Synthesis of Methyl 4-O-methyl-β-D-ribo-hex-3-ulopyranoside-1-13C and Methyl 4-O-methyl-β-D-ribo-hex-3-ulopyranoside-3-13C as Fragment Analogues of Oxidized Cellulose Units

Model compounds of oxidized anhydroglucose units in cellulosic materials, carrying 13C isotopic labels at specific positions, have been synthesized starting from commercially available 1-13C-D-glucose (14.7%) and 3-13C-Dglucose (6.3%), respectively, over 10 linear steps. To ensure high yields, the synthetic route was optimized with non-labeled material beforehand. The labeled compounds are used in studies of chromophore formation, yellowing, brightness reversion and aging of cellulosics. Keywords: Cellulose, aging, yellowing, brightness reversion, isotopic labeling, 3-keto-glucose