反应详情

Under nitrogen atmosphere 2-phenyl-5-trifluoromethyl-oxazole-4-carboxylic acid (288 mg, 1.12 mmol) was dissolved in a 4:1 mixture of dry DCM and MeOH (12.5 mL) and trimethylsilyl diazomethane (134 mg, 1.176 mmol; 2.0M solution in n-hexane) was added dropwise. After 10 min. stirring at room temperature excess trimethylsilyl diazomethane was destroyed by the addition of a few drops acetic acid. The solvent was evaporated to afford the crude methylester as a yellow solid which was redissolved in dry THF and nitrogen atmosphere. LiAlH4 (50 mg, 1.34 mmol) was added in several small portions and the resulting mixture was stirred at room temperature for 1.5 h. The mixture was cooled down to 0° C. and excess LiAlH4 was hydrolyzed by adding MeOH (5 mL), H2O (10 mL) and 2N aq. HCl (5 mL). After extracting with DCM the combined organic layers were dried (MgSO4) and evaporated under reduced pressure to afford the title compound as an oil. 1H NMR (400 MHz, CDCl3): δ 8.05-8.09 (d, 2H), 7.43-7.58 (m, 3H), 4.75 (s, 2H).

1. additionwas added dropwise
2. customwas destroyed by the addition of a few drops acetic acid
3. customThe solvent was evaporated
4. customto afford the crude methylester as a yellow solid which
5. temperatureThe mixture was cooled down to 0° C.
6. extractionAfter extracting with DCM the combined organic layers
7. dry with materialwere dried (MgSO4)
8. customevaporated under reduced pressure