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US 7,126,005 B2Granted
Process for preparing florfenicol
AssigneeAurobindo Pharma Ltd
InventorsVijay Kumar Handa, Arun Kumar Gupta, Meenakshisunderam Sivakumaran
Life of this patent
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Abstract
The present invention is directed to a new process of preparing highly pure Florfenicol. The invention is further directed to new oxazolidine derivatives useful in making Florfenicol and processes of making these derivatives. Examples of such intermediates include (4R,5R)-3-acetyl-2,2-dimethyl-4-hydroxymethyl-5-[4-(methylsulfonyl)phenyl]-1,3-oxazolidine; and (4S,5R)-3-acetyl-2,2-dimethyl-4-fluoromethyl-5-[4-(methylsulfonyl)phenyl]-1,3-oxazolidine.
Claims21
A process of preparing a compound of Formula VII:
- wherein R1 is a methylthio, methylsulfoxy, methylsulfonyl or nitro group, the process comprising the steps of:
- reacting the compound of Formula VIII
- with an agent in the presence of a first organic base and a first organic solvent to produce a compound of Formula IX
- wherein R2 is an alkyl, haloalkyl, cycloalkyl, alkenyl, alkynyl, alkoxy, aralkyl, aralkenyl, aryl or aromatic heterocyclic group;
- and
- R3 is a hydrogen, alkyl, haloalkyl, cycloalkyl, alkenyl, alkynyl, alkoxy, aralkyl, aralkenyl, aryl or aromatic heterocyclic group;
- converting the compound of Formula IX to a compound of Formula X:
- wherein R4 is a hydrogen, alkyl, haloalkyl, cycloalkyl, phenyl or phenylalkyl group, where the phenyl ring may be substituted by one or two halogen, alkyl, alkoxy or nitro groups, by reacting the compound of Formula IX with R4COCl in the presence of a second organic base in a second organic solvent to produce the compound of Formula X;
- fluorinating the compound of Formula X with a fluorinating agent in the presence of a third organic solvent to obtain the compound of Formula XI
- and
- further processing the compound of Formula XI to obtain the compound of Formula VII.
8 more elements
Dependencies are inferred from the claim text.