Porphyrins with different numbers of β-propionate chains mimicking natural porphyrins were prepared via the 2+2 MacDonald type approach. Photodynamic activity against WiDr colon adenocarcinoma cells showed that activity is related to the number of β-propionate chains, with the derivatives with two carboxylic groups showing higher activity.
The synthesis of dipyrromethanes from pyrrole and arylglyoxylic acids in the presence of K2S2O8at 90 [Formula: see text]C is reported affording dipyrromethanes in very good yields. Unlike an excess pyrrole traditionally used in dipyrromethane synthesis, the current method uses a stoichiometric amount of pyrrole avoiding any use of Brønsted or Lewis acid. A gram scale synthesis of 5-phenyldipyrromethane is also achieved demonstrating potential scale up of dipyrromethanes using this method feasible. Subsequently, dipyrromethanes were converted to A4-tetraarylporphyrins also in the presence of K2S2O8at 90[Formula: see text]C. A direct synthesis of A4-tetraphenylporphyrin from excess pyrrole and phenylglyoxylic acid in the presence of K2S2O8 at 90[Formula: see text]C is also reported.