Wikipedia:Reference desk/Archives/Science/2022 February 10

= February 10 =

What's the record for "highest number of rings in an active ingredient molecule"?
Amongst drugs where the active ingredient is an exact compound and not a mixture. Sagittarian Milky Way (talk) 20:49, 10 February 2022 (UTC)
 * Are we including macro-molecule therapies, such as ones using a protein? A protein is technically a single molecule, and it can have a LOT of rings. Also, are we talking aromatic or not? --OuroborosCobra (talk) 21:01, 10 February 2022 (UTC)
 * The Pfizer-BioNTech COVID-19 vaccine has an RNA sequence with 4284 nucleotides, each with several rings. --Amble (talk) 21:48, 10 February 2022 (UTC)
 * Proteins made of amino acids, several of which (proline, phenylalanine, histidine and tyrosine) contain 1 ring, and one (tryptophan) contains two. While insulin, a necessary medication for people with diabetes, is a relatively small protein (only 51 amino acids), the broad class of proteins known as interferons can get MUCH larger, and many have therapeutic uses. -- Jayron 32 16:22, 11 February 2022 (UTC)
 * While peptides/proteins are clearly going to set the record,, maybe you meant to exclude them. There is then a different problem: you could go through Category:World Health Organization essential medicines and look for those with a large number of rings. But how many will you count for compounds like vancomycin which has one very large ring, if you choose to take the maximal periphery, plus numerous smaller rings? Or morphine with its interlocking bridged system? Mike Turnbull (talk) 16:43, 11 February 2022 (UTC)
 * How many rings or cycles does vancomycin have in the most common counting convention? 11? If they counted rings that contained rings then olympicene would have a lot more than 5 rings. Sagittarian Milky Way (talk) 19:05, 11 February 2022 (UTC)
 * Yes, I was pointing out that graph theory, as applied to chemicals is relevant. If you read International Chemical Identifier, you'll see why I chose morphine as an example. Your question interested me: having thought about it, I moved on to wonder which drug had the most ring bonds, as a proportion of all its bond (or maybe its non-CH bonds). That number, expressed as a %, can reach 100% for buckminsterfullerene (not a medicine!) and it is certain that the record-holder won't be one of the polymer-like materials of vaccines, peptides etc. makes a perfectly good point below but thinking about questions like this is good for my aging brain. Mike Turnbull (talk) 13:14, 12 February 2022 (UTC)
 * As a percent of all or non-CH bonds is also interesting, if I had the last Physicians Desk Reference I could check some each day till I found the answers, at least for the subset of drugs that both show the structure sufficiently and weren't removed for obsolescence or missing the deadline for inclusion (I don't know if drugs that have been obsolete for many years are still listed). Sagittarian Milky Way (talk) 15:16, 12 February 2022 (UTC)
 * You could instead start from Wikipedia entries that use Template:Infobox drug, of which there are apparently about 8000 which are not mixtures. Amantadine is a drug with a carbon framework of entirely ring bonds but it may not be the record holder even on the % criterion because of its attached -NH2 group. Good luck.... Mike Turnbull (talk) 18:06, 12 February 2022 (UTC)
 * Phencyclidine has 100% of its non-H atoms in rings, but amantadine beats it in terms of percentage of the non-C–H bonds that are ring-bonds. DMacks (talk) 02:42, 14 February 2022 (UTC)


 * The problem with a question like this is not "Is there a record?" Given that there are a finite (extremely large number, but still finite) number of different therapeutic compounds out there, there is going to be one "most" of any random property one could care to name.  That such a "most number of rings record" exists does NOT mean that anyone has ever thought to note such a record before.  Without sources to confirm that such a record has been noted before now, it is essentially impossible we're going to hit on that record by guessing random molecules we've heard about.  Questions of this type are unanswerable, not necessarily because there isn't an answer, just because no one has ever figured it out, and we're for sure not going to reliably create that answer here.   -- Jayron 32 19:16, 11 February 2022 (UTC)
 * You may wish to consult Category:Heterocyclic compounds with 7 or more rings. However I may not have all the compounds that could be there categorised. And I have not included biological macromolecules. DNA and RNA with their purines and bases have numerous rings, but not fused together. A seven ring heterocycle has seven rings interconnected, so you have to cut 7 bonds to turn this to a connected branching molecule. But for the category, it may additionally include other rings with lesser connection. Graeme Bartlett (talk) 02:24, 13 February 2022 (UTC)