Two observations on a model of the biosynthesis of uroporphyrinogen III

Microbial Biosynthesis of B12-Like Compounds

“…(b) It can chelate a metal such as palladium. ( c) It has been proposed that the observed ready exchange of methylene hydrogens of octaethylporphyrinogen with solvent acetic acid is due to an acid-catalyzed tautomerization of the porphyrinogen to a transient form which has part of the corphin bond structure (289). Repeated tautomerizations would lead to a corphin structure.…”

Aminomethylated Pyrroles: Casting a Spotlight

“…Making use of the αmethylene group in the initial Mannich bases to provide the methine linker in porphyrins, this approach produces satisfactory yields of a mixture containing the corresponding porphin (76) (R = R 1 = H) and chlorin (77) (R = R 1 = H) as their magnesium complexes. Furthermore, under the appropriate conditions, an aminomethylated pyrrole was shown to produce porphyrinogen (80), a hexahydroporphyrin in which the four pyrrole rings are linked through methylene bridges [92]. The attempt to apply the same strategy to 3,4-diaryl-substituted pyrrole Mannich bases led only to porphins (76) (R = Ar, R 1 = H); the formation of the related chlorines can not be excluded, but their absence in the reaction mixture has been tentatively explained based on these compounds' high tendency to oxidize to porphins [30].…”

Chemie der α‐Aminonitrile 1. Mitteilung Einleitung und Wege zu Uroporphyrinogen‐octanitrilen

“…6.3. Ringoflnung von tic-20 zu rac-GIutamindinitril ( 29,00,29,05,30,37(3t,6CH2);54,64,55,48,56,11 (3~,6C); 91,72(~,115,53(~,2CN); 168,36(~,2C02); 28,93,30,34(3t,6CH2);54,75,55,48,56,16(3s,6C); 91,63(s,2C-O); 115,86(~,2CN);.l68,34(~,2C02); 177,88 30,68(6t,6CH2);53,78,54,29,54,68,54,89(4s,4C);55,40(s,2C); 91,76,91,91(2s,2C-O); 115,72, 116, Fig.6): 3670w, 3405s, 3340m, 3020s,2940m, 2867iv, 2250s, 2235 (sh), 1623m (br. ), 1446s, 1424s, 1368w, 1310m, Fig.…”

“…her. fur C,,H,,N,O: C 76,78,H 5,64,N 11.19;gef. : C 76,72,H 5,56,N 11,[13][14][15][16][17][18][19][20] durch Umsetzung m i t .…”

“…Fur die Isolierung, Charakterisierung und Bearbeitung dieser Verbindungen entscheidend envies sich deren Eigenschaft, an der Luft zwar autoxidationsempfindlich zu sein, dies jedoch in merklich geringerem Masse als es z. B. fur Octaethylporphyrinogen[78]…”