Step 1: Synthesis of 2-phenoxyethanol
Add 200 ml of anhydrous ethanol to a 10000 m L three-necked round-bottomed flask, dissolve sodium metal (23 g) in it, then add phenol (94 g, 900 mL), 2-chloroethanol (700 mL) , respectively, and heat and reflux until the reaction mixture is neutral. The reaction was tracked by running a plate during the reaction (unfolding agent: chloroform:methanol:benzene=200:1:1 ; Rf=0.3). Ethanol was removed by distillation under reduced pressure with a rotary evaporator, and 500 mL of distilled water was added. It was then extracted with ether three times (about 400 mL each time) and washed several times with dilute sodium hydroxide solution and distilled water respectively (to remove phenol). The ether was then removed by distillation at atmospheric pressure, and the residue was distilled under reduced pressure to collect a fraction of 163-166°C (18 mmHg) was obtained. The ether is a colorless thick liquid, bp : 240-246°C, refractive index: 1.532, d:1.1002, insoluble in water but soluble in ether and alcohol (yield: 75 %).
Step 2: Synthesis of 2,3-dihydrobenzofuran
To a 250 mL three-necked round-bottomed flask, 2-phenoxyethanol (50 g) and zinc chloride (5 g) were added and heated to 225°C reflux with mixing and stirring, then slowly reduced to 190C reflux. The reaction was carried out over 5h with a running plate to follow the reaction (unfolding agent:chloroform:methanol:benzene=20:1:1 ; Rf=0.6). Cooling, distillation under reduced pressure and collection of (88-90)°C ( 18 mmHg) fraction gave the title compound. The compound was a colorless liquid, b p : 188-189C, refractive index: 1.549, d 1.053 , yield: (70%).
