Related Experiment Video
Updated: Apr 11, 2026

Syntheses, Crystallization, and Spectroscopic Characterization of 3,5-Lutidine N-Oxide Dehydrate
Published on: April 24, 2018
Crystal structure of 7-[(2E)-2-benzyl-idene-3-oxobut-oxy]-4-methyl-2H-chromen-2-one
Ignez Caracelli1, Julio Zukerman-Schpector2, Paulo J S Moran3
1Departmento de Física, Universidade Federal de São Carlos, 13565-905 São Carlos, SP , Brazil.
Abstract:
Two independent mol-ecules (A and B) comprise the asymmetric unit of the title compound, C21H18O4. There are significant conformational differences between the mol-ecules relating in particular to the relative orientation of the 3-oxo-2-(phenyl-methyl-idene)but-oxy substituent with respect to the superimposable chromen-2-one residues. To a first approximation, the substituents are mirror images; both are approximately perpendicular to the chromen-2-one fused ring system with dihedral angles of 88.50 (7) (A) and 81.96 (7)° (B). Another difference between the independent mol-ecules is noted in the dihedral angles between the adjacent phenyl and but-3-en-2-one groups of 8.72 (12) (A) and 27.70 (10)° (B). The conformation about the ethene bond in both mol-ecules is E. The crystal packing features C-H⋯O, C-H⋯π(ar-yl) and π-π [Cg⋯Cg = 3.6657 (8) and 3.7778 (8) Å] stacking inter-actions, which generate a three-dimensional network.
Related Concept Videos
Structure of Benzene: Molecular Orbital Model
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.
Prochirality
Aromatic Hydrocarbon Cations: Structural Overview
Removing one hydrogen from the intervening CH2 group...
Stereoisomerism of Cyclic Compounds
Benzene to 1,4-Cyclohexadiene: Birch Reduction Mechanism
![Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F60786.jpg&w=3840&q=50)
