1 H NMR ( 400 MHz , CDCl 3 ) : δ ppm : 9 . 73 ( t , J = 1 . 7 Hz , 1 H ) , 3 . 64 ( s , 3 H ) , 2 . 39 ( tt , J = 7 . 4 , 1 . 5 Hz , 2 H ) , 2 . 27 ( t , J = 7 . 6 Hz , 2 H ) , 1 . 59 ( m , 4 H ) , 1 . 27 ( m , 10 H )