Pyridine → 4-Methoxy cinnamic acid

Participants

Reaction Steps

11.3 g of D-panthenol (0.055 mol) are placed in 100 ml of THF while gassing with argon in a 500 ml 4-necked sulphonation flask provided with a thermometer, a 100 ml dropping funnel, a magnetic stirrer and a reflux condenser. A solution of 27.8 g of 4-methoxycinnamic acid chloride (0.14 mol) in 100 ml of tetrahydrofuran is then added dropwise within about 15 minutes. A solution of 11.1 g of pyridine (0.14 mol) is now added dropwise within about 30 minutes and the mixture is stirred for a further 3 hours. The precipitate is filtered off under suction and the filtrate is concentrated on a rotary evaporator. The residue is dissolved in 300 ml of CH2Cl2. This solution is washed with 2× 60 ml of 5% HCl and then with 2× 60 ml of 5% NaHCO3. After drying (Na2SO4) the organic phase is concentrated on a rotary evaporator. The yellow, viscous residue (33.8 g) is chromatographed (toluene/ethyl acetate, 8:2) on 1 kg of silica gel (0.04-0.063 mm) under 0.5 bar pressure. There are obtained 15.9 g of yellowish <R>-panthenol diester of p-methoxycinnamic acid (yield 55%).

Provenance & Evidence