In the case of the reaction below, I would like a final product with ring-opened form of the spirolactam (for fluorescence-ON) but with another moiety being attached to the NH2 (via nucleophilic addition with ketones/aldehydes/2-chloropyridine for instance). However, which one should comes first? The ring opening via acidification or nucleophilic addition.
I am not an expert at all, but it seems to me that the more basic terminal amine would be protonated in acid, that would inhibit its nucleophilicity. So, you need to do the addition first.
I would suggest to do derivatization of amine first, then proceed with acid-catalyzed hydrolysis - unless the product of amine derivatization is acid-sensitive (or, if the derivatization procedure is incompatible with your lactam ring).
However, it is only a general recommendation, the situation may change depending on the structure of the desired final compound (i.e., what exactly you want to attach to amine).
Mike Kondrasho , Vladimir Khlebnikov , Kavita Rawat
, thank you so much for the answers. Much appreciated. If benzaldehyde is to react with the amine, I think the derivatization of amine should come first as suggested by Vladimir and Mike or the nucleophilicity will be hampered.