Toluene → Ethyl 1-(7-ethoxy-7-oxoheptyl)-2-oxocyclopentane-1-carboxylate
Reaction equation
[K].[CH3:2][CH2:3][O:4][C:5]([CH:7]1[C:11](=[O:12])[CH2:10][CH2:9][CH2:8]1)=[O:6].Br[CH2:14][CH2:15][CH2:16][CH2:17][CH2:18][CH2:19][C:20]([OH:22])=[O:21].[C:23]1(C)C=CC=C[CH:24]=1>>[C:5]([C:7]1([CH2:14][CH2:15][CH2:16][CH2:17][CH2:18][CH2:19][C:20]([O:22][CH2:23][CH3:24])=[O:21])[CH2:8][CH2:9][CH2:10][C:11]1=[O:12])([O:4][CH2:3][CH3:2])=[O:6]Participants
5
Procedure
Under agitation, 500 g. of potassium salt of the ethyl ester of 2-oxocyclopentanecarboxylic acid is added to a boiling solution of 550 g. of the ethyl ester of 7-bromoenanthic acid in 6 l. of toluene; the mixture is further refluxed and, after one hour, another 250 g. of the potassium salt of the ethyl ester of 2-oxocyclopentanecarboxylic acid is added thereto. The reaction mixture is refluxed for another 24 hours, filtered after cooling, the solvent is distilled off, the residue is diluted with 3 l. of ether, washed with water, dried over Na2SO4, and the solvent is distilled off. After fractionation of the residue, 2-carbethoxy-2-(6-carbethoxyhexyl)-cyclopentanone is obtained as a colorless oil, b.p. = 165° (0.3 mm. Hg).