Bromine → Ethyl 5-oxocyclopent-1-ene-1-heptanoate
反応式
BrBr.C([C:8]1([CH2:14][CH2:15][CH2:16][CH2:17][CH2:18][CH2:19][C:20]([O:22][CH2:23][CH3:24])=[O:21])[CH2:12][CH2:11][CH2:10][C:9]1=[O:13])(OCC)=O>C(Cl)(Cl)Cl>[C:20]([CH2:19][CH2:18][CH2:17][CH2:16][CH2:15][CH2:14][C:8]1[C:9](=[O:13])[CH2:10][CH2:11][CH:12]=1)([O:22][CH2:23][CH3:24])=[O:21]参加物
4
実験手順
Under agitation at 20° , 48 g. of Br2, dissolved in 500 ml. of CHCl3, is added dropwise within 2 hours to a solution of 100 g. of 2-carbethoxy-2-(6-carbethoxyhexyl)-cyclopentanone in 1 l. of CHCl3. The solvent is distilled off, the residue is taken up in a mixture of 4 l. of ethanol, l kg. of H2SO4 (density: 1.84), and 100 ml. of H2O, refluxed for 18 hours under N2 and poured on 10 kg. of ice after cooling. The reaction mixture is extracted three times with respectively 5 l. of ether, the combined ether extracts are dried over Na2SO4, the solvent is distilled off, and chromatographic purification of the residue (silica gel/petroleum ether : ether =1 : 1) yields 2-(6-carbethoxyhexyl)- 2-cyclopentenone.