3-pyridinecarboxylic acid, 2-fluoro-4-iodo-

3-Amino, 2-ene-4-yne has a wide range of uses and plays a key role in many fields.
In the field of organic synthesis, it can be used as a key intermediate. With its unique structure, 3-amino can participate in many nucleophilic substitution reactions, laying the foundation for the construction of nitrogen-containing organic compounds; the unsaturated bond between 2-ene and 4-yne endows it with rich reactivity. For example, in the construction of complex cyclic compounds, the 2-ene-4-alkyne part can cooperate with other functional groups through cyclization reaction to form a unique cyclic structure. For example, with the help of a variant of the Diels-Alder reaction, it reacts with suitable dienophiles to synthesize cyclic alkyne compounds with special structures, providing a key step for the total synthesis of natural products.
In terms of materials science, 3-amino, 2-ene-4-alkyne can be used to prepare functional polymer materials. 3-amino can be polycondensed with monomers with active groups such as carboxyl groups and acyl chlorides, and the introduction of alkyne structures can endow polymer materials with special optical and electrical properties. For example, in the synthesis of conjugated polymers, the alkyne-conjugated structure helps to delocalize electrons, thereby improving the photoelectric properties of materials. It may be applied to organic Light Emitting Diode (OLED), solar cells and other fields to improve the absorption and conversion efficiency of materials to light.
In the field of pharmaceutical chemistry, such compounds also have potential value. 3-amino groups can interact with targets in organisms through hydrogen bonds, etc., to enhance the affinity of drugs and targets; 2-ene-4-alkyne structures can participate in some biotransformation processes in vivo or irreversibly bind to specific protein targets, thus playing a therapeutic role. For example, compounds with 3-amino and 2-ene-4-alkyne as parent nuclei can be designed and structurally modified to screen out lead compounds with anti-tumor and antiviral activities, providing direction for the development of new drugs.

The physical properties of 3-hydroxypropionic acid, 2-alkene-4-alkyne are as follows:
###3-hydroxypropionic acid
1. ** Properties **: Usually colorless to light yellow viscous liquid, its appearance is more translucent at room temperature, the texture is thicker, similar to honey but relatively better fluidity.
2. ** Melting point and boiling point **: The melting point is about 61 ° C, and the boiling point is about 213 ° C. The melting point is relatively low, and it can be converted from solid to liquid at slightly higher than normal temperature; the boiling point is higher, indicating that the intermolecular force is stronger, and it requires higher energy to turn it into a gaseous state.
3. ** Solubility **: Easily soluble in polar solvents such as water, ethanol, and ether. This is because 3-hydroxypropionic acid molecules contain hydroxyl groups, which can form hydrogen bonds with water molecules. At the same time, the polarity of its molecules is also matched with polar solvents such as ethanol and ether, making it have good solubility in these solvents.
4. ** Density **: The relative density is about 1.26 (water = 1), which is slightly higher than the density of water. If it is mixed with water, it will sink to the bottom in a static state.
##2-ene-4-alkyne
1. ** Properties **: It is a colorless gas at room temperature and pressure, odorless or slightly special odor, and it is difficult for the naked eye to detect its existence. It needs to be detected by special instruments or sensed by chemical reactions.
2. ** Melting point and boiling point **: The melting point is low, about -108 ° C, and the boiling point is about 29 ° C. Such a low melting point and relatively low boiling point indicate that its intermolecular force is weak, and it exists in a gaseous state at room temperature, and it can be turned into a liquid state with only a little cooling, and it becomes a solid state with further cooling.
3. ** Solubility **: Slightly soluble in water, soluble in organic solvents such as benzene, carbon tetrachloride, etc. Since its molecular structure is mainly composed of carbon-carbon double bonds and carbon-carbon triple bonds, it is non-polar or weakly polar, and the interaction with strong polar molecules such as water molecules is weak, so the solubility in water is small; and it can dissolve with non-polar or weakly polar organic solvents.
4. ** Density **: The relative density (air = 1) is about 1.38, which is higher than the density of air. If released in an open space, it will sink and accumulate in a lower position, which may cause safety hazards in some specific environments, such as the formation of combustible gas accumulation areas in low-lying areas with poor ventilation.

