1 H - NMR ( 300 MHz , CD 3 OD ) σ 2 . 46 ( s , 3 H ) , 2 . 67 ( s , 3 H ) , 2 . 73 ( s , 3 H ) , 7 . 36 ( d , 1 H , J = 7 . 5 Hz ) , 7 . 42 ( dd , 1 H , J = 7 . 5 , 7 . 7 Hz ) , 7 . 78 ( d , 1 H , J = 7 . 7 Hz ) , 7 . 86 ( s , 1 H ) ;