Porphyrin prebiotic synthesis

There have also been claims for a prebiotic synthesis of porphyrins. An electric discharge applied to a gaseous mixture of methane, ammonia, and water gives large yields of formaldehyde, small amounts of pyrrole, and tiny amounts of porphyrin. More efficient syntheses of porphyrins, especially those related to protoporphyrins and uroporphyrins, seem likely. One possibility has been demonstrated by Albert Eschenmoser, who managed to synthesise a mixture of porphyrins in the absence of oxygen and water, from a-amino nitriles using montmorillonite clay as a catalyst. ... 

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