1 H NMR ( 400 MHz , chloroform - d 1 ) δ = 7 . 54 ( s , 4 H ) , 7 . 35 ( d , J = 4 . 4 Hz , 1 H ) , 6 . 88 ( d , J = 4 . 4 Hz , 1 H ) , 4 . 80 - 4 . 77 ( m , 1 H ) , 4 . 02 ( dd , J = 9 . 2 , 9 . 2 Hz , 1 H ) , 3 . 89 - 3 . 79 ( m 4 H ) , 3 . 69 - 3 . 62 ( m 1 H ) , 3 . 49 - 3 . 43 ( m , 2 H ) , 2 . 79 ( s , 3 H )