Purify 2-chloroskatole by chromatography on silica gel in CH2Cl2/pet ether (1:2), followed by recrystallisation from aqueous EtOH, aqueous AcOH or pet ether (m 113.5o). The picrate has m 121-122o(dec) (orange-red crystals from pet ether). [Phillips & Cohen J Am Chem Soc 108 2023 1986, Beilstein 20 H 317, 20 III/IV 3212.]
