Pyrimidine Intermediate Synthesis for Macitentan
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Solution Overview
Problem
The existing methods for manufacturing macitentan, an endothelin receptor antagonist, face challenges in achieving sufficient purity due to the toxicity and high boiling point of ethylene glycol, which complicates purification processes, and the fragility of the sulfamide group, leading to undesired side reactions during tert-butyl group removal.
Innovation Solution
A new synthetic intermediate, compound I-2, is synthesized by reacting compound I-1 with 2-(tert-butoxy)ethanol in the presence of a base, followed by selective deprotection with TiCl4, allowing for high-purity production of compound I-3 without extensive purification steps, thereby facilitating the production of macitentan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ethylene glycol is used as solvent in the reaction to prepare compound I-3, then the reaction can proceed, but the purification becomes difficult due to high boiling point and toxicity
Solution Approach 1:
The patent changes the solvent parameter from ethylene glycol to 2-(tert-butoxy)ethanol, which has different physical properties including lower toxicity and more favorable purification characteristics. This parameter substitution resolves the contradiction by maintaining reaction feasibility while eliminating the harmful factors associated with ethylene glycol.
2Ease of manufacture
If conventional methods are used to remove tert-butyl group, then deprotection can occur, but the sulfamide group is cleaved causing undesired side reactions
Solution Approach 1:
The patent introduces TiCl4 as a selective intermediary reagent that mediates the deprotection of the tert-butyl group without affecting the sulfamide group. This intermediary enables the deprotection function while protecting the sulfamide group from cleavage, thus resolving the contradiction between deprotection capability and sulfamide group stability.
3Manufacturing precision
If numerous purification steps are undertaken to remove impurities, then sufficient purity can be achieved, but the process complexity and time increase
Solution Approach 1:
The patent employs preliminary action by selecting 2-(tert-butoxy)ethanol as solvent and using TiCl4 for selective deprotection, which prevents the formation of difficult-to-remove impurities from the outset. This preliminary strategic choice simplifies subsequent purification steps while maintaining high product purity, resolving the contradiction between manufacturing precision and device complexity.
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 enables the production of macitentan in high purity with simplified purification processes, avoiding the issues of ethylene glycol toxicity and sulfamide group fragility, and ensuring efficient conversion without harming the sulfamide group.
Implementation Method 1
selective deprotection with TiCl4, allowing for high-purity production of compound I-3 without extensive purification steps
Implementation Method 2
compound I-2, is synthesized by reacting compound I-1 with 2-(tert-butoxy)ethanol in the presence of a base
Data Source
AI summary
The present invention relates to a new synthetic intermediate, namely the compound of formula I-2or a salt thereof. Said compound of formula I-2 or its salt can be used to prepare the compound of formula I-3which is an important synthetic intermediate used in the preparation of macitentan.