Heterocyclic compounds play an important role in biological processes, and the main part of organic compounds isolated from nature is composed of nitrogen heterocycles. A large number of data reports have shown that heterocyclic compounds as analgesic, anti-inflammatory and anti-migraine drugs can effectively regulate nitric oxide stress and target free nitrogen and oxygen free radicals, which is a promising strategy for future pain treatment.

Boc group protection is widely used in organic synthesis, and it is also an amino protecting group widely used in peptide synthesis. Especially in solid phase synthesis, Boc group is often used for amino protection. The removal of the Boc group has the following advantages: it is easy to remove by acidolysis, but it has certain stability; what is produced during acidolysis is tert-butyl cation and then decomposes into isobutene, which generally does not bring side reactions; , hydrazinolysis, and many nucleophiles; stable to catalytic hydrogenolysis, but much more sensitive to acids than Cbz. Therefore, the removal of the Boc group is mainly based on acid hydrolysis, but acid-sensitive substrates can also be removed under neutral or alkaline conditions.

Burgess reagent (Burgess reagent), that is, methyl N-(triethylsulfamoyl) carbamate, is a kind of internal salt of carbamate, the chemical formula is C8H18N2O4S, the structural formula is shown in the figure, and the molecular weight is 238.3. Appearance is off-white powdery solid. This product is very sensitive to air and humidity, and is easy to oxidize. It should be stored in nitrogen at low temperature and used as soon as possible. In organic synthesis, it is soluble in most organic solvents and is an efficient dehydrating agent.

At the end of 2021, Pfizer's new crown oral drug Paxlovid was approved by the US FDA for marketing, which aroused widespread concern. One of the main ingredients of Paxlovid is the 3CL protease inhibitor code-named PF-07321332. PF-07321332 plays an important role in the life cycle of a variety of coronaviruses, and its potential advantage is that it can work on all current variants of the new coronavirus. Therefore, this small molecule drug has attracted strong interest from many pharmaceutical manufacturers.

Solid phosgene, also known as triphosgene. The chemical name is bis (trichloromethyl) carbonate [Bis (trichloromenthyl) Carbonate], abbreviated as BTC (structural formula shown in Figure 1) is an ideal substitute for phosgene. Phosgene and diphosgene are widely used in the synthesis of medicines, pesticides, organic intermediates, and polymer materials. However, due to their low safety, their usability is greatly limited. Phosgene and diphosgene have a low boiling point, are volatile and highly toxic, and have been banned or restricted in many countries.