Synthesis of straight arm chains substituted dibenzo-21-crown-7 derivatives

Abstract

A series of straight arm chains substituted dibenzo-21-crown-7 derivatives 2a–c, 3a–c, and 5a–c have been synthesised by the Huang Minlon method or reduction with sodium borohydride from the corresponding dibenzo-21-crown-7 bridged diketones 1a–c and 4a–c, which were obtained by diacylation of dibenzo-21-crown-7 with excessive mono- or dicarboxylic acids in the presence of polyphosphoric acid. All new compounds were characterised by IR, MS, 1H NMR and elemental analysis.