1,3-Cyclohexanedione → HCID 70421324, compound

Participants

Reaction Steps

To a mechanically stirred solution of 1,2-cyclopentanedione-2-oxime (25.0 g, 0.22 mol) and 1,3-cyclohexanedione (25.0 g, 0.22 mol) in 70% acetic acid (250 mL) was added zinc dust (43.0 g, 0.66 g-atom) in about 5-g portions (moderately exothermic) over a 30 minute period. After the addition, the mixture was heated to reflux for 2 hours and was then cooled to room temperature. The solution was decanted from excess zinc and poured into ice water (250 mL). The mixture was extracted with dichloromethane (1×200 mL, 2×100 mL) and the combined extracts were washed with saturated sodium bicarbonate to neutrality, then washed with brine, and dried (Na2SO4). The solution was concentrated to about 1/4 the original volume, whereupon the title cyclopent[b]indolone (8.3 g) separated as a light tan solid: mp 236°-238° C. (recrystallized from ethyl acetate); IR (KBr) 3210 (NH), 1620 cm-1 (C=O); NMR (CDCl3) δ 2.07 (m, 2, CH2), 2.30-2.90 (m, 10, CH2), 10.17 (br s, 1, NH); MS m/e 175 (M+). Anal. Calcd for C11H13NO: C, 75.40; H, 7.48; N, 7.99. Found: C, 75.36; H, 7.38; N, 7.84.

Provenance & Evidence