Pyridine → 4-Methoxy cinnamic acid

Participants

Reaction Steps

17.4 g of D-panthenol )0.085 mol) are placed in 300 ml of methyl acetate while gassing with argon in a 750 ml 4-necked sulphonation flask provided with a thermometer, a 100 ml dropping funnel, a magnetic stirrer and a reflux condenser. A solution of 75.5 g of 4-methoxycinnamic acid chloride (0.38 mol) in 150 ml of methyl acetate is then added dropwise within about 20 minutes. A solution of 33.6 g of pyridine (0.425 mol) is added dropwise within about 40 minutes. The reaction mixture is finally heated to reflux temperature for 4 hours. After cooling the precipitate is filtered off under suction. The filtrate is washed with 2× 150 ml of 5% HCl and then with 2× 100 ml of water. After drying over Na2SO4 the organic phase is concentrated on a rotary evaporator. The yellow, viscous residue (74.2 g) is chromatographed (toluene/ethyl acetate, 7:1) on 1 kg of silica gel (0.040-0.063 mm) under 0.5 bar pressure. There are obtained 50.1 g of yellow <R>-panthenol triester of p-methoxycinnamic acid (yield 86%).

Provenance & Evidence