C-glyco"RGD" as αIIbß3 and αvß integrin ligands for imaging applications: Synthesis, in vitro evaluation and molecular modeling.

The design of conjugates displaying simultaneously high selectivity and high affinity for different subtypes of integrins is a current challenge. The arginine-glycine-aspartic acid amino acid sequence (RGD) is one of the most efficient short peptides targeting these receptors. We report herein the development of linear and cyclic fluoro-C-glycoside"RGD" conjugates, taking advantage of the robustness and hydrophilicity of C-glycosides. As attested by in vitro evaluation, the design of these C-glyco"RGD" with a flexible three-carbon triazolyl linker allows distinct profiles towards αIIbß3 and αvß3 integrins. Molecular-dynamics simulations confirm the suitability of cyclic C-glyco-c(RGDfC) to target αvß3 integrin. These C-glyco"RGD" could become promising biological tools in particular for Positron Emission Tomography imaging.

Value-added carbohydrate building blocks by regioselective O-alkylation of C-glucosyl compounds.

Functionalized carbohydrates and especially functionalized C-glycosides are useful intermediates for the synthesis of complex carbohydrates of interest. In this paper, we describe the synthesis of C-azidopropylglucopyranosides and give a full account of their regioselective acylation and alkylation. Alkylation of these C-glucosyl compounds containing 1,2-trans-diol, namely 2- and 3-OH were first optimized with benzyl bromide. The reaction has then been extended to various electrophiles thus providing 3-O-substituted C-glucosyl compounds. These results are one of the first examples of regioselective alkylation with functionalized electrophiles on glycosyl compounds featuring a trans-vicinal diol. Furthermore, we describe some results obtained during regioselective deprotection of 4,6-O-benzylidene protecting group. This work opens the way to the synthesis of complex carbohydrate derivatives.

Synthesis and revised stereochemical assignment of C-allyl glucopyranosides and derivatives.

α- and ß-C-allylglucopyranosides and hydroxy-, bromo- and azido-derivatives were prepared through allylation at C-1 of methyl 2,3,4,6-tetra-O-benzyl-D-glucopyranoside or 1-O-acetyl-2,3,4,6-tetra-O-benzyl-D-glucopyranose and subsequent chemical modifications of the alkene on the anomeric arm. However, we picked out some discordance between some recent published studies and our results. After a thorough work of characterization and NMR analysis, we unambiguously confirmed α and ß stereochemistry of the two series of compounds and fully described for the first time ß-C-propyl alcohol, bromide and azide of 2,3,4,6-tetra-O-benzyl-D-glucopyranose.