Hydrazine Synthesis via Urea Intermediate and Shestakov Rearrangement
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Solution Overview
Problem
The existing synthesis pathway for compounds used in treating papilloma virus involves nitroso compounds, which are hazardous and not suitable for industrial use, and strict standards for residual concentrations necessitate an alternative method.
Innovation Solution
A method using a urea intermediate to produce hydrazine through the Shestakov rearrangement, with NaOCl as a rearrangement inducing agent, replacing the hazardous nitroso compound pathway, and involving steps like reaction with trichloroacetyl isocyanate and basic medium treatment to obtain the desired hydrazine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If nitroso compounds are used as intermediates in the synthesis pathway, then the hydrazine can be produced through the conventional route, but the process becomes hazardous and unsuitable for industrial use due to the dangerous nature of nitroso compounds
Solution Approach 1:
The patent introduces a urea intermediate as a safe mediator to replace the hazardous nitroso compound in the synthesis pathway. The amine first reacts with phosgene to form a carbamoyl chloride intermediate, which then reacts with another amine molecule to form the urea intermediate. This urea intermediate subsequently undergoes the Shestakov rearrangement to produce the desired hydrazine product. This intermediary pathway eliminates the need for dangerous nitroso compounds while maintaining synthetic efficiency and industrial suitability.
2Reliability
If nitroso compounds are used in the synthesis pathway, then the conventional synthesis route can be followed, but strict regulatory standards for residual concentrations make the process unacceptable for pharmaceutical production
Solution Approach 1:
The urea intermediate serves as a safe intermediary that eliminates residual nitroso compound concerns. The reaction pathway through urea formation and subsequent Shestakov rearrangement produces hydrazine without generating nitroso compound residues, ensuring compliance with pharmaceutical regulatory standards for residual concentrations.
Solution Approach 2:
The invention extracts and eliminates the hazardous nitroso compound step from the synthesis pathway entirely. By removing the nitrosation step and replacing it with the urea-based Shestakov rearrangement pathway, the process eliminates the source of residual nitroso compounds that would otherwise require strict control to meet pharmaceutical standards.
3Productivity
If the conventional nitroso pathway is used, then the synthesis can proceed through established steps, but the process yields are lower compared to the new urea-based method
Solution Approach 1:
The patent changes the chemical parameters and reaction conditions by employing the Shestakov rearrangement mechanism instead of conventional nitroso reduction. This parameter change involves using specific base catalysts (such as alkali metal hydroxides or organic bases) and controlling pH conditions to facilitate the rearrangement of the urea intermediate to hydrazine, resulting in improved yields compared to the nitroso pathway.
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 provides a safer, industrially viable route to produce hydrazine with improved yields, suitable for pharmaceutical use, addressing the hazards and regulatory concerns of the previous method.
Implementation Method 1
The present invention also relates to a method for producing a compound of formula (V)... by Shestakov rearrangement. This reaction is described in the literature for variously substituted ureas
Implementation Method 2
Production of hydrazine from the corresponding amine is carried out by nitrosation of the amine in the presence of NaNO2 to give the corresponding N-nitroso compound
Data Source
AI summary
The invention relates to a method for producing a hydrazine of general formula (I) and the pharmaceutically acceptable salts thereof from an amine of formula (II), characterised in that said method uses a urea of formula (III) as a synthesis intermediate.