Browse views: by Year, by Function, by GLF, by Subfunction, by Conference, by Journal

The use of MPA amide for the assignment of absolute configuration of a sterically hindered cyclic secondary amine by 'mix and shake' NMR method.

Gao, Jinhai and Haas, Hansjoerg and Wang, Kate Yaping and Chen, Zhuoliang and Breitenstein, Werner and Rajan, Srinivasan (2008) The use of MPA amide for the assignment of absolute configuration of a sterically hindered cyclic secondary amine by 'mix and shake' NMR method. Magnetic Resonance in Chemistry : MRC, 46 (1). pp. 17-22. ISSN 1097-458X

Abstract

We present here a new method using methoxyphenylacetic acid (MPA) as the chiral derivatizing agent (CDA) for the assignment of absolute configuration of cyclic secondary amines. The MPA amides were prepared using the purification-free 'mix and shake' method. A detailed conformational analysis for the two diastereomeric amides was conducted by 2D NMR experiments and molecular mechanics calculations. We have established that, in the most stable conformation of each syn rotamer of MPA amides, the H-alpha in the MPA moiety is oriented toward the bulky substituent group at the asymmetric carbon in the chiral amine, presumably to avoid steric and/or electrostatic interactions. The observed NMR data were correlated with the conformational model to allow unambiguous assignment of absolute configuration of secondary amines. The results demonstrate that the MPA can be used as a useful CDA in the case of sterically crowded cyclic secondary amines from which the MTPA amides are usually difficult to make. Copyright (c) 2007 John Wiley & Sons, Ltd.

Item Type: Article
Related URLs:
Additional Information: archiving not allowed on institutional repository
Keywords: 1H NMR; absolute configuration; cyclic secondary amine; MPA amide
Related URLs:
Date Deposited: 14 Dec 2009 13:51
Last Modified: 14 Dec 2009 13:51
URI: https://oak.novartis.com/id/eprint/919

Search

Email Alerts

Register with OAK to receive email alerts for saved searches.