Carba-sugars natural

There are two forms of carba-sugar carba-pyranoses and -furanoses. The former, especially the carba-hexopyranoses, have been extensively studied during the past two decades, ever since their derivatives were found in Nature as components of important antibiotics. However, very little is known about carba-furanoses, except for 4a-carba-)3-L-arabinofuranose ... 

Amino carba-sugars having an amino group other than at C-1 have never been discovered in Nature, but the eighteen compounds have been prepared in DL forms, and four enantiomers were synthesized during the course of the studies. 

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