2-甲基-2-羟基-1-苯基-1-丁酮的合成

首先由2-甲基丁酸、氯化亚砜,合成了2-甲基丁酰氯,其次,以无水三氯化铝为催化剂,苯与2-甲基丁酰氯反应合成了2-甲基-1-苯基-1-丁酮,当催化剂用量为22 g,2-甲基丁酰氯的滴加时间为1.5 h,苯与2-甲基丁酰氯物质量的比为5.0∶1时,收率为92.6%。最后在氢氧化钠水溶液中,以四氯化碳为氯化试剂,四丁基溴化铵为相转移催化剂,将2-甲基-1-苯基-1-丁酮直接氯代和水解制得2-甲基-2-羟基-1-苯基-1-丁酮。当四氯化碳的用量为12 mL,四丁基溴化铵用量为6 g,氢氧化钠浓度为17%,反应时间为6 h时,产品的收率可达90.3%。通过元素分析、红外光谱分析、质谱对产品进行了结构表征。

Synthesis of 2-Methyl-2-hydroxy-1-phenyl-l-butanone

First,2-methylbutyryl chloride was prepared from 2-methylbutyric acid and thionyl chloride.Second,2-methyl-1-phenyl-1-butanone was synthesized from benzene and 2-methylbutyryl chloride in the presence of anhydrous aluminum chloride as catalyst.Thirdly,2-methyl-2-hydroxy-1-phenyl-1-butanone was prepared by chlorination and hydrolysis of 2-methyl-1-phenyl-1-butanone in the presence of NaOH(aq) with CCl_4 as chlorinating agent and tetrabutyl ammonium bromide as phase transfer catalyst.The experimental results showed that the optimum conditions were as follows: anhydrous aluminum chloride was 22 g,reaction time was 1.5 h,dropwise time of 2-methylbutyryl chloride was 1.5 h,n(C_6H_6)/n(2-methylbutyryl chloride) was 5.0∶1.The yield of 2-methyl-1-phenyl-1-butanone was 92.6%.When CCl_4 was 12 mL,tetrabutyl ammonium bromide was 6 g,sodium hydroxide was 17%,and reaction time was 6 h,the yield of 2-methyl-2-hydroxy-1-phenyl-1-pentanone was 90.3%.The structure of the product was characterized by elemental analysis,IR and MS.