The Chemistry of Pyrrolic Compounds. LXVIII. 13'- and 15'-Methyl Analogs of Deoxophylloerythroetioporphyrin (dpep)

Abstract

A new synthesis of the 13′-methyl (1a) analogue of dpep is described commencing with the methylation of phylloerythroetioporphyrin (1d) with subsequent reduction of the derived tertiary alcohol. The availability of this synthetic material has allowed the presence of this petroporphyrin as its nickel complex to be confirmed in the Julia Creek oil shales. The presence of an isomer of this petroporphyrin has been noted in the same deposit, and the structure of this novel fossil porphyrin has been confirmed as the 15′-methyl analogue (1b) of dpep by a synthesis commencing from the 15′-oxoporphyrin (1e). In addition, the 15′- and 13′-methyl analogues of dpep have been synthesized by cylization of appropriately substituted propenyl- and isopropenyl-porphyrins respectively. The origin of these two petroporphyrins is discussed.