3-C-hydroxymethyl-D-riburonic acid. Synthesis of the branched-chain uronic acid and comparison with a carbohydrate component of a naturally occurring bilirubin conjugate

A novel carbohydrate has previously been isolated from human bile as a complex glycoside of bilirubin 1]. This compound has been tentatively identified as 3-C-hydroxymethyl-D -riburonic acid. To test this structural assignment the proposed branched-chain uronic acid was synthesized. Gas chromatographic and mass spectrometric comparison of the natural and synthetic materials indicated that the proposed structure, 3-C-hydroxymethyl-D-riburonic acid, did not apply to thc natural product.