New materials used for the synthesis of 2‐chlorophenyl cyclopentyl ketone seized from an illicit ketamine manufacturing unit

Ketamine deemed as a psychoactive substance has gained popularity for recreational use owing to its hallucinogenic and dissociative effects. Understanding the synthetic processes of ketamine can provide essential clues for law enforcement officers against illicit ketamine manufacturing. In this case report, a chemical company was being monitored by law enforcement officers due to its importation of precursors and materials that could be used for the synthesis of illicit drugs. After materials and products seized from this chemical company were employed for analyses using gas chromatography–mass spectrometry, liquid chromatography–high‐resolution mass spectrometry, and nuclear magnetic resonance analyses, ketamine, hydroxylamine, 2‐chlorophenyl cyclopentyl ketone, and cyclopentanone p‐toluenesulfonylhydrazone were identified. In addition, a novel process for the synthesis of ketamine precursor 2‐chlorophenyl cyclopentyl ketone from cyclopentanone p‐toluenesulfonylhydrazone and 2‐chlorobenzaldehyde was validated. This is the first report to uncover this novel process for the synthesis of 2‐chlorophenyl cyclopentyl ketone and can be used to increase awareness among law enforcement officers and forensic practitioners about these novel starting materials for the synthesis of ketamine.