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 …