Resolution and chiroptical properties of the neurotoxin 1-trichloromethyl-1,2,3,4-tetrahydro-β-carboline (TaClo) and related compounds: quantum chemical CD calculations and X-ray diffraction analysis

• Published in: Tetrahedron Vol. 60; no. 37; pp. 8143 - 8151
• Main Authors: Bringmann, Gerhard, Feineis, Doris, God, Ralf, Maksimenka, Katja, Mühlbacher, Jörg, Messer, Kim, Münchbach, Miriam, Gulden, Klaus-Peter, Peters, Eva-Maria, Peters, Karl
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 06.09.2004
• Subjects: 1-Trichloromethyl-1,2,3,4-tetrahydro-β-carboline (TaClo); Absolute configuration; Chloral-derived tetrahydro-β-carbolines; Circular dichroism; Crystal structures; Enantiomeric resolution; LC-CD coupling; Quantum chemical CD calculations; Chloral-derived tetrahydro-β-carbolines; Enantiomeric resolution; Crystal structures; LC-CD coupling; Absolute configuration; 1-Trichloromethyl-1,2,3,4-tetrahydro-β-carboline (TaClo); Quantum chemical CD calculations; Circular dichroism
• ISSN: 0040-4020; 1464-5416
• DOI: 10.1016/j.tet.2004.06.093

Separation and stereochemical attribution of the two enantiomers of the neurotoxin 1-trichloromethyl-1,2,3,4-tetrahydro-β-carboline (TaClo) has been achieved by applying chromatography on a chiral phase HPLC column in hyphenation with circular dichroism (CD) spectroscopy (LC-CD coupling). Assignment of the absolute configuration of TaClo and its N-methyl analog has been achieved by quantum chemical CD calculations and has finally been confirmed by single-crystal X-ray diffraction analyses of the two enantiomers of N-formyl-TaClo as obtained in enantiomerically pure form by crystallization. Assignment of the absolute configuration of the two TaClo enantiomers, ( S)-TaClo [ ( S)- 3 ] and ( R)-TaClo [ ( R)- 3 ] was achieved by CD spectroscopy and confirmed by X-ray crystallography.