Synthesis of macrocycles derived from vanillin and isovanillin

摘要

Readily available vanillin 1 and isovanillin 2 have been exploited for hte first time to synthesise thia and aza-bridged macrocycles.Utilising a common approach,1 and 2 are first converted into the corresonding key intermediates,dicholoro compounds 5 and 10.Cyclocondensations of these moelcules with Na_2S under high dilution provide thia-bridged macrocycles 6 and 11 with p-toluenesulphonamide under basic condition,the aza-bridged macrocycles 7 and 12,respectively are obtained.The structures are fully supported by elemental analysis,mass and high resolution NMR data.Variable NMR measurements on 6 and 11 suggest that these amcrocycles are conformationally mobile even at -55degC on the NMR time scale.