Condensation of aminophenol with salicylic acidCondensation of aminophenol with salicylic acid
SyntheticPage 627
Published Jul 15, 2013
To 3,5-di-tert-butyl salicylic acid (2.03 g, 8.1 mmol) in a Schlenk vessel was added PPh3 (8.5 g, 33 mmol) and 2‑aminophenol (0.89 g, 8.1 mmol), and the atmosphere in the vessel was replaced with argon. Acetonitrile (~25 ml), and then triethylamine (4.5 ml, 45 mmol) were added, with stirring. CCl4 (7.8 ml, 81 mmol) was added dropwise over 4 hours. The mixture was stirred for 48 hours, after which time the solution was filtered, washed through with a little Et2O, which caused a further precipitation, this precipitate was also removed by filtration. The solvents were removed in vacuo, and the product extracted with hexane (3 × 100 ml). The combined extracts were dried in vacuo, and the pale yellow powder was purified by flash chromatography on a silica column, eluted with hexane-ethyl acetate (50:1), affording HL12 as a fine white powder (0.30 g, 11%) after removal of solvent.