Research Article

Surprisingly Difficult Resolution of N-Methylated Cationic [4]Helicenes

Nathalie Mehanna,
Stéphane Grass,
Jérôme Lacour^*

Article first published online: 8 MAY 2012

DOI: 10.1002/chir.22032

Issue

Chirality

Special Issue: Proceedings from the 23rd International Symposium on Chirality, Liverpool, UK, 2011

Volume 24, Issue 11, pages 928–935, November 2012

Additional Information

How to Cite

Mehanna N., Grass S. and Lacour J. (2012), Surprisingly Difficult Resolution of N-Methylated Cationic [4]Helicenes, Chirality. DOI: 10.1002/chir.22032

Author Information

Department of Organic Chemistry, University of Geneva, Geneva, Switzerland

^*Jérôme Lacour, Department of Organic Chemistry, University of Geneva, Quai Ernest Ansermet 30, CH-1211 Geneva 4, Switzerland. E-mail: jerome.lacour@unige.ch

Publication History

Issue published online: 23 OCT 2012
Article first published online: 8 MAY 2012
Manuscript Accepted: 24 JAN 2012
Manuscript Received: 16 SEP 2011

Funded by

Swiss National Science Foundation. Grant Number: FNS-20020_135072

ARTICLE TOOLS

View Full Article with Supporting Information (HTML) Get PDF (800K)

Chemistry Terms

Choose one or more boxes to highlight terms.

Chemical Names
Reagents & Catalysts
Drug Synonyms
Reaction Types
Chemical Technology

Keywords:

chromatography;
helicene;
resolution;
side chain effect;
sulfoxide

ABSTRACT

1,13-Dimethoxyquinacridinium ions of type 3 are highly configurationally stable [4]helicenes that can be synthesized in racemic form in a single step from tris(2,6-dimethoxyphenyl)methylium ion. Previously, it had been shown that the single enantiomers can be routinely obtained from racemic mixtures through Pummerer fragmentations of diastereomerically pure sulfoxide adducts that release the enantiopure cations after a C–C bond rupture. This resolution protocol is readily performed because of a (normally) large retention difference of the diastereomers over silica gel. Herein, we report that it is not always the case. Introduction of N-methyl side chain(s) at the periphery of the helical quinacridinium cations, which are needed for photophysical and biological studies, has a large negative effect of this separation. Instead of simple, rapid, and multigram separations by flash chromatography, extensive semi-preparative high-performance liquid chromatography sequences are now required. Chirality 24:928–935, 2012. © 2012 Wiley Periodicals, Inc.

Featured Compounds

Compound 1
Molecular Weight:	Not Available
Molecular Formula:	Not Available
InChIKey:	Not Available
View compound in article \| Full details \| Search this compound

Compound 5
Molecular Weight:	Not Available
Molecular Formula:	Not Available
InChIKey:	Not Available
View compound in article \| Full details \| Search this compound

Compound 6
Molecular Weight:	423.4783
Molecular Formula:	C25H27O6
InChIKey:	PSGIGHUYRBMGRP-UHFFFAOYSA-N
View compound in article \| Full details \| Search this compound

Compound 2
Molecular Weight:	Not Available
Molecular Formula:	Not Available
InChIKey:	Not Available
View compound in article \| Full details \| Search this compound

Compound 3
Molecular Weight:	Not Available
Molecular Formula:	Not Available
InChIKey:	Not Available
View compound in article \| Full details \| Search this compound

Compound 4
Molecular Weight:	Not Available
Molecular Formula:	Not Available
InChIKey:	Not Available
View compound in article \| Full details \| Search this compound

Compound (Rs,M)-7bb
Molecular Weight:	510.647
Molecular Formula:	C31H30N2O3S
InChIKey:	FBTCOSPNZJECDW-DIPNUNPCSA-N
View compound in article \| Full details \| Search this compound

Compound (Rs,P)-8bb
Molecular Weight:	510.647
Molecular Formula:	C31H30N2O3S
InChIKey:	FBTCOSPNZJECDW-DIPNUNPCSA-N
View compound in article \| Full details \| Search this compound

Compound [(M)-3][PF6]
Molecular Weight:	Not Available
Molecular Formula:	Not Available
InChIKey:	Not Available
View compound in article \| Full details \| Search this compound

Compound [(M)-3aa][PF6]
Molecular Weight:	558.4955
Molecular Formula:	C27H29F6N2O2P
InChIKey:	PTQUHJQNVNGHBE-UHFFFAOYSA-N
View compound in article \| Full details \| Search this compound

Compound [(M)-3bb][PF6]
Molecular Weight:	502.3892
Molecular Formula:	C23H21F6N2O2P
InChIKey:	UEVTYLOEBZSPLB-UHFFFAOYSA-N
View compound in article \| Full details \| Search this compound

