反应详情

A mixture of methyl 2-fluoro-3-formylbenzoate (3.6 g, 19.9 mmol) from Step C above and hydroxy ethyl hydrazine (1.5 g, 19.9 mmol) in MeOH (16 mL) was irradiated with microwaves at 150° C. for 1.5 h. The reaction mixture was cooled and partitioned between H2O and ethyl acetate. The aqueous phase was extracted with additional ethyl acetate and then the combined organic extracts were dried (Na2SO4) filtered, concentrated and purified by column chromatography (silica gel, 70:30 hexanes/ethyl acetate) to afford methyl 1-(2-hydroxyethyl)-1H-indazole-7-carboxylate as a yellow solid (2.83 g, 65%): 1H NMR (500 MHz, CDCl3) δ 8.13 (s, 1H), 7.99 (d, J=7.5 Hz, 1H), 7.94 (d, J=8.0 Hz, 1H), 7.18 (t, J=8.5 Hz, 1H), 4.84 (t, J=5.0 Hz, 2H), 4.13-4.07 (m, 2H), 3.99 (s, 3H), 3.20-3.10 (m, 1H).

1. customwas irradiated with microwaves at 150° C. for 1.5 h
2. temperatureThe reaction mixture was cooled
3. custompartitioned between H2O and ethyl acetate
4. extractionThe aqueous phase was extracted with additional ethyl acetate
5. dry with materialthe combined organic extracts were dried (Na2SO4)
6. filtrationfiltered
7. concentrationconcentrated
8. custompurified by column chromatography (silica gel, 70:30 hexanes/ethyl acetate)