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Synlett 2010(4): 583-586  
DOI: 10.1055/s-0029-1219356
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

A Simple Synthesis of C-8 Modified 2-Keto-3-deoxy-d-manno-octulosonic Acid (KDO) Derivatives

Renee Winzar, Jessica Philips, Milton J. Kiefel*
Institute for Glycomics, Griffith University, Gold Coast Campus, Queensland 4222, Australia
Fax: +61(7)55528098; e-Mail: m.kiefel@griffith.edu.au;
Further Information

Publication History

Received 18 December 2009
Publication Date:
02 February 2010 (online)

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Abstract

This paper describes a simple and efficient method with which to prepare C-8 modified 2-keto-3-deoxy-d-manno-octulosonic acid (KDO) derivatives from C-5 modified arabinose derivatives.

Key words

carbohydrates - ulosonic acids - aldol condensation - benzylation - protecting groups

21

General procedure for the synthesis of KDO and C-8 modified derivatives: d-Arabinose (500 mg, 3.3 mmol) was added to a solution of Na2CO3 (860 mg, 8.1 mmol) in H2O (8 mL). Oxalacetic acid (525 mg, 4.0 mmol) was added portionwise over 5 min, and the solution was adjusted to pH 11 using NaOH (10 M). After stirring for 2 h at r.t. the solution was acidified to pH 5 using AcOH, NiCl2 (7.5 mg, 0.03 mmol) added, and the mixture was heated at 50 ˚C for 1 h. After cooling to r.t., the reaction was neutralised to pH 8 with ammonia and the KDO product was isolated by column chromatography using CG-400 (HCO3 -) resin, washing first with H2O and then eluting with ammonium hydrogen carbonate (0.5 M). The eluant was concentrated under reduced pressure, and then freeze-dried. The lyophilised residue was purified using reversed-phase (C18) silica gel with H2O as the mobile phase. Fractions containing KDO can be visualised as bluish-grey spots on silica gel TLC plates (CHCl3-MeOH-H2O, 5:5:1) by staining with anisaldehyde-sulfuric acid dip.