3-Amino-2-pyridinecarboxylic acid

3-Amino-2-hydroxybenzoic acid, also known as 3-aminosalicylic acid, its main uses are as follows:
This substance is widely used in the field of medicine. Because it has certain pharmacological activity, it can be used as a key intermediate for the synthesis of many drugs. For example, in the development of anti-tuberculosis drugs, it plays an important role. Tuberculosis is an ancient disease. Although medicine is prosperous today, it has not dared to slack off in the research of anti-tuberculosis drugs. 3-Amino-2-hydroxybenzoic acid can undergo a series of subtle chemical reactions and combine with other chemical groups to construct drug molecular structures with unique anti-tuberculosis effects. < Br >
In the dye industry, it also has a place. Due to its molecular structure characteristics, it can be converted into a dye intermediate with excellent performance through a specific process. The dyes made are bright in color and have good fastness. The ancient art of dyeing and weaving has long-lasting color, and the same is true today. Dyes made from 3-amino-2-hydroxybenzoic acid can be widely used in the dyeing of textiles, making fabrics colorful and satisfying the world's pursuit of beauty in clothing and fabrics.
Furthermore, in the field of organic synthesis, it is often used as an important starting material. Chemists use its amino groups, hydroxyl groups, carboxyl groups and other reactive groups to carry out various organic reactions. By ingeniously designing reaction paths, complex and diverse organic compounds can be synthesized, contributing to the development of organic synthetic chemistry. Just as the ancient alchemists carefully prepared elixir recipes in order to refine magical things, today's organic synthesis also adheres to this spirit of exploration, using raw materials such as 3-amino-2-hydroxybenzoic acid to create many novel organic products.

3-Amino-2-hydroxybenzoic acid, also known as anthaminosalicylic acid, is a kind of organic compound. It has the following physical properties:
- ** Properties **: Under normal circumstances, it is a white to light yellow crystalline powder, which is delicate in appearance and can be discerned by the eye. This form sign is quite important in material identification and preliminary cognition. It is just like a person's appearance and is a first impression.
- ** Melting point **: About 140 - 143 ° C. When the temperature rises, the state of the substance changes from solid to liquid. This melting point characteristic is like an accurate ruler, which is indispensable in the identification of purity and the study of material characteristics. It can be used to measure whether the substance is pure, just like measuring the substance to know its weight.
- ** Solubility **: Slightly soluble in cold water, but good solubility in hot water, ethanol, ether, and ethyl acetate. This difference in solubility is just like people's choice of residence, and it has different adaptations in different environments. It is not easy to integrate in cold water, but in hot water and alcohol ether esters, if it is in a suitable environment, it will blend harmoniously. This characteristic is a key consideration in the process of separation, purification, and preparation. According to its solubility, a suitable solvent can be selected to achieve the desired purpose. < Br > - ** Odor **: Odorless or slightly odorous, with a slightly bitter taste. Smell and taste, although their taste and smell are not material key properties, they are also one of the ways to recognize them. Just like human temperament, although invisible but perceptible, in practical applications, smell and taste may affect their application in food, medicine and other fields.

3-Amino-2-hydroxybenzoic acid is an organic compound. It is acidic because its carboxyl group can ionize hydrogen ions. In a chemical reaction, the carboxyl group can neutralize with bases to form carboxylic salts and water.
The amino group in this compound is basic and can react with acids to form corresponding salts. Amino groups can also participate in various reactions such as amidation, by interacting with acylating reagents to form amide compounds.
Hydroxyl groups are active and can undergo substitution reactions, such as reacting with halogenated hydrocarbons to form ether compounds. At the same time, hydroxy groups can participate in esterification reactions and react with carboxylic acids under acid catalysis to form esters and water. < Br >
The structure of the benzene ring endows the substance with certain stability, and the benzene ring can undergo electrophilic substitution reactions, such as halogenation, nitration, sulfonation, etc. Because the amino group and the hydroxyl group are ortho and para-sites, the electrophilic substitution reaction mainly occurs in the ortho and para-sites of the benzene ring.
3-Amino-2-hydroxybenzoic acid is widely used in the field of organic synthesis because it has a variety of active groups. It can be used as a synthesis intermediate for fine chemicals such as medicines, dyes, and pesticides, providing key starting materials for the preparation of many compounds.

To prepare 3-amino-2-naphthoic acid, there are three methods.
First, start with 2-naphthoic acid, and go through nitration and reduction. First, 2-naphthoic acid is heated with mixed acid, and the reaction of nitration is carried out to obtain 3-nitro-2-naphthoic acid. This step requires moderate temperature control. Because the activity of the naphthalene ring is high, if the temperature is too high, it is easy to produce polynitrogenides. Later, iron powder and hydrochloric acid or sodium sulfide are used as reducing agents to convert the nitro group into an amino group, and then 3-amino-2-naphthoic acid is obtained. The raw materials in this way are easy to obtain, but the selectivity of the nitrification step is poor, and there are many by-products, and the separation is complicated. < Br >
Second, the method of carboxylation with 2-naphthalene amine as a group. In a suitable solvent, the carboxylation reaction of 2-naphthalene amine and carbon dioxide under high temperature and pressure and a catalyst occurs, and the target product can be obtained. This process requires harsh conditions, specific high-pressure equipment, and quite strict requirements for the reaction device. However, its atomic economy is good, there are few side reactions, and the product purity is expected to be higher.
Third, naphthalene is used as the starting material and is converted in multiple steps. Naphthalene is first halogenated to obtain halogenated naphthalene, and then carboxyl groups are introduced through the Fu-gram reaction, after which nitrification, and finally nitro is reduced to amino groups. Although there are many steps in this route, the reaction conditions in each step are relatively mild, and the reagents used are common However, due to the lengthy steps, the total yield is easily affected, and the separation and purification work of each step in the process cannot be ignored.
All these methods have advantages and disadvantages. In actual preparation, it is necessary to weigh many factors such as raw material availability, cost, product purity and equipment conditions.

I have heard your inquiry about the price of 3-hydroxy-2-naphthoic acid in the market. The price of such things in the market often varies according to the quality, quantity, and state of supply and demand.
If it is of high quality, it is an excellent product, and if it is abundant, its price may be high. However, if the quality is average, the quantity is also normal, and the price may be moderate. In today's city, the price of this product or per catty is between tens and hundreds of dollars.
Because everything in the world is based on supply and demand. If there are many people in need, and there are few people in supply, the price will increase; if the supply exceeds the demand, the price will be reduced. And the cities of various places have different terroirs and soils, which also makes the price different.
In the cities of various places, the north and south are different, and the east and the west are also different. Or because of the distance of the road, the difficulty of transportation makes the price change. Therefore, if you want to know the exact price, you should visit the cities in person and consult the merchants. Although the domain of the price I say is for your reference only, the feelings of the city change, in an instant, you should not be bound by this statement.