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Discrimination in resolving systems. III: Pseudoephedrine-mandelic acid by Edward J. Valente; Pamela M. Williams-Knight; Michael C. Moore is a Chemistry article available to read on EtoBox.

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+)-(1S;2S)-Pseudoephedrine and racemic mandelic acid form three distinct diastereomeric salts from solutions in 95% ethanol. The least-soluble phase, a hemihydrate, contains the (2R)-mandelate. A salt phase of intermediate solubility is the unsolvated double salt, containing both the (2R)-and the (2S)-mandelate. The mostsoluble salt phase contains the (2S)-mandelate. Mandelate configuration and order of solubility (based on the heats of fusion) is inverted from that found in the same system synthesized from chiral base and acid, and then crystallized from benzene solution. The (2R)-mandelate hemihydrate (-H 2 O at 349.5K, mp 391K), monoclinic, P2 1 , a = 6.788( 5), b = 29.415(35), c = 9.488(10)Å, ␤ = 108.91(8)°, Z = 4 (2 ion-pairs/asymmetric unit). Intermediate double salt (2S)-and (2R)-mandelate, mp 377.6K, anorthic, P1, a = 7.758(4), b = 9.966(5), c = 13.366(6)Å, ␣ = 72.99(4), ␤ = 79.98(4), ␥ = 70.51(4)°, Z = 1 (2 ion-pairs/ asymmetric unit). The (2S)-mandelate (mp 386.2K), orthorhombic, P2 1 2 1 2 1 , a = 7.079( 6), b = 13.443(10), c = 18.820( 14)Å, Z = 4 is identical to a salt made from a combination of enantiomeric moieties from benzene solution. While differing from ephedrine

Who reads Discrimination in resolving systems. III: Pseudoephedrine-mandelic acid?

Author

Edward J. Valente; Pamela M. Williams-Knight; Michael C. Moore

Publisher

John Wiley and Sons; Wiley (John Wiley & Sons); John Wiley & Sons Inc.; Wiley (ISSN 0899-0042)

Published

1998

Language

EN

Field

Chemistry (Physical Sciences)