Phenacyl-Protected Sialic Acid in Boc Solid Phase Synthesis
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Solution Overview
Problem
The existing solid phase synthesis methods, particularly those using the Boc group, face challenges in retaining sialic acid at the sugar chain non-reducing terminal due to strong acid conditions, leading to degradation and low yields of glycopeptides with sialyl sugar chains.
Innovation Solution
The use of a phenacyl group as a protecting agent for the carboxyl group of sialic acid in the Boc solid phase synthesis method, combined with specific acid conditions like trifluoroacetic acid/trifluoromethanesulfonic acid/dimethyl sulfide/m-cresol, allows for the retention of sialic acid and improved yield of glycopeptides with sialyl sugar chains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Boc solid phase synthesis method is used, then peptide chain elongation can proceed efficiently, but sialic acid at the sugar chain non-reducing terminal is degraded due to strong acid conditions
Solution Approach 1:
The phenacyl group is introduced as a protecting group for the carboxyl group of sialic acid before the Boc solid phase synthesis process. This preliminary protection prevents the degradation of sialic acid during the subsequent strong acid treatment, allowing the peptide chain elongation to proceed efficiently while maintaining sialic acid integrity.
Solution Approach 2:
The phenacyl group acts as an intermediary protecting group that mediates between the strong acid conditions required for Boc deprotection and the sensitivity of sialic acid. This intermediary structure allows the strong acid to access the peptide backbone without directly attacking the sialic acid, thus enabling both efficient synthesis and high retention.
2Ease of manufacture
If conventional protecting groups are used for sialic acid, then synthesis can proceed, but yield remains low due to insufficient retention of sialic acid
Solution Approach 1:
The invention changes the protecting group parameter from conventional groups (such as methyl or benzyl) to the phenacyl group. This parameter change provides optimal protection against acid-mediated degradation while maintaining compatibility with the Boc solid phase synthesis conditions, thereby significantly improving the yield of glycopeptides with sialyl sugar chains.
3Ease of operation
If strong acid is used for deprotection and cleavage, then peptide can be released from resin, but sialic acid structure is compromised
Solution Approach 1:
The phenacyl protecting group is installed on the sialic acid carboxyl group before the deprotection and cleavage steps. This preliminary protection ensures that when strong acid is applied for Boc group removal and peptide release, the sialic acid structure remains intact while the peptide is successfully liberated from the resin.
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 approach enables the high-yield synthesis of glycopeptides with sialyl sugar chains, maintaining the integrity of sialic acid and allowing for the production of glycopeptides with uniform sugar chain structures suitable for pharmaceutical applications.
Implementation Method 1
the carboxyl group of said sialic acid is protected with a phenacyl group
Implementation Method 2
specific acid conditions like trifluoroacetic acid/trifluoromethanesulfonic acid/dimethyl sulfide/m-cresol
Data Source
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AI summary
[Technical Promblem] To provide a method for manufacturing that enables to obtain a targeted glycopeptide harboring a sialyl sugar chain in high yield without decomposing sialic acid at a non-reducing terminal of sugar chain when the glycopeptide is synthesized by a Boc solid phase synthesis method. [Solution to Problem] The present invention is characterized in that the Boc-sialylglycosylated amino acid derivative used in Boc solid phase synthesis method is one where the carboxyl group of the sialic acid at the sugar chain non-reducing terminal is protected with a phenacyl group.