1 H NMR δ 1 . 8 - 2 . 0 ( m , 2 H ) , 3 . 4 - 3 . 5 ( br m , 2 H ) , 3 . 6 ( s , 3 H ) , 3 . 7 ( s , 6 H ) , 3 . 9 - 4 . 0 ( m , 2 H ) , 6 . 65 ( m , 2 H ) , 6 . 85 ( s , 1 H ) , 7 . 2 ( s , 1 H ) , 7 . 6 ( s , 1 H ) , 7 . 7 ( br s , 1 H ) , 9 . 4 ( s , 1 H ) ; MS m / z 351 . 3 ( M + H ) , 283 . 2 ( M - C 3 H 3 N 2 · )