Benzophenone imine → 7-(Benzhydrylideneamino)-3-(4-chlorophenyl)-2-isopropyl-8-methoxy-chromen-4-one

Participants

Reaction Conditions

Reaction Steps

A stirred mixture of trifluoromethanesulfonic acid 3-(4-chlorophenyl)-2-isopropyl-8-methoxy-4-oxo-4H-chromen-7-yl ester (2.41 g, 5.05 mmol), 1,1′-bis(diphenylphosphino)-ferrocene (5.6 g, 10.1 mmol, 2 eq.), tris(dibenzylideneacetone)dipalladium (0) (3.08 g, 3.36 mmol, 0.665 eq.), sodium t-butoxide (0.58 g, 6.06 mmol, 1.2 eq.) and benzophenone-imine (1.1 g, 1.02 ml, 6.06 mmol, 1.2 eq.) in toluene (160 ml) is heated under reflux at 130° C. for 45 min. The reaction mixture is allowed to cool to room temperature and filtered through a pad of Celite filter aid. The Celite is washed with methylene chloride, and the filtrate is evaporated to dryness in vacuo to afford 7-(benzhydrylideneamino)-3-(4-chlorophenyl)-2-isopropyl-8-methoxy-chromen-4-one as a red oil. A stirred solution of the red oil in tetrahydrofuran (80 ml) is treated with 2M HCl solution (80 ml). After 30 min, the reaction mixture is basified with 17% ammonia solution and washed with ethyl acetate. The organic layer is dried over anhydrous magnesium sulfate and filtered, and the solvent is removed by evaporation in vacuo to afford a dark residue. This is purified by flash chromatography (cyclohexane/ethyl acetate=9:1) to afford the title compound.

Provenance & Evidence