High-yield one-step synthesis of donor acceptor cyanostilbenes

CHED 581

Desmond H. Murray, murrayd@andrews.edu1, Kenneth B. Fletcher, fletchek@andrews.edu1, and Ruth Walker Jiyani, jiyani@andrews.edu2. (1) Department of Chemistry and Biochemistry, Andrews University, Berrien Springs, MI 49104, (2) Clinical & Laboratory Sciences, Andrews University, Berrien Springs, MI 49104
We report here a new and improved one-step method for synthesis of donor–acceptor cyanostilbenes. Our method is based on literature reports involving direct base-promoted condensation reactions of tolunitriles with benzaldehydes. However, these literature methods used toxic solvents, gave product mixtures and low yields. We have found that tolunitriles react with donor-substituted aromatic aldehydes in high yielding reactions that avoid use of toxic solvents and without the need for inert atmosphere. The keys to this reaction are use of anhydrous DMF solvent and the phase transfer agent – tris(3,6-dioxaheptyl)amine (TDA). Under our reaction conditions high yields were obtained with a number of amino-substituted aromatic aldehydes as well as ferrocenecarboxaldehyde and para-anisaldehyde. Further development of this method to investigate its synthetic generality for high yield, one-step preparation of other donor-acceptor stilbenes is currently in progress.