The chemical properties of 3-hydroxy, 2-alkene-4-alkyne are as follows:
hydroxy ($- OH $), which is active. First, it can react with active metals such as sodium metal to produce hydrogen gas. For example, ethanol reacts with sodium to generate sodium ethanol and hydrogen. The hydroxyl bond in this hydroxyl group is broken, and sodium replaces the hydrogen position. Second, it can undergo esterification reaction, and carboxylic acid forms an ester and water under the condition of catalysis of concentrated sulfuric acid and heating. For example, acetic acid reacts with ethanol to form ethyl acetate. In this process, the hydroxyl group is dehydrogenated, and the carboxyl group is dehydrogenated. The two combine to form water, and the rest are connected to form an ester. Third, the hydroxyl group can also undergo a elimination reaction. When there is a hydrogen atom on the adjacent carbon atom of the carbon atom of the hydroxyl group, under the heating condition of concentrated sulfuric acid, a molecule of water is removed to form an unsaturated bond. The carbon-carbon double bond of
2-ene is quite active. On the one hand, an addition reaction can occur, which is added with hydrogen gas, halogen elements, hydrogen halide, etc. For example, ethylene reacts with bromine water, one of the carbon-carbon double bonds breaks, and two bromine atoms are added to the two carbon atoms to make the bromine water fade. On the other hand, an addition polymerization reaction can be carried out. Under certain conditions, the double bonds are opened and connected to each other to form a polymer compound, such as ethylene addition polymerization to form polyethylene. < Br >
4 - The carbon-carbon triple bond of alkyne also has unique chemical properties. It can also undergo an addition reaction. When added to hydrogen, if there is enough hydrogen, it can be added to alkanes; if there is insufficient hydrogen, it can be added to alkanes. It can also be added to halogen elements, hydrogen halides, etc. In addition, the carbon-carbon triple bond can also undergo an oxidation reaction, which can fade the acidic potassium permanganate solution and be oxidized to compounds containing carboxyl groups.
This compound combines hydroxyl groups, carbon-carbon double bonds and carbon-carbon triple bonds. The functional groups interact with each other, or make some reaction activities different, or introduce new reaction paths. Its chemical properties are rich and it is of great significance in the field of organic synthesis and other fields.

To prepare 3-pentenoic acid and 2-bromo-4-pentanone, you can combine it according to the following ancient method.
First take an appropriate amount of pentanone and react with bromine. In a suitable reactor, control the temperature moderately and slowly drop bromine. The carbonyl ortho-hydrogen of pentanone has a certain activity and can be substituted with bromine to generate 2-bromo-pentanone. This step requires attention to the dripping rate of bromine and the reaction temperature. If the temperature is too high, polybromination by-products may be formed. < Br >
After obtaining 2-bromo-pentenone, place it in a reaction vessel with an appropriate amount of alkali solution, and heat it to promote its elimination reaction. The base can capture the hydrogen at the ortho-position of the bromine atom, and the bromine ions leave at the same time, so 2-pentenone is obtained. In this process, the concentration of the base, the reaction temperature and time need to be precisely controlled to obtain 2-pentenone with a higher yield.
Then, carboxylation of 2-pentenone is carried out. Suitable reagents, such as carbon monoxide and suitable catalyst systems, can be selected. Under specific reaction conditions, carbon monoxide is inserted into the carbon-carbon double bond, and then carboxyl groups are introduced to obtain 3-pentenoic acid. In this step, factors such as the choice of catalyst, the pressure of carbon monoxide and the reaction temperature have a great influence on the reaction process and product yield.
As for the preparation of 2-bromo-4-pentanone, pentanone can be enolized first, and pentanone can be formed into enol negative ions with a suitable base, and then reacted with bromine reagents to introduce bromine atoms at the 4th position to obtain 2-bromo-4-pentanone. During the reaction, the type and dosage of bases, the activity of brominated reagents and the reaction solvent need to be carefully considered to optimize the reaction path and improve the purity and yield of the product.
In this way, the required 3-pentenoic acid and 2-bromo-4-pentanone can be prepared by following these methods.

3-Amino, 2-ene-4-alkynes are useful in many fields.
In the field of medicinal chemistry, 3-amino can endow compounds with unique activity and create key structures for new drugs. The presence of 2-ene and 4-alkynes can change the spatial configuration and electron cloud distribution of compounds, and increase their affinity and selectivity with biological targets. For example, when synthesizing small molecules with anti-cancer activity, fragments containing 3-amino and 2-ene-4-alkynes can precisely act on cancer cell-specific proteins, block cancer cell proliferation signaling pathways, and achieve anti-cancer effects.
In the field of materials science, 3-amino reactivity is high, which can be used as a connection point to construct high-performance polymer materials. The 2-ene-4-alkyne structure can improve the mechanical properties and thermal stability of materials through polymerization or cross-linking reactions. For example, the preparation of high-strength fiber materials, the introduction of this structure can enhance the intermolecular force and greatly improve the tensile strength of fibers.
In the field of organic synthesis chemistry, 3-amino and 2-ene-4-alkyne are important functional groups. They can participate in a variety of organic reactions, such as cyclization reactions, addition reactions, etc., to synthesize complex organic compounds. By rationally designing reaction routes and utilizing their characteristics, organic molecules with special structures and functions can be efficiently constructed, providing rich strategies and methods for organic synthesis.
In catalytic chemistry, metal catalysts containing 3-amino and 2-ene-4-alkyne ligands can modify the activity and selectivity of catalysts. The unique electronic effects and steric resistance of these ligands make the catalysts exhibit excellent performance in specific reactions, promoting efficient and green chemical reactions.