1 H - NMR ( 400 MHz , CDCl 3 ) δ = 2 . 76 ( dd , 1 H , J 1 = 2 . 6 Hz , J 2 = 4 . 8 Hz ) , 2 . 91 ( t , 1 H , J = 4 . 5 Hz ) , 3 . 34 - 3 . 38 ( m , 1 H ) , 3 . 90 ( dd , 1 H , J 1 = 5 . 7 Hz , J 2 = 11 . 03 Hz ) , 4 . 21 ( dd , 1 H , J 1 = 2 . 93 Hz , J 2 = 11 . 02 Hz ) , 6 . 74 - 7 . 24 ( m , 4 H , Ph ) .