CA2521695C — Method for producing 3-substituted 2-chloro-5-fluoro-pyridine or its salt

USPTO Abstract

A method for producing a 3-substituted 2-chloro-5-fluoro-pyridine or its salt in high yield from a readily available material through a short process under mild reaction conditions using a reagent which is easy for handling and simple in the reaction operation. The method comprising selectively reducing a chlorine atom at the 6-position of the following compound (1) or its salt, to obtain the following compound of formula (2) or its salt. The compound of formula (2) or its salt may be further substituted to obtain the following compound (4) or its salt. Here, Z1 is -CO2R1, etc., Z2 is a group different from Z1 and is -CO2R5, etc. R1 and R5 are independently an alkyl group, an alkenyl group, an aryl group, an aralkyl group or cycloalkyl group, or R1 is hydrogen. (see formula 1) (see formula 2) (see formula 4)