Nitroguanidine Synthesis via Saturated Salt Stabilization
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Solution Overview
Problem
Existing methods for producing nitroguanidine derivatives with insecticidal activity are costly due to the need for expensive isourea compounds and suffer from low stability and excessive by-product generation, limiting industrial applicability.
Innovation Solution
A process involving the reaction of nitroisourea derivatives with amines in an aqueous solution with dissolved sodium chloride at greater than 50% saturation, in the presence of a base, to suppress decomposition and by-product formation, thereby enhancing selectivity and yield while using inexpensive intermediates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If expensive isourea compounds are used as intermediates, then guanidine derivatives with insecticidal activity can be produced, but production cost increases
Solution Approach 1:
The patent replaces expensive isourea compounds with inexpensive nitroisourea derivatives as intermediates. The nitroisourea compounds are cheaper, less stable intermediates that decompose readily, but by conducting the reaction in saturated sodium chloride solution, the patent achieves stable production of the desired guanidine derivatives with insecticidal activity at lower cost
Solution Approach 2:
The patent changes the reaction medium parameter by using saturated sodium chloride solution instead of conventional solvents. This parameter change stabilizes the reaction of nitroisourea derivatives, enabling the use of these inexpensive intermediates to produce high-quality insecticidal guanidine derivatives
2Ease of manufacture
If nitroisourea derivatives are used as intermediates, then production cost decreases, but stability and by-product generation become problematic
Solution Approach 1:
The patent changes the physical-chemical parameter of the reaction medium by using saturated sodium chloride solution. This high ionic strength environment stabilizes nitroisourea derivatives during the reaction, preventing their decomposition while maintaining the cost advantage of using these inexpensive intermediates
Solution Approach 2:
The saturated sodium chloride solution creates an inert reaction environment that protects the unstable nitroisourea intermediates from decomposition. The high salt concentration suppresses side reactions and stabilizes the intermediates throughout the reaction process
3Productivity
If conventional exchange reaction methods are used, then guanidine derivatives can be produced, but mercaptan by-products with strong odor are generated
Solution Approach 1:
The patent eliminates the problematic exchange reaction pathway that generates mercaptan by-products. By using nitroisourea derivatives as intermediates instead of isothiourea derivatives, the patent removes the source of mercaptan generation entirely from the synthesis route
Solution Approach 2:
The patent uses nitroisourea derivatives that decompose cleanly to give the desired guanidine products without forming persistent harmful by-products like mercaptans. The intermediates are consumed completely in the reaction, leaving no harmful residues
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 achieves high-yield production of nitroguanidine derivatives with excellent insecticidal activity, reducing production costs and by-product generation, making the process industrially advantageous and environmentally sustainable.
Implementation Method 1
an aqueous solution wherein sodium chloride is dissolved at not less than 50% of its saturated solubility
Data Source
AI summary
Disclosed is an improved process for producing nitroguanidine derivatives represented by the following general formula (3), which has an insecticidal activity, or a salt thereof. Specifically, disclosed is a process for producing nitroguanidine derivatives represented by the following general formula (3) or a salt thereof, in which nitroisourea derivatives represented by the following general formula (1) or a salt thereof and compounds represented by the following general formula (2) or a salt thereof are reacted in the presence of a base in an aqueous solution wherein an inorganic salt is dissolved at not less than 50% of its saturated solubility, wherein, in the formula, R1 represents an alkyl group having 1 to 4 carbon atoms or a benzyl group; R2 represents an alkyl group having 1 to 4 carbon atoms; and R3 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, wherein, in the formula, R4, R5 and R6 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; and Q represents a 5- or 6-membered heterocyclic group which contains at least one each of a nitrogen atom, an oxygen atom and a sulfur atom and may be substituted with a halogen atom, wherein, in the formula, R2 represents an alkyl group having 1 to 4 carbon atoms; R3, R4, R5 and R6 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; and Q represents a 5- or 6-membered heterocyclic group which contains at least one each of a nitrogen atom, an oxygen atom and a sulfur atom and may be substituted with a halogen atom.