1 H NMR ( 400 MHz , CD 3 OD ) : δ 7 . 30 ( m , 1 H ) , 7 . 16 ( m , 1 H ) , 6 . 95 ( m , 1 H ) , 5 . 10 ( m , 1 H ) , 4 . 64 ( m , 1 H ) , 4 . 29 ( d , 2 H ) , 4 . 02 ( d , 2 H ) , 3 . 61 ( s , 1 H ) , 2 . 87 ( d , 2 H ) , 2 . 70 ( s , 1 H ) , 2 . 65 ( m , 1 H ) , 1 . 93 ( s , 3 H ) , 1 . 74 ( s , 2 H ) , 1 . 64 ( m , 3 H ) , 1 . 47 ( m , 3 H ) , 1 . 31 ( m , 3 H ) .