1 H NMR ( 300 MHz , CDCl 3 ) δ NMR ( 300 MHz , CDCl 3 ) δ 1 . 65 - 1 . 81 ( m , 4 H ) , 1 . 90 - 2 . 00 ( m , 4 H ) , 2 . 15 ( s , 3 H ) , 2 . 25 ( t , 2 H ) , 2 . 45 ( m , 1 H ) , 2 . 82 ( br - d , 2 H ) , 4 . 30 ( t , 2 H ) , 6 . 92 ( d , 1 H , J = 6 . 8 Hz ) , 7 . 24 - 7 . 53 ( m , 9 H ) , 7 . 69 - 7 . 79 ( m , 3 H ) ; MS ( m / e , M +): 487