Chemical reactions and stability of NHS ester

Hello!I want to ask, how can I put NHS on the hydroxy? Is there any related literature to recommend reading?Thank you

The carboxylic acid after NHS reacts with the hydroxyl group?Intersection

NHS esters and amino hydroxyl groups can react under alkaline pH conditions. This is undoubted. In contrast, the response rate is faster than the amino group.In response to your situation, it is difficult to avoid the reaction with a small amount of hydroxyl group. If it has a little effect on the nature of your materials, it doesn't matter, otherwise, it is recommended that you redesign the material synthesis experimental scheme.

You can find a way to protect the carboxyl group. After the amino group and the NHS-R react, it can be protected, but it can be imagined that many products will definitely lose.

Pay attention to the pH of the reaction is the key. The hydroxyl group will not easily react with the carboxylic acid ester