Structural analysis of an lysergic acid diethylamide (LSD) analogue N‐methyl‐N‐isopropyllysergamide (MiPLA): Insights from Rotamers in NMR spectra

Abstract

AbstractLysergic acid diethylamide (LSD) is a hallucinogenic compound that binds to and activates the serotonin 2A receptor and is classified as a controlled narcotic in Japan. Recently, MiPLA, an N‐methyl‐N‐isopropyl derivative of LSD, has been detected in paper‐sheet products in several countries. This study focuses on the synthesis of MiPLA and includes a comprehensive analysis involving structural and liquid chromatography–mass spectrometry (LC‐MS). Particularly, MiPLA was synthesized in three‐steps starting from ergometrine maleate, which resulted in the formation of (8S)‐isomer, iso‐MiPLA, as a by‐product. The LC‐MS results showed that LSD, MiPLA, and iso‐MiPLA exhibited different retention times. Their chemical structures were determined using nuclear magnetic resonance spectroscopy, which revealed the presence of rotamers involving the N‐methyl‐N‐isopropyl groups of tertiary amides in MiPLA and iso‐MiPLA.