(E)-2-Acetylcinnamic Acid: Hydrogen-Bonding Pattern of an α,β-Unsaturated β'-Keto Acid

The title compound, (E)-2-acetyl-3-phenylpropenoic acid, C₁₁H₁₀O₃, adopts a conformation incorporating a planar trans-cinnamic acid, with the α-acetyl group rotated orthogonal to it. Pairs of mol­ecules of identical conformational chirality form carboxyl dimers across C₂ axes, and the acid group displays disorder. There is a 2.64 Å ketone-O...methyl-H close contact between centrosymmetrically related dimer units.

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