Synthesis of Polysubstituted Benzenes<i>via</i>the Vinylogous<i>Michael</i>Addition of Alkylidenemalononitriles to 2-(1,3-Dioxo-1<i>H</i>-inden-2(3<i>H</i>)-ylidene)malononitrile
AbstractAn 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).
作者:SANDBERG R.、 DOMEIJ K.-E.、 STENING G.、 WILLMANN N.、 AKERMAN B.
DOI:——
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KOECKRITZ P.; SCHMIDT L.; LIEBSCHEK J., J. PRAKT. CHEM., 1987, 329, N 1, 150-156
作者:KOECKRITZ P.、 SCHMIDT L.、 LIEBSCHEK J.
DOI:——
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Symmetrical and unsymmetrical donor–acceptor–donor organic dyes: Design, synthesis and characterization. Engineering panchromic absorbance
作者:Akhil Gupta、Abdelselam Ali、Ante Bilic、Th Birendra Singh、Richard A. Evans
DOI:10.1016/j.dyepig.2014.04.008
日期:2014.9
central acceptor were made. The central acceptors were dicyanovinylidene and 1,3-diethylthiobarbituric acid derivatives of 2-indanone in the set of symmetrical dyes and dicyanovinylidene in unsymmetrical dyes. The different acceptors allowed the tuning of optoelectronic properties. All the new materials were soluble in variety of organic solvents, such as chloroform, toluene and chlorobenzene. With