1, amino protection group, mainly includes the following categories: amide protection method: Because acylating reagents are easily available and cheap, it is very simple to convert amines into substituted amides. A very extensive amino protection method, monoacyl, is often enough to protect the amino group of primary amines and remains unchanged in oxidation and alkylation reactions. Amides are easily prepared from amines and acid chlorides or anhydrides and are relatively stable. Traditionally, they are heated in a strong acid or alkali solution.

2. Carbamate protection law: Carbamate substances, their substituted derivatives and other types of carbamates can be used as protective groups of amino groups and widely used in synthetic reactions, especially peptide synthesis. In peptide synthesis, carbamates are used as protective groups, so racemization is suppressed to a minimum. Among them, tert-butoxyformyl (Boc) is inert to catalytic hydrogenolysis and stable to alkali and nucleophile, which makes benzyl ester and carbamate of tert-butoxyformyl become ideal protective reagents in peptide synthesis.

3. Sulfonamide protection method: Sulfonyl-protected sulfonamide is the most stable nitrogen protection group with good crystal form, and its sensitivity to nucleophiles is much worse than that of more commonly used formamide protection groups. The difficulty of deprotection depends on the structure of amine. Sulfonamide derivatives with weakly basic amines (such as indole, pyrrole and imidazole) can be removed by simple alkaline water.