Crystal structure of a photobiologically active brominated angular pyran­ocoumarin: bromo-hy­droxy-seselin

The title compound, C(14)H(13)BrO(3) [systematic name: rac-(9S,10R)-9-bromo-10-hy­droxy-8,8-dimethyl-9,10-di­hydro-2H,8H-pyrano[2,3-f]chromen-2-one], is a substituted pyran­ocoumarin, obtained by bromination of seselin [8,8-dimethyl-2H,8H-pyrano[2,3-f]chromen-2-one], which was isolated from the Indian herb Trachyspermum stictocarpum (Aajmod). The pyrano ring has a distorted half-chair conformation and its mean plane is inclined to the coumarin mean plane by 1.6 (2)°. In the crystal, mol­ecules are linked by pairs of O—H⋯O hydrogen bonds, forming inversion dimers with an R (2) (2)(16) ring motif. The dimers stack along the a-axis direction and are linked by offset π–π inter­actions, forming columns [inter­centroid distance = 3.514 (4) Å].