反应详情

To a solution of pyrimidine-4-carboxylic acid (261 mg, 2.00 mmol) and DIPEA (0.52 mL, 2.96 mmol) in DMF (8 mL) was added methyl isocyanoacetate (0.28 mL, 2.93 mmol) at rt. The resulting yellow solution was stirred at rt for 5 min and cooled to 0° C. DPPA (0.54 mL, 2.43 mmol) was then added and the resulting solution was stirred at 0° C. for 1 h and at rt for 30 min. Aq. sat. NaHCO3-solution was added and the mixture extracted with EtOAc (4×). The combined organic extracts were dried (Na2SO4), filtered and concentrated in vacuo. Purification by FC (hept/EtOAc 9:1 to 100% EtOAc) yielded methyl 5-(pyrimidin-4-yl)oxazole-4-carboxylate. LC-MS conditions A: tR=0.68 min, [M+H]+=206.43.

1. temperaturecooled to 0° C
2. stirringthe resulting solution was stirred at 0° C. for 1 h and at rt for 30 min
3. extractionthe mixture extracted with EtOAc (4×)
4. dry with materialThe combined organic extracts were dried (Na2SO4)
5. filtrationfiltered
6. concentrationconcentrated in vacuo
7. customPurification by FC (hept/EtOAc 9:1 to 100% EtOAc)