3,5-Dimethylbenzoyl Chloride → 1-(3,5-Dimethylphenyl)ethan-1-one

Participants

Reaction Steps

145 g. (0.41 mole ) of tris (acetylacetonato) iron (III) is added to a solution of 2.247 kg. (≤13.32 moles) of crude Compound CXXII containing some residual toluene (from Step 1) in 4.0 l. of dry tetrahydrofuran (dried over 3 Å. molecular sieves) at 20°-25° C., the reaction mixture is cooled to -15° C. with stirring under nitrogen, a solution of 1.096 kg. (14.65 moles) of methylmagnesium chloride in tetrahydrofuran (2.9M.) is added over a 2.5 hour period at a rate such that the temperature of the reaction mixture does not exceed 0° C. with stirring under nitrogen, and the reaction mixture is stirred at -10°-0° C. for 2 hours under nitrogen and quenched by portionwise siphoning into a mixture of 3 l. of saturated ammonium chloride solution and 250 ml. of concentrated (12M.) hydrochloric acid precooled to 5° C. The reaction vessel is washed sequentially with 1 l. of saturated ammonium chloride solution and 1 l. of tetrahydrofuran, the washes are combined with the reaction mixture, and the organic phase is separated. The aqueous phase is washed with 1 l. of tetrahydrofuran, and the washing is combined with the organic phase. The combined organic solution is washed with 2 l. of saturated sodium chloride solution, dried over 2.0 kg. of anhydrous sodium sulfate and filtered. The filter pad is washed three times with 500 ml. portions of tetrahydrofuran, the washings are added to the filtrate, and the solvent is evaporated at reduced pressure and 45° C. The resulting red oil is fractionally vacuum distilled through a 15 cm. Vigreux column to yield the 98.74% pure product as a colorless oil (896 g.). B.p. 68°-69° C./0.65 mm. Hg. Also obtained is 232 g. of 86.8% pure product. B.p. 60°-68° C./0.65 mm. Hg. Total yield, Steps 1 and 2, 55%.

Provenance & Evidence