Showing structure for 3-methyl-n-(2-{4-thia-6,9,19-triazapentacyclo[10.7.1.0³,⁷.0⁸,²⁰.0¹³,¹⁸]icosa-1,3(7),5,8(20),9,11,13,15,17-nonaen-2-yl}ethyl)but-2-enimidic acid