INVESTIGADORES
VARELA Oscar Jose
artículos
Título:
A convenient synthesis of hexulosonic acids by IBX mediated oxidation of D-glucono-1,5-lactone derivatives
Autor/es:
ADRIANA A. KOLENDER; SOL C. PARAJÓN PUENZO; VARELA, OSCAR
Revista:
ARKIVOC - ONLINE JOURNAL OF ORGANIC CHEMISTRY
Editorial:
ARKAT USA INC
Referencias:
Año: 2011 vol. 7 p. 237 - 244
ISSN:
1551-7004
Resumen:
The oxidation of the free hydroxyl group of methyl 3,4:5,6-di-O-isopropylidene-D-gluconate 2 or its 2,3:5,6-di-O-isopropylidene analogue 3, the products of acetonation of D-glucono-1,5-lactone 1, has been attempted by alternative procedures. The oxidation of OH-2 in 2, or OH-4 in 3, with o-iodoxybenzoic acid (IBX) took place to afford the respective 2-keto 4 and 4-keto 7 derivatives in almost quantitative yields. In contrast, the oxidations with pyridinium dichromate were unsuccessful, and those using dimethylsulfoxide-acetic anhydride afforded low yields of 4 or 7. Selective removal of the isopropylidene groups in 4 or 7 with 88% aqueous acetic acid afforded, respectively, the methyl esters 5 or 8; whereas treatment with aqueous trifluoroacetic acid led to the free hexulosonic acids 6 or 9. The tautomeric preferences for the oxidation products 4 and 7, and their derivatives, have been established by 13C NMR spectroscopy.
