By R. CHONG,? P. 5. CLEZY,~. AJ LIEPA,? and AW NICHOL~. ... Summary The preparation of a number of 5,5'-diformyldipyrrylmethanes is described using benzoyl chloride-N,N-dimethylformamide as the formylating mixture. ... Recent approaches192 to the synthesis of porphyrins have been concentrated on methods which allow the preparation of completely unsymmetrical molecules. These procedures involve cyclization of an intermediate linear tetrapyrrole. ...