Compound [(P)-3][PF6]
Molecular Weight:	Not Available
Molecular Formula:	Not Available
InChIKey:	Not Available
View compound in article \| Full details \| Search this compound

Compound [(P)-3aa][PF6]
Molecular Weight:	558.4955
Molecular Formula:	C27H29F6N2O2P
InChIKey:	PTQUHJQNVNGHBE-UHFFFAOYSA-N
View compound in article \| Full details \| Search this compound

Compound [(P)-3bb][PF6]
Molecular Weight:	502.3892
Molecular Formula:	C23H21F6N2O2P
InChIKey:	UEVTYLOEBZSPLB-UHFFFAOYSA-N
View compound in article \| Full details \| Search this compound

Compound [rac-3][BF4]
Molecular Weight:	Not Available
Molecular Formula:	Not Available
InChIKey:	Not Available
View compound in article \| Full details \| Search this compound

Compound [rac-3aa][BF4]
Molecular Weight:	500.336
Molecular Formula:	C27H29BF4N2O2
InChIKey:	KNEOCGOVLXHFIP-UHFFFAOYSA-N
View compound in article \| Full details \| Search this compound

Compound [rac-3bb][BF4]
Molecular Weight:	444.23
Molecular Formula:	C23H21BF4N2O2
InChIKey:	NANYSCIPWLHMMW-UHFFFAOYSA-N
View compound in article \| Full details \| Search this compound

Compound 7
Molecular Weight:	Not Available
Molecular Formula:	Not Available
InChIKey:	Not Available
View compound in article \| Full details \| Search this compound

Compound 8
Molecular Weight:	Not Available
Molecular Formula:	Not Available
InChIKey:	Not Available
View compound in article \| Full details \| Search this compound

Compound (M)-[3bb][Cl]
Molecular Weight:	392.878
Molecular Formula:	C23H21ClN2O2
InChIKey:	ONRMOWJDVDEHBX-UHFFFAOYSA-M
View compound in article \| Full details \| Search this compound

Compound (P)-[3bb][Cl]
Molecular Weight:	392.878
Molecular Formula:	C23H21ClN2O2
InChIKey:	ONRMOWJDVDEHBX-UHFFFAOYSA-M
View compound in article \| Full details \| Search this compound

Compound [3ba][PF6]
Molecular Weight:	530.4424
Molecular Formula:	C25H25F6N2O2P
InChIKey:	QURZLAFPHRVPTF-UHFFFAOYSA-N
View compound in article \| Full details \| Search this compound

Compound [1b][PF6]
Molecular Weight:	535.4158
Molecular Formula:	C24H24F6NO4P
InChIKey:	QRUFSTUULYTZRW-UHFFFAOYSA-N
View compound in article \| Full details \| Search this compound

Compound (Rs,Sc,M)-7ba
Molecular Weight:	538.7
Molecular Formula:	C33H34N2O3S
InChIKey:	DLPPCUXLIUQKJW-UOSBZTQKSA-N
View compound in article \| Full details \| Search this compound

Compound (Rs,Sc,P)-8ba
Molecular Weight:	538.7
Molecular Formula:	C33H34N2O3S
InChIKey:	DLPPCUXLIUQKJW-UOSBZTQKSA-N
View compound in article \| Full details \| Search this compound

Compound (Rs,Rc,M)-7ba
Molecular Weight:	538.7
Molecular Formula:	C33H34N2O3S
InChIKey:	DLPPCUXLIUQKJW-XPNCQOHCSA-N
View compound in article \| Full details \| Search this compound

Compound (Rs,Rc,P)-8ba
Molecular Weight:	538.7
Molecular Formula:	C33H34N2O3S
InChIKey:	DLPPCUXLIUQKJW-XPNCQOHCSA-N
View compound in article \| Full details \| Search this compound

Compound [6][BF4]
Molecular Weight:	510.283
Molecular Formula:	C25H27BF4O6
InChIKey:	ICNWKRZPUKJRPY-UHFFFAOYSA-N
View compound in article \| Full details \| Search this compound

Compound [rac-3ba][PF6]
Molecular Weight:	530.4424
Molecular Formula:	C25H25F6N2O2P
InChIKey:	QURZLAFPHRVPTF-UHFFFAOYSA-N
View compound in article \| Full details \| Search this compound

View Full Article with Supporting Information (HTML) Get PDF (800K)

JOURNAL TOOLS

JOURNAL MENU

FIND ISSUES

FIND ARTICLES

GET ACCESS

FOR CONTRIBUTORS

ABOUT THIS JOURNAL

SPECIAL FEATURES

Surprisingly Difficult Resolution of N-Methylated Cationic [4]Helicenes