Ethyl bromoacetate → 4-Oxo-1,2,3,4-tetrahydronaphthalene-2-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

100 mL (0.425 mol) of diethyl benzylmalonate were added dropwise to a stirred suspension of 28 g (0.7 mol) of NaH (60% dispersion in mineral oil) in 550 mL of absolute ethanol at room temperature. The reaction mixture was refluxed 2 h, then cooled to 50° C. and 47.1 mL (0.425 mol) of ethyl bromoacetate were added dropwise. The reaction mixture was refluxed 2 h, then quenched with 150 mL of water; a solution of 140 g (3.5 mol) of NaOH in 400 mL of water was added and the mixture was heated to reflux for 1 h. EtOH was removed in vacuo, the aqueous solution was washed with Et2O and then carefully brought to acidic pH with 350 mL of 37% HCl and extracted with AcOEt. The solvent was removed in vacuo and the resulting residue was heated to 180° C. for 30 min. After cooling to room temperature, 100 mL of 95% H2SO4 were added and the reaction mixture stirred for 2 h, then it was poured onto 500 g of crushed ice and extracted with Et2O. The organic phase was dried and the solvent removed in vacuo. The resulting residue was taken up in Et2O, washed with 40% NaOH solution then brought to acidic pH with 37% HCl and extracted with Et2O. The organic phase was dried and the solvent removed in vacuo. The resulting solid residue was triturated with Et2O, filtered and dried yielding 15 g of the title compound, used without further purification. m.p.=146-147° C. IR (cm−1): 2924, 1692, 1600; NMR (300 MHz, DMSO, δ ppm): 12.6-12.5 (bs, 1H); 7.9 (d, 1H); 7.6-7.5 (m, 1H); 7.4-7.3 (m, 2H); 3.3-3.1 (m, 3H); 2.7 (m, 2H). MS (m/z): 191.1 (MH+).

Provenance & Evidence