Paliperidone Synthesis via Palmitate Ester Intermediate
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Solution Overview
Problem
Current processes for preparing Paliperidone and Paliperidone Palmitate face challenges in achieving high purity and yield, with existing methods often resulting in impurities and inefficiencies.
Innovation Solution
A novel intermediate, 3-(2-chloroethyl)-6,7,8,9-tetrahydro-9-hydroxy-2-methyl-4H-pyrido[1,2-a]pyrimidine-4-one Palmitate ester, is used in a process involving combinations with fatty acids, organic or inorganic bases, and solvents to synthesize Paliperidone and Paliperidone Palmitate, optimizing reaction conditions to achieve high purity and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing processes are used for preparing Paliperidone and Paliperidone Palmitate, then the synthesis can be performed with conventional methods, but the purity and yield are insufficient and impurities are generated
Solution Approach 1:
The synthesis process is divided into distinct stages: first forming the palmitate ester intermediate (3-(2-chloroethyl)-6,7,8,9-tetrahydro-2-methyl-9-hydroxy-4H-pyrido[1,2-a]pyrimidine-4-one palmitate ester), then reacting this intermediate with 6-fluoro-3-(4-piperidinyl)-1,2-benzisoxazole. This segmentation allows each stage to be optimized independently, achieving high purity (>99%) while managing synthesis complexity through systematic process design
Solution Approach 2:
The patent introduces a novel palmitate ester intermediate as a key mediator in the synthesis pathway. This intermediate compound serves as a bridge between the starting materials and the final products, enabling high-yield transformations with minimal impurity formation. The intermediate's stable structure facilitates controlled reactions and simplifies purification steps
2Productivity
If existing processes are used for preparing Paliperidone and Paliperidone Palmitate, then conventional synthesis methods can be applied, but the yield is insufficient
Solution Approach 1:
The patent optimizes reaction parameters including temperature, solvent selection, and base catalyst choice to achieve high yields. The first stage uses specific conditions to form the palmitate ester intermediate with high conversion, while the second stage employs optimized parameters for the coupling reaction with benzisoxazole, achieving overall high productivity without excessive reaction times
Solution Approach 2:
The palmitate ester intermediate is prepared in advance through a dedicated first stage reaction, ensuring high purity and yield before proceeding to the final coupling reaction. This preliminary formation of the intermediate with optimized conditions lays the foundation for high overall yield in the subsequent reaction step
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 Paliperidone and Paliperidone Palmitate with purities exceeding 99% and high yields, significantly reducing impurities such as diketone impurities to less than 0.1%, thereby improving the efficiency and quality of the synthesis.
Implementation Method 1
combining 3-(2-chloroethyl)-6,7,8,9-tetrahydro-2-methyl-9-hydroxy-4H-pyrido[1,2-a]pyrimidine-4-one with fatty acid in presence of at least one organic or inorganic base
Implementation Method 2
adding acid halide to mixture and maintaining the mixture for time sufficient to give a novel intermediate of compound 3-(2-chloroethyl)-6,7,8,9-tetrahydro-2-methyl-9-hydroxy-4H-pyrido[1,2-a]pyrimidine-4-one Palmitate ester
Implementation Method 3
3-(2-chloroethyl)-6,7,8,9-tetrahydro-2-methyl-9-hydroxy-4H-pyrido[1,2-a]pyrimidine-4-one Palmitate ester combines with 6-fluoro-3-(4-piperidinyl)-1,2-benzisoxazole or its mono-hydrochloride in organic solvent in presence of base
Data Source
AI summary
An improved process for the synthesis of 3-[2-[4-((6-fluoro-1,2-benzisoxazol-3-yl)-1-piperidinyl]-6,7,8,9-tetrahydro-9-hydroxy-2-methyl-4H-pyrido[1,2-a]-pyrimidin-4-one (Paliperidone) and Paliperidone Palmitate through a novel intermediate (2-Chloroethyl)-6,7,8,9-tetrahydro-2-methyl-9-hydroxy-4H-pyrido [1,2-a]pyrimidine-4-one Palmitate ester.