3-bromo-4-nitropyridine

The main use of 3-4-pyridinone, as reported in "Tiangong Materials", is mostly used for smelting and dyeing.
In the process of smelting, 3-4-pyridinone can be used as a special aid. In ancient times, it was often encountered in the process of stone extraction. With this material added to the smelting process, it can produce specific chemical reactions in the stone. It can make the stone more easily melted in the slag, making the metal extraction more effective, and the resulting gold products are better. For example, it can reduce the harmful properties such as sulfur and phosphorus contained in the stone, so that the performance of the stone can be improved, and it can be used to create excellent equipment.
When it comes to dyeing, 3-4-pyridinone is also a wonderful use. Ancient dyeing, if you want to have a long-lasting color, you need to work hard. With this dyeing process, it can be used as a medium for dyeing. It can form a chemical reaction for dyes and dyes, and increase the fastness of dyes. In this way, the dyed material can be washed for a long time and is not easy to fade, and the color is new for a long time. For example, using a medium dyer containing 3-4-pyridinone can dye a beautiful color, such as dye, Diqing, and can ensure that the color of the dye is clear under daily use and monthly invasion. Therefore, it is important in dyeing.

The synthesis of 3-bromo-4-fluorobenzoic acid is an important topic in the field of organic synthesis. The following are common methods:
First, halogenated aromatics are used as starting materials. A suitable halogenated benzene derivative can be selected first, and the corresponding aryl ketone can be formed by introducing an acyl group through the Fu-gram reaction. For example, 3-bromo-4-fluorobenzene is used as a raw material, catalyzed by Lewis acid such as anhydrous aluminum trichloride, and reacted with acetyl chloride and other acylating reagents to obtain 3-bromo-4-fluorobenzophenone. Subsequently, a haloform reaction is used to convert the acetyl group into a carboxyl group under basic conditions. This process requires attention to the control of the reaction conditions. Too strong or too weak alkalinity may affect the yield and selectivity of the reaction.
Second, cross-coupling reaction catalyzed by palladium. Coupling reaction occurs with borates or halogenated aromatics containing bromine or fluorine as substrates and suitable halogenated aromatics or borates in the presence of palladium catalysts and ligands. For example, with 3-bromobenzoic acid derivatives and 4-fluorohaloaromatic hydrocarbons, under the action of tetra (triphenylphosphine) palladium and other catalysts, in a suitable solvent, at a certain temperature, a carbon-carbon bond is formed, and the basic skeleton of the target molecule is constructed. After that, the necessary functional group conversion of the obtained product is carried out to obtain 3-bromo-4-fluorobenzoic acid. This method requires quite high reaction conditions, and the choice of catalysts and ligands is crucial, which will significantly affect the reactivity and selectivity.
Third, starting from simple aromatic hydrocarbons, halogen atoms and carboxyl groups are gradually introduced. The aromatic hydrocarbon is first halogenated, and suitable halogenating reagents, such as brominating agents, fluorinating agents, etc., can be selected. Under specific conditions, bromine atoms and fluorine atoms are selectively introduced into the aromatic hydrocarbon to form aromatic hydrocarbon derivatives containing bromine and fluorine. Then, through oxidation reaction, such as strong oxidants such as potassium permanganate and potassium dichromate, under appropriate acid-base conditions, the side chains of aromatic hydrocarbons are oxidized to carboxyl groups. However, in this process, attention should be paid to the stability of halogen atoms under oxidation conditions to avoid the shedding of halogen atoms or other side reactions.
All synthesis methods have their own advantages and disadvantages, and they need to be carefully selected according to the actual situation, such as the availability of raw materials, the difficulty of controlling reaction conditions, and cost considerations, in order to achieve efficient and economical synthesis of 3-bromo-4-fluorobenzoic acid.

The physical properties of 3-hydroxy- 4-pyridinone are as follows:
This substance is mostly crystalline at room temperature, with a white and pure color, like the first snow in winter, delicate and shiny. Its shape is regular, and it is often shown in the state of regular crystals, which is quite beautiful.
Its smell is weak, and it is close to a fine smell, only to have a touch of elegance, no pungent smell, and does not disturb people's sense of smell.
The melting point is moderate. At a specific temperature, it is like ice melting in spring, slowly turning from solid to liquid. This temperature is about [X] degrees Celsius, which makes it useful in some processes that require precise temperature control. < Br >
In terms of solubility, it has a certain solubility in water, just like fish entering water, it can be well dispersed and form a uniform state; it can also be dissolved in common organic solvents such as ethanol and acetone, showing good solubility. This property makes it easy to blend with other substances in many chemical reactions and preparations to exert its efficacy.
The density is slightly heavier than that of water, and it is placed in water, such as a stone sinking abyss, slowly sinking, with a density of about [X] grams/cubic centimeter. This property makes it unique in practical operations such as separation and storage. < Br >
Its texture is relatively hard, and although it is not as strong as gold and stone, it is not easy to crush easily. It can change its shape under a certain external force. During storage and transportation, it can maintain its own structural integrity and reduce the character changes caused by external impact.

The chemical properties of 3-4-pyridyl groups are rich, which is described in ancient Chinese.
This group has weak properties. Because the nitrogen atom of pyridyl groups has unformed molecules, it can accept molecules. However, its fatty amine properties are weak, and the density of molecules of pyridyl groups is reduced due to the co-effect of molecules. In case of acid, it can be formed. This is the characteristic of its acid reaction.
It is also nuclear. The oxygen atom of the group and the nitrogen atom of the pyridyl group all contain solitary molecules, which can be easily attacked under suitable conditions. For example, in some synthetic antibodies, pyridine can be substituted for antibodies, and the solitary child of the pyridine nitrogen atom can attack the carbon atom of the pyridine nitrogen atom and remove the element to form a new carbon-oxygen or carbon-nitrogen.
In addition, this group also has certain oxidizing properties. The alkyl group can be oxidized, and it can be oxidized to an aldehyde group, a carboxyl group, etc. Pyridine can also be oxidized under specific conditions. For example, the original pyridine can be partially or completely oxidized, and its chemical properties can be changed.
Furthermore, 3-4-pyridine groups can be formed. The atom of a pyridine group can be used as a source, while the pyridine nitrogen atom can be used as a recipient. This property makes it play an important role in molecular interactions. It affects the physical properties such as melting and solubility, and also has a deep impact on the interaction and interaction of other molecules in biology. In addition, the general properties of 3-4-pyridyl groups make it useful in many fields such as synthesis, physicochemistry, and materials science.

Today, there are three and four categories, which are determined by the quality of the city. The quality of the product is not due to its importance, but also involves the reasons for the situation.
If it is the value of the expected, the supply and demand of the city, the quality of the construction, and even the quality of the world's bureau and decrees can all affect it. If the material is abundant, the supply and demand can be met, and the quality of the product can be reduced or slightly reduced; if it is made of high quality, the quality of the product can be improved, or it can be increased due to rarity.
It is ancient, and it also has its own culture and history. If it is in a special period, or has special features and characters, it can also make the product floating. Or because of the scarcity of the existing quantity, it affects the market.
However, if you want to state the quality of the product, it will be fine. Generally speaking, if you use high-quality materials and ordinary forms, there will be a difference between three or four or four. However, if special factors are involved, the four levels will be slightly more due to the use of materials, or slightly less than one level. However, this is all a rough guess, and it depends on the quality and background of the product, etc., or there is a large difference between the materials, and it is uniform.