A practical procedure for synthesis of a new uricosuric agent, 5-chloro-7, 8-dihydro-3-phenylfuro[2, 3-g]-1, 2-benzisoxazole-7-carboxylic acid (1, AA-193) is described, which starts from 2, 5-dichlorophenol (3b) and involves 5-chloro-6-hydroxy-3-phenyl-1, 2-benzisoxazole (2) as the key intermediate. Successive treatment of 3b with benzoyl chloride-aluminum chloride (AlCl3) and hot ethanolic sodium hydroxide gives 4-benzoyl-2, 5-dichlorophenol (8, 61%), which is oximated with hydroxylamine hydrochloride and then transformed into the benzisoxazole 2 (88%) with potassium hydroxide in N, N-dimethylformamide (DMF) (method C). The reaction of 2 with aqueous formaldehyde and dimethylamine affords the Mannich base 11a (97%), which is treated with a sulfonium ylide 12, 14 or 15 followed by heating with sodium hydroxide (NaOH) in ethanol (EtOH) to give 1 in high yield (method E).
一种合成新型
尿酸排泄剂5-
氯-7, 8-二氢-
3-苯基呋喃[2, 3-g]-1, 2-苯
异噁唑-7-
羧酸(1,AA-193)的实用程序被描述,该程序以2, 5-二
氯酚(3b)为起始物,并以5-
氯-6-羟基-3-苯基-1, 2-苯
异噁唑(2)作为关键中间体。3b依次与
苯甲酰氯-
氯化铝(
AlCl3)和热
乙醇钠氢氧化物反应,得到4-苯甲酰-2, 5-二
氯酚(8,61%),该化合物与氢氧化
铵反应后,再用
氢氧化钾在N, N-二甲基甲酰胺(
DMF)中转化为苯
异噁唑2(88%)(C法)。化合物2与
水溶性
甲醛和
二甲胺反应生成Mannich碱11a(97%),然后与亚磺基阳离子12、14或15反应,随后在
乙醇(EtOH)中与
氢氧化钠(NaOH)加热反应,最终高产率获得化合物1(E法)。