SYNTHESIS OF ALPHA-D-GLUCOPYRANURONATE 1-PHOSPHATE AND BETA-D-GLUCOPYRANURONATE 1-PHOSPHATE AND ALPHA-D-GLUCOPYRANURONATE 1-FLUORIDE - INTERMEDIATES IN THE SYNTHESIS OF D-GLUCURONIC ACID FROM STARCH

The title uronates were prepared by 2,2,6,6-tetramethyl-1-piperidinylo xy (TEMPO) catalysed sodium hypochlorite oxidation of alpha- and beta- D-glucopyranosyl phosphate(alpha-/beta-Glc-1-P) and alpha-D-glucopyran osyl fluoride (alpha-Glc-1-F). Quantitative recovery of the TEMPO cata lyst was achieved by azeotropic distillation of a small part of the re action mixture, Also, a heterogeneous catalyst system was prepared by immobilisation of 4-oxo-tetramethyl-1-piperidinyloxy (OTEMPO) on amino -functionalized silica. The protected uronates were hydrolysed to yiel d D-glucuronate. Since alpha- and beta-Glc-1-P and alpha-Glc-1-F can b e obtained from starch in one step, D-glucuronic acid is now available from starch in a convenient three-step sequence. (C) 1997 Elsevier Sc ience Ltd.