Ammonium Chloride → HCID 19095326, compound

Participants

Reaction Steps

2-(2-Bromoethyl)-1,3-dioxolane (38 ml) was added dropwise within 15 minutes under argon and while stirring at a maximum 30° C. to a suspension of Rieke magnesium, prepared from 43.5 g of magnesium chloride, in 1300 ml of absolute tetrahydrofuran. The suspension was stirred at room temperature for 30 minutes, cooled to 0° C. and, after the addition of 42.2 g of copper(I) bromide, stirred at 0° C. for 15 minutes. After cooling to -70° C. 50.0 g of 3,4-dimethoxybenzoyl chloride in 200 ml of absolute tetrahydrofuran were added dropwise within 20 minutes. The reaction mixture was stirred at -70° C. for 30 minutes and at room temperature for 2 hours and subsequently hydrolyzed with 1000 ml of saturated ammonium chloride solution while cooling at a maximum 20° C. After the addition of 500 ml of water the mixture was extracted three times with ethyl acetate (1×1000 ml, 2×500 ml). The combined organic extracts were washed with 1000 ml of saturated sodium chloride solution, dried over MgSO4 and freed from solvent. The residue, 69.5 g of dark brown oil, was chromatographed on 1000 g of silica gel with ethyl acetate/hexane (1:1) as the eluent. There were obtained 26.5 g of crude product which were dissolved in a 12-fold amount of n-hexane with the addition of 100 ml of methylene chloride. 50 ml of methylene chloride were distilled off. 22.3 g (34%) of 3-(1,3-dioxolan-2-yl)-3',4'-dimethoxypropiophenone were isolated as colourless crystals which melted at 103°-105° C.

Provenance & Evidence