Rifaximin Impurity 1

Smile: O=C([C@](O1)(O/C=C/[C@@H]([C@H]([C@H]2OC(C)=O)C)OC)C)C(C1=C(C)C3=O)=C(C3=C(O)C(NC(/C(C)=C\C=C\[C@H](C)[C@H](O)[C@@H](C)[C@@H](O)[C@H]2C)=O)=C4N5C=C6)C4=NC5=CC6=C