1 H NMR δ 1 . 55 - 1 . 75 ( br m , 2 H ) , 1 . 85 - 1 . 95 ( br m , 2 H ) , 2 . 4 - 2 . 5 ( br m , 2 H ) , 2 . 7 - 2 . 85 ( br m , 2 H ) , 3 . 3 - 3 . 5 ( br m , 2 H ) , 3 . 8 ( m , 2 H ) , 6 . 9 ( s , 1 H ) , 7 . 0 ( s , 1 H ) , 7 . 3 ( m , 2 H ) , 7 . 45 ( s , 1 H ) , 7 . 5 ( m , 2 H ) , 9 . 6 ( t , 1 H ) ; MS m / z 334 . 3 ( M + H ) , 266 . 1 ( M - C 3 H 3 N 2 · )