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Multi-substituted conjugated dienes are useful intermediates for the synthesis of various biologically active compounds and functional materials. In this study, one-pot synthesis of multi-substituted 2,4-butadienes was achieved via the reaction of ketene dithioacetal, 3,3-bis(methylsulfanyl)methylenemalononitrile (1), with a variety of aromatic ketone compounds. Complete stereoselective (2Z,4E)-2,4-dienamide (3a) was obtained from 1 with 4-methoxyacetophenone (2a) in the presence of sodium hydroxide as a base in DMSO. Similarly, the reaction of 1 with electron-rich aromatic ketones or heterocyclic aromatic ketones gave (2Z,4E)-2,4-dienamide compounds as the sole product in 31–61 yields. In the proposed synthetic sequence, the process consists of a cascade reaction involving the addition of 1 to ketone compound, elimination of methylthiolate anion from 1, subsequent intramolecular cyclization and ring opening reaction by readdition of methylthiolate anion. Moreover, all the (2Z,4E)-2,4-dienamide compounds (3a–j) obtained in this study exhibited blue-green fluorescence in the solid state, which suggested the possibility of obtaining functional conjugated dienes by this novel one-pot synthetic method. [ABSTRACT FROM AUTHOR]

A novel series of heterocycles were obtained through the condensation reaction of 4-methylthiomaleimides with pyrroles and indoles. The newly synthesized compounds exhibit their major electronic absorption peaks ranging 435-504nm in solution at room temperature. Time-dependent density-functional theory (TDDFT) calculations were systematically performed in order to elucidate their structure-color relationships, using a set of exchange-correlation (XC) functionals. The TDDFT computational scheme employing PCM-TDDFT/6-31+G(d,p)//DFT/6-311G(d,p) level of theory gave qualitatively satisfactory results in their λmax predictions. [ABSTRACT FROM AUTHOR]