occur during reaction with phosphorus pentachloride and is shown to lead to 2,6-dichloro-5,7,3',4'-tetramethoxyisoflavan. Racemic cis- and laevorotatory and racemic trans-2-acetoxy-5,7,3',4'-tetramethoxyisoflavan have been prepared. Nuclear magnetic resonance and optical rotatory dispersion data for a number of isoflavans are reported. The absolute configurations of pterocarpin, homopterocarpin, and pisatin are inferred.

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THE β-D -CONFIGURATION OF THE RIBOSYL NICOTINAMIDE PORTION OF DIPHOSPHOPYRIDINE NUCLEOTIDE

Canadian Journal of Chemistry ◽

10.1139/v63-127 ◽

1963 ◽

Vol 41 (4) ◽

pp. 889-897 ◽

Cited By ~ 46

Author(s):

R. U. Lemieux ◽

J. W. Lown

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Dispersion Curves ◽

Optical Rotatory Dispersion ◽

Rotatory Dispersion ◽

Optical Rotatory ◽

Anomeric Configuration ◽

Anomeric Center ◽

Nuclear Magnetic

The configurations of the anomeric N-(tetra-O-acetyl-D-glucopyranosyl)-3-carboxamido-pyridium bromides were established by nuclear magnetic resonance (n.m.r.) spectroscopy. The β-D-anomer was found to undergo deacetylation without anomerization. This compound on oxidation with periodate has been shown (M. Viscontini and E. Hürzeler-Jucker. Helv. Chim. Acta, 39, 1620 (1956)) to yield a different product than did a synthetic N- (D-ribo-furanosyl)-3-carboxamidopyridinium chloride. Therefore, the anomeric configuration of the latter compound must be is α-D. Since its anomer was used (N. A. Hughes, G. W. Kenner, and A. Todd. J. Chem. Soc. 3733 (1957)) to synthesize diphosphopyridine nucleotide (DPN), the configuration of the anomeric center in this portion of the coenzyme must be β-D. Optical rotatory dispersion curves are reported for DPN, its component nucleotides, and the above-mentioned D-glucosides.

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