Oxalyl chloride → HCID 67574073, compound

Participants

Reaction Conditions

Reaction Steps

To a mixture of 0.40 g of the title compound of Step D in 25 mL of tetrahydrofuran was added 0.34 mL of oxalyl chloride (purchased from Aldrich Chemical Co.) and 2 drops of N,N-dimethylformamide. The mixture was refluxed for 2 h and was then concentrated under reduced pressure to dryness. To the resulting residue was added 25 mL of tetrahydrofuran and evaporated to dryness again. Another 25 mL of tetrahydrofuran was added to the residue and the solution was cooled to about 0° C. To this mixture was added 0.16 g of 1,3-cyclohexanedione (purchased from Aldrich Chemical Co.) followed by addition of 0.52 mL of triethylamine. The mixture was stirred overnight at room temperature. To the reaction mixture was added saturated aqueous sodium bicarbonate and the mixture was extracted with methylene chloride. The combined organic extracts were dried over MgSO4, filtered, and concentrated under reduced pressure to dryness. Chromatography of the crude product on silica gel eluting with a mixture of hexanes:ethyl acetate (8:1 and then 4:1) yielded 0.21 g of the title compound of Step E as a yellow solid melting at 126°-130° C. 1H NMR (CDCl3): δ 2.18 (m, 2H), 2.49 (t, 2H), 2.64 (s, 3H), 2.72 (t, 2H), 2.90 (t, 2H), 3.06 (s, 3H), 3.52 (t, 2H), 6.07 (s, 1H), 7.50 (d, 1H), 7.62 (s, 1H), 7.70 (d, 1H).

Provenance & Evidence