Quantum-chemical, NMR and X-ray diffraction studies on (+/-)-1-[3,4-(methylenedioxy)phenyl]-2-methylaminopropane

Zapata-Torres, G; CASSELS, BK; Parra-Mouchet, J; Mascarenhas, YP; Ellena, J.; De Araujo, AS

Abstract

Time-averaged conformations of (±)-1-[3,4-(methylenedioxy)phenyl]-2-methylaminopropane hydrochloride (MDMA, "ecstasy") in D 2O, and of its free base and trifluoroacetate in CDCl 3, were deduced from their 1H NMR spectra and used to calculate their conformer distribution. Their rotational potential energy surface (PES) was calculated at the RHF/6-31G(d,p), B3LYP/6-31G(d,p), B3LYP/cc-pVDZ and AM1 levels. Solvent effects were evaluated using the polarizable continuum model. The NMR and theoretical studies showed that, in the free base, the N-methyl group and the ring are preferentially trans. This preference is stronger in the salts and corresponds to the X-ray structure of the hydrochloride. However, the energy barriers separating these forms are very low. The X-ray diffraction crystal structures of the anhydrous salt and its monohydrate differed mainly in the trans or cis relationship of the N-methyl group to the α-methyl, although these two forms interconvert freely in solution. © 2007 Elsevier Inc. All rights reserved.

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Título según WOS: Quantum-chemical, NMR and X-ray diffraction studies on (+/-)-1-[3,4-(methylenedioxy)phenyl]-2-methylaminopropane
Título según SCOPUS: Quantum-chemical, NMR and X-ray diffraction studies on (±)-1-[3,4-(methylenedioxy)phenyl]-2-methylaminopropane
Título de la Revista: JOURNAL OF MOLECULAR GRAPHICS & MODELLING
Volumen: 26
Número: 8
Editorial: Elsevier Science Inc.
Fecha de publicación: 2008
Página de inicio: 1296
Página final: 1305
Idioma: English
DOI:

10.1016/j.jmgm.2007.12.004

Notas: ISI, SCOPUS