Substituted pyridines

Details Substituted pyridines Substituted pyridines

2006-08-07

2009-02-03

Aulakh, Charanjit S (Department: 1625)

Organic compounds -- part of the class 532-570 series

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

C544S065000

Reexamination Certificate

active

07485725

ABSTRACT:
A class of 2,4-; 2,3,4-; 2,4,6-; 2,3,4,5,6-substituted pyridines is provided which include novel compounds. The substitutions are achieved according to methods disclosed herein in which a metallated pyridine is reacted with an electrophile. Suitable electrophiles include CO2, SO2, dialkylcarbonates, ureas, formamides, amides, carboxylic acid esters, mono- and dihaloalkyls, halogens such as chlorine, fluorine, bromine, and iodine, metallic salts, sulfones, sulfonyls, aldehydes, ketones, anhydrides, nitriles, and electrophilic boron compounds including, but not limited to, boron trialkoxides and boron trihalides. The subject invention more specifically discloses a process for the synthesis of 2,6-difluoropyridin-4-ylboronic acid which comprises: (1) reacting 2,4,6-trifluoropyridine with hydrazine monohydrate to produce 2,6-difluoro-4-hydrazinopyridine, (2) reacting the 2,6-difluoro-4-hydrazinopyridine with elemental bromine to produce 4-bromo-2,6-difluoropyridine, and (3) reacting the 4-bromo-2,6-difluoropyridine with an organolithium compound and a borate at a temperature of less than 0° C. to produce the 2,6-difluoropyridin-4-ylboronic acid, wherein said process is conducted in an organic solvent.

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