Hydrochloric Acid → 612070-27-6

Participants

Reaction Steps

In a dry 250 ml three necked flask was placed magnesium turnings (2.46 g, 101.2 mmol), 5 ml dry THF and two drops of 1,2-dibromoethane, stirred under N2 at room temperature. Subsequently 1,4-dibromobenzene (19.8 g, 84 mmol) in 15 ml dry THF was added dropwise over 30 min. An ice water bath was occasionally used to moderate the reaction. After addition was complete the reaction was stirred for 2 hrs to complete conversion of bromobenzene. A solution of 2-methyl-2-trimethylsilanyloxy-1-propionitrile (13.25 g, 85 mmol) in 15 ml dry THF was added dropwise to the Grignard reagent and the mixture was stirred for 20 hrs. By this time a large quantity of white precipitate was formed. The intermediate produced was hydrolyzed by cautious addition of 80 ml 6N HCl with ice cooling and vigorous stirring as the solution warmed to room temperature and then kept stirring at this temperature for 4 hrs. Solid sodium bicarbonate was added cautiously to neutralize the excess acid and the solid in the mixture was removed by vacuum filtration through a pad of Celite and the Celite pad was washed three more times with ethyl acetate. The filtrate was extracted three times with ethyl acetate, dried over anhydrous MgSO4. The solvent was removed by rotary evaporation and the product obtained as liquid, which was suitable for direct use in the next step. For further characterization one gram of the crude product was purified by silica gel column chromatography using EtOAc/hexane 1/4 as eluent. Calculated yield: (77%). 1H NMR (400 MHz, CDCl3) δ 7.88 (d, J=8.4 Hz, 2H), 7.49 (d, J=8.4 Hz, 2H), 4.01 (s, 1H), 1.51 (s, 6H). 13C NMR (100 MHz, (100 MHz, CDCl3) δ 203.21, 134.46, 132.63, 131.28, 127.68, 76.66, 28.11.

Provenance & Evidence