Synthesis of pyrrole derivatives related to the uroporphyrins.

Abstract

The biosynthesis of tetrapyrroles is briefly discussed and the important intermediates for chemical synthesis of these compounds are derived by valuable new methods. -- Desulfurization of the pyrrole thiolesters was investigated, and the column reaction was introduced to improve the yield of the products. -- Pyrrole aldehydes, hydroxymethyl pyrroles, and methyl pyrroles could be obtained from the corresponding pyrrole thiolesters in fairly good yields. -- The hydroxymethyl group on pyrrole ring is easily converted to methyl group through chloromethyl group. Both β-hydroxymethyl pyrroles and β-chloromethyl pyrroles are easily converted to β, β¹-dipyrromethanes in acidic medium. -- N-H stretching of α-carbethoxydipyrromethanes is very similar to that of α-carbethoxypyrroles, and shows strong intermolecular hydrogen bonding in nonpolar solvents. α, α¹-Dipyrromethanes which have adjacent oarbethoxy groups show intramolecular hydrogen bonding where as β, β¹-dipyrromethanes do not. -- Infrared, ultraviolet and nuclear magnetic resonance spectra are given for all the new compounds.