A new synthetic strategy towards dibenzotetraaza[14]annulenes bearing alkoxycarbonyl and aryloxycarbonyl pendant substituents

A new and efficient procedure has been developed for introducing alkoxycarb onyl and aryloxycarbonyl groups at the meso positions of the dibenzotetraaz a[14]annulene Ni(II) complex. Ester substituents have been generated in one -pot, two-step procedure involving successive reactions with oxalyl dichlor ide (or phosgene) and appropriate HO-function-containing substrate. A range of new Ni(IT) complexes equipped with ester groups derived from various al cohols and phenols have been prepared. The method proved to be applicable t o the alcohols and phenols bearing other functional groups e.g. carbonyl (f ormyl, keto), nitro and azo groups, as well as double and triple bonds (all yl, propargyl). Highly lipophilic COOR substituents (where R=n-alkyl (C-14- C-18), cholesteryl and DL-alpha -tocopheryl) have been also incorporated in to the macrocycle. The new products have been characterized by elemental an alysis, ESI and MALDI-TOF MS, IR, H-1 and C-13 NMR data. (C) 2001 Elsevier Science B.V. All rights reserved.