Synthesis and biological activity of 1-(4-methyl-1,2,3-selenadiazol-5-yl)-3-arylureas and their <i>N</i> -chloroacetyl derivatives

This study presents a simple and convenient approach to the synthesis of 1-(4-methyl-1,2,3-selenadiazol-5-yl)-3-arylureas and (Z)-1-(2-(2-chloroacetyl)-4-methyl-1,2,3-selenadiazol-5(2H)-ylidene)-3-arylurea. The crystal structure of 3 compounds was studied, and it was shown that they possess pseudoheterocyclic system Se(1)C(5)N(1)C(6)O(2). The results of evaluating the fungicidal activity of all the obtained substances against 3 phytopathogenic fungi and the effect of 6 compounds on seed germination and development of cucumber seedlings in comparison with TDZ are presented. Compound 3b exhibited moderate activity (47.21 ± 0.43%) against S. sclerotiorum. Additionally, 1,2,3-selenadiazol-5-ylureas 2a and 2d inhibited root and stem elongation and lateral root formation in cucumber seedlings, demonstrating effects similar to those of TDZ. These findings suggest that further study of the growth-regulating properties of compounds 2a and 2d is warranted.