ORGN 435 |
| Previously our laboratory has determined that sodium borohydride in isopropanol is not only a good reagent for reducing the conjugated alkene of 1,1-dicyanoalkenes but is also an excellent catalyst for the Knoevenagel condensation of malononitrile with a range of ketones and aldehydes. This reductive alkylation procedure had limitations with various aromatic aldehydes because the sodium borohydride would competitively reduce the aldehydes. Recently, we have solved the limitation of this reductive alkylation by utilizing aqueous ethanol for the condensation in a new one-pot procedure. We applied this improved one-pot synthesis using various 2-hydroxybenzaldehydes (salicylaldehydes) where intramolecular cyclization occurs following the condensation step and various 4H-Chromenes are formed. 2-Hydroxybenzaldehyde (salicylaldehyde), malononitrile, and sodium borohydride were employed and the intermediate and product steps of the reaction were optimized. Current progress in our laboratory on this reaction and reactions of the intermediates and novel products will be discussed. |
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Heterocycles and Aromatics, Molecular Recognition and Self Assembly
8:00 PM-10:00 PM, Tuesday, April 8, 2008 Morial Convention Center -- Hall A, Poster
Division of Organic Chemistry |