Novel Conversion of 4-Aminoquinolines to New Tricyclic (<i>R,S</i>)-3-Methylazeto[3,2-<i>c</i>] Quinolin-2(2a<i>H</i>)-Ones and Versatile One Step Synthesis of <i>N</i>-(Quinolin-4-yl) Carbamates from 4-Aminoquinolines

Abstract

Reaction of 4-aminoquinolines with 4-nitrophenyl chloroformate have resulted in finding a novel transformation of 4-aminoquinolines to tricyclic (R,S)-3-methylazeto[3,2-c]quinolin-2(2aH)-ones. The structure of azeto-quinolinone was determined via spectroscopic and chemical methods. Various alcohols were used as nucleophiles to open the 1-azetinone ring to give the corresponding N-(quinolin-4-yl)carbamates in good yields. We also found a new and versatile one step synthesis of N-(quinolin-4-yl)carbamates by reacting 4-aminoquinolines with alkyl chloroformates in the presence of anhyd K2CO3 in acetonitrile.