One-pot Synthesis Of Substituted △～1-Pyrrolines In Aqueous Media

â–³~1-pyrroline unit is found in numerous natural products along with important bio- and pharmacological activities, for example pheromones, alkaloids, steroids, hemes, and chlorophylls. Also, the â–³~1pyrroline unit is an important synthetic building block in a large variety of functionalized aza-heterocycles for their pro-chiral center as part of a cyclic imine, which is amendable to further transformations.A facile and efficient one-pot synthesis of substituted â–³~1-pyrrolines in aqueous media has been developed. With the treatment of aqueous NaOH in N,N-dimethylformamide (DMF), a range of chalcones 1 reacted with nitroalkanes 2 via Michael addition reactions at room temperature. Without separation of the reaction mixture, the resulting adducts were reduced in situ with Zn/HCl (aq.) and subsequently underwent an intramolecular cyclization affording the corresponding substituted â–³~1pyrrolines 4 in high yields...