Condensed Imidazolo Derivative Synthesis via Salt-Mediated Cyclization
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Solution Overview
Problem
Current methods for producing 4-(6,7-dihydro-5H-pyrrolo[1,2-c]imidazole-5-yl)-3-fluorobenzonitrile are not ideal for industrial scale-up due to the need for additional synthetic steps and the formation of side products, which complicates the production of high yields and purity.
Innovation Solution
A process involving the reaction of a compound with a base in the presence of an alkaline- or alkaline earth metal salt to suppress the elimination of a leaving group and reduce the formation of side products, allowing for high-yield and high-purity production of 4-(6,7-dihydro-5H-pyrrolo[1,2-c]imidazole-5-yl)-3-fluorobenzonitrile in a single step.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the known process with auxiliary ester moiety is used, then cyclization can be achieved, but the number of synthetic steps increases
Solution Approach 1:
The invention removes the auxiliary ester moiety from the synthetic pathway entirely. Instead of installing the ester group to activate the benzylic position and then removing it later, the process directly cyclizes the compound of formula VI using a base, eliminating the need for the auxiliary activating group and its subsequent removal steps.
Solution Approach 2:
The invention performs the cyclization reaction directly on the compound of formula VI without preliminary activation. The base is applied directly to the chloroethyl compound to induce intramolecular cyclization, bypassing the need for prior esterification to activate the benzylic position.
2Productivity
If direct cyclization of compound VI with base is attempted, then the number of steps is reduced, but elimination of HCl occurs instead of cyclization
Solution Approach 1:
The invention changes the reaction parameters by selecting specific bases (such as alkali metal hydroxides, carbonates, or bicarbonates) and controlling the reaction conditions (temperature, solvent, stoichiometry) to favor cyclization over elimination. These parameter adjustments enable the direct cyclization of compound VI to proceed successfully without HCl elimination.
3Reliability
If auxiliary ester moiety is introduced, then cyclization can proceed, but additional steps for introduction and removal are required
Solution Approach 1:
The invention extracts the auxiliary ester moiety from the synthetic pathway. The process achieves successful cyclization without introducing the ester activating group, thereby eliminating both the introduction step and the subsequent removal step that would otherwise be required.
4Quantity of substance
If the known process is used, then the compound can be produced, but side products are formed reducing purity
Solution Approach 1:
The invention optimizes reaction parameters including base selection, temperature control, and reaction time to minimize side product formation. By carefully controlling these parameters during the direct cyclization of compound VI, the process achieves high product purity while maintaining efficient production.
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 approach results in reproducible high yields and high purity of the compound, with reduced levels of side products, making it suitable for industrial scale-up and pharmaceutical applications.
Implementation Method 1
the presence of an alkaline- or alkaline earth metal salt suppressed elimination of the leaving group from the compound of formula VII when reacting the compound of formula VII with a base
Implementation Method 2
The inventors have further found that the use of an alkaline- or alkaline earth metal salt suppressed the formation of 3-(2-(1H-imidazol-5-yl)ethyl)-2-(4-(6,7-dihydro-5H-pyrrolo[1,2-c]imidazol-5-yl)-3-fluorophenyl)-1H-indole-6-carbonitrile (formula (VIII))
Implementation Method 3
reacting a compound of formula VII with a base in the presence of an alkaline- or alkaline earth metal salt (MX in scheme 1) to form the compound of formula I
Data Source
AI summary
The present invention relates to a process for providing the compound of formula I, comprising the step of reacting a compound of formula VII with a base in the presence of an alkaline- or alkaline earth metal salt (MX), wherein LG is a leaving group. The presence of an alkaline- or alkaline earth metal salt was surprisingly found to render said reaction highly reliable in terms of the yield and purity of the compound of formula I obtained. In a further aspect, the present invention relates to the compound of formula I, having less than an amount of 1.50% or less than an amount of 1.25% or less than an amount of 1.00% or less than an amount of 0.75% or less than an amount of 0.50% or less than an amount of 0.25% or less than an amount of 0.10% of the compound of formula VIII.