I have a molecule with 5 secondary amine as a functional group and I need to do a reaction on one of them. How can I protect the other 4 secondary amine groups?
I'm not sure it's the best way. But you can use 2-4 equivalent of Boc reagent and separate the products. Then do NMR and select the 4 protected amine. I don't know how to selectively protect 4 amine.