Biocompatible Native Hyaluronan Nanofibers Fabricated via Aqueous PEO-Assisted Electrospinning and Heat-Quench Process.

Hyaluronan (HA) is widely used in cosmetic and biomedical applications due to its excellent biocompatibility and potential to promote wound healing. Nanofibrous HA, mimicking the extracellular matrix (ECM), is considered promising for therapeutic and cosmetic applications. However, the electrospinning process of HA often necessitates cytotoxic solvents and chemical modifications, compromising its biocompatibility and advantageous properties.

4-Hydroxymethyl-substituted oxazolidinone synthesis by tetraarylphosphonium salt-catalyzed reactions of glycidols with isocyanates.

Preparation of 4-hydroxymethyl-substituted oxazolidinones including optically active ones, in which tetraarylphosphonium salts catalyze the reaction of glycidol with isocyanates effectively, is described. The neutral catalysis facilitates glycidol addition to isocyanates followed by intramolecular cyclization. Mechanistic studies suggest that hydrogen-bonding interactions with the catalyst play an important role in the reaction progress.

Tetraarylphosphonium Salt-Catalyzed Synthesis of Oxazolidinones from Isocyanates and Epoxides.

Preparation of a range of oxazolidinones, including enantioenriched N-aryl-substituted oxazolidinones, in which tetraarylphosphonium salts (TAPS) catalyze the [3 + 2] coupling reaction of isocyanates and epoxides effectively, is described. The key finding is a Brønsted acid/halide ion bifunctional catalyst that can accelerate epoxide ring opening with high regioselectivity. Mechanistic studies disclosed that the ylide generated from TAPS, along with the formation of halohydrins, plays a crucial role in the reaction with isocyanates.