Pyrroles and related compounds. Part XXVIII. β-Keto-esters in the porphyrin series

Abstract

Porphyrin carboxylic acids are converted into the corresponding β-keto-esters by reaction between the acid chlorides and t-butyl methyl malonate, followed by treatment with trifluoroacetic acid. Iodine in methanol reacts with the magnesium chelate of the keto-ester anion derived from rhodoporphyrin-XV dimethyl ester, giving the chelate of 10-methoxyphaeoporphyrin-a5 dimethyl ester. The significance of these results in relation to the biosynthesis of chlorophyll is discussed.