5- Thio-D-fructofuranose

Thio-D-fructofuranose (88) was prepared from 5-(9-tosyl-l,3-(9-isopropylidcnc-o -L-sorbopyranose (87) by the standard sequence of reactions shown in Scheme 26. The H and C NMR spectra of 88 in aqueous solution show only tlie signals of the furanose a and p anomers in the ratio of 11 89, whereas tlie NMR spectra of D-fructose in D2O show the presence of the -pyranose, -furanose, a-furanose, and a-pyranose in the ratio of 6 3 1 trace, respectively. Partial hydrolysis or methanolysis of 90, prepared from 1,6-di-O-tosyl-D-fructofuranose (89), gave 3,6-anhydro-l-deoxy-6-thio-D-oraZ)W7o (or D-yv/o)-hexulose (91). Nucleophilic attack of the ring sulfur atom on C-3... 

Penta-0-acetyl-5-thio-p-i>fructofuranose, T-6I l-0,2-0,3-0,4-0,5-S-Pentaacetyl-5-thio-p-D-fructopyranose, T-61 l-0,3-0,4-0,5-5,6-0-Pentaacetyl-5-thio-D-fructose, T-61 l-0,2-0,3-0,5-5,6-0-Pentaacetyl-5-thio-p-D-gaIactofuranose, T-66... 

Deoxy-6-iodo-a-D-fructofuranose p-D-fructopyranose 1,2 2,1 -dianhydride (49) 6-Chloro-6-deoxy-a-D-fructofuranose p-D-fructopyranose 1,2 2,1 -dianhydride (50) 6-5-Heptyl-6-thio-tt-D-fructofuranose p-D-fructopyranose 1,2 2,l -dianhydride (51) 6-Azido-6-deoxy-a-D-ffuctofuranose P-D-fructopyranose 1,2 2,l -dianhydride (52) 6-Anuno-6-deoxy-a-D-fructofuranose p-D-fructopyranose 1,2 2,l -dianhydride (53) 6-Acetamido-6-deoxy-a-D-fructofuranose p-D-fructopyranose 1,2 2,l -dianhydride (54)... 

As has already been discussed, eclipsed, and anti, vicinal hydroxyl groups are not expected to elicit the sweet taste. Thus, Shallenberger suggested that jS-D-fructofuranose would be expected to have very little sweetness. The taste of this sugar has yet to be confirmed, but, significantly, Lindley and coworkers found that 5-thio-)8-D-fructofuranose is practically devoid of sweet taste. However, methyl )3-D-glucofuranoside (40) and some of the... 

---