STUDIES ON 3-EPIMERIC 2-HEXULOSE PHENYLOSAZONES. STRUCTURE AND ANOMERIC CONFIGURATION OF THE 3,6-ANHYDRO-OSAZONE DERIVATIVES OBTAINED FROM D-arabino- AND D-ribo-2-HEXULOSE PHENYLOSAZONE

Article abstract of DOI:10.1016/S0008-6215(00)85574-3

Dehydration of the 3-epimeric 2-hexulose phenylosazones D-arabino-hexulose phenylosazone or D-ribo-hexulose phenylosazone afforded 3,6-anhydro-D-ribo-hexulose phenylosazone (4) as the preponderant isomer from both.The identity of 4 was obtained by t.l.c., and by acylation followed by comparison of the products.Prolonged acetylation with acetic anhydride-pyridine, or by refluxing with acetic anhydride, afforded the same N-acetyldi-O-acetyl derivative.Refluxing 4 with copper sulfate, or the osotriazole with 20percent methanolic sulfuric acid, afforded the C-nucleoside analog, namely, 4-β-D-erythrofuranosyl-2-phenyl-1,2,3-osotriazole (7).The anomeric configurations of 4 and 7 were ascertained from the n.m.r. spectra of their isopropylidene derivatives.The mechanism of the dehydrative cyclization process and the mass spectra of two compounds were discussed.