Formaldehyde → Ethyl 2-phenylacrylate

Participants

Reaction Conditions

Reaction Steps

A solution of diethyl oxalate (75 g, 513 mmole) and ethyl phenylacetate (108 g, 658 mmol) in 300 mL of dry toluene was slowly charged with solid sodium ethoxide (33.3 g, 489 mmol). A mild exothermic reaction was observed and the reaction mixture turned orange. Precipitation of the salt started within 1 hour and the reaction was left at room temperature overnight. The salt was filtered and washed thoroughly with dry ether. The solid was suspended in 200 mL of ether then acidified to pH2 with 5% aqueous hydrochloric acid. The aqueous layer was separated followed by additional extraction with ether (2×50 mL). The combined etheral solution was successively washed with a saturated solution of sodium bicarbonate (50 mL), water (2×50mL) and brine (50 mL), dried over magnesium sulfate and evaporated in vacuum at room temperature (to prevent possible decarboxylation). The resulting yellow oil was charged with water (250 mL) and formaldehyde (81 mL, 37% aqueous solution, 1 mole) and then it was cooled to 0° C. The resulting mixture was charged, very slowly, with potassium carbonate (72 g, 521 mmol), over 30 minutes. The temperature in the reaction flask was not allowed to exceed 15° C. The reaction mixture was stirred at room temperature for an additional two hours. The aqueous solution was extracted with ether (2×50 mL) and the combined ethereal solution was washed with water (2× 50 mL) and brine (50 mL), dried over magnesium sulfate and evaporated. The resulting yellow oil was purified by Kugelrohr distillation (80°-85° C., 0.5 mmHg) to yield 82.3 g (91%). 300MHz 1H NMR (CDCl3)δ7.46-7.31 (m,5 H), 6.37 (d, J=1.17 Hz, 1H), 5.91 (d, J=1.17 Hz, 1H), 4.31 (q, J=7.15 Hz, 2 H), 1.35 (t, J=7.15 Hz, 3 H). IR (neat)2995, 1740, 1610, 1500, 1450, 1405, 1370, 1310, 1200 cm-1.

Provenance & Evidence