But \(-2-\) ene \(-1, 4-\) dioic acid
$\,{H_3}C\, - \,\,\mathop C\limits^{\mathop {||}\limits^O } \,\, - \,\,\mathop C\limits^{\mathop |\limits^{OH} } H\,\, - \,\,\mathop C\limits^{\mathop |\limits^{N{O_2}} } H\,\, - \,\,C{O_2}H$