The Reaction of Tropolones with Phosphorus Oxychloride. The Rearrangement Reaction of 5-Arylazo-2-chlorotropones to 2-Aryl-4, 5-dichloroindazoles
作者:Katsuo Kikuchi、Masaki Yagi、Kunio Takada
DOI:10.1246/bcsj.41.424
日期:1968.2
The reaction of tropolone and phosphorus oxychloride gave 2-chlorotropone. Similarly, 5-cyano-, 5-nitro, and 5-chlorotropolones afforded the corresponding 2-chlorotropone derivatives in moderate yields. 3-Cyanotropolone gave 2-chloro-7-cyanotropone, while 3-phenyltropolone afforded only 2-chloro-3-phenylbenzaldehyde. When 3-bromotropolone and 5-bromotropolone were treated similarly, 2, 7-dichloro- and 2, 5-dichlorotropones were obtained respectively, with a facile halogen exchange. The further treatment of 2, 5-dichlorotropone with phosphorus oxychloride afforded 2, 5-dichloro- and 3,4-dichlorobenzaldehydes. The reaction of 5-p-tolylazo-, 5-phenylazo-, and 5-p-nitrophenylazotropolones with phosphorus oxychloride gave the corresponding 5-arylazo-2-chlorotropones, which, on further treatment with an excess of the reagent, gave 2-aryl-4, 5-dichloroindazoles.
倍氯酮与磷氧氯化物的反应生成了2-氯倍酮。同样,5-氰基、5-硝基和5-氯倍氯酮也分别获得了相应的2-氯倍酮衍生物,产率适中。3-氰基倍氯酮生成了2-氯-7-氰基倍酮,而3-苯基倍氯酮则仅获得了2-氯-3-苯基苯甲醛。当3-溴倍氯酮和5-溴倍氯酮以类似方式处理时,分别得到2,7-二氯和2,5-二氯倍酮,伴随简单的卤素交换。进一步用磷氧氯化物处理2,5-二氯倍酮,得到2,5-二氯和3,4-二氯苯甲醛。5-p-苯基偶氮、5-苯基偶氮和5-p-硝基苯基偶氮倍酮与磷氧氯化物的反应生成了相应的5-芳基偶氮-2-氯倍酮,经过进一步处理后与过量的试剂反应,得到2-芳基-4,5-二氯吲唑。