Pd-Catalyzed Coupling of Bromo-N- (ß-glucopyranosyl)quinolin-2-ones with Amides: Synthesis of N-glucosyl-6BrCaQ Conjugates with Potent Anticancer Activity.

A series of N-glycosyl- 6BrCaQ conjugates was synthesized through a Pd-catalyzed cross-coupling reaction between brominated N-glycosyl quinolin-2-one derivatives and various nitrogen nucleophiles. Antiproliferative assays revealed that this new series of analogues represents a promising class of antitumor compounds as illustrated by the high biological activity observed for several derivatives towards different cancer cell lines compared to the non-glycosylated congeners.

A new chiral rare-earth organic framework constructed by tartaric acid: synthesis, structural, thermal investigations and optical properties.

Hydrothermal reactions of rare-earth cerium with L-tartaric acid afford a new coordination polymer, namely, poly[[triaqua(µ4-L-tartrato)cerium(III)] chloride], {[Ce(C4H4O6)(H2O)3]Cl}n, (1). The structure was determined by single-crystal X-ray diffraction analysis and further characterized by IR and UV-Vis spectroscopy, powder X-ray diffraction and thermogravimetric analysis. Single-crystal X-ray diffraction analysis revealed that the compound is a new two-dimensional (2D) double-layered structure with one-dimensional left-handed helical chains. The different intermolecular interactions were confirmed using Hirshfeld surface analysis and molecular fingerprint plots. Molecular 2D fingerprint plots quantify the different interactions and highlight that H...H (24.8%), H...O/O...H (26.3%), Cl...H/H...Cl (19.6%), O...O (13.8%) and Ce...O/O...Ce (13.6%) interactions account for 99.8% of all contacts. Additionally, the photoluminescence properties of the compound were investigated in the solid state.

Highly Luminescent Europium-Based Heteroleptic Coordination Polymers with Phenantroline and Glutarate Ligands.

Isostructural lanthanide-based coordination polymers with general chemical formula [Ln(phen)(glu)(NO3)]∞ with Ln = La-Tm (except Ce and Pm) have been synthesized by hydrothermal methods (H2glu stands for glutaric acid and phen stands for 1,10-phenantroline). They crystallize in the monoclinic system with the P21/c (no. 14) space group. The crystal structure has been solved on the basis of the La derivative. It can be described as the superimposition of molecular chains of dimeric La(phen)(NO3)-La(phen)(NO3) units bridged by glutarate ligands. Luminescent properties have been explored and show that the Eu derivative exhibits the highest luminance observed for Eu-based coordination polymers (85 to 105 cd·m-2). Effects of the dilution of the Eu3+ and Tb3+ luminescent ions by Gd3+ optically inactive ions are unexpected and to the best of our knowledge unprecedented. This could be related to the different intermetallic energy-transfer mechanisms in competition and to the nonisotropic distribution of the lanthanide ions in these molecular alloys. The investigation of molecular alloys with general chemical formula [Eu1-xTbx(phen)(glu)(NO3)]∞ with 0 ≤ x ≤ 1 highlights a very sizable and constant Eu3+ luminescence whatever the x value, which further confirms the existence of very strong intermetallic energy transfers in this family of compounds. It is also noticeable that some coordination polymers based on weakly emissive lanthanide ions exhibit very well defined emission spectra.

Synthesis of N-Glycosyl-2-oxindoles by Pd-Catalyzed N-Arylation of 1-Amidosugars.

An efficient intramolecular Pd-catalyzed N-arylation of o-iodo-amidosugars for the synthesis of N-glycosylated oxindoles has been reported. The coupling reaction takes place in toluene and involves Pd(OAc)2/RuPhos catalytic systems in the presence of K2CO3. This versatile approach was extended successfully to the synthesis of other N-glycosylated heterocycles.

Copper-Catalyzed Anomeric O-Arylation of Carbohydrate Derivatives at Room Temperature.

Direct and practical anomeric O-arylation of sugar lactols with substituted arylboronic acids has been established. Using copper catalysis at room temperature under an air atmosphere, the protocol proved to be general, and a variety of aryl O-glycosides have been prepared in good to excellent yields. Furthermore, this approach was extended successfully to unprotected carbohydrates, including α-mannose, and it was demonstrated here how the interaction between carbohydrates and boronic acids can be combined with copper catalysis to achieve selective anomeric O-arylation.

