Base-Catalyzed Formation of Imidazole Derivatives

Abstract

first_page settings Order Article Reprints Font Type: Arial Georgia Verdana Font Size: Aa Aa Aa Line Spacing:    Column Width:    Background: Open AccessAbstract Base-Catalyzed Formation of Imidazole Derivatives by A. N. Vasiliev 1,*, A. F. López 1 and A. J. Mocchi 2 1 CITeQ, Facultad Córdoba, Universidad Tecnológica Nacional, Córdoba, Argentina 2 Tecnomyl SRL, Parque Industrial Avay, Villeta, Paraguay * Author to whom correspondence should be addressed. Molecules 2000, 5(3), 338-339; https://doi.org/10.3390/50300338 Published: 22 March 2000 Download Download PDF Download PDF with Cover Download XML Download Epub Versions Notes IntroductionMany 2-(2´-imidazolin-2´-yl)-3-carboxypyridines possess bioactive properties that caused their use in agriculture as herbicides and defoliants [1]. Their activity is based on inhibition of acetohydroxy acid synthesis, reducing level of valine, leucine and isoleucine to disruption of protein and DNA synthesis. Known methods of their synthesis are based on multistep processes and result in low yield of aiming products. The first of them developed by Los with co-workers starts from substitutes diethyl pyridinedicarboxylates which were hydrolized to correspondent diacids, then dehydrated to anhydrides, treated by and 2-amino-2,3-dimethylbutiramide, and finally cyclized to desired products [2]. Another method includes oxidative condensation of 2-methylnicotinic acid with and 2-amino-2,3-dimethylbutiramide in the presence of elementary sulfur [3]. Due to their disadvantages, a development of simple and effective method of these compounds preparation is actual. In the present work a reaction of one-step formation of imidazoline ring is studied. Results and DiscussionThe reaction proceeds readily at heating and the final product precipitates as sodium salt. It takes place in accordance with suggested mechanism (Scheme). Firstly, N-substituted imide of dicarboxylic acid is forming. This intermediate undergoes an intramolecular condensation of one of carbonyl groups at the pyridine ring with amide group of N-substituent. Finally, the hydrolysis of amide bond occurs. Surprisengly this reaction occurs selectively to 2-position of pyridinic ring while 3-(2´-imidazolin-2´-yl)-pyridine was not detected. This method was applied to ethyl pyridine-2,3-dicarboxylates with (or without) alkyl substituents in pyridinic ring. ExperimentalSynthesis of 5-ethyl-2-(2´-imidazolin-2´-yl)-pyridine-3-carboxylic acidTo solution of diethyl ester of 5-ethylpyridine-2,3-dicarboxylic acid (2,51 g, 0,01 mol) and 2-amino-2,3-dimethylbutiramide (1,30 g, 0,01 mol) in 50 mL of dry toluene sodium metoxide (1,08 g, 0,02 mol) was added during 1 h at intensive stirring. The reactional mixture was refluxed for 1 h, cooled and white precipitate was filtered, washed by toluene, and dried on air. The yield of sodium salt of 5-ethyl-2-(2´-imidazolin-2´-yl)-pyridine-3-carboxylic acid was 2,39 g. The product was quantitatively converted into acidic form by dissolving in water and acidification to pH=3. Aiming compound was filtered, washed by water and dried at ambient temperature overnight. Yield 2.21 g (76.5%), m.p. 172-173ºC. Spectral dataIR (Jasco FT/IR-5300, pellets with KBr) cm-1: 1047, 1398, 1464, 1649, 1689, 1746; UV (Jasco UV/VIS-7800, acetonitrile) nm: 253. AcknowledgmentsThe authors wish to thank Geol. J. Fernández for his assistance in spectral analysis and Prof. E. R. Herrero for helpful discussion.References and NotesLadner, D.W. Recent Studies of Imidazolinone Herbicides and relative Compounds. In Chemistry of Plant Protection, v.10; Stelle, J., Ed.; Springer-Verlag: Berlin-Heidelberg, 1994; pp. 83–118. [Google Scholar] Los, M. 2-(2-imidazolin-2-yl)-pyridines and quinolines and use of said compounds as herbicide agents. Pat. USA 4798619; publ. 17.01.89, Wepplo, P.J. Process for the preparation of pyridyl and quinolyl imidazolinones. Pat. USA 4474962; publ. 02.10.84, Share and Cite MDPI and ACS Style Vasiliev, A.N.; López, A.F.; Mocchi, A.J. Base-Catalyzed Formation of Imidazole Derivatives. Molecules 2000, 5, 338-339. https://doi.org/10.3390/50300338 AMA Style Vasiliev AN, López AF, Mocchi AJ. Base-Catalyzed Formation of Imidazole Derivatives. Molecules. 2000; 5(3):338-339. https://doi.org/10.3390/50300338 Chicago/Turabian Style Vasiliev, A. N., A. F. López, and A. J. Mocchi. 2000. "Base-Catalyzed Formation of Imidazole Derivatives" Molecules 5, no. 3: 338-339. https://doi.org/10.3390/50300338 Find Other Styles Article Metrics No No Article Access Statistics For more information on the journal statistics, click here. Multiple requests from the same IP address are counted as one view.