1-(5-bromo-2-fluorophenyl)butan-1-one

Conditions: temp:65.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To 1-(5-bromo-2-fluorophenyl)butan-1-one (2.0 g, 8.1 mmol) in THF, anhydrous hydrazine (11 mL) in THF was added and heated at reflux (60-70° C.) for 5-6 hours. Xylene was added to the reaction mixture and heated at reflux for 20-24 hours. The reaction mixture was concentrated to give a crude product, which was purified by column chromatography using 15% ethyl acetate/pet-ether as eluents to afford 5-bromo-3-propyl-1H-indazole (1.02 g, 52.3%) as a solid. 1H NMR (CDCl3): δ 7.9 (s, 1H), 7.4 (d, 1H), 7.3 (d, 1H), 2.9 (t, 2H), 1.8 (q, 2H), 1.0 (t, 3H). heated heated at reflux for 20-24 hours The reaction mixture was concentrated to give a crude product, which was purified by column chromatography

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 1-(5-bromo-2-fluoro-phenyl)-butan-1-ol (6.2 g, 25 mmol) in dry CH2Cl2 (60 mL) were added pyridinium dichromate (19.0 g, 50.3 mmol) and molecular sieves powder (1.24 g) at room temperature and stirred overnight. The reaction mixture was filtered through diatomaceous earth and washed with diethyl ether (200 mL). The combined CH2Cl2 and ether layers were dried over anhydrous Na2SO4, filtered and concentrated to give a crude product, which was purified by column chromatography using 5% ethyl acetate/pet-ether as eluents to afford 1-(5-bromo-2-fluorophenyl)butan-1-one (4.6 g, 75%) as a syrup. 1H NMR (CDCl3): δ 8.0 (m, 1H), 7.5-7.6 (m, 1H), 7.0 (t, 1H), 2.9-3.0 (m, 2H), 1.7 (q, 2H), 1.0 (t, 3H). The reaction mixture was filtered through diatomaceous earth washed with diethyl ether (200 mL) The combined CH2Cl2 and ether layers were dried over anhydrous Na2SO4 filtered concentrated to give a crude product, which was purified by column chromatography