Methanol → HCID 10953983, compound

Participants

Reaction Steps

To a solution of 2 g (0.0158 mol) of 2,3-dimethylmaleic anhydride in 40 mL of methanol was added 0.2 mL of concentrated sulfuric acid. After refluxing for 7 days, the solution was diluted with 100 mL of methylene chloride, neutralized with aqueous sodium bicarbonate solution. The methylene chloride layer was washed with 30 mL of brine, the aqueous layer was extracted with methylene chloride four times (30 mL twice and 15 mL twice). The combined methylene chloride layer and extracts were dried over anhydrous magnesium sulfate, concentrated to give 2.11 g of crude product. 1H NMR check indicated about 25% of starting material existing, the crude mixture with 0.2 mL of concentrated sulfuric acid in 40 mL of methanol was heated at reflux again for 5 days. The solution was concentrated until 30% of methanol was left, neutralized with saturated sodium bicarbonate aqueous solution, followed by addition of 30 mL of brine solution, and the mixture was extracted with ethyl acetate four times (100 mL once, 30 mL three times). The combined ethyl acetate extracts were dried over anhydrous magnesium sulfate, concentrated to give 3.26 g of crude product 21 (˜100% yield). It was of satisfactory purity for the next step. 1H NMR (CDCl3) d 3.77 (s, 6H, OMe), 1.95 (s, 6H, Me)

Provenance & Evidence