Synthesis of Polysubstituted Benzenes via the Vinylogous Michael Addition of Alkylidenemalononitriles to 2‐(1,3‐Dioxo‐1H‐inden‐2(3H)‐ylidene)malononitrile |
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| Authors: | Abdolali Alizadeh Hadi Sedighian Seyed Yasub?Hosseini Long‐Guan Zhu |
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| Affiliation: | 1. Department of Chemistry, Tarbiat Modares University, P.O. Box 14115‐175, Tehran, Iran, (phone: +98‐21‐88006631;2. fax: +98‐21‐88006544);3. Department of Chemistry, Zhejiang University, Hangzhou 310027, P.?R. China |
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| Abstract: | An efficient synthesis for polysubstituted benzenes was successfully developed by the reaction of ninhydrin (=2,2‐dihydroxyindane‐1,3‐dione), malononitrile (=propanedinitrile), and alkylidenemalononitrile. The method involves vinylogous Michael addition of alkylidenemalononitrile to 2‐(1,3‐dioxo‐1H‐inden‐2(3H)‐ylidene)malononitrile, which formed by condensation of malononitrile and ninhydrin in the presence of Et3N, and the alcoholic solvent has participated in the reaction as a reagent. The method has the advantages of good yields and of not requiring a metal catalyst. The structures were confirmed spectroscopically (IR, 1H‐ and 13C‐NMR, and EI‐MS) and by elemental analyses, and, in the case of 2c , by X‐ray crystallography. A plausible mechanism for this reaction is proposed (Scheme). |
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| Keywords: | Ninhydrin Indane‐1 3‐dione 2 2‐dihydroxy‐ Malononitrile Michael addition Benzenes polysubstituted |
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