Porphyrins. VIII. A stepwise synthesis of porphyrins

Abstract

1,2,3,4,5,6,7,8-Octanlethylporphin and α,γ,1,2,3,4,5,6,7,8-decamethylporphin have been prepared by the acid-catalysed condensation of 5,5'-diformyl-3,4,3',4'-tetramethylmethanes (VI; R = H or CH₃) with the corresponding dicarboxylic acid derivatives (VII), followed by oxidation. For the preparation of meso-substituted porphyrins the method seems to be more satisfactory than those already in the literature, and can be developed further.