Reaction of chloropyridazin-3(2H)-ones with iodide. Part II.

Abstract

The reactions of 5-chloro-6-phenyl-,4,5-dichloro-6-phenyl-and 5-chloro-6-(2,4-dichlorophenyl)-2-methylpyridazin-3(2H)-ones with 57% aqueous hydrogen iodide or sodium iodide in dimethyl formamide, respectively, are described. Upon treatment of chloro compounds with 57% hydrogen iodide, besides nucleophilic substitution of chloro-by iodo substituent, subsequent hydrodeiodination also occurred. Thus, e.g. 4,5-dichloro-2-methyl-6-phenylpyridazin-3(2H)-one gave first 5-chloro-4-iodo-2-methyl-6-phenylpyridazin-3(2H)-one and in the next step, 5-chloro-2-methyl-6-phenylpyridazin-3(2H)-one. Similarly, treatment of 5-chloro-2-methyl-6-phenylpyridazin-3(2H)-one led to the formation of 5-iodo-2-methyl-6-phenylpyridazin-3(2H)-one and 2-methyl-6-phenylpyridazin-3(2H)-one. The structure of each new product was proved by 1 H, 13 C and partly by 15 N NMR spectroscopy.