6-Aryloxyquinoline Synthesis via Regioselective Cyclization
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Solution Overview
Problem
Current processes for producing 6-aryloxyquinoline derivatives have low yields and require complex separation steps, making them unsuitable for commercial-scale production, especially when introducing substituents at the 5- and 7-positions, which further reduces efficiency.
Innovation Solution
A process involving the use of 4-aryloxyanthranilic acid derivatives to improve the efficiency of quinoline ring construction and allow for regioselective introduction of substituents, including a cyclization reaction and condensation steps, to produce 6-aryloxyquinoline derivatives with high yields and purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a 4-aryloxyaniline derivative is reacted with a β-ketocarboxylic acid ester to produce a 6-aryloxyquinoline derivative, then the quinoline derivative can be obtained, but the yield in the cyclization reaction is low to medium
Solution Approach 1:
The patent changes the chemical parameters of the reaction by using a different starting material (4-aryloxyanthranilic acid derivative instead of 4-aryloxyaniline derivative) and a different reaction pathway (cyclization followed by condensation instead of direct cyclization), which significantly improves the yield from low to medium to high levels
Solution Approach 2:
The patent divides the synthesis process into two separate steps: first forming the quinolone derivative through cyclization, then converting it to the final quinoline derivative through condensation. This segmentation allows each step to be optimized independently, achieving high overall yield
2Adaptability or versatility
If a substituent is introduced into the 5- or 7-position of the quinoline derivative, then the desired substituted product can be obtained, but a mixture of position isomers is produced requiring complicated separation steps
Solution Approach 1:
The patent introduces the substituent at the desired position (5- or 7-) during the initial cyclization step when the aromatic ring is being formed, rather than attempting to introduce it later. This preliminary action ensures regioselectivity and eliminates the formation of position isomers, making separation unnecessary
Solution Approach 2:
The patent achieves regioselective substitution by controlling the local chemical environment during cyclization, where the substituent is introduced at a specific position on the aromatic ring due to the directed nature of the reaction mechanism, preventing isomer formation
3Productivity
If the current production process is used, then 6-aryloxyquinoline derivatives can be produced, but the process is not suitable for commercial-scale production due to low yield and complex separation requirements
Solution Approach 1:
The patent fundamentally changes the production parameters by using 4-aryloxyanthranilic acid derivatives as starting materials and implementing a two-step process with optimized conditions, achieving high yields (70-95%) that make the process economically viable for commercial-scale production
Solution Approach 2:
The patent extracts and eliminates the problematic separation step from the production process by ensuring regioselective substitution occurs during the initial cyclization, so that only the desired position isomer is formed and no separation is needed
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 process achieves high yields and eliminates the need for complicated purification steps, enabling the efficient production of 6-aryloxyquinoline derivatives with desired substituents, making it industrially advantageous for commercial production.
Implementation Method 1
a cyclization reaction step (C) of reacting an anthranilic acid derivative represented by general formula (1) with a ketone represented by general formula (2) in the presence of an acid to obtain a quinolone derivative of general formula (3)
Implementation Method 2
a condensation reaction step (D) of reacting the quinolone derivative of general formula (3) with a halogen compound represented by general formula (4) or an acid anhydride represented by general formula (5) to obtain a quinoline derivative represented by general formula (6)
Data Source
AI summary
Disclosed is a process for producing 6-aryloxyquinoline derivatives useful as insecticides or fungicides for agricultural and horticultural use. The process comprises a cyclization reaction step of reacting an anthranilic acid derivative represented by general formula (1) with a kenone in the presence of an acid to obtain a quinolone derivative and a condensation reaction step of reacting the quinolone derivative with a halogen compound or an acid anhydride to obtain a quinoline derivative.