7-bromochroman-4-one

Used as a intermediate for  R & D.

7-Bromochroman-4-one was synthesized by hydrogenation addition of 7-Bromo-benzopyrone catalyzed by Wilkinson's catalyst Rhodium( Ⅰ) tris( triphenylphosphine) chloride[Rh( PPh3)3Cl]. The structure was confirmed by1 H NMR and MS. The optimum reaction conditions for synthesizing 7-Bromochroman-4-one were as follows: 5 0. 329 mol,ethanol as the solvent,c( 5) =0. 4 mol·L- 1,4% mol Rh( PPh3)3Cl as the catalyst,under 0. 3 MPa of hydrogen pressure,at 70℃ for 20 h,the yield was 79. 8%.