This typhoid fever outbreak was detected because of an elevated number of IPs. Underreporting of milder illnesses and delayed and inadequate antimicrobial treatment contributed to the high perforation rate. Enhancing laboratory capacity for detection is critical to improving typhoid fever control.

A series of R-D-arabinofuranosyl oligosaccharides (2-8) that are fragments of the arabinan portions of two polysaccharides present in the cell wall of Mycobacterium tuberculosis have been synthesized. Preparation of the oligosaccharides involved the sequential addition of arabinofuranosyl residues from thioglycoside donors to methyl glycoside acceptors. High-resolution NMR studies on the final products provided all 3 J H,H values, which were in turn used in PSEUROT 6.2 calculations to determine both the identity and equilibrium populations of preferred conformers for each furanose ring in these glycans. Comparison of the ring conformers present in 2-8 with those available in the parent monosaccharide, methyl R-D-arabinofuranose (16), allowed the determination of the effect of glycosylation upon ring conformation. At equilibrium, 16 exists as an approximately equimolar mixture of O T 4 (North, N) and 2 T 3 (South, S) conformers. These studies showed that glycosylation of 16 at OH 5 resulted in no significant change in conformer identity or population relative to 16. However, glycosylation of OH 3 resulted in a change in the identity of the N species (to O E) and a significant favoring of this conformer at equilibrium. These trends were seen in all of the oligosaccharides. The populations of the three possible staggered rotamers (gg, gt, tg) about the C4-C5 bond were essentially the same for all residues in 2-8, and thus this equilibrium does not appear to be sensitive to glycosylation.

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Acetylated pyranose glycals have been converted through a convenient three-step process into protected furanose reducing sugars. Ozonolysis of 2,3,5-tri-O-acetyl-glucal or 2,3,5-tri-O-acetyl-galactal, followed by treatment with dimethyl sulfide and then hydrolysis gave respectively protected arabinofuranose (6) and lyxofuranose (7) derivatives. Conversion of these hemiacetals to oligosaccharides was explored using a number of methods. Activation of 6 or 7 in situ afforded glycosides in modest yield and stereoselectivity. Glycosylation of tetraacetates 16 and 18, obtained from 6 and 7, gave similar results. However, thioglycosides 17 and 19, also derived from 6 and 7, were found to be effective glycosyl donors, producing products in good to excellent yields and with high stereoselectivities. The method was also used to synthesize a disaccharide in which one residue contained uniform 13C enrichment.

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