title: Structure elucidation of a new open chain isomer of the cannabimimetic cyclopropoylindole A-796,260.
abstract: A new hitherto unknown ring opened isomer of the tetramethylcyclopropoylindole 1-(2-morpholin-4-ylethyl)-1H-indol-3-yl]-(2,2,3,3-tetramethylcyclopropyl)methanone (A-796,260) has been identified in a seizure of the German Customs. It bears an E-alkene moiety in the side chain with a tert.-butyl group, having a 3-penten-5-one skeleton. The isomer is not identical to the known products of thermal ring opening of tetramethylcyclopropoylindoles, which have a 1-pentene-5-one alkyl chain, instead. We postulate its formation via a Wagner-Meerwein-rearrangement under acidic conditions during the attempted synthesis of the desired tetramethylcyclopropoylindole. Whether the compound, found in high purity, has been the result of a synthesis fault or has been synthesized intentionally and if the new isomer has cannabimimetic potential, is still unknown. During structure elucidation with NMR spectroscopy and mass spectrometry, interesting phenomena have been detected concerning the product ion spectrometry of tetramethylcyclopropoylindoles.
authors.affiliation: State Bureau of Criminal Investigation Schleswig-Holstein, Section Narcotics/Toxicology, Mühlenweg 166, D-24116 Kiel, Germany. Electronic address: Dr.-Folker.Westphal@polizei.landsh.de.
authors.forename: Folker
authors.initials: F
authors.lastname: Westphal
authors.affiliation: Pharmaceutical Institute, Department of Pharmaceutical/Medicinal Chemistry, Christian-Albrechts-University Kiel, Gutenbergstr. 76, 24118 Kiel, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Girreser
authors.affiliation: Centre for Education and Science of the Federal Finance Administration, Laboratory Frankfurt, Gutleutstr. 185, 60327 Frankfurt a.M., Germany.
authors.forename: Siegfried
authors.initials: S
authors.lastname: Knecht
keywords: GC–MS; IR; NMR; New ring opened isomer of A-796,260; Product ion spectrometry of cyclopropoylindoles; Structure elucidation