Corrin

Corrin

Identifiers
CAS Number	262-76-0
ChEBI	CHEBI:33221
ChemSpider	16736705
Jmol interactive 3D	Image
PubChem	6438343
InChI InChI=1S/C19H22N4/c1-3-14-10-16-5-7-18(22-16)19-8-6-17(23-19)11-15-4-2-13(21-15)9-12(1)20-14/h9-11,18-19,22H,1-8H2/b12-9-,15-11-,16-10- Key: WUPRCGRRQUZFAB-DEGKJRJSSA-N InChI=1/C19H22N4/c1-3-14-10-16-5-7-18(22-16)19-8-6-17(23-19)11-15-4-2-13(21-15)9-12(1)20-14/h9-11,18-19,22H,1-8H2/b12-9-,15-11-,16-10- Key: WUPRCGRRQUZFAB-DEGKJRJSBL
SMILES N=1C=4CCC=1\C=C2/NC(CC2)C\5CC/C(C=C3\CC/C(=N3)/C=4)=N/5
Properties
Chemical formula	C19H22N4
Molar mass	306.40478
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Corrin is an heterocyclic compound. It is the parent macrocycle related to substituted derivative that is found in vitamin B₁₂. Its name reflects that it is the "core" of vitamin B₁₂ (cobalamins).^[1]

Coordination chemistry

Upon deprotonation, the corrinoid ring is capable of binding cobalt. In vitamin B₁₂, the resulting complex also features a benzimidazole-derived ligand, and the sixth site on the octahedron serves as the catalytic center.

The corrin ring resembles the porphyrin ring, which occurs in hemoglobin. Both feature four pyrrole-like subunits organized into a ring. In contrast to porphyrins, corrins lack one of the carbon groups that link the pyrrole-like units. Thus the large ring has 19 carbons, whereas porphyrins have 20. Also, the pyrrole-like rings in corrin are fully saturated "edge-carbon" centers. Because of the high number of sp³ carbon centers, corrins are more flexible than porphyrins and are not as flat. They do not have a full conjugated character around the entire ring. Instead, the ring has a kind of "3/4" conjugation.

Corroles (octadehydrocorrins) are fully aromatic derivatives of corrins.

References

1. Nelson, D. L.; Cox, M. M. "Lehninger, Principles of Biochemistry" 3rd Ed. Worth Publishing: New York, 2000. ISBN 1-57259-153-6.