HRID1951934

反应详情

EQUATION

反应方程式

HRID 1951934 的结构方程式

AUXILIARIES

试剂、催化剂与溶剂

2

PROCEDURE

实验过程

A 20 mL BIOTAGE® microwave vial and stir bar were oven dried and cooled under a stream of dry nitrogen. The vial was flushed with argon and charged with dichlorobis(triphenylphosphine)-palladium(II) (96 mg, 0.137 mmol) and dioxane (12 mL) followed by sparging with argon for several minutes. 2-Bromopyridine (0.217 mL, 2.28 mmol), ethyl 5-(tributylstannyl)isoxazole-3-carboxylate (980 mg, 2.28 mmol), and 1-butyl-3-methylimidazolium hexafluorophosphate (0.047 mL, 0.228 mmol) were added and sparging was continued for several minutes. The vial was sealed and processed in a BIOTAGE® microwave at 150° C. for 60 minutes. The solution was cooled, evaporated, and the residue was loaded onto a 120 g Isco silica gel cartridge, which was pre-equilibrated with hexanes, and then eluted with 0-50% EtOAc/Hexanes. The product fractions were evaporated to give a pale yellow oil, which solidified after being placed under high vacuum to afford ethyl 5-(pyridin-2-yl)isoxazole-3-carboxylate (212 mg, 0.972 mmol, 43% yield). The product had an HPLC retention. time=2.48 min.—Column: YMC S5 COMBISCREEN® 4.6×50 mm (4 min.); Solvent A=10% MeOH, 90% H2O, 0.1% TFA; Solvent B=90% MeOH, 10% H2O, 0.1% TFA. LC/MS M+1=219.1. 1H NMR (400 MHz, chloroform-d) δ ppm 1.42-1.48 (m, 3H), 4.49 (q, J=7.28 Hz, 2H), 7.31 (s, 1H), 7.39 (ddd, J=7.53, 4.89, 1.13 Hz, 1H), 7.87 (td, J=7.78, 1.76 Hz, 1H), 7.96 (d, J=7.78 Hz, 1H), and 8.73 (d, 1H).

WORKUP

后处理

  1. customdried
  2. temperaturecooled under a stream of dry nitrogen
  3. customThe vial was flushed with argon
  4. customby sparging with argon for several minutes
  5. customsparging
  6. waitwas continued for several minutes
  7. customThe vial was sealed
  8. temperatureThe solution was cooled
  9. customevaporated
  10. washeluted with 0-50% EtOAc/Hexanes
  11. customThe product fractions were evaporated
  12. customto give a pale yellow oil, which