In the presence of water and 1,4-diazabicyclo[]octane, several aldehydes and cyclic ketones underwent efficient Knoevenagel condensation with malononitrile and ethyl cyanoacetate to produce the respective -unsaturated systems within fairly short time periods. As a result, high yields of conjugated products were easily obtained. Products could be engaged in a Gewald reaction, either stepwise or in situ, to produce efficiently their respective 2-aminothiophenes within 4–7 h. |
