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Diastereoisomerization and X-ray Crystal Structure of meso-di-(2H-Chromene-2-yl) Ether

L. Lončar ; Departmeni of Organic Chemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev trg 20, 41000 Zagreb,. Croatia
M. Mintas ; Departmeni of Organic Chemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev trg 20, 41000 Zagreb,. Croatia
A. Hergold-Brundić ; Laboratory of General and Inorganic Chemistry, Faculty of Science, Zvonimirova 8, 41000 Zagreb, Croatia
A. Nagl ; Laboratory of General and Inorganic Chemistry, Faculty of Science, Zvonimirova 8, 41000 Zagreb, Croatia
T. Trotsch ; Institute of Organic Chemistry, University of Regensburg, Universitatsstr. 31, D-93040 Regensburg, Germany
A. Mannschreck ; Institute of Organic Chemistry, University of Regensburg, Universitatsstr. 31, D-93040 Regensburg, Germany

Sažetak

It was shown by X-ray crystal structure analysis that di-(2Hchromene-
2-yl)-ether (1) exists in the meso-form, i.e. as (2S, 2'R)-1. The Xray
structural data indicate, also, that geometries of the two 2H-1-benzopyran parts, of which the skeleton of 1 consists, are not identical, that is the molecule is pseudosymmetrical. The meso-l undergoes thermally induced electrocyclic ring opening and reclosure. Thus, meso-1 equilibrates with enantiomers (2S, 2'S)-1 and (2R, 2'R)-1, as conf'irmed by their lH_ NMR spectra after preparative separation of stereoisomers using liquid chromatography on triacetylcellulose.

Ključne riječi

Hrčak ID:

176562

URI

https://hrcak.srce.hr/176562

Datum izdavanja:

1.2.1995.

Posjeta: 774 *