Study On Preparation Technology Of Pyridine Borate Synthetic Block

Pyridylboronic acid compounds are important reagents in organic synthesis which can be reacted with aryl halide and palladium catalyst to product biaryl compounds by coupling reaction. In 1979, Japan Suzuki, of Hokkaido university professor first reported the Suzuki coupling reaction,and the reaction has been widely applied in organic synthesis. Arylboronic acid, as a substrate of the Suzuki coupling reaction, becomes a research hot spot in organic synthesis. The synthesis of pyridylboronic acid compounds are important and difficult in the synthesis of arylboronic acid.Our team are entrusted by Guizhou Wylton Jinglin Electronic Materials limited liability company to develop synthesis technology of 18 pyridylboronic acid compounds which are of market prospects. The synthesis technology of pyridylboronic acid compounds is studied in this paper. 18 target compounds which are included in 4-Pyridylboronic acid, 3-Pyridylboronic acid and 2-Pyridylboronic acid have been synthesised. All the target compounds are purified. A. 4-Pyridylboronic acid compounds: compounds A1-6 are synthesized from 2,3-dichloropyridine or 5-chloro-2,3-difluoropyridine and aliphatic amine by nucleophilic substitution, hydrogen reduction and electrophilic substitution.B. 3-Pyridylboronic acid compounds: with 2,5-dibromopyridine or 5-bromo-2-methylpyridine as starting materials, by the reaction of substitution, oxidation and electrophilic substitution to give the object compounds B1-11.C. 2-Pyridylboronic acid compound: compound C1 is synthesised from 2,6-dibromopyridine by 2 steps. The structures of the target compounds are fully characterized by MS and 1HNMR.