反应详情

A solution of commercially available 4-methyl-3-trifluoromethylbenzoic acid (24.5 g, 120 mmol) and conc. sulfuric acid (6.5 ml) in dry ethanol (245 ml) is refluxed for 23 h. After reaching room temperature the solvent is evaporated and the residue is neutralized by addition of saturated aqueous NaHCO3 solution. The mixture is extracted with ethyl acetate (3×40 ml). The organic extracts are combined, dried over Na2SO4 and evaporated to dryness to afford a pale yellow oil: HPLC: tR=7.15 min (purity: >96%, gradient A), ESI-MS: 233.3 [MH]+.

1. customAfter reaching room temperature
2. customis evaporated
3. additionthe residue is neutralized by addition of saturated aqueous NaHCO3 solution
4. extractionThe mixture is extracted with ethyl acetate (3×40 ml)
5. dry with materialdried over Na2SO4
6. customevaporated to dryness
7. customto afford a pale yellow oil