Application of sugar-containing biomass: one-step synthesis of 2-furylglyoxylic acid and its derivatives from a vitamin C precursor

We developed a novel pathway for preparing the high-value pharmaceutical intermediate 2-furylglyoxylic acid (2FGA) from 2-keto-l-gulonic acid (2KGA), a bio-based sugar-acid monomer and precursor of vitamin C, via dehydration. 100 g L⁻¹ methyl 2-keto-l-gulonicate (Me-2KGA) was transformed into methyl 2-furylglyoxylicate (Me-2FGA) with a maximum yield of 79.4%, competing with the yields obtained via traditional commercial synthesis methods. Subsequently, characterisation methods and theoretical calculations were employed; it was confirmed that natural 2KGA, with a 2,5-cyclic configuration, was esterified initially, it then underwent a transformation to an opened intermediate which further recyclized in a 3,6-cyclic configuration via removing one molecule of water, and this was finally dehydrated to Me-2FGA. This study offers novel insight into the flexibility and versatility of furan-based compounds.