In organic compound names such as the one below what does the capital delta mean?
Example: 4-nitro-Δ4-isoxazolin-5-imine
This is a cut and past from a paper by Grundmann et al 1973 on nitrile oxides, Annalen der Chemie. In the original the "4" after the delta symbol was
superscript.Corrosive Joeseph - 24-1-2017 at 12:48
[Edited on 24-1-2017 by Corrosive Joeseph]Boffis - 24-1-2017 at 23:03
@CJ, thankyou very much. So basically the superscript number is the first carbon atom of the double bond counting from the O=1 and N=2 (since its an
isoxazole derivative). Hence the structure is impossible! It contains a 5+ valent carbon since the position of the 4-5 double bond is part of a ring
and the 5 position also has an imine (=NH) group attached. However take a look at the photocopies of parts of the pages from the paper. Note the
compound 13 on the 4th line of the introduction (this was where my original quote came from) and the compound 13 on the following diagram.
As far as I can see compound 13 in the second diagram should be 4-nitro-Delta2-isoxazolin-5-imine should it not? If I am wrong would someone please
explain why (I'm a mining engineer by training not a chemist so its not impossible that I'm wrong!). From what I understand the general rule in naming
heterocyclic is that they are numbered in the order the hetero atoms appear in the formula, so in an isoxazole the O=1 and therefore N=2; in an
oxazole O=1 and N=3 and so on. Praxichys - 26-1-2017 at 06:29
As far as I know there is only one isoxazoline. The "Δ" naming system seems to be clumsily (and incorrectly) used here.
IUPAC prefers 4,5-dihydroisoxazole to isoxazoline as the heterocycle section, but since there is an imine involved (and not an amine as the
paper suggests) you can specify where the single point of unsaturation lies with (H). I believe the correct name to be
4-nitroisoxazol-5(4H)-imine.
Although, it could be that I'm simply not familiar with the Δx system. I generally do not deal with it. I'm not a chemist by trade either!
EDIT: Also correct (but clumsier) would be 4-nitro-4hydroisoxazole-5-imine.
[Edited on 26-1-2017 by Praxichys]Boffis - 27-1-2017 at 10:32
Thank you Praxichys, when I read papers like this one in a highly regarded journal I tend to assume they are right and I am ignorant!BILLBUILDS - 27-2-2017 at 12:53
The delta symbol imply means "heat" or "energy input" it's put above reaction arrows the same way you would write which solvent and catalyst you are
during
The delta symbol imply means "heat" or "energy input" it's put above reaction arrows the same way you would write which solvent and catalyst you are
during
While that is true in the context that you describe, if you were to actually read the OP you'll see
that this is a completely unrelated context.
