High-yield synthesis of a chiroporphyrin by hydrogen bond-directed cyclisation
Abstract
A new chiroporphyrin is prepared in 60% yield using complementary intramolecular hydrogen-bonding interactions between N-acylurea substituents to direct the cyclisation of the tetrapyrrolic intermediate; similar hydrogen-bond assistance by carboxylic acid functions is suggested for cyclisation of hydroxymethylbilane to uroporphyrinogen I.