Butanedione example from pg. 61

[Aimiel Casillan 1J]

From the bottom of pg. 61 of the Intro to Organic Chem textbook, it lists the following line structure for butanedione:

As I was practicing to name this compound, I understood the use of -dione as a suffix since there are two ketones in this molecule. However, I initially wrote butane-2,3-dione to show where the ketones are placed, but why does the book simplify the molecule to just butanedione? Is it still correct for me to write butane-2,3-dione?

[Krish Seth 2L]

Using -2,3-dione is unnecessary, because the only way butandione can exit is if the oxygens are double bonded to the 2nd and 3rd carbon atoms. if the oxygen was attached to the 1st or 4th carbons, they would be aldehydes, not ketones. Also, the oxygens can't be double bonded to the same carbon atom, because carbon can only form 4 bonds.

[Jonathan Zuo 2J]

Remember that a ketone group is a R-(C=O)-R. That is, a ketone is a carbonyl thats carbon is also attached to two other side chains R. So in the case of a butane molecule, the only positions the ketones can be in are the 2 and 3 position. If a ketone is placed at the terminal end of the chain, it would be an aldehyde rather than a ketone. Because the ketones can only be attached to the 2nd and 3rd carbon, the numbering is not required.

But what you did isn't wrong and it doesn't hurt to be extra specific.