Synthesis and Biological Evaluation of 6-[(1 R)-1-Hydroxyethyl]-2,4a( R),6( S),8a( R)-tetrahydropyrano-[3,2- b]-pyran-2-one and Structural Analogues of the Putative Structure of Diplopyrone.

The phytotoxin diplopyrone is considered to be the main phytotoxin in a fungus that is responsible for cork oak decline. A carbohydrate-based synthesis of the enantiomer of the structure proposed for diplopyrone has been developed from a commercially available derivative of d-galactose. Key steps in the synthesis are a highly stereoselective pyranose chain-extension based on methyltitanium, preparation of a vinyl glycoside via Isobe C-alkynylation-rearrangement/reduction, and RCM-based pyranopyran construction.

Synthesis of lemonose derivatives: methyl 4-amino-3-O,4-N-carbonyl-2,4,6-trideoxy-3-C-methyl-α-l-lyxo-pyranoside and its phenyl thioglycoside.

Lemonose is a component of the antibiotic lemonomycin and other antibiotics and natural products. Three routes to the synthesis of the title compound, a protected, desmethyl derivative of lemonose, from l-rhamnose or its glycal, were investigated based on electrophilic cyclization, epoxidation-ring opening, and deoxygenation of an intermediate that was used in the synthesis of the amino sugar callipeltose. The deoxygenation route was successful and it provided the title compound, which was then converted to a phenyl thioglycoside.

Structural, electronic and acid/base properties of [Ru(bpy(OH)2)3]2+ (bpy(OH)2 = 4,4'-dihydroxy-2,2'-bipyridine).

We have synthesized the complex [Ru(bpy(OH)(2))(3)](2+) (bpy(OH)(2) = 4,4'-dihydroxy-2,2'-bipyridine) containing ligands that can be readily deprotonated. Both experimental and computational techniques were utilized to perform a thorough analysis of the structural and electronic properties of the complex in both the protonated and deprotonated state. The complex [Ru(bpy(OMe)(2))(3)](2+) (bpy(OMe)(2) = 4,4'-dimethoxy-2,2'-bipyridine) was also synthesized and studied, because the bpy(OMe)(2) ligand has electron-donating properties like bpy(OH)(2), but does not contain deprotonatable groups.