Bilane

In organic chemistry, bilane is a compound with the formula C
19
H
20
N
4
or [(C
4
H
4
N)−CH
2
−(C
4
H
3
N)−]
2
CH
2
. It is a tetrapyrrole, a class of compounds with four independent pyrrole rings. Specifically, the molecule can be described as four pyrrole molecules C
4
H
5
N
connected in an open chain by three methylene bridges −CH
2
at carbons adjacent to the nitrogens, replacing the respective hydrogens.[1]

Bilane
Names
IUPAC name
2-(1H-Pyrrol-2-ylmethyl)-5-[[5-(1H-pyrrol-2-ylmethyl)-1H-pyrrol-2-yl]methyl]-1H-pyrrole
Other names
Bilinogen; Tetrapyrrolotrismethane
Identifiers
3D model (JSmol)
8008279
ChEBI
ChemSpider
Properties
C19H20N4
Molar mass 304.397 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

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]

Reactions

Upon treatment with aldehydes, bilanes may cyclize to give porphyrinogens and various open or closed oligomers and polymers.[2]

In living organisms, the biosynthesis of all natural porphyrins proceeds through the bilane preuroporphyrinogen, 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). Also, the catabolism of hemoglobin in humans produces bilirubin, another linear tetrapyrrole that is a partially oxidized bilane.

References

  1. Gerard P. Moss (1988). "Nomenclature of Tetrapyrroles. Recommendations 1986". European Journal of Biochemistry. 178 (2): 277–328. doi:10.1111/j.1432-1033.1988.tb14453.x. PMID 3208761.
  2. Lindsey, J. S. (2010). "Synthetic Routes to meso-Patterned Porphyrins". Accounts of Chemical Research. 43 (2): 300–311. doi:10.1021/ar900212t. PMID 19863076.
  3. Claudia 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
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