ISSN:
0941-1216
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Synthesis and Conformational Analysis of Pyranophanones and Pyrylophanium Compounds with Intraannular SubstituentsThe synthesis of [3.3]dithiapyranophanone 6 and 11 is accomplished by use of the two-components-dilution-principle. Pyrolysis of their bis(sulfones) 7 and 12 gives the [2.2]pyranophanones 8, 9 and 13. Under preservation of conformation the intraannular carbonyl-function is used for the synthesis of methylpyranophanoles 14, 16 and 17. The synthesis of pyrylophanium compounds 15 and 18 is possible by elimination in trifluoroacetic acid.6 exhibits anti-conformation within its crystal-structure and like 7 reveals temperature-dependent behavior in solution. Using 6 as an example, a combination of 13C-NMR-spectroscopy, forcefield-calculation and computer-simulation is applied for the first time to give evidence for molecular-dynamic processes of cyclophanes.8 and 9 are the syn- and anti-conformers of the desired product, as shown by X-ray structural analysis. 13 reveals anti-conformation within its crystal structure as well as in solution. The conformational analysis of other new phanes described here is based on the 1H-NMR-spectra of these pyrolysis products.As expected the intraannular substituents of Pyrylophanium-lons 15 and 18 show the characteristic upfield-shift within their 1H-NMR-spectra.
Additional Material:
13 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/prac.19933350603
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