5-Bromo-2-chloro-3-nitropyridine

5-Hydroxy-2-mercapto-3-furanopyridine, although this substance is not clearly recorded in Tiangong Kaiwu, its use can be deduced according to the methods of ancient people's exploration and application of various substances.
In the field of ancient medicine, some doctors may explore its characteristics to see if it has medicinal value. Because ancient doctors often tasted all kinds of herbs and various substances to see what effect it has on human diseases. If this substance has specific chemical properties, it may act on human qi and blood, viscera, adjust the imbalance of yin and yang, and treat various diseases, such as clearing heat, detoxifying, removing blood stasis, etc.
In ancient alchemy, alchemists often mixed and calcined various substances in order to seek longevity pills and rare treasures. If 5-hydroxyl-2-mercapto-3-furanylpyridine is one of the raw materials, or because of its special chemical composition, under high temperature and specific ingredients, a wonderful chemical reaction occurs to generate new substances, or it is an ingredient of "magic pill" pursued by warlocks, or it is a material with different characteristics.
Furthermore, although there is no modern fine chemical industry in ancient times, it also uses the characteristics of natural substances in dyes, tanning and other processes. If this substance has color and luster, it can react with other substances, or it can be used for dyeing to give fabrics a unique color and fastness; or in leather treatment, it can help leather tanning and improve leather quality and durability. Although the "Tiangong Kaiwu" is not detailed, the ancient people's exploration of the spirit of matter may have made it useful in many fields.

To make 5-hydroxyl-2-aldehyde-3-furanyl-acrylic, there are three methods.
First, furfural is used as the beginning, and the method of hydroxyaldehyde condensation is used. First, furfural and acetaldehyde are placed in an alkaline environment, such as in a dilute sodium hydroxide solution, with moderate temperature control, and the two play a role in condensation. The aldehyde group interacts with the α-hydrogen atom to obtain 3- (2-furanyl) -2-acrylic. Then, with a suitable reducing agent, such as sodium borohydride, in an alcohol solvent, the aldehyde group of the alkenyl aldehyde is reduced to obtain 5-hydroxyl-2-aldehyde-3-furanyl propene. The reaction conditions are easier to control, and the raw materials are common. However, the steps are slightly complicated, and the separation of the product may be difficult.
Second, by the method of organometallic reagents. Based on furan derivatives, a suitable halogen atom, such as a bromine atom, is first introduced to obtain halogenated furans. Later, it is prepared with an organomagnesium reagent, such as a Grignard reagent. Then this reagent is reacted with a suitable substrate containing aldehyde groups and hydroxyl groups in an anhydrous and oxygen-free environment. After the reaction is completed, the target product can be obtained by post-treatment steps such as hydrolysis. This method has good selectivity, but organometallic reagents are sensitive, preparation and use need to be cautious, and strict requirements on the reaction environment.
Third, the method of biosynthesis. Microorganisms or enzymes with specific enzyme systems can be found, with suitable carbon and nitrogen sources, under suitable culture conditions, so that microorganisms can metabolize and synthesize. Or directly use purified enzymes to construct reaction systems in vitro. The biosynthesis method has the advantages of green, high efficiency and excellent selectivity, but the process of bacterial species screening and culture, enzyme purification and immobilization is complicated and costly.

The physical properties of 5-hydroxyl-2-mercapto-3-pyridyl are as follows:
The color state of this object is usually colorless to light yellow crystals or crystalline powders, and it is fine in appearance. It has good stability at room temperature. When encountering hot topics, open flames or strong oxidants, it is necessary to be cautious, for fear of dangerous changes.
When it comes to the melting point, it is about [X] ° C. This property allows it to change its shape within a specific temperature range, from solid to liquid, just like ice and snow melting when warm. The boiling point is about [X] ° C. When the temperature rises to such a height, it will turn into a gaseous state and dissipate, like a cloud rising.
In terms of solubility, it dissolves slightly in water, just like raindrops merging into rivers, but it is not completely integrated, and only has a certain solubility; in organic solvents, such as ethanol, acetone, etc., the solubility is better, just like fish get water, and it is easier to disperse and fuse.
The density is about [X] g/cm ³, this value indicates that its weight per unit volume is heavier or lighter than some substances, and it is also one of its unique physical identifiers.
In addition, this object may have a slightly special smell, although it is not pungent or intolerable, but it is also unique, such as a light fragrance, but it is not a genus of floral and fruity fragrance. It is difficult to name it exactly, and it needs to be personally smelled to understand. Its appearance is fine and uniform, and the crystals or powders are regular and orderly, revealing the delicate microstructure, which is like a carefully crafted structure from nature.

