1,5,7‐Triazabicyclo[4.4.0]dec‐5‐en als Reaktionsmedium: Präparativ ergiebige einstufige Herstellung von Etioporphyrin aus Protoporphyrin

1,5,7‐Triazabicyclo[4.4.0]dec‐5‐ene as Reaction Medium: An Efficient One‐Step Formation of Etioporphyrine from Protoporphyrine Heating the commercially available protoporphyrine (4) in molten 1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene (TBD) at 200° for 4 h under exclusion of O2 produces etioporphyrine (6) in 60–70% yield by bisdecarboxylation and concomitant reduction of the two vinyl groups. Mesoporphyrine (5) is bisdecarboxylated to 6 in over 80% yield under these conditions in TBD as well as in DBU as the reaction medium.