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US 2010/0160641 A1Published application
Process for producing dihalopyridines
AssigneeJubilant Organosys Limited
InventorsGelebith H. MODI, Anil Kumar Tyagi, Ashutosh Agarwal, Hem Chandra, Nikhilesh Chandra Bhardwaj, Pradeep Kumar Verma
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Abstract
Disclosed herein an improved process for producing 2,3-dihalopyridine with high purity at industrial scale with minimum effluent.
Claims26
A process for preparing 2,3-dihalopyridine of formula (I),
- the process comprising:
- (a) halogenating 3-aminopyridine of formula (II) or salts thereof with halogenating agent in presence of ferric chloride to obtain crude 3-amino-2-halopyridine of formula (III);
- (b) diazotizing the 3-amino-2-halopyridine obtained in Step (a) with a nitrite salt to obtain diazonium salt;
- (c) reacting the diazonium salt with halo acid in presence of a copper (I) catalyst to form crude mass of 2,3-dihalopyridine of formula (I);
- (d) separating undesired products from the crude mass by employing water immiscible organic solvent;
- and
- (e) diluting the resultant mass employing water, followed by extraction employing water immiscible organic solvent to obtain 2,3-dihalopyridine of formula (I).
4 more elements
A process for preparing 2,3-dihalopyridine of formula (I),
- the process comprising:
- (a) halogenating 3-aminopyridine of formula (II) with halogenating agent in presence of ferric chloride, followed by filtration of the resultant mass at alkaline pH to obtain crude 3-amino-2-halopyridine of formula (III);
- (b) dissolving the crude 3-amino-2-halopyridine of formula (III) employing a water immiscible organic solvent followed by filtration of the resultant;
- (c) crystallizing the filtrate of step (b) to obtain pure 3-amino-2-halopyridine of formula (III);
- (d) diazotizing the 3-amino-2-halopyridine with a nitrite salt to obtain diazonium salt;
- (e) reacting the diazonium salt with halo acid in presence of a copper (I) catalyst to form crude mass of 2,3-dihalopyridine of formula (I);
- (f) separating undesired products from the crude mass by employing water immiscible organic solvent;
- and
- (g) diluting the resultant mass employing water, followed by extraction employing water immiscible organic solvent to obtain 2,3-dihalopyridine of formula (I).
6 more elements
Dependencies are inferred from the claim text.