text: Indoleamine 2,3-dioxygenase (IDO) be the name,
  A heme dioxygenase involved in immune escape, it's the same.
  Fightin' diseases like cancer, that's its game,
  Pathological pathways, it aim to tame.
  
  Synthesis and structure-activity relationships, we explore,
  Novel IDO inhibitors, we adore.
  Indol-2-yl ethanone scaffold, the core,
  Breakin' barriers, openin' new doors.
  
  In vitro and in vivo, we evaluate,
  Biological activities, we don't hesitate.
  Micromolar range, compounds demonstrate,
  IC(50) values, we calculate.
  
  Indole ring, 5- and 6-positions, we tweak,
  Small substituents, no limits, no peak.
  Indole N-methylation, aromatic side chain, we seek,
  All well tolerated, no need to critique.
  
  Linker with iron coordinating group, it's a must,
  For biological activity, a prerequisite we trust.
  Virtual screening results, they adjust,
  Confirming our findings, no need to discuss.