TY - JOUR T1 - Cascade synthesis of 2-cyanoacrylamides through deacetalization and/or knoevenagelcondensation followed by selective monohydration of acetals and aldehydes over solid acidferrites JF - Chemcatchem Y1 - 2016 A1 - Kamble, Sumit B. A1 - Rode, Chandrashekhar V. AB - A new protocol of cascade synthesis for biologically active 2-cyanoacrylamides (1) was developed. The reaction proceeds over a novel magnetically retrievable solid-acid composite of iron oxide, poly(vinylpyrrolidone) and phosphotungstic acid (Fe3O4/PVP-PWA) in AcOH-H2O medium under reflux conditions. This transformation is facilitated through single-site Bronsted acid catalyzed cascade reactions involving deacetalization and/or Knoevenagel condensation followed by selective monohydration of nitriles starting from acetals (5) and aldehydes (2) with malononitrile (3). A series of aldehydes, dimethyl and diethyl acetals, along with some heterocyclic aldehydes were successfully transformed to 2-cyanoacrylamides with >95% yields. TEM images confirmed the coating of the PVP over nanosized Fe3O4. Stereoselective monohydration of 2-benzylidenemalononitriles (4) to E isomers was demonstrated by NOESY experiments. The catalyst could be efficiently recycled seven times on employment of both acetals and aldehydes as substrates, as a result of its magnetic nature. VL - 8 IS - 16 U3 - Foreign U4 - 4.724 ER -