Organic Chemistry: Current Research
Open Access

Aza-michael reaction through azoles and further transformation of obtained adducts

10^th European Organic Chemistry Congress

March 21-22, 2019 | Rome, Italy

H. N. Khachatryan and O. S. Attaryan

Institute of Organic Chemistry, Scientific-Technological Center of Organic and Pharmaceutical Chemistry NAS RA, Armenia

Posters & Accepted Abstracts: Organic Chem Curr Res

Abstract :

The Aza-Michael reaction of azoles (pyrazole, 3(5)-methyl-pyrazole, 3,5-dimethylpyrazole, 1,2,4-triazole, imidazole, tetrazole) with methylvinilketone was carried out in the absence of a catalyst. It has been shown that the acidity of the azoles plays a significant role in the reaction. Moreover, the interaction of pyrazoles (pyrazole, 3(5)-methylpyrazole, 3,5-dimethyl-pyrazole) with crotonic aldehyde in this system has also been studied. It has been shown that the interaction of corresponding pyrazoles with crotonic aldehyde in this system was succeeded and in fact 1:2 reagent/substrate molar ratio was providing the high yields of the obtained products (86-91 %). Despite the expectations the interaction of the aforementioned pyrazoles with crotonic acid in the absence of catalyst and solvent, proceeds more readily than with crotonaldehyde. A similar phenomenon was also observed with the interaction of 3,5-dimethylpyrazole and crotonic acid ethyl ester. The aza-Michael reaction of pyrazoles with maleic acid proceeds through the processing of the π-complex, then the σ-complex and carries out to the corresponding additives with yields of about 80-90 %. Furthermore, in aza-Michael reaction the transition from activated double bond to isolated double bond was performed in particular to allyl cyanide. The results were conditioned to the isomerization of double bond. It is expected that the pyrazoles do not interact with allylcinid even under prolonged heating. However, the reaction can proceed if the temperature is incre-ased to 200-220oC. The complexation properties of the obtained adducts of aza-Michael reaction with PdCl2 has also been investigated. The corresponding adducts could form complexes with PdCl2 only if the second coordination center in the molecule is provided. It has been studied the behavior of 1-(2-aminoethyl)-3,5-dimethylpyrazole and methylacrilate in the aza-Michael reaction. In order to synthesize the exocyclic compounds of the pyrazole series, the 3-(3,5-dimethyl-1H-pyrazole-1-yl)butanal was considered in the oxidation and reduction reactions.