On-Resin Cyclization of Peptidic Compounds via Fmoc Chemistry
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for synthesizing cyclic peptides are limited by compatibility issues with acid-sensitive residues and the need for multiple processing steps, particularly in achieving high-throughput synthesis with improved cell membrane permeability and chemical diversity.
Innovation Solution
A method involving a thiophilic catalyst, non-nucleophilic base, and specific reaction conditions for on-resin cyclization, allowing for the efficient incorporation of peptoids and N-methyl substituted amino acids, using a sulfonamide resin compatible with Fmoc chemistry to achieve high-yield cyclized peptidic compounds with head-to-tail and sidechain-to-tail linkages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If BOC chemistry with tert-butyloxycarbonyl protecting groups is used for linear peptide assembly, then on-resin cyclization can be achieved, but acid-sensitive residues such as N-methyl amino acids and peptoids cannot be incorporated due to acid deprotection steps
Solution Approach 1:
The patent changes the chemical parameters of the protecting group system from BOC (acid-labile) to Fmoc (base-labile), enabling compatibility with acid-sensitive residues while maintaining on-resin cyclization capability through base-triggered cyclization conditions
Solution Approach 2:
The patent introduces an N-acylsulfonamide intermediate as a mediator that enables cyclization under base conditions rather than acid conditions, serving as a bridge between Fmoc deprotection and cyclization formation
2Manufacturing precision
If solid-phase peptide synthesis with cleavage and solution phase cyclization is used, then cyclic peptides can be synthesized, but the process requires too many processing and handling steps for large scale compound screening
Solution Approach 1:
The patent merges the cyclization step with the solid-phase synthesis process by enabling on-resin cyclization, combining what were previously separate operations (solution-phase cyclization after cleavage) into a single integrated process step
Solution Approach 2:
The patent performs preliminary preparation of the N-acylsulfonamide intermediate during solid-phase synthesis, positioning the peptide in a state ready for cyclization while still attached to the resin, before triggering cyclization in the final step
3Productivity
If existing on-resin cyclization methods are used, then processing steps are reduced, but they require BOC chemistry which is incompatible with N-methyl amino acids and peptoids needed for improved cell membrane permeability
Solution Approach 1:
The patent changes the triggering condition parameter from acid (BOC) to base (Fmoc), enabling the use of peptoids and N-methyl amino acids while maintaining high synthesis efficiency through automated solid-phase synthesis and on-resin cyclization
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 reliable preparation of cyclized peptidic compounds with improved chemical diversity and cell membrane permeability, overcoming the limitations of existing synthetic methods by simplifying the process and increasing efficiency.
Implementation Method 1
forming a cyclization reaction mixture comprising a thiophilic catalyst, a non-nucleophilic base, and a compound of Formula II
Implementation Method 2
forming a cyclization reaction mixture comprising a thiophilic catalyst, a non-nucleophilic base, and a compound of Formula II
Data Source
AI summary
The present disclosure provides efficient and reliable methods for preparing cyclized peptidic compounds. Advantageously, the currently described methods allow for on-resin cyclization using a limited number of processing steps, while increasing the chemical diversity available for the cyclized peptidic compounds produced.