Urease: a highly efficient biocatalyst for synthesis of polyhydroquinolines and polyhydroacridines from the ammonia formed in situ.

Urease, a nickel-dependent enzyme, has a powerful catalytic activity to decompose urea into ammonia via hydrolysis reaction under mild condition. In the present work, urease was employed for the synthesis of two series of polyhydroquinoline and polyhydroacridine derivatives via one-pot condensation of the ammonia generated in situ from urea, aryl aldehydes, and dimedone or ethyl acetoacetate (i.e., Hantzsch-type reaction) in water under mild green condition. The valuable features of this enzymatic method are mild reaction conditions, short reaction times, wide substrate toleration, and high yield of products. The present work provides a novel enzymatic catalysis to synthesize polyhydroquinolines and polyhydroacridines and expands the application of urease in organic synthesis.