In organic chemistry, bilane is a compound with the formula C19H20N4 or [(C4H4N)−CH2−(C4H3N)−]2CH2. It is a tetrapyrrole, a class of compounds with four independent pyrrole rings. Specifically, the molecule can be described as four pyrrole molecules C4H5N connected in an open chain by three methylene bridges−CH2− at carbons adjacent to the nitrogens, replacing the respective hydrogens.[1]
The name is also used for the class of compounds formally derived from bilane proper by replacement of some additional hydrogen atoms by various functional groups. Natural bilanes usually have side chains substituted on the two carbons in each pyrrole ring that are not adjacent to the nitrogens. Artificial bilanes may be substituted on the bridging carbons (called meso positions).[2]
The parent (unsubstituted) bilane is difficult to prepare and unstable,[3] but substituted derivatives are synthesized by most living organisms as intermediates in the synthesis of natural porphyrins. Substituted bilanes may also be the starting point for the synthesis of artificial porphyrins.[2][3]
In living organisms, the biosynthesis of all natural porphyrins proceeds through the bilane, hydroxymethylbilane, which is produced from four molecules of the monomer porphobilinogen, and then converted to the closed tetrapyrrole uroporphyrinogen III (or, in certain metabolic disorders, into uroporphyrinogen I).[4]
123Lindsey, J. S. (2010). "Synthetic Routes to meso-Patterned Porphyrins". Accounts of Chemical Research. 43 (2): 300–311. doi:10.1021/ar900212t. PMID19863076.
12Claudia Ryppa, Mathias O. Senge, Sabine S. Hatscher, Erich Kleinpeter, Philipp Wacker, Uwe Schilde, and Arno Wiehe (2005): "Synthesis of Mono- and Disubstituted Porphyrins: A- and 5,10-A2-Type Systems". Chemistry, A European Journal, volume 11, issue 11, pages 3427-3442. doi:10.1002/chem.20050000
↑Battersby, Alan R. (2000). "Tetrapyrroles: The pigments of life". Natural Product Reports. 17 (6): 507–526. doi:10.1039/b002635m. PMID11152419.
