2-Cyanophenylboronic Acid Synthesis via Mild-Temperature Grignard
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Solution Overview
Problem
Current synthesis processes for 2-cyanophenylboronic acid and its esters, such as those used in producing Perampanel and E2040, face challenges including low molar yields, the need for cryogenic conditions, and the presence of impurities, making them inefficient for industrial-scale production.
Innovation Solution
A process involving the conversion of 2-halogenbenzonitrile to a lithium chloride complex Grignard reagent, followed by reaction with trimethoxyborane, and subsequent acid hydrolysis, which allows for a one-pot reaction at mild temperatures (0-5°C) to achieve higher yields (80-85%) and improved purity (>98%) without the need for cryogenic equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the process described in US2009/0184289 is used to prepare 2-cyanophenylboronic acid, then the molar yield is improved (71%), but the process requires cryogenic conditions (T = -78°C) using special equipment and produces impurities
Solution Approach 1:
The invention changes the temperature parameter from cryogenic conditions (-78°C) to mild conditions (0-5°C), eliminating the need for specialized cryogenic equipment while maintaining high molar yield (80-85%). This parameter change resolves the contradiction between improved productivity and device complexity.
2Productivity
If the process described in US2009/0184289 is used to prepare 2-cyanophenylboronic acid, then the molar yield is improved (71%), but impurities are produced
Solution Approach 1:
The invention optimizes reaction parameters including temperature (0-5°C), reagent ratios, and reaction time to simultaneously achieve high molar yield (80-85%) and high product purity (>98%), eliminating the trade-off between productivity and manufacturing precision.
3Temperature
If the process described in Journal of Organometallic Chemistry (2002) is used to prepare the compound of formula (I), then the reaction can be carried out at higher temperature, but the molar yield is low (about 50%)
Solution Approach 1:
The invention identifies optimal temperature conditions (0-5°C) that balance reaction efficiency and yield, achieving high molar yield (80-85%) at mild temperatures without requiring cryogenic equipment, thus resolving the contradiction between temperature and 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 process significantly increases the molar yield and purity of 2-cyanophenylboronic acid and its esters, overcoming the limitations of existing methods by avoiding cryogenic conditions and achieving higher yields and better product stability, facilitating more efficient industrial production.
Implementation Method 1
conversion of a 2-halogenbenzonitrile of formula (IV) in a 2-cyanophenyl magnesium halide lithium chloride complex of formula (III)
Implementation Method 2
conversion of the compound obtained in step (a) to give the compound of formula (II)
Implementation Method 3
subsequent acid hydrolysis, which allows for a one-pot reaction
Data Source
Figure 1
AI summary
The present invention relates to a process for the synthesis of 2- cyanophenylboronic acid and the esters and salts thereof of formula (II), which are intermediates of the synthesis of active pharmaceutical ingredients such as Perampanel or E2040. formula (II): (II).