Synthesis of new benzo-substituted macrocyclic ligands containing quinoxaline subunits

The macrocyclic Schiff bases 20-25 were prepared by cyclocondensation of th e bis aldehydes 12-15 with the appropriate diaminoalkanes 17-19. Reduction of the latter with NaBH4 afforded the corresponding azacrown ethers 27-30. Heating of the aldehydes 12-16 in refluxing acetic acid afforded the corres ponding 2,3-bis(benzofuranyl)quinoxalines 33-37. Nucleophilic reaction of t he his phenols 45-48, 54, 56, 57 with the appropriate dihalo compounds 1, 3 8 afforded the corresponding macrocyclic diamides 49-52 and 1,omega-bis-[qu inoxalino(2,3-b)benzoxazepino-13-on-yl]alkanes 60, 61, respectively. (C) 20 00 Elsevier Science Ltd. All rights reserved.