Question

What is the skeletal structure for `C_6H_11NO`?

Answer 1

It is not particularly obvious, but it probably looks like this:

https://en.wikipedia.org/wiki/Caprolactam

You can tell that a lactam is essentially a cyclic amide.

• "Lact" refers to a cyclic ester.
• "am" is an add-on that implies an am-ide instead of an ester.
• "Capro" means that there were six carbons in the compound before the ring formed, starting from the carbonyl carbon and ending at right before the nitrogen.

(`epsilon`-caprolactam has CAS: 105-60-2, by the way, so you can google that too.)

Another possibility could have been hexanenitrile oxide (CAS: 88911-37-9), but that is not very likely. I did find that on https://scifinder.cas.org/, however, it seems theoretically generated, and it of course looks impossible due to nitrogen breaking the octet rule. (Which brings me to wonder why it was even in the database.)

Perhaps the compound could work if it was a `"C"-=stackrel(+)("N")-"O"^(-)` connection, but it's not proven to exist as far as I can tell.