Sodium Hydroxide → 1-[Methyl-(4-fluorophenyl)sulfonyl-amino]cyclopropanecarboxylic acid

A solution of 14A (1.3 g, 4.52 mmol) in dioxane (40 mL) was added with 10% NaOH aq. solution (20 mL) and the mixture was heated at 50° C. overnight. The organic solvent was removed under reduced pressure and the aqueous phase was acidified with 10% HCl. The solid formed was collected by filtration, washed with water (2×20 mL) and dried to afford 15A as white solid (1.0 g, 81% yield). 1HNMR (DMSO, 200 MHz) δ 1.40 (bs, 4H), 2.91 (s, 3H), 7.42 (m, 2H), 7.80 (m, 2H), 12.60 (bs, 1H).