ISSN:
0947-3440
Schlagwort(e):
D-Fructofuranoses
;
Benzoates
;
Pivaloates
;
1,2- and 2,3-Cyclocarbamates
;
keto-D-Fructose pentabenzoates
;
α-D-Fructopyranoses
;
1,2-Cycloacetals
;
Chemistry
;
Organic Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
Acylations of D-fructose are complicated at several levels. The product distribution is determined not only by the rate of equilibration of the crystalline β-p-form in pyridine to the α-p, β-f, and α-f-tautomers, but also by the distribution of these forms at a given temperature, as well as their individual hydroxyl group. A detailed study of these parameters resulted in the elaboration of new or improved procedures for the practical, straightforward preparation of either acyclic, furanoid, or pyranoid benzoyl and pivaloyl derivatives, as well as cyclocarbamates with 1,2-spiro-annelated and 2,3-bridging oxazolidinone rings. Accordingly, a variety of simple, tautomerically fixed fructose derivatives, most notably those of the α-p, α-f and β-f forms, are now easily accessible for exploitation as versatile enantiopure building blocks. The structures, anomeric configurations and conformations of the various products obtained were determined on the basis of their 1H and 13C NMR data. The furanoid cases required the support of two X-ray structures: the pentabenzoyl-α-D-fructofuranose (9) which has an E2 conformation, and the 2,3-cyclocarbamate 25, in which the β-furanose ring adopts a 5E geometry.
Zusätzliches Material:
2 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/jlac.1995199512292
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