All these products possess a keto group which will allow further transformations. The same concept was applied for the synthesis of the S-shaped terpyridine 25. The reaction of the Mannich base 21 with 1,3-cyclohexanedione yielded the heptacyclicterpyridine 22, which is a key intermediate for the synthesis of torands and other tridentate clefts. The ketone 12a was used for the synthesis of the quaterpyridine