3-Aminopyridine-4-carboxaldehyde

The main uses of 3-hydroxypyridine-4-formonitrile are many. In the field of medicine, it is a key intermediate for the synthesis of many drugs. For example, in the preparation of some antibacterial drugs, the unique chemical structure of 3-hydroxypyridine-4-formonitrile can be converted into structural fragments with antibacterial activity through specific reactions, providing a key basis for the development of new antibacterial drugs. It also has important applications in the research and development of anti-tumor drugs. Through a series of chemical reactions, compounds that can act on specific targets of tumor cells can be constructed, which can help the creation of new anti-tumor drugs.
In the field of pesticides, it can be used to synthesize pesticides with high insecticidal and bactericidal properties. With its chemical properties, it can react with other compounds to generate pesticide components that have good control effects on crop diseases and insect pests. For some common crop pests, pesticides synthesized by 3-hydroxypyridine-4-formonitrile can precisely act on the physiological system of pests, interfering with their normal growth and reproduction, thus achieving efficient control and relatively small negative impact on the environment.
In the field of materials science, 3-hydroxypyridine-4-formonitrile can be used as a synthetic raw material for functional materials. For example, when preparing materials with special optical and electrical properties, it can participate in the reaction to form specific structural units, giving the material unique properties. For example, the synthesis of materials with specific fluorescence emission characteristics can be used in optical sensors and other fields to detect and identify specific substances or physical quantities with high sensitivity.

There are many ways to synthesize 3-aminopyridine and 4-methylpyridine, which are described in detail below.
First, the synthesis of 3-aminopyridine. One method is to use pyridine as the starting material and nitrate to obtain 3-nitropyridine. This reaction requires careful selection of nitrifying reagents, such as mixed acids (mixtures of nitric acid and sulfuric acid), and control of reaction temperature and time to prevent excessive nitrification. Then 3-nitropyridine is converted into 3-aminopyridine by reduction method. Commonly used reducing agents include iron powder and hydrochloric acid, hydrogen and metal catalysts (such as palladium carbon). Although the reduction system of iron powder and hydrochloric acid is lower in cost, the post-treatment is slightly more complex; the catalysis of hydrogen and palladium carbon is cleaner and more efficient, but the cost of palladium carbon is higher.
Second, starting from niacin, niacin is first converted to niacin ester, and then the aminolysis reaction converts the ester group to amino group to obtain 3-aminopyridine. In this process, the esterification reaction requires suitable catalysts and reaction conditions to improve the yield. The temperature, pressure and amount of ammonia during aminolysis also need to be precisely controlled.
As for the synthesis of 4-methylpyridine. The classical method is to use acetaldehyde, formaldehyde and ammonia as raw materials, and then react by condensation under the action of a specific catalyst. This reaction system is relatively complex, and the proportion of raw materials, reaction temperature and pressure need to be precisely regulated. The catalysts used are mostly acidic or basic catalysts, such as molecular sieves, metal oxides, etc. Different catalysts have a great influence on the selectivity and activity of the reaction.
Pyridine can also be used as a raw material, and methyl is introduced into the alkylation reaction to obtain 4-methyl pyridine. Commonly used alkylation reagents include halogenated alkanes such as iodomethane and chloromethane. The reaction needs to be carried out under basic conditions to promote the nucleophilic substitution of pyridine nitrogen atoms to halogenated alkanes. However, this reaction requires attention to regioselectivity. Due to the different reactivity at different positions on the pyridine ring, it is often necessary to increase the proportion of 4-position substituted products by selecting appropriate reaction conditions and catalysts.
All these synthetic methods have their own advantages and disadvantages, and practical applications need to be carefully selected according to specific requirements, such as the availability of raw materials, cost considerations, product purity requirements, etc.

