Fructopyranose

P-D-fructofuranose a-D-glucopyranose 1,2 2,1 -dianhydride a-D-fructofuranose a-D-glucopyranose 1,1 2,2 -dianhydride P-D-fructofuranose a-D-glucopyranose 1,1 2,2 -dianhydride P-D-fructopyranose a-D-glucopyranose 1,1 2.2 -dianhydride P-D-fructofuranose a-D-glucopyranose 2,1 3,2 -dianhydride P-D-fructopyranose a-D-sorbopyranose 1,2 2,1 -dianhydride P-D-fructopyranose a-L-sorbopyranose 1,2 2,1 -dianhydride di-a-L-sorbofuranose 1,2 2,3 -dianhydride a-l-sorbofuranose a-L-sorbopyranose 2,1 3,2 -dianhydride di-a-L-sorbopyranose 1,2 2,1 -dianhydride a-D-sorbopyranose a-L-sorbopyranose 1,2 2,1 -dianhydride di p-L-sorbopyranose 1,2 2,1 -dianhydride a-L-sorbopyranose p-L-sorbopyranose 1,2 2,1 -dianhydride a-L-sorbofuranose a-L-sorbopyranose l,2 2,l -dianhydride P-L-sorbofuranose a-L-sorbopyranose 1,2 2,1 -dianhydride a-L-sorbofuranose P-L-sorbofuranose l,2 2,l -dianhydride... 

O-a-D-Glucopyranosyl-a-D-fructopyranose 4-O-a-D-glucopyranosyl-P-D-fructopyranose 1,2 2,1 -dianhydride (23) 4-O-a-D-Galactopyranosyl-a-D-fructopyranose 4-O-a-D-galactopyranosyl-p-D-fructopyranose 1,2 2,1 -dianhydride (24)... 

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)... 

D-Fructose is the sweetest sugar known in naturally occurring carbohydrates, and its intense sweetness is produced only by ) -D-fructopyranose. "... 

The 6a-carba-y -D-fructopyranose molecule may have this tripartite arrangement (AH, B, and X) in almost the same emplacement as has the y -D-fructopyranose molecule. 

As it has been revealed that replacement of the ring-oxygen atom in a pyranoid sugar by a CH2 group is not detrimental to its sweetness, 6a-carba- -D-fructopyranose may have the same intense sweetness as D-fruc-tose. To substantiate this prediction, the following two reaction routes have been successfully developed for 6a-carba-y -DL-fructopyranose, as well as for the enantiomers. 

Treatment of inulin or D-fructose with liquid HF (neat or diluted with liquid SOj) gave a mixture of six di-D-fructose dianhydrides, including 23, 25, 27, and )3-D-fructofuranosyl ) -D-fructopyranose 2,l 3,2 -dianhydride... 

Support for this result was obtained from the taste of 1,5-anhydrohexitols, which, only for purposes of comparison, can be regarded as 1-deoxyal-dopyranoses. 1,5-Anhydro-D-glucitol (that is, the incorrectly named 1-deoxy-D-glucopyranose ) (14), 1,5-anhydro-D-mannitol ( 1-deoxy-D-mannopyranose or 2-deoxy-D-fructopyranose ) (15), and 1,5-anhydro-D-galactitol ( l-deoxy-o-galactopyranose ) (16) are all purely sweet, without any trace of bitterness. Furthermore, the complete absence of bitterness of 1,5-anhydromannitol (16) clearly indicates that the anomeric... 

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