反应详情

A solution of diethyl (3-methoxy-4-nitrobenzyl)phosphonate (Compound 1G, 5 g, 15.5 mmol) in thionyl chloride (50 mL, 690 mmol) was treated with catalytic amount of DMF and heated to reflux under nitrogen for 6 h. The mixture was concentrated under reduced pressure and co-evaporated with dichloroethane (50 mL) to give crude (ethyl chloro[(3-methoxy-4-nitrophenyl) methyl]phosphinate). This material was taken up in DCM (20 mL) and added to a solution of 2-propanol (4 mL, 52 mmol) and DIPEA (6 mL, 34.5 mmol) in DCM (20 mL). The resulting mixture was stirred at rt for 24 hrs. The solvents were evaporated and the residue was purified by column chromatography (SiO2, 5% methanol in dichloromethane) to give 3 g of the desired product as a light-yellow oil. 1H NMR (400 MHz, CDCl3) δ 7.8 2(d, J=8.4 Hz, 1H), 7.1 (s, 1H), 6.92 (d, J=8.5 Hz, 1H), 4.6-4.4.75 (m, 1H), 4.05-4.08 (m, 2H), 3.93 (s, 3H), 3.18 (d, J=20 Hz, 2H), 1.18-1.25 (m, 9H).

1. temperatureheated
2. temperatureto reflux under nitrogen for 6 h
3. concentrationThe mixture was concentrated under reduced pressure and co-evaporated with dichloroethane (50 mL)