Preparation of amidine derivatives from 1-cyano-d-galactal

Pd-catalyzed coupling reactions of anhydro-aldose tosylhydrazones with aryl bromides to produce substituted exo-glycals

Palladium-catalyzed cross-couplings of O-peracylated and O-permethylated 2,6-anhydro-aldose tosylhydrazones with aryl halides were studied under thermic conditions in the presence of LiOtBu and phosphine ligands. The reactions gave the corresponding aryl substituted exo-glycals as mixtures of diastereomers in 11-75% yields. The transformations represent a new access to these types of glycomimetic compounds. The double bond of some aryl substituted exo-glycals was saturated to give good yields of benzylic C-glycosyl derivatives.

The first general synthesis of 2-C-(β-d-glycopyranosyl)pyrimidines and their evaluation as inhibitors of some glycoenzymes

The first systematic study on the synthesis of 2-C-(β-d-glycopyranosyl)pyrimidines either from amidine A or glycosyl cyanides B and 1,3-dicarbonyl compounds.

Improved preparation of 4(5)-aryl-2-(β-d-glucopyranosyl)-imidazoles, the most efficient glucose analogue inhibitors of glycogen phosphorylase

Large scale (up to 20 g) preparation ofIandIIallowed the best inhibitors of glycogen phosphorylaseIIIto be synthesized in close to 60% overall yields fromI.

Preparation of 1-C-glycosyl aldehydes by reductive hydrolysis

Reductive hydrolysis of various protected glycosyl cyanides was carried out using DIBAL-H to form aldimine alane intermediates which were then hydrolyzed under mildly acidic condition to provide the corresponding aldehyde derivatives. While 1-C-formyl glycal and 2-deoxy glycosyl derivatives were stable during isolation and storage 1-C-glycosyl formaldehydes in the gluco, galacto and manno series were sensitive and decomposition occurred by 2-alkyloxy elimination. A one-pot method using N,N'-diphenylethylenediamine to trap these aldehydes in stable form was developed. Reductive hydrolysis of glycosyl cyanides offers valuable aldehyde building blocks in a convenient way which can be applied in the synthesis of complex C-glycosides.