Monopyrrolic Natural Compounds Including Tetramic Acid Derivatives

Abstract

Pyrrole was discovered in the coal tar by Friedlieb Ferdinand Runge (1794–1867) in May 1834. Only 24 years later — in 1858 — it was obtained in a pure state by Thomas Anderson (1819–1874) by distillation of bone oil. The actual structure of pyrrole, which was suggested by Adolf von Baeyer (1835–1917) in 1870 on the basis of his work on the elucidation of the structure of indigo (1), was proved later (1877) by synthesis by Chichester A. Bell (2). The later development of synthetic methods for the preparation of pyrrole derivatives by Ludwig Knorr in 1884 and Carl Ludwig Paal in 1885 paved the way for Hans Fischer’s overwhelming work on the synthesis of naturally occurring pyrrolic pigments, which culminated in 1929 with the total synthesis of haemin. The relationship of the latter with pyrrole had been already established, at the beginning of the 20th century, by the Russian physician Marceli Nencki (1847–1901) and by William Küster (1863—1929). On the other hand, Leon Pavel Teodor Marchlewski (1869–1946), in collaboration with Nencki, proved in 1901 that haemin and chlorophyll are structurally related. The enormous biological significance of the tetrapyrrolic pigments — the so-called pigments of life (3) — delayed manifestly the search for more simple derivatives of pyrrole in nature. Of great significance, therefore, was the observation made by Sachs in 1931 that the urine of patients affected by acute porphyria gives a positive Ehrlich reaction, which is characteristic for pyrrole and its derivatives (4).