1 H - NMR ( 400 MHz , DMSO - d 6 ) : δ = 1 . 74 ( t , 2 H ) , 2 . 18 ( m , 4 H ) , 2 . 60 ( t , 4 H ) , 4 . 24 ( d , 2 H ) , 5 . 44 ( s , 2 H ) , 6 . 27 ( s , 2 H ) , 7 . 26 ( d , 2 H ) , 7 . 43 ( d , 2 H ) , 7 . 80 ( s , 1 H ) , 8 . 33 ( t , 1 H ) , 12 . 4 ( s , 1 H ) / Yield : 84 % ( 0 . 0502 mmol , 0 . 024 g )