反应详情

To a solution of 3-iodo-1-methyl-1H-pyrazole (378 mg, 1.82 mmol) in dry DCM (15 mL) at 0° C. under an atmosphere of nitrogen, was introduced ethylmagnesium bromide (2.0 mL of a 1.0M solution in THF, 2.0 mmol). After 30 minutes at 0° C., the reaction mixture was warmed to RT for 15 minutes, then introduced to a solution of 4-(trimethylsilyl)but-3-yn-2-one (0.37 ml, 2.18 mmol) in dry DCM (5 ml) at 0° C. under an atmosphere of nitrogen. The reaction mixture was warmed to RT for 16 hr. Following addition of saturated aqueous ammonium chloride (5 ml), the reaction mixture was extracted with DCM (3×5 mL extractions). The combined organic extracts were dried (Na2SO4), filtered and concentrated in vacuo. Purification of the residue by silica gel flash column chromatography (heptane/EtOAc gradient) furnished the title compound as an orange-brown oil: 1H NMR (500 MHz, CDCl3) delta 0.15 (9H, d, J=3.5 Hz), 1.82 (3H, s), 3.18 (1H, s), 3.86 (3H, s), 6.28 (1H, d, J=2.2 Hz), 7.26 (1H, d, J=2.2 Hz); LC-MS: m/z=+222.95 (M+H)+.

1. temperatureThe reaction mixture was warmed to RT for 16 hr
2. extractionthe reaction mixture was extracted with DCM (3×5 mL extractions)
3. dry with materialThe combined organic extracts were dried (Na2SO4)
4. filtrationfiltered
5. concentrationconcentrated in vacuo
6. customPurification of the residue by silica gel flash column chromatography (heptane/EtOAc gradient)