4-nitropyridine N-oxide

4-Aminopyridine and its N-oxide are widely used. 4-Aminopyridine is a key intermediate in the field of organic synthesis. It can be used in the synthesis of drugs to prepare many drugs with special curative effects. Due to its unique chemical structure, it can participate in a variety of chemical reactions and build complex drug molecular structures, opening up a broad path for pharmaceutical research and development.
Furthermore, in the field of materials science, 4-Aminopyridine can be used as a synthetic raw material for functional materials. With its reaction properties with other substances, materials with special electrical, optical or mechanical properties can be prepared, which have potential applications in electronic devices, optical instruments and other fields.
As for the N-oxide of 4-aminopyridine, it has shown extraordinary utility in the field of catalysis. It can be used as a high-efficiency catalyst or catalyst ligand, which can significantly improve the reaction rate and selectivity in many chemical reactions. In organic synthesis, the booster reaction proceeds efficiently in the expected direction, reducing the occurrence of side reactions and improving the purity and yield of the product.
And the unique electronic structure of N-oxide makes it exhibit catalytic activity that is completely different from the parent compound under certain specific reaction conditions, providing more possibilities for the optimization and innovation of catalytic reactions. In addition, in the field of agriculture, 4-aminopyridine and its N-oxides can be rationally modified and formulated, or can be used to prepare new pesticides, which may have positive effects on pest control, plant growth regulation, etc., to meet the needs of sustainable agricultural development.

4-Aminopyridine and its N-oxide, both of which have unique physical properties and are of great significance in many fields.
4-Aminopyridine, white to pale yellow crystalline powder at room temperature. Its melting point is between 158 and 162 ° C. This characteristic enables 4-Aminopyridine to realize the transformation of solid-liquid state in a specific temperature environment, providing a temperature basis for related process operations. The boiling point is about 277 ° C. When the temperature reaches this value, 4-Aminopyridine will be converted from liquid to gaseous state. Its density is about 1.172 g/cm ³, indicating the mass contained in 4-Aminopyridine per unit volume. This parameter is of great significance for material measurement, mixing and other operations. 4-Aminopyridine is slightly soluble in cold water, but easily soluble in hot water and ethanol and other organic solvents. This difference in solubility can be exploited when separating, purifying and preparing related solutions. Effective separation and dissolution of 4-aminopyridine can be achieved by means of different solvents and temperature conditions.
The N-oxide of 4-aminopyridine is also often white to light yellow crystalline powder in appearance. The melting point is about 167-171 ° C, which is similar to but different from that of 4-aminopyridine. This difference can be used to distinguish the two and separate mixed systems. Compared with 4-aminopyridine, 4-aminopyridine N-oxide has improved solubility in water, which is attributed to the change in the structure of N-oxide, which changes its interaction with water molecules, which makes it more advantageous in some aqueous system applications. At the same time, 4-aminopyridine N-oxide has enhanced thermal stability than 4-aminopyridine, and can maintain its own structure and property stability at higher temperatures, which shows unique application value in processes involving high temperature treatment steps.
The differences and characteristics of these two physical properties lay the foundation for applications in chemical synthesis, drug development, materials science, and many other fields. Scientists and producers can skillfully use their physical properties according to actual needs to achieve desired goals.

4-Aminopyridine and its N-oxides are very important compounds in the field of chemistry, each with unique chemical properties.
4-Aminopyridine, its intracellular amino group interacts with the pyridine ring, giving this compound significant alkalinity. Because the nitrogen atom in the amino group contains lone pair electrons, it is easy to combine with protons, and can form corresponding salts in an acidic environment. For example, when interacted with hydrochloric acid, 4-aminopyridine hydrochloride will be formed. This basic property makes 4-aminopyridine often used as a base in organic synthesis, participating in catalyzing many chemical reactions. At the same time, amino groups are also nucleophilic groups and can participate in nucleophilic substitution reactions. When it encounters a halogenated hydrocarbon, the nitrogen atom in the amino group will attack the carbon atom of the halogenated hydrocarbon, and the halogen atom will leave, thus forming a new carbon-nitrogen bond and realizing the construction of pyridine derivatives.
And 4-aminopyridine N-oxide, because the nitrogen atom connects to the oxygen atom, the electron cloud distribution changes, the electron cloud density of the pyridine ring decreases, and the stability is improved. Compared with 4-aminopyridine, its basicity is weakened. However, the oxygen atom of the N-oxide can be used as a nucleophilic check point to participate in nucleophilic reactions. Under certain conditions, it can react with electrophilic reagents and introduce various substituents on the pyridine ring. Moreover, it can also participate in oxidation reactions, and oxygen atoms may be further oxidized to form derivatives containing nitrogen oxides with more complex structures. In addition, 4-aminopyridine N-oxide has potential application value in the field of medicinal chemistry. Its unique electronic structure and spatial configuration may interact with specific targets in organisms, showing specific biological activities.

