1 H NMR ( 300 MHz , CDCl 3 ) δ 1 . 56 - 1 . 68 ( m , 2 H ) , 1 . 76 ( m , 2 H ) , 1 . 90 - 2 . 03 ( m , 4 H ) , 2 . 17 ( s , 3 H ) , 2 . 27 ( br t , 2 H , J = 6 . 6 Hz ) , 2 . 43 ( m , 1 H ) , 2 . 65 ( s , 3 H ) , 2 . 82 ( m , 2 H ) , 4 . 39 ( br t , 2 H , J = 7 . 3 Hz ) , 6 . 96 ( m , 1 H ) , 7 . 23 ( m , 1 H ) , 7 . 31 - 7 . 36 ( m , 4 H ) , 7 . 40 ( br s , 1 H ) , 7 . 50 ( m , 2 H ) , 7 . 83 ( m , 1 H ) , 8 . 02 ( dd , 1 H , J = 8 . 0 , 2 . 3 Hz ) , 8 . 90 ( d , 1 H , J = 2 . 1 Hz ) ; MS ( m / e , M +): 467 ( M +), 250 , 231 , 70 .