Synthesis of nitrophenyl and fluorophenyl azides and diazides by SNAr under phase-transfer or microwave irradiation: Fast and mild methodologies to prepare photoaffinity labeling, crosslinking, and click chemistry reagents

Two fast and mild methodologies to prepare nitrophenyl and fluorophenyl azides are presented. These aryl azides are extensively used as crosslinking, photoaffinity labeling, and click chemistry reagents. Substituted aryl azides are prepared by performing a SNAr substitution on halogenated benzenes with a phase-transfer catalyst (PTC) such as tetraethylammonium tetrafluoroborate (TEATFB), the reaction proceeds in several hours under rather mild temperatures (25°C to 70°C). Furthermore, aryl azides are also prepared within minutes under microwave irradiation at slightly higher temperatures (50°C to 70°C). These procedures could be applied in the preparation of other aryl azides. In the case of substituted pentafluoro benzene (pF), the type of products obtained in each reaction depends on the amount of sodium azide and the strength and position of electron-withdrawing substituents (COH, COR, COOR, CN, NO2, or F). A discussion on the mechanisms and the products obtained in these SNAr reactions is presented. © 2020 John Wiley %26 Sons Ltd

aryl azide; crosslinker; microwave; phase-transfer catalyst; photoaffinity labeling; SNAr Benzene; Catalysts; Crosslinking; Irradiation; Microwave irradiation; Reagents; Sodium Azide; Synthesis (chemical); Click chemistry; Electron-withdrawing substituents; Halogenated benzenes; Mild temperatures; Phase transfer; Phase transfer catalysts; Photoaffinity labeling; Tetraethylammonium tetrafluoroborate; Sulfur compounds

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