Formation of water-soluble sulfonated azacalix[4]arenes from cyanuric chloride

Addition of cyanuric chloride 2 (2,4,6-trichlorotriazine) to 4,6-diaminobenzene-1,3-disulfonic acid 1 gives a bis-triazine 3 which may be cyclised with diaminoarenes to yield water-soluble azacalix[4]arenes 5a–d. Alternatively, double substitution of chloride from the bis-triazine 3 yields new bis-triazine derivatives which may likewise be cyclised to functionalised azacalixarenes bearing functionalised side chains.