Synthesen der Chlorophyllporphyrine Rhodo‐ und Pyrroporphyrin, sowie des Pyrro‐ätioporphyrins

Abstract

Rhodo-und Pyrroporphyrin entstehen beim alkalischen Abbau des Chlorophylls. Pyrroporphyrin wurde durch Synthese als eine Tetramethyl-diathylporphin-monopropionsaure erkannt. Theoretisch sind 24 Isomere mgglich, von denen einige3 bereits synthetisiert sind (2. B. Nr. 21). Bei Rhodoporphyrin ist die gleiche Anzahl von Isomeren denkbar, denn es ist ein carboxyliertes Pyrroporphyrin. Wenn man in Formel 21 an die Stelle des R'asserstoffatoms eine Carboxylgruppe setzt, so haben wir die Formel des Rhodoporphyrins (Rh 21) vor uns, dessen Synthese bereits beschrieben wnrde.

Chlorophyll.

“…As this might occur in three ways, theory predicts twenty-four isomeric pyrroporphyrins and the same number of rhodoporphyrins, since it was highly probable, through the transition from rhodoporphyrin to pyrroporphyrin with splitting off of carbon dioxide, that in place of the free methine group in pyrroporphyrin a nuclear carboxyl group was present in rhodoporphyrin. The synthesis of certain pyrro-and rhodo-porphyrins completely confirmed this assumption (46,6,5,47).…”

“…If both propionic acid residues are decarboxylated to ethyl groups, the formulas of the two etioporphyrins result. The proof was obtained by synthesis (6,18,47). Strictly speaking, moreover, the etioporphyrin of blood pigment should be considered to be, not the carboxyl-free mesoporphyrin, but the carboxyl-free protoporphyrin, whose synthesis was recently achieved (25).…”

Cyclizations of terminally substituted a,c-biladiene salts to give meso-substituted porphyrins

“…The catalyst was removed by filtration through Celite and the filtrate was evaporated to give a residue which was crystallized from THFhexane to give a white powder (3 g, 98%), m.p. 1 was treated with sodium hydrogen carbonate (3.4 g) in water (35 ml) and warmed to 60 "C before addition of a solution of iodine (3.4 g) and potassium iodide (5.5 g) in methanol (45 ml) and water (11 ml) with stirring at a rate such that no permanent colouration developed. Water (40 ml) was then added and the mixture was stirred for a further 1 h. It was then cooled and extracted with dichloromethane (2 x 100 ml) and the extract washed with water (3 x 50 mi), dried (Na,SO,), and evaporated to dryness.…”

Recent Progress in Determining the Chemical Structure of Chlorophyll.

“…Fischer developed methods not only for synthesizing substituted pyrroles, but for combining these into dipyrrylmethenes, and further for uniting two such methenes to form porphyrins (19,36). In this way several series of isomeric porphyrins were obtained, and these included porphyrins identical with rhodoporphyrin (V a), pyrroporphyrin (V b), and phylloporphyrin (V c).…”