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Recently, the construction of the trisubstituted olefin-type probe molecules has elicited the attention of many researchers. However, the synthesis of the trisubstituted olefin-type probes containing two <i>N</i>-heterocycles simultaneously has been rarely reported. In this study, starting from the inexpensive mucobromic acid <b>1</b> and <i>N</i>-heterocyclic compound <b>2</b>, we first utilized a simple one-step reaction to synthesize a series of trisubstituted olefin-type compounds <b>3</b> simultaneously bearing with the structure of two <i>N</i>-heterocyclic rings in the absence of transition metal catalysts with a yield of 62–86%. The optimal reaction conditions were systematically explored, and the structure of the obtained compounds <b>3</b> were well characterized with ¹H NMR, ¹³C NMR, X-ray single-crystal and HR-MS. The preliminary observation showed that, in the presence of base, mucobromic acid <b>1</b> reacts as its ring-opening structure, and the successive nucleophilic substitution reaction and Michael addition reaction can generate the target product <b>3</b>. Considering that the aldehyde group in the molecular structure of the trisubstituted olefin-type compounds <b>3</b> may react with malononitrile, we carried out some relevant investigations so as to realize the visual detection of malononitrile. Interestingly, among the products, compounds <b>3a</b>–<b>3c</b> can be prepared in portable test strips through a simple process and used to achieve the naked-eye detection of malononitrile in environmental systems as designed.