4-nitropyridine-3-carbaldehyde

3-Aminopyridine-4-carboxylate ethyl ester, namely 3-amino-4-pyridinecarboxylate ethyl ester, its main uses are as follows:
This compound is widely used in the field of medicinal chemistry. The structural properties of Gainpyridine ring and amino and ester groups give it unique biological activities and pharmacological properties. In the development of new drugs, it is often used as a key intermediate. For example, when developing targeted drugs for specific diseases, different functional groups can be introduced through structural modification and modification to adjust the activity, selectivity and pharmacokinetic properties of the drug. For example, in the synthesis of some anti-tumor drugs, 3-amino-4-pyridinecarboxylate is used as the starting material to construct complex structures with anti-tumor cell proliferation activity through multi-step reactions.
In the field of organic synthetic chemistry, it is also an important synthetic building block. Because amino and ester groups can participate in a variety of classic organic reactions, such as amidation reaction, esterification reaction, nucleophilic substitution reaction, etc. With these reactions, they can be linked with other organic molecules to build a library of organic compounds with diverse structures, providing a rich material basis for materials science, total synthesis of natural products and other fields. For example, in the synthesis of organic materials with special photoelectric properties, 3-amino-4-pyridinecarboxylate can be integrated into the macromolecular structure through clever reaction design, giving the material unique optical and electrical properties.
In addition, in the field of pesticide chemistry, there are also potential applications. Pesticide products with high insecticidal, bactericidal or herbicidal activities can be developed with reasonable structure optimization, providing new and effective means for agricultural pest control and weed control.

There are many ways to make propane. One method is to react with carbonized water phase. Carbonized water, also known as stone, meets water and produces acetylene. And under the action of catalysis, the amount of acetylene is even higher, and propane can be obtained by partially adding propane. The reverse reason is that the catalytic power of the catalyst increases the resistance of acetylene, resulting in the formation of propane.
Another method starts with propylene. Propylene (such as chlorine and bromine) is first substituted for propene when it is suitable for use. And the action of propylene is eliminated, and propane can be generated. In this case, the force of the atom is to remove the atom from the carbon phase to form carbon trioxide, and propane is produced.
Furthermore, acetone can also be used as a raw material. Acetone is first produced from propane to obtain propane. Propane is then produced from water under specific catalytic and anti-chemical components. Propylene can also be obtained by following the above method of propylene-propane.
In addition, there are those who use propane as a starting material. Under the catalytic action of propane, propane is generated from water, and then replaced and eliminated in equal steps. Propane can also be produced.
Therefore, the method of making propargyne has its own reasons, and it requires factors such as the availability of raw materials, the level of cost, and the ease of reaction.

3-Aminopyridine, also known as β-aminopyridine, is an important organic compound. Its physical properties are quite characteristic, as follows:
- ** Appearance **: Under normal temperature and pressure, 3-aminopyridine appears as a colorless to light yellow crystalline powder. This appearance feature is clearly distinguishable, and it is easily recognized by the naked eye under general observation conditions, providing an intuitive basis for its preliminary identification in practical application and research.
- ** Odor **: It has a rather special odor, which is difficult to describe accurately, but has a certain degree of recognition. This odor characteristic can be used as an important clue for sensory recognition when operating and using it. < Br > - ** Melting point **: Its melting point is about 60-62 ° C. Melting point is a physical parameter of great significance and plays a key role in the purification, identification and control of related chemical reaction conditions of substances. By measuring the melting point, the purity of the substance and whether there are impurities can be effectively judged.
- ** Boiling point **: The boiling point is about 251-253 ° C. The boiling point data is extremely critical for the separation and distillation of substances. According to its boiling point, appropriate separation methods and conditions can be reasonably selected to achieve effective purification and purification of 3-aminopyridine.
- ** Solubility **: 3-aminopyridine is soluble in a variety of common solvents such as water, ethanol, ether, etc. This good solubility provides convenience for its application in different chemical reaction systems. In organic synthesis, the appropriate solvent can be flexibly selected according to the reaction requirements to ensure that 3-aminopyridine can fully participate in the reaction, thereby improving the reaction efficiency and yield.
- ** Density **: The density is about 1.16 g/cm ³. Density, as one of the basic physical properties of substances, plays an indispensable role in practical application scenarios such as the measurement, storage and transportation of substances. Accurate knowledge of its density is helpful to achieve accurate measurement and reasonable storage of 3-aminopyridine.

