Synthesis of 2-arylbenzoxazoles via the palladium-catalyzed carbonylation and condensation of aromatic halides and o-aminophenols
作者:Robert J. Perry、B. David Wilson、Richard J. Miller
DOI:10.1021/jo00036a025
日期:1992.5
A new synthetic method is reported in which 2-arylbenzoxazoles can be prepared by the palladium-catalyzed condensation of aryl halides with o-aminophenols followed by dehydrative cyclization. This method is tolerant of a wide variety of functional groups on either aromatic ring and gives good to excellent yields of products. An aliphatic vicinal amino alcohol gave a bis-acylated product as well as a chlorine-containing product with only a small amount of the desired 2-aryloxazole being formed. Methyl iodide and benzyl bromide gave only alkylated products.
A green route for the synthesis of 2-substituted benzoxazole derivatives catalyzed by Al3+-exchanged K10 clay
A new, simple, and efficient protocol is developed for the synthesis of 2-substituted benzoxazole derivatives through N-C-O bond formation using Al3+-exchanged K10 clay (Al3+-K10) as catalyst. A wide range of benzoxazole derivatives are synthesized in high yields without affecting many functional groups. Hot filtration experiments showed the absence of metal leaching and catalyst can be reused for five times with only a slight decrease in yield. (C) 2013 Elsevier Ltd. All rights reserved.
WAGNER G.; EPPNER B., PHARMAZIE, 1980, 35, NO 5-6, 285-288
An amido-directing regioselective and nucleophilic halogenation reaction of electron-rich amidophenols was realized in the presence of Fe(III) reagents. Halides could be sequentially introduced to specific positions to form mono-, di- and mixed di- halogenated amidophenols mostly in one-pot manner.