Synthesis of New Functionalized 1,4-Dihydroquinolines and Pyrimido[4,5-b]quinolines

Abstract

The reaction of N-alkylisatoic anhydrides with malononitrile in pyridine led to formation of new 2-amino-1-alkyl-4-oxo-1,4-dihydroquinoline-3-carbonitriles. Following treatment of these compounds with an excess of aliphatic carboxylic acids in the presence of POCl₃ under reflux gave novel 2,10-dialkylpyrimido[4,5-b]quinoline-4,5(3H,10H)-diones with high yields. It is probable that synthesis of the latter products proceed via the tandem intramolecular Pinner–Dimroth rearrangement. All synthesized compounds were characterized by spectral and microanalytical data.