I need some papers which help me to understand the selectivity of amidification and amination reaction, in case of the presence of carboxylic group, ketone function and lactone ring as shown in the attached image. How can I address this reaction to form amide group avoiding the reaction with ketone or lactone ring?
You should increase the reactivity of carboxyl by :conversion of the carboxyl to acyl chloride, then reacting with amine. You may need to protect the hydroxyl groups before doing such process.
Activate the carboxylic with converting it to acyl-chloride will increase its activity.... Have you tried boronic acid as catalyst ??
Another method is to try converting carboxylic acid function directly to the amide by reacting it directly with cyanuric flouride followed by the amine. Or one can use TFFH as the fluorinating agent. TFFH is a nonhygroscopic air stable salt, that can be handled under routine conditions,6 and is available commercially.
Do not convert to the acid chloride as that would be incompatible with your secondary alcohols. Dicyclohexylcarbodiimide in acetonitrile should offer you good selectivity under neutral conditions with a relatively simple work up. Add the amine to a cold solution of the diimide and the carboxylic acid. Dicyclohexylurea will precipitate out of the reaction as it proceeds.
You could use acylbenzotriazoles as proposed by Katritzky :J. Org. Chem. 2000, 65, 8210-8213
It would seem that converting the acid to the imidazolide with carbonyldimidazole then reacting that with 1 eq. of your amine would be a viable choice. The reactivity of the lactone is of concern may not be an issue if the amount of amine is controlled. The main problems with DCC are twofold: removal of DCU and dermal sensitivity. PyBOP is a good coupling reagent but may be too expensive and there could be workup issues. Making and acyl chloride or fluoride leads to other issues with the secondary hydroxyls and the lactone as has been pointed out. As you have probably discovered amide formation seems straightforward but the correct method may not be obvious. Good luck.
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