Practical Outcome of Azaphthalimide Reduction with Zn/AcOH at Various Temperatures

Author(s): Mikhail Krasavin, Dmitry V. Kravchenko, Tatiana D. Talismanova, Vladimir V. Koleda, Olga Ushakova, Vladislav Z. Parchinsky.

Journal Name: Letters in Organic Chemistry

Volume 3 , Issue 5 , 2006

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Reduction of 4-aza- and 5-azaphthalimides with Zn dust in acetic acid resulted in two distinct outcomes: i) in the 4-aza series, the reduction process stopped at the stage of 3-hydroxy-4-azaisoindolin-1- ones (isolated in 69-90% yield), presumably, stabilized by an intramolecular hydrogen bond; more forcing condition (110, 2 days) are required to obtain 4-azaisoindolin-1-ones; ii) in the 5-aza series, even at low temperatures (∼10), overreduction could not be avoided; practical yields of 4-azaisoindolin-1-ones (59- 85%) were achieved using elevated temperatures (50°C). The method described offers a practical alternative to hitherto reported sodium borohydride reduction of 4-azaphthalimides, which suffers from poor selectivity and isolated yields. Reductive manipulation of 5-azaphthalimides was studied for the first time.

Keywords: Azaphthalimides, chemoselective reduction, isoindolones, intramolecular hydrogen bond, combinatorial compound libraries

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Article Details

Year: 2006
Page: [379 - 383]
Pages: 5
DOI: 10.2174/157017806776611890
Price: $65

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