Technical note: N-Isopropylbutylone unveiled – Differentiating the new synthetic cathinone in ecstasy from its close analogues with GC-MS and NMR spectroscopy

Abstract

N-Isopropylbutylone, a novel synthetic cathinone, was identified in an ecstasy tablet bearing a "SUPERMAN" logo imprint, alongside methamphetamine and ketamine. The laboratory employed two orthogonal analytical techniques – gas chromatography with electron ionisation mass spectrometry (GC-EI-MS) and nuclear magnetic resonance (NMR) spectroscopy to determine the identity of the novel drug present. The identification of N-isopropylbutylone was challenging due to its mass spectral similarities with structural isomers, particularly N-propylbutylone. Multiple NMR experiments such as correlation spectroscopy (COSY), distortionless enhancement by polarisation transfer (DEPT), heteronuclear multiple quantum coherence (HMQC), and heteronuclear multiple bond correlation (HMBC) were utilised to unequivocally confirm the structure. The findings highlight the importance of orthogonal analytical techniques in identifying new psychoactive substances and underscore the ongoing challenges in forensic drug analysis.