NDAC Synthesis via Di-tert-butyl-L-cystine Extraction
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Solution Overview
Problem
Current methods for synthesizing N,N'-diacetyl-L-Cystine (NDAC) are inefficient due to the use of thiol-containing raw materials, which result in unpleasant odors and stability issues, and require complex purification processes, making large-scale commercial production impractical.
Innovation Solution
A two-step process using di-tert-butyl-L-cystine as a starting material, where acetic anhydride is used for acetylation followed by formic acid to remove tert-butyl groups, allowing for high-yield production without the need for extractive workup or purification, using water and formic acid as green solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If thiol-containing raw materials (e.g., N-acetyl cysteine) are used for synthesizing NDAC, then the synthesis can proceed, but unpleasant sulfurous odors are generated and stability issues occur
Solution Approach 1:
The patent removes the problematic thiol-containing intermediate (N-acetyl cysteine) from the synthesis pathway entirely. Instead, it uses cystine as the starting material which directly undergoes acetylation to produce NDAC, eliminating the source of sulfurous odors while maintaining synthesis efficiency
Solution Approach 2:
The patent introduces a different intermediate pathway using cystine as the mediator substance. Cystine serves as the starting material that is acetylated to form NDAC, replacing the thiol-containing N-acetyl cysteine intermediate and thus avoiding odor generation while preserving the synthetic route
2Ease of manufacture
If thiol-containing derivatives (e.g., N-acetyl cysteine) are used, then synthesis can be achieved, but stability and odor problems occur
Solution Approach 1:
The patent extracts and removes the unstable thiol-containing N-acetyl cysteine from the synthesis pathway. By using cystine as the starting material that directly acetylates to NDAC, the patent eliminates the stability and odor problems associated with thiol intermediates while maintaining ease of manufacture
Solution Approach 2:
The patent changes the chemical parameters of the starting material from thiol-containing N-acetyl cysteine to cystine (an amide). This parameter change in the molecular structure eliminates the instability and odor issues while preserving the feasibility of the synthesis process
3Manufacturing precision
If complex purification processes are used to achieve high purity NDAC, then product quality improves, but manufacturing complexity and cost increase
Solution Approach 1:
The patent performs preliminary action by selecting cystine as the starting material, which inherently avoids the formation of problematic thiol-containing impurities. This preliminary choice eliminates the need for complex extractive workup and purification processes, achieving high purity NDAC through a simpler route
Solution Approach 2:
The patent converts the potential harm of requiring complex purification into a benefit by choosing a starting material (cystine) that naturally produces cleaner reaction products. The absence of thiol-containing impurities transforms what would have been a purification challenge into a straightforward isolation process
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 achieves high yields (>88% and >97%) with improved purity and stability, avoiding sulfurous odors and toxic solvents, making NDAC more suitable for cosmetic applications.
Implementation Method 1
Acetylating to obtain N,N'-diacetyl-di-tert-butyl-L-cystine (2)
Implementation Method 2
Removing the tert-butyl groups using formic acid as both a reagent and a solvent
Data Source
AI summary
An effective process of making Ν,Ν'-diacetyl-L-Cystine ("NDAC"), which process is fast, green, does not require labor-intensive isolation or purification of the product, by yielding products in desired ratio, and has improved yield and purity. The process comprising the steps of Forming a reaction mixture, starting with a cystine derivative di-tert- butyl-L-cystine as the dihydrochloride form; Acetylating said di-tert-butyl-L-cystine to obtain Ν,Ν'-diacetyl-di-tert- butyl-L-cystine; followed by Removing said tert- butyl groups from said Ν,Ν'-diacetyl-di-tert-butyl- L-cystine to obtain Ν,Ν'-diacetyl-L-cystine product; and Isolating said Ν,Ν'-diacetyl-L-Cystine product from said reaction mixture; wherein said acetylating agent is acetic anhydride.