Methyl ether is also an organic compound. Its physical properties are specific and worthy of in-depth investigation.
First of all, its phase and odor. At room temperature and pressure, methyl ether is gaseous, colorless and has a mild aroma unique to ethers. Although this smell is not pungent, it can accumulate in a closed space and can be noticed by people as a warning sign.
Second of all, its melting and boiling point. The melting point of methyl ether is -141.5 ° C, and the boiling point is about -24.9 ° C. The boiling point is very low, which makes it highly volatile at room temperature, and it quickly changes from liquid to gaseous. This is of great significance in practical applications, such as in the manufacture of aerosols. Methyl ether is easy to vaporize and spray due to its low boiling point, which provides power for the dispersion of the product.
In addition to solubility. Methyl ether is slightly soluble in water, but it can be miscible with most organic solvents, such as ethanol, ether, acetone, etc. This solubility characteristic is due to its molecular structure. Methyl ether molecules have a certain polarity, so they can dissolve with some polar organic solvents. This characteristic makes it used as a solvent or extractant in organic synthesis and chemical production.
Also known as its density. The density of methyl ether is less than that of air, about 1.97 kg/m ³ (the density of air is about 1.29 kg/m ³), because the relative molecular weight of methyl ether is small and the molecular spacing is large. During storage and use, if methyl ether leaks, because it is lighter than air, it will spread upward and accumulate in the upper part of the space. Special attention should be paid to this in terms of safety precautions.
In addition, methyl ether is flammable. It can form an explosive mixture when mixed with air. In case of open flame and high heat, it can cause combustion and explosion. This flammability is due to the presence of hydrocarbons in the molecules of methyl ether, which can react violently with oxygen under suitable conditions, releasing a large amount of energy. Therefore, in the production, storage and transportation of methyl ether, fire prevention and explosion prevention are the top priority.

4-Methyl ether, its chemical properties are as follows:
Methyl ether, a colorless flammable gas or compressed liquid, with a slight ether aroma. Stable under normal conditions, in case of hot topic, open flame or oxidant, there is a risk of explosion.
First, methyl ether can burn, burn in sufficient oxygen, generate carbon dioxide and water: $CH_3OCH_3 + 3O_2\ stackrel {ignited }{=\!=\!=} 2CO_2 + 3H_2O $, this property makes it can be used as fuel, combustion heat production, to provide energy.
Second, methyl ether can undergo a substitution reaction. Because of its structure, methyl groups are affected by ether bonds and have certain activity. For example, with halogens (such as chlorine gas $Cl_2 $) under light conditions, the hydrogen atom on the methyl group can be replaced by chlorine atoms to form products such as chloromethyl ether: $CH_3OCH_3 + Cl_2\ stackrel {light }{=\!=\!=} CH_2ClOCH_3 + HCl $.
Third, methyl ether can interact with strong acids. In case of strong acids such as concentrated sulfuric acid, ether bonds will break. If it reacts with concentrated sulfuric acid, methyl hydrogen sulfate is formed: $CH_3OCH_3 + H_2SO_4\ longrightarrow CH_3OSO_3H + CH_3OH $.
Fourth, methyl ether has weak Lewis alkalinity. Because the ether bond oxygen atom contains lone pairs of electrons, it can provide electron pairs to form complexes with Lewis acids. In the case of boron trifluoride $BF_3 $, the lone pair of electrons of the oxygen atom can coordinate with the empty orbit of the boron atom to form a complex: $CH_3OCH_3 + BF_3\ longrightarrow (CH_3) _2O\ cdot BF_3 $.
In summary, methyl ether has chemical properties such as combustion, substitution, reaction with strong acids and Lewis alkalinity, which make it suitable for use as fuel and organic synthesis in the chemical industry.

Mercury, a highly toxic substance, must be stored and transported with caution.
The most important thing for storage is to choose a place. When placed in a remote and cool place, avoid all kinds of heat sources and open flames to prevent it from evaporating when heated, causing the danger of poisoning. Its place should be dry and do not allow water vapor to invade it, because mercury is prone to chemical reactions with water, damaging its quality, and may cause other unexpected changes.
Storage utensils must also be carefully selected. Heavy glass bottles are commonly used, tightly sealed to prevent their leakage and escape. If using metal utensils, avoid copper, iron and other substances, because it is easy to combine with mercury and cause mercury to mutate. The outside of the bottle should be marked with "highly toxic" and other warning words, so that everyone who sees it knows the danger.
When transporting, the mercury should be properly wrapped and lined with a thick and soft object to prevent it from being damaged by shock. The person handling it must choose someone who is familiar with its nature, is cautious, and wears protective gear, such as gloves, masks, etc., to avoid direct contact with mercury.
The transportation vehicle should also be clean and dry, free of mixing with other objects, to prevent mercury from changing. During driving, it is advisable to drive slowly and steadily to avoid bumps and vibrations and keep the mercury safe.
If there is a slight carelessness in the storage and transportation room, and the mercury escapes, it should be disposed of as soon as possible. Shoot everyone to avoid taking its poison. Quickly cover it with sulfur powder to dissolve mercury sulfide and reduce its toxicity, and then collect it carefully and dispose of it properly.
In short, the storage and transportation of mercury is related to human life safety, and everything must be done with caution.