3-Amino-4-pyridinecarboxylic acid

3-Amino-4-methoxybenzoic acid, although it has no name in "Tiangong Kaiwu", it is based on the ancient pharmacology and chemical theory, or it can be used.
At the pharmacological end, the ancient healers emphasized the properties of grass, wood, gold and stone to adjust the yin, yang and qi of the human body. The amino and methoxy structures of this acid may have unique chemical activities. Ancient physicians used medicine, often taking the properties of various substances in combination to treat diseases. Amino is alkaline, or can be neutralized with acidic substances in the body to adjust the acid-base balance of the human body, to treat diseases such as epigastric acid inversion, humid tropical zone, etc. Its reason is the use of basic drugs such as squid bone and oyster shell. The presence of methoxy groups may affect the lipophilic properties of drug molecules and help them better penetrate human tissues and exert their medicinal effects. This is similar to the ancient recipes that often used alcohol and vinegar to make drugs to increase their permeability.
In the chemical industry, "Tiangong Kaiwu" is detailed in the general process. This acid may be used in dye synthesis. Ancient dyeing, much depends on natural dyes, but the fastness and richness of color may not be sufficient. The special structure of 3-amino-4-methoxybenzoic acid may be used as a precursor for the synthesis of new dyes. Based on it, through chemical reaction, dyes with bright color and good fastness can be obtained, which can be used for dyeing silk, hemp and other fabrics to meet the pursuit of clothing color by the ancients, just like the blue indigo dyeing method in the book, and constantly improved for better results. Or used in the paint making process, adding this acid may improve the performance of the paint, making it more wear-resistant and corrosion-resistant, just like today's chemical additives, to improve product quality.

3-Amino-4-nitrobenzoic acid is an organic compound. Its physical properties are as follows:
Viewed, this compound is in a yellow crystalline shape, with bright color and regular morphology under natural light, showing typical crystalline material characteristics.
The melting point is between 234 ° C and 236 ° C. In this temperature range, the substance will transform from solid to liquid state. This property can be used as an important basis for judgment in experimental operations such as identification and purification of substances.
Its solubility also has characteristics. It is slightly soluble in cold water, but its solubility increases in hot water. This shows that temperature has a significant impact on its solubility. In practical applications, according to this characteristic, the dissolution and precipitation of the substance can be achieved by controlling the temperature to achieve the purpose of separation and purification. In addition, it is also soluble in organic solvents such as ethanol and ether. This property makes it possible to use it as a reactant or product in the field of organic synthesis, and to carry out related chemical reactions or separation operations with the help of these organic solvents.
These physical properties of 3-amino-4-nitrobenzoic acid have laid a solid foundation for its application in chemical research, drug synthesis, material preparation and many other fields. With its unique physical properties, scientists are able to ingeniously design experimental programs and give full play to their characteristics to meet the practical needs of different fields.

3-Amino-4-nitrobenzoic acid is one of the organic compounds with the following chemical properties:
1. ** Acidic **: Its molecule contains a carboxyl group (-COOH), which can dissociate hydrogen ions (H 🥰) in water, making it acidic. According to the acid-base theory, it can neutralize with bases, such as with sodium hydroxide (NaOH). The hydrogen ion in the carboxyl group combines with hydroxide ion (OH) to form water to form the corresponding carboxylate, that is, 3-amino-4-nitrobenzoate sodium and water. The reaction formula is: 3-amino-4-nitrobenzoic acid + NaOH → 3-amino-4-nitrobenzoic acid + H2O O.
2. ** Amino reaction **: Amino (-NH2O) is alkaline and can react with acids to form salts. If reacted with hydrochloric acid (HCl), the lone pair of electrons on the amino nitrogen atom can accept hydrogen ions and generate 3-amino-4-nitrobenzoic acid hydrochloride. The reaction formula is: 3-amino-4-nitrobenzoic acid + HCl → [3-amino-4-nitrobenzoic acid-H] 🥰 Cl. And the amino group can undergo acylation reaction, interact with acylating reagents such as acyl halide or acid anhydride, and the amino-hydrogen atom is replaced by an acyl group to form an amide compound. This reaction can be used to protect the amino group or introduce a specific functional group.
3. ** Nitro reaction **: Nitro (-NO -2) has strong electron absorption, which reduces the electron cloud density of the phenyl ring and causes the activity of the electrophilic substitution reaction of the phenyl ring to decrease. However, the nitro group can undergo a reduction reaction. Under suitable conditions, if iron filings and hydrochloric acid are used as reducing agents, it can be gradually reduced to amino groups. First, the nitro group is reduced to nitroso (-NO), and then reduced to amino groups. This reaction is often used in the preparation of polyamino compounds in organic synthesis.
4. ** Reaction of benzene ring **: Although the electrophilic substitution activity is reduced under the influence of nitro groups, electrophilic substitution reactions can still occur under certain conditions. Because amino groups are ortho-and para-sites and nitro groups are meta-sites, the two work together to make the subsequent electrophilic substitution reactions mainly occur at the ortho-sites of amino groups and the para-sites of nitro groups. Common electrophilic substitution reactions include halogenation, nitration, sulfonation, etc.

To prepare 3-amino-4-methoxybenzoic acid, there are various methods. First, p-methoxybenzoic acid can be started. First, it is nitrified with mixed acids (nitric acid and sulfuric acid) to obtain 4-methoxy-3-nitrobenzoic acid. In this step, sulfuric acid is used as a catalyst to help nitric acid generate nitroyl positive ions to attack specific positions of the benzene ring. After that, iron powder and hydrochloric acid or hydrogen and palladium carbon are used as reducing agents to convert nitro groups into amino groups to obtain the target product.
Second, 4-methoxyaniline can also be started from. After diazotization, sodium nitrite and hydrochloric acid are used at low temperature to obtain diazonium salts. Then it reacts with the cyanide solution of cuprous cyanide and potassium cyanide to introduce a cyanyl group to form 4-methoxy-3-cyanoaniline. Finally, the cyanyl group is hydrolyzed under the catalysis of acid or base to change it to a carboxyl group, and 3-amino-4-methoxybenzoic acid is also obtained.
There is another way to use p-methoxybenzaldehyde as a raw material. First, it is condensed with nitromethane to obtain 4-methoxy-3-nitrobenzene. Then the steps of reduction and oxidation are carried out. The reduction of nitro groups to amino groups, oxidized side chain double bonds and aldehyde groups, etc. are gradually converted into carboxyl groups, and then the required 3-amino-4-methoxybenzoic acid is synthesized. Each method has its advantages and disadvantages, and it is necessary to choose the appropriate one according to the actual situation, such as the availability of raw materials, the difficulty of reaction conditions, and the high cost.

The question I heard from you is about the price range of 3-amino-4-methoxybenzoic acid in the market. However, the price of this drug often changes due to various factors, making it difficult to determine.
First, it is about its quality. If the quality is good and the standard is strict, the price will be high; if the quality is flat, the price will be slightly lower. Second, it depends on the output and demand. If the product is abundant and the price is small, the price may drop; if the product is thin and prosperous, the price will rise. Third, the cost of production is also a factor. The price of raw materials, the simplicity of the process, and the amount of energy consumption all affect the price.
Generally speaking, in the chemical raw material market, the price per kilogram or between tens of yuan and hundreds of yuan. If it is used in high-end fields such as pharmaceutical research and development, the price can reach more than 1,000 yuan per kilogram after refining and high quality. However, this is only a rough estimate. The actual price should be obtained by consulting the latest quotations of chemical raw material suppliers, pharmaceutical companies, or participating in industry trading platforms.