1 H NMR ( 300 MHz , DMSO - d 6 ) δ 1 . 25 ( 6 H , d , J = 6 . 1 Hz ) , 1 . 61 - 1 . 81 ( 3 H , m ) , 1 . 84 - 2 . 07 ( 1 H , m ) , 3 . 17 - 3 . 30 ( 2 H , m ) , 3 . 36 - 3 . 55 ( 2 H , m ) , 3 . 64 - 3 . 72 ( 1 H , m ) , 3 . 72 - 3 . 94 ( 2 H , m ) , 4 . 57 ( 1 H , quin , J = 6 . 1 Hz ) , 6 . 76 - 6 . 90 ( 2 H , m ) , 7 . 02 - 7 . 15 ( 2 H , m ) .