Synthesis of 2-(3-cyano-5-hydroxy-5-methyl-4-vinylene-1H-pyrrol-2(5H)-ylidene)malononitriles – novel functionalized analogs of tricyanofuran-containing (TCF) push–pull chromophores

2-(3-Cyano-5-hydroxy-4,5-dimethyl-1H-pyrrol-2(5H)-ylidene)malononitrile was synthesized by the interaction between malononitrile dimer and diacetyl. It reacts with aldehydes in ethanol in the presence of ammonium acetate at room temperature and results 2-(3-cyano-5-hydroxy-5-methyl-4-vinylene-1H-pyrrol-2(5H)-ylidene)malononitriles in 66–86% yield. The developed method is of interest as a promising approach to a novel group of push–pull chromophores, which are functionalized analogs of widely used chromophores of the tricyanofuran (TCF) series.GRAPHICAL ABSTRACT     

Regioselective Intramolecular Carbon-Hydrogen Insertion in Copper-Catalyzed Carbenoid Decompositions of cis-1-Methyl-3-Arylcyclohexane-1-Diazomethyl Ketones : Some Synthetic Applications

Recently, we have developed¹ a new route for the stereo-specific introduction of an angular carboxyl or functionalized methyl groups² in a rigid hydrophenanthrene moiety. The key step in this approach is a regioselective intramolecular α-keto carbenoid insertion across the benzylic C-H bond (at C-4a) in CuSO₄-catalyzed thermal decomposition of the diazoketones and to the corresponding tetracyclic ketones and in moderate to good yields. A modified procedure³ of carbenoid decomposition of these diazoketones, in the presence of Cu₂O under irradiation with tungsten filament lamp, improves the yields of the desired C-H insertion products. Thus, the ketones and have been prepared now in consistently higher yields (53-55%) from the pure diazoketones , m.p. 125-127°, and , m.p.