Talk:Corrin

Methylene groups
The methylene description is taken from http://www.chm.bris.ac.uk/motm/vitaminb12/structure.html without any consideration on what is shown in the figure. There is no need to distinguish between the two type of methylene groups (2 x =(CCH3)- vs 1 x =(CH)- ) which are technically BOTH methine groups if we do not show the methyl groups on the ring. Otherwise we have to use terms like methylmethine(?) vs methine --Kupirijo 09:04, 2 February 2007 (UTC)

CAS number
It's incorrect. The embedded link to CommonChemistry.org finds no such registered chemical. The CAS No 274-76-0 corresponds to Imidazo[1,2-a]pyridine in Sigma's catalog.150.135.165.27 (talk) 17:18, 11 September 2018 (UTC)