Process for the preparation of 2-halogenopyridinealdehydes and novel 2-halogenopyridinealdehydes

摘要

The reaction of cyanoolefins, aminocarbonylolefins or hydroxyiminoolefins with a Vilsmeier reagent leads to 2-halogenopyridines which bear aldehyde groups in the 3 and/or 5 position. These pyridinealdehydes are valuable intermediates for the preparation of pharmaceuticals and crop protection agents.