Teruomi Jojima

Herbicidal Activity of Some Pyridazine Derivatives:Part I. Pyridazyl Phenyl Ethers

Herbicidal activity of some 50 pyridazyl ethers was evaluated. Among them, 3-chloro-6-(2-phenylphenoxy)-, 3-chloro-6-(2,6-dichlorophenoxy)-, 3-chloro-6-(3-methoxyphenoxy)- and 3-chloro-6-(4-methoxyphenoxy)-pyridazines showed conspicuous effectiveness on radish and millet in pre-emergence test, whereas postemergent activity of the compounds tested was not so remarkable in general. Relationships between herbicidal activity and chemical structure are discussed.

Syntheses of Pyridazine Derivatives as Herbicides:Part II. Preparation of 3-Halo- and 3-Anilino-6-phenoxypyridazines

Various 3-halo-6-phenoxypyridazines, with or without nitro groups on their benzene rings, and 3-anilino-6-phenoxypyridazines were prepared together with some related compounds to be evaluated as herbicides. Ultraviolet spectra of some nitrophenoxypyridazines thus obtained were also examined.

Herbicidal Activity of Some Pyridazine Derivatives: Part II. 3-Halo- and 3-Anilino-6-phenoxypyridazines and Related Compounds

Pre-emergent herbicidal activities of various 3-halo-6-phenoxypyridazines, with or without nitro groups on their benzene rings, and 3-anilino-6-phenoxypyridazines were examined along with those of related compounds. Among them, 3-bromo-6-(2′-phenylphenoxy)-, 3-chloro-6-(3′-nitrophenoxy)- and 3-chloro-6-anilino-pyridazines showed rather high herbicidal effects to radish and millet. On the other hand, some pyridazine derivatives especially 3-anilino-6-benzyloxy- and 3-(3′-chloroanilino)-6-phenoxy-pyridazines promoted shoot growth of millet.