Tert-butyl acetoacetate → HCID 68647637, compound

Participants

Reaction Steps

tert-Butyl acetoacetate (5.0 g, 32 mmol) is dissolved in ether (100 mL). Potassium bis(trimethylsilyl)amide (5.7 g, 29 mmol) is added slowly while stirring at room temperature. Then the mixture is concentrated and triturated with hexane. The precipitate is filtered and dried to yield crude potassium enolate 23 (4.6 g, 23 mmol, 81%). Enolate 23 (1.0 g, 5.0 mmol) is dissolved in MeCN (50 mL) and cooled to 0° C. Intermediate 16 (1.1 g, 4.2 mmol) dissolved in MeCN (10 mL) is added dropwise and the solution is stirred at 0° C. for 2 hours. The solvent is evaporated and the remainder is purified by column chromatography using a hexanes/EtOAc gradient to afford 3-(2-chloro-4-methoxycarbonylmethyl-phenyl)-5-methyl-isoxazole-4-carboxylic acid tert-butyl ester 24 as a white solid: 1H-NMR (400 MHz, CDCl3) δ=7.41 (d, J=1.5 Hz, 1H), 7.33 (d, J=7.8 Hz, 1H), 7.25 (dd, J=8.0 Hz, J=1.5 Hz, 1H), 3.69 (s, 3H), 3.65 (s, 2H), 2.73 (s, 3H), 1.28 (s, 9H). MS calculated for C18H21ClNO5 (M+H+) 366.1, found 366.4.

Provenance & Evidence