反应详情

温度

135 °C

To N-benzyl-N′-(4-fluoro-2-methyl-phenyl)-ethane-1,2-diamine (15.1 g) in toluene (150 mL) was added N,N-diisopropylethylamine (33.8 mL) and 2,3-dibromopropionic acid ethyl ester (25.61 mL) in toluene (350 mL). The reaction mixture was heated to 135° C. for 18 h, cooled to room temperature, and the precipitated solid was removed by filtration. The solution was concentrated, and the crude material was redissolved in TBME and washed with an aqueous 2M solution of Na2CO3 and brine, dried (Na2SO4), filtered and evaporated. Chromatography (SiO2, n-heptane/ethyl acetate 97:3) gave 4-benzyl-1-(4-fluoro-2-methyl-phenyl)-piperazine-2-carboxylic acid ethyl ester (5.5 g) as yellow oil, MS: 357.3 ([M+H]+) and 1-benzyl-4-(4-fluoro-2-methyl-phenyl)-piperazine-2-carboxylic acid ethyl ester (3.3 g) as yellow oil, MS: 357.1 ([M+H]+).

1. temperaturecooled to room temperature
2. customthe precipitated solid was removed by filtration
3. concentrationThe solution was concentrated
4. dissolutionthe crude material was redissolved in TBME
5. washwashed with an aqueous 2M solution of Na2CO3 and brine
6. dry with materialdried (Na2SO4)
7. filtrationfiltered
8. customevaporated