Patent ID: 11912717
Assignee: SHENZHEN TENVER BIOPHARM CO., LTD.
Field: Organic fine chemistry (Chemistry)
Classification: CPC C  A | IPC A  C

Claim 3:
4. A method for preparing the crystal form I of tenvermectin B according to claim 1, wherein the method comprises a step of precipitating the crystal form I of tenvermectin B from a solvent system containing formamide;
wherein the solvent system containing formamide is a combination of ethanol, formamide and water or a combination of acetone, formamide and water;
the method comprises steps of: dissolving tenvermectin B with ethanol or acetone, then adding formamide and water in sequence, stirring and crystallizing the thus obtained mixture to obtain the crystal form I of tenvermectin B;
wherein a ratio of the mass of the tenvermectin B to the volume of ethanol or acetone to the volume of formamide to the volume of water is 1 g:2 ml:4-5 ml:2 ml.