Microwave Radiation Applied in the N-Aryl-N′-Aminoеthylureas

The paper considers methods for the N-aryl-N'-aminoethylureas synthesis. The methods can be used as base products for the preparation of potential cytokinin active compounds with oxamate and oxamide functional groups. The previous studies showed that upon the interaction between aryl isocyanates and ethylenediamine, symmetric bisureas become the main reaction products, while the yield of the target 2-aminoethylureas is no more than 10 %. The high yield of N-aryl-N'-(oxamoylamino)ethylurea is also not provided by using one group aminoprotected ethylenediamine. Thus, when using Boc-protection, the yield of target products does not exceed 13 %. In this research, we used the methodology of microwave synthesis in acylation and aminolysis reactions. As a result, N-2-aminoethyl-N'-arylureas with various substituents in the aromatic ring were obtained in good yields. We compared the microwave radiation aminolysis of N,N'-bis(arylcarbamoyl)ethylenediamines, N-aryl-carbamoylimidazoles and diarylureas with ethylenediamine under microwave conditions. Findings of research show that reactions without microwaves proceed with the formation of only trace amounts of the target compounds, which are used for synthesis of structural analogs of phytoactive compounds, in the molecules of which carbamate and urea groups are replaced by oxamate ones

This work is supported by grants from the Russian Foundation for Basic Research (RFBR project no. 19-03-00492)

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