Hydrochloric Acid → 2,2-Dimethyl-1-(4-methylphenyl)-1-propanone

To a suspension of 28.5 g (1.17 g. atoms) magnesium turnings in 150 ml tetrahydrofuran under a nitrogen atmosphere there is added 10 ml (1.17 mole) of 4-bromotoluene in 650 ml dry tetrahydrofuran, the reaction is started and the remainder of the bromotoluene solution is added dropwise at a rate that maintains a moderate reflux. After the addition is complete, the mixture is refluxed for an additional 1 1/2 hours. The resulting Grignard solution is added dropwise to a cold solution of 128.0 g. pivaloyl chloride (1.06 mole) in 500 ml dry tetrahydrofuran at a rate that maintains the temperature at 0° to -5° C. The solution is stirred for an additional 1 1/2 hours at 0° and then at room temperature for 18 hours. The mixture is then cooled to 0° and hydrolyzed by the addition of 100 ml 2N hydrochloric acid. The layers are separated and 200 ml of ether is added to the organic phases which is then washed respectively with 100 ml 2N hydrochloric acid, 100 ml. 10% sodium bicarbonate solution and 100 ml saturated sodium chloride. The resulting layer is dried over anhydrous sodium sulfate, filtered, and the solvent is removed in vacuo to give p-pivaloyl toluene (b.p. 80°-84° C/0.7 mm,n21 =1.5108). A mixture of 156.3 g. (0.886 mole) of the resulting p-pivaloyl toluene is then added to 157.8 g. (0.886) mole) N-bromosuccinimide, 4.0 g (0.016 mole) benzoyl peroxide and 150 ml. carbon tetrachloride and heated at reflux for 18 hours. The mixture is cooled and filtered and the resulting precipitate is washed with carbon tetrachloride. The solvents are removed in vacuo and the resulting oil is distilled in vacuo to give α-bromo-p-pivaloyl toluene (b.p. 124° - 132°/0.7 mm, n22 =1.5546-V.P.C. 96% monobromo 4%-dibromo).

1. additionAfter the addition
2. temperaturethe mixture is refluxed for an additional 1 1/2 hours
3. additionThe resulting Grignard solution is added dropwise to a cold solution of 128.0 g
4. customat 0° to -5° C
5. waitat room temperature for 18 hours
6. customThe layers are separated
7. addition200 ml of ether is added to the organic phases which
8. washis then washed respectively with 100 ml 2N hydrochloric acid, 100 ml
9. dry with materialThe resulting layer is dried over anhydrous sodium sulfate
10. filtrationfiltered
11. customthe solvent is removed in vacuo

ORD record

ord-496eb6b1c86b4d97841b175324357537

Source dataset

uspto-grants-1976_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US03996286