Sulfuric acid magnesium salt (1:1) → Azulene

Participants

Reaction Conditions

Reaction Steps

1,3-Azulenedicarboxaldehyde (600 mg) is dissolved in 6.5 ml of pyridine. Magnesium sulfate (1200 mg) and N-tert-butylhydroxylamine hydrochloride (1638 mg) is added to the solution. The mixture is heated with stirring to 95° C. under nitrogen and is stirred for 13 hours. Upon cooling to rt, the reaction mixture is poured into a separator funnel containing 60 ml of CHCl3 and 60 ml of sat aq. NaHCO3. The aqueous layer is separated and washed with three 30 ml portions of CHCl3. The combined organic layers are dried over anhydrous MgSO4, filtered, and evaporated to give the bis-nitrone 34 (940 mg, 89% yield) as dark green crystals. Oxidation potential equals 0.72 V vs SCE. 1H NMR (CDCl3): 10.35 (s, 1H), 8.65 (d, 2H, J=10 Hz) 8.11 (s, 2H), 7.68 (t, 1H, J=10 Hz), 7.32 (t, 2H, J=10 Hz), 1.67 (s, 18H). 13C NMR (CDCl3): 139.9, 135.0, 134.2, 125.8, 125.6, 123.2, 120.5, 69.8, 28.4. IR (thin film): 3052, 2972, 1644, 1564, 1452, 1404, 1356, 1261, 1196, 1124, 1052, and 892 cm−1.

Provenance & Evidence