Improved method for the synthesis of permethrin
AssigneeBiophore India Pharmaceuticals PVT. Ltd.
InventorsMANIK REDDY PULLAGURLA, MECHERIL VALSAN NANDA KUMAR, Madhusudhana Rao VELIGETLA, JAGADEESH BABU RANGISETTY
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Abstract
The present invention describes an improved method for the synthesis of substantially pure Permethrin (1) having purity greater than 99.5% by Gas Chromatography (GC). The invention also relates to a purification process of Permethrin by recrystallization from methanol-water mixture.
Claims7
A process for preparation of substantially pure pharmaceutical grade Permethrin whose purity is greater than 99.5% by blending Permethrin with varied isomeric ratio of cis:trans with trans Permethrin, wherein the weight of the two compounds to be blended is calculated as per the formula:
- [
- (
- Product
-
-
- A
-
-
- weight
-
-
- in
-
-
- g
- )
- ×
- (
- Trans
-
-
- ratio
-
-
- of
-
-
- A
- )
- ]
- +
- [
- (
- Product
-
-
- B
-
-
- weight
-
-
- in
-
-
- g
- )
- ×
- (
- Trans
-
-
- ratio
-
-
- of
-
-
- B
- )
- ]
- [
- (
- Product
-
-
- A
-
-
- weight
- +
- Product
-
-
- B
-
-
- weight
- )
- ]
- wherein, Product A is Permethrin with varied isomeric ratio and Product B is Permethrin.
A process for preparation of substantially pure Permethrin with greater than 99.5% purity comprising the steps of:
- I. Coupling of 3-phenoxybenzyl alcohol with 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarbonyl chloride, in a suitable solvent to yield Permethrin
- II. Purifying the Permethrin obtained in step I by recrystallizing in methanol and water mixture to obtain a substantially pure Permethrin
- III. Blending pure Permethrin of step II with pure trans to obtain substantially pure Permethrin with desired isomeric ratio.
A process for the purification of Permethrin comprising recrystallizing it from a mixture of methanol and water.
Dependencies are inferred from the claim text.