Presented is a quick and efficient method for the insertion of first-row transition metal acetates into 5,10,15,20-tetraphenyl porphyrin, utilizing Soxhlet extraction for the removal of the acetic acid by-product. High yields (>90%) and purity are achieved without requiring chromatographic purification. Basic Mn(III) and Fe(III) acetate may be used, as well as hydrated Co(II), Ni(II), and Cu(II) acetates as starting materials. In the case of Fe, an initial mixture of Fe(TPP)OAc and [Fe(TPP)]2O is formed, which can be quantitatively converted to Fe(TPP)OAc by treatment with acetic acid. The crystal structure of Fe(TPP)OAc is reported, and spectral data for all compounds is presented, including a correction of the literature UV–Vis data for Fe(TPP)OAc. Attempted metalation with basic Cr(III) acetate yielded a mixture of Cr(TPP)OAc and the oxo-bridged dimer. The latter cannot be converted to the desired acetate. No reaction occurred with vanadyl or titanyl acetate under the conditions used.Graphical abstractA new high-yielding synthetic procedure for the metalation of porphyrins is described. First-row transition metal acetates may be inserted into 5,10,15,20-tetraphyenyl porphyrin utilizing Soxhlet extraction for the removal of the acetic acid by-product. Basic Mn(III) and Fe(III) acetate may be used, as well as hydrated Co(II), Ni(II), and Cu(II) acetates as starting materials. High yields (>90%) and purity are achieved without requiring chromatographic purification.Highlights► A convenient method for the metalation of porphyrins. ► The crystal structure of FeIII(TPP)OAc. ► Corrected UV–Vis data for FeIII(TPP)OAc.

The reaction of free base or Ni(II) complex secochlorin bisaldehydes 4H2 and 4Ni regenerates the ultimate starting material of the bisaldehydes, meso-tetraphenylporphyrin 2H2 and 2Ni, respectively. Depending on the reaction conditions employed (hydrazine hydrate in pyridine at reflux or hydrazine hydrate activated with sulfur in the presence of aqueous NaOH at ambient temperature), either porphyrin 2H2 is formed together with known dihydroxymorpholinochlorin 9H2 or known 2-hydroxychlorin 8H2. Two different reaction pathways for the hydrazine reaction can be derived, either involving the formation of a meso-tetraphenyl-1,4,5-triazepinoporphyrin that loses spontaneously N2 or a Wolff–Kishner-type pathway that also involves an intramolecular aldol-type reaction. Neither reaction is synthetically useful but both highlight in an impressive fashion the high thermodynamic stability of porphyrins. They also bring the ‘breaking and mending of porphyrin’ strategy to its ultimate conclusion by regenerating the starting porphyrin.Reaction of known secochlorin bisaldehyde–made from meso-tetraphenylporphyrin (TPP) by two-step oxidation–with hydrazine induces a reductive coupling reaction to regenerate TPP, presumably via excision of N2 from the elusive seven-membered ring intermediate, meso-tetraphenyl-1,4,5-triazepinoporphyrin