Homocoupling of benzyl pyridyl ethers visible light-mediated deoxygenation.

The photocatalytic coupling of ethers is uncommon because of the challenges in breaking C-O bonds and low selectivity. Herein, we report a visible light-mediated deoxygenation homocoupling of benzyl pyridyl ethers their pyridium salts. This approach enables C(sp)-O bond homolysis under mild conditions.

Synthesis of Unnatural α-Amino Acids from (Pyridin-2-yl) Carbamate via CIPE-Induced Carbonyl Migration.

Synthetic methods of unnatural α-amino acids have always been the focus of extensive research due to their significant bioactivities. However, convenient transition-metal-free catalyzed methods are still in demand. Herein, we report a novel strategy for the construction of an unnatural α-amino acid skeleton via intramolecular rearrangement of carbamates, which are readily available from amines and their common protecting groups.

Visible Light-Induced Deoxygenation and Allylation/Vinylation of Pyridyl Ethers.

The generation of alkyl radicals by deoxygenation of unactivated ethers under visible light catalysis is a hitherto unmet challenge. Herein, we report a visible light-induced deoxygenation of pyridyl ethers via formation of their pyridinium salts. The generated benzylic radicals further react with allyl/alkenyl sulfones to provide a series of coupling products in good to moderate yields.

Synthesis of a New Amino-Furopyridine-Based Compound as a Novel Fluorescent pH Sensor in Aqueous Solution.

Development of new fluorescent molecules, especially pH-sensitive fluorescent dyes, is always in high demand due to their wide applications in various fields and the limited number of common chromophores. In this work, a family of 3-amino--phenylfuro[2,3-]pyridine-2-carboxamides () was synthesized as novel fluorescent compounds. Besides fluorescence in an organic solvent, and exhibit good fluorescence properties in both acidic and basic aqueous solution, which could be explained by protonation or different conformations formed in solution.

Determination of 3,5-Dinitrosalicylic Acid Hydrazide in Honey by Solid-Phase Extraction-Ultraperformance Liquid Chromatography-Tandem Mass Spectrometry.

Abstract: 3,5-Dinitrosalicylic acid hydrazide (DNSAH) is the metabolite of the antibacterial nitrofuran nifursol. A simple and accurate analytical method to determine DNSAH levels in honey by solid-phase extraction-ultraperformance liquid chromatography-tandem mass spectrometry has been established. The honey sample was hydrolyzed under acidic conditions and derivatized with 2-nitrobenzaldehyde in the dark for 16 h, followed by solid-phase extraction and column chromatography.