A compound with molecular formula C₁₀H₁₂O₂ showed a strong IR band at ~ 1720 cm^-1, a peek at m/z 122 in the mass spectrum and the following ¹H NMR signals: δ 8.1- 8.0 (2H, m), 7.6-7.5 (1H, m), 7.5-7.3 (2H, m), 4.3 (2H, t), 1.8 (2H, sextet) and 1.0 (3H, t). The structure of the compound is: