Efficient three-component one-pot synthesis of fully substituted pyridin-2(1H)-ones via tandem Knoevenagel condensation-ring-opening of cyclopropane-intramolecular cyclization

摘要

An efficient synthesis of fully substituted pyridin-2(1H)-ones was developed via three-component one-pot reactions of readily available 1-acetyl-1-carbamoyl cyclopropanes, malononitrile and cyclic secondary amines.rnThe utility of cyclopropane derivatives in organic synthesis has been recognized due to their well-known "unsaturated" character, which can lead to a variety of ring-opening reactions under the influence of a wide range of reactive species, such as electrophiles, nucleophiles, and radicals. In our previous work, the ring-opening/ring closure reactions of 1-acetyl-1-carbamoyl cyclopropanes were developed for the synthesis of furoquinolines under metal catalyst, and halogenated pyridin-2(1H)-ones under Vilsmeier conditions. In conjunction with these studies and our continued interest regarding the synthetic potential of double EWGs (electron-withdrawing groups) activated cyclopropanes towards various carbo- and heterocycles, we explored the Knoevenagel reaction of 1-acetyl-1-carbamoyl cyclopropanes and malononitrile in the presence of piperidine. As a result of the research, we developed a straightforward and efficient synthesis of fully functionalized pyridin-2(1H)-ones of types 2 and 3 via a one-pot three-component tandem reaction.