5-Hydroxy-2-mercapto-3-furanylpyridine is an organic compound with the following chemical properties:
** acidity and alkalinity **: In this compound, the hydroxyl group (-OH) can exhibit acidity under specific conditions and can dissociate hydrogen ions (H 🥰), which is attributed to the high electronegativity of oxygen atoms, which attracts strong hydrogen-oxygen bond electron clouds, making hydrogen easy to leave in the form of ions. The nitrogen atom in the pyridine ring has a lone pair of electrons, which can accept protons and exhibit a certain alkalinity. Therefore, the compound has both acid and base amphoteric, and can react with acids and bases respectively.
** Redox property **: The sulfur atom in the thiol group (-SH) in the molecule is in a low oxidation state, with strong reducing property, and is easily oxidized by oxidants. For example, when it encounters common oxidants such as hydrogen peroxide, the thiol group can be oxidized to disulfide bonds (-S-S -), or even further oxidized to sulfonic acid groups (-SO-H). At the same time, if the pyridine ring encounters a strong reducing agent, its unsaturated structure may undergo hydrogenation and reduction reaction, causing the pyridine ring to be partially or completely hydrogenated.
** Nucleophilic Substitution and Electrophilic Substitution Reactivity **: As an aromatic system, the pyridine ring has an uneven distribution of electron cloud density because the electronegativity of nitrogen atoms is greater than that of carbon atoms. The electron cloud density at the α and γ positions is relatively low, showing electrophilicity, which is vulnerable to attack by nucleophilic reagents and occurs nucleophilic substitution reactions. The oxygen atoms and sulfur atoms on the hydroxy and sulfhydryl groups are rich in lone pair electrons and have nucleophilic properties, which can participate in nucleophilic substitution reactions as nucleophilic reagents. In addition, under specific conditions, the pyridine ring can also undergo electrophilic substitution reactions, but due to the electron-withdrawing effect of nitrogen atoms, its electrophilic substitution reaction activity is lower than that of the ben
** Coordination **: Both the sulfur atom of the thiol group and the nitrogen atom of the pyridine ring can provide lone pairs of electrons, which can form coordination bonds with metal ions as ligands to form complexes. This coordination ability may have important applications in the field of catalysis, separation and detection of metal ions.

Wen Jun's inquiry is about the price range of 5-hydroxy- 2-amine-3-quinazoline in the market. However, the price of these substances, or involving the fields of medicine and chemical industry, varies with quality, quantity, source and market conditions, and it is difficult to determine its fixed number.
If the quality is high and the mass production is abundant, the supply exceeds the demand, and the price may decline; on the contrary, if the quality is thin and the prosperity is sought, the price will tend to rise. And it may be used in scientific research and pharmaceuticals. For different purposes, its purity requirements are different, and the price is also different. For scientific research users, high purity is often sought, and the price must be higher than that of general industrial users. < Br >
And its price is also affected by geography. If the origin is close and convenient, the price will be low; if the origin is far and difficult, the price will be high. Coupled with market fluctuations, such as changes in raw material prices and policy regulation, the price can rise and fall.
Although it is difficult to determine the price, it can be deduced: in common commercial specifications and quality, the price may be in the range of several dollars to two silvers per catty. However, this is only an idea. The actual price still needs to be consulted with pharmaceutical companies and chemical companies before it can be determined.