Although it has already been explained here that the use of the "Δ" (Greek capital delta) character is not recommended to designate unsaturation in individual names, IUPAC 1989 Nomenclature of steroids states that it may be used, however, in generic terms, like "Δ5-steroids"; see note 3) on page 10. What are the current trends on whether should we continue or cease using the "Δ" symbol to describe a double bond per se (rather than in the name of a steroid) or just the position of such bond between consecutively numbered junctions, in various relevant compounds, not just steroids? Isn't it a concise and elegant way to denote such a bond, or is there a better, modern, suggested, clear way? Are there recommendations or best practices documents published on that, or research papers? For, example, instead of writing "steroids with a double bond between carbon 5 and 6 junctions" we could simply write "Δ5-steroids", an example given in the note 3) on page 10 of the UIPAC Nomenclature of steroids of 1989? Here is such an example in practice, in a 2020 publication (quote): "couple of Δ5-steroids with hydroxyl group at C3 position". Can we just use the "Δ" symbol to describe the position of the double bond e.g. "3βHSD isomerizes the double bond from the Δ5 to the Δ4 position" or just (quote): "Δ5 → Δ4 isomerization by 3βHSD"? Or should we cease the use of the double-bond position as a common denominator in favor of other similarities in a group of compounds, e.g. "3-keto-steroids" instead of "Δ4-steroids" or "3-hydroxy-steroids" instead of "Δ5-steroids"?

  • 1
    $\begingroup$ As you care of these things, "HSD3B2 isomerizes the double bond from the Δ5 to the Δ4 position"? does not tell anything clear. Moreover 5,6 to 4,3 position is also a common possibility (and doesn't require special character). $\endgroup$
    – Alchimista
    Nov 9 '20 at 8:01

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.