corrinoids (cobalamines, corphyrins, corrins, vitamin B12 compounds)

https://doi.org/10.1351/goldbook.C01350
Derivatives of the corrin @N04256@, which contains four reduced or partly reduced pyrrole rings joined in a @M03662@ by three C01350-1.png groups and one direct carbon–carbon bond linking α positions.
C01350-2.png
Source:
PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1328 [Terms] [Paper]