| Abstract: | A refined crystal structure of andrographolide has been obtained by X-ray anaysis using CuKα radiation. It crystallizes in the monoclinic crystal system with unique b-axis in space group P21. The unit cell parameters are a = 6.552(2) Å, b = 8.009(1) Å, c = 17.989(1) Å and interaxial angle β = 97.32(1)°. The structure has been solved by direct methods and was refined up to R = 0.041, ωR = 0.0464. Both the cyclohexane rings are in chair conformation with the furan ring in twist conformation. The crystal structure is stabilized by hydrogen bonding. |
