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The Michael-Type Addition of 1-Cyanoacetyl-3,5-Dimethylpyrazole to Arylmethylenecyanoacetamides
* 1 , * 2, 3, 4
1  Federal State Unitary Enterprise «Research Institute of Chemical Reactants and Ultrapure Compounds (IREA)», 3 Bogorodsky Shaft, Moscow 107076, Russia
2  Kuban State University, 149 Stavropolskaya Str., Krasnodar 350040, Russian Federation
3  ChemEx Lab, Vladimir Dal’ Lugansk National University, Lugansk, 91034 Russia.
4  North-Caucasus Federal University, 1 Pushkina St., 355009 Stavropol, Russian Federation

Abstract: Abstract: The Et3N-promoted reaction of (E)-3-aryl-2-cyanoacrylamides (arylmethylenecyanoacetamides) with 1-cyanoacetyl-3,5-dimethylpyrazole was thoroughly studied. It was found that either triethylammonium 4-aryl-3,5-dicyano-6-oxo-1,4,5,6-tetrahydropyridine-2-olates 1 (salts of Guareschi imides) or their oxidation products – triethylammonium 4-aryl-3,5-dicyano-6-oxo-1,6-dihydropyridine-2-olates 2 were formed, depending on the nature of substituents in the 3-aryl fragment of starting acrylamides. Thus, when Ar = ortho-, meta-substituted phenyl or hetaryl such as 2-furyl, 3-thienyl etc., only Guareschi imides salts 1 were obtained in good to excellent yields. In the case of para-substituted or unsubstituted phenyl, pyridine-2-olates 2 were isolated as major products due to fast oxidation of Guareschi intermediates. The influence of reaction conditions and the nature of the base on the structure of final products is discussed.