Process for preparing halogenated pyridine derivatives

A process for preparing a compound of formula (II)

• wherein
• Q and W are each independently halogen, and
• Y is halogen, CO2R1 or NO2, where R1 is (C1-C6)-alkyl or (C1-C6)-haloalkyl,
• wherein, in a first process step a), a compound of formula (I)
• wherein W and Y each have the definitions given above,
• is reacted with an organozinc base of structure (NR3R4)—Zn—R2 or (NR3R4)2—Zn wherein
• R2 is halogen or O-pivaloyl and
• R3 and R4 together form a —(CH2)4—, —(CH2)5— or —(CH2)2O(CH2)2— group, where each of these groups may optionally be substituted by 1, 2, 3 or 4 R5 radicals and R5 is selected from the group consisting of methyl, ethyl, n-propyl and i-propyl,
• to give a compound of formula (IIIa) or formula (IIIb)
• wherein W, Y and R2 each have the definitions given above,
• wherein the step a) is conducted at a temperature between 30° C. and 80° C.,
• and this compound of formula (IIIa) or (IIIb) is reacted in a second process step b) with a compound of the structure Q-X wherein X is halogen and Q has the abovementioned definition to give the compound of formula (II).