We wish to report the discovery of high acaricidal activity of a new compound, 1,5-di-(2,4-dimethylphenyl)-3-methyl-1,3,5-triazapenta-l,4-diene (proposed common name azaform) (I; Ar = 2,4-dimethylphenyl, R = Me). It can be prepared in good yield in a ArN=CHOEt + ArN=CHNHR 2ArN=CHNHR -..* / k 2 R I ArN=CHNCH=NAr (I) CulO catalyst / ArNC + ArN=CHNHRnumber of ways, the main routes being shown above. The structure was confirmed by elemental analysis, molecular weight determination, i.r., n.m.r., U.V. and mass spectrometry. These synthetic methods appear to be applicable to a wide range of compounds with various substituents in the aromatic nucleus. 1,3,5-triazapenta-l74-dienes with different substituents in each ring were obtained by the use of the appropriate starting materials. Rather surprisingly, slow equilibration of these unsymmetrical compounds with the corresponding symmetrical 1,3,5-triazapenta-l ,4-dienes took place in the dry state, and this process was rapidly accelerated in solution.The new acaricide belongs to a class of hitherto little-known compounds. Earlier workerslaZ prepared a number of 2,4-diaryl-1,3,5-triazapenta-l,3-and 1 ,4-dienes by alternative methods, but these compounds (I) are among the first examples of 2,4-unsubstituted derivatives. A recent publication3 describes compounds in which Ar and R in formula I above are replaced by an aliphatic or cycloaliphatic grouping.
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