Different anchoring groups have been studied with the aim of covalently binding organic linkers to the surface of alumina ceramic foams. The results suggested that a higher degree of functionalization was achieved with a pyrogallol derivative − as compared to its catechol analogue − based on the XPS analysis of the ceramic surface. The conjugation of organic ligands to the surface of these alumina materials was corroborated by DNP-MAS NMR measurements.

A simple protocol for the synthesis of 3-amino-[1,2,4]triazolo[4,3-a]pyridines is reported. The newly developed one-pot methodology involves the reaction of hydrazinopyridine with isothiocyanates to give the corresponding thiosemicarbazides, which are further desulfurized in situ using polymer-supported Mukaiyama's reagent to promote the final cyclization and formation of the central core. Aryl isothiocyanates bearing both electron-donating and electron-withdrawing groups are well tolerated, and the expected compounds were obtained in excellent purities and yields after removal of salts with a SPE-NH2 column. This methodology proved to be robust in the extension to 3-amino-[1,2,4]triazolo[4,3-a]-pyrazines and 3-amino-[1,2,4]triazolo[4,3-c]-pyrimidines, and no significant differences were noticed in terms of purities and yields. The straightforward protocol developed, mix, filter, and evaporate, is appropriate for performing multiple reactions in parallel fashion without need of purification.

To control the selective adhesion of human endothelial cells and human serum proteins to bioceramics of different compositions, a multifunctional ligand containing a cyclic arginine-glycine-aspartate (RGD) peptide, a tetraethylene glycol spacer, and a gallate moiety was designed, synthesized, and characterized. The binding of this ligand to alumina-based, hydroxyapatite-based, and calcium phosphate-based bioceramics was demonstrated. The conjugation of this ligand to the bioceramics induced a decrease in the nonselective and integrin-selective binding of human serum proteins, whereas the binding and adhesion of human endothelial cells was enhanced, dependent on the particular bioceramics.

Bone substitute materials permissive for trans-scaffold migration and in-scaffold survival of human bone-derived cells are mandatory to develop cell-engineered permanent implants to repair bone defects. In this study, we evaluated the influence on human bone-derived cells of the material composition and microstructure of foam scaffolds made from calcium aluminate using a direct foaming method allowing wide-range tailoring of the microstructure for pore size and pore openings. Human fetal osteoblasts attached to the scaffolds, migrated across the entire materials depending on the scaffold pore size, colonized and survived in the porous material for at least 6 weeks. The long-term biocompatibility of the scaffold material for human cells was evidenced by in scaffold determination of cell metabolic activity using a modified MTT assay, a repeated WST-1 assay and scanning electron microscopy. Finally, we demonstrated that the fetal cells can be covalently bound to the scaffolds using biocompatible click chemistry, thus enhancing the rapid adhesion of the cells to the scaffolds. Thus, the different microstructures of the foams influenced the migratory potential of the cells, but not cell viability, and the scaffolds were permissive for covalent biocompatible chemical binding of the cells to the materials, allowing either localized or widespread cellularization of the scaffolds for cell-engineered implants.

The first total synthesis of (±)-prelunularin is described employing an intramolecular aldol addition/sulfinate elimination tandem reaction. Investigations on the mechanism of the one-pot cyclization reaction using time-dependent NMR spectroscopy suggested that the sulfinate elimination took place before the intramolecular ring-closing aldol addition.

Compounds belonging to the 5-acyl-3,4-dihydropyrimidine-2-thione family were obtained using a solvent-free Biginelli condensation with or without the use of a catalyst. An unprecedented solid-phase procedure involving a polymer-supported aldehyde allowed the preparation of a series of 5-aroyl derivatives starting with crude diketones obtained from their corresponding aryl esters.

No abstract

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.