4-Quinolinecarboxylicacid, 6-hydroxy-

4-Hydroxybenzoic acid, the chemical properties of 6-amino groups, are quite complicated, let me come one by one.
4-Hydroxybenzoic acid, acidic, because its carboxyl group can release protons. In water, the carboxyl group is partially dissociated and weakly acidic, which is why it can form salts with bases. Its hydroxyl groups also have certain activity and can participate in many reactions. In the case of electrophilic reagents, the adjacent and para-position of the hydroxyl group are vulnerable to attack, because the hydroxyl group is the power supply group, which increases the density of electron clouds in the adjacent and para-position of the benzene ring, and is easily attacked by electrophilic reagents. Common electrophilic substitution reactions such as halogenation and nitrification occur mostly in the adjacent and para-position of the hydroxyl group. < Br >
6-amino group, the amino group is a basic group, because the nitrogen atom has a lone pair of electrons, which can bind protons, and is weakly basic in aqueous solution. If the 6-amino group is connected to the benzene ring and other systems, the amino group is the power supply group, which can cause the electron cloud density of the benzene ring to increase, and affect the reactivity and check point selectivity on the benzene ring. For example, in the electrophilic substitution reaction, the amino group increases the electron cloud density of the benzene ring o and the para-site significantly, and the electrophilic reagent is easy to attack the o and para-site.
If 4-hydroxybenzoic acid and 6-amino group coexist in the same compound, they affect each other. The electron-withdrawing effect of the carboxyl group may weaken the alkalinity of the amino group, while the electron-donating effect of the amino group can enhance the acidity of the hydroxyl group. The existence of these two groups makes the compound have both acidic and basic parts, and can participate in acid-base neutralization, electrophilic substitution and other chemical reactions. In organic synthesis, medicinal chemistry and other fields, it is often a key activity check point, which affects the properties and functions of the compound. It is of great significance in many reaction mechanisms and practical applications.

What are the main users of 4-hydroxybenzoic acid and 6-amino group? These two are important in medicine, chemical industry and other fields.
In the field of medicine, 4-hydroxybenzoic acid is often used as a preservative and can be added to pharmaceutical preparations to prevent the growth of microorganisms and ensure the quality and stability of drugs. It has certain antibacterial properties, can effectively inhibit the growth of bacteria and fungi, and ensure that drugs are not contaminated by microorganisms during storage. And 6-amino is also an important pharmaceutical intermediate, and many drug synthesis relies on it as a starting material or key structural unit. For example, in the preparation of some antibiotics and anti-cancer drugs, 6-amino participates in specific reactions to construct drug active structures, which has a great impact on drug efficacy.
In the chemical industry, 4-hydroxybenzoic acid can be used to synthesize polyester resins, polyether resins and other polymer materials. Such materials have excellent mechanical properties, thermal stability and chemical stability, and are widely used in plastics and fiber manufacturing. Polyester fibers made from it are crisp and anti-wrinkle, easy to wash and dry, and are widely used in the textile industry. 6-Amino is used in dye synthesis, which is an important component in the production of a variety of bright colors and good fastness dyes. After chemical modification and reaction, it can give specific properties of dyes to meet the diverse needs of textile, printing and dyeing industries.
In addition, in the field of daily chemicals, 4-hydroxybenzoic acid is also used as a preservative in cosmetics and skin care products. Can maintain product quality, extend shelf life, and ensure user safety. 6-amino groups have emerged in the research and development of some functional materials, such as for the preparation of materials with special adsorption and separation properties, and have received increasing attention in the fields of environmental protection and chemical separation.

