Synthesis of 1,2-dihydroacridines based on chloroquinoline-3-carbaldehyde and diketene under catalyst-free reaction.

A green, facile, and efficient method for the synthesis of novel 1,2-dihydroacridine-2-carboxamide derivatives was effectively performed via a one-pot pseudo-five component cascade reaction involving 2-chloroquinoline-3-carbaldehyde, 1-phenyl-2-(triphenylphosphoranylidene)ethanone, diketene, and several primary amines in ethanol at 70 °C, in one pot reaction. This novel effective cascade reaction was accomplished probably via a sequence of Wittig reaction/SN reaction/Michael addition/intramolecular C-cyclization and imine hydrolysis. The advantages of this method are operational simplicity, atom economy, short reaction times, facile work-up procedure, and very high yields. [ABSTRACT FROM AUTHOR]