Hydrochloric Acid → (2E)-3-[1-Methyl-5-(2-thienyl)-1H-pyrazol-4-yl]-2-propenoic acid

Participants

Reaction Conditions

Reaction Steps

To a mixture of ethyl (2E)-3-[1-methyl-5-(2-thienyl)-1H-pyrazol-4-yl]acrylate (2.0 g) and methanol (20 ml) was added 2N aqueous sodium hydroxide solution (7.6 ml) and the mixture was stirred at 60° C. for 30 min. 1N Hydrochloric acid was poured into the reaction mixture, and the precipitated solids were collected by filtration, washed with water and dried with airflow to give (2E)-3-[1-methyl-5-(2-thienyl)-1H-pyrazol-4-yl]acrylic acid (1.69 g, 95%) as crystals. Recrystallization thereof from methanol-isopropyl ether gave colorless prism crystals. melting point: 210-212° C.

Provenance & Evidence