1960 年 80 巻 1 号 p. 41-45
5-Halofurfural formed orange crystalline substance by reaction with aniline and the structure of this product has been assumed as 2-bis (phenylarnino) methyl-5-halo-furan (A). Reëxamination of this reaction indicated that the halogen in this product is ionic and reacts quite easily with silver nitrate and alkali. The present workers therefore deny the formula (A) and propose the structure of N-(5-anilinofurfurylidene)-aniline hydrochloride (B). Treatment of (B) with alkali gives dehydrohalogenated substance as yellow crystals, m. p. 147°(decomp.), and its base would be represented by formula (C). Application of hydrochloric or hydrobromic acid to (C) results in instantaneous conversion of the yellow crystals to orange (B), while application of hydriodic acid results in the formation of the hydriodide of (B), which is considered to be formed from 5-iodofurfural and aniline. The foregoing facts were further confirmed by application of various aromatic primary amines other than aniline to 5-chloro- and 5-bromo-furfural. Application of phenylhydrazine to the (C)-type compounds listed in Table IV afforded the 5-arylaminofurfural phenylhydrazones shown in Table V. Treatment of (C) with sulfanilic acid afforded N-(5-anilinofurfurylidene) sulfanilic acids. It is considered that this kind of substitution reaction gives evidence to the structure of (B) and (C).