[heyhey]

considering that a molecule of interest has both aliphatic amines and aromatic amines, how would you go about making a carbamate linkage via couplIng the aliphatic amine to a carboxylic acid??? Without reacting the aromatic amine?

I was thinking about edc but that does not give as pure of a product especially when it is in excess. Another option is using methylmorpholine and cdmt but my concern is with the hazards associated with working with the mmp. CDI is another possibility however it cannot be used in aqueous solution which I prefer to have the reaction take place in...

[wildfyr]

What purification methods can you use? A column can probably separate the aliphatic vs aromatic product of the EDC/NHS coupling.

[rolnor]

Do you really mean carbamate, or is it amide? I think you need a not so reactive acylating agent to maximize the selectivity for the aliphatic amino-group, perhaps an acylazide? A more complicated way would be to diazotize the aromatic aminogroup with nitrite at a pH that completely protonate the aliphatic amine but not the aromatic one, I have used TFA as acid. Then you add sodium azide so you get the aromatic azide. You can then acylate the aliphatic aminogroup and reduce the azide with Ph3P. This is a longer route but the steps give good yield in many cases.

[wildfyr]

that diazotization sounds tough. It may react with the electron rich un-diazotized benzene rings and give you an awful dye tar. Even if you can avoid that its a tough pH balance.

[rolnor]

I have done it successfully, but it was never published, many years ago. If it is a good way in this case depends on how the rest of the molecule looks.

[clarkstill]

Are you able to show us the structure heyhey?

[clarkstill]

Are you able to show us the structure heyhey?

I think 'heyhey' was an autocorrect fail... oops