General procedure for the synthesis of 1-cyano-1-cyclopropanecarboxylic acid from methyl 1-cyanocyclopropanecarboxylate: KOH (13.78 g, 85%, 209 mmol) was dissolved in 80 mL of ethanol, and then this solution was added to a 100 mL ethanol solution of methyl 1-cyano-1-cyclopropanecarboxylate (25.64 g, 205 mmol), and the reaction was stirred for 1 hour. After completion of the reaction, the mixture was evaporated and concentrated, dissolved in 200 mL of water and the aqueous phase was washed with 30 mL of chloroform. Subsequently, the aqueous phase was acidified with hydrochloric acid to pH=1. 30 g of NaCl was added to the acidified mixture, followed by 6 extractions with 50 mL of chloroform. All organic layers were combined, dried with anhydrous MgSO4 and finally the solvent was evaporated under vacuum to afford the target product 1-cyano-1-cyclopropanecarboxylic acid (20.60 g, 90% yield). The product was characterized by 1H NMR (200 MHz, DMSO-d6): δ 1.73 (m, 4H), 11.08 (s, 1H).
