Topramezone Form I Crystallization Stability

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Solution Overview

Problem

The production of topramezone crystalline forms often results in complex mixtures of various crystal modifications, leading to unsatisfactory stability in formulations, with existing solid forms exhibiting issues such as needle-shaped crystals, low stability against phase transformation, and poor handling characteristics.

Innovation Solution

A stable, high-purity crystalline modification of topramezone, referred to as Form I, is obtained through specific processes, which includes crystallization from organic solvents like alcohols and alkanediols, resulting in compact block-shaped crystals that are easier to filter and handle, with enhanced stability and purity levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional crystallization processes are used to produce topramezone, then crystalline solid forms are obtained, but complex mixtures of various crystal modifications result, leading to poor formulation stability

Engineering Contradiction:
Improveformulation stabilityVSAvoidcrystal form purity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by systematically varying crystallization conditions (temperature, solvent type, concentration, cooling rate) to selectively obtain Form I crystals. By controlling these parameters, the process achieves high purity (>90%) Form I crystals with superior formulation stability, resolving the contradiction between obtaining pure crystal forms and ensuring formulation stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses specific solvent systems as intermediaries to facilitate the formation of Form I crystals. By selecting appropriate solvents and solvent mixtures as intermediaries in the crystallization process, the invention achieves both high crystal form purity and excellent formulation stability, overcoming the limitations of conventional direct crystallization methods.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If existing solid forms of topramezone are used, then production is achieved, but needle-shaped crystals result, which are difficult to filter and handle

Engineering Contradiction:
Improvehandling characteristicsVSAvoidcrystal morphology
Core Design Contradiction:
Ease of operationVSShape

Solution Approach 1:

The patent employs parameter changes in the crystallization process (temperature profile, solvent composition, agitation conditions) to control crystal morphology. These parameter adjustments transform the needle-shaped crystals into compact block-shaped Form I crystals that are easy to filter and handle, while maintaining high purity and formulation stability.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If conventional crystallization is applied to topramezone, then solid forms are produced, but low stability against phase transformation occurs

Engineering Contradiction:
Improvephase transformation stabilityVSAvoidcrystal form stability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent utilizes specific solvent systems as intermediaries that promote the formation of thermodynamically stable Form I crystals. These solvent intermediaries enable the production of crystals with high phase transformation stability and long-term reliability, overcoming the instability issues of conventional topramezone solid forms.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Form I exhibits increased stability and improved handling properties, leading to more stable formulations with higher purity levels, specifically achieving at least 90% by weight, and is identified using X-ray powder diffractometry with characteristic diffraction patterns.

Implementation Method 1

crystallization from organic solvents like alcohols and alkanediols, resulting in compact block-shaped crystals

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Implementation Method 2

identified using X-ray powder diffractometry with characteristic diffraction patterns

Methodology Applied
Scientific EffectX-ray diffraction: X-Ray

Implementation Method 3

An X-ray powder diffractogram recorded at 30 ° C using Cu-Kα radiation (1.54178 Å) shows at least 5, often at least 6, in particular at least 7, and especially all of those in the following Table 1 as 2θ values

Methodology Applied
Scientific EffectDiffraction: Diffraction

Data Source

PatentEP2173742B1Crystalline form of [3-(4,5-dihydro-3-isoxazolyl)-2-methyl-4-(methylsulfonyl)phenyl]-(5-hydroxy-1-methyl-1h-pyrazol-4-yl)methanone
Publication Date: 2011.11.23 BASF SE
  • EP2173742B1 patent drawingFigure 1~2
  • EP2173742B1 patent drawingFigure 3~4
  • EP2173742B1 patent drawingFigure 5~6

AI summary

The present invention relates to crystalline forms of [3-(4,5-dihydro-3-isoxazolyl)- 2-methyl-4-(methylsulfonyl)phenyl]-(5-hydroxy-1 -methyl-1H-pyrazol-4-yl)methanone, which is also known by the common name topramezone. The invention also relates to a method for the production of these crystalline forms, and to formulations which contain one of these crystalline forms of topramezone for protecting plants.