- Environment-friendly 2-ethyl-4-methylimidazole synthesis method
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The invention discloses an environment-friendly synthesis method of 2-ethyl-4-methylimidazole, and belongs to the technical field of organic synthesis. The method comprises: generating aminopropyl propionamide at a temperature of 80 DEG C from low-toxicity methyl propionate and 1,2-diaminopropane according to a proper reaction ratio; carrying out cyclization with water on the aminopropyl propionamide and an aromatic hydrocarbon in the presence of a catalyst to generate 2-ethyl-4-methylimidazoline; and dehydrogenating the 2-ethyl-4-methylimidazoline at a temperature of 120-40 DEG C in the presence of a pd/c catalyst to prepare the 2-ethyl-4-methylimidazole. According to the invention, the 2-ethyl-4-methylimidazole is prepared by using the method, so that the use of high-toxicity propionitrile, high-pollution aldehyde and ammonia and high-risk Raney nickel catalysts capable of burning in the presence of air are avoided, no waste ammonia is generated in the production process, and the method belongs to an environment-friendly method for preparing the 2-ethyl-4-methylimidazole.
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Paragraph 0006; 0007; 0008
(2020/03/09)
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- Electrophilically activated nitroalkanes in reaction with aliphatic diamines en route to imidazolines
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A novel synthetic methodology for the assembly of imidazolines via an unusual reaction between nitroalkanes and aliphatic 1,2-diamines in the presence of phosphorous acid is described. In contrast to the related highly efficient preparation of benzimidazoles from aromatic amines, this process represents a major synthetic challenge and for a long time was elusive. Analysis of the method limitations is provided.
- Aksenov, Alexander V.,Aksenov, Nicolai A.,Arutiunov, Nikolai A.,Malyuga, Vladimir V.,Ovcharov, Sergey N.,Rubin, Michael
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p. 39458 - 39465
(2019/12/14)
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- Preparation method of 2-ethyl-4-methylimidazole
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The invention discloses a preparation method of 2-ethyl-4-methylimidazole. The preparation method comprises steps as follows: diamine and propionitrile have a cyclization reaction sequentially at the temperature of 80-110 DEG C and 120-140 DEG C under the catalysis of a catalyst; a product after the cyclization reaction has a dehydrogenation reaction through raney nickel at the temperature of 170-200 DEG C, and 2-ethyl-4-methylimidazole is obtained. The preparation method has the advantages that 2-ethyl-4-methylimidazole is prepared with a substep method, the process cost is reduced, the reaction process is optimized, the operation is simple and convenient, the pollution is reduced, and the reaction yield is high.
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Paragraph 0019; 0030
(2016/10/10)
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- Synthesis of 2,4(5)-Bis(hydroxymethyl)imidazoles and 2,4(5)-Bisimidazoles: Precursors of 2,4(5)-Connected Imidazole Crown Ethers
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Two syntheses of 1--2,4-bisimidazole, 3, a precursor to imidazole-containing crown ethers, are described.The first involved hydroxymethylation of 1-benzylimidazole with formaldehyde to afford 1-benzyl-2,5-bis(hydroxymethyl)imidazole (5) (20percent yield), which was elaborated into 3 in four steps.An alternative and more efficient route involved coupling of diamine 17b with the imino ether obtained from nitrile 11b to afford imidazoline 18b.The imidazoline was found to oxidize under Swern conditions, providing a mild new method of imidazole synthesis.Sulfamylation and debenzylation produced 3.This approach was also applied to the synthesis of 1--2,4-bis(hydroxymethyl)imidazole (2).Diol 3 was converted into 2,4-connected imidazole crown ethers, one of which (4) formed a crystalline complex with water.The complex structure was determined by X-ray crystallography.
- Zimmerman, Steven C.,Cramer, Katherine D.,Galan, Adam A.
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p. 1256 - 1264
(2007/10/02)
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