反应详情

A solution of methyl 5-ethyl-4-(1-methyl-1H-pyrazol-5-yl)-2-furancarboxylate (950 mg, 4.06 mmol) and N-chlorosuccinimide (542 mg, 4.06 mmol) in tetrahydrofuran (20 ml) was stirred in a sealed tube for 1 h at 70° C. 6N sodium hydroxide (13.5 ml, 81 mmol) was added in one portion and the solution stirred an additional 1 h. The reaction mixture was then partitioned between H2O-DCM and the pH of the aqueous phase was adjusted to ˜4 and washed several times with DCM. The combined organic fractions were dried over Na2SO4, concentrated and used directly without further purification yielding 4-(4-chloro-1-methyl-1H-pyrazol-5-yl)-5-ethyl-2-furancarboxylic acid (683 mg, 2.55 mmol, 62.8% yield) as a yellow oil: LCMS (ES) m/e 254, 256 (M, M+2)+.

1. customThe reaction mixture was then partitioned between H2O-DCM
2. washwashed several times with DCM
3. dry with materialThe combined organic fractions were dried over Na2SO4
4. concentrationconcentrated
5. customused directly without further purification