4-(Dimethylamino)pyridine, ReagentPlus

4- (dimethylamino) pyridine, ReagentPlus (a reagent specification) Common uses are as follows.
In the field of organic synthesis, this reagent is often used as a high-efficiency nucleophilic catalyst. It can accelerate the esterification reaction. For example, in the preparation of carboxylic acid esters, the reaction may take a long time and a high temperature under conventional conditions, and then the addition of 4- (dimethylamino) pyridine can make the reaction proceed rapidly under milder conditions. Due to its lone pair electrons on the nitrogen atom, it has strong nucleophilicity to acyl groups. It first binds to the acyl group to form an active intermediate, and then the alcohol attacks the intermediate, thereby promoting the formation of esters.
In the amidation reaction, it also plays an important role. It can increase the reaction rate and yield, and promote the efficient conversion of carboxylic acids and amines to amides.
In addition, in some reactions involving nucleophilic substitution, 4- (dimethylamino) pyridine can activate the substrate, making the substitution process more prone to occur. For example, the reaction between halogenated hydrocarbons and nucleophiles can optimize the reaction path and reduce the activation energy of the reaction.
In many reactions in organic synthesis, with its unique structure and catalytic activity, it can effectively improve the reaction efficiency, provide convenience for the synthesis of organic compounds with specific structures, and help chemists build complex organic molecular structures more efficiently.

4 - (dimethylamino) pyridine, ReagentPlus, is a commonly used catalyst in organic synthesis. Its physical properties are unique and worth studying.
This substance is in the state of white to light yellow crystalline powder at room temperature, and it is delicate in appearance, like fine jade dust. Its melting point is about 112-114 ° C, just like winter ice, it melts when it is warm, and the temperature reaches 211 ° C, and at higher temperatures, it turns into gaseous ascension.
4 - (dimethylamino) pyridine has good solubility. It can be dissolved in common organic solvents, such as ethanol, chloroform, dichloromethane, etc., just like fish entering water and blending freely. In ethanol, it can be uniformly dispersed to form a clear solution. This property makes it well mixed with many reactants in an organic reaction system to promote the progress of the reaction.
And it has a certain degree of hygroscopicity. If exposed to air, such as a sponge absorbs water, it gradually absorbs water vapor, so it needs to be properly sealed to prevent deterioration when stored. Its density is about 1.129 g/cm ³, which is slightly thicker than common liquids. It is placed in a container and is stable and safe. Due to the nitrogen atoms in its molecular structure, it is alkaline to a certain extent. It can play a unique catalytic role in organic synthesis reactions, participate in many reaction processes, and affect the rate and direction of reactions. It is an indispensable and important substance in the field of organic chemistry.

When storing 4 - (Dimethylamino) pyridine (ReagentPlus), there are many things to pay attention to. This is a catalyst commonly used in organic synthesis, and its properties are quite lively.
First, pay attention to the storage environment. It should be placed in a cool and dry place, away from direct sunlight. Due to light and high temperature or deterioration, its catalytic activity is affected. If exposed to strong light and high temperature, the molecular structure may be damaged, and then the catalytic function will be lost.
Second, to ensure that the storage is well sealed. This substance is easy to react with moisture and oxygen in the air. Once damp, or form impurities, change its chemical properties. Contact with oxygen, or cause oxidation reaction, so that the quality is reduced. Therefore, the storage container must be tightly sealed, and a glass bottle can be used with a rubber plug or a plastic cover to prevent the intrusion of air and water.
Third, it should be placed separately from other chemicals during storage. Because of its certain chemical activity, if it is co-stored with some oxidizing and reducing substances, or cause dangerous chemical reactions, such as fire, explosion, etc.
Fourth, the storage site needs to be well ventilated. If it evaporates in a limited space, the concentration will accumulate too high, or it will pose a hazard to human health, and it will also increase safety risks such as fire. Good ventilation can disperse the volatile gas in time and maintain the safety of the environment. In this way, Fangdeshan stores 4- (dimethylamino) pyridine to maintain its quality and properties.

