Related Experiment Video
Updated: Mar 6, 2026

Synthesis and Characterization of Functionalized Metal-organic Frameworks
Published on: September 5, 2014
Crystal structure of a photobiologically active brominated angular pyran-ocoumarin: bromo-hy-droxy-seselin
A K Bauri1, Sabine Foro2, A F M Mustafizur Rahman3
1Bio-Organic Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India.
Abstract:
The title compound, C14H13BrO3 [systematic name: rac-(9S,10R)-9-bromo-10-hy-droxy-8,8-dimethyl-9,10-di-hydro-2H,8H-pyrano[2,3-f]chromen-2-one], is a substituted pyran-ocoumarin, 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, mol-ecules are linked by pairs of O-H⋯O hydrogen bonds, forming inversion dimers with an R22(16) ring motif. The dimers stack along the a-axis direction and are linked by offset π-π inter-actions, forming columns [inter-centroid distance = 3.514 (4) Å].
Related Concept Videos
Formation of Halohydrin from Alkenes
Halogenation of Alkenes
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
Regioselectivity of Electrophilic Additions-Peroxide Effect
Newman Projections
The organic molecules rotate across the single bonds leading to numerous temporary three-dimensional structures of varying energy known as...
VSEPR Theory and the Basic Shapes
Structure of Benzene: Kekulé Model
He proposed that benzene has a cyclic structure of six carbon atoms attached to one hydrogen atom each, with three alternating pi bonds.

