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US 6,639,079 B1Granted
Chemical process
AssigneeSyngenta Limited
InventorsStephen Martin Brown, Martin Charles Bowden
Life of this patent
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Abstract
A process for the preparation of 3,5-dichloropyridine comprising reacting a trichloropyridine, a tetrachloropyridine or pentachloropyridine with zinc metal, in the presence of an acidic compound and at a temperature in the range 50-120° C.
Claims4
A process for preparing 3,5-dichloropyridine comprising:
- a) reacting acrylonitrile with anhydrous chloral in the presence of copper (I) chloride at a temperature in the range 100-200° C., to form 2,3,5-trichloropyridine;
- and,
- b) reacting the 2,3,5-trichloropyridine so formed with zinc metal, in the presence of an acidic compound and at a temperature in the range 50-120° C.
Dependencies are inferred from the claim text.