Hydrochloric Acid → Phenylacetic Acid

Participants

Reaction Steps

The crude tetrahydro-2H-pyran-2-yl 2-phenylacetate (5a) and 1,5-dibromopentane (1.474 g, 6.41 mmol) were dissolved in dry hexamethylphosphoric triamide (6 ml) and the mixture was cooled in an ice bath. To the cooled solution 60% suspension of NaH in mineral oil (0.507 g, 12.67 mmol) was added and the reaction mixture was stirred at ice bath temperature for 15 minutes and at room temperature for 5 hours. The reaction mixture was diluted with dioxane (20 ml) and water (15 ml), and the pH of the reaction medium was brought to pH 1 with conc. HCl (3 ml). The reaction mixture was stirred for 20 minutes and poured into ethyl acetate (75 ml). The organic layer was washed with a mixture of 2 N HCl and brine, 1:1 (2×50 ml), brine (50 ml), and dried (Na2SO4). The solvents were evaporated and the residue was chromatographed on silica gel (50 g) with benzene-ethyl acetate-acetic acid (9:1:0.1) as eluent to give a crude product. The product was re-chromatographed on silica gel (50 g) with petroleum ether-ethyl acetate-acetic acid (8:2:0.1) as eluent to give the title compound (0.414 g, 47% based on 4a) as a white solid. 1H NMR (CDCl3, HMDSO) δ: 1.04-2.01 (8H, m); 2.19-2.62 (2H, m); 7.09-7.55 (5H, m), 10.29 (1H, br s).

Provenance & Evidence