ISSN:
0075-4617
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
Reactions of Enolic Sugar Derivatives, X1). - Allylic Actiovation in 4- and 3-O-Tosylates of Hex-5-enopyranosidesMethyl-2,4-Di-O-acetyl-6-deoxy-3-O-tosyl-β-D-xylo- and α-L-arabino-hex-5-enopyranoside )2 and 5 as well as the corresponding 4-O-tosylates 8 and 11 were synthesized. The compounds react highly selectively under mild conditions. When treated with sodium methoxide, 2 yields the 3,4-anhydro compound 3 selectively via detosylation and deacetylation. Under the same conditions 5 and 8 yield the isomeric 3,4-anhydro compound 9 in analogous manner; 11 is converted into 3-hydroxy-6-methyl-4H-pyran-4-one (allomaltol, 12). In aqueous pyridine 8 is solvolyzed with inversion at C-4. On vinylogous substitution with sodium iodide, compounds 8 and 11 yield the methyl-2-3,-di-O-acetyl-4,6-dideoxy-6-iodo-α-L-threo-hex-4-enopyranoside (20).
Notes:
Methyl-2,4-di-O-acetyl-6-desoxy-3-O-tosyl-β-D-xylo-und α-L-arabino-hex-5-enopyranosid (2 bzw. 5) sowie die entsprechenden 4-O-Tosylverbindungen 8 und 11 wurden dargestellt. Die Verbindungen setzen sich unter milden Bedingungen mit hoher Selektivität um. Das Hex-5-enopyranosid 2 reagiert mit Natriummethylat unter Enttosylierung und Entacetylierung selektiv zu der 3,4-Anhydroverbindung 3 Aus 5 und 8 entsteht entsprechend die isomere 3,4-Anhydroverbindung 9, aus 11das 3-Hydroxy-6methyl-4-H-pyran-4-on (Allomaltol, 12). In wasserhaltigem Pyridin solvolysiert die Tosylgruppe von 8 glatt unter Inversion an C-4. Die 4-O-Tosylverbindungen 8 und 11 bilden durch vinyloge Substitution mit Natriumjodid Methyl-2,-3-di-O-acetyl-4-,6-didesoxy-6-jod-α-L-threo-hex-4-enopyranosid (20).
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.197419741019
