Stereoselective Heteroarylalkylsulfanyl Pyrimidines at Scale
Solution Overview
Problem
Existing methods for producing chiral pyrimidines with high chiral purity face challenges in scalability and yield, particularly in setting the stereochemistry of the second stereocentre, leading to the need for inefficient purification steps like recrystallization that reduce process efficiency.
Innovation Solution
A process involving the formation of a (hetero)arylalkylsulfanylpyrimidine ester under specific reaction conditions and subsequent reaction with a pyrimidine thiolate anion, allowing for the production of compounds with high chiral purity without additional recrystallization steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chiral HPLC purification is used to achieve high chiral purity, then chiral purity is improved, but scalability and productivity deteriorate
Solution Approach 1:
The invention introduces a chiral auxiliary in the form of a chiral sulfonate ester (e.g., (R)- or (S)-1-phenylethyl sulfonate) during the synthesis of the pyrimidine compound. This preliminary chiral induction allows the reaction to proceed with inherent stereoselectivity, producing the desired enantiomer preferentially without requiring subsequent chiral HPLC purification, thus enabling both high chiral purity and scalability
2Manufacturing precision
If successive recrystallisation steps are used to improve chiral purity, then chiral purity is improved, but yield and process efficiency deteriorate
Solution Approach 1:
The invention changes the reaction parameters by using a chiral sulfonate ester as a chiral auxiliary during the nucleophilic substitution reaction. This parameter change induces stereoselectivity at the transition state, allowing the reaction to produce the desired enantiomer with high chiral purity in a single step, eliminating the need for multiple recrystallisation steps and associated yield losses
3Manufacturing precision
If conventional synthesis routes are used to set stereochemistry, then chiral purity can be achieved, but additional purification steps are required
Solution Approach 1:
The invention uses a chiral sulfonate ester (e.g., (R)- or (S)-1-phenylethyl sulfonate) as a chiral intermediary or auxiliary during the synthesis. This chiral auxiliary temporarily imparts chirality to the reaction system, guiding the formation of the desired stereocenter. After the reaction, the chiral auxiliary can be removed or remains as a removable group, having fulfilled its purpose of enabling stereoselective synthesis without requiring additional complex purification steps
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 method enables the production of chiral pyrimidines with excellent chiral purity and yield, suitable for large-scale synthesis of pharmaceutically-active compounds.
Implementation Method 1
reacting a compound of formula III with a suitable sulfonating agent in the presence of a suitable base B1 and a suitable solvent (S1)
Implementation Method 2
in the presence of a suitable base B1 and a suitable solvent (S1) in which the salt formed between B1 and the leaving group of the sulfonating agent is insoluble
Implementation Method 3
reacting the compound of formula II, with a compound of formula IV
Data Source
AI summary
Described herein is a process for the preparation of a compound of Formula I,wherein R1 and R2 each have the meanings provided in the description. Also described is a process for the preparation of pharmaceutically-active compounds including the process for the preparation of compounds of Formula I.