​Most peptide synthesis is achieved by solid-phase peptide synthesis using Fmoc or Boc protection methods, however when Fmoc-OSu is used, due to the formation of dipeptide (or tripeptide) and β-alaninamide impurities, in Introduction of an unprotected N in an amino acid into the Fmoc appears to be challenging. Here we introduce an efficient method for the synthesis of Fmoc-Gly-OH based on the oxime derivative Fmoc-Amox without any side reactions.

The amide bond is not only an important structural functional group of natural active compounds, such as various polypeptides and proteins, but also an important component of many organic compounds, especially pharmaceuticals. According to statistics, the proportion of drugs containing amide bonds is as high as 25%, so the synthesis of amide bonds is particularly important. There are related articles on the synthesis of amide bonds in the official account of Haofan Biology, and each detailed synthesis method will not be repeated here. There are many ways to synthesize amide bonds, but the most basic and direct method is to form amide bonds through dehydration of amino and carboxyl groups.

​2-Chloro-1-methylpyridinium iodide, referred to as CMPI, is a commonly used condensation reagent. Its English name is 2-Chloro-1-methylpyridinium Iodide, and its molecular formula is C6H7ClIN. The CAS number is 14338-32-0. It is a light yellow solid at room temperature. It is usually used in dichloromethane, tetrahydrofuran and acetonitrile. It is very stable at room temperature and stored in a cool and dry place.

4-(tert-butyldimethylsilyl)oxo-1-butanol is a colorless to light yellow oily substance with a CAS number of 87184-99-4. The compound is obtained by single-protecting 1,4-butanediol with TBS, and TBS is used as a hydroxyl protecting group and is stable under alkaline conditions. With this characteristic, 4-(tert-butyldimethylsilyl)oxo-1-butanol can modify the other terminal hydroxyl group under alkaline conditions. The dehydrogenation of the hydroxyl group of 4-(tert-butyldimethylsilyl)-1-butanol to form aldehyde can be used as an intermediate in the synthesis of anticoagulant beraprost sodium tablets, and the oxidation to acid can be used in the synthesis The Napabucasin derivatives can also be directly used in the synthesis of ROCK kinase inhibitors and indoleamine 2,3-dioxygenase (IDO) enzyme activity regulators.

There are many ways to synthesize amides, and the method of first activating carboxylic acids is more common, such as first making acid chlorides, acyl imidazoles, acid anhydrides or activated esters, etc., and then reacting with amino compounds to form amides. As a condensing agent, triphenylphosphine can also activate carboxylic acid. Here are several ways to combine it with triphenylphosphine.