Acetone → 2,2-dimethyl-4-oxo-4H-1,3-benzodioxine-6-carboxylic acid

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A suspension of 4-hydroxyisophtalic acid (Aldrich, 5.0 g, 27.5 mmol) in acetone (10 mL), TFA (30 mL) and TFAA (10 mL) was heated at 100° C. for 24 hrs. The reaction mixture was concentrated under reduced pressure. The residue was taken up with an aqueous solution of HCl (100 mL, 1N) and extracted with EtOAc (3×200 L); The combined organic layers were dried over MgSO4 and the solvents were removed under reduced: pressure. The crude compound was recrystallized in Et2O (50 mL) to give 4.67 g (77%) of the title compound as a beige powder. 1H NMR (DMSO-d6) δ: 8.37 (d J=1.9 Hz, 1H), 8.19 (dd, J=2.2 and 8.7 Hz, 1H), 7.23 (d, J=8.3 Hz, 1H), 1.72 (s, 6H). HPLC, Rt: 2.40 min (purity: 95.7%).

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