Hydrochloric Acid → 2,4-Nonanedione

Participants

Reaction Steps

To a stirred solution of methyl acetate 15 (27.8 ml; 25.9 g; 350 mmol) in diethyl ether (200 ml) NaH (60% w/w; 4.80 g; 200 mmol) was added and resulted slurry was brought to boiling. Then a solution of 2-heptanone 16 (24.4 ml; 20.0 g; 175 mmol) in diethyl ether (150 ml) was added dropwise over 3 h. Refluxing was maintained for next 5 h. Then 10% aqueous solution of HCl with crushed ice (ca. 100 ml) was added carefully and organic phase was separated. Water phase was extracted with diethyl ether (150 ml) and combined organic phases were washed with saturated aqueous solution of NaHCO3 (50 ml), dried over anhydrous MgSO4 and concentrated under reduced pressure. The residue was purified by distillation under reduced pressure to give 15.6 g (99.7 mmol; 64% yield) of 17. 1H NMR (500 MHz, CDCl3) δ 0.90 (3H, m), 1.31 (2H, m), 1.60 (2H, m), 2.05 (2.1H, s), 2.13 (0.3H, s), 2.17 (0.3H, s), 2.24 (0.3H, s), 2.26 (1.4H, t, J=7.5 Hz), 2.42 (0.15H, t, J=7.5 Hz), 2.50 (0.25H, t, J=7.4 Hz), 3.57 (0.25H, s), 5.49 (0.7H, s); 13C NMR (126 MHz, CDCl3) δ 14.0, 22.5, 22.6, 23.1, 25.0, 25.5, 30.9, 31.2, 31.5, 38.3, 43.8, 58.0, 69.1, 191.5, 194.4, 202.2, 204.3, 204.6; MS (EI) m/z 157 ([M+H]+, 52), 156 (M+, 9), 141 (8), 113 (17), 100 (45), 85 (100); exact mass calculated for C9H16O2 156.1150. found 156.1151.

Provenance & Evidence