Compounds with or easily converted to unsaturated cyclic dione structures, as well as compounds closely related to quinones in biosynthesis

Quinones have an unsaturated ketone structure and are often colored when connected to auxochromophores (-OH, -OCH3, etc.); they often exist as pigments in animals, plants, and microorganisms

Benzoquinones

Naphthoquinones

Phenanthrenequinones

Anthraquinones

Existence status: • Benzoquinone and naphthoquinone: mostly exist in free state • Anthraquinones: often combined into glycosides and present in plants Sublimation: Free quinones are mostly sublimable Volatility: small molecule benzoquinone, naphthoquinone Fluorescence: conjugated chain: sky blue fluorescence, long conjugated chain: yellow fluorescence (anthraquinone)

Acidic

Color reaction

1. Organic solvent extraction method 2. Alkali extraction acid precipitation method: used to extract compounds containing acidic groups (Ar-OH, -COOH) 3. Steam distillation method: suitable for small molecule benzoquinone and naphthoquinone compounds

pH gradient extraction method

chromatography

Extraction: Plants often exist in the form of Mg2, K, Na, and Ca2. They should be fully acidified to free them.

Separation: big difference in polarity, extraction method

Use column chromatography for separation. Commonly used carriers: silica gel, polyamide, glucose gel (larger molecules come down first)

Examples: Rhubarb, Glucose Gel (MW) • Dianthrone glycosides • Anthraquinone diglucoside • Anthraquinone monoglycosides • Anthraquinone aglycone

Benzoquinone: ~240 nm: strong peak; ~285 nm: moderately strong peak; ~400 nm: weak peak

Naphthoquinones: 257nm, introducing auxochromophore to shift to red

Anthraquinones: Peak Ⅰ: around 230 nm (strong absorption peak of the mother core) Peak II: 240 ~ 260 nm (caused by benzene-like structure) Peak III: 262 ~ 295 nm (caused by quinone-like structure) Peak IV: 305 ~ 389 nm (caused by benzene-like structure) Peak V: > 400 nm (caused by >C=O in the quinone-like structure)

Hydroxyanthraquinones

The molecular ion peak is usually the base peak, and there are fragment ion peaks missing 1-2 molecules of CO.

When there is a power-supplying substituent on the quinone ring, the chemical displacement of other protons on the quinone ring shifts to a higher field.

methylation reaction

acetylation reaction

Activity pattern: glycoside>glycone, dianthrone>anthrol>anthraquinone (containing COOH>containing OH>OH substituted) The main laxative components in rhubarb are: dianthrones

Aglycon activity > glycoside; rhein, emodin, aloe-emodin, etc. have this effect

Rhein, emodin, etc. inhibit breast cancer and Ehrlich ascites cancer in rats

Significant inhibitory effect on cAMP phosphodiesterase