2-Chloro-5-pyridineboronic acid

2-Chloro-5-pyridyl boronic acid, an extremely important reagent in organic synthesis, is widely used in many fields.
First, in the field of medicinal chemistry, it can be used as a key intermediate. The construction of many drug molecules often depends on its participation. Due to its unique structure, it can be linked to other compounds through specific reactions to build molecular frameworks with specific pharmacological activities. For example, when developing new drugs targeting specific disease targets, 2-chloro-5-pyridyl boronic acid can be reacted with compounds containing specific functional groups to introduce a pyridyl boronic acid structure. This structure may have a positive impact on the binding force between the drug and the target, pharmacokinetic properties, etc., helping to develop drugs with better efficacy and fewer side effects.
Second, in the field of materials science, it also has important uses. It can be used to prepare functional materials, such as luminescent materials, conductive materials, etc. By reacting with other organic or inorganic compounds, it can be introduced into the material structure to give the material special optoelectronic properties. For example, when preparing organic electroluminescent materials, 2-chloro-5-pyridyl boronic acid participates in the specific structure formed by the reaction, or improves the luminous efficiency and stability of the material, which provides the possibility for the development of high-performance optoelectronic materials.
Third, in the field of organic synthetic chemistry, it is a commonly used synthetic building block. With its reactivity of chlorine atoms and boric acid groups, it can be coupled with different halogenated aromatics or olefins through various reactions, such as Suzuki-Miyaura coupling reaction, etc., to construct diverse organic molecular structures. The reaction conditions are mild and highly selective, which can effectively synthesize complex organic compounds, providing a powerful tool for organic synthesis chemists to assist in the synthesis of natural products and new organic functional molecules.

The synthesis method of 2-chloro-5-pyridyl boronic acid is always a delicate method. One method is to take 2-chloro-5-bromopyridine as the starting material, which is easy to obtain and stable. Anhydrous ether is used as the solvent, and at low temperature, it interacts with n-butyl lithium. N-butyl lithium is strong, and at this low temperature, it can capture the hydrogen of 2-chloro-5-bromopyridine and form an active organolithium intermediate. Then, quickly add trimethyl borate, the trimethyl borate meets the organic lithium intermediate, and the two are combined to obtain the lithium salt of trimethyl 2-chloro-5-pyridyl borate. After adding an appropriate amount of dilute acid, hydrolysis, the lithium salt becomes 2-chloro-5-pyridyl boric acid, and the purified product can be obtained by extraction, distillation, and recrystallization.
Another method is to use 2-chloro-5-aminopyridine as a base. It is co-prepared with sodium nitrite and hydrochloric acid to form a diazonium salt. The diazonium salt is very active. After mixing with sodium borohydride and zinc chloride, the two synergistically make the diazonium group easy to become a boron group to form 2-chloro-5-pyridyl boronic acid. After the purification step, the impurity is removed and the quality is improved to obtain the usable product.
Another method, using palladium as a catalyst, makes 2-chloro-5-halopyridine and diphenacol borate in a suitable solvent and adds alkali to coheat. Under the catalysis of palladium, the halogen atom of halogenated pyridine is transposed with the boron group of diphenacol borate to obtain 2-chloro-5-pyridinacol borate. This ester can be hydrolyzed to obtain 2-chloro-5-pyridinacol. Various methods have advantages and disadvantages, depending on the availability of raw materials, the high cost, and the simplicity of the steps.

2-Chloro-5-pyridyl boronic acid, its state is white to light yellow solid. This substance has certain solubility and can exhibit good solubility in common organic solvents such as dichloromethane, N, N-dimethylformamide, which is conducive to uniform dispersion in the organic synthesis reaction system and promotes the smooth occurrence of the reaction.
Its melting point range is specific, about 120-125 ° C. This melting point characteristic is of great significance in the purification and identification of compounds. By means of melting point determination, the purity of the substance can be determined. If the purity is high, the melting point should approach this range; if it contains impurities, the melting point may be offset.
From the perspective of chemical activity, the boron atom in 2-chloro-5-pyridyl boronic acid has electron-deficient properties, making it an electrophilic reagent that can react with many nucleophiles. In particular, it can undergo Suzuki-Miyaura coupling reaction with halogenated aromatics catalyzed by transition metals, which is a key means to construct carbon-carbon bonds and is widely used in drug synthesis, materials science and other fields. The chlorine atom is also reactive and can be replaced by nucleophiles to realize functional group transformation on the pyridine ring, providing various pathways for the structural modification of organic molecules. However, it is necessary to pay attention when storing and using, because it is more sensitive to humidity, contact with moisture or hydrolysis, resulting in reduced activity, so it usually needs to be properly stored in a dry environment, and the operation should be completed under anhydrous conditions as much as possible.

There is a question today, what is the price range of 2-chloro-5-pyridyl boronic acid in the market. This is a chemical substance, and its price varies due to many reasons. Looking at the example of "Tiangong Kaiwu" in the past, the price of various products often depends on the place of origin, supply and demand, and production methods.
Let's talk about the place of origin first. If it is produced here, near the water tower, its price is low; if it comes to a foreign country, it is transported around, and it is expensive and laborious, the price will be high. On supply and demand, if everyone wants it, more supply and less supply will be required, and the price will rise; if no one cares, the supply will exceed the demand, and the price will decline. The production method is also the main reason. If the production method is simple, the cost is low, and the price is low; if the production method is complicated and labor-intensive, the price will be high.
However, the price of 2-chloro-5-pyridyl boronic acid on the market is difficult to determine. According to the past market conditions of similar chemical materials, the price may be between a few yuan and a few tens of yuan per gram. However, this is only speculation, and the actual price should be subject to the current market conditions and merchant pricing. Market conditions are fickle, so you must visit the merchant in person and inquire about the price before you can get the real number.

2-Chloro-5-pyridyl boronic acid should be stored in a cool, dry and well-ventilated place. This product is more sensitive to humidity, and moisture is easy to cause it to deteriorate, so it needs to be strictly moisture-proof. It should be stored in a sealed container to prevent the intrusion of water vapor in the air. Temperature is also a key factor, and it should be kept in a low and stable state, generally not exceeding 25 ° C. Excessive temperature may cause chemical reactions and affect the quality. At the same time, it should be kept away from fire and heat sources, because of its active chemical nature, in case of open flame, hot topic or risk of combustion and explosion. The storage place should be separated from oxidants, acids and alkalis to avoid dangerous reactions caused by mixed storage. When handling, it must be handled lightly to prevent damage to the packaging and containers and expose them to undesirable environments. Such storage conditions can ensure the quality and stability of 2-chloro-5-pyridyl boronic acid during storage.