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

Temperatur

-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), 7.64 (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-Eintrag

ord-e1fc14ac836846e584f89864c5b502dd

Quelldatensatz

uspto-grants-2012_10

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08288405B2