1 H NMR ( 300 MHz , CDCl 3 ) δ 1 . 62 - 1 . 76 ( 1 H , m ) , 1 . 81 - 1 . 93 ( 1 H , m ) , 2 . 12 - 2 . 26 ( 2 H , m ) , 2 . 41 - 2 . 53 ( 2 H , m ) , 3 . 36 - 3 . 44 ( 2 H , m ) , 4 . 61 - 4 . 72 ( 3 H , m ) , 6 . 56 ( 1 H , t , J = 6 . 8 Hz ) , 6 . 82 ( 2 H , d , J = 8 . 7 Hz ) , 7 . 16 ( 1 H , dd , J = 6 . 8 , 1 . 5 Hz ) , 7 . 45 ( 1 H , dd , J = 7 . 2 , 1 . 5 Hz ) , 7 . 52 ( 2 H , d , J = 8 . 7 Hz ) .