Lithium Hydroxide → 3-cyclopropyl-1H-pyrrole-2-carboxylic acid

To a suspension of the starting methyl 3-cyclopropyl-1-(phenylsulfonyl)-1H-pyrrole-2-carboxylate (0.9 g, 3 mmol) in tetrahydrofurane (4.6 mL) and water (2.3 mL) was added lithium hydroxide (0.29 g, 12 mmol) and this mixture was heated to 100° C. in a microwave vial during 4 hours. Next, the reaction mixture was poured into water (50 mL) and this aqueous phase was washed with diethyl ether (2×). Afterwards, the aqueous layer was acidified until pH=3 by adding solid phosphoric acid and extracted with ethyl acetate (3×). The organic solution was washed with water and brine, dried (Na2SO4) and concentrated in vacuum to give 370 mg of the title compound.