反应详情

A solution of 13.1 g (120.8 mmol, 2.8 equiv) of benzyl alcohol in 35 ml of dry tetrahydrofuran is added dropwise over 10 minutes to a room temperature slurry of 4.3 g (107.5 mmol, 2.5 equiv) of 60% NaH oil dispersion in 65 ml of tetrahydrofuran under nitrogen atmosphere. The reaction is stirred for 15 minutes then cooled in an ice-water bath. A hot solution of 11.4 g (43.7 mmol) 3-chloro-5-methoxybenzo[b]thiophene-2-carbonylchloride (prepared by the method described by Sudabeh Pakray and Raymond N. Castle in J. Heterocyclic Chem., 1986, 23, 1571) in 95 ml of tetrahydrofuran is added rapidly to the 0° C. reaction mixture. The reaction is stirred at 0° C. for 15 minutes, warmed at reflux for three hours and allowed to cool to room temperature before pouring onto 700 g of ice-water. The resulting mixture is extracted with diethyl ether (4×200 ml). The combined extracts are washed with saturated aqueous NaHCO3 (100 ml), water (100 ml) and saturated aqueous NaCl, dried over Na2SO4 and concentrated in vacuo to give a brownish yellow solid. The material was used as is in the subsequent reaction. A sample of the residue is rccrystallized from ethanol-water to give analytically pure benzyl 3-benzyloxy-5-methoxybenzo[b]thiophene-2-carboxylate as a white crystalline solid: mp 66°-67° C.

1. temperaturethen cooled in an ice-water bath
2. stirringThe reaction is stirred at 0° C. for 15 minutes
3. temperaturewarmed
4. temperatureat reflux for three hours
5. extractionThe resulting mixture is extracted with diethyl ether (4×200 ml)
6. washThe combined extracts are washed with saturated aqueous NaHCO3 (100 ml), water (100 ml) and saturated aqueous NaCl
7. dry with materialdried over Na2SO4
8. concentrationconcentrated in vacuo
9. customto give a brownish yellow solid
10. customas is in the subsequent reaction