Synthesis
The general procedure for the synthesis of 1-(4-chlorophenyl)-1-cyclopropanecarboxylic acid from 1-(4-chlorophenyl)-1-cyclopropanecarbonitrile is as follows: 1-(4-chlorophenyl)-1-cyclopropanecarbonitrile (18 g) obtained in Example 1 was added to 20% sulfuric acid solution (184 mL). The temperature was slowly raised to reflux and the reaction was maintained for 10-12 hours. Upon completion of the reaction, the reaction mixture was extracted using ethyl acetate. Subsequently, the carboxylic acid product in the organic layer was transferred to 20% sodium hydroxide solution for extraction. The aqueous phase was acidified to pH 2-4 with concentrated hydrochloric acid and a white solid product was precipitated. The solid was collected by filtration and washed with distilled water. After drying, 1-(4-chlorophenyl)-1-cyclopropanecarboxylic acid was obtained in 90-95% yield, 99.4% purity by HPLC and 152-155°C melting point.
References
[1] Patent: WO2009/150660, 2009, A1. Location in patent: Page/Page column 16
[2] Patent: WO2016/178092, 2016, A2. Location in patent: Page/Page column 63; 64
[3] Patent: WO2017/64628, 2017, A1. Location in patent: Page/Page column 33; 34
[4] Chemische Berichte, 1979, vol. 112, p. 3914 - 3933
[5] Patent: US2009/312558, 2009, A1. Location in patent: Page/Page column 6