One-Pot Assembly of Unsymmetrical Biaryl Thioglycosides through Chemoselective Palladium-Catalyzed Three-Component Tandem Reaction.

A range of unsymmetrical biaryls bearing thiosugars could be synthesized in a one-pot multicomponent approach using one catalytic palladium system that permitted the C-S and C-C bonds to be formed sequentially. The reaction showed a high selectivity and was applied to a broad variety of substrates giving access to novel glycosylated biaryl structures in good yields.

Convergent Synthesis of N,S-bis Glycosylquinolin-2-ones via a Pd-G3-XantPhos Precatalyst Catalysis.

Buchwald-Hartwig-Migita cross-coupling of 1-thiosugars with α- or ß-3-iodo-N-glycosylquinolin-2-ones has been accomplished under mild and operationally simple reaction conditions through the use of a Pd-G3 XantPhos palladacycle precatalyst. This new methodology has been successfully applied to a variety of α- or ß-mono-, di-, and poly-thiosugar derivatives to efficiently synthesize a series of α- or ß-N,S-bis-glycosyl quinolin-2-ones, which are difficult to synthesize by classical methods.

Stereoretentive Copper-Catalyzed Directed Thioglycosylation of C(sp2 )-H Bonds of Benzamides.

An efficient thioglycosylation of C(sp2 )-H bonds with thiosugars has been established for the first time. Using only Cu(OAc)2 ⋅H2 O as a catalyst and Ag2 CO3 as an additive in DMSO, the protocol proved to have broad scope, and a variety of complex thioglycosides have been prepared in good yields with exclusive ß-selectivity.

Sulfur-capped cyclodextrins: a new class of cavitands with extroverted as well as introverted donor functionalities.

Ansa-cyclodextrins were obtained in high yields by reaction of sodium sulfide with A,B-di- or A,B,D,E-tetramesylated alpha-CD precursors; the resulting thiocavitands are suitable for forming nanotubular molecules, as well as for hosting metal-organic fragments.

A new approach to A,B-difunctionalisation of cyclodextrins using bulky 1,3-bis[bis(aryl)chloromethyl]benzenes as capping reagents.

1,3-Bis[bis(4-tert-butylphenyl)chloromethyl]benzene and 1,3-bis[bis(4-anisyl)chloromethyl]benzene were employed as regioselective capping reagents for the preparation of C-6A,C-6B-bridged, permethylated alpha- and beta-CD derivatives; isolated yields up to 55% of proximally capped, methylated CDs were obtained, thus opening the way to the straightforward preparation of a wide range of A,B-functionalised CDs. As revealed by a single crystal X-ray diffraction study, the benzene-1,3-bis[bis(4-tert-butylphenyl)methyl] spacer is perfectly suited for A,B-capping of beta-cyclodextrin.

A polynuclear coordination glutarate of lanthanum(III) with an uncommon cage feature.

The title compound, triaquatris(glutarato)dilanthanum(III) dihydrate, [[La2(C5H6O4)3(H2O)3] x 2H2O]n, is the first reported glutarate coordination polymer of lanthanum(III) without a protonated ligand. The noteworthy features in the structure are, firstly, the unusual binuclear lanthanum cage formed by three bridging bonds through O atoms involved in different coordination modes and, secondly, the very rare 'malonate' mode exhibited by a dicarboxylate ligand with an alkyl chain of five C atoms. To our knowledge, this eta7 chelation for the glutarate ligand has not been reported and was thought to be forbidden for steric reasons. The gauche-gauche conformation of the corresponding ligand favours cage formation, but trans geometries created along the ligating O atoms prevent cluster packing. The two independent La atoms are nine- and tenfold coordinated, leading to distorted one-face-sharing LaO7(H2O)2 and LaO9(H2O) polyhedra, respectively. In the three-dimensional framework, these asymmetric subunits are linked in a zigzag manner via one-edge-sharing LaO9(H2O) polyhedra and are connected by the carbon backbone chains of the ligands. The structure is very compact and, unlike many other reported dicarboxylate lanthanides, connectivity between the two metal atoms and the three ligands yields a crystal packing with cavities accommodating two guest water molecules but without an open framework.