Benzoquinone compounds can be divided into two categories: o-benzoquinone and p-benzoquinone. Naturally occurring benzoquinone compounds are mostly p-benzoquinone derivatives. It is unstable due to the repulsion between the two carbonyl groups in the o-benzoquinone structure.

1. Naphthoquinones are a type of organic compounds, also called phthalic acid diester compounds. 2. They can absorb higher ultraviolet rays to protect them from possible Cancer effects of sunlight's ultraviolet rays. Due to this aspect, naphthoquinone compounds It is used as an additive in cosmetics, skin care products and other personal care products. Naphthoquinones are widely used as inhibitors against bacteria and fungi additives that can extend the shelf life of food and medicines.

Natural phenanthrenequinone is divided into two types: o-quinone and para-quinone. For example, a variety of phenanthrenequinone derivatives isolated from the roots of the traditional Chinese medicine Salvia miltiorrhizae belong to o-phenanthrenequinones and p-phenanthrenequinones.

Anthraquinone complexes occur naturally and can also be synthesized artificially. Anthraquinones include their products and dimers with different degrees of reduction, such as anthraphenol, oxidized anthraphenol, anthrone, etc., as well as glycosides of these compounds. Among natural products, anthraquinone often exists in the metabolites of higher plants and lower plants, lichens and fungi. Anthraquinones have hemostatic, antibacterial, purgative, and diuretic effects.

The anthraquinone core is substituted with hydroxyl, hydroxymethyl, methoxy and carboxyl groups, and exists in plants in the form of free or glycosides. According to the distribution of hydroxyl groups on the anthraquinone core, hydroxyanthraquinone derivatives can be divided into two categories. (1) Emodin type: The hydroxyl groups are distributed on the benzene rings on both sides, and most compounds are yellow to brown. For example, active ingredients with diarrheal effects such as rhubarb and knotweed often fall into this category. (2) Rubiacin type: The hydroxyl group is distributed on the benzene ring on one side. The color of the compound is darker, mostly orange-yellow to orange-red.

Color: Mostly yellow to orange-red solid, related to the number of auxiliary color groups Form: Mostly solid Fluorescence: Fluorescent, showing different colors at different pH values

Free anthraquinone has sublimability and can sublimate without decomposing when heated under normal pressure. Generally, the sublimation temperature increases with the increase of acidity. For example: chrysophanol ≈ chrysophanol methyl ether < aloe emodin < emodin < rhein

Solubility: Glycone: Strongly lipophilic, usually (easily) soluble in benzene, ether, and chloroform. It is also soluble in alkaline organic solvents such as pyridine and N-dimethylformamide. It is soluble in acetone, methanol and ethanol. Insoluble or poorly soluble in water. Oxyglycoside of anthraquinone: highly polar, easily soluble in methanol and ethanol, and also soluble in water, more soluble in hot water, but less soluble in cold water, almost insoluble in ether, benzene, chloroform and other solvents. Carbon glycoside of anthraquinone: its solubility in water is very small, it is difficult to dissolve in lipophilic organic solvents but is easily soluble in pyridine.

Quinone compounds mostly have phenolic hydroxyl or carboxyl groups, so they are mostly acidic. The acidity depends on whether there are carboxyl groups and the number and position of phenolic hydroxyl groups.

Kesting-Craven reaction (active methylene): When benzoquinone and naphthoquinone compounds have unsubstituted positions on their quinone rings, they can react with some active methylene reagents (such as acetoacetic acid) under alkaline conditions. Ester, malonate, malononitrile, etc.) alcohol solution reacts to produce blue-green or blue-violet. If there is a hydroxyl group substituted on the benzene ring of naphthoquinone, the reaction will slow down or not react. Anthraquinone compounds can be distinguished because they have benzene rings on both sides of the quinone ring and cannot undergo this reaction.

Colorless methylene blue color development test: Colorless methylene blue solution is a special color developer for benzoquinones and naphthoquinones. Blue spots, distinguished from anthraquinone compounds.

Borntrger reaction: Hydroxyquinones change color in alkaline solution, and the color will deepen when collected and organized by Aiai Medical Examination Center | Education Network. Mostly orange, red, purple and blue. Hydroxyanthraquinone and anthraquinone glycosides with free phenolic hydroxyl groups can display color, but anthraphenol, anthrone, and dianthrone compounds need to be oxidized to form hydroxyanthraquinone compounds before they can display color.

Feigl reaction: Quinone derivatives can react quickly with aldehydes and o-dinitrobenzene when heated under alkaline conditions to generate purple compounds.

Reaction with metal ions: In anthraquinone compounds, if there is an α-phenolic hydroxyl or o-diphenolic hydroxyl structure, it can form complexes with metal ions such as Pb2 and Mg2.

Use pH gradient extraction when there is a significant difference in acidity.

When there is no significant difference in acidity, use adsorption chromatography. The adsorbents include silica gel, calcium hydrogen phosphate (alumina is not used, especially basic alumina, to avoid chemical adsorption and difficulty in elution), petroleum ether, benzene, chloroform, etc. as washing agents. Remover.

Isolation of anthraquinone glycosides (1) Solvent method: Ethyl acetate, n-butanol → Separate anthraquinone glycosides from water-soluble impurities. (2) Chromatography Silica gel column chromatography, dextran gel column chromatography and reversed-phase silica gel column chromatography, etc.