- Synthesis of enantiopure 6-methoxy-2-naphthylglycolic acid and its application as a resolving agent
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6-Methoxy-2-naphthylglycolic acid (6-MNGA) was designed as a novel acidic resolving agent, on the model of 2-naphthylglycolic acid (2-NGA). Enantiopure 6-MNGA was easily obtained from commercially available 2-bromo-6- methoxynaphthalene through four steps and was found to show a better chiral recognition ability for racemic 1-arylethylamines than the prototype 2-NGA did. The X-ray crystallographic analyses of less-soluble diastereomeric salts revealed that the introduction of a methoxy group at the 6-position of the 2-NGA skeleton made CH/π interaction(s) effective between 6-MNGA molecules and also between the 6-MNGA molecule and the target amine molecule. The methoxy group was also found to contribute to the realization of effective van der Waals interaction. These interactions played important roles for the stabilization of the less-soluble diastereomeric salts to improve the chiral recognition ability of 6-MNGA, compared to that of 2-NGA.
- Shimada, Takayoshi,Kobayashi, Yuka,Saigo, Kazuhiko
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p. 3807 - 3813
(2007/10/03)
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- New Syntheses of Ibuprofen and Naproxen
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A new route for the synthesis of α-arylpropionic acids, in particular for the two most important non-steroidal antiinflammatory compounds Ibuprofen (5) as well as racemic and optically active Naproxen (12), has been developed.N-(1-Arylethyl)formamides 2, 9 are dehydrated to the corresponding isocyanides 3, 10, and these are rearranged by flash pyrolysis to α-arylpropionitriles 4, 11 which are converted into α-arylpropionic acids 5, 12 by hydrolysis under standard conditions.The intermediate 1-(6-methoxy-2-naphthyl)-ethylamine is resolved via its tartrate or mandelic salts. Key Words : Isocyanide - cyanide rearrangement / Ibuprofen / Naproxen / Optically active 1-arylethylamines
- Wolber, Erwin K. A.,Ruechardt, Christoph
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p. 1667 - 1672
(2007/10/02)
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