1H-imidazole-4,5-dicarbonitrile, 2-bromo-

The physical properties of 4,5-diene are quite unique and are of great significance in many fields. Although this substance has not been recorded in detail in Tiangong Kaiwu, it can be roughly deduced according to the methods of ancient learning.
4,5-diene is mostly gaseous or liquid under normal circumstances, and its boiling point and melting point are different due to the characteristics of molecular structure. The double bond structure within the molecule causes the intermolecular forces to be different. Generally speaking, the boiling point is slightly lower than that of alkanes with the same number of carbon atoms. Due to the existence of double bonds, it is difficult for the molecules to be closely arranged, and the intermolecular dispersion force is weakened. The melting point is also affected by a similar effect, but it is still related to the symmetry of the molecule. If the molecule has a certain symmetry, the lattice arrangement is more regular, and the melting point may be relatively high.
Its density is also closely related to the structure. Due to the existence of double bonds, the volume of the molecule may change, which in turn affects the density. Compared with saturated hydrocarbons with the same number of carbon atoms, the density is usually smaller, because the double bond makes the molecule more compact and the mass per unit volume is reduced.
4,5-diene is mostly insoluble in water, because water molecules are connected by hydrogen bonds, forming a relatively close structure. And 4,5-diene is a non-polar or weakly polar molecule, and the force between it and water molecules is weak, making it difficult to break the hydrogen bond between water molecules and dissolve into it. However, it is soluble in some organic solvents, such as benzene, carbon tetrachloride, etc., due to the principle of "similar miscibility". Organic solvents are mostly non-polar or weakly polar, and are mutually soluble with 4,5-diene molecules.
Furthermore, the refractive index of 4,5-diene is also characterized by the conjugation effect of double bonds. The conjugated system can enhance the fluidity of the electron cloud, produce specific refraction and absorption of light, and the refractive index may be different from that of ordinary hydrocarbons. This property is of great value in analysis and identification.

The chemical properties of 4,5-diene are quite unique, with multiple wonderful properties, which play a key role in many chemical reactions.
First, 4,5-diene contains a carbon-carbon double bond, which gives it significant unsaturation. Just as "Tiangong Kaiwu" says "things have a beginning and an end, things have a beginning", the carbon-carbon double bond is the fundamental beginning of the chemical properties of 4,5-diene. Because of its unsaturation, 4,5-diene is prone to addition reactions, which can be combined with many electrophilic reagents such as halogens and hydrogen halides like rivers converging. Taking bromine as an example, it can be added to 4,5-diene smoothly, the double bond is broken, and the bromine atom is respectively connected to the carbon atom connected by the original double bond. This is a typical example of electrophilic addition, as if everything is in harmony with each other and follows the established laws.
Second, the conjugation effect also plays a crucial role in the chemical properties of 4,5-diene. The existence of a conjugate system allows the electron cloud to be delocalized and the molecular stability to be improved, like a stable structure. This results in the unique activity of 4,5-diene in some reactions. For example, in the Diels-Alder reaction, 4,5-diene, as a diene body, reacts synergistically with the diene body to construct a new carbon-carbon bond. This reaction is like a precise tenon-and-mortise structure, which is precise and efficient, providing an extremely important way for the construction of cyclic compounds in organic synthesis.
Third, 4,5-diene can also carry out oxidation reactions. Depending on the oxidant, the product also varies. Just like different tools, different utensils can be created. Under the action of mild oxidants, products such as alcohols and alaldehyde may be formed; while under the action of strong oxidants, carbon-carbon double bonds may be completely broken, forming more oxidized products such as carboxylic acids.
Fourth, due to the reactivity of double bonds, 4,5-diene can be polymerized under appropriate conditions. Many 4,5-diene molecules are connected to each other to form long-chain polymers, which are like many small silk threads woven into a grand cloth, providing novel raw materials for the field of materials science and widely used in synthetic rubber.
The rich chemical properties of 4,5-diene play an indispensable role in many fields such as organic synthesis and material preparation, opening up a vast world for the development and application of chemistry.

