Ethyl Acetoacetate → Ethyl 2-acetyl-3-(dimethylamino)acrylate

Participants

Reaction Steps

To a solution of ethyl acetylacetate (6 g, 46 mmol) in benzene (100 mL) was slowly added a solution of dimethylformamide dimethylacetal (8.2 g, 69 mmol) in benzene (100 mL) at 25° C. After the addition was complete, the reddish mixture was heated at reflux for 1 h and then evaporated to dryness to give ethyl 2-dimethylaminomethylene-3-oxobutanoate (8.66 g) as a reddish oil. This product (3.25 g, 17 mmol) was allowed to react with 4-chlorophenylhydrazine hydrochloride (3.14 g, 17 mmol) in EtOH (50 mL) at reflux for 8 h. The mixture was evaporated to dryness and the product was isolated by flash chromatography to give ethyl 1-(4-chlorophenyl)-5-methyl-1H-pyrazole-4-carboxylate as a white solid (2.07 g, 46%): mp 55°-56° C.; 1H NMR (80 MHz, CDCl3) δ (TMS) 8.02 (s, 1H, pyrazole), 7.50 (d, J=9, 2H, arom), 7.34 (d, J=9, 2H, arom), 4.33 (q, J=7, 2H, OCH2), 2.56 (s, 3H, Me-pyrazole), 1.37 (t, J=7, 3H, OCH2CH3). Analysis calculated for C13H13ClN2O2 : C 58.99; H 4.95; N 10.58. Found: C 59.03; H 5.06; N 10.58.

Provenance & Evidence