ABSTRACT
The revision of the structures and properties of Calystegines shows that they can be regarded as carbohydrate mimics, with related biological activities and peculiar characteristics. Not only they can be isolated from food plants, but they can be obtained from a variety of monosaccharide derivatives and of non-carbohydrate products. Although several synthetic calystegine analogs have been reported as glycosidase inhibitors, new, more potent and effective inhibitors are required.
Subject(s)
Biomimetic Materials/chemistry , Carbohydrates/chemistry , Glycoside Hydrolases/antagonists & inhibitors , Plant Extracts/chemistry , Plants/chemistry , Tropanes/chemistry , Animals , Biomimetic Materials/chemical synthesis , Biomimetic Materials/pharmacology , Carbohydrates/chemical synthesis , Carbohydrates/pharmacology , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Glycoside Hydrolases/metabolism , Humans , Plant Extracts/chemical synthesis , Plant Extracts/pharmacology , Tropanes/chemical synthesis , Tropanes/pharmacologyABSTRACT
Reaction of 3-O-benzyl-1,2-O-isopropyl-idene-α-xylo-pentodialdo-1,4-furan-ose with N,N-diethyl-2-(dimethyl-sulfuranil-idene)acetamide gave stereoselectively an ep-oxy-amide, which was regioselectively opened by NaN(3) in dimethyl formamide to give the title compound, C(21)H(30)N(4)O(6). X-ray crystallography confirmed the relative stereochemistry of the title compound and the absolute configuration was determined by the use of d-glucose as the starting material. There are two mol-ecules in the asymmetric unit (Z' = 2). The crystal structure consists of two types of chains of O-Hâ¯O hydrogen-bonded mol-ecules running parallel to the b axis, with each mol-ecule acting as a donor and acceptor of one hydrogen bond.
ABSTRACT
We reacted N,N-diethyl-2-(dimethylsulfuranylidene)acetamide with 4,6-O-alkylidene-glycopyranoses under several experimental conditions and obtained, stereoselectively, derivatives of acyclic 3-(polyhydroxyalkyl)-alpha,beta-epoxyamides. In this way, and in one stage, we introduced, highly stereoselectively, two new chiral carbons with a substituted asymmetric epoxide group that could then be regioselectively transformed and, in addition, obtained highly functionalized acyclic structures starting from easily obtained cyclohemiacetalic monosaccharides. The configuration of the new chiral carbons of the resulting trans-epoxyamides was determined by comparing the IR, NMR, and polarimetric data with another epoxyamide of known configuration. We attempted to explain the stereochemistry of the major products by proposing a preferential conformation for the different starting aldehyde sugars in the basic reaction medium that took into account, at first, the principal electrical interactions between the carbonyl group and those unprotected hydroxyl groups with partial hydroxylate character and, secondarily, the preferred equatorial approach (exo) of the nucleophile. Finally, we studied the cyclization of the reaction products by an initial Payne transposition of the gamma-hydroxy-alpha,beta-epoxide to alpha-hydroxy-beta,gamma-epoxide, followed by its cyclization to a C-glycofuranoside.