Chemical names: IUPAC names and Nonsensical nomenclature

capric acid

Kat Day wrote this summer about nonsensical nomenclature: "The name wasn’t in my dictionary, nor the index of the few expensive textbooks I’d scraped together the funds to buy". Day is talking here about capric acid (GHVNFZFCNZKVNT-UHFFFAOYSA-N).

That sounds so familiar: both looking up facts, and collecting some second hand books. I found myself in the same situation in 1993-1994 when I started my chemistry degree. We did not have smartphones yet either, and even the Internet (still with a capital at the time) was just opening up (I got my access in spring 1994). Trivial names were bugging me too, and IUPAC nomenclature was the only thing where one would have a guess are figuring out the structure.

Day continues: "And non-systematic names can be practical. Take glucose. We all know what it is; we probably learned its molecular formula at secondary school. (2R,3S,4R,5R)-2,3,4,5,6-Pentahydroxyhexanal, on the other hand – its systematic name – is rather less familiar".

The point is clear here, but then the biologist joins the conversation, and I here them ask "do you mean the open or the closed form of glucose?", see this page. The open version in the longer, less familiar name has InChIKey GZCGUPFRVQAUEE-SLPGGIOYSA-N. Anyway, this is why I had started the "Woordenboek Organische Chemie" in 1993-1994, with a first appearance on the web in 1995. 

Day wonders: "Today, most chemists use a combination of ‘old’ and systematic names, everyone muddles along, and we might wonder if it even matters any more". This is a question that more people are wondering. Do systematic IUPAC matter that much still? Because we have better representations of the chemical structure: for line notation there is plenty, including SMILES and InChI and if we go to more than one line, there is MDL molfiles, CML, and a lot more there too.

And systematic names are not easy to come up with: it requires expensive software; manually creating them is not simple. In fact, today an experienced organic chemist (ChemBark) discovered his systematic naming for fairly simple compounds was 8 years outdated: "That molecule is properly named 4-ethenylheptane. This important news did not seem to travel to my friends or the people who publish organic chemistry textbooks. So, to my horror, I have been misleading hundreds of students for the past 7 years with antiquated rules".

So, please check his slides:

What I am asking for here is help. If anyone is teaching with the updated rules: do the following slides look correct? (slides 1-4 of 15) pic.twitter.com/KlgPuYEBkV

— ChemBark (@ChemBark) October 17, 2021