New route to enantiopure MαNP acid, a powerful resolution and chiral 1H NMR anisotropy reagent

Junpei Naito, Hiromi Taji, Satoshi Sekiguchi, Miwa Watanabe, Shunsuke Kuwahara, Masataka Watanabe, Nobuyuki Harada

    Research output: Contribution to journalArticlepeer-review

    8 Citations (Scopus)


    MαNP acid (±)-1, 2-methoxy-2-(1-naphthyl)propionic acid, was enantioresolved by the use of phenylalanine (S)-(-)-4; a diastereomeric mixture of amides formed from acid (±)-1 and amine (S)-(-)-4 was easily separated by fractional recrystallization and/or HPLC on silica gel, yielding amides (R;S)-(-)-5a and (S;S)-(+)-5b. Their absolute configurations were determined by X-ray crystallography by reference to the S configuration of the phenylalanine moiety. Amide (R;S)-(-)-5a was converted to oxazoline (R;S)-(+)-8a, from which enantiopure MαNP acid (R)-(-)-1 was recovered. In a similar way, enantiopure MαNP acid (S)-(+)-1 was obtained from amide (S;S)-(+)-5b. These reactions provide a new route for the large-scale preparation of enantiopure MαNP acid, a powerful chiral reagent for the enantioresolution of alcohols and simultaneous determination of their absolute configurations by 1H NMR anisotropy.

    Original languageEnglish
    Pages (from-to)335-343
    Number of pages9
    Issue number5
    Publication statusPublished - 2007 May 8


    • 2-methoxy-2-(1-naphthyl)propionic acid
    • Absolute configuration
    • Diastereomeric amides
    • Fractional recrystallization
    • HPLC separation on silica gel
    • MαNP acid
    • Oxazoline
    • Phenylalaninol
    • X-ray crystallography

    ASJC Scopus subject areas

    • Analytical Chemistry
    • Catalysis
    • Pharmacology
    • Drug Discovery
    • Spectroscopy
    • Organic Chemistry


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