1 H NMR ( 400 MHz , DMSO - d 6 ) δ 9 . 98 ( s , 1 H ) , 9 . 52 ( s , 1 H ) , 8 . 83 ( s , 1 H ) , 7 . 08 ( d , J = 2 . 0 Hz , 1 H ) , 7 . 01 ( dd , J = 8 . 4 , 2 . 0 Hz , 1 H ) , 6 . 94 ( d , J = 8 . 4 Hz , 1 H ) , 5 . 79 ( dd , J = 10 . 4 , 4 . 8 Hz , 1 H ) , 4 . 30 - 4 . 17 ( m , 2 H ) , 4 . 02 ( q , J = 6 . 8 Hz , 2 H ) , 3 . 74 ( s , 3 H ) , 3 . 01 ( s , 3 H ) , 2 . 21 ( s , 3 H ) , 1 . 32 ( t , J = 6 . 8 Hz , 3 H ) . LCMS : [ M + H ] + = 461 . 9 .