A series of 2-substituted-4-arylamino-6-trichloromethyl-1, 3, 5-triazines is one of the most interesting chemical species for nitrification-inhibitory activity. This type of compounds has conventionally been obtained by the rather laborious processes via following reactions, i. e., hydroxylation of 2-substituted-4, 6-bis(trichloromethyl)-1, 3, 5-triazines to 2-substituted-4hydroxy-6-trichloromethyl-1, 3, 5-triazines, chlorination of the hydroxy-1, 3, 5-triazines to 2substituted-4-chloro-6-trichloromethyl-1, 3, 5-triazines, followed by substitution reaction of the chloro-1, 3, 5-triazines with arylamines. A new method has recently been found which permits the direct nucleophilic replacement of one trichloromethyl group attached to a 1, 3, 5-triazine ring with an arylamino group. The desired replacement reaction of the trichloromethyl by an arylamino group is accomplished in the present of tertiary amines such as triethylamine. By this method, a lot of biologically active 2-substituted-4-arylamino-6-trichloromethyl-1, 3, 5triazines can be synthesized from 2-substituted-4, 6-bis(trichloromethyl)-1, 3, 5-triazines.