[Mg].Br[C:3]1[CH:8]=[CH:7][C:6]([Br:9])=[CH:5][CH:4]=1.C[Si](C)(C)[O:12][C:13]1[CH:14]=[CH:15][C:16](Cl)=[N:17][CH:18]=1.C(=O)([O-])O.[Na+]>C(OCC)C.CC(P(C1C=CC=CC=1)C1C=CC=CC=1)C.C1C=CC(PC2C=CC=CC=2)=CC=1.[Cl-].[Ni].O1CCCC1>[OH:12][C:13]1[CH:14]=[CH:15][C:16]([C:3]2[CH:8]=[CH:7][C:6]([Br:9])=[CH:5][CH:4]=2)=[N:17][CH:18]=1A Grignard reagent solution prepared from 0.8 g of magnesium, 8.0 g of 1,4-dibromobenzene and 50 ml of tetrahydrofuran was added dropwise at 0°-5° C. within 30 minutes to a mixture of 6.6 g of 5-trimethylsilyloxy-2-chloropyridine, 75 ml of tetrahydrofuran and 0.4 g of 1,3-bis(diphenylphosphino)-propanenickel(II) chloride. The reaction mixture was stirred for 3 hours, left to stand overnight, then adjusted to pH 8 with aqueous sodium hydrogen carbonate solution and diluted with diethyl ether. The organic phase was washed neutral with water, dried over sodium sulfate and concentrated. Chromatographic purification of the residue on silica gel with hexane/ethyl acetate (vol. 4:1) yielded 5.5 g of 5-hydroxy-2-(4-bromophenyl)-pyridine.
読み込み中…
