1 H NMR δ 1 . 7 - 1 . 9 ( m , 2 H ) , 2 . 9 - 3 . 1 ( m , 2 H ) , 3 . 7 ( 2 s , 6 H ) , 3 . 9 - 4 . 0 ( m , 2 H ) , 6 . 1 ( t , 1 H ) , 6 . 7 ( s , 2 H ) , 6 . 8 ( s , 1 H ) , 7 . 15 ( d , 2 H ) , 7 . 6 ( s , 1 H ) , 8 . 2 ( s , 1 H ) ; MS m / z 321 . 2 ( M + H ) , 253 . 3 ( M - C 3 H 3 N 2 · )