Synthesis of [Poly(2-pyridyl)-Substituted]-1-azaazulenes
摘要:
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-pyridyl lithium 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.
Effective Methods for Introducing Some Aryl and Heteroaryl Substituent onto 1-Azaazulene Nuclei
摘要:
Introduction of aryl and heteroaryl groups onto 1-azaazulene ring was achieved by addition-elimination reaction and Suzuki coupling. Reaction of 2-chloro-1-azaazulenes with 2-aryllithium and 2-heteroaryllithium followed by dehydrogenation with o-chloranil gave 8-aryl- and 8-heteroaryl-2-chloro-1-azaazulene in good yields. Suzuki coupling of 3-iodo-1-azaazulenens with phenylboronic acid in the presence of Pd catalyst afforded 3-phenyl-1-azaazulenes in excellent yield. Suzuki coupling of 2-bromo-1-azaazulenes with phenylboronic acid gave 2-phenyl-1-azaazulenes. Suzuki coupling of 2,3-dibromo-1-azaazulene with phenylboronic acid preferentially occurred at C-2. Reaction of 3-iodo-1-azaazulene with bis(pinacolato)diboron produced 3,3'-bis(1-azaazulene) derivative.
Reaction of 2-chloro-1-azaazulenes with 2-pyridyllithium followed by dehydrogenation by chloranil gave 8-(2-pyridyl) -1-azaazulene (2). Formation of metal complexes (M = Cu, Fe, Pd) of 2 was achieved. The reaction of 2 with Cu(I) gave 1:1 -complex (3) and 2:1-complex (4). Complex (3) was deduced to have a polymeric chain structure with the copper center is +1. The ESR spectrum study of 4 showed that the copper center is +2. The structure of 4 was decided by X-Ray structural analysis and it is shown that the complex takes a trigonal bi-pyramidal structure.