C₂₁H₂₆N₄O₃

The molecular formula C₂₁H₂₆N₄O₃ (molar mass: 382.464 g/mol) may refer to:

• N-Desethylprotonitazene
• N-Desethylisotonitazene, a designer drug with opiod effects
• Metonitazene, an analgesic compound