Although 4,5-dialdehyde-1H-pyrazole-2-carboxylic acid did not have this specific chemical substance in the era mentioned in Tiangong Kaiwu, its main use can be inferred from similar uses in ancient times. In ancient times, related substances with similar structures or properties may be related to dyeing, medicine, alchemy, etc.
In terms of dyeing, natural dyes were highly valued in ancient times. Many substances containing special functional groups can be used as dyes to color fabrics. If 4,5-dialdehyde-1H-pyrazole-2-carboxylic acid existed at that time, the aldehyde group and carboxyl group contained in it could chemically react with fabric fibers to achieve good dyeing effect. Like the common indigo dyeing in ancient times, it is to use the principle of combining specific substances with fabrics. This substance may be used for dyeing in this way to give fabrics a specific color.
In medicine, ancient doctors specialized in natural medicines. Many compounds containing specific groups have medicinal value, such as clearing heat and detoxifying, promoting blood circulation and removing blood stasis. The aldehyde and carboxyl groups of 4,5-dialdehyde-1H-pyrazole-2-carboxylic acids may interact with substances in the body to exhibit antibacterial, anti-inflammatory and other properties, and are used to treat diseases. The ancients had limited knowledge of the active ingredients of herbs and relied on experience to accumulate, but similar structural substances may have potential applications in the field of medicine.
In the field of alchemy, ancient alchemists were keen on alchemy in order to achieve immortality or to refine miraculous medicinal pills. The alchemy process involves many chemical reactions, often using substances containing a variety of functional groups. If 4,5-dialdehyde-1H-pyrazole-2-carboxylic acid exists, its special structure may be used as a raw material or catalyst in alchemy reactions, participating in complex chemical changes and helping alchemists obtain the desired effect of alchemy. Although the purpose of alchemy is unscientific, it has promoted the development of ancient chemistry to a certain extent.

There are many methods for synthesizing 4,5-dialdehyde-1H-pyrazole, each with its own advantages. The following is a detailed description of Jun.
One is the oxidation method. A suitable oxidizing agent can be selected to act on the substrate containing the corresponding group. For example, using a specific alcohol derivative as the starting material, using an oxidizing agent, such as a mild Dess-Martin oxidant or a more common potassium permanganate, etc., to oxidize it to promote the conversion of alcohol hydroxyl groups into aldehyde groups to construct a 4,5-dialdehyde-1H-pyrazole structure. The key to this method is to precisely control the reaction conditions, such as temperature, pH, and the amount of oxidant. If the temperature is too high, it may cause excessive oxidation and the formation of unnecessary by-products; improper dosage will also affect the yield and purity of the reaction.
The second is the cyclization method. The chain compound with suitable substituents is first prepared, and then under suitable reaction conditions, it undergoes an intramolecular cyclization reaction. For example, by carefully designing the chain precursor containing functional groups such as nitrogen and aldehyde groups, under the catalysis of acids or bases, the intracellular ring formation is induced, and the target pyrazole ring structure is formed. In this process, the choice of catalyst is crucial, and different catalysts may lead to differences in reaction paths and rates, which need to be carefully selected according to the characteristics of the substrate.
The third is to use compounds containing pyrazole rings for functional group transformation. If there is a parent structure containing a pyrazole ring, an aldehyde group can be introduced to its 4,5 positions by means of a specific chemical reaction. For example, by halogenation, halogen atoms are first introduced at the 4,5 positions of the pyrazole ring, and then metal reagents are reacted with corresponding aldehyde reagents to achieve the introduction of aldehyde groups. However, this method is relatively cumbersome, and it is necessary to finely separate and purify the intermediates in each step of the reaction in order to ensure the quality of the final product.
The above methods have their own advantages and disadvantages. In actual synthesis, the optimal synthesis path should be carefully selected according to various factors such as the availability of raw materials, the difficulty of the reaction, and the purity requirements of the target product.

4,5-Disaccharide is used in storage and transportation, so everyone should pay attention.
Disaccharide, which is a dimer of carbohydrates, performs energy storage and material transport in living organisms. During storage, the first environmental conditions. Temperature and humidity are related to the stability of disaccharide. If the temperature is too high, the disaccharide may cause structural changes due to heat and accelerate decomposition; if the humidity is too high, it is easy to absorb moisture and deliquescence, breed microorganisms, and cause it to deteriorate. Therefore, it is necessary to choose a dry and cool place to store it, such as in a low-temperature dry storage to ensure its quality.
Furthermore, light also has an impact. Light can cause photochemical reactions of disaccharides, destroy their molecular structure, and damage their biological activity. Therefore, the storage of disaccharides should be protected from light, or wrapped in shading materials to reduce the amount of light they receive.
As for transportation, shock resistance is the key. Disaccharides are mostly crystals or powders, which are bumpy and vibrate or cause changes in their physical form, and even agglomerate, which affects subsequent use. Transportation tools need to run smoothly, and the goods should be properly fixed to mitigate vibration and shock.
At the same time, isolation and protection are indispensable. Disaccharides should be isolated from odorous, toxic and harmful substances. Because of their certain adsorption, they are easy to absorb surrounding odors, and come into contact with harmful substances, or react chemically, endangering quality and safety.
In addition, the transportation time limit also needs to be considered. Although the disaccharide is relatively stable, it will be affected by external factors during long-term storage. Therefore, it is necessary to plan a reasonable transportation route and time to deliver it to the destination as soon as possible. In this way, the characteristics and functions of 4,5-disaccharide can be preserved during storage and transportation, so that it can play its due role in biological metabolism and industrial applications.