Fmoc-Protected Amino Compound Quantification via Dibenzofulvene

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Solution Overview

Problem

Existing methods for quantitatively determining compounds with an Fmoc-protected amino group are inaccurate due to variations in molar absorption coefficients and the instability of dibenzofulvene, especially when authentic samples are unavailable for unnatural amino acids and peptides, leading to errors in quality control for medicament manufacturing.

Innovation Solution

A method involving the removal of the Fmoc protecting group to quantify dibenzofulvene or its derivative, setting identical measurement conditions, and stabilizing dibenzofulvene with acid to accurately determine the compound content to the first decimal place.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If chromatography is used to determine Fmoc group content, then quantitative determination is possible, but measurement precision deteriorates due to variations in molar absorption coefficients

Engineering Contradiction:
Improvecontent measurement accuracyVSAvoidreliability of quantitative determination
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent extracts the Fmoc group from the compound through deprotection reaction, converting it into dibenzofulvene which can then be quantified. This separation of the Fmoc group from the original compound allows for more reliable quantitative determination by eliminating the interference of varying molar absorption coefficients of different compounds.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces dibenzofulvene as an intermediary substance that mediates the quantification process. By converting the Fmoc group into dibenzofulvene through deprotection, the method uses this intermediary to bridge the gap between the original compound and the quantification measurement, ensuring consistent and reliable results.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If authentic samples are synthesized for each compound, then measurement precision improves, but device complexity and time consumption increase

Engineering Contradiction:
Improvecontent measurement accuracyVSAvoidcomplexity of sample preparation
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent enables the compound itself to serve as the source of the quantifiable substance through in-situ deprotection. The Fmoc group on the compound undergoes deprotection to generate dibenzofulvene directly in the measurement sample, eliminating the need for separate authentic sample synthesis and preparation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent performs the deprotection action preliminarily before measurement, converting the Fmoc group into dibenzofulvene in advance. This preliminary conversion ensures that the compound is already in the measurable form when analysis is performed, avoiding the need for complex authentic sample synthesis.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If dibenzofulvene is used for quantification, then quantitative determination is enabled, but reliability deteriorates due to instability and degradation of dibenzofulvene

Engineering Contradiction:
Improvequantification accuracyVSAvoidstability of dibenzofulvene
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent applies prior cushioning by immediately stabilizing dibenzofulvene with acid after deprotection, preventing its degradation before measurement. This preemptive stabilization ensures that dibenzofulvene remains stable throughout the measurement process, maintaining quantification accuracy.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent converts the harmful effect of dibenzofulvene degradation into a beneficial stabilization process by using acid treatment. The acid not only stabilizes dibenzofulvene but also confirms the deprotection reaction, turning the potential harm of instability into a reliable measurement foundation.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Ease of operation

If titration method is used, then ease of operation improves, but measurement precision deteriorates due to interference from acidic impurities

Engineering Contradiction:
Improveease of testingVSAvoidcontent measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent extracts the Fmoc group from the compound through deprotection reaction, converting it into dibenzofulvene which can then be quantified. This separation of the Fmoc group from the original compound allows for more reliable quantitative determination by eliminating the interference of varying molar absorption coefficients of different compounds.

Inventive Principle:
Principle #2Taking out (Extraction)

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

Enables precise and easy quantification of compounds with Fmoc-protected amino groups, suitable for quality control in medicament production, reducing errors and ensuring accurate content determination.

Implementation Method 1

a base is used to remove the protecting group from the compound, thereby quantitatively determining dibenzofulvene or a derivative thereof

Methodology Applied
Scientific EffectBase-catalyzed deprotection reaction: Chemical Bonding

Implementation Method 2

it has been confirmed that when a base is used to remove the protecting group from the compound, dibenzofulvene or a derivative thereof is produced in a reaction mixture, and that dibenzofulvene or a derivative thereof can be stabilized by using acid

Methodology Applied
Scientific EffectAcid stabilization: Chemical Bonding

Data Source

PatentEP4046982B1Method for quantifying amino group-containing compound protected by protecting group having fmoc skeleton
Publication Date: 2025.12.03 CHUGAI PHARMA CO LTD
  • EP4046982B1 patent drawingFigure 1
  • EP4046982B1 patent drawingFigure 2
  • EP4046982B1 patent drawingFigure 3

AI summary

The present inventors discovered that compounds containing an amino group protected with a protecting group having an Fmoc skeleton can be quantitatively determined accurately by removing the protecting group having the Fmoc skeleton from the compounds and measuring the contents of dibenzofulvene or its derivative thereby produced.