Fusion Reaction for Synthesis of Dumbbell-shape Compounds Containing Two Units of 4,4′-Bipyridine Bridged by 2,2′-Bipyridine

In the synthesis of N-substituted derivatives of 4,4′-bipyridine(2a～2c) via the fusion reaction of tosylate with 4,4′-bipyridine, it was found that the reaction was completed within 30 min, but the molar ratio of the tosylate to 4,4′-bipyridine had significantly influence on the yields of N-substituted derivatives of 4,4′-bipyridine. If the ratio was 1: 1, N, N′-disubstituted derivatives of 4,4′-bipyridine was major products. Increasing the ratio of tosylate to 4,4′-bipyridine, the yields of (2a～2c) were increased. When the ratio was 1:10, it generated the N-substituted derivatives of 4,4′-bipyridine(2a～2c) in about 90% yields. By reacting intermediates (2a～2c)(0. 6 mmol) with 4,4′-di(bromomethyl)-2,2′-bipyridine (0.3 mmol) according to the same method as above, the dumbbell-shape compounds containing two units of 4,4′-bipyridine bridged by 2,2′-bipyridine(3a～3c) were obtained in 79%～87%.