Quinoline Derivative Preparation via Salt Segmentation
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Solution Overview
Problem
Current methods for preparing quinoline derivatives, such as 8-chloro-N-(4-(trifluoromethoxy)phenyl)quinolin-2-amine, are costly, environmentally unfriendly due to the use of aniline derivatives in excess, and inefficient at industrial scale production, with issues related to solvent usage and product purity.
Innovation Solution
A method involving the preparation of the hydrochloride salt followed by conversion to the free base using an inexpensive base, eliminating the need for palladium catalysts and reducing solvent usage, with controlled steps to enhance purity, and incorporating a milling step to improve solubility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If aniline derivative is used in excess (2-3 equivalents) to serve as base for direct isolation of free base, then the coupling step can proceed without metal catalyst, but the cost increases and environmental friendliness deteriorates due to large excess reagent not completely consumed
Solution Approach 1:
The process is divided into two separate steps: first forming the hydrochloride salt with exactly 1 equivalent of aniline derivative, then converting to free base using a different base (NaOH or K2CO3). This segmentation allows each reagent to serve its specific function with optimal stoichiometry, eliminating the need for large excess of aniline derivative while maintaining process simplicity.
Solution Approach 2:
The patent combines the formation of hydrochloride salt and subsequent conversion to free base into a continuous process where the hydrochloride salt intermediate is directly treated with base without isolation. This merging maintains operational simplicity while using precise stoichiometry to reduce waste.
2Ease of operation
If aniline derivative in excess is used to neutralize hydrochloric acid, then the free base can be directly isolated, but the purification treatment requires large volumes of solvents which is detrimental to environment and increases cost
Solution Approach 1:
The patent changes the chemical form of the intermediate from requiring direct free base isolation to forming a stable hydrochloride salt that can be easily purified by filtration. This parameter change (from free base to salt form) enables simple solid-liquid separation without requiring large volumes of purification solvents, dramatically reducing solvent consumption and environmental impact.
3Productivity
If Buchwald-Hartwig amination with palladium acetate and Xantphos is used, then the coupling reaction can proceed efficiently, but the cost increases due to expensive metal catalyst
Solution Approach 1:
The patent replaces expensive palladium metal catalyst with a cheap, easily removable base-catalyzed system using NaOH or K2CO3. The inexpensive base serves its function and can be completely removed by filtration or washing, eliminating the need for expensive metal catalysts while maintaining coupling reaction efficiency and reducing production costs.
4Manufacturing precision
If hydrochloride salt isolation step is added before free base preparation, then the purity of compound increases, but the number of steps increases which may affect productivity
Solution Approach 1:
The patent performs preliminary formation of the hydrochloride salt which precipitates in high purity form, allowing simple filtration to remove impurities. This preliminary purification action enables the final free base product to achieve high purity without requiring additional expensive purification steps, balancing manufacturing precision with productivity.
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
This method results in a cost-effective, environmentally friendly, and scalable process for producing quinoline derivatives with improved solubility and purity, suitable for industrial production and pharmaceutical applications.
Implementation Method 1
reacting a compound of formula (II) with a compound of formula (III) to form the hydrochloride salt of the compound of formula (I)
Implementation Method 2
recovering the compound of formula (I) in the form of a free base through addition of a base
Data Source
AI summary
A method for preparing a compound of formula (I), a powder, and a pharmaceutical composition are disclosed. The method includes: (i) reacting a compound of formula (II) with a compound of formula (III), to form the hydrochloride salt of the compound of formula (I), and (ii) recovering the compound of formula (I) in the form of a free base through addition of a base. In step (i), the molar ratio of the compound of formula (II) to the compound of formula (III) is in a range of from 1.00:0.80 to 1.00:1.20, and no metal catalyst is present. A powder including the composition of formula (I) may be obtained by the method. The powder may have a particle size distribution with specific D50, D90 and/or D10 values. A pharmaceutical composition may include the powder and at least one pharmaceutically acceptable excipient.