[C:1]([CH:4]([CH2:8][CH2:9][C:10](=[O:12])[CH3:11])[C:5](=[O:7])[CH3:6])(=[O:3])[CH3:2].[C:13]([O:17][CH2:18][CH3:19])(=[O:16])[CH:14]=[CH2:15].C(O)(=O)C>N12CCCN=C1CCCCC2.C(OCC)C>[CH2:18]([O:17][C:13](=[O:16])[CH2:14][CH2:15][C:4]([C:5](=[O:7])[CH3:6])([C:1](=[O:3])[CH3:2])[CH2:8][CH2:9][C:10](=[O:12])[CH3:11])[CH3:19]10.2 g of 3-acetyl-2,6-heptandione and 5 drops of 1,8-diazabicyclo-[5.4.0]-undec-7-ene were mixed, and 9 g of ethyl acrylate was added dropwise over 15 minutes. After stirring for 16 hours, the base was neutralized with acetic acid, 30 ml of diethyl ether was added, and the solution was extracted with sodium carbonate solution and water. Fractional distillation of the dry organic layer yielded 9.3 g of 4,4-diacetyl-7-oxo-octanoic-ethyl ester (boiling point: 136° C./0.02 mbar; purity: 81%; colorless).
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