Hydrochloric Acid → (2E)-3-(4-Bromo-2-thienyl)-2-propenoic acid

Participants

Reaction Conditions

Reaction Steps

Malonic acid (16.2 g) was added to a solution of 4-bromothiophen-2-aldehyde (25.1 g) in pyridine (100 cm3) and piperidine (3.2 cm3) and the resulting mixture was heated at 100° C. for 6.5 hours, allowed to cool to room temperature overnight and was then evaporated down to give a beige semi-solid. The semi-solid was treated with aqueous potassium hydroxide solution and the resulting mixture was diluted with water (50 cm3), acidified with concentrated hydrochloric acid (90 cm3) and then cooled to yield a precipitate which was filtered off, washed with ether/40-60 petrol and was then sucked dry (26.1 g) m.p. 167°-169° C. (aqueous methanol) Analysis; Calculated; C, 36.05; H, 2.15; Found; C, 36.30; H, 2.03.

Provenance & Evidence