Boron trifluoride → 1-(5-Ethyl-2,4-dihydroxyphenyl)-2-(4-methoxyphenyl)ethanone

Participants

Reaction Conditions

Reaction Steps

4-Ethylbenzene-1,3-diol (17.5 g, 159 mmol) and 4-methoxyphenylacetic acid (26.4 g, 159 mmol) was heated with boron trifluoride dietherate solution (100.7 ml, 795 mmol) to 90° C. for 3 hours. The mixture was then cooled to 50° C. before it was added to a stirred solution of 10% aqueous sodium acetate (11). The resulting mixture was stirred at room temperature over night at room temperature. The resulting solid was filtered off dissolved in a minimum volume of methanol and pre-absorbed onto silica gel. For the initial purification the crude material was chromatographed, eluting with an increasingly polar mixture of methylene chloride/methanol (95/5 to 90/10). The fractions containing product were grouped into two groups, evaporated under vacuum to give a solid which was triturated with diethyl ether in a further purification step. The title compound was obtained in three portions of varying purity as an off white solid from combined purest fractions (10.78 g, 26.2%) the less pure fractions (7.56 g, 18.4%) and from the combined, evaporated mother liquors after renewed trituration with iso-hexane/diethylether to give the title product (6.32 g, 15.4%). 1H NMR Spectrum (purest solid): δH (300 MHz, CDCl3) 1.22 (3H t, J=7.5 Hz), 1.63 (1H, s), 2.57 (2H q, J=7.5 Hz), 3.79 (3H, s), 4.16 (2H d, J=3.0 Hz), 5.52 (1H, s), 6.30 (1H, s), 6.85-6.90 (2H, m), 7.16-7.21 (2H, m), 7.59 (1H, s), 12.51 (1H, s); Mass Spectrum: (M+H−) 258.20.

Provenance & Evidence