chlordiazepoxide N-O bond

[wungchow]

Anyone wanna explain the significance of that funky N-O bond ? I've rarely, if ever, seen it in other pharmaceutical compounds. Could be an interesting substitution to make on various phenethylamine compounds.

 

[Beenhead]

Nitrogen generally makes three bonds. This one seems to have four. There must be a partially positive charge because of the extra bond. It looks like, though, that the electron in question must spend a little more time with the oxygen because of the partial negative charge with it. Not positive though, but that is what it looks like.

 

[bigmac74]

Nitrogen generally makes three bonds. This one seems to have four. There must be a partially positive charge because of the extra bond. It looks like, though, that the electron in question must spend a little more time with the oxygen because of the partial negative charge with it. Not positive though, but that is what it looks like.

The + by the nitrogen is indicating one less electron than normal, and the - by the oxygen is indicating one more electron than normal, it's nothing to do with partial charges (or am I just reading your post wrong)?

Anyway, I've never seen this in pharmaceuticals before either, I assume it's metabolized into something active?

 

[DadeMurphy]

This structure is known as a ylide. The nitrogen with 4 bonds to it is known as a quaternary amine. The neighbouring / opposite charges are just one way of representing the charge distribution which is actually a wierd hybrid of orbitals...in reality quite different than this resonance form but I'm not that well versed in MO theory.

 

[vecktor]

these are N-oxides (aka Amine oxide). quite commonly found as p450 oxidative metabolites of nitrogen heterocycles and some tertiary amines.
they are not a potential modification to phenethylamines as the theoretical primary amine N-oxide tautomerises to the N-hydroxylamine.

the positive-negative charge drawing of their structure is convenient but isn't a true representation, representing the structure with an arrow from the nitrogen to the oxygen is more correct. The structure of amine oxides was one of the great challenges for chemistry at the turn of the century through to the 1930's, Fritz Haber did a lot of work on them.

the N-oxides of some opiates are active.

 

[Helios.]

See also Rogaine.
N-oxide-pyridinial nicotine.

 

[haribo1]

It's a prodrug. The N-methyl on the amine is lost and the amine becomes a ketone or, rather, an amide is formed. The N->O is lost so you end up with nor-diazrpam.