o-Quinonoid Heterocycles: Synthesis and Crystal Structure of 2,3-Dicyano-5,7-bismethylthieno[3,4-b]pyrazine
Journal article, Peer reviewed
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OriginalversjonMolecules 2007, 12:1623-1631 10.3390/12081623
2,3-Dicyano-5,7-bismethylthieno[3,4-b]pyrazine (5), has been obtained as a minor product from reactions of S-nucleophiles with 5,6-di(1-bromoethyl)pyrazine-2,3- dicarbonitrile (3), or from a condensation of 4-hydroxy-2,5-dimethyl-2,3-dihydrothiophen- 3-one (4) with diaminomaleonitrile. The molecular structure of compound 5 has been confirmed by X-ray diffraction. A partial separation of charge causes a donor-acceptor type arrangement of the planar molecules in uniform parallel stacks with an interplanar spacing of 3.334(2) Å at 100 K.