3-Iodo-2-Aminopyridine

The main uses of amine groups are in the fields of pharmaceuticals, dyes, and pesticides.
In the pharmaceutical industry, amine groups are the key components. Many drug molecules contain amine structures, because they can interact with specific targets in organisms, and play a therapeutic effect by binding to receptors and inhibiting enzyme activity. For example, antibiotics, by binding amine groups to targets in bacteria, interfere with the normal physiological metabolism of bacteria and achieve the purpose of antibacterial; anti-histamine drugs, by the action of amine groups and histamine receptors, relieve allergic symptoms.
In the industry of dyes, amine groups endow dyes with excellent properties. First, amine groups can enhance the affinity between dyes and fibers, making dyes easier to adsorb on fibers and improve dyeing fastness. Second, the amine group has electron-giving properties, which can change the conjugated structure of dye molecules, thereby adjusting the color and spectral properties of dyes. Many direct dyes and acid dyes contain amine groups, which enable effective dyeing of fabrics.
In the pesticide industry, amine groups are also important. Some pesticides contain amine-based structures, which interact with biological macromolecules in pests and pathogens to poison or inhibit their growth. Insecticides use amine groups to bind to targets in the insect's nervous system, interfering with nerve conduction and causing insect death; fungicides use amine groups to interact with pathogenic bacteria cell walls, cell membranes or enzymes to inhibit the growth and reproduction of pathogenic bacteria.
In addition, amines are also used in materials science, surfactants and other fields. In materials science, amine groups can be used for polymer modification to improve polymer properties; in surfactants, amine groups can give surfactants special properties, such as cationic surfactants containing amine groups, with bactericidal, antistatic and other effects.
From this perspective, amine groups are widely used, play a key role in many industries, and have a profound impact on human life and production.

Amine is a very important group in organic compounds, and there are many synthesis methods. Although "Tiangongkai" does not elaborate on the synthesis of amine groups, the synthesis of amine groups in the field of chemistry is as follows:
1. ** Halogenated hydrocarbon aminolysis **: Halogenated hydrocarbons react with ammonia or amine under suitable conditions, and halogen atoms are replaced by amino groups. If chloroethane is co-heated with excess ammonia, ethylamine can be obtained: $C_ {2} H_ {5} Cl + NH_ {3}\ xrightarrow {\ Delta} C_ {2} H_ {5} NH_ {2} + HCl $. This reaction mechanism is nucleophilic substitution. The nitrogen atom of ammonia has a lone pair of electrons. It is a nucleophilic reagent that attacks the α-carbon atom of halogenated hydrocarbons, and the halogen ions leave.
2. ** Reduction of nitriles **: The amine group can be obtained by reducing the nitrile compound. The commonly used reducing agent is lithium aluminum hydride ($LiAlH_ {4} $) or catalytic hydrogenation. For example, acetonitrile is reduced with lithium aluminum hydride to produce ethylamine: $CH_ {3} CN\ xrightarrow {LiAlH_ {4}} CH_ {3} CH_ {2} NH_ {2} $. The hydrogen anion in lithium aluminum hydride has strong reductivity and attacks the carbon atom of the nitrile group. Amine is obtained through a series of reactions.
** Amide reduction **: Amids can also be reduced to amines by lithium aluminum hydride. For example, acetamide is treated with lithium aluminum hydride to generate ethylamine: $CH_ {3} CONH_ {2}\ xrightarrow {LiAlH_ {4}} CH_ {3} CH_ {2} NH_ {2} $. In this process, the carbonyl group of the amide is reduced to methylene, and the nitrogen atom is retained to form an amine group.
4. ** Gabriel synthesis method **: React potassium phthalimide with halogenated hydrocarbons to generate N-alkyl phthalimide, and then hydrolyze or hydrazinolyze to obtain a pure primary amine. For example, potassium phthalimide reacts with bromoethane, and the product is hydrazinolyzed to obtain ethylamine. This method can avoid the formation of secondary amines and tertiary amines.
5. ** Reductive amination **: Aldides or ketones and ammonia or amines first form imines, and then reduce to amines. Taking formaldehyde and methylamine as an example, imines are formed first, and then reduced with sodium borohydride to form dimethylamines: $HCHO + CH_ {3} NH_ {2}\ xrightarrow {} [CH_ {2} = NCH_ {3}]\ xrightarrow {NaBH_ {4}} (CH_ {3}) _ {2} NH $. This reaction condition is mild and widely used.

