Nitration method for aryl phenol or aryl ether derivative

Abstract

The invention relates to a nitration method for an aryl phenol or aryl ether derivative. The method comprises the steps of stirring an aryl phenol or aryl ether compound, nitrate, trimethylchlorosilane (TMSCl) and a copper salt in an acetonitrile solution in air at room temperature, simultaneously, monitoring extent of reaction through a TLC dot plate, removing a solvent from a mixture by a rotaryevaporator after a substrate is consumed completely, and carrying out purification through a silica-gel column, thereby obtaining a nitroolefin derivative. Meanwhile, the selective mono-nitration orbis-nitration of the substrate can be achieved through controlling equivalent weight of the nitrate. Compared with the prior art, the nitration method disclosed by the invention has the advantages that the consumption of strong-acid substances is avoided, the reaction conditions are mild, the yield is high, the applicable range of the substrate is wide, reaction activity is free of obvious attenuation after an amplified reaction, and an excellent yield is still obtained, so that the method has an obvious industrial application value.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a nitration method for aryl phenol or aryl ether derivatives. Background technique [0002] Nitro-substituted aromatic compounds are a very important class of intermediates, which are widely used in the fields of medicine, pesticides, dyes, and explosives. The traditional nitration reaction uses concentrated sulfuric acid and nitric acid mixed acid as the nitration reagent. This method has mature technology and low cost, but the utilization rate of atoms is low, the environmental pollution is serious, and there are many by-products, the reaction is violent, and there is a huge potential safety hazard. [0003] In recent years, many chemists have been working on the optimization of the nitration reaction of aromatic hydrocarbons. In addition to using strong acidic substances such as nitric acid and concentrated sulfuric acid, trifluoromethanesulfonic acid or acetic anhydride as n...

AI Technical Summary

Problems solved by technology

The common nitration process involving transition metal catalysis is the most common C-H nitration strategy with Rh and Pd as catalysts, while transition metals such as Zr, Ce, Bi and Fe achieve the target substrate at high temperature through the corresponding nitrate of super chemical equivalent. Nitration (Xie, F.; Qi, Z.; Li, X.Angew.Chem., Int.Ed.2013,52,11862-11866.Fors,B.P.; Buchwald,S.L.J.Am.Chem.Soc.2009,131 , 12898-12899. Selvam, J.J.P.; Suresh, V.; Venkateswarlu, Y. Tetrahedron Lett. 2006, 47, 2507-2509. Wasinska, M.; Korczewska, A.; -150.), these methods either use expensive transition metal catalysis, or the substrate is severely restricted, and require aryl halides or other aromatic hydrocarbons with directing groups; and the reaction conditions require high temperatures (such as 130 ° C), which is potentially safe At the same time, most of these new methods are nitration reactions of free radical processes, and the reactions are uncontrollable when enlarged, with many by-products and a serious decline in yield, which also limits its industrial application

In 2019, Maruoka developed an electrophilic nitration of phenol using trivalent iodine as a catalyst at room temperature and using relatively expensive aluminum nitrate, but the corresponding nitrated products could only be obtained in a low yield (Kevin, A.J.O.; Maruoka, K.; Org. Lett. 2019, 21, 1315-1319.)

Although the method has relatively mild conditions and high product yield, its substrates are severely limited, and the acetyl nitrate needs to be prepared with fuming nitric acid, and the preparation process of the ionic functional liquid is cumbersome.

Chinese patent (CN108530242A) "A direct nitration method for electron-rich aromatics" uses tert-butyl nitrite to nitrate phenyl ethers at room temperature. The method has mild reaction conditions and does not require a catalyst, but the product yield is low

This method is simple to operate and the conditions are mild, but it uses sodium nitrite and hydrogen peroxide system. When scaled up, the mixture of peroxide and nitration products has the risk of explosion, and the atom economy is low, which does not conform to the concept of green chemistry.

Chinese patent (CN107033005A) "A Nitrification Method for Aromatic Compounds" improves the production process and uses a high-gravity reactor to avoid side reactions caused by excessive local concentrations and improves nitrification efficiency. However, it still uses a mixed acid system. The equipment is corrosive and the reaction temperature is high

[0005] To sum up, in the existing nitration technology solutions, the classic mixed acid nitration system has safety risks, and the reaction is violent and uncontrollable; the newly developed C-H nitration technology requires guiding groups and noble metal catalysis, and its amplification reaction has many by-products ; and the direct nitrification of substrates by transition metal nitrates generally requires a high temperature environment, and most transition metal nitrates are relatively expensive (Zr(NO 3 ) 4 , Bi(NO 3 ) 3 etc.), which is not conducive to actual production, and the nitration process developed by Maruoka has disadvantages such as high raw material cost and low yield

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