Ammonium Hydroxide → 5-bromo-1H-indazole-3-carbonitrile

Temperature

-50 °C

To a cooled solution of (2-amino-5-bromophenyl)acetonitrile (11 g, 52 mmol) in concentrated hydrochloric acid (110 mL) at −50° C., a solution of sodium nitrite (3.9 g, 57 mmol) in water (20 mL) was added slowly. After the addition, the mixture was stirred at −50° C. for 2 h. The mixture was neutralized with 33% ammonium hydroxide at 0° C. and extracted with ethyl acetate (3×100 mL). The combined organic layers were washed with saturated sodium chloride (100 mL), dried over anhydrous sodium sulfate and concentrated. The obtained crude product was purified by column chromatography (100-200 mesh silica gel) using 10% ethyl acetate in petroleum ether as eluent to afford 5-bromo-3-cyanoindazole (7 g, 60%) as a solid. 1HNMR (CDCl3) δ ppm 10.7 (br, 1H), 8.1 (s, 1H), 7.84 (d, 1H), 7.5 (d, 1H).

1. additionAfter the addition
2. extractionextracted with ethyl acetate (3×100 mL)
3. washThe combined organic layers were washed with saturated sodium chloride (100 mL)
4. dry with materialdried over anhydrous sodium sulfate
5. concentrationconcentrated
6. customThe obtained crude product
7. customwas purified by column chromatography (100-200 mesh silica gel)

ORD record

ord-83dc6dc539b646b9a4c1b73725c626c0

Source dataset

uspto-grants-2013_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08507681B2