# How is 4H‐1,4‐oxazocine aromatic?

I’ve found 4H‐1,4‐oxazocine in my chemistry book and I’m perplex as it states as aromatic:

I can count 6 electrons on p orbitals which could satisfy Hückel’s $$n = 1,$$ but the oxygen is sp3-hybridized. Even if we’d consider one lone pair as one sp2-bonding, the second lone pair would add 2 electrons to the p system, counting a total of 8 electrons, which doesn’t satisfy Hückel’s rule.

• So what about the nitrogen lone pair? – Waylander Jan 13 at 17:41
• @Waylander so basically I could count n=10 considering O as $sp^2$ with a lone pair on the pi system? – Pseuronimo Stilton Jan 13 at 17:44
• Didn't we do the same in furan? Didn't we do the same in pyrrole? Well, now put the two together. – Ivan Neretin Jan 13 at 18:04
• @IvanNeretin Thanks! I actually had this preconception I’ve read somewhere that n=number of aromatic rings, thus in my reasoning this compound couldn’t have more than 6 e^- in its pi system. – Pseuronimo Stilton Jan 13 at 18:13
• @pseuronimo n is not the number of aromatic rings, nor could it be since the 4n+2 rule is really accurate only for a single ring. Rather it's an optimal value that depends on ring size. Typically n=0 for a three-atom ring, 1 for 4-7 atoms, 2 for 8-9 atoms. Aromaticity is usually insignificant for larger rings than that. – Oscar Lanzi Jan 13 at 19:49