1-Hydroxyalkyl Triazole Carboxylic Acid Route Avoiding Cis-Trans Isolation
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Solution Overview
Problem
Existing methods for preparing Prothioconazole suffer from product isolation issues due to cis-trans isomerism associated with the hydrazinylidene C═N double bond, particularly in large-scale production.
Innovation Solution
A method involving a condensation reaction with glyoxylic acid or a glyoxylate salt, followed by an addition-cyclization reaction with thiocyanic acid or a thiocyanate salt, and then dehydrogenation with an oxidant to produce 1-hydroxyalkyl-5-mercapto-1,2,4-triazole-3-carboxylic acid, which can be further decarboxylated to yield 2-hydroxyalkyl-1,2,4-triazole-3-thione, suitable for large-scale industrial production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the hydrazinylidene C═N double bond intermediate is used in large-scale production, then the synthesis route is established, but product isolation problems occur due to cis-trans isomerism
Solution Approach 1:
The patent extracts and eliminates the problematic hydrazinylidene C═N double bond intermediate from the synthesis route. By redesigning the synthetic pathway to avoid this intermediate, the invention removes the source of cis-trans isomerism that causes isolation difficulties, thereby enabling straightforward product isolation in large-scale production while maintaining productivity
Solution Approach 2:
The patent segments the synthesis route into distinct stages, placing the introduction of the C═N double bond at a later stage after the core structure is formed. This segmentation allows the main synthesis pathway to proceed without isomerism complications, and the C═N bond is introduced only when necessary, avoiding the isolation problems during bulk production
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
The method provides structurally-novel, multi-functional compounds with high yield, low waste generation, and excellent safety, enabling the synthesis of valuable compounds like Prothioconazole, addressing the deficiencies in existing preparation methods.
Implementation Method 1
subjecting a hydroxyalkylhydrazine compound (2) to a condensation reaction with glyoxylic acid or a glyoxylate salt to produce a condensation product
Implementation Method 2
subjecting the condensation product to an addition-cyclization reaction with thiocyanic acid or a thiocyanate salt in the presence of an acid A to produce an addition-cyclization product
Implementation Method 3
subjecting the addition-cyclization product to dehydrogenation under the action of an oxidant to yield the 1-hydroxyalkyl-5-mercapto-1,2,4-triazole-3-carboxylic acid compound of formula (1)
Data Source
AI summary
A 1-hydroxyalkyl-5-mercapto-1,2,4-triazole-3-carboxylic acid compound of formula (1):in which R1, R2, R3 and R4 are each independently selected from the group consisting of hydrogen, unsubstituted and substituted C1-C18 alkyl, unsubstituted and substituted C1-C18 alkenyl, unsubstituted and substituted C3-C18 cycloalkyl, unsubstituted and substituted C6-C14 aryl, unsubstituted and substituted C1-C13 heteroaryl, unsubstituted and substituted C7-C18 aralkyl, unsubstituted and substituted C8-C18 arylalkenyl, and unsubstituted and substituted C7-C18 aryloxyalkyl, and n is 1, 2, 3 or 4. A preparation method for the 1-hydroxyalkyl-5-mercapto-1,2,4-triazole-3-carboxylic acid compound is also provided, in which a hydroxyalkylhydrazine compound is used as a starting material, and undergoes a condensation reaction, an addition-cyclization reaction and dehydrogenation in sequence to obtain the 1-hydroxyalkyl-5-mercapto-1,2,4-triazole-3-carboxylic acid compound. An application of such compound in the preparation of a 2-hydroxyalkyl-1,2,4-triazole-3-thione compound is also provided.