Amine groups have unique physical properties. Most of them are basic, because nitrogen atoms have lone pairs of electrons and can accept protons. Simple amines such as ammonia have a pungent smell and have a certain solubility in water because they can form hydrogen bonds with water molecules.
The boiling point of an amine group is related to the molecular structure. Small amines have a higher boiling point due to hydrogen bonding; however, with the increase of alkyl groups, the intermolecular dispersion force becomes stronger, and the effect of hydrogen bonding is slightly weaker. For example, the boiling point of methylamine is about -6.3 ° C, while the boiling point of ethylamine is about 16.6 ° C.
Furthermore, the solubility of amine groups is also interesting. Low-grade fatty amines are soluble in water because they can form hydrogen bonds with water; however, higher-grade fatty amines have increased hydrophobicity and reduced solubility due to the increase of hydrocarbon groups. Aromatic amines, such as aniline, have poor solubility in water due to the hydrophobicity of the benzene ring, but are soluble in organic solvents such as ethanol and ether.
Looking at their density, fatty amines are generally less than water, and aromatic amines are more than water. For example, the density of aniline is 1.0216 g/cm ³, which is greater than the density of water. The physical properties of
amine groups are of great significance in various fields such as chemicals and pharmaceuticals. Because of its alkalinity, it can be used to neutralize acidic substances; its solubility and boiling point also affect the choice of separation, purification and reaction conditions. Therefore, understanding the physical properties of amine groups is the basis for exploring amine-containing compounds, and it is also a key factor for the development of related industries.

All those who need to be careful when repairing and storing the amido-base.
It is appropriate to store the amido-base in the first place. The amido-base is prone to melting when exposed to light, moisture, and damp. Therefore, when it is stored, it is appropriate to avoid dryness and light isolation, so as to protect its properties. And it is also necessary to isolate acids, acids, oxides, etc., in order to prevent their chemical properties from changing and causing reactions.
Furthermore, the container should not be used. It is appropriate to use materials with good corrosion resistance and sealing properties, such as glass and special plastics, which can not only protect it from external invasion, but also prevent leakage.

If the amino group is not only unstable, but also endangers the surrounding things, and is even more harmful to people.
It is necessary to ensure its safety first. It is necessary to ensure that it does not shake and collide, so as to prevent the container from breaking.

In addition, those who do this must be aware of the problem and handle it properly. When operating, wear anti-damage equipment, such as gloves, masks, and eyes, to prevent accidental contact, and yourself.
Therefore, it is necessary to be careful in the storage of amines, to be careful in the heart, to observe the micro-details, and to follow the general conditions, in order to ensure its safety and appropriate application.

Amine groups are very important functional groups in organic compounds, and there are many chemical reactions related to them. From the perspective of "Tiangong Kaiwu", they are explained as follows:
First, acylation reaction. Amine groups can interact with acylation reagents such as acyl halides and acid anhydrides. In case of acyl halides, the nitrogen atom in the amine group has a lone pair of electrons, and the nucleophilicity is quite strong. It can attack the carbonyl carbon of the acyl halogen, and the halogen atom leaves to form an amide. Its text says: "When an amine encounters an acyl halogen, nitrogen has a lone pair of electrons. Nucleophilic and attacks the carbon of the carbonyl group. When the halogen atom leaves, it forms a genus of amides." This reaction is very important in organic synthesis, and can be used to prepare a variety of amide compounds. Amids are widely used in many fields such as medicine and materials.
Second, alkylation reaction. Amino groups can react with alkylation reagents such as halogenated hydrocarbons. The solitary pair electron of the nitrogen atom attacks the carbon atom of the halogenated hydrocarbon, and the halogen ion leaves, and the hydrogen on the amine group is replaced by an alkyl group. Such as "Amino-halogenated hydrocarbons, the solitary pair electron of nitrogen is nucleophilized to its carbon and halogen ions, and the hydrogen is replaced by an alkyl group." Through this reaction, the amine group can be modified to change the properties and functions of the compound, and it is commonly used in the synthesis of various nitrogen-containing organic compounds.
Third, react with nit Different types of amines react with nitrous acid differently. Primary amines react with nitrous acid to form diazonium salts. This reaction is carried out at low temperatures, and diazonium salts have high reactivity. Many subsequent reactions can occur, such as the coupling reaction of diazonium salts, which can prepare a variety of azo compounds, which is of great significance in dye synthesis. Secondary amines react with nitrous acid to form N-nitroso compounds. Tertiary amines and nitrous acids generally form only salts. For example: "Primary amines meet nitrous acid and form diazonium salts. This should be done at low temperatures. The activity of diazonium salts is very high, which can initiate various subsequent reactions, such as the coupling reaction, the production of azoides, and the combination of dyes is very important. Secondary amines react with nitrous acid to produce N-nitroso compounds. Tertiary amines and nitrous acids often form only salt ears. "
Fourth, condensation reaction. Amino groups can condensate with the carbonyl groups of aldides and ketones to form imines or enamines. Such as amines and aldides, nitrogen atoms nucleophilic attack the carbonyl carbon of aldides, and through a series of proton transfer processes, form imines." Amine and aldehyde, nitrogen nuclei attack the carbon of aldehyde carbonyl, and through proton transfer, form imines. "Imine is also an important intermediate in organic synthesis and can be further converted into various nitrogen-containing compounds.