title: Synthesis of the branched-chain sugar aceric acid: a unique component of the pectic polysaccharide rhamnogalacturonan-II.
abstract: Described herein is the synthesis of 3-C-carboxy-5-deoxy-L-xylose (aceric acid), a rare branched-chain sugar found in the complex pectic polysaccharide rhamnogalacturonan-II. The key synthetic step in the construction of aceric acid was the stereoselective addition of 2-trimethylsilyl thiazole to 5-deoxy-1,2-O-isopropylidene-alpha-L-erythro-pentofuran-3-ulose (2), which was prepared from L-xylose. The thiazole group was efficiently converted into the required carboxyl group via conventional transformations. Aceric acid was also synthesized by dihydroxylation of a 3-C-methylene derivative of 2 followed by oxidation of the resulting hydroxylmethyl group. The C-2 epimer of aceric acid was also synthesized using thiazole addition chemistry, starting from L-arabinose.
authors.affiliation: School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich NR4 7TJ, UK.
authors.forename: Nigel A
authors.initials: NA
authors.lastname: Jones
authors.forename: Sergey A
authors.initials: SA
authors.lastname: Nepogodiev
authors.forename: Colin J
authors.initials: CJ
authors.lastname: MacDonald
authors.forename: David L
authors.initials: DL
authors.lastname: Hughes
authors.forename: Robert A
authors.initials: RA
authors.lastname: Field
mesh_terms: D002241:Carbohydrates / Q000138:chemical synthesis*; D015394:Molecular Structure; D010368:Pectins / Q000737:chemistry*; D013400:Sugar Acids / Q000138:chemical synthesis* / Q000737:chemistry*; D014994:Xylose / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry
chemical_list: C511260:3-C-carboxy-5-deoxyxylose; D002241:Carbohydrates; D013400:Sugar Acids; C042492:rhamnogalacturonan II; D010368:Pectins; D014994:Xylose