Monosulfate structure

In 1921 Helferich [34J found that treatment of methyl a-D-glucopyranoside 18 with sulfuryl chloride in a mixture of pyridine and chloroform at 5°C afforded a compound, the structure of which was established several years later [37,38] to be that of methyl 4,6-dichloro-4,6-dideoxy-a-D-galactopyranoside 2,3-cyclic sulfate (19 Scheme 3). The cyclic sulfates are readily cleaved by dilute alkalis, or by methanolic ammonia, to give the salt of a monosulfate the hemi-ester is then desulfated by acid to yield the chlorodeoxy sugar [35,36]. Both of these reactions occur with retention of configuration [37]. 

While early workers suggested the 03 sulfate structure for 18 based on chemical reactivity (1), x-ray analysis (26) and NMR data (6) have shown the stable monosulfate to be the 02 structure. 

The absolute configuration of kanamycin A was determined by chemical studies, and by X-ray analysis of its monosulfate monohydrate.From the results obtained by X-ray analysis, the structures of the kanamycins (1, 2, and 3), neamine (4), and paromamine (5) (together with the numbering of the carbon atoms) are shown. 

This substance is a mixture of many individual substances and cannot be adequately represented by a single molecular structure Synonyms kanamycin monosulfate 0-3-amino-3-deoxy-a-D-glucopyranosyl-(i-6)-0-[6-amino-6-deoxy-a-D-glucopyranosyl-(i-4)]-2-deo3 -D-streptamine sulfate (1 1) (salt)... 

In an excellent study, White and Catterick [1033] characterized and analyzed 40 acidic dyes according to their composition, shape, and retention on a PLRP-S column (photodiode array detector, A = 190-600 nm). A 50/50 acetonitrile/water (0.7 g/L citric acid with 3.4 g/L tetrabutylammonium hydrogen sulfate adjusted to pH 9.0 with ammonia) mobile phase was used. Five classes of dyes were included in the study phenyl-N=N-monosulfonated naphthols, naphthyl-N=N-naphthols, phenyl-N=N-p-hydroxyIated nt hthyls, monosulfated phenyl-N=N-naphthols, and phenyl-N=N-disulfonated naphthols. Tables were generated in which the relative retention times, relative ahsoihances (vs. 500nm) for 250-450 nm (50 nm intervals), and UV maximum absorbances were listed. Fran positional/spatial arguments and data presented in the study, information about the chemical structure of an analyte could be determined with as little as 100 ng of sample. Structures were presented for all compounds. 

Since ettringite forms a diffusion barrier around the C3A grains, the hydration reaction is initially delayed. Only after about 12 h will this barrier be broken by the onset of transformation of ettringite into monosulfate (Figure 5.7). This reaction is reversible, as the monosulfate can retransform to ettringite in the presence of sulfate ions in the groundwater, leading to the stmctural destruction of concrete, as can be observed on many urban concrete structures. In modern sulfate-resistant... 

---