Dimethylformamide dimethyl acetal → 3-(Dimethylaminomethylidene)-6-methylpyran-2,4-dione

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Reaction Steps

A suspension of 2-hydroxy-6-methyl-4H-pyran-4-one (23.92 g, 0.189 mmol) and dimethylformamide dimethyl acetal (45.2 mL, 0.34 mmol) in toluene (100 mL) was stirred at room temperature for 4 hours and concentrated to provide 25.8 g (75%) of the desired product of sufficient purity for subsequent use. MS (DCI/NH3) m/z 182 (M+H)+; 1H NMR (CDCl3) δ 8.22 (s, 1H), 5.67 (s, 1H), 3.47 (s, 3H), 3.39 (s, 3H), 2.13 (s, 3H).

Provenance & Evidence