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

Lysergic 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.