To prepare 4-pyridyl N-oxide, there are three methods.
First, oxidize it with peroxide. Take an appropriate amount of pyridine derivatives and dissolve them in suitable organic solvents, such as dichloromethane and chloroform. Then, slowly add peroxides, such as m-chloroperoxybenzoic acid (m-CPBA), which is a commonly used oxidizing agent. During the reaction, the temperature should be controlled in a moderate range, generally at a low temperature, between about 0 ° C and room temperature. Due to the high activity of peroxides and high temperature, it is easy to cause side reactions to breed. The reaction process can be monitored by thin-layer chromatography (TLC). When the raw material point disappears, the reaction is completed. After that, regular post-treatment, such as extraction, washing, drying, column chromatography separation, etc., can obtain pure 4-pyridyl N-oxide. The advantage of this method is that the reaction conditions are mild and the yield is acceptable; however, there are also deficiencies, the peroxide cost is higher, and the post-treatment is slightly more complex.
Second, the hydrogen peroxide-tungstic acid system is oxidized. Place the substrate containing 4-pyridyl in the reaction vessel, add an appropriate amount of hydrogen peroxide as the oxidizing agent, and tungstic acid or its salt as the catalyst. The reaction conditions of this system are relatively mild, and hydrogen peroxide is more common and the cost is slightly lower. During the reaction, the solvent can be selected from a mixed system of water and organic solvents, such as methanol-water, ethanol-water, etc. The reaction temperature should not be too high, usually between 40 ° C and 60 ° C. During the reaction, the reactive oxygen species produced by the decomposition of hydrogen peroxide attack the pyridine nitrogen atom and realize oxidation. Similarly, the reaction is monitored by TLC. When the raw material is completely converted, the target product can be obtained through extraction, separation, purification and other processes. The advantage of this method is that the raw material is easy to obtain and the cost is controllable; the disadvantage is that the reaction time is sometimes long, and the catalyst needs to be used precisely.
Third, electrochemical oxidation method. Construct a suitable electrochemical cell, use a compound containing 4-pyridyl as the substrate, and select suitable electrode materials, such as platinum electrodes, graphite electrodes, etc. An appropriate amount of supporting electrolyte is added to the electrolyte, and the electrolysis reaction is carried out at a specific potential. During this process, an oxidation-reduction reaction occurs on the surface of the electrode, so that the pyridyl nitrogen atom can be oxidized. The beauty of electrochemical oxidation is that it is green and environmentally friendly, and there is no need to add a large amount of additional chemical oxidants; however, the equipment requirements are high, and the reaction parameters need to be fine-tuned, such as potential, current density, reaction time, etc., to obtain the ideal yield and purity.

During the use of 4-aminopyridine and its\ (N -\) oxides, it is necessary to pay more attention to many matters.
First, it is related to safety protection. These two may be toxic and irritating, and can cause damage to the human body if they touch the skin, eyes or inhale their dust and vapor. Therefore, when operating, be sure to wear appropriate protective equipment, such as gloves, goggles and gas masks, to fully protect yourself. If it is accidentally touched, rinse with plenty of water immediately and seek medical treatment in a timely manner.
Second, it involves storage requirements. Store it in a cool, dry and well-ventilated place, away from fire and heat sources. Due to its flammability, it should be stored separately from oxidants, acids, etc., and must not be mixed to prevent dangerous chemical reactions. At the same time, the storage area should be equipped with suitable materials to contain leaks.
Third, about the use of specifications. Before use, it is necessary to have a detailed understanding of its nature, use and potential hazards. Operate in strict accordance with the operating procedures, and precisely control the amount of use and reaction conditions. If used in chemical reactions, it is necessary to fully consider its impact on the reaction process, product purity, etc., and carefully select suitable reaction solvents, catalysts, etc., to ensure the smooth progress of the reaction and obtain the expected products.
Fourth, pay attention to environmental impact. If these two enter the environment, or cause harm to the ecology. During use, waste should be properly disposed of and not discarded at will. Waste gas, wastewater, etc. generated should be treated in accordance with relevant environmental protection standards to ensure that they meet discharge standards to reduce negative impact on the environment.