Bipyrazole Benzamide Synthesis via Crystallization Purification
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Solution Overview
Problem
Existing methods for synthesizing 2-chloro-N-(1-cyanocyclopropyl)-5-[2′-methyl-5′-(pentafluoroethyl)-4′-(trifluoromethyl)-2′H-1,3′-bipyrazol-4-yl]benzamide suffer from low overall yield and high cost due to the use of highly fluorinated raw materials, making commercial production unfavorable.
Innovation Solution
A method involving the reaction of compounds of formula (VI) with formula (VII) in the presence of a base and catalyst, followed by purification through crystallization from aromatic hydrocarbons, enhances yield and purity, allowing industrial-scale production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If column chromatography on silica gel is used for purification, then purity is improved, but productivity deteriorates due to low overall yield of only approx. 49%
Solution Approach 1:
The patent changes the purification method from column chromatography to crystallization from aromatic hydrocarbons, fundamentally altering the purification parameters to achieve both high purity and high yield simultaneously
Solution Approach 2:
The patent replaces the expensive and time-consuming column chromatography process with a simpler, more economical crystallization process using aromatic hydrocarbons, making the purification step more efficient and cost-effective
2Manufacturing precision
If highly fluorinated raw materials are used, then the desired compound structure is obtained, but cost deteriorates due to high purchase price
Solution Approach 1:
The patent divides the synthesis into two stages: first preparing the highly fluorinated intermediate (formula VI) which can be stored, then reacting it with compound (VII) to form the final product, allowing better cost management and material utilization
Solution Approach 2:
The patent performs preliminary preparation of the highly fluorinated pyrazole compound (formula VI) in advance, which can be stored and then used in the coupling reaction, optimizing both cost and process efficiency
3Manufacturing precision
If structural unit of formula II is prepared with low yield of approx. 24%, then commercial production becomes unfavorable, but the desired fluorinated structure is obtained
Solution Approach 1:
The patent changes the synthesis route by directly coupling compound (VI) with compound (VII) in a Pd-catalyzed reaction, fundamentally improving the yield from 24% to approximately 90% or higher
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves a substantial increase in yield and purity, reducing impurities like amide, bispyrazoloboronic ester, and palladium content to less than 2% by weight, suitable for veterinary medicaments.
Implementation Method 1
by reacting compounds of the formula (VI) with compounds of the formula (VII) in the presence of a base and a catalyst
Implementation Method 2
by reacting compounds of the formula (VI) with compounds of the formula (VII) in the presence of a base and a catalyst
Implementation Method 3
A method for purifying the compound of the formula I, wherein this is crystallized from an aromatic hydrocarbon
Data Source
AI summary
The present invention relates to a method for preparing 2-chloro-N-(1-cyanocyclopropyl)-5-[2′-methyl-5′-(pentafluoroethyl)-4′-(trifluoromethyl)-2′H-1,3′-bipyrazol-4-yl]benzamide, i.e. the compound of the formula (I) and to a method for purifying the compound of the formula I. The present invention additionally relates to new crystal forms of the compound of the formula I.