Derivatives of 1,3,5-oxadiazine are of interest to pharmacy, medicine, and agriculture as potential biologically active substances. These compounds have found wide application in organic synthesis and supramolecular chemistry. In this paper, we discuss and compare the effectiveness of two approaches to the dehydrosulfurization of 4-chloro-N-(2,2,2-trichloro-1-(3-arylthioureido)ethyl)benzamides resulting in the formation of 6-(4-chlorophenyl)-N-aryl-4-(trichloromethyl)-4H-1,3,5-oxadiazin-2-amines. Dicyclohexylcarbodiimide (DCC) or a mixture of iodine with triethylamine was used as a dehydrosulfurizing agent. It is shown that in the case of using DCC, the target products are predominantly formed in high yields. However, the use of the I₂+Et₃N mixture made it possible to obtain several new compounds of this class, which could not be obtained under the DCC action. The structure of all new compounds was confirmed by ¹Н and ¹³С NMR spectroscopy data.