[CH3:1][C:2]1[CH:7]=[CH:6][C:5]([CH3:8])=[N+:4]([O-])[C:3]=1[C:10]#[N:11].C(=O)(O)[O-].[Na+].[C:17]([O:20]C(=O)C)(=[O:19])[CH3:18]>>[C:17]([O:20][CH2:8][C:5]1[CH:6]=[CH:7][C:2]([CH3:1])=[C:3]([C:10]#[N:11])[N:4]=1)(=[O:19])[CH3:18]To acetic anhydride (20 ml) at 120° was added 3,6-dimethyl-2-pyridine-carbonitrile 1-oxide (5.28 g) and the solution heated at 120° for 5 minutes then under reflux for 2 hours. After cooling the solution was added to ice (ca. 150 g) and the mixture neutralized with sodium bicarbonate. It was extracted with ether (170 ml then 2×75 ml) and the combined extracts washed with brine (60 ml), dried (MgSO4) and concentrated in vacuo. The residue was purified by Biotage chromatography eluting with 2:1 hexane:ethyl acetate to afford the title compound (3.62 g, 67%) as a pale yellow oil
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