Spirodione Synthesis via Wittig Cyclization and Decarboxylation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for synthesizing spiro[2.5]octane-5,7-dione and spiro[3.5]nonane-6,8-dione face challenges such as the need for chromatography purification and the use of uncommon organic solvents and reagents, making them impractical for scale-up.
Innovation Solution
A multi-step process involving the reaction of (1-alkoxycyclopropoxy)trimethylsilane with a Wittig reagent to form cyclopropylidene carboxylic acid ester, followed by cyclization with dialkyl 1,3-acetonedicarboxylate, saponification, and decarboxylation to produce the desired compounds without chromatography, using high boiling point solvents for practicality in plant-scale synthesis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If flash chromatography is used for purification of intermediate and final product, then purity is improved, but manufacturing complexity and cost increase making it not practical for scale-up
Solution Approach 1:
The patent extracts and eliminates the chromatography purification step from the synthesis route by designing a reaction pathway that produces intermediates and final products with sufficient purity through selective chemical transformations and simple filtration, making the process scalable without complex purification equipment
Solution Approach 2:
The patent changes the reaction parameters and conditions to favor selective formation of desired products with high purity, allowing direct filtration or simple extraction instead of chromatography, thereby simplifying the manufacturing process for scale-up
2Productivity
If o-dichlorobenzene and sodium hydride are used as reagents, then reaction efficiency is improved, but safety and practicality worsen for pilot or manufacture scale
Solution Approach 1:
The patent replaces expensive and hazardous reagents like o-dichlorobenzene and sodium hydride with more benign, commercially available, and safer alternatives that achieve comparable reaction efficiency, making the process more practical for pilot and manufacturing scales
Solution Approach 2:
The patent modifies reaction conditions including temperature, solvent system, and reagent selection to maintain high reaction efficiency while using safer, more practical materials suitable for scaled production
3Productivity
If Wittig reagent and cyclobutanone are used at 100°C in silicon oil, then reactivity is improved, but process complexity and solvent removal steps increase
Solution Approach 1:
The patent eliminates the need for silicon oil as a high-boiling solvent by selecting alternative solvents with lower boiling points or by designing reactions that can proceed under solvent-free or aqueous conditions, thereby simplifying the workup and eliminating complex distillation steps
Solution Approach 2:
The patent optimizes reaction temperature and solvent selection to achieve the required reactivity without needing to heat to 100°C in silicon oil, using milder conditions that simplify product isolation and reduce process complexity
4Productivity
If enone has to be distilled out from silicon oil, then reaction progression is enabled, but time and energy consumption increase
Solution Approach 1:
The patent removes the energy-intensive distillation step from silicon oil by using alternative reaction media that allow for simpler product isolation through filtration, extraction, or crystallization, significantly reducing time and energy consumption
Solution Approach 2:
The patent utilizes phase transition properties of reaction components (such as crystallization from solution or immiscible liquid phases) to enable easy separation of products from reaction mixtures without requiring high-temperature distillation, thereby saving time and energy
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 high yield and purity (>98%) without chromatography, making it suitable for scale-up and reducing the use of uncommon solvents and reagents.
Implementation Method 1
reaction of (1-alkoxycyclopropoxy)trimethylsilane with a Wittig reagent to form cyclopropylidene carboxylic acid ester
Implementation Method 2
cyclization with dialkyl 1,3-acetonedicarboxylate
Implementation Method 3
saponification
Implementation Method 4
decarboxylation to produce the desired compounds
Data Source
AI summary
This invention relates to methods for the synthesis of spiro[2.5]octane-5, 7-dione and spiro[3.5]nonane-6, 8-dione which are useful as intermediates in the manufacture of pharmaceutically active ingredients.