Dimedone → 3,6,6-trimethyl-6,7-dihydro-1H-indol-4(5H)-one

Reaktionsgleichung

[CH3:1][C:2](/[CH:4]=[N:5]/O)=O.[CH3:7][C:8]1([CH3:16])[CH2:13][C:12](=O)[CH2:11][C:10](=[O:15])[CH2:9]1>OC(C)=O.O.[Zn]>[CH3:1][C:2]1[C:11]2[C:10](=[O:15])[CH2:9][C:8]([CH3:7])([CH3:16])[CH2:13][C:12]=2[NH:5][CH:4]=1

Komponenten

Versuchsvorschrift

To a solution of anti-pyruvic aldehyde-1-oxime (10 g, 1 eq) and 5,5-dimethyl-1,3-cyclohexanedione (16.1 g, 1 eq) in HOAc—H2O (7:3, 200 mL) was added zinc powder (14.95 g, 2 eq) slowly with cooling by a water bath at room temperature. The mixture then was refluxed overnight, concentrated to dryness, partitioned between brine (300 mL) and dichloromethane (300 mL). The pH was adjusted to ca. 6 with saturated aqueous NaHCO3, then the mixture was extracted with dichloromethane (3×200 mL). The organic layers were combined, dried over Na2SO4, filtered, concentrated. The crude product was purified by flash chromatography eluting with 5% ethyl acetate in dichloromethane. The combined organic fractions were concentrated, triturated in ether-hexane (2:1) for 1 hour, then filtered, washed with hexane to give the pure title compound (9 g, 45% yield) as a solid. LCMS m/z: (M+H)=178.1.