Synthesis of [Poly(2-pyridyl)-Substituted]-1-azaazulenes

2-(2-Pyridyl)-1-azaazulenes were derived from 2-bromo- or 2-iodo-1-azaazulenes and 3-(2-pyridyl)-1-azaazulenes were derived from 3-iodo-1-azaazulenes by Suzuki coupling. Reaction of 3-iodo-1-azaazulenes with B(NPDEA) gave corresponding 3-(2-pyridyl)-1-azaazulenes together with 3-borylated-2-chloor-1-azaazulene (9a) or 3,3’-bi(2-methoxy-1-azaazulene) (10b). Reactions of 8-(2-pyridyl)-1-azaazulene with 2-pyridyllithium gave 4,8-di(2-pyridyl)- and 6,8-di(2-pyridyl)-1-azaazulenes. Reactions of 4,8-di(2-pyridyl)-1-azaazulene with 2-pyridyllithium gave 4,6,8-tri(2-pyridyl)-1-azaazulene. The reactivity of the seven-menbered ring is C8 > C6 > C4. Reaction of 3-(2-pyridyl)-1-azaazulenes with 2-pyridyllithium gave 3,4-di(2-pyridyl)- and 3,8-di(2-pyridyl)-1-azaazulenes