We demonstrate a new strategy for designing reversibility, fatigue resistance and fluorescence switching materials, which are based on pyrazolone derivatives by introducing a pyridine ring. The reversible "on" and "off" modulation of fluorescence emission was up to 95% in the solid state.

A mild, efficient and catalytic ligand-free method for the direct arylation of 5-pyrazolones by Pd-catalyzed C-H bond activation is reported. The process smoothly proceeds and yields are moderate to excellent.

BACKGROUND Pyrazolones are traditionally synthesized by the reaction of β-keto esters with hydrazine and its derivatives. There are methods to synthesize β-keto esters from esters and aldehydes, but these methods have main limitation in varying the substituents. Often, there are a number of methods such as acylation of enolates in which a chelating effect has been employed to lock the enolate a...

To the allergologist, hypersensitivity to drugs means immunological drug reactions as classified in the Gell and Coombs system. To others, it may also include non-dose related adverse drug reactions including the non-immune mediated idiosyncratic drug reactions (type B). In the following discussion the broad definition of idiosyncrasy including all type B reactions and a clinical approach rathe...

BACKGROUND Allergic reactions to drugs constitute one of the most frequent reasons for consultations in Allergology services with an increasing prevalence in recent years. OBJECTIVES To describe the results of the Alergológica-2005 study on the clinical characteristics of patients consulting for suspected drug allergies. METHODS Alergológica-2005 was a descriptive, cross-sectional, prospect...

Receptors. In their Communication (e202216011), Jan J. Weigand et al. report the selective separation of lithium, magnesium, and calcium using 4-phosphoryl pyrazolones as pH-regulated receptors.

The enantioselective synthesis of pyrazol-3-ones has not been extensively studied in organic synthesis. Here in we report the first asymmetric addition of pyrazolones to maleimides catalyzed by bifunctional thiourea catalysts.

Background Immediate selective hypersensitivity reactions to pyrazolones are thought to be mediated by specific-IgE antibodies. The diagnosis of selective reactions to pyrazolones is mainly based on the clinical history, skin testing and/ or drug provocation test (DPT). Skin testing has low sensitivity and has potential risk of eliciting an anaphylactic response as well as DPT. Therefore the us...