Sciencemadness Discussion Board

regioselective red. electrophilic 6-demethoxylation of ß-naphthalene derivate

karlos³ - 21-2-2022 at 22:31

Ok so I have this compound, its a ketone actually(a beta-propionaphthone), and in case I would want to remove the 6-methoxy group, and given its very similar characteristics thanks to its position to the 4-methoxyphenyl group, what speaks against the attached procedure working analogous for this analogue?
It seems logical to me, but I probably miss something.

The paper is one of the Azzena et al papers, where they react 3,4,5-trimethoxybenzaldehyde (and trimethoxyphenylalkyl ketones, in follow up papers), as their acetals with metallic sodium in THF, then react that with an electrophile, which can also be water, and thus resulting in cleavage of the 4-methoxy group.

I know I could remove that group else, but it would be more work and thus easier to simply acylate naphthalene without the methoxyether from the start on.
If this could work that simple, it would at least warrant the one or other experiment.

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RustyShackleford - 22-2-2022 at 10:06

What exactly is the compound you have? you say you have a beta-propionaphthon (presumably the first beta, pos 2), but then a methoxy you want to remove on 6. Isnt that then quite unlike the 4-methoxy benzaldehyde? or are you thinking the resonance will allow it to behave the same? worth a shot IMO.

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clearly_not_atara - 22-2-2022 at 19:31

In principle, yes, although the resonance will be weaker with naphthalene because the whole naphthalene is involved. So not sure if it will work.

But I thought the binding data said the 6-methoxy was fine?


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karlos³ - 23-2-2022 at 22:54

Quote: Originally posted by clearly_not_atara  
In principle, yes, although the resonance will be weaker with naphthalene because the whole naphthalene is involved. So not sure if it will work.

Oh, that is interesting via enolate!
Guess I will try that too :)
Quote: Originally posted by clearly_not_atara  

But I thought the binding data said the 6-methoxy was fine?

Binding data for exactly those will be had in a while, not yet though :)
The chinese had a few and hard to dig up, but of the weaker analogues.

First bioassays were not strongly convincing, but nothing was tried in depth yet, and then again, only a little bit of the pyrrolidine and the dimethylamine, and there is so much more to do.

I just have a whole lot of this stuff and I am considering all options to try out with it :)
I've even coupled this already via bromoketone with 1-benzylpiperazine, (apparently a precursor for a class of triple reuptake inhibitor antidepressants... not with the carbonyl, who knows :o)