[Br:1][C:2]1[CH:11]=[N:10][C:9]2[NH:8][C:7](=[O:12])[CH2:6][O:5][C:4]=2[CH:3]=1.[Li]N([Si](C)(C)C)[Si](C)(C)[CH3:16].COS(OC)(=O)=O>C1COCC1>[CH3:16][N:8]1[C:7](=[O:12])[CH2:6][O:5][C:4]2[CH:3]=[C:2]([Br:1])[CH:11]=[N:10][C:9]1=2To a suspension of 5 g of 7-bromo-2H-pyrido[3,2-b]-1,4-oxazin-3(4H)-one (0.022 mole) in 90 ml of THF is added 24 ml of LiN(TMS)2 (0.024 mole) in THF. The homogenous solution is maintained under nitrogen at room temperature for 20 min., 3.03 g (0.024 mole) of dimethylsulfate is added and the reaction mixture allowed to stir overnight. The reaction mixture is then quenched with 20 ml of sat. ammonium chloride and extracted with 3×80 ml ethyl acetate. The ethyl acetate is then washed with 3×30 ml sat. ammonium chloride, dried over sodium sulfate and concentrated to obtain off white product which is used directly in the next step.
Wird geladen…