The chemical stability of 4- (dimethylamino) pyridine, ReagentPlus is related to its performance in various chemical situations. This substance has certain stability under normal conditions. In its structure, the pyridine ring is connected to the dimethylamino group, and the conjugate system of the pyridine ring gives it certain stability, and the dimethylamino group also affects the overall stability.
In the environment of normal temperature and pressure, if there is no specific reaction with the reactant, 4- (dimethylamino) pyridine can maintain a relatively stable state, and it is not easy to decompose and polymerize by itself. However, when encountering strong oxidants, due to the nitrogen-containing elements in the structure, the stability may be damaged due to oxidation. For example, when it encounters a strong oxidizing agent such as potassium permanganate, the pyridine ring or amino group may undergo an oxidation reaction, causing its structure to change.
If it is in a high temperature environment, it may also affect its stability. High temperature may cause intra-molecular energy changes, causing chemical bond vibrations to intensify. When the energy reaches a certain level, it may cause bond breakage, which in turn changes the material structure.
When encountering acidic substances, the nitrogen atom in 4- (dimethylamino) pyridine is basic due to its lone pair electrons, and will react with the acid to form corresponding salts. This process also changes its original structure and stability.
Overall, 4- (dimethylamino) pyridine is relatively stable under conventional conditions, but its stability may be affected by special conditions such as specific chemicals and high temperatures.

There are several common methods for preparing 4- (Dimethylamino) pyridine (ReagentPlus).
First, pyridine is used as the initial material. Pyridine is first reacted with formaldehyde and dimethylamine through Mannich. In an appropriate reaction vessel, mix pyridine, formaldehyde solution and dimethylamine aqueous solution in a certain ratio, add an appropriate amount of acid catalyst, such as hydrochloric acid, at a suitable temperature, usually 40-60 ° C, and continue to stir for the number of reactions. After the reaction, adjust the pH value of the reaction solution to alkalinity with alkali solution, and then purify the product by extraction, distillation and other means. The extractant used can be an organic solvent such as dichloromethane, which is separated by the difference in solubility of the product in different solvents. Distillation can further remove impurities to obtain high-purity 4- (dimethylamino) pyridine.
Second, it is obtained by reacting 4-halopyridine with dimethylamine. Take 4-halopyridine (such as 4-chloropyridine or 4-bromopyridine) and place it in the reaction system, add dimethylamine alcohol solution or dimethylamine gas, and add an appropriate amount of acid binding agent, such as potassium carbonate, to neutralize the hydrogen halide generated by the reaction. The reaction temperature depends on the activity of halopyridine, 4-chloropyridine reaction temperature is slightly higher, about 80-120 ℃; 4-bromopyridine activity is higher, the reaction temperature may be reduced to 60-100 ℃. During the reaction, the reaction process is closely monitored, and the thin layer chromatography (TLC) method can be used. After the reaction is completed, the solid acid binding agent product is filtered off, the filtrate is distilled under reduced pressure to remove the solvent, and the residue is separated by column chromatography. Silica gel is used as the stationary phase, and a suitable proportion of petroleum ether and ethyl acetate mixture is used as the mobile phase to obtain pure 4- (dimethylamino) pyridine.
Third, 4-pyridinone is used as the raw material. 4-Pyridinone is first reacted with phosphorus oxychloride to convert the hydroxyl group into a chlorine atom to form 4-chloropyridine. This reaction requires an anhydrous environment, low temperature such as 0-5 ° C, slowly adding phosphorus oxychloride, and then warming to 50-70 ° C. After that, 4-chloropyridine is reacted with dimethylamine according to the above method of reacting with dimethylamine, reacting with dimethylamine and acid binding agent, followed by filtration, distillation, column chromatographic separation, etc., and finally 4- (dimethylamino) pyridine is obtained.