C3-Symmetric Pyridine and Bipyridine Derivatives: Simple Preparation by Cyclocondensation and 2D Self-Assembly at a Solution–Graphite Interface
摘要:
The efficient preparation of four C-3-symmetric (star-shaped) pyridine and bipyridine derivatives is reported. The key steps are Suzuki couplings of 4-pyridyl nonaflates with 4-acetyl-phenylboronic acid followed by an acid-promoted cyclocondensation reaction converting the methyl ketone moiety into the central benzene ring of the target compounds. Based on STM studies at a graphite-solution interface the two-dimensional arrangements of the compounds are discussed, showing the influence of the pyridine substitution pattern.
Three-Component Synthesis of Perfluoroalkyl- or Perfluoroaryl-Substituted 4-Hydroxypyridine Derivatives and Their Palladium-Catalyzed Coupling Reactions
couplings. Suzuki reactions at C-4 and C-3 of the pyridine ring proceeded with moderate to high yields. In addition, Suzuki−Miyaura, Stille, or Buchwald−Hartwig couplingreactions have also been studied and afforded the corresponding highly substituted pyridine derivatives. Starting from an arylated propargylic ether the three-componentreaction led to a pentasubstituted 4-hydroxypyridine derivative that
A mechanistically unique three-componentsynthesis provides a variety of functionalized pyridine derivatives in fair to excellent yields. The scope of this reaction was studied with respect to the alkoxyallene, the nitrile, and the carboxylic acid. Due to the 4-hydroxy group, these pyridine derivatives are suitable precursors for subsequent palladium-catalyzed reactions. Suzuki couplings of the corresponding
The efficient preparation of four C-3-symmetric (star-shaped) pyridine and bipyridine derivatives is reported. The key steps are Suzuki couplings of 4-pyridyl nonaflates with 4-acetyl-phenylboronic acid followed by an acid-promoted cyclocondensation reaction converting the methyl ketone moiety into the central benzene ring of the target compounds. Based on STM studies at a graphite-solution interface the two-dimensional arrangements of the compounds are discussed, showing the influence of the pyridine substitution pattern.