To prepare the compound of 4-pentenoic acid and 6-amino group, there are three methods.
One is the enylation method. First, take glutaric anhydride and carefully reduce it with lithium aluminum hydride to obtain pentanediol. Following the catalysis of sulfuric acid, heat dehydration to obtain 4-pentenol. Then oxidize it to 4-pentenal with a mild oxidizing agent, such as manganese dioxide, and finally oxidize the aldehyde group with Toran reagent or Feilin reagent to obtain 4-pentenoic acid. As for the 6-amino part, the corresponding halogenated hydrocarbons and ammonia or amine compounds can be introduced into the amino group in an appropriate solvent by heating reaction, and then condensed with 4-pentenoic acid to obtain the target product. This process requires fine control of the reaction conditions of each step, because the ethylene bond may affect the subsequent reaction conditions.
The second is the rearrangement method. With a suitable halogenated valerate as the starting material, under basic conditions, an intramolecular rearrangement reaction occurs to construct the 4-pentenoic acid structure. At the same time, compounds containing amino groups, such as amino acid ester derivatives, are selected to form the 6-amino part through a series of reactions such as ester exchange and hydrolysis. In the end, the two can obtain the desired compounds through reactions such as condensation and bonding. Although this path has many steps, it can precisely regulate the structure, and the key lies in the separation and purification of the intermediate in each step.
The third is the biosynthesis method. Using specific microorganisms or enzyme systems, the appropriate carbon source and nitrogen source are used as substrates. For example, some bacteria with special metabolic pathways can gradually metabolize the carbon source to 4-pentenoic acid under specific culture conditions, and at the same time use the nitrogen source to introduce amino groups. This method is green and environmentally friendly, but it needs to screen suitable microorganisms or enzymes, and the reaction conditions need to simulate the in vivo environment of the organism. It requires high control of reaction equipment and conditions to ensure biological activity and reaction efficiency.

The solubility of 4-hydroxybenzoic acid and 6-amino group in different solvents varies.
In terms of water, 4-hydroxybenzoic acid can form hydrogen bonds with water because it contains carboxyl and hydroxyl groups. However, its benzene ring is a hydrophobic group, so it is slightly soluble in water at room temperature. When the temperature rises, the solubility increases slightly. If the 6-amino group is not assisted by other hydrophilic groups, although the amino group can form hydrogen bonds with water, the overall solubility is poor. Due to the different structures of amino compounds, some are slightly soluble, and most are insoluble in water.
In organic solvents, the polar 4-hydroxybenzoic acid in organic solvents such as ethanol and acetone has better solubility due to the principle of similar miscibility. Both ethanol and 4-hydroxybenzoic acid can form hydrogen bonds, and the intermolecular forces match, so they can be mutually soluble. If the 6-amino group is a fatty amine, it has a certain solubility in polar organic solvents, because the amino group can form a hydrogen bond with the solvent; if it is an aromatic amine, in non-polar organic solvents such as benzene and toluene, the solubility will be better than that in water due to the similar miscibility of the benzene ring.
In acidic solvents, the carboxyl group of 4-hydroxybenzoic acid will compete with the acid for protons, reducing its solubility in strong acidic solvents. In acidic solvents, the 6-amino group is easy to combine with protons to form ammonium salts, and the solubility is greatly increased. < Br >
In alkaline solvents, 4-hydroxybenzoic acid carboxyl groups can react with bases to form salts, which greatly improves the solubility in alkaline solvents. If the 6-amino group is alkaline, the solubility in the alkaline solvent is affected by the alkaline strength of the solvent, the strength of the amino base and other groups. If the alkalinity is weak, the solubility changes or is not obvious; if the alkalinity is strong, or due to factors such as the same ion effect, the solubility may change.

Today, there are four things called 4-pentenoic acid and 6-benzyl. What is the price range of the market? These two are widely used in the field of chemical industry. 4-pentenoic acid, with alkenyl and carboxyl groups, has strong activity. It is often used as a raw material in organic synthesis and can be used to make flavors and medicines. For 6-benzyl, benzyl is stable in nature and can be introduced into a specific structure. It is useful in the research and development of materials and drugs.
However, the price of the product is determined, and it is not a decision. One is related to supply and demand. If the market demand increases greatly, and the production is not enough, the price will rise; if the production is abundant and the demand is small, the price will drop. The second depends on the quality. Those who are of high quality, the price is always high; those who are of poor quality, the price will be low. The third is related to the origin and transportation. The origin is close to the city, and the transportation is convenient, and the cost will be saved, and the price may be appropriate; the origin is far away, and the transportation is difficult and expensive, and the price will be high.
Under normal circumstances, the price of 4-pentenoic acid is about a few hundred yuan per kilogram. Pure or high-quality, the price may be nearly a thousand yuan; and ordinary, it may be three or four hundred yuan. The price of 6-benzyl is also between several hundred yuan per kilogram. If it is of high purity, and contains very little impurities, and the craftsmanship is excellent, the price may be as high as seven or eight hundred yuan; if the quality is slightly inferior, the price may However, these are all approximate numbers. When market conditions change, prices also fluctuate, either from time to time or from city to city. Businesses should always observe market conditions to understand changes in prices.