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Towards a rational design for resolving agents. Part V: Substituent effects in the resolution of ephedrine using a series of cyclic phosphoric acids

✍ Scribed by Albertus D. van der Haest; Hans Wynberg; Frank J. J. Leusen; Alle Bruggink

Publisher
Elsevier Science
Year
2010
Tongue
English
Weight
569 KB
Volume
112
Category
Article
ISSN
0165-0513

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✦ Synopsis

Abstract

The effects of various aromatic substituents in both ephedrine and a cyclic phosphoric acid on the quality of resolution via diastereomeric salt formation are investigated. The diastereo‐selective synthesis of a novel series of chloro‐substituted ephedrines is described. These chloroephedrines can be resolved efficiently with some of the cyclic phosphoric acids. By studying the physical properties of nineteen pairs of diastereomeric salts, we show that the quality of the resolution depends mainly on the aromatic substituent of the cyclic phosphoric acid, whereas substituents at the phenyl ring of ephedrine play a secondary role.

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Towards a rational design of resolving a
Towards a rational design of resolving agents. Part IV. Crystal packing analyses and molecular mechanics calculations for five pairs of diastereomeric salts of ephedrine and a cyclic phosphoric acid
✍ Frank J. J. Leusen; Hubert J. Bruins Slot; Jan H. Noordik; Albertus D. van der H 📂 Article 📅 2010 🏛 Elsevier Science 🌐 English ⚖ 696 KB

## Abstract Detailed structural studies of five pairs of diastereomeric salts of ephedrine and halogen‐substituted chiral cyclic phosphoric acids indicate a correlation between the efficiency of the resolution process and the lattice energy difference between the salts of a diastereomeric pair. Att