A simple synthesis of 3-phosphonyl-4-aminoquinolines from beta-enaminophosphonates

An easy and efficient synthesis of 4-aminoquinolines substituted with a pho sphorylated group or a phosphine oxide group in the 3-position is described . The key step is a regioselective addition of lithiated beta-enamino phosp honates to isocyanates to give functionalized amides. Subsequent cyclizatio n of these compounds with triphenylphosphine and hexachloroethane in the pr esence of triethylamine afforded substituted 4-aminoquinolines. The deprote ction of N-PMP substituted 4-amino-quinolines with CAN in acetonitrile gave primary 4-aminoquinolines. (C) 1999 Elsevier Science Ltd. All rights reser ved.