[chloec]

Hi,

I have the compound meridianin A and need to retrosynthesise and then have 2 different forward synthesis for it. My lecturer informs me there is suzuki coupling between the indole and the pyrimidine however I am struggling to do it as we have to form meridianin A from readily available precursors and the "indole-3-boronic acid" I would require based on my research in to the suzuki coupling isn't actually available and I'm not sure how I would make it.

I hope someone can offer me some guidance on how to approach this problem, thanks!

[Archer]

Have to tried anything on this?

I have had some interesting times with indole, it can behave like an aromatic compound in some reactions but often the N-H creates issues as this is slightly acidic (pKa 21).

You may be able form the dimethylborate of indole by first reacting indole with Et-MgBr to form


When this acts as a nucleophile it does so at the 3-position (at least in alkylation and acylation reactions)

You should be able to react this with trimethylborate to form the dimethylboronic ester. Acid hydrolysis should yeild the desired boronic acid.


I don't know if this will work but this is the best I can offer. (For some reason the SMILES has aromatised the indole and omitted the proton from the nitrogen but I hope you get the general idea)

[sjb]

You should be able to react this with trimethylborate to form the dimethylboronic ester. Acid hydrolysis should yeild the desired boronic acid.

Do you need to hydrolyse the ester? I've had some sucess with pinacolboronic esters in the past.

I don't know if this will work but this is the best I can offer. (For some reason the SMILES has aromatised the indole and omitted the proton from the nitrogen but I hope you get the general idea)

I think that's because you used [ smiles]OB(O)c2cnc1ccccc12[/smiles]. [ smiles]OB(O)C2=Cnc1C=CC=C12[/smiles] works as  intended, even if you do have the benzene ring delocalised (don't have access to a molecular drawing package to sort that out at the moment) -see

[Archer]

Do you need to hydrolyse the ester? I've had some sucess with pinacolboronic esters in the past.

I have never conducted a Suzuki coupling reaction so I was not aware that you could use esters. Usefull to know, thanks.

Thanks for the tip on the SMILES too, I shall use that for next time I am trying to draw an indole nucleus.