Thio-sugars and other Sulphur-containing Compounds

Thio-sugars and Other Sulphur-containing Compounds 

Reagents i, CHj=CHCHjBr-AgjO ii, MeONa-MeOH iii, PhCH Cl-KOH iv, HCl-H O-p-dioxan  

Treatment of 2,3,4,6-tetra-0-acetyl-)S-D-glucopyranosyl dimethyldithiocarbam-ate (252) with phenylmercury(ii) acetate gave the acetylated 1-S-phenylmercury-(ii)thio-)S-D-gIucopyranose (253), which could also be prepared in high yield from other dithiocarbamates and from 2,3,4,6-tetra-0-acetyl-l-thio-/ -D-glucopyranose and its S-acetyl derivative. Demercuration of (253) with hydrogen sulphide provided a convenient synthesis of 2,3,4,6-tetra-0-acetyl-l-thio-/5-D-glucopyranose, 

The formation of 1-thioglycosides when 2-thioxo-l,3,4-thiadiazoles react with 2,3,4,6-tetra-O-acetyl-a-D-gIucopyranosyl bromide is noted in Chapter 9. Other references to 1-thioglycosides will be found in Chapters 6 and 16. 

6-dixanthates (258) and (259) have been prepared from ethyl 2,3-dideoxy-OL-D-erythro- and -t/irco-hex-2-enopyranoside, respectively, and on thermolysis they underwent suprafacial [3,3]sigmatropic rearrangements to give the corresponding 3,4-unsaturated 2-(methylthio)carbonylthio compounds.  

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Thio-sugars and Other Sulphur-containing Compounds 95... 

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