Ulipristal Acetate Synthesis via Methyllithium Reaction
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Solution Overview
Problem
Current industrial-scale synthesis processes for progesterone derivatives like ulipristal acetate are inefficient and environmentally unfriendly, with low yields and excessive steps, making them unsuitable for large-scale production.
Innovation Solution
A new synthesis process involving the reaction of compound II with methyllithium in the presence of tetraalkyl ethylenediamine at controlled temperatures, followed by acid treatment and acetylation, reduces the number of steps and improves yield, using more environmentally friendly solvents and conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional multi-step synthesis processes are used for ulipristal acetate, then the product can be obtained, but the yield is low and the number of steps is excessive
Solution Approach 1:
The synthesis process is divided into distinct functional segments: oxidation step, protection step, Grignard reaction step, and deprotection step. Each segment performs a specific transformation, allowing for optimized reaction conditions and intermediate isolation, thereby improving overall yield while reducing unnecessary steps.
Solution Approach 2:
The 3-keto group is protected as an ethylenedioxy ketal before the Grignard reaction, and the 17-keto group is protected as a dimethyl acetal beforehand. These preliminary protection actions prevent unwanted side reactions during the carbon-carbon bond formation, ensuring higher selectivity and yield in the main transformation step.
2Object-affected harmful factors
If conventional synthesis processes are used, then the reaction can proceed, but environmental friendliness is poor
Solution Approach 1:
The oxidation step uses sodium periodate as a milder, more selective oxidant compared to conventional strong oxidizing agents. The deprotection step employs aqueous acid conditions that are easier to handle and dispose of than harsher alternatives. These parameter changes reduce environmental impact while maintaining high reaction efficiency and yield.
3Ease of manufacture
If conventional synthesis routes are used, then the product can be synthesized, but the process is not economical for industrial scale
Solution Approach 1:
The protection of the 3-keto and 17-keto groups are performed in a single combined acetalization step using ethylene glycol under acidic conditions, rather than as separate operations. This merging of steps reduces overall synthesis time and operational complexity, making the process more economical for industrial scale 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
The process achieves a higher yield in fewer steps, making it more economical and environmentally friendly compared to existing methods, suitable for industrial-scale production of progesterone derivatives such as ulipristal acetate.
Implementation Method 1
the reaction of compound II with methyllithium in the presence of tetraalkyl ethylenediamine
Implementation Method 2
followed by acid treatment
Implementation Method 3
and acetylation
Data Source
AI summary
The present invention relates to a new process for the synthesis of compounds of formula (I) (wherein the meaning of R is dimethylamino or acetyl group) using the compound of formula (II) (wherein the meaning of R is dimethylamino or 2-methyl-1,3-dioxolan-2-yl group) as starting material, as well as to the intermediate of the process.