Bromination of 2-Amino-5-Bromobenzamide Derivatives

Solution Overview

Problem

Current methods for preparing 3-substituted 2-amino-5-bromobenzoic acid derivatives are inefficient due to inhibition by high concentrations of hydrobromic acid, which reduces yields and requires optimization for effective bromination.

Innovation Solution

A method involving the introduction of bromine gas into a liquid containing a compound of Formula 4, in the presence of a base such as sodium hydroxide or sodium acetate, using organic solvents like acetic acid, and controlling reaction conditions like temperature and solvent volume to minimize hydrobromic acid inhibition and enhance yield.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional bromination methods are used to prepare 3-substituted 2-amino-5-bromobenzoic acid derivatives, then bromination can proceed, but high concentrations of hydrobromic acid inhibit the reaction, reducing yields and requiring optimization

Engineering Contradiction:

Improvebromination efficiencyVSAvoidhydrobromic acid inhibition

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful hydrobromic acid byproduct into a beneficial component by using it in situ to generate bromine from sodium bromate and sodium bromide. This eliminates the need to remove or neutralize the acid while simultaneously providing the brominating agent, thus converting a harmful factor into a useful one that drives the reaction forward

Inventive Principle:

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

Solution Approach 2:

The patent introduces sodium bromate and sodium bromide as intermediary substances that react with hydrobromic acid to generate molecular bromine in situ. These intermediaries mediate between the hydrobromic acid byproduct and the bromination reaction, allowing the acid to serve as a precursor for the brominating agent rather than merely as an inhibitor

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If conventional methods are used, then bromination can occur, but yields are reduced due to hydrobromic acid inhibition, requiring process optimization

Engineering Contradiction:

Improveproduct yieldVSAvoidhydrobromic acid inhibition

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful hydrobromic acid byproduct into a beneficial component by using it in situ to generate bromine from sodium bromate and sodium bromide. This eliminates the need to remove or neutralize the acid while simultaneously providing the brominating agent, thus converting a harmful factor into a useful one that drives the reaction forward

Inventive Principle:

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

Solution Approach 2:

The patent introduces sodium bromate and sodium bromide as intermediary substances that react with hydrobromic acid to generate molecular bromine in situ. These intermediaries mediate between the hydrobromic acid byproduct and the bromination reaction, allowing the acid to serve as a precursor for the brominating agent rather than merely as an inhibitor

Inventive Principle:

Principle #24Intermediary (Mediator)

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 effectively prepares 3-substituted 2-amino-5-bromobenzoic acid derivatives with high yields and purity by controlling reaction conditions, reducing the inhibitory effects of hydrobromic acid and optimizing bromination efficiency.

Implementation Method 1

in the presence of a base such as sodium hydroxide or sodium acetate

Methodology Applied

Scientific EffectNeutralization reaction: Chemical Bonding

Implementation Method 2

introduction of reagent (a) (i.e. a gas containing bromine) into reagent (b) (i.e. a liquid containing a compound of Formula 4)

Methodology Applied

Scientific EffectElectrophilic aromatic substitution: Chemical Bonding

Data Source

PatentEP2213654B1Process for preparing 2-amino-5-bromobenzamide derivatives

Publication Date: 2014.01.22 EI DU PONT DE NEMOURS & CO

AI summary

Disclosed is a method for preparing a compound of Formula 2 comprising introducing (a) a gas containing bromine into (b) a liquid containing a compound of Formula 4 wherein Y is Br; R1 is NHR3; R2 is CH3 or Cl; and R3 is H, C1-C4 alkyl, cyclopropyl, cyclopropylcyclopropyl, cyclopropylmethyl or methylcyclopropyl.