Crystal Structure of 14-Deoxy-11,12-Didehydroandrographolide — A Diterpenoid

The crystal structure of 14-deoxy-11,12-didehydroandrographolide has been determined by X-ray structure analysis. The compound crystallizes in the trigonal space group P3₁ with cell parameters a = b 15.860(3), c = 6.437(2) Å. The structure has been solved by direct methods and refined to R = 0.048. The six-membered rings are trans-fused and both are in the chair conformation. The furan ring is planar with maximum deviation −0.011 (4) Å for C(14). Molecular are held together by hydrogen bonds.