Puerarin monocrystal and preparation method thereof

Abstract

The invention relates to a puerarin monocrystal and a preparation method thereof. The puerarin monocrystal is named crystal form A, the CCDC number is 708830, the crystal structure is asymmetrical, each crystal cell contains two asymmetrical molecules, i.e. molecule a and molecule b, each of which carries a molecular crystal water, and moreover, the binding sites of the crystal waters are different. The crystal water of the molecule a and a hydroxyl group on a benzene ring carry out hydrogen bonding, the crystal water of the molecule b and a carbonyl group on a flavone mother nucleus carry out hydrogen bonding, the hydroxymethyl group of the glucose of the molecule a is at the position of an equatorial bond and perpendicular to a ring plane, the oxygen atom of the hydroxymethyl group is in a saccharide ring plane, the hydroxymethyl group of the glucose of the molecule b is at the position of an axial bond and perpendicular to a ring plane, the hydrogen on the rest pyranose carboatomic ring is an axial bond, the hydroxyl group is positioned at an equatorial bond, and the molecular formulas of the molecule a and the molecule b are the same, i.e. C21H20O9.H2O. The absolute configuration of the puerarin monocrystal is an asymmetrical isomer. The melting point of the puerarin monocrystal is increased, and the heat stability is remarkably enhanced compared with powder. The average purity of the puerarin crystal form A reaches 99.8 percent, higher than 99.1 percent of average purity of bulk pharmaceutical chemicals, and the quality is remarkably increased.

Description

technical field [0001] The invention relates to a new crystal form of puerarin single crystal and a preparation method thereof. Background technique [0002] The molecular structure of puerarin is shown in the figure below. It is soluble in methanol, slightly soluble in ethanol, slightly soluble in water (0.462g / 100ml), and insoluble in chloroform or ether. The aqueous solution is clear and colorless, with a pH value of 3.5-5.5. [0003] [0004] The important structural difference of puerarin from other puerarin flavonoids is that puerarin is a carbon-carbon glycoside, while most other puerarin flavonoid glycosides are carbon-oxygen glycosides. The method of recrystallization with glacial acetic acid is often used for final refining of puerarin. However, glacial acetic acid is expensive in industrial production and pollutes the environment. [0005] Patent application 200410014458.9 "Method for Crystallization and Purification of High-Purity Puerarin" placed the super...

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Problems solved by technology

[0007] So far, there is no report on the method and crystal structure data of puerarin single crystal

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