Synthesis of 2-Alkoxy-5-(Pyridin-2-yl)pyridine via Moderate-Temperature Catalysis
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Solution Overview
Problem
Existing methods for synthesizing 2-alkoxy-5-(pyridin-2-yl)pyridine, an intermediate for Perampanel, face drawbacks such as the need for cryogenic conditions, use of inconvenient reagents like 2-Bromopyridine, and scarce atom-economy due to the use of high molecular weight leaving groups.
Innovation Solution
A process involving the conversion of 5-halogen-2-alkoxypyridine to a Grignard reagent or its lithium chloride complex, followed by reaction with 2-halogenpyridine using a metallic complex catalyst at moderate temperatures, eliminating the need for cryogenic equipment and allowing for a more atom-economical synthesis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cryogenic conditions (T=-78°C) and special equipment are used for synthesis, then the reaction can proceed with certain reagents, but the device complexity and operational convenience deteriorate
Solution Approach 1:
The patent changes the temperature parameter from cryogenic conditions (-78°C) to moderate temperatures (25-60°C), eliminating the need for special cryogenic equipment while maintaining reaction effectiveness through modified reagent systems
Solution Approach 2:
The patent replaces expensive, specialized cryogenic equipment with simple, readily available laboratory equipment that can operate at moderate temperatures, making the process more accessible and easier to implement
2Reliability
If 2-Bromopyridine is used as reagent, then the synthesis can proceed, but the loss of substance and waste generation worsen compared to 2-chloropyridine
Solution Approach 1:
The patent uses 2-chloropyridine as a substitute for 2-bromopyridine, creating a chemically analogous reagent that produces less waste and is more environmentally friendly while maintaining the essential synthetic function
Solution Approach 2:
The patent changes the halogen parameter from bromine to chlorine in the pyridine reagent, which reduces the molecular weight and environmental impact while preserving the reactivity needed for the synthesis
3Reliability
If high molecular weight benzenesulfonyl pyridine is used, then the synthesis can proceed, but the atom-economy deteriorates
Solution Approach 1:
The patent extracts and removes the bulky benzenesulfonyl protecting group from the synthetic pathway, using simpler reagents that directly provide the desired product without requiring subsequent removal of large protecting groups, thereby improving atom-economy
Solution Approach 2:
The patent replaces high molecular weight benzenesulfonyl pyridine with lighter, more efficient reagents that minimize waste and improve atom-economy while maintaining synthetic effectiveness
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 purity of 2-alkoxy-5-(pyridin-2-yl)pyridine while avoiding the use of special equipment and large leaving groups, offering improved atom-economy and operational convenience.
Implementation Method 1
reaction of the compound obtained in the step (a) with a 2-halogenpyridine or 2-pseudohalogenpyridine of formula (II) in which X1 is chosen between chlorine, bromine, iodine, triflate, nonaflate, mesylate, tosylate and besylate or -O(C=O)NR' 2 wherein R' is a linear or branched C 1 -C 4 alkyl group or is phenyl or benzyl, in which step (b) is catalyzed by a metallic complex of palladium, nickel, iron or cobalt
Data Source
AI summary
The present invention relates to a process for synthesising 2-alkoxy-5-(pyridin-2-yl)pyridine which is an intermediate of the synthesis of the active substance Perampenel.