3-Ethylpyridine is an organic compound that is widely used in the chemical industry, medicine and other fields. Its chemical properties are rich and diverse, as detailed below:
###Basic
The pyridine ring contains nitrogen atoms and does not share electron pairs, making 3-ethylpyridine alkaline. It can react with acids to generate corresponding salts. For example, when reacting with hydrochloric acid, the unshared electron pairs on the nitrogen atom will accept protons and generate 3-ethylpyridine hydrochloride. This property is used in organic synthesis to separate and purify 3-ethylpyridine, and the purpose is achieved by changing its solubility after salting with acids.
###Nucleophilic Substitution Reaction
The electron cloud density distribution on the pyridine ring is uneven. Under certain conditions, the hydrogen atom on the 3-position ethyl group will be affected by the electron-absorbing effect of the pyridine ring and the activity will be enhanced, and the nucleophilic substitution reaction can occur. When there is a nucleophilic reagent, the nucleophilic reagent can attack the carbon atom on the ethyl group and cause the hydrogen atom to be replaced. For example, under the action of strong bases, 3-ethylpyridine can undergo nucleophilic substitution reaction with halogenated hydrocarbons, and the hydrogen on the ethyl group is replaced by the hydrocarbon group in the halogenated hydrocarbons, which provides a way to construct more complex organic molecular structures
###Oxidation reaction The ethyl group in
3-ethylpyridine can be oxidized. Under the action of suitable oxidants, such as strong oxidants such as potassium permanganate, ethyl may be gradually oxidized to carboxyl groups to form 3-pyridinecarboxylic acid. This oxidation reaction is often used in organic synthesis to prepare pyridine compounds containing carboxyl groups. These compounds are used as important intermediates in the fields of medicine and pesticides.
###Aromatic ring substitution reaction
Although the electron cloud density of the pyridine ring is lower than that of the benzene ring, the aromatic ring substitution reaction can still occur under certain conditions. For example, in the presence of a catalyst, 3-ethylpyridine can undergo a halogenation reaction with a halogenating reagent to introduce a halogen atom on the pyridine ring. However, due to the electron cloud distribution characteristics of the pyridine ring, the position selectivity of the substitution reaction is different from that of the benzene ring, and the reaction is usually more inclined to occur at the β-position (i.e. 4-position or 6-position) of the pyridine ring, which is essential for the synthesis of pyridine derivatives with specific substitution modes.

The price of the fish varies from time to time and from place to place. The change in its price is related to various reasons, so let me explain in detail.
The fish are born in rivers and lakes, like clear water, and eat meat bait. Every spring and summer, the water temperature gradually rises, and the fish are active, swimming in the shallows to feed. At this time, there are many catchers, and the number of people entering the market is also abundant. Therefore, the price often stabilizes, or even drops slightly. Looking at the city, the price per catty, or between 30 and 50 yuan, ordinary people can also buy and eat it to enjoy its freshness.
In autumn and winter, the weather is cold and the water is cold, and the fish dive into the deep pool, foraging is less and less, and fishing is difficult. And as the New Year is approaching, everyone wants to buy fish to offer sacrifices to their ancestors, relatives and friends, and the demand has increased greatly. The price of cayenne often rises. The market price can reach seventy to hundred dollars per catty, and even higher. In case of disaster years, floods and droughts, the production of cayenne decreases sharply, and the price of cayenne skyrockets, which is extraordinary for ordinary people.
In addition, the price of cayenne is also different in prosperous cities and remote towns. In the capital city, the population is dense, there are many wealthy households, and the diet is exquisite, so the demand for cayenne is very high. In addition to transportation costs and shop rents, the price is often high. In remote places, there are few residents and the demand is not strong. Although the cichlid is also a good food, the price may be slightly lower due to inconvenience in circulation.
As for the quality, it also affects its price. The price of cichlid with big body, fat body and bright color is higher than that of those with thin and dark colors. When people buy fish in the city, they are willing to pay a high price because the merchants also pay attention to quality and seek a good price.
To sum up, the price of cichlid in the market is subject to factors such as season, supply and demand, region, and quality, and fluctuates. Between sales, you need to look at the current situation in order to get the right price.