Spirocyclic Ester Synthesis via One-Pot Solvent Swap
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current processes for preparing cis-alkoxy-substituted spirocyclic phenylacetylamino acid esters suffer from unsatisfactory yield and high operational costs, with solvents like chlorobenzene and dimethylacetamide posing environmental and disposal challenges.
Innovation Solution
A novel process using preferred solvents such as toluene or xylene, involving a series of reactions with bases and alcohols to achieve selective preparation of cis-alkoxy-substituted spirocyclic phenylacetylamino acid esters in higher purity and yield, without the need for intermediate isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If chlorobenzene and dimethylacetamide are used as solvents in the current process, then the extraction and esterification reactions can proceed, but the process incurs high disposal costs and environmental harm
Solution Approach 1:
The patent changes the solvent system from harmful chlorobenzene/DMAC to eco-friendly alternatives such as toluene, xylene, ethyl acetate, or their mixtures with water. This parameter change maintains process feasibility while eliminating the environmental harm and high disposal costs associated with the original solvents
Solution Approach 2:
The patent employs solvents that are easier and cheaper to dispose of environmentally. The new solvent system allows for simpler waste treatment and reduces disposal costs compared to the persistent and harmful chlorobenzene and DMAC
2Productivity
If the current extraction and esterification process is used, then cis-alkoxy-substituted spirocyclic phenylacetylamino acid esters can be produced, but the yield is unsatisfactory and operational costs are high
Solution Approach 1:
The patent combines multiple reaction steps into a one-pot process where the starting material undergoes sequential transformations (extraction, esterification, and cyclization) in a single reaction vessel without intermediate isolation. This merging of steps improves overall yield by minimizing material loss and reduces operational costs by eliminating multiple processing cycles
Solution Approach 2:
The patent implements a continuous one-pot process where reactions proceed sequentially without interruption or intermediate workup. The reaction mixture is continuously transformed from starting material through intermediates to final product, maintaining useful action throughout and improving productivity while reducing energy loss
3Ease of manufacture
If multiple solvents and intermediate isolation steps are used in the current process, then the reaction can proceed through different stages, but the process complexity and expenditure increase
Solution Approach 1:
The patent merges extraction, esterification, and cyclization steps into a single integrated reaction sequence. All transformations occur in one pot with the starting material dissolved in the solvent system, eliminating the need for separate equipment and intermediate isolation steps while maintaining reaction control
Solution Approach 2:
The solvent system (toluene, xylene, ethyl acetate, or their mixtures with water) serves multiple functions throughout the reaction sequence: it acts as extraction solvent, esterification medium, and cyclization solvent. This multi-functionality simplifies the overall process by eliminating the need for solvent changes or additional equipment
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 simplifies the production of cis-alkoxy-substituted spirocyclic phenylacetylamino acid esters, achieving better yields and higher purity while reducing environmental impact by using more eco-friendly solvents, primarily toluene or xylene.
Implementation Method 1
compounds of the formula (IIa) are converted in the presence of a base into compounds of the formula (IIb)
Implementation Method 2
This solution is esterified with methanol under sulphuric acid catalysis to give compounds of the formula (I)
Implementation Method 3
Since the compounds of the formula (I) do not remain dissolved in chlorobenzene at room temperature, the solvent chlorobenzene is replaced by dimethylacetamide
Data Source
AI summary
The present invention relates to a novel process for preparing cis-alkoxy-substituted spirocyclic phenylacetylamino acid esters and cis-alkoxy-substituted spirocyclic 1H-pyrrolidine-2,4-dione derivatives, and also to novel intermediates and starting materials which are produced and/or used in the process according to the invention.