Chlorodifluoromethane → 4-(Difluoromethoxy)-alpha-(1-methylethyl)benzeneacetic acid

Beteiligte Stoffe

Reaktionsschritte

To a stirred mixture of 2-(4-hydroxyphenyl)-3-methylbutyric acid (10.0 g; 0.0515 mol), dioxane (65 ml), sodium hydroxide (19.08 g, 18.56 g real; 0.464 mol), and water (30 ml) is bubbled chlorodifluoromethane (46 g; 0.532 mol) at 80° C. over a four-hour period. The reaction mixture is then poured into 250 ml of ice water, washed with ether, acidified with concentrated hydrochloric acid to pH 3, and extracted with 200 ml of ether. The ether extract is washed with 100 ml of water, dried with sodium sulfate, filtered, and evaporated to a white paste. A mixture of hexane and methylene chloride is added. The resulting mixture is filtered to remove the solid which is the starting material. The filtrate is evaporated to give 5.41 g of product as a clear brown oil. The product is at least 85% pure as calculated by NMR. NMR (CDCl3 -d5 pyridine): δ6.57 (t, J=74.3 Hz, 1 H); δ3.63 (s, imp.); δ3.25 (d, J=10 Hz, 1H); δ2.37 (m, 1H); δ1.19 (d, J=6.5 Hz, 3H); δ0.78 (d, J=6.5 Hz, 3H); δ13.82 (s, 1H).

Herkunft & Nachweise