Hydrochloric Acid → 1,3-Dicyclopropylpropane-1,3-dione

Participants

Reaction Conditions

Reaction Steps

Methylcyclopropanecarboxylate (20.2 ml, 286.3 mmol) was added to a stirred solution of 1-cyclopropylethanone (9 ml, 152.4 mmol) in dimethylsulfoxide (25 ml). Sodium methoxide powder (10.8 g, 200 mmol) was added, and the reaction was stirred at 55° C. for 8 hours. The mixture was cooled, diluted with toluene, neutralised with 6M hydrochloric acid, and then extracted with toluene. The combined extracts were washed with sodium carbonate, dried over magnesium sulphate and evaporated in vacuo to provide the title compound (14.9 g, 78%) as a mixture 2:1 enol:ketone forms. 1H NMR (CDCl3, 400 MHz): δ=0.79-0.87 (m, 4H), 0.98-1.01 (m, 4H), 1.46-1.51 (m, 2H-enol), 1.93-1.97 (m, 2H-keto), 3.70 (s, 2H-keto), 5.65 (s, 1H-enol); LRMS: APCl+: m/z 153 [MH+]; APCl− m/z 151 [M−H]−.

Provenance & Evidence