[CH3:1][C:2]1[O:3][C:4]2[C:5](=[C:7]([OH:11])[CH:8]=[CH:9][CH:10]=2)[N:6]=1.[CH2:12]([O:14][C:15](=[O:19])[C:16]#[C:17][CH3:18])[CH3:13].C(=O)([O-])[O-].[K+].[K+]>O1CCCC1>[CH2:12]([O:14][C:15](=[O:19])/[CH:16]=[C:17](/[O:11][C:7]1[C:5]2[N:6]=[C:2]([CH3:1])[O:3][C:4]=2[CH:10]=[CH:9][CH:8]=1)\[CH3:18])[CH3:13]A mixture of 2-methyl-benzooxazol-4-ol (0.940 g, 6.30 mmol), ethyl-2-butynoate (4.24 g, 37.81 mmol) and potassium carbonate (0.956 g, 6.92 mmol) in tetrahydrofuran (20 mL) was placed in a sealed tube and heated at 100° C. for 5.5 h. The reaction mixture was cooled to room temperature, filtered and concentrated in vacuo. The residue was purified by ISCO Combiflash chromatography (Analogix SF-25, 2% to 15% ethyl acetate/hexanes) which afforded (E)-3-(2-methyl-benzooxazol-4-yloxy)-but-2-enoic acid ethyl ester (0.920 g, 56%) as a light yellow solid.
불러오는 중…
