Asymmetrische Katalyse, 134 [1]. Naproxen-Derivate durch enantioselektive Decarboxylierung Asymmetric Catalysis, 134 [1]. Naproxen Derivatives by Enantioselective Decarboxylation
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چکیده
2-Aryl-substituted propionic acids, such as the important anti-inflammatory agent Naproxen, exist in two enantiomeric forms. The (S^-enantiomer of 2-(6-methoxynaphth-2-yl)propionic acid 1 is about 28 times more effective than the (/?)-enantiomer. A new catalytic method to synthesize Naproxen (S)-l involves the enantioselective decarboxylation of suitably substi tuted malonic acid derivatives. Thus, 2-(6-methoxynaphth-2-yl)-2-methylmalonic acid 6 and its monoester 7 were stirred in THF with catalytic amounts of chiral bases, which induced decarboxylation. After work-up, optical inductions up to 39.8% ee were found in the resulting products 1 and 9. The optically active bases may be fully recycled by extraction.
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