Ribociclib Intermediate Synthesis Without Heavy-Metal Contamination
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Solution Overview
Problem
Existing synthetic routes for Ribociclib and its intermediates are limited by the need for costly and hazardous metals, high reaction temperatures, and low yields, while known physiologically acceptable salts lack desirable properties for pharmaceutical applications.
Innovation Solution
A process using potassium tert-butanolate (KOtBu) as a base in mild conditions with specific stoichiometric ratios and solvents like toluene or THF, avoiding heavy metals and costly reagents, achieves yields of over 70% without requiring silica gel chromatography, and allows for the production of novel physiologically acceptable salts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper-catalyzed Ullmann-Goldberg amination reactions are used, then C-N bond formation can be achieved, but heavy metal contamination and high reaction temperatures are required
Solution Approach 1:
The patent removes copper catalyst from the reaction system entirely, replacing it with a palladium-catalyzed Buchwald-Hartwig amination that uses a different mechanism avoiding copper contamination while maintaining C-N bond formation efficiency
Solution Approach 2:
The patent changes the reaction parameters by using palladium instead of copper, and employs a different ligand system (BINAP) with controlled stoichiometry (0.05-0.20 equivalents) to achieve the same transformation under cleaner conditions
2Temperature
If palladium-catalyzed Buchwald-Hartwig amination reactions are used, then mild reaction conditions can be achieved, but costly palladium reagents and ligands are required
Solution Approach 1:
The patent optimizes the palladium loading to 0.05-0.20 equivalents and uses BINAP ligand at 0.10-0.40 equivalents, balancing mild reaction conditions with cost considerations through precise stoichiometric control
Solution Approach 2:
The patent employs a composite catalytic system combining palladium with BINAP ligand, creating a synergistic catalyst that operates effectively at low loadings and moderate temperatures, reducing both cost and energy requirements
3Object-affected harmful factors
If aromatic nucleophilic substitution is used, then reaction can proceed without heavy metals, but strong non-nucleophilic bases are required
Solution Approach 1:
The patent introduces a silyl protecting group (TBS) as an intermediary that enables the use of milder bases by protecting the alcohol functionality, allowing aromatic nucleophilic substitution to proceed without requiring strong non-nucleophilic bases
4Manufacturing precision
If silica gel chromatography is used for purification, then product purity can be achieved, but production time and costs increase
Solution Approach 1:
The patent removes silica gel chromatography from the purification process by designing a reaction pathway that produces minimal side products and allows for simpler filtration and washing procedures to achieve sufficient purity
Solution Approach 2:
The reaction conditions are optimized to be self-purifying, where the byproducts and excess reagents can be removed by simple filtration and washing, eliminating the need for time-consuming chromatographic purification
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
The process provides Ribociclib intermediates and salts with high yields and improved properties, reducing production costs and environmental impact, while ensuring the final drug is free of heavy metals and facilitating easy isolation and purification.
Implementation Method 1
aromatic nucleophilic substitution (e.g. US 2018/16054443 A, WO 2019/142206 A1, WO 2019/150181 A1)
Data Source
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AI summary
The invention relates to the synthesis of Ribociclib, and in particular to the synthesis of a 4-[6-[[7-cyclopentyl-6-(dimethylcarbamoyl)pyrrolo[2,3-d]pyrimidin-2-yl]amino]-3-pyridyl]-piperazine-1-carboxylate, which is an important intermediate in the synthesis of Ribociclib. Further, the invention relates to novel physiologically acceptable salts of Ribociclib.