反应详情

Oxalyl chloride (2.6 ml, 30 mmol) was added slowly to a solution of 4-(2-carboxy-ethyl)-3-methyl-benzoic acid methyl ester from Example E30.3 (5.33 g, 24 mmol) in di-chloromethane (60 ml) and few drops of DMF at 0° C. The mixture was stirred for 2 h at room temperature then concentrated in vacuo and azeotroped with toluene. The residue was dissolved in dichloromethane (30 ml) and added to a solution of 1-(3,3-dimethyl-butyl)-piperazine hydrochloride from Example E4 (6.3 g, 26 mmol) in dichloromethane (45 ml) and DIEA (17 ml, 96 mmol) at 0° C. The mixture was stirred for 1 h at room temperature then concentrated in vacuo. The residue was purified by flash chromatography on silica gel (eluant; 5% methanol:95% dichloromethane) to yield the title compound (8.5 g, 96%).

1. customat 0° C
2. concentrationthen concentrated in vacuo
3. customazeotroped with toluene
4. dissolutionThe residue was dissolved in dichloromethane (30 ml)
5. stirringThe mixture was stirred for 1 h at room temperature
6. concentrationthen concentrated in vacuo
7. customThe residue was purified by flash chromatography on silica gel (eluant; 5% methanol:95% dichloromethane)