CHEMISTRY OF CARBA-SUGARS (PSEUDO-SUGARS) AND THEIR DERIVATIVES

This chapter focuses on the chemistry of carbahexopyranoses and their derivatives. The first three carbasugars were synthesized by McCasland and coworkers. Two other carbasugars were prepared from myo-inositol and the remaining eleven carbasugars have been synthesized from the Diels–Alder adduct of furan and acrylic acid. Fifteen enantiomers have been synthesized among the thirty-two carbasugars theoretically predicted. D-Fructose is the sweetest sugar known in naturally occurring carbohydrates and its intense sweetness is produced only by β-D-fructopyranose. Carbaglycosylamines [2,3,4-trihydroxy-5-(hydroxymethyl)-1-cyclohexylamine] and related compounds are well known to exist as the components of antibiotic validamycin complex and carbaoligosaccharidic alpha amylase inhibitor. Carbadisaccharides are carbocyclic analogs of true disaccharides in which one or both of the hexose or pentose residues is(are) replaced with a carbasugar. Besides sweetness, a carbasugar may have biological activity owing to its structurally close resemblance to a true sugar. The chemistry of carba-sugars is a newly opened area ofchemistry and the biological effects of these compounds have not been well studied, except for (1) the equisweetness of D-carba-glucose, D-carba-galactose, and D-carba- fructose with the respective true sugars, (2) the antibiotic activity of α-D- carba-galactose, and (3) the inhibition of a D-glucose-stimulated insulin release by D-carba-glucose. © 1990 Academic Press Inc.