Isopropanol → 1,3-Diphenylpentane-1,4-dione

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

1-Trimethylsilanyl-ethanone (1.15 mL; 8.02 mmol) followed by DBU (0.18 mL; 1.2 mmol) were added to a suspension of 3-ethyl-5-(2-hydroxyethyl)-4-methylthiazolium bromide (304 mg; 1.21 mmol) in dry THF (5 mL). The mixture was heated at 70° C. for 4 min, cooled near rt, then chalcone (833 mg; 4.00 mmol) and 2-propanol (1.22 mL; 15.9 mmol) were added. The reaction was degassed and reacted under nitrogen at 70° C. After 24 h, the reaction was concentrated on a rotary evaporator. Ethyl acetate (25 mL) was added and this washed with H2O (3×3 mL) and satd NaCl (2×3 mL). The organic portion was dried (MgSO4) and filtered through silica with an EtOAc wash. Crude product was adsorbed onto silica (2 g) then purified by MPLC (40 g of silica using a 0→20% EtOAc in hexanes gradient). Pure product was obtained as a clear, colorless viscous liquid (980 mg; 97%). 1H NMR (CDCl3) d 7.98-7.94 (m, 2H), 7.56 (m, 1H), 7.47-7.42 (m, 2H), 7.39-7.27 (m, 5H), 4.44 (dd, J=3.6, 10.0 Hz, 1H), 4.02 (dd, J=10.0, 18.0 Hz, 1H), 3.14 (dd, J=3.6, 18.0 Hz, 1H); GC-MS 252 ([M]+).

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