反应详情

To a solution of 3,5-dimethyl-4-hydroxy-benzonitrile (5.0 g, 34.0 mmol) in THF (40 mL), rac-(2,2-dimethyl-[1,3]dioxolan-4-yl)-methanol (4.49 g, 34.0 mmol) followed by triphenylphosphine (13.4 g, 50.9 mmol) is added. The mixture is cooled with an ice-bath before DEAD (8.87 g, 50.9 mmol, 23.4 mL of a 40% solution in toluene) is added dropwise. The mixture is stirred at rt for 1 h, the solvent is removed in vacuo and the residue is purified by CC on silica gel eluting with heptane:EA 99:1 to 92:8 to give rac-4-(2,2-dimethyl-[1,3]dioxolan-4-ylmethoxy)-3,5-dimethyl-benzonitrile (7.20 g) as a pale yellow oil; LC-MS: tR=0.99 min, [M+1]+=not detected. b) To a solution of potassium tert.-butylate (6.18 g, 55.1 mmol) in methanol (125 mL), hydroxylamine hydrochloride (5.74 g, 82.7 mmol) is added. To this solution, a solution of rac-4-(2,2-dimethyl-[1,3]dioxolan-4-ylmethoxy)-3,5-dimethyl-benzonitrile (7.20 g, 27.6 mmol) in methanol (40 mL) is added. The mixture is refluxed for 72 h before the solvent is removed in vacuo. The residue is purified by prep. HPLC (XBridge Prep C18, 30×75 mm, 5 μm, 2-95% acetonitrile in water containing 0.5% sat. aq. NH3) to give the title compound (4.85 g) as a pale yellow solid; LC-MS: tR=0.67 min, [M+1]+=295.06; 1H NMR (CDCl3): δ1.43 (s, 3H), 1.48 (s, 3H), 2.29 (s, 6H), 3.76-3.81 (m, 1H), 3.83-3.88 (m, 1H), 3.93-3.99 (m, 1H), 4.17-4.23 (m, 1H), 4.47-4.54 (m, 1H), 5.02 (s br, 1H), 7.28 (s, 2H).

1. temperatureThe mixture is refluxed for 72 h before the solvent
2. customis removed in vacuo
3. customThe residue is purified by prep